AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 254 PM MST WED JAN 31 2007 .SHORT TERM... (TONIGHT AND THURSDAY) MAIN FORECAST CONCERN REMAIN SNOW AMOUNTS TONIGHT. CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS INDICATING BROAD UPPER TROUGH ACROSS THE UPPER GREAT LAKES BACK THROUGH THE ROCKIES WITH TROUGH AXIS MOVING ACROSS NORTHWEST COLORADO ATTM. WATER VAPOR IMAGERY ALSO INDICATING YET ANOTHER SYSTEM DIVING NORTH OUT OF CENTRAL CANADA AND INTO THE NORTHERN TIER STATES ATTM. AT THE SFC...COLD FRONT WHICH BLASTED ACROSS EASTERN COLORADO EARLY THIS MORNING IS CURRENTLY BACKED UP ACROSS THE EASTERN MTS THROUGH EASTERN NEW MEXICO AND ACROSS WESTERN TEXAS PANHANDLE ATTM AS HIGH PRESSURE CONTINUES TO BUILD INTO THE SOUTHERN HIGH PLAINS. REGIONAL SATELLITE AND RADARS INDICATING CLOUD TOP COOLING AND WIDESPREAD ECHOES ACROSS WESTERN AND SOUTH CENTRAL COLORADO ATTM. FOR TONIGHT...UPPER TROUGH CONTINUES TO TRANSLATE ACROSS THE STATE WITH TROUGH AXIS MOVING ACROSS SOUTH CENTRAL COLORADO AROUND 06Z THU AND INTO SOUTHWEST KANSAS BY 12Z...AS NEXT CANADIAN SYSTEM CONTINUES TO MOVE INTO THE NORTHERN ROCKIES. MOISTURE AND LIFT ASSOCIATED WITH PASSING SYSTEM SHOULD CONTINUE TO MOVE ACROSS SOUTH CENTRAL COLORADO THIS EVENING AND INTO WESTERN KANSAS OVERNIGHT WITH ASSOCIATED PRECIPITATION DIMINISHING QUICKLY FROM WEST TO EAST WITH PASSAGE OF TROUGH AXIS...SAVE THE CENTRAL MTS WITH CONTINUED OROGRAPHIC FLOWS. HAVE KEPT CURRENT HIGHLIGHTS IN PLACE ACROSS THE SW AND CENTRAL MTS WITH ANOTHER 1 TO 4 INCHES EXPECTED THROUGH THE EVENING. SPOTTER REPORTS INDICATING GENERALLY UNDER 2 INCHES HAS FALLEN ACROSS THE EASTERN MTS ATTM...THOUGH WITH EAST TO NORTHEAST LOW LEVEL UPSLOPE CONTINUING TO DEVELOP...WILL KEPT CURRENT HIGHLIGHTS ACROSS THE SOUTHEASTERN MTS AS WELL...WITH ADDITIONAL ACCUMS BETWEEN 2 AND 6 INCHES EXPECTED...WITH HIGHEST AMOUNTS ACROSS THE SOUTHERN SANGRE DE CRISTO MTS. SNOW HAS BEEN RATHER SPOTTY ACROSS THE I-25 CORRIDOR THUS FAR...BUT EXPECT THAT TO INCREASE AS TROUGH MOVES ACROSS THE AREA WITH AN ADDITIONAL 1 TO 3 INCHES POSSIBLE...ESPECIALLY WESTERN AREAS CLOSER TO THE HIGHER TERRAIN. NOT EXPECTING MUCH IN THE WAY OF ACCUMULATING PRECIP ACROSS THE FAR EASTERN PLAINS...BUT CANT RULE OUT A FEW SNOW SHOWERS OVERNIGHT AHEAD OF PASSING SYSTEM. WITH COLD AIR IN PLACE...OVERNIGHT LOWS TO REMAIN BELOW SEASONAL AVERAGES...AND HAVE GONE AOB COOLEST GUIDANCE...ESPECIALLY THE SAN LUIS AND LOWER ARKANSAS VALLEYS WITH PARTIAL CLEARING EXPECTED BY MORNING. ON THURSDAY...NORTHWEST FLOW ALOFT INCREASES ACROSS THE STATE AS NEXT SYSTEM CONTINUES TO DIVE INTO THE NORTHERN ROCKIES WITH ASSOCIATED FRONTAL BOUNDARY PROGGED TO MOVE ACROSS NORTHEAST COLORADO BY LATE AFTERNOON. HAVE FOLLOWED CLOSER TO GFS SOLUTION WITH FASTER MOVEMENT OF FRONTAL BOUNDARY...AND HAVE INTRODUCED CHANCE POPS ACROSS THE EASTERN MTS AND ALONG THE PALMER DVD FOR THE AFTERNOON. WITH MOISTURE AND LIFT AND OROGRAPHIC FLOW INCREASING ACROSS THE CENTRAL MTS...HAVE GONE WITH LIKELY POPS WITH 1 TO 3 INCHES POSSIBLE THROUGH THE AFTERNOON. -MW .LONG TERM... (THU NIGHT THROUGH WED) ...FLUFFY SNOW ANTICIPATED FOR THU NIGHT INTO FRI... ...PREPARE NOW FOR EXTREMELY COLD TEMPERATURES FRI-WEEKEND... ...DANGEROUS WIND CHILL VALUES POSSIBLE FRI NIGHT-SAT... THU NIGHT AND FRI...NEXT CANADIAN WEATHER SYSTEM WILL BE TAKING AIM ON THE CENTRAL ROCKIES AND THIS IS STRONGEST ONE OF THE ARCTIC SYSTEM INTRUSIONS. SIGNIFICANT COLD FRONT SHOULD BE BLASTING THROUGH CO THU NIGHT AND COULD BE FASTER. A LITTLE BETTER AND DEEPER SYNOPTIC SCALE ASCENT IMPLIED GIVEN THE DYNAMICS. H5-H3 DIV-Q IMPLIED UPWARD VERTICAL MOTION JUXTAPOSED WITH H8-H7 AND H7-H6 IMPLIED UPWARD VERTICAL MOTION PER 2-D PETTERSON ANALYSES. BOTH 12KM WRF AND GFS HAVE THIS SCENARIO FOR THU NIGHT INTO FRI MORNING...SO CONFIDENCE IS SOMEWHAT HIGH OF PRECIPITATION AND ACCUMULATING SNOWFALL. HAVE INCREASED POPS TO HIGH "LIKELYS" FOR THU NIGHT INTO FRI MORNING FOR THE CENTRAL AND EASTERN MOUNTAINS INCLUDING THE I-25 CORRIDOR. GIVEN THE THERMAL STRUCTURE ALONG THE FRONT...EXCELLENT DENDRITIC SNOW GROWTH WILL BE LIKELY IN THE MOIST LAYER RESULTING IN 20-1 TO 40-1 SNOW RATIOS PRODUCING FLUFFY SNOW THAT CAN ADD UP QUICKLY IN LOW WATER CONTENT SNOWFALL. MIGHT NEED SOME ADVISORIES FOR OUR EASTERN CO MOUNTAINS AND I-25 CORRIDOR AS THE EVENT NEARS. PRECIPITATION CHANCES SHOULD BE DIMINISHING BY FRI AFTERNOON. TEMPERATURES WILL LIKELY BE STEADY OR SLOWLY FALLING FRI...BUT IF THE PRECIPITATION STOPS DURING THE THE AFTERNOON...THEN THERE COULD BE A COUPLE OF DEGREES RECOVERY. CURRENT TEMPERATURES FORECAST LOOKS ON TARGET AND ONLY MINOR SPATIAL CONSISTENCY ISSUES WERE TAKEN CARE OF. FRI NIGHT AND SAT...12KM WRF AND GFS KIND OF DIVERGE IN TERMS OF THE AMOUNT OF MIDLEVEL TEMPERATURES WARMING THAT OCCURS. THE GFS IS SLIGHTLY WARMER IN THE MIDLEVEL FRI NIGHT THROUGH SAT...WHILE THE WRF HAS H7 TEMPERATURES -18C TO -26C EVEN DURING THE DAYTIME PERIOD SAT. IT SHOULD BE MUCH BELOW AVERAGE CHILLY TEMPERATURES...EITHER EXTREMELY COLD OR VERY COLD. SUB-ZERO LOW TEMPERATURES WILL BE HIGHLY PROBABLE ACROSS MUCH SOUTHERN CO LOCATIONS FRI NIGHT AND STRUGGLING TO WARM SAT...ESPECIALLY IN TRAPPED VALLEYS AND OVER DENSE SNOW-PACK. A BIG FORECAST CONCERN WILL BE DANGEROUS WIND CHILLS FRI NIGHT INTO SAT. COULD REACH WARNING VALUES IN THE MOUNTAINS(E.G. -35F OR LOWER) AND ADVISORY TO MAYBE WARNING VALUES AT THE LOWER ELEVATIONS. MOST AREAS WILL SEE WIND CHILL VALUES OF -15F TO -35F LATE FRI NIGHT AND SAT MORNING. WIND CHILL HEADLINES MAY BE NEEDED AS THE EVENT GETS CLOSER AND THE HAZARDOUS WEATHER OUTLOOK HAS THIS HANDLED WELL RIGHT NOW. ANY PRECIPITATION POTENTIAL WOULD LIKELY BY AROUND THE CONTINENTAL DIVIDE GIVEN THE WEST-NORTHWEST FLOW ALOFT. SUN THROUGH WED...NORTHWEST FLOW DEVELOPS SUN AND INTO EARLY NEXT WEEK AS THE EXTREMELY COLD TROUGH MIGRATES EASTWARD. MIDLEVEL WARMING STARTS SUN AND THE BIGGEST CHALLENGE WILL BE WHEN AND IF THE LOW LEVEL ARCTIC AIR MASS RECEDES FROM EASTERN CO AND GETS "MIXED OUT" FROM THE HIGH MOUNTAIN VALLEYS. HAVE TRENDED TOWARDS A MODERATING TEMPERATURE TREND...BUT HELD TEMPERATURES BACK A LITTLE IN HIGH VALLEYS AND DENSE SNOW-PACK AREAS LIKE KLAA. HPC GUIDANCE HAS A SIGNIFICANT WARM-UP FORECAST FOR TUE AND WED. THIS MAY BE VALID AS A PATTERN CHANGE TO WESTERLY FLOW GIVEN MANY OF THE ENSEMBLE MEMBERS. THE CHALLENGE WILL CONTINUE TO BE THE WARM-UP OVER DENSE SNOW-PACK...WHERE HPC AND MOS GUIDANCE HAVE BEEN TOO WARM PER GRIDDED VERIFICATION DATA. METZE && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY UNTIL 11 PM MST THIS EVENING FOR COZ058>060-066- 068-072>075-079-080. && $$ 23/17 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 305 PM MST TUE JAN 30 2007 .SHORT TERM... (TONIGHT AND WEDNESDAY) SHORT TERM CONCERNS ARE TEMPERATURES ALONG WITH SNOW CHANCES AND AMOUNTS. CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS INDICATING WEST TO NORTHWEST FLOW ALOFT ACROSS THE STATE WITH ONE WEAK SHORT WAVE SHEARING APART AS IT DIVES ACROSS THE GREAT BASIN AS ANOTHER STRONGER SYSTEM CONTINUES TO DIVE OUT OF CENTRAL CANADA AND ACROSS THE NORTHERN ROCKIES ATTM. WATER VAPOR ALSO INDICATING SUBTROPICAL MOISTURE STREAMING ACROSS THE DESERT SOUTHWEST AHEAD OF OLD UPPER LOW ACROSS THE NORTHERN BAJA REGION. MODELS IN FAIR AGREEMENT WITH WEATHER DETAILS WITH INCREASING WESTERLY FLOW ALOFT ACROSS THE STATE TONIGHT AS CENTRAL CANADIAN SYSTEM AND ASSOCIATED 100+ KT JET CORE DIVES ACROSS THE NORTHERN GREAT BASIN CARVING OUT A BROAD TROUGH ACROSS THE NORTHERN ROCKIES TONIGHT. THE BROAD TROUGH ALOFT CONTINUES TO SLOWLY MOVE ACROSS THE STATE THROUGH THE DAY ON WEDNESDAY...WITH TROUGH AXIS PROGGED ACROSS CENTRAL COLORADO AT 00Z THU. FOR TONIGHT...INCREASING MOISTURE AND WEST TO SOUTHWEST FLOW PROGGED ACROSS THE CENTRAL AND SOUTHWEST MTS THROUGH THE OVERNIGHT PERIOD WITH BEST MOISTURE ACROSS THE EASTERN SAN JUAN MTS AND SOUTHERN TIER ZONES WITH PROXIMITY TO SUBTROPICAL PLUME. OROGRAPHIC SNOW MODEL YIELDING BETWEEN 2-4 INCHES ACROSS THE EASTERN SAN JUAN MTS OVERNIGHT AND ANOTHER 3-6 INCHES ON WEDNESDAY WITH INCREASING ASCENT AHEAD OF BROAD TROUGH...HAVE ISSUED A SNOW ADVISORY FROM 06Z WED THROUGH 06Z THU FOR ZONES 66 AND 68. LIGHT SNOW EXPECTED TO DEVELOP LATE TONIGHT ACROSS THE CENTRAL MTS AS WELL WITH INCREASING WESTERLY FLOW...THOUGH AMOUNTS TO REMAIN BELOW ADVISORY CRITERIA AT LEAST UNTIL LATER WEDNESDAY. OVERNIGHT LOWS TO REMAIN A CHALLENGE WITH DEVELOPING LEE TROUGHING ACROSS THE PLAINS AND SOME INCREASING HIGH CLOUDS TO HELP KEEP TEMPS UP...HOWEVER DO BELIEVE THERE WILL BE A WINDOW THIS EVENING WHERE COLD AND SNOW COVERED AREAS ACROSS THE LOWER ARKANSAS AND SAN LUIS VALLEY WILL TANK BEFORE STEADYING OUT OR WARMING INTO THE EARLY MORNING. WEDNESDAY...PASSING TROUGH SENDS ANOTHER FRONT AND RE-ENFORCING SURGE OF COLD AIR ACROSS EASTERN COLORADO EARLY WEDNESDAY MORNING...WITH FRONT MOVING ACROSS THE PALMER DVD BETWEEN 15Z AND 17Z AND ACROSS THE REST OF THE PLAINS BY EARLY AFTERNOON. WITH LIFT AND MOISTURE INCREASING ACROSS THE REGION AHEAD OF TROUGH AXIS HAVE GONE WITH LIKELY POPS ACROSS MOST OF THE HIGHER TERRAIN AND IMMEDIATE ADJACENT PLAINS AND MAINLY CHANCE POPS ACROSS THE FAR EASTERN PLAINS. MODEL CROSS SECTIONS INDICATING GOOD DENDRITIC GROWTH POTENTIAL WITH TEMPS BETWEEN -14C AND -20C WITHIN THE MOIST LAYER...WITH LATER SHIFTS POSSIBLY HOISTING HIGHLIGHTS ACROSS THE CENTRAL AND EASTERN MTS WITH SNOW ACCUMS BETWEEN 4-8 INCHES POSSIBLE. WITH THE FRONT MOVING ACROSS THE PLAINS IN THE MORNING WILL LIKELY SEE HIGHS BY THE LATE MORNING WITH DECREASING TEMPERATURES THROUGH THE AFTERNOON. -MW .LONG TERM... (WED NIGHT THROUGH TUE) ...WINTRY WEATHER WILL CONTINUE THROUGH AT LEAST SUN... ...PREPARE NOW FOR EXTREMELY COLD TEMPERATURES FRI-WEEKEND... WED NIGHT AND THU...THE COMBINATION OF A LONGWAVE TROUGH AND YET ANOTHER COLD FRONTAL SURGE SHOULD BRING THE POTENTIAL FOR FLUFFY SNOWFALL AND COLD TEMPERATURES. H7 TEMPERATURES ARE FORECAST TO RANGE FROM -12C TO -15C. SHOULD SEE PLENTY OF SYNOPTIC SCALE ASCENT TO SQUEEZE OUT SNOWFLAKES FROM THE CLOUD COVER. COULD SEE ANOTHER 3-5 INCHES OVER THE MOUNTAINS AND 1-3 INCHES ACROSS THE LOWER ELEVATIONS OF SOUTH CENTRAL AND SOUTHEAST CO. MIGHT NEED AN ADVISORY FOR OUR EASTERN CO MOUNTAINS AND ADJACENT I-25 CORRIDOR THROUGH WED EVENING...IF THE POTENTIAL SNOW EVENT STILL LOOKS GOOD. IT APPEARS THE PRECIPITATION POTENTIAL SHOULD DIMINISH LATE WED NIGHT AND COULD PICKUP AGAIN AROUND THE CONTINENTAL DIVIDE THU AFTERNOON. THERE COULD BE A BRIEF RESPITE OF THE FLUFFY SNOW POTENTIAL ON THU UNTIL THE NEXT WEATHER SYSTEM TAKES AIM FOR THU NIGHT THROUGH FRI NIGHT. I HAVE INCREASE POPS TO CATEGORICAL ACROSS THE SOUTHWEST MOUNTAINS HIGHER TERRAIN WED EVENING GIVEN THE SNOW ADVISORY. ALSO...INCREASED POPS TO HIGH "CHANCE" AND "LIKELY" FOR THE REMAINDER OF THE MOUNTAINS AND I-25 CORRIDOR FOR WED EVENING. DECREASED OR REMOVED POPS FOR THU...BUT MAINTAINED SOME LOW POPS AROUND THE CONTINENTAL DIVIDE. FRI THROUGH SUN...DEEP LONGWAVE TROUGH EXTENDS FROM THE POLAR LOW OVER CENTRAL CANADA INTO THE CENTRAL ROCKIES. THERE HAS BEEN RELATIVELY GOOD CONSISTENCY ON THIS PATTERN DEVELOPING FOR LATE THIS WEEK INTO THE WEEKEND. FOLLOWED THE 06Z/30 DGEX GIVEN THE FINER TERRAIN RESOLUTION. H7 TEMPERATURES ARE PROGGED TO RANGE FROM -18C TO -28C FRI AND SLIGHTLY WARMING THROUGH THE WEEKEND. HIGH AND LOW TEMPERATURES WILL LIKELY BE IN THE SUB-ZERO VALUES FOR OUR MOUNTAINS AND HIGH VALLEYS THROUGH THE WEEKEND. ALSO...THE SOUTHEAST CO PLAINS WILL RANGE FROM SUB-ZERO VALUES INTO THE TEENS. FRI COULD BE A BRUTAL DAY. GIVEN THE POTENTIAL SYNOPTIC ASCENT AND THERMAL STRUCTURE PROJECTED FOR FRI-SAT...HIGH SNOW RATIOS WILL BE LIKELY 20-1 TO 40-1...SO JUST A MINUTE AMOUNT OF QPF COULD PRODUCE 1-6 INCHES OF FLUFFY SNOW. INCREASED POPS TO HIGH "CHANCE" FOR THE MOUNTAINS AND I-25 CORRIDOR ON FRI...AND CONTINUED "SLIGHT CHANCE" TO NO MENTION OVER THE WEEKEND. WHILE WIND SPEEDS WILL NOT BE ALL THAT STRONG...IT WILL NOT TAKE MUCH WIND SPEED TO DROP THE WIND CHILL VALUES GIVEN THE EXTREMELY COLD TEMPERATURES. WIND CHILL READINGS OF -25F TO -35F IN THE MOUNTAINS AND -20F TO 0F WILL BE COMMON FRI THROUGH THE WEEKEND. MON AND TUE...MEDIUM RANGE MODELS PROJECTING NORTHWEST FLOW TO DEVELOP OVER THE ROCKIES AS THE EXTREMELY COLD LONGWAVE TROUGH MIGRATES EASTWARD. A BIG CHALLENGE IF AND WHEN THE MODIFIED ARCTIC AIR MASS WILL RECEDE ACROSS EASTERN CO. AGAIN...FOLLOWED THE 06Z/30 DGEX FINER TERRAIN RESOLUTION MODULE. WILL PLAY A MODERATING TEMPERATURE TREND...EXCEPT FOR THE LOWER AR RIVER VALLEY IN EXTREME SOUTHEAST CO GIVEN THE 1-2 FEET OF SNOW PACK...AND POSSIBLY MORE...THAT WILL BE OVER THIS AREA. MOS/HPC GUIDANCE HAS BEEN 10-20 DEGREES TOO WARM IN THESE DENSE SNOW PACK AREAS. IT HAS BEEN SEVERAL WEEKS SINCE KLAA WAS 35F OR GREATER...SO WILL KEEP TEMPERATURES ON THE COLD SIDE UNTIL THEY REACH ABOVE 35F. METZE && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY FROM 11 PM THIS EVENING TO 11 PM MST WEDNESDAY FOR COZ066-068. && $$ 23/17 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 954 AM EST WED JAN 31 2007 .DISCUSSION... CURRENT...WRN ATLC LOW PRES HAS DRAGGED A WEAK FRONTAL TROUGH ACROSS NRN/CTRL FL. DUE TO DVLPG LOW PRES OVER THE WRN GOMEX THE TROUGH HAS SLOWED CONSIDERABLY AND IS ALREADY FALLING APART AS I TYPE. NORTH OF THIS DISSIPATING FEATURE...EXPANSIVE SFC HIGH PRES RIDGE HAS MOVED INTO THE MID MS/OH/TN VLYS. MORNING RAOBS/RUC ANLYS FIELDS INDICATE THE LARGE SWATH OF >90% H70-H50 RH WHICH MOVED OVER THE STATE LAST NIGHT...PRODUCING NMRS SPRINKLES IS MOVING OFF TO THE EAST. FIRST HR OR SO OF VIS SATELLITE IMAGERY SHOWS THAT LAST NIGHT`S EXTENSIVE MID LEVEL CLOUD CANOPY IS THINNING OUT QUITE A BIT ATTM. TODAY...EXPECT ENOUGH BREAKS TO DEVELOP THIS AFTN FOR SKIES TO WIND UP AVGING "PSUNNY"...HOWEVER WILL KEEP AN EYE ON WHAT APPEARS TO BE A WEAK LOW/MID LEVEL VORT IN THE GOMEX BTWN BUOYS 42001/42003 TO SEE IF IT MIGHT HAVE THE POTENTIAL SPREAD ADDITIONAL CLOUDS THIS WAY BY LATE AFTN...BUT FOR NOW IT APPEARS THAT THIS WON`T BE THE CASE. GIVEN THIS...WE SHOULD WIND REACHING FCSTR MAX TEMPS CWA-WIDE...AND DON`T SEE A PRESSING NEED FOR A ZFP UPDATE. && .AVIATION...VFR WITH DCRSG COVRG OF BKN MID LEVEL CIGS. && .MARINE...LATEST BUOY OBS CONTINUE TO SHOW N-NNW WINDS OF 15-20KT. NEAR SHORE. OVER THE LAST 2HR...SCRIPPS BUOY 41114 (OFFSHORE FPR) HAS ACTUALLY NUDGED INTO THE 3-4FT RANGE...ABOVE THE CURRENT FCST. ALL INDICATIONS FOR THE SHORT RANGE GUIDANCE IS THAT THE LOCAL PGRAD WILL SLACKEN THIS AFTN...ALLOWING WINDS TO DROP OFF TO 10-15KT AS THE FLOW VEERS FROM N TO NE. HOWEVER...GIVEN THE CURRENT CONDS... PLAN TO KEEP CAUTIONARY STMT FOR THE FLG-COF 20-60NM LEG GOING THRU EARLY AFTN. WILL ALSO TWEAK SEAS OVER THE 0-20NM COF-JUP LEG UP TO 2-4FT TO ACCT FOR CURRENT CONDS. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ CRISTALDI fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 500 AM EST WED JAN 31 2007 .SYNOPSIS... 07Z WATER VAPOR AND RUC ANALYSIS SHOWING A FAIRLY ACTIVE PATTERN ACROSS THE CONUS. SEVERAL VERY DISTINCT SHORTWAVES CAN BE SEEN RIDING THE NORTHERN STREAM...ONE DROPPING OUT OF SOUTH-CENTRAL CANADA INTO THE NORTHERN PLAINS AND ANOTHER ABOUT TO EXIT THE CAROLINA COAST. WEAKLY AMPLIFIED RIDING IS SEEN ACROSS THE LOWER MISSISSIPPI VALLEY FOLLOWED CLOSELY BY ENERGY PUSHING ACROSS THE SOUTHWEST UNITED STATES. AT THE SURFACE WE SEE HIGH PRESSURE BUILDING TO OUR NORTH ACROSS THE TENNESSEE VALLEY. A COLD FRONT ALONG THE LEADING EDGE OF THIS HIGH IS NOW PUSHING THROUGH THE FORECAST AREA BRINGING ANOTHER SHOT OF COOL AND DRY AIR FOR TODAY. LATEST SATELLITE IMAGERY SHOWS THE BACK EDGE OF THE CLOUDS CONTINUING TO PROGRESS EAST AND SOUTHEAST ACROSS THE AREA. MOST LOCATIONS SHOULD SEE A PARTLY TO MOSTLY SUNNY MORNING WITH THE EXCEPTION THE THE SOUTHEAST BIG BEND WHICH WILL TAKE A BIT LONGER TO CLEAR OUT. NEARLY STATIONARY WEAK LOW PRESSURE CAN ALSO BE SEEN IN THE WESTERN GULF. THIS LOW WILL WEAKEN TODAY AND THEN BE REPLACED BY A MUCH MORE DYNAMIC SYSTEM THAT SHOULD BE OUR NEXT WEATHER MAKER STARTING LATE TONIGHT AND THROUGH THE DAY ON THURSDAY. && .SHORT TERM... (TODAY-FRIDAY) AS MENTIONED ABOVE COLD FRONT WILL CLEAR SOUTH OF THE FORECAST AREA DURING THE MORNING HOURS TODAY. THE CLOUDS WILL CONTINUE TO PUSH SOUTH AS WELL WITH PARTLY TO MOSTLY SUNNY SKIES FOR MOST LOCATIONS THIS MORNING. LOW PRESSURE WILL BEGIN TO TAKE SHAPE IN THE WESTERN GULF THIS AFTERNOON WITH A DEVELOPING WARM FRONT MOVING TOWARD THE NORTH-CENTRAL GULF COAST BY LATE IN THE DAY. WOULD EXPECT TO SEE HIGH CLOUDS ASSOCIATED WITH THIS FEATURE BEGIN TO OVERSPREAD OUR SKIES BY LATER TODAY AND ESPECIALLY DURING THE EVENING HOURS. WITH COLD AIR ADVECTION THROUGH THE DAY...HIGH TEMPERATURES WILL BE ON THE COOL SIDE ONLY REACHING INTO THE MIDDLE 50 MOST LOCATIONS. RAIN CHANCES WILL BEGIN TO INCREASE FROM WEST TO EAST TONIGHT AS THE WARM FRONT ASSOCIATED WITH THE DEVELOPING STORM IN THE WESTERN GULF BEGINS TO APPROACH. NOT THINKING THAT THE RAIN TONIGHT WILL BE ALL THAT HEAVY...BUT COVERAGE COULD BECOME QUITE WIDESPREAD AFTER MIDNIGHT IN THE WESTERN HALF OF THE CWA. LOW BEINGS TO INTENSIFY AND MOVE NORTHEAST ON THURSDAY. GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON A LOW POSITION SOMEWHERE NEAR OR JUST NORTH OF MOBILE ALABAMA BY THURSDAY EVENING. THE WARMFRONT SHOULD SLOWLY PUSH NORTH THROUGH THE DAY...ALTHOUGH WIDESPREAD AREAS OF SHOWER AND ISOLATED THUNDERSTORMS WILL HELP TO SLOW THE FRONTS PROGRESS. RAINFALL ON THURSDAY MAY BE MODERATE TO HEAVY AT TIMES...ESPECIALLY FROM THE AFTERNOON INTO THE OVERNIGHT HOURS. TEMPERATURES WILL BE QUITE TRICKY. MOST SO ACROSS THE NORTH. RIGHT NOW WILL BE GOING WITH HIGHS FROM NEAR 60 NORTH TO THE MIDDLE/UPPER 60 SOUTH. TEMPERATURES ACROSS THE NORTH ARE LIKELY TO BE RATHER COOL THROUGH A GOOD PORTION OF THE DAY UNTIL THE WARM FRONT CAN PUSH THROUGH. FOR THAT REASON THE HIGH NEAR 60 ACROSS OUR NORTHERN AL/GA COUNTIES WILL LIKELY WAIT TO VERY LATE IN THE DAY. ALSO AS THE DAY PROGRESSES...JUST ENOUGH INSTABILITY IS POSSIBLE FOR ISOLATED TO SCATTERED THUNDERSTORMS IN THE WARM SECTOR BEHIND THE WARM FRONT. SHEAR PROFILES LOOK IMPRESSIVE ENOUGH TO PRODUCE A FEW STRONG THUNDERSTORMS AND SPC HAS OUTLOOKED PORTIONS OF OUR AREA FOR A SLIGHT RISK OF SEVERE WEATHER. THE LOW WILL PUSH OFF THE SOUTHEAST COAST LATE THURSDAY NIGHT DRAGGING AN ASSOCIATED COLD FRONT THROUGH AREA. SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH MUCH OF THE NIGHT UNTIL THIS FRONT HAS PASSES...ESPECIALLY IN THE EAST. ONCE AGAIN SOME OF THE RAINFALL MAY BE ON THE HEAVY SIDE AT TIMES. EXACT AMOUNTS ARE UNCERTAIN BUT A GOOD PORTION OF THE FORECAST AREA IS LIKELY TO SEE 1"+ RAINFALL WITH THIS SYSTEM WITH THE POTENTIAL FOR MORE. WILL OUTLOOK AS WELL IN THE HWO. COLD FRONT WILL BE SLOW TO CLEAR THE SOUTHEAST BIG BEND WITH A FEW LINGERING SHOWERS LIKELY INTO FRIDAY MORNING. GUIDANCE SPLITS AT THIS POINT...WITH THE GFS CLEARING US OUT AND THE NAM HOLDING THE FRONT AND SHOWER ACTIVITY ACROSS OUR SOUTHERN ZONES. NAM IS AN OUTLIER IN ITS SOLUTION WITH THE GFS HAVING STRONG BACKING FROM THE ECMWF. FOR THIS REASON DROPPED POPS BY LATE FRIDAY THROUGH FRIDAY NIGHT FOR MOST LOCATIONS. .LONG TERM... (SATURDAY-WEDNESDAY) AREA IS IN THE SQUEEZE ON SATURDAY AND SATURDAY NIGHT BETWEEN HIGH PRESSURE TO OUR NORTH AND THE FRONT TO SOUTH SOUTH TRYING TO COME BACK NORTH. GFS HAS BEEN VERY PERSISTENT ON BRINGING QPF BACK INTO THE SOUTHEAST HALF OF THE AREA BY LATE SATURDAY AND THROUGH SATURDAY NIGHT. RAN THE FORECAST IN A SIMILAR FASHION WITH SLIGHT CHANCE POPS NORTHWEST TO LIKELY POPS IN THE FAR SOUTHEAST. EITHER WAY...HIGH PRESSURE TO THE NORTH LOOKS TO WIN THE BATTLE BY SUNDAY WITH THE PRECIP PUSHING SOUTH AND EAST OF THE AREA BY EARLY AFTERNOON. JUST FOR MENTIONING...THE AIRMASS COMING INTO THE REGION SATURDAY NIGHT INTO SUNDAY IS RATHER COLD. IF...IF THERE WAS ANY LINGERING LIGHT SHOWER ACTIVITY ACROSS SOUTHEAST ALABAMA OR SOUTHWEST GEORGIA...THICKNESS VALUES BOTH (1000-850/850-700) WOULD INDICATED THE POTENTIAL FOR A FEW FLAKES OF SNOW TO MIX IN. AT THIS TIME THE THINKING IS THAT THE PRECIP WILL EXIT TO RAPIDLY...BUT THERE IS A CHANCE. EITHER WAY ANY LINGERING PRECIP WOULD BE VERY LIGHT AND ANY FROZEN PRECIP WOULD NOT AMOUNT TO MUCH. UPPER PATTERN FOR THE FIRST PART OF NEXT WEEK WILL FEATURE A VERY DEEP AND COLD UPPER LEVEL TROUGH IN THE EASTERN CONUS AND SURFACE HIGH PRESSURE TO OUR NORTH. AT THIS TIME IT LOOKS DRY BUT COOL FOR THE MONDAY-WEDNESDAY TIMEFRAME. && .AVIATION... DESPITE WIDESPREAD OVERCAST CONDITIONS AND OCCASIONAL SPRINKLES SO FAR TONIGHT...VFR WEATHER IS BEING REPORTED AT ALL OF OUR LOCAL STATIONS. THE CEILINGS (AROUND 8K FT) WILL GRADUALLY DISSIPATE FROM NORTHWEST TO SOUTHEAST BETWEEN NOW AND DAY BREAK...AS WILL THE VERY LIGHT SHOWERS. IN FACT...ANY SHOWERS THAT OCCUR TONIGHT WILL BE OF LITTLE IMPACT TO OPERATIONS. WINDS WILL GENERALLY BE 10 KT OR LESS TONIGHT AND WEDNESDAY...AND QUICKLY VEER FROM NORTHWEST EARLY TODAY...TO EAST BY WEDNESDAY EVENING. A MORE SIGNIFICANT WEATHER SYSTEM WILL DEVELOP IN THE GULF AND APPROACH LATER TODAY AND TONIGHT...BUT IT IS STILL A BIT TOO EARLY TO FORECAST ANY RAIN THROUGH 06 UTC. && .MARINE... HIGH PRESSURE BRIEFLY BUILDS ACROSS THE COASTAL WATERS TODAY BEFORE RAPIDLY MOVING OFF THE SOUTHEAST COAST AS LOW PRESSURE DEVELOPS IN THE WESTERN GULF. THE TIGHTENING GRADIENT BETWEEN THIS HIGH AND THE DEVELOPING LOW WILL INCREASE WINDS AND SEAS TO CAUTION LEVELS IN THE OFFSHORE LEGS TODAY AND FOR ALL LEGS TONIGHT. THIS LOW WILL INTENSIFY AS IT MOVES NORTH OF THE COASTAL WATERS THURSDAY AND THURSDAY NIGHT. WIND AND SEAS ARE ANTICIPATED TO REACH ADVISORY LEVELS THURSDAY INTO THURSDAY NIGHT WITH WIDESPREAD SHOWERS AND THUNDERSTORMS. SOME OF THE STORMS WILL HAVE THE POTENTIAL TO BECOME STRONG TO SEVERE. COLD FRONT WILL CROSS THE WATERS THURSDAY NIGHT AND EARLY FRIDAY WITH HIGH PRESSURE BRIEFLY BUILDING IN BY LATE IN THE DAY. GRADIENT WILL TIGHTEN ONCE AGAIN FOR THE UPCOMING WEEKEND BETWEEN THE FRONT TO OUR SOUTH AND STRONG HIGH PRESSURE BUILDING TO OUR NORTH. EXPECT AN EXTENDED PERIOD OF CAUTION LEVEL WINDS FROM THE NORTH AND NORTHEAST BOTH SATURDAY AND SUNDAY. && .FIRE WEATHER... CANCELLED THE RED FLAG WARNING FOR OUR GEORGIA COUNTIES FOR THIS AFTERNOON...DEWPOINTS HAVE BEEN PERSISTENTLY TOO LOW IN THE GUIDANCE AND ADJUSTED CURRENT GRIDS TO REFLECT THIS. RH VALUES ARE NO LONGER ANTICIPTATED TO REACH CRITICAL DURATIONS. RED FLAG WARNING REMAIN IN EFFECT FOR PORTIONS OF THE EASTERN FLORIDA PANHANDLE AND BIG BEND REGIONS. INCREASING MOISTUREA AND RAIN CHANCES FOR THURSDAY WILL END ANY FIRE WX THREAT. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 54 43 67 56 66 / 10 60 90 90 30 PANAMA CITY 54 49 67 56 65 / 10 70 90 90 20 DOTHAN 51 43 62 49 63 / 10 70 90 80 20 ALBANY 51 41 62 49 64 / 0 50 90 90 20 VALDOSTA 54 42 68 57 66 / 10 40 80 90 30 CROSS CITY 57 46 69 61 69 / 10 40 70 80 50 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING FROM NOON EST /11AM CST/ TODAY TO 5 PM EST /4 PM CST/ THIS AFTERNOON FOR THE FOLLOWING ZONES: CALHOUN...DIXIE ...GADSDEN...HOLMES...INLAND WALTON...JACKSON...JEFFERSON...LAFAYETTE ...LEON...LIBERTY...MADISON...TAYLOR...WAKULLA...AND WASHINGTON. GMZ750...NONE. GMZ755...NONE. GMZ770...NONE. GMZ775...NONE. && $$ AVIATION...FOURNIER REST OF DISCUSSION...MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 226 AM EST TUE JAN 30 2007 .AVIATION... NEXT MESO VORT WILL MOVE SOUTH DOWN LAKE MICHIGAN AND SHOULD EVENTUALLY TURN SE. LATEST NAM/WRF WHICH APPEARS TO HAVE A GOOD HANDLE ON THIS SYSTEM AS LATEST RADAR AND SATELLITE ALREADY STARTING TO SHOW THIS SYSTEM TURNING TO THE SOUTHEAST. SBN AND FWA SHOULD BE WITHIN OR CLOSE TO THE SOUTHERN PERIPHERY SO HAVE TRIED TO INDICATE SOME TIMING HERE. WINDS SHOULD BACK TO THE SW OVERNIGHT...WITH SNOW DIMINISHING TO FLURRIES OR ENDING. THE SYSTEM SHOULD TEND TO WEAKEN SOME AS IT MOVE FARTHER INLAND. && .UPDATE... HAVE UPDATED FOR SMALL LOW/MESO LOW ASSOCIATED WITH IMPRESSIVE SHORT TERM SNOWFALL AMOUNTS. THIS SYSTEM HAS BEEN TRACKING SE OVER FAR SOUTHERN LOWER MICHIGAN AND NORTHERN INDIANA. SBN MEDIA REPORTED AMOUNTS SIMILAR TO WEEKEND BERRIEN COUNTY SNOWFALL RATES OF 5 INCHES IN 3 HOURS. WITH LIGHTER/DRIER SNOW AND WINDS 15 TO 25 MPH...PLENTY OF BLOWING AND DRIFTING SNOW ALREADY AND SHOULD PERSIST. EXPECT SNOWFALL TO DROP OFF AS MESO LOW MOVES DEEPER INLAND. GIVEN ANOTHER IN A SERIES OF MESO LOWS UPSTREAM OVER CENTRAL LAKE MICHIGAN...HAVE ADDED A SNOW AND BLOWING SNOW ADVISORY THROUGH EARLY TONIGHT... ALTHOUGH SHOULD BE SOMEWHAT OF A BREAK IN SNOWFALL THIS AFTERNOON BETWEEN SYSTEMS... EXCEPT FOR AREAS CLOSER TO DOWNSTREAM OF LAKE MICHIGAN. && .PREV DISCUSSION... /ISSUED 404 AM EST TUE JAN 30 2007/ SHORT TERM... TODAY AND TONIGHT. WILL BE USING THE LATEST RUC AND 00Z NAM-WRF FOR THE SHORT TERM FCST AS THEY SEEM TO HAVE A DECENT HANDLE ON THE SYNOPTIC AND MESOSCALE SITUATION. SFC ANALYSIS AT 08Z DEPICTED A CLIPPER SYSTEM ACRS THE WRN GREAT LAKES REGION. THE MAIN SFC LOW WAS LOCATED OVER WRN MICHIGAN WITH A COLD FRONT TRAILING FROM THE LOW INTO WRN INDIANA...THEN BACK INTO THE SRN PLAINS. THE MAIN SFC LOW AND COLD FRONT WILL MOVE RAPIDLY EAST THIS MORNING AWAY FROM THE REGION. KIWX RADAR WAS SHOWING A DECENT SIZE OF SNOW OUT AHEAD OF THIS FRONT OVER THE ERN TWO THIRDS OF THE FCST AREA. SOME OF THE SNOW WAS LOCALLY HEAVY IN SPOTS AS INDICATED BY THE 08Z KFWA OBSERVATION WHICH REPORTED AN INCH IN ONE HOUR. THIS SNOW WILL QUICKLY MOVE EAST EARLY THIS MORNING...AND SHOULD BE EXISTING THE ERN FCST AREA BETWEEN 5 AND 6 AM. TO THE WEST...AN UPR LVL VORT MAX WAS LOCATED OVER NRN IL. THIS FEATURE WILL SWEEP ACRS NRN INDIANA BETWEEN 12Z AND 18Z...BRINING A ROUND OF SNOW SHOWERS. TO ADD TO THE MIX...LAKE EFFECT SNOW SHOWERS WILL DEVELOP AFTER 15Z AS THE MEAN LOW LVL FLOW VEERS TO A 290 DIRECTION. MODELS INDICATE THERE COULD BE A BREAK IN THE WIDESPREAD PCPN...EXCEPT IN THE LAKE EFFECT REGIONS OF MICHIGAN AND FAR NRN INDIANA...BY THIS AFTN...BUT WILL NOT TRY TO TIME THIS ATTM. GUSTY WEST TO NORTHWEST WINDS OF 25 TO 30 MPH WILL CAUSE SOME BLOWING OF SNOW...AND HAVE ADDED THIS TO THE ZONES ACRS NRN INDIANA...SRN MICHIGAN AND FAR NORTHWEST OHIO. SNOWFALL AMOUNTS TODAY WILL RANGE FROM AROUND A HALF INCH SOUTH TO 4 INCHES IN BERRIEN AND CASS COUNTIES...WHERE A LAKE EFFECT SNOW ADVISORY WILL REMAIN IN EFFECT. FOR TONIGHT...MEAN LOW LVL FLOW WILL VEER A LITTLE MORE TO THE NORTHWEST...ABOUT 300 DEGREES. ONE LAST SURGE OF LAKE EFFECT SNOW IS EXPECTED DOWNWIND OF LAKE MICHIGAN DURING THE EVENING. THEREAFTER...INVERSION HEIGHTS WILL BEGIN TO LOWER AND DRIER AIR WILL GRADUALLY WORK INTO THE REGION FROM THE WEST TO CAUSE THE LAKE EFFECT PCPN TO DWINDLE CONSIDERABLY AFTER 06Z WEDNESDAY. WILL RAISE POPS ACRS THE MICHIGAN/FAR NRN INDIANA COUNTIES THIS EVENING IN ANTICIPATION OF THE LAST ROUND OF LAKE EFFECT PCPN. ADDITIONAL SNOWFALL AMOUNTS WILL RANGE FROM A TRACE SOUTH (FLURRIES) TO 1 TO 2 INCHES ACRS FAR NRN INDIANA/SOUTHERN MICHIGAN. SINCE POPS WILL BE RAISED TO LIKELY ACRS THE NORTH...WILL EXTEND THE LAKE EFFECT SNOW ADVISORY FOR BERRIEN AND CASS COUNTIES TO 06Z...OR 1 AM EDT. TOTAL SNOW ACCUMULATION WILL RANGE BETWEEN 4 AND 7 INCHES ACRS THE ADVISORY AREA. AS FOR TEMPS TODAY...THEY WILL BE TRICKY AS COLD ARCTIC AIR WILL CAUSE TEMPS TO TUMBLE INTO THE 10 TO 15 DEGREE RANGE BY MID MORNING ACRS THE SWRN CWFA. TEMPS WILL REMAIN SLIGHTLY WARMER DOWNWIND OF LAKE MICHIGAN. THEREAFTER...ONLY A SLIGHT DIURNAL RISE IS EXPECTED THIS AFTN. FOR TONIGHT...LOWS WILL DIP INTO THE SINGLE DIGITS ACRS MOST OF THE REGION...EXCEPT FOR LOCATIONS NEAR THE LAKE. WHERE TEMPS WILL REMAIN IN THE 10 TO 15 DEGREE RANGE. LONG TERM... WEDNESDAY THROUGH MONDAY. THE ARCTIC EXPRESS CONTINUES TO BE THE WX FOCUS THROUGH THE FORECAST PERIOD. BELOW NORMAL TEMPERATURES AND PERIODS OF SNOW WILL BE THE RULE. FORECAST MODELS HAVE BEEN RELATIVELY STABLE IN SOLUTION...SO NO REASON TO MAKE BIG CHANGES TO ONGOING FORECAST. AS POLAR VORTEX GRADUALLY SINKS SOUTH INTO SOUTHERN CANADA...SURGES OF COLDER AIR CONTINUE TO REINFORCE THE ALREADY BELOW NORMAL CONDITIONS. THE COLD AIR CONTINUES TO CAUSE LAKE EFFECT SNOW SHOWERS TO DEVELOP WHEN THE WIND DIRECTION IS FAVORABLE. WITH THE UPPER LOW IN THE AREA...A VERY UNSETTLED WEATHER PATTERN CONTINUES AS SPOKES OF ENERGY ROTATE AROUND THE UPPER LOW. THEREFORE...MOST PERIODS HAVE A MENTION OF SNOW THROUGH THE FORECAST PERIOD. COLDEST AIR OF THE SEASON IS FORECAST INTO THE AREA THIS WEEKEND. WITH FRESH SNOW COVER AND STRONG CAA...MIN TEMPS COULD APPROACH OR FALL BELOW ZERO AND MAXS WOULD STRUGGLE TO CLIMB OUT OF THE SINGLE DIGITS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...SNOW AND BLOWING SNOW ADVISORY UNTIL 1 AM EST WEDNESDAY FOR INZ004>009-016>018. MI...SNOW AND BLOWING SNOW ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MIZ079>081. LAKE EFFECT SNOW WARNING UNTIL 1 AM EST WEDNESDAY FOR MIZ077-078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR LMZ043-046. && $$ SHORT TERM...SKIPPER AVIATION...HICKMAN LONG TERM....EDDY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1150 AM EST TUE JAN 30 2007 .UPDATE... HAVE UPDATED FOR SMALL LOW/MESO LOW ASSOCIATED WITH IMPRESSIVE SHORT TERM SNOWFALL AMOUNTS. THIS SYSTEM HAS BEEN TRACKING SE OVER FAR SOUTHERN LOWER MICHIGAN AND NORTHERN INDIANA. SBN MEDIA REPORTED AMOUNTS SIMILAR TO WEEKEND BERRIEN COUNTY SNOWFALL RATES OF 5 INCHES IN 3 HOURS. WITH LIGHTER/DRIER SNOW AND WINDS 15 TO 25 MPH...PLENTY OF BLOWING AND DRIFTING SNOW ALREADY AND SHOULD PERSIST. EXPECT SNOWFALL TO DROP OFF AS MESO LOW MOVES DEEPER INLAND. GIVEN ANOTHER IN A SERIES OF MESO LOWS UPSTREAM OVER CENTRAL LAKE MICHIGAN...HAVE ADDED A SNOW AND BLOWING SNOW ADVISORY THROUGH EARLY TONIGHT... ALTHOUGH SHOULD BE SOMEWHAT OF A BREAK IN SNOWFALL THIS AFTERNOON BETWEEN SYSTEMS... EXCEPT FOR AREAS CLOSER TO DOWNSTREAM OF LAKE MICHIGAN. && .AVIATION... AN UPR LVL VORT MAX AND ASSOCD SFC TROF WILL MOVE ACRS NRN INDIANA BETWEEN 12Z AND 18Z. LATEST KIWX RADAR INDICATED A LOW LVL MESOSCALE LAKE MICHIGAN VORTICITY MOVING INTO SOUTHWEST LOWER MICHIGAN AND FAR NORTHWEST INDIANA. THIS FEATURE WILL LIKELY DROP VSBYS TO A 1/2SM MILE FOR A COUPLE HOURS AT KSBN. THEREAFTER...ONLY SCATTERED SNOW SHOWERS AND MVFR CONDITIONS CAN BE EXPECTED AT KSBN UNTIL THIS EVENING. FOR KFWA...MVFR CIGS/VSBYS CAN BE EXPECTED THROUGH 15Z...THEN VSBYS WILL IMPROVE TO P6SM WITH ONLY A SCATTERING OF LIGHT SNOW SHOWERS IN THE VICINITY. FOR TONIGHT...ANOTHER SFC TROF AND LAST SURGE OF LAKE EFFECT SNOW IS FORECAST TO MOVE ACRS THE KSBN TAF SITE BETWEEN 00Z AND 06Z. WILL INCLUDE A PERIOD OF IFR CONDITIONS DURING THIS TIME FRAME. LAKE EFFECT SNOW SHOWERS WILL DIMINISH TO FLURRIES AND WILL PUSH NORTH INTO MICHIGAN AFTER 06Z. SFC HIGH PRESSURE IS FORECAST TO BUILD INTO THE REGION AFTER 12Z WEDNESDAY WITH VFR CONDITIONS RETURNING TO THE REGION. && .PREV DISCUSSION... /ISSUED 404 AM EST TUE JAN 30 2007/ SHORT TERM... TODAY AND TONIGHT. WILL BE USING THE LATEST RUC AND 00Z NAM-WRF FOR THE SHORT TERM FCST AS THEY SEEM TO HAVE A DECENT HANDLE ON THE SYNOPTIC AND MESOSCALE SITUATION. SFC ANALYSIS AT 08Z DEPICTED A CLIPPER SYSTEM ACRS THE WRN GREAT LAKES REGION. THE MAIN SFC LOW WAS LOCATED OVER WRN MICHIGAN WITH A COLD FRONT TRAILING FROM THE LOW INTO WRN INDIANA...THEN BACK INTO THE SRN PLAINS. THE MAIN SFC LOW AND COLD FRONT WILL MOVE RAPIDLY EAST THIS MORNING AWAY FROM THE REGION. KIWX RADAR WAS SHOWING A DECENT SIZE OF SNOW OUT AHEAD OF THIS FRONT OVER THE ERN TWO THIRDS OF THE FCST AREA. SOME OF THE SNOW WAS LOCALLY HEAVY IN SPOTS AS INDICATED BY THE 08Z KFWA OBSERVATION WHICH REPORTED AN INCH IN ONE HOUR. THIS SNOW WILL QUICKLY MOVE EAST EARLY THIS MORNING...AND SHOULD BE EXISTING THE ERN FCST AREA BETWEEN 5 AND 6 AM. TO THE WEST...AN UPR LVL VORT MAX WAS LOCATED OVER NRN IL. THIS FEATURE WILL SWEEP ACRS NRN INDIANA BETWEEN 12Z AND 18Z...BRINING A ROUND OF SNOW SHOWERS. TO ADD TO THE MIX...LAKE EFFECT SNOW SHOWERS WILL DEVELOP AFTER 15Z AS THE MEAN LOW LVL FLOW VEERS TO A 290 DIRECTION. MODELS INDICATE THERE COULD BE A BREAK IN THE WIDESPREAD PCPN...EXCEPT IN THE LAKE EFFECT REGIONS OF MICHIGAN AND FAR NRN INDIANA...BY THIS AFTN...BUT WILL NOT TRY TO TIME THIS ATTM. GUSTY WEST TO NORTHWEST WINDS OF 25 TO 30 MPH WILL CAUSE SOME BLOWING OF SNOW...AND HAVE ADDED THIS TO THE ZONES ACRS NRN INDIANA...SRN MICHIGAN AND FAR NORTHWEST OHIO. SNOWFALL AMOUNTS TODAY WILL RANGE FROM AROUND A HALF INCH SOUTH TO 4 INCHES IN BERRIEN AND CASS COUNTIES...WHERE A LAKE EFFECT SNOW ADVISORY WILL REMAIN IN EFFECT. FOR TONIGHT...MEAN LOW LVL FLOW WILL VEER A LITTLE MORE TO THE NORTHWEST...ABOUT 300 DEGREES. ONE LAST SURGE OF LAKE EFFECT SNOW IS EXPECTED DOWNWIND OF LAKE MICHIGAN DURING THE EVENING. THEREAFTER...INVERSION HEIGHTS WILL BEGIN TO LOWER AND DRIER AIR WILL GRADUALLY WORK INTO THE REGION FROM THE WEST TO CAUSE THE LAKE EFFECT PCPN TO DWINDLE CONSIDERABLY AFTER 06Z WEDNESDAY. WILL RAISE POPS ACRS THE MICHIGAN/FAR NRN INDIANA COUNTIES THIS EVENING IN ANTICIPATION OF THE LAST ROUND OF LAKE EFFECT PCPN. ADDITIONAL SNOWFALL AMOUNTS WILL RANGE FROM A TRACE SOUTH (FLURRIES) TO 1 TO 2 INCHES ACRS FAR NRN INDIANA/SOUTHERN MICHIGAN. SINCE POPS WILL BE RAISED TO LIKELY ACRS THE NORTH...WILL EXTEND THE LAKE EFFECT SNOW ADVISORY FOR BERRIEN AND CASS COUNTIES TO 06Z...OR 1 AM EDT. TOTAL SNOW ACCUMULATION WILL RANGE BETWEEN 4 AND 7 INCHES ACRS THE ADVISORY AREA. AS FOR TEMPS TODAY...THEY WILL BE TRICKY AS COLD ARCTIC AIR WILL CAUSE TEMPS TO TUMBLE INTO THE 10 TO 15 DEGREE RANGE BY MID MORNING ACRS THE SWRN CWFA. TEMPS WILL REMAIN SLIGHTLY WARMER DOWNWIND OF LAKE MICHIGAN. THEREAFTER...ONLY A SLIGHT DIURNAL RISE IS EXPECTED THIS AFTN. FOR TONIGHT...LOWS WILL DIP INTO THE SINGLE DIGITS ACRS MOST OF THE REGION...EXCEPT FOR LOCATIONS NEAR THE LAKE. WHERE TEMPS WILL REMAIN IN THE 10 TO 15 DEGREE RANGE. LONG TERM... WEDNESDAY THROUGH MONDAY. THE ARCTIC EXPRESS CONTINUES TO BE THE WX FOCUS THROUGH THE FORECAST PERIOD. BELOW NORMAL TEMPERATURES AND PERIODS OF SNOW WILL BE THE RULE. FORECAST MODELS HAVE BEEN RELATIVELY STABLE IN SOLUTION...SO NO REASON TO MAKE BIG CHANGES TO ONGOING FORECAST. AS POLAR VORTEX GRADUALLY SINKS SOUTH INTO SOUTHERN CANADA...SURGES OF COLDER AIR CONTINUE TO REINFORCE THE ALREADY BELOW NORMAL CONDITIONS. THE COLD AIR CONTINUES TO CAUSE LAKE EFFECT SNOW SHOWERS TO DEVELOP WHEN THE WIND DIRECTION IS FAVORABLE. WITH THE UPPER LOW IN THE AREA...A VERY UNSETTLED WEATHER PATTERN CONTINUES AS SPOKES OF ENERGY ROTATE AROUND THE UPPER LOW. THEREFORE...MOST PERIODS HAVE A MENTION OF SNOW THROUGH THE FORECAST PERIOD. COLDEST AIR OF THE SEASON IS FORECAST INTO THE AREA THIS WEEKEND. WITH FRESH SNOW COVER AND STRONG CAA...MIN TEMPS COULD APPROACH OR FALL BELOW ZERO AND MAXS WOULD STRUGGLE TO CLIMB OUT OF THE SINGLE DIGITS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...SNOW AND BLOWING SNOW ADVISORY UNTIL 1 AM EST WEDNESDAY FOR INZ004>009-016>018. MI...SNOW AND BLOWING SNOW ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MIZ079>081. LAKE EFFECT SNOW WARNING UNTIL 1 AM EST WEDNESDAY FOR MIZ077-078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR LMZ043-046. && $$ SHORT TERM...SKIPPER AVIATION...HICKMAN LONG TERM....EDDY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 635 AM EST TUE JAN 30 2007 .AVIATION... AN UPR LVL VORT MAX AND ASSOCD SFC TROF WILL MOVE ACRS NRN INDIANA BETWEEN 12Z AND 18Z. LATEST KIWX RADAR INDICATED A LOW LVL MESOSCALE LAKE MICHIGAN VORTICITY MOVING INTO SOUTHWEST LOWER MICHIGAN AND FAR NORTHWEST INDIANA. THIS FEATURE WILL LIKELY DROP VSBYS TO A 1/2SM MILE FOR A COUPLE HOURS AT KSBN. THEREAFTER...ONLY SCATTERED SNOW SHOWERS AND MVFR CONDITIONS CAN BE EXPECTED AT KSBN UNTIL THIS EVENING. FOR KFWA...MVFR CIGS/VSBYS CAN BE EXPECTED THROUGH 15Z...THEN VSBYS WILL IMPROVE TO P6SM WITH ONLY A SCATTERING OF LIGHT SNOW SHOWERS IN THE VICINITY. FOR TONIGHT...ANOTHER SFC TROF AND LAST SURGE OF LAKE EFFECT SNOW IS FORECAST TO MOVE ACRS THE KSBN TAF SITE BETWEEN 00Z AND 06Z. WILL INCLUDE A PERIOD OF IFR CONDITIONS DURING THIS TIME FRAME. LAKE EFFECT SNOW SHOWERS WILL DIMINISH TO FLURRIES AND WILL PUSH NORTH INTO MICHIGAN AFTER 06Z. SFC HIGH PRESSURE IS FORECAST TO BUILD INTO THE REGION AFTER 12Z WEDNESDAY WITH VFR CONDITIONS RETURNING TO THE REGION. && .PREV DISCUSSION... /ISSUED 404 AM EST TUE JAN 30 2007/ SHORT TERM... TODAY AND TONIGHT. WILL BE USING THE LATEST RUC AND 00Z NAM-WRF FOR THE SHORT TERM FCST AS THEY SEEM TO HAVE A DECENT HANDLE ON THE SYNOPTIC AND MESOSCALE SITUATION. SFC ANALYSIS AT 08Z DEPICTED A CLIPPER SYSTEM ACRS THE WRN GREAT LAKES REGION. THE MAIN SFC LOW WAS LOCATED OVER WRN MICHIGAN WITH A COLD FRONT TRAILING FROM THE LOW INTO WRN INDIANA...THEN BACK INTO THE SRN PLAINS. THE MAIN SFC LOW AND COLD FRONT WILL MOVE RAPIDLY EAST THIS MORNING AWAY FROM THE REGION. KIWX RADAR WAS SHOWING A DECENT SIZE OF SNOW OUT AHEAD OF THIS FRONT OVER THE ERN TWO THIRDS OF THE FCST AREA. SOME OF THE SNOW WAS LOCALLY HEAVY IN SPOTS AS INDICATED BY THE 08Z KFWA OBSERVATION WHICH REPORTED AN INCH IN ONE HOUR. THIS SNOW WILL QUICKLY MOVE EAST EARLY THIS MORNING...AND SHOULD BE EXISTING THE ERN FCST AREA BETWEEN 5 AND 6 AM. TO THE WEST...AN UPR LVL VORT MAX WAS LOCATED OVER NRN IL. THIS FEATURE WILL SWEEP ACRS NRN INDIANA BETWEEN 12Z AND 18Z...BRINING A ROUND OF SNOW SHOWERS. TO ADD TO THE MIX...LAKE EFFECT SNOW SHOWERS WILL DEVELOP AFTER 15Z AS THE MEAN LOW LVL FLOW VEERS TO A 290 DIRECTION. MODELS INDICATE THERE COULD BE A BREAK IN THE WIDESPREAD PCPN...EXCEPT IN THE LAKE EFFECT REGIONS OF MICHIGAN AND FAR NRN INDIANA...BY THIS AFTN...BUT WILL NOT TRY TO TIME THIS ATTM. GUSTY WEST TO NORTHWEST WINDS OF 25 TO 30 MPH WILL CAUSE SOME BLOWING OF SNOW...AND HAVE ADDED THIS TO THE ZONES ACRS NRN INDIANA...SRN MICHIGAN AND FAR NORTHWEST OHIO. SNOWFALL AMOUNTS TODAY WILL RANGE FROM AROUND A HALF INCH SOUTH TO 4 INCHES IN BERRIEN AND CASS COUNTIES...WHERE A LAKE EFFECT SNOW ADVISORY WILL REMAIN IN EFFECT. FOR TONIGHT...MEAN LOW LVL FLOW WILL VEER A LITTLE MORE TO THE NORTHWEST...ABOUT 300 DEGREES. ONE LAST SURGE OF LAKE EFFECT SNOW IS EXPECTED DOWNWIND OF LAKE MICHIGAN DURING THE EVENING. THEREAFTER...INVERSION HEIGHTS WILL BEGIN TO LOWER AND DRIER AIR WILL GRADUALLY WORK INTO THE REGION FROM THE WEST TO CAUSE THE LAKE EFFECT PCPN TO DWINDLE CONSIDERABLY AFTER 06Z WEDNESDAY. WILL RAISE POPS ACRS THE MICHIGAN/FAR NRN INDIANA COUNTIES THIS EVENING IN ANTICIPATION OF THE LAST ROUND OF LAKE EFFECT PCPN. ADDITIONAL SNOWFALL AMOUNTS WILL RANGE FROM A TRACE SOUTH (FLURRIES) TO 1 TO 2 INCHES ACRS FAR NRN INDIANA/SOUTHERN MICHIGAN. SINCE POPS WILL BE RAISED TO LIKELY ACRS THE NORTH...WILL EXTEND THE LAKE EFFECT SNOW ADVISORY FOR BERRIEN AND CASS COUNTIES TO 06Z...OR 1 AM EDT. TOTAL SNOW ACCUMULATION WILL RANGE BETWEEN 4 AND 7 INCHES ACRS THE ADVISORY AREA. AS FOR TEMPS TODAY...THEY WILL BE TRICKY AS COLD ARCTIC AIR WILL CAUSE TEMPS TO TUMBLE INTO THE 10 TO 15 DEGREE RANGE BY MID MORNING ACRS THE SWRN CWFA. TEMPS WILL REMAIN SLIGHTLY WARMER DOWNWIND OF LAKE MICHIGAN. THEREAFTER...ONLY A SLIGHT DIURNAL RISE IS EXPECTED THIS AFTN. FOR TONIGHT...LOWS WILL DIP INTO THE SINGLE DIGITS ACRS MOST OF THE REGION...EXCEPT FOR LOCATIONS NEAR THE LAKE. WHERE TEMPS WILL REMAIN IN THE 10 TO 15 DEGREE RANGE. LONG TERM... WEDNESDAY THROUGH MONDAY. THE ARCTIC EXPRESS CONTINUES TO BE THE WX FOCUS THROUGH THE FORECAST PERIOD. BELOW NORMAL TEMPERATURES AND PERIODS OF SNOW WILL BE THE RULE. FORECAST MODELS HAVE BEEN RELATIVELY STABLE IN SOLUTION...SO NO REASON TO MAKE BIG CHANGES TO ONGOING FORECAST. AS POLAR VORTEX GRADUALLY SINKS SOUTH INTO SOUTHERN CANADA...SURGES OF COLDER AIR CONTINUE TO REINFORCE THE ALREADY BELOW NORMAL CONDITIONS. THE COLD AIR CONTINUES TO CAUSE LAKE EFFECT SNOW SHOWERS TO DEVELOP WHEN THE WIND DIRECTION IS FAVORABLE. WITH THE UPPER LOW IN THE AREA...A VERY UNSETTLED WEATHER PATTERN CONTINUES AS SPOKES OF ENERGY ROTATE AROUND THE UPPER LOW. THEREFORE...MOST PERIODS HAVE A MENTION OF SNOW THROUGH THE FORECAST PERIOD. COLDEST AIR OF THE SEASON IS FORECAST INTO THE AREA THIS WEEKEND. WITH FRESH SNOW COVER AND STRONG CAA...MIN TEMPS COULD APPROACH OR FALL BELOW ZERO AND MAXS WOULD STRUGGLE TO CLIMB OUT OF THE SINGLE DIGITS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MIZ077- 078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR LMZ043-046. && $$ SHORT TERM/AVIATION...HICKMAN LONG TERM....EDDY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 404 AM EST TUE JAN 30 2007 .SHORT TERM... TODAY AND TONIGHT. WILL BE USING THE LATEST RUC AND 00Z NAM-WRF FOR THE SHORT TERM FCST AS THEY SEEM TO HAVE A DECENT HANDLE ON THE SYNOPTIC AND MESOSCALE SITUATION. SFC ANALYSIS AT 08Z DEPICTED A CLIPPER SYSTEM ACRS THE WRN GREAT LAKES REGION. THE MAIN SFC LOW WAS LOCATED OVER WRN MICHIGAN WITH A COLD FRONT TRAILING FROM THE LOW INTO WRN INDIANA...THEN BACK INTO THE SRN PLAINS. THE MAIN SFC LOW AND COLD FRONT WILL MOVE RAPIDLY EAST THIS MORNING AWAY FROM THE REGION. KIWX RADAR WAS SHOWING A DECENT SIZE OF SNOW OUT AHEAD OF THIS FRONT OVER THE ERN TWO THIRDS OF THE FCST AREA. SOME OF THE SNOW WAS LOCALLY HEAVY IN SPOTS AS INDICATED BY THE 08Z KFWA OBSERVATION WHICH REPORTED AN INCH IN ONE HOUR. THIS SNOW WILL QUICKLY MOVE EAST EARLY THIS MORNING...AND SHOULD BE EXISTING THE ERN FCST AREA BETWEEN 5 AND 6 AM. TO THE WEST...AN UPR LVL VORT MAX WAS LOCATED OVER NRN IL. THIS FEATURE WILL SWEEP ACRS NRN INDIANA BETWEEN 12Z AND 18Z...BRINING A ROUND OF SNOW SHOWERS. TO ADD TO THE MIX...LAKE EFFECT SNOW SHOWERS WILL DEVELOP AFTER 15Z AS THE MEAN LOW LVL FLOW VEERS TO A 290 DIRECTION. MODELS INDICATE THERE COULD BE A BREAK IN THE WIDESPREAD PCPN...EXCEPT IN THE LAKE EFFECT REGIONS OF MICHIGAN AND FAR NRN INDIANA...BY THIS AFTN...BUT WILL NOT TRY TO TIME THIS ATTM. GUSTY WEST TO NORTHWEST WINDS OF 25 TO 30 MPH WILL CAUSE SOME BLOWING OF SNOW...AND HAVE ADDED THIS TO THE ZONES ACRS NRN INDIANA...SRN MICHIGAN AND FAR NORTHWEST OHIO. SNOWFALL AMOUNTS TODAY WILL RANGE FROM AROUND A HALF INCH SOUTH TO 4 INCHES IN BERRIEN AND CASS COUNTIES...WHERE A LAKE EFFECT SNOW ADVISORY WILL REMAIN IN EFFECT. FOR TONIGHT...MEAN LOW LVL FLOW WILL VEER A LITTLE MORE TO THE NORTHWEST...ABOUT 300 DEGREES. ONE LAST SURGE OF LAKE EFFECT SNOW IS EXPECTED DOWNWIND OF LAKE MICHIGAN DURING THE EVENING. THEREAFTER...INVERSION HEIGHTS WILL BEGIN TO LOWER AND DRIER AIR WILL GRADUALLY WORK INTO THE REGION FROM THE WEST TO CAUSE THE LAKE EFFECT PCPN TO DWINDLE CONSIDERABLY AFTER 06Z WEDNESDAY. WILL RAISE POPS ACRS THE MICHIGAN/FAR NRN INDIANA COUNTIES THIS EVENING IN ANTICIPATION OF THE LAST ROUND OF LAKE EFFECT PCPN. ADDITIONAL SNOWFALL AMOUNTS WILL RANGE FROM A TRACE SOUTH (FLURRIES) TO 1 TO 2 INCHES ACRS FAR NRN INDIANA/SOUTHERN MICHIGAN. SINCE POPS WILL BE RAISED TO LIKELY ACRS THE NORTH...WILL EXTEND THE LAKE EFFECT SNOW ADVISORY FOR BERRIEN AND CASS COUNTIES TO 06Z...OR 1 AM EDT. TOTAL SNOW ACCUMULATION WILL RANGE BETWEEN 4 AND 7 INCHES ACRS THE ADVISORY AREA. AS FOR TEMPS TODAY...THEY WILL BE TRICKY AS COLD ARCTIC AIR WILL CAUSE TEMPS TO TUMBLE INTO THE 10 TO 15 DEGREE RANGE BY MID MORNING ACRS THE SWRN CWFA. TEMPS WILL REMAIN SLIGHTLY WARMER DOWNWIND OF LAKE MICHIGAN. THEREAFTER...ONLY A SLIGHT DIURNAL RISE IS EXPECTED THIS AFTN. FOR TONIGHT...LOWS WILL DIP INTO THE SINGLE DIGITS ACRS MOST OF THE REGION...EXCEPT FOR LOCATIONS NEAR THE LAKE. WHERE TEMPS WILL REMAIN IN THE 10 TO 15 DEGREE RANGE. && .LONG TERM... WEDNESDAY THROUGH MONDAY. THE ARCTIC EXPRESS CONTINUES TO BE THE WX FOCUS THROUGH THE FORECAST PERIOD. BELOW NORMAL TEMPERATURES AND PERIODS OF SNOW WILL BE THE RULE. FORECAST MODELS HAVE BEEN RELATIVELY STABLE IN SOLUTION...SO NO REASON TO MAKE BIG CHANGES TO ONGOING FORECAST. AS POLAR VORTEX GRADUALLY SINKS SOUTH INTO SOUTHERN CANADA...SURGES OF COLDER AIR CONTINUE TO REINFORCE THE ALREADY BELOW NORMAL CONDITIONS. THE COLD AIR CONTINUES TO CAUSE LAKE EFFECT SNOW SHOWERS TO DEVELOP WHEN THE WIND DIRECTION IS FAVORABLE. WITH THE UPPER LOW IN THE AREA...A VERY UNSETTLED WEATHER PATTERN CONTINUES AS SPOKES OF ENERGY ROTATE AROUND THE UPPER LOW. THEREFORE...MOST PERIODS HAVE A MENTION OF SNOW THROUGH THE FORECAST PERIOD. COLDEST AIR OF THE SEASON IS FORECAST INTO THE AREA THIS WEEKEND. WITH FRESH SNOW COVER AND STRONG CAA...MIN TEMPS COULD APPROACH OR FALL BELOW ZERO AND MAXS WOULD STRUGGLE TO CLIMB OUT OF THE SINGLE DIGITS. && .PREV DISCUSSION... /ISSUED 1229 AM EST TUE JAN 30 2007/ AVIATION... A FAST MOVING CLIPPER SYSTEM WILL PUSH ACRS THE WESTERN GREAT LAKES THROUGH 12Z...THEN IT WILL MOVE EAST INTO THE ERN GREAT LAKES BY 18Z. SVRL UPR LVL WX DISTURBANCES ALOFT WILL ACCOMPANY THIS SYSTEM OVERNIGHT. THE COMBINATION OF UPR LVL LIFT AND LOW LVL CONVERGENCE AHEAD OF A COLD FRONT WILL BRING WIDESPREAD SNOW TO NRN INDIANA ANS SUBSEQUENT TAF SITES THROUGH AT LEAST 15Z. THEREAFTER...COLD AIR FLOWING OVER THE RELATIVELY WARM WATERS OF LAKE MICHIGAN WILL GENERATE LAKE EFFECT SNOW SHOWERS...WHICH SHOULD MAINLY AFFECT THE KSBN TAF SITE. MVFR/IFR CONDITIONS CAN BE EXPECTED THROUGH AT LEAST 15Z...WITH MVFR AND POSSIBLE IFR CONDITIONS BEYOND 15Z WITH LAKE EFFECT SNOW SHOWERS. WIND GUSTS AROUND 25 KNOTS CAN BE EXPECTED IN THE WAKE OF THE COLD FRONT...WHICH WILL CAUSE SOME BLOWING SNOW TO OCCUR AT KSBN BEYOND 12Z. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MIZ077- 078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR LMZ043-046. && $$ SHORT TERM/AVIATION...HICKMAN LONG TERM....EDDY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 945 PM EST WED JAN 31 2007 .EVENING UPDATE DISCUSSION: LATEST IR SATELLITE LOOP IS SHOWING SOME ENHANCEMENT IN THE CLOUD ELEMENTS OVER CENTRAL AND NORTHERN AR AND NRN AL ...LOOKING AT THE RADAR TRENDS THAT AREA...THEY ARE SHOWING SOME INCREASE IN COVERAGE TOO. BOTH THE CLOUDS AND PCPN ARE MOVING TO THE NORTHEAST TOWARDS SRN KY. A PRELIMINARY LOOK AT THE NEW 00Z NAM MODEL DATA IS NOT AS PROMISING FOR SNOWFALL. THE AIR ALOFT WAS INITIALLY QUITE DRY TODAY AND IF THE AIR DOESN`T BECOME SUFFICIENTLY SATURATED IN THE LOWER LEVELS... ANY PRECIP THAT DOES FALL WILL EVAPORATE BEFORE REACHING THE GROUND. THE 18Z GFS DID SHOW SUFFICIENT SATURATION AND ENOUGH SYNOPTIC LIFT FOR AN INCH OR TWO OF SNOWFALL ESPECIALLY DURING THE 10Z-18Z TIME FRAME ACROSS PORTIONS OF SOUTHERN KENTUCKY. THIS MATCHES WELL WITH OUR SNOW ADVISORY ACROSS THE SOUTHERN PORTION OF THE FA. THE LATEST RUC40 RH TRENDS SHOW A MAJOR INCREASE IN LOW LEVEL RH SW TO NE ACROSS MOST OF THE REGION OVERNIGHT...THIS TOO WUD SUPPORT THE POTENTIAL FOR MEASURABLE SNOW LATER TONIGHT. BEFORE MAKING ANY MAJOR CHANGES...WE NEED TO LOOK AT THE FULL SUITE OF 00Z MODEL RUNS...PLUS CHECK WITH THE NEXT HPC SNOW FCSTS AND CONSIDER THEIR ANALYSIS TOO. COORDINATED WITH JKL AND THEY WERE PLANNING TO LEAVE THEIR ADVISORY INTACT. AT THIS TIME WE ARE NOT MAKING ANY CHANGES IN THE CURRENT FCST. --21 ....PREVIOUS FCST DISCUSSIONS FOR TODAY ARE BELOW:... .AVIATION DISCUSSION (00Z) FCSTS... GENERAL AC CIGS 10 THSD OR ABOVE TO START OUT TAFS...WITH GRADUAL INCREASE IN LOW AND MID LEVEL RH DURING THE NIGHT WHICH WILL EVENTUALLY LEAD TO SOME LIGHT SNOW...RIGHT NOW IT LOOKS AS THOUGH THE MAIN BAND OF LIGHT SNOW WILL BE ACROSS SRN KY...SO WILL EVENTUALLY LOWER CIG AND VSBY CONDITIONS TO IFR FOR BWG AND MVFR FOR LEX AND SDF. STILL SOME DOUBT ABOUT HOW MUCH SNOW WE WILL GET. WE WILL HAVE TO CONTINUE TO MONITOR WX AND MODEL TRENDS CLOSELY. --21 .SHORT TERM... (TONIGHT THROUGH THURSDAY NIGHT)... ...SNOW ADVISORY ACROSS SOUTHERN KY AND SOUTHERN BLUEGRASS... SHORT-TERM FORECAST REVOLVES AROUND SOUTHERN STREAM SYSTEMS AND SNOW ACCUMULATION CHANCES WITH EACH. TONIGHT-MIDDAY THURS... HIGH PRESSURE OVERHEAD WILL MOVE OFF TO THE EAST TONIGHT...AS AN INVERTED TROUGH OVER THE GULF MOVES FROM TEXAS TOWARD THE CAROLINAS. MOISTURE IS NOT TOO IMPRESSIVE WITH THIS SYSTEM...HOWEVER THE DYNAMICS ARE STRONG. SOUTHERN JET OF ROUGHLY 150 KTS OR SO WILL BE OVERHEAD...WITH THE CWA UNDER THE LEFT-EXIT REGION AFTER MIDNIGHT. AMPLE LIFT WILL THUS HELP SNOW DEVELOP AFTER MIDNIGHT TOWARD MORNING. AREA SOUNDINGS INDICATE THE BEST CHANCE OF SNOW WILL BE BETWEEN 10-17Z. SOME HEAVIER SNOW MAY MIX IN AT TIMES GIVEN UPSTREAM REPORTS AND PROGGED -EPV ALOFT CO-LOCATED WITH MAX OMEGAS. BUT GIVEN THE LACK OF MOISTURE AND SPEED OF SYSTEM...WILL NOT GET CARRIED AWAY WITH SNOW AMOUNTS. THUS...WILL ISSUE A SNOW ADVSY FROM 1-2 INCHES POSSIBLE MAINLY SE OF A LINE FROM MORGANTOWN TO LEBANON. MAY BE A BIT TOO FAR NORTH WITH THE ADVY GIVEN THE NAM 18Z RUN...BUT 12Z GFS/NAM AND HPC INDICATE FAR SRN KY COULD GET THESE ACCUMULATING SNOWS. THE BIGGER PROBLEM WILL BE TIMING NOT THE ACTUAL ACCUMS. GIVEN TIME OF DAY (NEAR MORNING COMMUTE TIME) FELT IT WAS WORTH BUMPING UP THE SPS TO AN ADVSY. WILL KEEP THE HIGHER SNOW AMOUNTS ACROSS THE FAR SERN CWA. ELSEWHERE...WILL CONTINUE SPS FOR AROUND AN INCH OF ACCUMULATION. FEEL THAT THE THREAT IS MINIMIZED ACROSS CENTRAL KY...HOWEVER A BETTER CHANCE MAY EXIST NEAR THE OHIO RIVER WITH THE DEFORMATION ZONE DEVELOPING FROM KC TO WICHITA. THIS SHOULD ALIGN SOMEWHERE ACROSS OUR NRN CWA...POSSIBLY NEAR THE KY/IN BORDER. SNOWFALL AMOUNTS WITHIN THE SPS AREA WILL BE HIGHER IN THE DEFORMATION ZONE...BUT IT IS STILL EXPECTED TO BE LIGHT SNOW ONLY. MAIN PRECIP WILL END BY MIDDAY (ADVY ENDS AT 18Z)...THOUGH LOW CLOUDS MAY CONTINUE THROUGH THE AFTERNOON. WITH THIS...EVEN A FEW LIGHT SHOWERS/FLURRIES MAY CONTINUE INTO THE AFTERNOON HOURS. SFC TEMPS MAY INCREASE ENOUGH ACROSS THE SOUTH WHERE A CHANGEOVER TO LIGHT RAIN/DRIZZLE MAY OCCUR. HAVE A RAIN/SNOW MIX ACROSS THE SOUTH FOR NOW. MIDDAY THURS-OVERNIGHT THURS... SECOND WAVE IN SOUTHERN STREAM WILL QUICKLY MOVE TOWARD THE EAST COAST RIGHT ON THE HEELS OF THE FIRST SYSTEM. THIS SYSTEM IS MORE OF A CLOSED SFC LOW AS OPPOSED TO A SFC TROUGH...AND IS COMBINED WITH EVEN STRONGER DYNAMICS ALOFT. HOWEVER MOISTURE IS EVEN MORE LACKING...BUT THE DYNAMICS ARE THERE FOR YET ANOTHER POSSIBLE ADVSY SITUATION THRS NIGHT-FRI MORN. WILL LOOK MORE AT IT TONIGHT AND TOMORROW MORNING...BUT WILL HIT IT HARD IN THE HWO. THIS LATTER SYSTEM WOULD BE MORE OF A CWA-WIDE EVENT TOO. WILL CONTINUE WITH ONE-INCH ACCUMS FOR NOW. AS FAR AS TEMPS GO THROUGH THE PERIOD...WILL ONLY DROP ABOUT 5 DEGREES TONIGHT BEFORE CLOUDS INCREASE OVERNIGHT AND KEEP OUR TEMPS STEADY. TOMORROW...WILL LIKELY HEAT UP...ESPECIALLY IN THE AFTERNOON. HOWEVER WILL UNDERCUT RUC13/GFS AS I FEEL THESE ARE RUNNING A BIT TOO HIGH. LOW TO MID 30S LOOK LIKELY FOR HIGHS THURS. AL .LONG TERM (FRI THRU WED)... FRI THRU SAT NGT... SHRTWV TROF WILL BE DROPPING DOWN INTO THE UPR MS VLY/WRN GREAT LAKES AT THE START OF THE PERIOD WITH MORE ENERGY ROUNDING THE BASE OF THE UPR LEVEL BROAD TROF TOWARD THE LOWER MS VLY. THIS ELONGATED AXIS OF HIER VORTICITY BECOMES INCREASINGLY SHEARED AS IT MOVES THRU OUR FA FRI WITH AFOREMENTIONED SHRTWV MOVG WELL TO OUR NORTH...ACRS THE GREAT LAKES. AFTERWARD...WE REMAIN IN A BROAD TROF THRU THE END OF THE PERIOD WITH ANOTHER IMPLSE APPROACHING OUR FA SAT NIGHT. ASSOCIATED CDFNT WILL MOVE THRU FRI...WITH A RIDGE OF HI PRES IN ITS WAKE FOR FRI NIGHT AND MUCH OF SAT. WILL CONTINUE CHC POPS FOR LIGHT SNOW PRECEDING FRONT...MAINLY IN THE FIRST HALF OF THE DAY. A REINFORCING SHOT OF COLD AIR...ASSOCIATED WITH AFOREMENTIONED IMPULSE...WILL LIKELY MOVE THRU OUR FA SAT NIGHT. WILL DOWNPLAY THE NAM/WRF DEEPER MOISTURE PRECEDING AND WITH FRONT AND CONT A PARTLY CLOUDY FCST...CLOSER TO THE GFS. 11 SUN THRU WED... VERY COLD AND MAINLY DRY THRU THIS PERIOD. BROAD UPR LEVEL TROF WILL RESIDE ACRS THE OH VLY THRU LATE MON WITH AXIS SHIFTING INTO NEW ENGLAND TUE AND OFF THE NEW ENGLAND COAST WED. AFTER AXIS PASSAGE MON...OUR REGION WILL BE IN COLD NW FLO THRU THE END OF THE PERIOD. 00Z MEDIUM RANGE MODELS AND 12Z GFS ARE SIMILAR WITH SHOWING A FAST MOVG CLIPPER SYS/WEAK SFC LO MOVING INTO THE LOWER OH VLY SUN NGT AND EXITING MON MORNING. THIS APPEARS TO BE OUR BEST CHC FOR A MEASURABLE SNOW DURING THIS PERIOD WITH POSSIBLY A 1 TO 3 INCH DRY FLUFFY SNOW ACRS OUR FORECAST AREA(FA)...MOSTLY OVER OUR NRN/ERN FA. TEMPS WILL BE UNSEASONALLY COLD...ESPECIALLY AFTER CLIPPER PASSAGE MON WITH SINGLE DIGIT READINGS MON AND TUE NGT AS ARCTIC HI PRES BUILDS INTO AND OVER THE LOWER OH VLY. AFTER POPULATING WITH HPC GRIDS FOR TUE AND WED...WILL MAKE THE FOLLOWING CHGS TO TEMP GRIDS. WILL RAISE SUN NGT MINS CONSIDERABLY TO ACCOUNT FOR INCREASING CLOUDS/A BRIEF PERIOD OF WARM ADVECTION AHEAD OF CLIPPER. WILL RAISE MAXS MON A FEW DEGREES CLOSER TO ENSEMBLE MEANS AND HPC AND TO AGREE BETTER WITH OUR NEIGHBORS. IF WE GET AN INCH OR TWO OF SNOW COVER BEFORE THIS PERIOD AND ON SUN NGT AS WELL...THESE TEMPS WILL NEED TO BE ADJUSTED DOWN...IN OTHER WORDS...BELOW ZERO FOR MINS BEGINNING MON NGT. DK && .AVIATION (18Z TAFS)... VFR CONDITIONS WILL CONTINUE FOR THE SDF...LEX AND BWG TAF SITES THROUGH THE FIRST SIX HOURS OF THIS TAF FORECAST. HIGH PRESSURE OVERHEAD WILL KEEP MOSTLY SUNNY CONDITIONS WITH LIGHT VARIABLE TO SOUTH WINDS...5 TO 10 MPH. MID-LEVEL DECK WILL FILTER IN FROM THE WEST FROM 21-00Z THIS EVENING. CIGS SHOULD STAY VFR UNTIL 06Z FOR BWG...AND BY 10Z AND 12Z FOR SDF AND LEX RESPECTIVELY...WHERE LIGHT SNOW MAY REDUCE VISBYS DOWN TO ONE MILE OR SO AT TIMES. ONSET OF -SN WILL BE LIGHT DUE TO LOWER LEVELS NOT BEING FULLY SATURATED. MAY CARRY A TEMPO FOR HEAVIER SNOW FOR THE BWG TAF ROUGHLY FROM 10-14Z. ONCE SNOW BEGINS...MAY TREND TOWARD LOWER END MVFR CIGS AND IFR VISBYS WITH THE HEAVIER SNOW SOMETIME BETWEEN 12-18Z FOR ALL TAF SITES. AL && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 5 AM EST /4 AM CST/ TO 1 PM EST /12 PM CST/ THURSDAY FOR KYZ062>066-070>078-081-082. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 624 PM EST WED JAN 31 2007 .AVIATION DISCUSSION (00Z) FCSTS... GENERAL AC CIGS 10 THSD OR ABOVE TO START OUT TAFS...WITH GRADUAL INCREASE IN LOW AND MID LEVEL RH DURING THE NIGHT WHICH WILL EVENTUALLY LEAD TO SOME LIGHT SNOW...RIGHT NOW IT LOOKS AS THOUGH THE MAIN BAND OF LIGHT SNOW WILL BE ACROSS SRN KY...SO WILL EVENTUALLY LOWER CIG AND VSBY CONDITIONS TO IFR FOR BWG AND MVFR FOR LEX AND SDF. STILL SOME DOUBT ABOUT HOW MUCH SNOW WE WILL GET. WE WILL HAVE TO CONTINUE TO MONITOR WX AND MODEL TRENDS CLOSELY. --21 .SHORT TERM... (TONIGHT THROUGH THURSDAY NIGHT)... ...SNOW ADVISORY ACROSS SOUTHERN KY AND SOUTHERN BLUEGRASS... SHORT-TERM FORECAST REVOLVES AROUND SOUTHERN STREAM SYSTEMS AND SNOW ACCUMULATION CHANCES WITH EACH. TONIGHT-MIDDAY THURS... HIGH PRESSURE OVERHEAD WILL MOVE OFF TO THE EAST TONIGHT...AS AN INVERTED TROUGH OVER THE GULF MOVES FROM TEXAS TOWARD THE CAROLINAS. MOISTURE IS NOT TOO IMPRESSIVE WITH THIS SYSTEM...HOWEVER THE DYNAMICS ARE STRONG. SOUTHERN JET OF ROUGHLY 150 KTS OR SO WILL BE OVERHEAD...WITH THE CWA UNDER THE LEFT-EXIT REGION AFTER MIDNIGHT. AMPLE LIFT WILL THUS HELP SNOW DEVELOP AFTER MIDNIGHT TOWARD MORNING. AREA SOUNDINGS INDICATE THE BEST CHANCE OF SNOW WILL BE BETWEEN 10-17Z. SOME HEAVIER SNOW MAY MIX IN AT TIMES GIVEN UPSTREAM REPORTS AND PROGGED -EPV ALOFT CO-LOCATED WITH MAX OMEGAS. BUT GIVEN THE LACK OF MOISTURE AND SPEED OF SYSTEM...WILL NOT GET CARRIED AWAY WITH SNOW AMOUNTS. THUS...WILL ISSUE A SNOW ADVSY FROM 1-2 INCHES POSSIBLE MAINLY SE OF A LINE FROM MORGANTOWN TO LEBANON. MAY BE A BIT TOO FAR NORTH WITH THE ADVY GIVEN THE NAM 18Z RUN...BUT 12Z GFS/NAM AND HPC INDICATE FAR SRN KY COULD GET THESE ACCUMULATING SNOWS. THE BIGGER PROBLEM WILL BE TIMING NOT THE ACTUAL ACCUMS. GIVEN TIME OF DAY (NEAR MORNING COMMUTE TIME) FELT IT WAS WORTH BUMPING UP THE SPS TO AN ADVSY. WILL KEEP THE HIGHER SNOW AMOUNTS ACROSS THE FAR SERN CWA. ELSEWHERE...WILL CONTINUE SPS FOR AROUND AN INCH OF ACCUMULATION. FEEL THAT THE THREAT IS MINIMIZED ACROSS CENTRAL KY...HOWEVER A BETTER CHANCE MAY EXIST NEAR THE OHIO RIVER WITH THE DEFORMATION ZONE DEVELOPING FROM KC TO WICHITA. THIS SHOULD ALIGN SOMEWHERE ACROSS OUR NRN CWA...POSSIBLY NEAR THE KY/IN BORDER. SNOWFALL AMOUNTS WITHIN THE SPS AREA WILL BE HIGHER IN THE DEFORMATION ZONE...BUT IT IS STILL EXPECTED TO BE LIGHT SNOW ONLY. MAIN PRECIP WILL END BY MIDDAY (ADVY ENDS AT 18Z)...THOUGH LOW CLOUDS MAY CONTINUE THROUGH THE AFTERNOON. WITH THIS...EVEN A FEW LIGHT SHOWERS/FLURRIES MAY CONTINUE INTO THE AFTERNOON HOURS. SFC TEMPS MAY INCREASE ENOUGH ACROSS THE SOUTH WHERE A CHANGEOVER TO LIGHT RAIN/DRIZZLE MAY OCCUR. HAVE A RAIN/SNOW MIX ACROSS THE SOUTH FOR NOW. MIDDAY THURS-OVERNIGHT THURS... SECOND WAVE IN SOUTHERN STREAM WILL QUICKLY MOVE TOWARD THE EAST COAST RIGHT ON THE HEELS OF THE FIRST SYSTEM. THIS SYSTEM IS MORE OF A CLOSED SFC LOW AS OPPOSED TO A SFC TROUGH...AND IS COMBINED WITH EVEN STRONGER DYNAMICS ALOFT. HOWEVER MOISTURE IS EVEN MORE LACKING...BUT THE DYNAMICS ARE THERE FOR YET ANOTHER POSSIBLE ADVSY SITUATION THRS NIGHT-FRI MORN. WILL LOOK MORE AT IT TONIGHT AND TOMORROW MORNING...BUT WILL HIT IT HARD IN THE HWO. THIS LATTER SYSTEM WOULD BE MORE OF A CWA-WIDE EVENT TOO. WILL CONTINUE WITH ONE-INCH ACCUMS FOR NOW. AS FAR AS TEMPS GO THROUGH THE PERIOD...WILL ONLY DROP ABOUT 5 DEGREES TONIGHT BEFORE CLOUDS INCREASE OVERNIGHT AND KEEP OUR TEMPS STEADY. TOMORROW...WILL LIKELY HEAT UP...ESPECIALLY IN THE AFTERNOON. HOWEVER WILL UNDERCUT RUC13/GFS AS I FEEL THESE ARE RUNNING A BIT TOO HIGH. LOW TO MID 30S LOOK LIKELY FOR HIGHS THURS. AL .LONG TERM (FRI THRU WED)... FRI THRU SAT NGT... SHRTWV TROF WILL BE DROPPING DOWN INTO THE UPR MS VLY/WRN GREAT LAKES AT THE START OF THE PERIOD WITH MORE ENERGY ROUNDING THE BASE OF THE UPR LEVEL BROAD TROF TOWARD THE LOWER MS VLY. THIS ELONGATED AXIS OF HIER VORTICITY BECOMES INCREASINGLY SHEARED AS IT MOVES THRU OUR FA FRI WITH AFOREMENTIONED SHRTWV MOVG WELL TO OUR NORTH...ACRS THE GREAT LAKES. AFTERWARD...WE REMAIN IN A BROAD TROF THRU THE END OF THE PERIOD WITH ANOTHER IMPLSE APPROACHING OUR FA SAT NIGHT. ASSOCIATED CDFNT WILL MOVE THRU FRI...WITH A RIDGE OF HI PRES IN ITS WAKE FOR FRI NIGHT AND MUCH OF SAT. WILL CONTINUE CHC POPS FOR LIGHT SNOW PRECEDING FRONT...MAINLY IN THE FIRST HALF OF THE DAY. A REINFORCING SHOT OF COLD AIR...ASSOCIATED WITH AFOREMENTIONED IMPULSE...WILL LIKELY MOVE THRU OUR FA SAT NIGHT. WILL DOWNPLAY THE NAM/WRF DEEPER MOISTURE PRECEDING AND WITH FRONT AND CONT A PARTLY CLOUDY FCST...CLOSER TO THE GFS. 11 SUN THRU WED... VERY COLD AND MAINLY DRY THRU THIS PERIOD. BROAD UPR LEVEL TROF WILL RESIDE ACRS THE OH VLY THRU LATE MON WITH AXIS SHIFTING INTO NEW ENGLAND TUE AND OFF THE NEW ENGLAND COAST WED. AFTER AXIS PASSAGE MON...OUR REGION WILL BE IN COLD NW FLO THRU THE END OF THE PERIOD. 00Z MEDIUM RANGE MODELS AND 12Z GFS ARE SIMILAR WITH SHOWING A FAST MOVG CLIPPER SYS/WEAK SFC LO MOVING INTO THE LOWER OH VLY SUN NGT AND EXITING MON MORNING. THIS APPEARS TO BE OUR BEST CHC FOR A MEASURABLE SNOW DURING THIS PERIOD WITH POSSIBLY A 1 TO 3 INCH DRY FLUFFY SNOW ACRS OUR FORECAST AREA(FA)...MOSTLY OVER OUR NRN/ERN FA. TEMPS WILL BE UNSEASONALLY COLD...ESPECIALLY AFTER CLIPPER PASSAGE MON WITH SINGLE DIGIT READINGS MON AND TUE NGT AS ARCTIC HI PRES BUILDS INTO AND OVER THE LOWER OH VLY. AFTER POPULATING WITH HPC GRIDS FOR TUE AND WED...WILL MAKE THE FOLLOWING CHGS TO TEMP GRIDS. WILL RAISE SUN NGT MINS CONSIDERABLY TO ACCOUNT FOR INCREASING CLOUDS/A BRIEF PERIOD OF WARM ADVECTION AHEAD OF CLIPPER. WILL RAISE MAXS MON A FEW DEGREES CLOSER TO ENSEMBLE MEANS AND HPC AND TO AGREE BETTER WITH OUR NEIGHBORS. IF WE GET AN INCH OR TWO OF SNOW COVER BEFORE THIS PERIOD AND ON SUN NGT AS WELL...THESE TEMPS WILL NEED TO BE ADJUSTED DOWN...IN OTHER WORDS...BELOW ZERO FOR MINS BEGINNING MON NGT. DK && .AVIATION (18Z TAFS)... VFR CONDITIONS WILL CONTINUE FOR THE SDF...LEX AND BWG TAF SITES THROUGH THE FIRST SIX HOURS OF THIS TAF FORECAST. HIGH PRESSURE OVERHEAD WILL KEEP MOSTLY SUNNY CONDITIONS WITH LIGHT VARIABLE TO SOUTH WINDS...5 TO 10 MPH. MID-LEVEL DECK WILL FILTER IN FROM THE WEST FROM 21-00Z THIS EVENING. CIGS SHOULD STAY VFR UNTIL 06Z FOR BWG...AND BY 10Z AND 12Z FOR SDF AND LEX RESPECTIVELY...WHERE LIGHT SNOW MAY REDUCE VISBYS DOWN TO ONE MILE OR SO AT TIMES. ONSET OF -SN WILL BE LIGHT DUE TO LOWER LEVELS NOT BEING FULLY SATURATED. MAY CARRY A TEMPO FOR HEAVIER SNOW FOR THE BWG TAF ROUGHLY FROM 10-14Z. ONCE SNOW BEGINS...MAY TREND TOWARD LOWER END MVFR CIGS AND IFR VISBYS WITH THE HEAVIER SNOW SOMETIME BETWEEN 12-18Z FOR ALL TAF SITES. AL && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 5 AM EST /4 AM CST/ TO 1 PM EST /12 PM CST/ THURSDAY FOR KYZ062>066-070>078-081-082. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 324 PM EST WED JAN 31 2007 .SHORT TERM... (TONIGHT THROUGH THURSDAY NIGHT)... ...SNOW ADVISORY ACROSS SOUTHERN KY AND SOUTHERN BLUEGRASS... SHORT-TERM FORECAST REVOLVES AROUND SOUTHERN STREAM SYSTEMS AND SNOW ACCUMULATION CHANCES WITH EACH. TONIGHT-MIDDAY THURS... HIGH PRESSURE OVERHEAD WILL MOVE OFF TO THE EAST TONIGHT...AS AN INVERTED TROUGH OVER THE GULF MOVES FROM TEXAS TOWARD THE CAROLINAS. MOISTURE IS NOT TOO IMPRESSIVE WITH THIS SYSTEM...HOWEVER THE DYNAMICS ARE STRONG. SOUTHERN JET OF ROUGHLY 150 KTS OR SO WILL BE OVERHEAD...WITH THE CWA UNDER THE LEFT-EXIT REGION AFTER MIDNIGHT. AMPLE LIFT WILL THUS HELP SNOW DEVELOP AFTER MIDNIGHT TOWARD MORNING. AREA SOUNDINGS INDICATE THE BEST CHANCE OF SNOW WILL BE BETWEEN 10-17Z. SOME HEAVIER SNOW MAY MIX IN AT TIMES GIVEN UPSTREAM REPORTS AND PROGGED -EPV ALOFT CO-LOCATED WITH MAX OMEGAS. BUT GIVEN THE LACK OF MOISTURE AND SPEED OF SYSTEM...WILL NOT GET CARRIED AWAY WITH SNOW AMOUNTS. THUS...WILL ISSUE A SNOW ADVSY FROM 1-2 INCHES POSSIBLE MAINLY SE OF A LINE FROM MORGANTOWN TO LEBANON. MAY BE A BIT TOO FAR NORTH WITH THE ADVY GIVEN THE NAM 18Z RUN...BUT 12Z GFS/NAM AND HPC INDICATE FAR SRN KY COULD GET THESE ACCUMULATING SNOWS. THE BIGGER PROBLEM WILL BE TIMING NOT THE ACTUAL ACCUMS. GIVEN TIME OF DAY (NEAR MORNING COMMUTE TIME) FELT IT WAS WORTH BUMPING UP THE SPS TO AN ADVSY. WILL KEEP THE HIGHER SNOW AMOUNTS ACROSS THE FAR SERN CWA. ELSEWHERE...WILL CONTINUE SPS FOR AROUND AN INCH OF ACCUMULATION. FEEL THAT THE THREAT IS MINIMIZED ACROSS CENTRAL KY...HOWEVER A BETTER CHANCE MAY EXIST NEAR THE OHIO RIVER WITH THE DEFORMATION ZONE DEVELOPING FROM KC TO WICHITA. THIS SHOULD ALIGN SOMEWHERE ACROSS OUR NRN CWA...POSSIBLY NEAR THE KY/IN BORDER. SNOWFALL AMOUNTS WITHIN THE SPS AREA WILL BE HIGHER IN THE DEFORMATION ZONE...BUT IT IS STILL EXPECTED TO BE LIGHT SNOW ONLY. MAIN PRECIP WILL END BY MIDDAY (ADVY ENDS AT 18Z)...THOUGH LOW CLOUDS MAY CONTINUE THROUGH THE AFTERNOON. WITH THIS...EVEN A FEW LIGHT SHOWERS/FLURRIES MAY CONTINUE INTO THE AFTERNOON HOURS. SFC TEMPS MAY INCREASE ENOUGH ACROSS THE SOUTH WHERE A CHANGEOVER TO LIGHT RAIN/DRIZZLE MAY OCCUR. HAVE A RAIN/SNOW MIX ACROSS THE SOUTH FOR NOW. MIDDAY THURS-OVERNIGHT THURS... SECOND WAVE IN SOUTHERN STREAM WILL QUICKLY MOVE TOWARD THE EAST COAST RIGHT ON THE HEELS OF THE FIRST SYSTEM. THIS SYSTEM IS MORE OF A CLOSED SFC LOW AS OPPOSED TO A SFC TROUGH...AND IS COMBINED WITH EVEN STRONGER DYNAMICS ALOFT. HOWEVER MOISTURE IS EVEN MORE LACKING...BUT THE DYNAMICS ARE THERE FOR YET ANOTHER POSSIBLE ADVSY SITUATION THRS NIGHT-FRI MORN. WILL LOOK MORE AT IT TONIGHT AND TOMORROW MORNING...BUT WILL HIT IT HARD IN THE HWO. THIS LATTER SYSTEM WOULD BE MORE OF A CWA-WIDE EVENT TOO. WILL CONTINUE WITH ONE-INCH ACCUMS FOR NOW. AS FAR AS TEMPS GO THROUGH THE PERIOD...WILL ONLY DROP ABOUT 5 DEGREES TONIGHT BEFORE CLOUDS INCREASE OVERNIGHT AND KEEP OUR TEMPS STEADY. TOMORROW...WILL LIKELY HEAT UP...ESPECIALLY IN THE AFTERNOON. HOWEVER WILL UNDERCUT RUC13/GFS AS I FEEL THESE ARE RUNNING A BIT TOO HIGH. LOW TO MID 30S LOOK LIKELY FOR HIGHS THURS. AL .LONG TERM (FRI THRU WED)... FRI THRU SAT NGT... SHRTWV TROF WILL BE DROPPING DOWN INTO THE UPR MS VLY/WRN GREAT LAKES AT THE START OF THE PERIOD WITH MORE ENERGY ROUNDING THE BASE OF THE UPR LEVEL BROAD TROF TOWARD THE LOWER MS VLY. THIS ELONGATED AXIS OF HIER VORTICITY BECOMES INCREASINGLY SHEARED AS IT MOVES THRU OUR FA FRI WITH AFOREMENTIONED SHRTWV MOVG WELL TO OUR NORTH...ACRS THE GREAT LAKES. AFTERWARD...WE REMAIN IN A BROAD TROF THRU THE END OF THE PERIOD WITH ANOTHER IMPLSE APPROACHING OUR FA SAT NIGHT. ASSOCIATED CDFNT WILL MOVE THRU FRI...WITH A RIDGE OF HI PRES IN ITS WAKE FOR FRI NIGHT AND MUCH OF SAT. WILL CONTINUE CHC POPS FOR LIGHT SNOW PRECEDING FRONT...MAINLY IN THE FIRST HALF OF THE DAY. A REINFORCING SHOT OF COLD AIR...ASSOCIATED WITH AFOREMENTIONED IMPULSE...WILL LIKELY MOVE THRU OUR FA SAT NIGHT. WILL DOWNPLAY THE NAM/WRF DEEPER MOISTURE PRECEDING AND WITH FRONT AND CONT A PARTLY CLOUDY FCST...CLOSER TO THE GFS. 11 SUN THRU WED... VERY COLD AND MAINLY DRY THRU THIS PERIOD. BROAD UPR LEVEL TROF WILL RESIDE ACRS THE OH VLY THRU LATE MON WITH AXIS SHIFTING INTO NEW ENGLAND TUE AND OFF THE NEW ENGLAND COAST WED. AFTER AXIS PASSAGE MON...OUR REGION WILL BE IN COLD NW FLO THRU THE END OF THE PERIOD. 00Z MEDIUM RANGE MODELS AND 12Z GFS ARE SIMILAR WITH SHOWING A FAST MOVG CLIPPER SYS/WEAK SFC LO MOVING INTO THE LOWER OH VLY SUN NGT AND EXITING MON MORNING. THIS APPEARS TO BE OUR BEST CHC FOR A MEASURABLE SNOW DURING THIS PERIOD WITH POSSIBLY A 1 TO 3 INCH DRY FLUFFY SNOW ACRS OUR FORECAST AREA(FA)...MOSTLY OVER OUR NRN/ERN FA. TEMPS WILL BE UNSEASONALLY COLD...ESPECIALLY AFTER CLIPPER PASSAGE MON WITH SINGLE DIGIT READINGS MON AND TUE NGT AS ARCTIC HI PRES BUILDS INTO AND OVER THE LOWER OH VLY. AFTER POPULATING WITH HPC GRIDS FOR TUE AND WED...WILL MAKE THE FOLLOWING CHGS TO TEMP GRIDS. WILL RAISE SUN NGT MINS CONSIDERABLY TO ACCOUNT FOR INCREASING CLOUDS/A BRIEF PERIOD OF WARM ADVECTION AHEAD OF CLIPPER. WILL RAISE MAXS MON A FEW DEGREES CLOSER TO ENSEMBLE MEANS AND HPC AND TO AGREE BETTER WITH OUR NEIGHBORS. IF WE GET AN INCH OR TWO OF SNOW COVER BEFORE THIS PERIOD AND ON SUN NGT AS WELL...THESE TEMPS WILL NEED TO BE ADJUSTED DOWN...IN OTHER WORDS...BELOW ZERO FOR MINS BEGINNING MON NGT. DK && .AVIATION (18Z TAFS)... VFR CONDITIONS WILL CONTINUE FOR THE SDF...LEX AND BWG TAF SITES THROUGH THE FIRST SIX HOURS OF THIS TAF FORECAST. HIGH PRESSURE OVERHEAD WILL KEEP MOSTLY SUNNY CONDITIONS WITH LIGHT VARIABLE TO SOUTH WINDS...5 TO 10 MPH. MID-LEVEL DECK WILL FILTER IN FROM THE WEST FROM 21-00Z THIS EVENING. CIGS SHOULD STAY VFR UNTIL 06Z FOR BWG...AND BY 10Z AND 12Z FOR SDF AND LEX RESPECTIVELY...WHERE LIGHT SNOW MAY REDUCE VISBYS DOWN TO ONE MILE OR SO AT TIMES. ONSET OF -SN WILL BE LIGHT DUE TO LOWER LEVELS NOT BEING FULLY SATURATED. MAY CARRY A TEMPO FOR HEAVIER SNOW FOR THE BWG TAF ROUGHLY FROM 10-14Z. ONCE SNOW BEGINS...MAY TREND TOWARD LOWER END MVFR CIGS AND IFR VISBYS WITH THE HEAVIER SNOW SOMETIME BETWEEN 12-18Z FOR ALL TAF SITES. AL && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 5 AM EST /4 AM CST/ TO 1 PM EST /12 PM CST/ THURSDAY FOR KYZ062>066-070>078-081-082. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1107 AM EST WED JAN 31 2007 .MORNING UPDATE... DOING A QUICK UPDATE TO REMOVE MORNING WORDING. LOWERED HIGH TEMPS A FEW DEGREES TODAY AS HOURLIES WERE RUNNING A BIT COOLER THAN WHAT THE GRIDS REFLECTED. SHOULD BE MOSTLY SUNNY AND TEMPS WILL WARM UP TO THE MID AND UPPER 20S...WITH NEAR FREEZING TEMPS ACROSS SRN KY UNDER HIGH PRESSURE. SINCE THE WINDS ARE LIGHT...WIND CHILLS NOT A FACTOR TODAY DESPITE IT BEING COLD. CLOUDS WILL BE ON THE INCREASE LATER THIS AFTERNOON...WITH MID TO UPPER LEVEL CLOUDS FILTERING IN DOWNSTREAM OF GULF COAST SYSTEM. UPDATE OUT SHORTLY. AL && .PREV DISCUSSION... SHORT TERM (TODAY-FRIDAY)... TODAY... SCT STRATOCU CURRENTLY FROM NEAR CVG TO SDF TO OWB FCST TO SLIDE ESE THROUGH THE EARLY MORNING HOURS. A COUPLE FLURRIES NOT OUT OF THE QUESTION ASSOC WITH THESE CLOUDS. MOST OF THE CWA WILL START OFF PARTLY CLOUDY BEFORE DAWN...BUT QUICKLY GO SUNNY THIS MORNING. TEMPS WILL BE QUITE COLD...MOST LOCATIONS IN THE LOWER TEENS TO UPPER SINGLE DIGITS. HOWEVER HIGH PRES MOVING INTO THE AREA WILL RESULT IN LIGHT WESTERLY WINDS...SO WIND CHILLS WILL NOT BE A SIGNIFICANT PROBLEM. THERE IS AN APPRECIABLE SPREAD IN THE MOS GUIDANCE FOR HIGH TEMPS TODAY...BIGGEST AT LEX WHERE NAM-MOS SHOWS 27 WHILE GFS-MOS PREDICTS A HIGH OF 35! NGM NUMBERS ARE CLOSER TO COOLER NAM-MOS. A BLEND OF RAW GFS/NAM DATA YIELD HIGHS RANGING FROM THE UPPER 20S FAR NORTHEAST TO THE MIDDLE 30S IN THE SOUTHWEST...AND THIS SEEMS REASONABLE. CS TONIGHT-FRIDAY... THE TIMING AND AMOUNTS OF WINTERY PRECIP ARE THE MAIN CONCERNS FOR LATE TONIGHT THROUGH FRIDAY MORNING. UPPER AIR PATTERN WILL HAVE A BROAD POSITIVELY TILTED TROUGH CENTERED ACROSS THE ROCKIES...WITH ZONAL FLOW DOWNSTREAM ACROSS THE SOUTHERN STATES. WITH THIS PATTERN...ANY UPPER AIR DISTURBANCES WILL BE QUITE SHEARED IN A CONFLUENT UPPER PATTERN ACROSS THE LOWER OHIO VALLEY. ONE THING TO NOTE IS A SHARPENING JET STREAK THAT WILL DEVELOP AND MOVE ACROSS THE TENNESSEE VALLEY EARLY THURSDAY. LIFT ASSOCIATED WITH THE LEFT FRONT QUADRANT OF THIS JET WILL MOVE ACROSS THE LOWER OHIO VALLEY AND PROVIDE A CHANCE OF SNOW BEGINNING EARLY THURSDAY. AT THE SURFACE...ARCTIC HIGH PRESSURE WILL MOVE OFF THE MID ATLANTIC SEABOARD EARLY THURSDAY. THIS WILL ALLOW SOUTHWESTERLY MID LEVEL FLOW TO RESUME ABOVE COLDER AIR IN PLACE WITHIN THE BOUNDARY LAYER. MAIN AXIS OF MOISTURE WILL REMAIN SOUTH...WHERE PLENTY OF RAIN IS EXPECTED ACROSS THE NORTHERN GULF STATES ASSOCIATED WITH AN ELEVATED WARM FRONT. FARTHER NORTH...LIFT WILL OCCUR WITH MUCH LESS MOISTURE AVAILABLE AND WILL BE A RESULT OF UPPER AIR DYNAMICS. BOTH ETA AND GFS HINT AT POSSIBLY TWO SEPARATE EPISODES OF WINTERY PRECIPITATION. THE FIRST WILL MOVE ACROSS OUR CWA EARLY THURSDAY...AND THE SECOND...LATE THURSDAY AND EARLY FRIDAY. FORECAST SOUNDINGS SHOW BASICALLY ALL OF CENTRAL KENTUCKY COLD ENOUGH FOR ALL SNOW WITH THIS FIRST EPISODE. MOISTURE WILL BE SCANT...BUT WITH RAIN/SNOW RATIOS GREATER THAN 10 TO 1 SOME LIGHT ACCUMULATIONS... PERHAPS AN INCH OR TWO...LOOK LIKELY. INITIALLY...VERY DRY LOW LEVEL AIR WILL BE IN PLACE EARLY THURSDAY...THIS I THINK WILL HELP KEEP PRECIP ALL SNOW AT THE BEGINNING...BUT ALSO MAY DELAY THE ONSET...WHICH SHOULD BE DURING THE PRE-DAWN HOURS. BY LATE THURSDAY...A WEAK UPPER AIR DISTURBANCE IS FORECAST BY BOTH THE NAM AND THE GFS TO MOVE ACROSS OUR REGION. A SECOND ROUND OF LIGHT PRECIP WILL BE ASSOCIATED WITH THIS...BUT WARMER BOUNDARY LAYER TEMPERATURES ACROSS THE SOUTHERN THIRD OF KENTUCKY MAY ALLOW SOME RAIN TO MIX IN WITH THE SNOW. ANY SNOW AMOUNTS WITH THIS WILL BE LIGHT AS WELL...WITH SNOW ACCUMULATIONS POSSIBLY APPROACHING ONE INCH. WIND WILL SHIFT TO THE WEST FRIDAY AFTERNOON AS A SURFACE TROUGH MOVES ACROSS THE GREAT LAKES. COLDER AIR WILL ARRIVE FRIDAY AFTERNOON AS FLURRIES WILL BE ENDING. TEMPERATURES WILL MODERATE THURSDAY AFTERNOON INTO FRIDAY MORNING...WITH HIGHS AS WARM AS THE MID 30S THURSDAY AFTERNOON ACROSS THE SOUTH. JSD LONG TERM (SATURDAY-TUESDAY)... DEEP POLAR VORTEX JUST SOUTHWEST OF HUDSON`S BAY WILL KEEP VERY COLD AIR LOCKED IN PLACE ACROSS THE UPPER MIDWEST AND THE GREAT LAKES. COLD AIR WILL BE IN PLACE ACROSS THE REGION SATURDAY AS HIGH PRESSURE MOVES INTO THE SOUTHERN PLAINS. FRIGID AIR WILL ARRIVE LATE SATURDAY AND CONTINUE THROUGH TUESDAY TWO ARCTIC FRONTS ARE FORECAST TO MOVE THROUGH KENTUCKY...ONE LATE SATURDAY AND THE SECOND ONE EARLY MONDAY. IT`S POSSIBLE THAT MONDAY AND TUESDAY WILL HAVE THE COLDEST TEMPERATURES SINCE LATE DECEMBER 2004. JSD AVIATION (12Z TAFS)... BAND OF STRATOCU HAS BEEN PERSISTENT...CURRENTLY POSITIONED FROM NEAR SDF TO LEX. BASED ON SATELLITE TRENDS AND LATEST RUC RH FIELDS...EXPECT CLOUDS TO PROGRESS OFF TO THE ESE AFFECTING THE SDF TAF SITE THROUGH 12-13Z...LEX THROUGH 14Z. CIGS ARE NOT TOO LOW... AROUND 2.5KFT. A FEW FLURRIES POSSIBLE WITHIN THIS BAND OF CLOUDS BUT VSBYS WILL BE UNRESTRICTED. VFR/SKC FROM MID MORNING INTO THE AFTN HOURS AT ALL TAF SITES. MID/HIGH LEVEL CLOUDS FCST TO MOVE INTO THE REGION TOWARD 21Z...WITH CIGS DROPPING BELOW 10KFT AFTER 0Z. BASED ON LATEST NAM BUFKIT DATA...WILL INTRODUCE -SN AFTER 6Z FROM SW TO NE...BUT WILL KEEP CIGS AOA 2KFT THROUGH 12Z/THU. CS && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 605 AM EST WED JAN 31 2007 .AVIATION (12Z TAFS)... BAND OF STRATOCU HAS BEEN PERSISTENT...CURRENTLY POSITIONED FROM NEAR SDF TO LEX. BASED ON SATELLITE TRENDS AND LATEST RUC RH FIELDS...EXPECT CLOUDS TO PROGRESS OFF TO THE ESE AFFECTING THE SDF TAF SITE THROUGH 12-13Z...LEX THROUGH 14Z. CIGS ARE NOT TOO LOW... AROUND 2.5KFT. A FEW FLURRIES POSSIBLE WITHIN THIS BAND OF CLOUDS BUT VSBYS WILL BE UNRESTRICTED. VFR/SKC FROM MID MORNING INTO THE AFTN HOURS AT ALL TAF SITES. MID/HIGH LEVEL CLOUDS FCST TO MOVE INTO THE REGION TOWARD 21Z...WITH CIGS DROPPING BELOW 10KFT AFTER 0Z. BASED ON LATEST NAM BUFKIT DATA...WILL INTRODUCE -SN AFTER 6Z FROM SW TO NE...BUT WILL KEEP CIGS AOA 2KFT THROUGH 12Z/THU. CS .SHORT TERM (TODAY-FRIDAY)... TODAY... SCT STRATOCU CURRENTLY FROM NEAR CVG TO SDF TO OWB FCST TO SLIDE ESE THROUGH THE EARLY MORNING HOURS. A COUPLE FLURRIES NOT OUT OF THE QUESTION ASSOC WITH THESE CLOUDS. MOST OF THE CWA WILL START OFF PARTLY CLOUDY BEFORE DAWN...BUT QUICKLY GO SUNNY THIS MORNING. TEMPS WILL BE QUITE COLD...MOST LOCATIONS IN THE LOWER TEENS TO UPPER SINGLE DIGITS. HOWEVER HIGH PRES MOVING INTO THE AREA WILL RESULT IN LIGHT WESTERLY WINDS...SO WIND CHILLS WILL NOT BE A SIGNIFICANT PROBLEM. THERE IS AN APPRECIABLE SPREAD IN THE MOS GUIDANCE FOR HIGH TEMPS TODAY...BIGGEST AT LEX WHERE NAM-MOS SHOWS 27 WHILE GFS-MOS PREDICTS A HIGH OF 35! NGM NUMBERS ARE CLOSER TO COOLER NAM-MOS. A BLEND OF RAW GFS/NAM DATA YIELD HIGHS RANGING FROM THE UPPER 20S FAR NORTHEAST TO THE MIDDLE 30S IN THE SOUTHWEST...AND THIS SEEMS REASONABLE. CS TONIGHT-FRIDAY... THE TIMING AND AMOUNTS OF WINTERY PRECIP ARE THE MAIN CONCERNS FOR LATE TONIGHT THROUGH FRIDAY MORNING. UPPER AIR PATTERN WILL HAVE A BROAD POSITIVELY TILTED TROUGH CENTERED ACROSS THE ROCKIES...WITH ZONAL FLOW DOWNSTREAM ACROSS THE SOUTHERN STATES. WITH THIS PATTERN...ANY UPPER AIR DISTURBANCES WILL BE QUITE SHEARED IN A CONFLUENT UPPER PATTERN ACROSS THE LOWER OHIO VALLEY. ONE THING TO NOTE IS A SHARPENING JET STREAK THAT WILL DEVELOP AND MOVE ACROSS THE TENNESSEE VALLEY EARLY THURSDAY. LIFT ASSOCIATED WITH THE LEFT FRONT QUADRANT OF THIS JET WILL MOVE ACROSS THE LOWER OHIO VALLEY AND PROVIDE A CHANCE OF SNOW BEGINNING EARLY THURSDAY. AT THE SURFACE...ARCTIC HIGH PRESSURE WILL MOVE OFF THE MID ATLANTIC SEABOARD EARLY THURSDAY. THIS WILL ALLOW SOUTHWESTERLY MID LEVEL FLOW TO RESUME ABOVE COLDER AIR IN PLACE WITHIN THE BOUNDARY LAYER. MAIN AXIS OF MOISTURE WILL REMAIN SOUTH...WHERE PLENTY OF RAIN IS EXPECTED ACROSS THE NORTHERN GULF STATES ASSOCIATED WITH AN ELEVATED WARM FRONT. FARTHER NORTH...LIFT WILL OCCUR WITH MUCH LESS MOISTURE AVAILABLE AND WILL BE A RESULT OF UPPER AIR DYNAMICS. BOTH ETA AND GFS HINT AT POSSIBLY TWO SEPARATE EPISODES OF WINTERY PRECIPITATION. THE FIRST WILL MOVE ACROSS OUR CWA EARLY THURSDAY...AND THE SECOND...LATE THURSDAY AND EARLY FRIDAY. FORECAST SOUNDINGS SHOW BASICALLY ALL OF CENTRAL KENTUCKY COLD ENOUGH FOR ALL SNOW WITH THIS FIRST EPISODE. MOISTURE WILL BE SCANT...BUT WITH RAIN/SNOW RATIOS GREATER THAN 10 TO 1 SOME LIGHT ACCUMULATIONS... PERHAPS AN INCH OR TWO...LOOK LIKELY. INITIALLY...VERY DRY LOW LEVEL AIR WILL BE IN PLACE EARLY THURSDAY...THIS I THINK WILL HELP KEEP PRECIP ALL SNOW AT THE BEGINNING...BUT ALSO MAY DELAY THE ONSET...WHICH SHOULD BE DURING THE PRE-DAWN HOURS. BY LATE THURSDAY...A WEAK UPPER AIR DISTURBANCE IS FORECAST BY BOTH THE NAM AND THE GFS TO MOVE ACROSS OUR REGION. A SECOND ROUND OF LIGHT PRECIP WILL BE ASSOCIATED WITH THIS...BUT WARMER BOUNDARY LAYER TEMPERATURES ACROSS THE SOUTHERN THIRD OF KENTUCKY MAY ALLOW SOME RAIN TO MIX IN WITH THE SNOW. ANY SNOW AMOUNTS WITH THIS WILL BE LIGHT AS WELL...WITH SNOW ACCUMULATIONS POSSIBLY APPROACHING ONE INCH. WIND WILL SHIFT TO THE WEST FRIDAY AFTERNOON AS A SURFACE TROUGH MOVES ACROSS THE GREAT LAKES. COLDER AIR WILL ARRIVE FRIDAY AFTERNOON AS FLURRIES WILL BE ENDING. TEMPERATURES WILL MODERATE THURSDAY AFTERNOON INTO FRIDAY MORNING...WITH HIGHS AS WARM AS THE MID 30S THURSDAY AFTERNOON ACROSS THE SOUTH. JSD .LONG TERM (SATURDAY-TUESDAY)... DEEP POLAR VORTEX JUST SOUTHWEST OF HUDSON`S BAY WILL KEEP VERY COLD AIR LOCKED IN PLACE ACROSS THE UPPER MIDWEST AND THE GREAT LAKES. COLD AIR WILL BE IN PLACE ACROSS THE REGION SATURDAY AS HIGH PRESSURE MOVES INTO THE SOUTHERN PLAINS. FRIGID AIR WILL ARRIVE LATE SATURDAY AND CONTINUE THROUGH TUESDAY TWO ARCTIC FRONTS ARE FORECAST TO MOVE THROUGH KENTUCKY...ONE LATE SATURDAY AND THE SECOND ONE EARLY MONDAY. IT`S POSSIBLE THAT MONDAY AND TUESDAY WILL HAVE THE COLDEST TEMPERATURES SINCE LATE DECEMBER 2004. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1220 PM EST TUE JAN 30 2007 .AVIATION (18Z TAFS)... GUSTY NORTHWEST WINDS TO 22KTS ARE EXPECTED IN THE WAKE OF A COLD FRONT WHICH HAS MOVED EAST OF THE TAF SITES. THESE GUSTY WINDS WILL DIMINISH AROUND 00Z. SCT TO BKN CU WILL BE POSSIBLE ACROSS SDF AND LEX THIS AFTERNOON AS AN UPPER TROUGH MOVES THROUGH THE LOWER OHIO VALLEY. CLEAR SKIES AND VFR VSBYS EXPECTED AFTER 02Z. --JA .SHORT TERM (THIS AFTERNOON)... AT 16Z A COLD FRONT WAS LOCATED EAST OF A LINE FROM WINCHESTER IN CENTRAL KY TO GLASGOW. TEMPERATURES HAD DROPPED 5 TO 10 DEGREES JUST AFTER THE FRONTAL PASSAGE AND LOOKING UP STREAM READINGS WERE IN THE TEENS. JUST LIKE SUNDAY... DEW POINTS HAVE DROPPED INTO THE SINGLE DIGITS ACROSS THE NORTHERN PORTION OF THE CWFA. WILL CONTINUE TO MENTION ISOLATED TO LIGHT SNOW SHOWERS THIS AFTERNOON AS CU FIELD DEVELOPS BEHIND THE FRONT AND WITH STEEPENING LAPSE RATES. TEMPERATURES WILL CONTINUE THEIR SLOW DOWNWARD TREND EVEN WITH SOME SUNSHINE. UPDATED FORECAST OUT BY 1115. --JA PREVIOUS DISCUSSION BELOW. CLIPPER SHORT WAVE MOVING ESE THROUGH IOWA INTO IL/IN ATTM...WITH ASSOC SFC TROF/FRONT STRETCHING FROM NEAR IND TO PAH AS OF 6Z. MOISTURE POOLING ALONG THE FRONT...WITH DEWPOINTS RISING INTO THE MID 20S. SCT SHSN HAVE DEVELOPED ALONG/AHEAD OF THE SFC FRONT...WITH A FEW MOVING INTO THE LMK CWA AND AS FAR S AS NEAR LEITCHFIELD. RECENT ACARS DATA AT KSDF SHOW VERY STEEP LAPSE RATES TO 700MB... HELPING PROMOTE THIS PRECIP. EXPECT ISLTD-SCT SHSN TO REMAIN POSSIBLE THROUGH THE MORNING HOURS...WITH HIGHEST CHCS OVER THE N 1/2 OF THE CWA...DECREASING SOUTHWARD. ANY SNOW AMTS SHOULD BE MINOR AT BEST THOUGH SOME OF THE SHSN HAVE BEEN INTENSE OVER IL/IN/OH BASED ON RADAR REFLECTIVITIES NEAR 35DBZ OR HIGHER...SO IF SOME OF THESE WERE TO AFFECT OUR CWA THERE COULD BE LOCALIZED ACCUMS OF A COUPLE TENTHS OF AN INCH IN A SHORT PERIOD OF TIME. WILL CONTINUE TO MONITOR AS WE GET CLOSER TO THE MORNING DRIVE. BASED ON NAM/RUC...SFC FRONT WILL PASS THROUGH WRN COUNTIES AROUND 10-12Z...INTO ERN/SRN COUNTIES 12-14Z TIMEFRAME. THIS WILL BRING A ROUND OF GUSTY W/NW WINDS TODAY. BUFKIT DIAGNOSTICS INDICATE GUSTS TO 20-25KTS POSSIBLE AND THIS SEEMS REASONABLE BASED ON UPSTREAM OBSERVATIONS. THIS WILL ALSO BRING STEADY OR FALLING TEMPS (EXCEPT PERHAPS THE FAR SE COUNTIES). HAVE FOLLOWED A RUC/NAM BLEND FOR TEMPS TODAY INTO TONIGHT. CHANCES FOR SHSN WILL CONTINUE INTO THE AFTN WITH STEEP LAPSE RATES...THOUGH FEEL THAT OVERALL THREAT WILL BE LOWER THAN IN THE MORNING DUE TO SIGNIFICANTLY DRIER AIR ADVECTING INTO THE LOWER OHIO VALLEY. DEWPOINTS WILL LIKELY FALL INTO THE SINGLE DIGITS THIS AFTN. WILL WORD AFTERNOON POPS AS CHANCE VERSUS MORNING COVERAGE WORDING. GUSTY WINDS WILL LIGHTEN AFTER SUNSET...THOUGH BEFORE THAT OCCURS WIND CHILL VALUES THIS AFTN INTO THE EARLY EVENING WILL LIKELY DROP INTO THE SINGLE DIGITS WITH A FEW NEAR-ZERO VALUES POSSIBLE. HAVE ALLOWED SKIES TO CLEAR OVERNIGHT...THOUGH DID NOT GO WITH COMPLETE CLEARING SINCE NAM AND TO A LESSER EXTENT GFS SUGGEST AN AREA OF 3-5KFT CLOUDS SWEEPING ACROSS THE CWA BETWEEN 6-9Z/WED (OVERNIGHT). CS && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1105 AM EST TUE JAN 30 2007 .SHORT TERM (THIS AFTERNOON)... AT 16Z A COLD FRONT WAS LOCATED EAST OF A LINE FROM WINCHESTER IN CENTRAL KY TO GLASGOW. TEMPERATURES HAD DROPPED 5 TO 10 DEGREES JUST AFTER THE FRONTAL PASSAGE AND LOOKING UP STREAM READINGS WERE IN THE TEENS. JUST LIKE SUNDAY... DEW POINTS HAVE DROPPED INTO THE SINGLE DIGITS ACROSS THE NORTHERN PORTION OF THE CWFA. WILL CONTINUE TO MENTION ISOLATED TO LIGHT SNOW SHOWERS THIS AFTERNOON AS CU FIELD DEVELOPS BEHIND THE FRONT AND WITH STEEPENING LAPSE RATES. TEMPERATURES WILL CONTINUE THEIR SLOW DOWNWARD TREND EVEN WITH SOME SUNSHINE. UPDATED FORECAST OUT BY 1115. --JA PREVIOUS DISCUSSION BELOW. CLIPPER SHORT WAVE MOVING ESE THROUGH IOWA INTO IL/IN ATTM...WITH ASSOC SFC TROF/FRONT STRETCHING FROM NEAR IND TO PAH AS OF 6Z. MOISTURE POOLING ALONG THE FRONT...WITH DEWPOINTS RISING INTO THE MID 20S. SCT SHSN HAVE DEVELOPED ALONG/AHEAD OF THE SFC FRONT...WITH A FEW MOVING INTO THE LMK CWA AND AS FAR S AS NEAR LEITCHFIELD. RECENT ACARS DATA AT KSDF SHOW VERY STEEP LAPSE RATES TO 700MB... HELPING PROMOTE THIS PRECIP. EXPECT ISLTD-SCT SHSN TO REMAIN POSSIBLE THROUGH THE MORNING HOURS...WITH HIGHEST CHCS OVER THE N 1/2 OF THE CWA...DECREASING SOUTHWARD. ANY SNOW AMTS SHOULD BE MINOR AT BEST THOUGH SOME OF THE SHSN HAVE BEEN INTENSE OVER IL/IN/OH BASED ON RADAR REFLECTIVITIES NEAR 35DBZ OR HIGHER...SO IF SOME OF THESE WERE TO AFFECT OUR CWA THERE COULD BE LOCALIZED ACCUMS OF A COUPLE TENTHS OF AN INCH IN A SHORT PERIOD OF TIME. WILL CONTINUE TO MONITOR AS WE GET CLOSER TO THE MORNING DRIVE. BASED ON NAM/RUC...SFC FRONT WILL PASS THROUGH WRN COUNTIES AROUND 10-12Z...INTO ERN/SRN COUNTIES 12-14Z TIMEFRAME. THIS WILL BRING A ROUND OF GUSTY W/NW WINDS TODAY. BUFKIT DIAGNOSTICS INDICATE GUSTS TO 20-25KTS POSSIBLE AND THIS SEEMS REASONABLE BASED ON UPSTREAM OBSERVATIONS. THIS WILL ALSO BRING STEADY OR FALLING TEMPS (EXCEPT PERHAPS THE FAR SE COUNTIES). HAVE FOLLOWED A RUC/NAM BLEND FOR TEMPS TODAY INTO TONIGHT. CHANCES FOR SHSN WILL CONTINUE INTO THE AFTN WITH STEEP LAPSE RATES...THOUGH FEEL THAT OVERALL THREAT WILL BE LOWER THAN IN THE MORNING DUE TO SIGNIFICANTLY DRIER AIR ADVECTING INTO THE LOWER OHIO VALLEY. DEWPOINTS WILL LIKELY FALL INTO THE SINGLE DIGITS THIS AFTN. WILL WORD AFTERNOON POPS AS CHANCE VERSUS MORNING COVERAGE WORDING. GUSTY WINDS WILL LIGHTEN AFTER SUNSET...THOUGH BEFORE THAT OCCURS WIND CHILL VALUES THIS AFTN INTO THE EARLY EVENING WILL LIKELY DROP INTO THE SINGLE DIGITS WITH A FEW NEAR-ZERO VALUES POSSIBLE. HAVE ALLOWED SKIES TO CLEAR OVERNIGHT...THOUGH DID NOT GO WITH COMPLETE CLEARING SINCE NAM AND TO A LESSER EXTENT GFS SUGGEST AN AREA OF 3-5KFT CLOUDS SWEEPING ACROSS THE CWA BETWEEN 6-9Z/WED (OVERNIGHT). CS .AVIATION (12Z TAFS)... COLD FRONT NOW ROLLING THROUGH THE LMK CWA AS OF 11Z...WITH WINDS AT HNB SOLIDLY NW WHILE DIRECTIONS AT SDF/FTK SWITCHING SOON. WITH FROPA...WE EXPECT WNW WINDS WILL INCREASE AND BECOME GUSTY. GUSTS TO 20-25KTS ARE LIKELY THROUGH AT LEAST MID-AFTERNOON TODAY. SHSN ARE WIDELY SCATTERED AT THIS POINT AND CIGS ARE VFR-MVFR UPSTREAM OVER SRN IL AND SW IN. LATEST NAM SHOWS CIGS DROPPING TO AROUND 3000 FEET THIS MORNING AT SDF/LEX...THEN RISING TO NEAR 5KFT WITH SKIES ACTUALLY GOING SCT (EVEN FEW OVER SRN KY). -SHSN THREAT FOR THE TAF SITES SEEMS MINIMAL...WILL NOT MENTION IN PREVAILING GROUPS AND HANDLE ANY -SHSN WITH TEMPO GROUPS IF NECESSARY. GFS/NAM HAVE BEEN CONSISTENT IN BRINGING AN AREA OF LOWER CIGS (~2KFT) TONIGHT BETWEEN 0Z-6Z...AND WILL ACCOUNT FOR THIS. WINDS WILL SUBSIDE CONSIDERABLY AFTER 3Z AS SFC HIGH PRES SLIDES INTO THE REGION. CS && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 605 AM EST TUE JAN 30 2007 .AVIATION (12Z TAFS)... COLD FRONT NOW ROLLING THROUGH THE LMK CWA AS OF 11Z...WITH WINDS AT HNB SOLIDLY NW WHILE DIRECTIONS AT SDF/FTK SWITCHING SOON. WITH FROPA...WE EXPECT WNW WINDS WILL INCREASE AND BECOME GUSTY. GUSTS TO 20-25KTS ARE LIKELY THROUGH AT LEAST MID-AFTERNOON TODAY. SHSN ARE WIDELY SCATTERED AT THIS POINT AND CIGS ARE VFR-MVFR UPSTREAM OVER SRN IL AND SW IN. LATEST NAM SHOWS CIGS DROPPING TO AROUND 3000 FEET THIS MORNING AT SDF/LEX...THEN RISING TO NEAR 5KFT WITH SKIES ACTUALLY GOING SCT (EVEN FEW OVER SRN KY). -SHSN THREAT FOR THE TAF SITES SEEMS MINIMAL...WILL NOT MENTION IN PREVAILING GROUPS AND HANDLE ANY -SHSN WITH TEMPO GROUPS IF NECESSARY. GFS/NAM HAVE BEEN CONSISTENT IN BRINGING AN AREA OF LOWER CIGS (~2KFT) TONIGHT BETWEEN 0Z-6Z...AND WILL ACCOUNT FOR THIS. WINDS WILL SUBSIDE CONSIDERABLY AFTER 3Z AS SFC HIGH PRES SLIDES INTO THE REGION. CS && .SHORT TERM (TODAY-TONIGHT)... CLIPPER SHORT WAVE MOVING ESE THROUGH IOWA INTO IL/IN ATTM...WITH ASSOC SFC TROF/FRONT STRETCHING FROM NEAR IND TO PAH AS OF 6Z. MOISTURE POOLING ALONG THE FRONT...WITH DEWPOINTS RISING INTO THE MID 20S. SCT SHSN HAVE DEVELOPED ALONG/AHEAD OF THE SFC FRONT...WITH A FEW MOVING INTO THE LMK CWA AND AS FAR S AS NEAR LEITCHFIELD. RECENT ACARS DATA AT KSDF SHOW VERY STEEP LAPSE RATES TO 700MB... HELPING PROMOTE THIS PRECIP. EXPECT ISLTD-SCT SHSN TO REMAIN POSSIBLE THROUGH THE MORNING HOURS...WITH HIGHEST CHCS OVER THE N 1/2 OF THE CWA...DECREASING SOUTHWARD. ANY SNOW AMTS SHOULD BE MINOR AT BEST THOUGH SOME OF THE SHSN HAVE BEEN INTENSE OVER IL/IN/OH BASED ON RADAR REFLECTIVITIES NEAR 35DBZ OR HIGHER...SO IF SOME OF THESE WERE TO AFFECT OUR CWA THERE COULD BE LOCALIZED ACCUMS OF A COUPLE TENTHS OF AN INCH IN A SHORT PERIOD OF TIME. WILL CONTINUE TO MONITOR AS WE GET CLOSER TO THE MORNING DRIVE. BASED ON NAM/RUC...SFC FRONT WILL PASS THROUGH WRN COUNTIES AROUND 10-12Z...INTO ERN/SRN COUNTIES 12-14Z TIMEFRAME. THIS WILL BRING A ROUND OF GUSTY W/NW WINDS TODAY. BUFKIT DIAGNOSTICS INDICATE GUSTS TO 20-25KTS POSSIBLE AND THIS SEEMS REASONABLE BASED ON UPSTREAM OBSERVATIONS. THIS WILL ALSO BRING STEADY OR FALLING TEMPS (EXCEPT PERHAPS THE FAR SE COUNTIES). HAVE FOLLOWED A RUC/NAM BLEND FOR TEMPS TODAY INTO TONIGHT. CHANCES FOR SHSN WILL CONTINUE INTO THE AFTN WITH STEEP LAPSE RATES...THOUGH FEEL THAT OVERALL THREAT WILL BE LOWER THAN IN THE MORNING DUE TO SIGNIFICANTLY DRIER AIR ADVECTING INTO THE LOWER OHIO VALLEY. DEWPOINTS WILL LIKELY FALL INTO THE SINGLE DIGITS THIS AFTN. WILL WORD AFTERNOON POPS AS CHANCE VERSUS MORNING COVERAGE WORDING. GUSTY WINDS WILL LIGHTEN AFTER SUNSET...THOUGH BEFORE THAT OCCURS WIND CHILL VALUES THIS AFTN INTO THE EARLY EVENING WILL LIKELY DROP INTO THE SINGLE DIGITS WITH A FEW NEAR-ZERO VALUES POSSIBLE. HAVE ALLOWED SKIES TO CLEAR OVERNIGHT...THOUGH DID NOT GO WITH COMPLETE CLEARING SINCE NAM AND TO A LESSER EXTENT GFS SUGGEST AN AREA OF 3-5KFT CLOUDS SWEEPING ACROSS THE CWA BETWEEN 6-9Z/WED (OVERNIGHT). CS .LONG TERM (WEDNESDAY-MONDAY)... ...ACTIVE WEATHER PERIOD WITH POTENTIAL FOR ACCUMULATING SNOWS LATE WED THROUGH THURSDAY NIGHT... WEDNESDAY THROUGH FRIDAY NIGHT... FAIRLY ACTIVE AND CHALLENGING FORECAST PERIOD APPEARS TO BE IN STORE FOR THIS PART OF THE FORECAST PERIOD. LATE EVENING MODELS CONTINUE TO BE IN GENERAL AGREEMENT WITH SOUTHWESTERN U.S. UPPER LEVEL WAVE EJECTING EASTWARD DURING THE PERIOD. ALL THE MODELS INDUCE SFC CYCLOGENESIS ACROSS THE DEEP SOUTH AND BRING A SFC LOW EASTWARD ACROSS THE NORTHERN GULF STATES. THE PAST FEW RUNS OF THE MODELS HAVE BEEN TRENDING NORTHWARD WITH THE TRACK OF THE SFC LOW ACROSS THE SOUTHEAST U.S. WE STILL HAVE TWO CAMPS OF TRACKS TONIGHT...WITH THE CANADIAN GLOBAL AND NAM-WRF BEING THE FARTHEST NORTH WITH THE LOW COMING ACROSS THE FA...WHILE THE UKMET AND EURO ARE FURTHER SOUTH. THE 00Z OP GFS IS BETWEEN THESE TWO CAMPS AND OFFERS A PRETTY GOOD COMPROMISE. USING A CONSENSUS OF THE MODEL DATA...WEDNESDAY WILL GENERALLY BE A DRY DAY WITH MID-HIGH LEVEL CLOUDS INCREASING FROM WEST TO EAST. ISENTROPIC UPGLIDE WILL INCREASE WEDNESDAY EVENING AS SFC LOW BEGINS ITS TREK TOWARDS THE NORTHEAST. ANTECEDENT DRY AIRMASS WILL TAKE SOME TIME TO MOISTEN UP WEDNESDAY NIGHT SO PRECIPITATION MAY NOT START UNTIL LATE WEDNESDAY NIGHT. NONETHELESS...IT DOES APPEAR PRECIPITATION WILL BE LIKELY AND THUS HAVE INCREASED POPS TO LIKELY FOR THIS PERIOD. MODEL PROFILES FROM THE GFS SUGGEST ALL SNOW AS THE PRECIPITATION TYPE FOR WEDNESDAY NIGHT. MAIN BULK OF PRECIPITATION WILL FALL ON THURSDAY AS ISENTROPIC LIFT AND FRONTOGENETICAL FORCING WILL BE MAXIMIZED OVER KENTUCKY. BANDED PRECIPITATION WILL LIKELY LIFT NORTHWARD THROUGH THE DAY AND BE ORIENTED ALONG THE OHIO RIVER BY EVENING. HAVE GONE WITH LIKELY POPS HERE BUT PRECIPITATION TYPE WILL BE CHALLENGING. IN THE PAST SEVERAL EVENTS...WE HAVE SEEN STORMS SYSTEMS OUT IN THE LONG RANGE BEING FORECAST TO GO SOUTH...ONLY TO SEE A NORTHWARD TRACK VERIFY AS THE EVENT CAME CLOSER/UNFOLDED. IN ADDITION...THE NUMERICAL MODELS HAVE HAD A TOUGH TIME ESTIMATING THE AMOUNT OF WARM AIR ADVECTING IN ALOFT...WHICH HAS RESULTED IN MORE LIQUID PRECIPITATION OCCURRING. TONIGHT...WE ARE IN THE SAME DILEMMA. BASED ON ALL THE AVAILABLE DATA...AND NOT COMPLETELY THROWING OUT THE NAM-WRF...AM INCLINED TO LEAVE A MIX OF RAIN/SLEET/SNOW IN ACROSS THE SOUTHERN FA SOUTH OF A LINE FROM NEAR HARTFORD TO JUST SOUTH OF RICHMOND. NORTH OF THAT LINE...FEEL THAT DOMINANT PRECIPITATION TYPE WILL BE SNOW. AS SFC LOW HEADS EAST THU NIGHT...SHOULD SEE ALL AREAS GO TO SNOW. ACCUMULATIONS OF SNOW APPEAR LIKELY AT THIS TIME WITH TWO TO FOUR INCHES ACROSS THE NORTHERN HALF OF THE FA WITH ONE TO TWO ACROSS SOUTHERN KY. HOWEVER...IF THE NORTHWARD TREND IN THE SURFACE TRACK OCCURS...LESS SNOW WILL BE LIKELY IN THE SOUTH AND THE 2-4 INCH BAND WOULD BE DISPLACED FURTHER NORTH...PROBABLY NORTH OF THE OHIO RIVER. GIVEN THIS EVENT IS SOME 60-72 HORUS...WILL ISSUE A SPECIAL WX STMT THIS MORNING HIGHLIGHT IMPACTS OF THE EVENT. SNOW WILL LIKELY CONTINUE THURSDAY NIGHT AND DIMINISH SOME BY FRIDAY. SECONDARY CLIPPER TYPE SYSTEM IS FORECAST TO SWING THROUGH THE REGION FRIDAY AFTERNOON AND EVENING AND MAY BRING ANOTHER ROUND OF SNOW SHOWERS TO THE REGION. THUS...HAVE PRETTY MUCH LEFT ONGOING FORECAST INTACT FOR FRIDAY AND FRIDAY NIGHT. AS FOR TEMPERATURES THROUGH THE PERIOD...GENERALLY FOLLOWED A BLEND OF OP GFS RAW SFC TEMPS WITH A SPLASH OF THE MOS STAT GUIDANCE. JARVIS FORECAST FROM SATURDAY ONWARD WAS LEFT AS IS...PREVIOUS FORECAST DISCUSSION FOLLOWS... WILL STAY CLOSE TO THE EURO THROUGH THE PERIOD...WITH SOME SUPPORT FROM THE GFS THROUGH THIS PERIOD AS WELL. INDICES (PNA/EPO/AO) STILL SUPPORT THE COLDER AIR TO CONTINUE TO REPLENISH ITSELF THROUGH THE NEXT FEW WEEKS. DEEP LONGWAVE TROUGH EXTENDS FROM HUDSON BAY POLAR VORTEX(PV) ROTATING FROM THE MS VALLEY THROUGH THE OHIO VALLEY OVER THE WEEKEND...WITH POSSIBLY THE COLDEST AIR OF THE WINTER TO DATE IN THIS PERIOD. SFC HI PRESSURE MOVES ACROSS THE REGION SATURDAY INTO SUNDAY...WEAK CLIPPER STILL LOOKS POSSIBLE SUNDAY EVENING INTO EARLY MONDAY BEFORE ANOTHER VERY COLD ARCTIC AIR MASS DROPS INTO THE CENTRAL US AND INTO THE OHIO VALLEY EARLY NEXT WEEK. AS MENTIONED EARLIER IF AN SNOW COVER ON THE GROUND DURING THIS PERIOD...MAY SEE TEMPS APPROACH ZERO FOR LOWS...WILL NOT ADJUST THAT WAY AS OF NOW...BUT HAVE TRENDED COLDER THRU THE PERIOD. -SCHOTT && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 240 AM EST TUE JAN 30 2007 .SHORT TERM (TODAY-TONIGHT)... CLIPPER SHORT WAVE MOVING ESE THROUGH IOWA INTO IL/IN ATTM...WITH ASSOC SFC TROF/FRONT STRETCHING FROM NEAR IND TO PAH AS OF 6Z. MOISTURE POOLING ALONG THE FRONT...WITH DEWPOINTS RISING INTO THE MID 20S. SCT SHSN HAVE DEVELOPED ALONG/AHEAD OF THE SFC FRONT...WITH A FEW MOVING INTO THE LMK CWA AND AS FAR S AS NEAR LEITCHFIELD. RECENT ACARS DATA AT KSDF SHOW VERY STEEP LAPSE RATES TO 700MB... HELPING PROMOTE THIS PRECIP. EXPECT ISLTD-SCT SHSN TO REMAIN POSSIBLE THROUGH THE MORNING HOURS...WITH HIGHEST CHCS OVER THE N 1/2 OF THE CWA...DECREASING SOUTHWARD. ANY SNOW AMTS SHOULD BE MINOR AT BEST THOUGH SOME OF THE SHSN HAVE BEEN INTENSE OVER IL/IN/OH BASED ON RADAR REFLECTIVITIES NEAR 35DBZ OR HIGHER...SO IF SOME OF THESE WERE TO AFFECT OUR CWA THERE COULD BE LOCALIZED ACCUMS OF A COUPLE TENTHS OF AN INCH IN A SHORT PERIOD OF TIME. WILL CONTINUE TO MONITOR AS WE GET CLOSER TO THE MORNING DRIVE. BASED ON NAM/RUC...SFC FRONT WILL PASS THROUGH WRN COUNTIES AROUND 10-12Z...INTO ERN/SRN COUNTIES 12-14Z TIMEFRAME. THIS WILL BRING A ROUND OF GUSTY W/NW WINDS TODAY. BUFKIT DIAGNOSTICS INDICATE GUSTS TO 20-25KTS POSSIBLE AND THIS SEEMS REASONABLE BASED ON UPSTREAM OBSERVATIONS. THIS WILL ALSO BRING STEADY OR FALLING TEMPS (EXCEPT PERHAPS THE FAR SE COUNTIES). HAVE FOLLOWED A RUC/NAM BLEND FOR TEMPS TODAY INTO TONIGHT. CHANCES FOR SHSN WILL CONTINUE INTO THE AFTN WITH STEEP LAPSE RATES...THOUGH FEEL THAT OVERALL THREAT WILL BE LOWER THAN IN THE MORNING DUE TO SIGNIFICANTLY DRIER AIR ADVECTING INTO THE LOWER OHIO VALLEY. DEWPOINTS WILL LIKELY FALL INTO THE SINGLE DIGITS THIS AFTN. WILL WORD AFTERNOON POPS AS CHANCE VERSUS MORNING COVERAGE WORDING. GUSTY WINDS WILL LIGHTEN AFTER SUNSET...THOUGH BEFORE THAT OCCURS WIND CHILL VALUES THIS AFTN INTO THE EARLY EVENING WILL LIKELY DROP INTO THE SINGLE DIGITS WITH A FEW NEAR-ZERO VALUES POSSIBLE. HAVE ALLOWED SKIES TO CLEAR OVERNIGHT...THOUGH DID NOT GO WITH COMPLETE CLEARING SINCE NAM AND TO A LESSER EXTENT GFS SUGGEST AN AREA OF 3-5KFT CLOUDS SWEEPING ACROSS THE CWA BETWEEN 6-9Z/WED (OVERNIGHT). CS .LONG TERM (WEDNESDAY-MONDAY)... ...ACTIVE WEATHER PERIOD WITH POTENTIAL FOR ACCUMULATING SNOWS LATE WED THROUGH THURSDAY NIGHT... WEDNESDAY THROUGH FRIDAY NIGHT... FAIRLY ACTIVE AND CHALLENGING FORECAST PERIOD APPEARS TO BE IN STORE FOR THIS PART OF THE FORECAST PERIOD. LATE EVENING MODELS CONTINUE TO BE IN GENERAL AGREEMENT WITH SOUTHWESTERN U.S. UPPER LEVEL WAVE EJECTING EASTWARD DURING THE PERIOD. ALL THE MODELS INDUCE SFC CYCLOGENESIS ACROSS THE DEEP SOUTH AND BRING A SFC LOW EASTWARD ACROSS THE NORTHERN GULF STATES. THE PAST FEW RUNS OF THE MODELS HAVE BEEN TRENDING NORTHWARD WITH THE TRACK OF THE SFC LOW ACROSS THE SOUTHEAST U.S. WE STILL HAVE TWO CAMPS OF TRACKS TONIGHT...WITH THE CANADIAN GLOBAL AND NAM-WRF BEING THE FARTHEST NORTH WITH THE LOW COMING ACROSS THE FA...WHILE THE UKMET AND EURO ARE FURTHER SOUTH. THE 00Z OP GFS IS BETWEEN THESE TWO CAMPS AND OFFERS A PRETTY GOOD COMPROMISE. USING A CONSENSUS OF THE MODEL DATA...WEDNESDAY WILL GENERALLY BE A DRY DAY WITH MID-HIGH LEVEL CLOUDS INCREASING FROM WEST TO EAST. ISENTROPIC UPGLIDE WILL INCREASE WEDNESDAY EVENING AS SFC LOW BEGINS ITS TREK TOWARDS THE NORTHEAST. ANTECEDENT DRY AIRMASS WILL TAKE SOME TIME TO MOISTEN UP WEDNESDAY NIGHT SO PRECIPITATION MAY NOT START UNTIL LATE WEDNESDAY NIGHT. NONETHELESS...IT DOES APPEAR PRECIPITATION WILL BE LIKELY AND THUS HAVE INCREASED POPS TO LIKELY FOR THIS PERIOD. MODEL PROFILES FROM THE GFS SUGGEST ALL SNOW AS THE PRECIPITATION TYPE FOR WEDNESDAY NIGHT. MAIN BULK OF PRECIPITATION WILL FALL ON THURSDAY AS ISENTROPIC LIFT AND FRONTOGENETICAL FORCING WILL BE MAXIMIZED OVER KENTUCKY. BANDED PRECIPITATION WILL LIKELY LIFT NORTHWARD THROUGH THE DAY AND BE ORIENTED ALONG THE OHIO RIVER BY EVENING. HAVE GONE WITH LIKELY POPS HERE BUT PRECIPITATION TYPE WILL BE CHALLENGING. IN THE PAST SEVERAL EVENTS...WE HAVE SEEN STORMS SYSTEMS OUT IN THE LONG RANGE BEING FORECAST TO GO SOUTH...ONLY TO SEE A NORTHWARD TRACK VERIFY AS THE EVENT CAME CLOSER/UNFOLDED. IN ADDITION...THE NUMERICAL MODELS HAVE HAD A TOUGH TIME ESTIMATING THE AMOUNT OF WARM AIR ADVECTING IN ALOFT...WHICH HAS RESULTED IN MORE LIQUID PRECIPITATION OCCURRING. TONIGHT...WE ARE IN THE SAME DILEMMA. BASED ON ALL THE AVAILABLE DATA...AND NOT COMPLETELY THROWING OUT THE NAM-WRF...AM INCLINED TO LEAVE A MIX OF RAIN/SLEET/SNOW IN ACROSS THE SOUTHERN FA SOUTH OF A LINE FROM NEAR HARTFORD TO JUST SOUTH OF RICHMOND. NORTH OF THAT LINE...FEEL THAT DOMINANT PRECIPITATION TYPE WILL BE SNOW. AS SFC LOW HEADS EAST THU NIGHT...SHOULD SEE ALL AREAS GO TO SNOW. ACCUMULATIONS OF SNOW APPEAR LIKELY AT THIS TIME WITH TWO TO FOUR INCHES ACROSS THE NORTHERN HALF OF THE FA WITH ONE TO TWO ACROSS SOUTHERN KY. HOWEVER...IF THE NORTHWARD TREND IN THE SURFACE TRACK OCCURS...LESS SNOW WILL BE LIKELY IN THE SOUTH AND THE 2-4 INCH BAND WOULD BE DISPLACED FURTHER NORTH...PROBABLY NORTH OF THE OHIO RIVER. GIVEN THIS EVENT IS SOME 60-72 HORUS...WILL ISSUE A SPECIAL WX STMT THIS MORNING HIGHLIGHT IMPACTS OF THE EVENT. SNOW WILL LIKELY CONTINUE THURSDAY NIGHT AND DIMINISH SOME BY FRIDAY. SECONDARY CLIPPER TYPE SYSTEM IS FORECAST TO SWING THROUGH THE REGION FRIDAY AFTERNOON AND EVENING AND MAY BRING ANOTHER ROUND OF SNOW SHOWERS TO THE REGION. THUS...HAVE PRETTY MUCH LEFT ONGOING FORECAST INTACT FOR FRIDAY AND FRIDAY NIGHT. AS FOR TEMPERATURES THROUGH THE PERIOD...GENERALLY FOLLOWED A BLEND OF OP GFS RAW SFC TEMPS WITH A SPLASH OF THE MOS STAT GUIDANCE. JARVIS FORECAST FROM SATURDAY ONWARD WAS LEFT AS IS...PREVIOUS FORECAST DISCUSSION FOLLOWS... WILL STAY CLOSE TO THE EURO THROUGH THE PERIOD...WITH SOME SUPPORT FROM THE GFS THROUGH THIS PERIOD AS WELL. INDICES (PNA/EPO/AO) STILL SUPPORT THE COLDER AIR TO CONTINUE TO REPLENISH ITSELF THROUGH THE NEXT FEW WEEKS. DEEP LONGWAVE TROUGH EXTENDS FROM HUDSON BAY POLAR VORTEX(PV) ROTATING FROM THE MS VALLEY THROUGH THE OHIO VALLEY OVER THE WEEKEND...WITH POSSIBLY THE COLDEST AIR OF THE WINTER TO DATE IN THIS PERIOD. SFC HI PRESSURE MOVES ACROSS THE REGION SATURDAY INTO SUNDAY...WEAK CLIPPER STILL LOOKS POSSIBLE SUNDAY EVENING INTO EARLY MONDAY BEFORE ANOTHER VERY COLD ARCTIC AIR MASS DROPS INTO THE CENTRAL US AND INTO THE OHIO VALLEY EARLY NEXT WEEK. AS MENTIONED EARLIER IF AN SNOW COVER ON THE GROUND DURING THIS PERIOD...MAY SEE TEMPS APPROACH ZERO FOR LOWS...WILL NOT ADJUST THAT WAY AS OF NOW...BUT HAVE TRENDED COLDER THRU THE PERIOD. -SCHOTT && .AVIATION (06Z TAFS)... FOCUS FOR THE NEXT 6-12 HOURS IN THE TAFS CENTERS ON CHCS FOR SNOW SHOWERS ALONG WITH WIND SHIFT AS CLIPPER/COLD FRONT PASSES THROUGH THE REGION. AREA RADARS SHOW SCT SHSN OVER IL/IN...BASED ON TRENDS AND LATEST RUC/NAM DATA...A FEW OF THESE MAY AFFECT LEX/SDF TAF SITES THROUGH 15Z...THOUGH COVERAGE WILL LIKELY BE ISLTD SUCH THAT WE WILL NOT CARRY A PREVAILING SHSN GROUP IN THE TAFS...WILL RATHER HANDLE WITH TEMPOS AS NEEDED. CIGS OVER THE REGION ARE NOT TERRIBLY LOW (GENERALLY MVFR-VFR) AND PLAN ON CONTINUING THAT BASED ON FCST SOUNDINGS. SOME CIGS CLOSE TO 1-1.5KFT AGL MAY DROP INTO SRN IND AND PARTS OF CNTRL KY NORTH OF I-64 BETWEEN 12-15Z (PER NAM)...BUT WILL NOT MENTION THOSE IN THE TAFS AT THIS TIME. WINDS WILL SHIFT TO THE W/NW AS COLD FRONT PUSHES THROUGH THE AREA THIS MORNING (11-14Z TIMEFRAME). WHEN THIS HAPPENS WINDS WILL GET GUSTY (GUSTS TO 20-23KTS OR SO) FOR THE BALANCE OF THE DAYLIGHT HOURS. CS && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1210 AM EST TUE JAN 30 2007 .AVIATION (06Z TAFS)... FOCUS FOR THE NEXT 6-12 HOURS IN THE TAFS CENTERS ON CHCS FOR SNOW SHOWERS ALONG WITH WIND SHIFT AS CLIPPER/COLD FRONT PASSES THROUGH THE REGION. AREA RADARS SHOW SCT SHSN OVER IL/IN...BASED ON TRENDS AND LATEST RUC/NAM DATA...A FEW OF THESE MAY AFFECT LEX/SDF TAF SITES THROUGH 15Z...THOUGH COVERAGE WILL LIKELY BE ISLTD SUCH THAT WE WILL NOT CARRY A PREVAILING SHSN GROUP IN THE TAFS...WILL RATHER HANDLE WITH TEMPOS AS NEEDED. CIGS OVER THE REGION ARE NOT TERRIBLY LOW (GENERALLY MVFR-VFR) AND PLAN ON CONTINUING THAT BASED ON FCST SOUNDINGS. SOME CIGS CLOSE TO 1-1.5KFT AGL MAY DROP INTO SRN IND AND PARTS OF CNTRL KY NORTH OF I-64 BETWEEN 12-15Z (PER NAM)...BUT WILL NOT MENTION THOSE IN THE TAFS AT THIS TIME. WINDS WILL SHIFT TO THE W/NW AS COLD FRONT PUSHES THROUGH THE AREA THIS MORNING (11-14Z TIMEFRAME). WHEN THIS HAPPENS WINDS WILL GET GUSTY (GUSTS TO 20-23KTS OR SO) FOR THE BALANCE OF THE DAYLIGHT HOURS. CS && .UPDATE... DOING A QUICK UPDATE TO ADD MENTION OF ISLTD -SHSN FOR SRN INDIANA OVERNIGHT. AREA OF SNOW SHOWERS OVER IL/IN WILL AFFECT NRN SECTIONS OF OUR CWA OVERNIGHT AS UPPER LEVEL SHORTWAVE DROPS SE FROM IA INTO IL. WILL ALSO INCREASE CLOUD COVER ACCORDINGLY...AND ADD MENTION OF FLURRIES FOR THE LOU/LEX VICINITIES. CS && .SHORT TERM (TONIGHT AND TUESDAY)... LONG LOOP WATER VAPOR PICTURES INDICATE YET ANOTHER CLIPPER TYPE SYSTEM DROPPING THROUGH THE UPPER MISSISSIPPI VALLEY THIS AFTERNOON. TEMPERATURE HAVE SURGED INTO THE UPPER 20S AND LOWER 30S AHEAD OF A COLD FRONT LOCATED ACROSS ILLINOIS AND MISSOURI. THIS FRONT WILL SWEEP ACROSS THE FORECAST AREA BETWEEN 9-15Z TUESDAY. IN THE WAKE OF THE FRONT STEEP LAPSE RATES WILL PRODUCE ISOLATED TO SCATTERED SNOW SHOWERS. PRECIPITATION SHOULD BE LESS THAN SUNDAY MORNING AS THE ATMOSPHERE IS VERY DRY BUT A FEW LOCATIONS ACROSS THE BLUEGRASS REGION MAY SEE UP TO A HALF INCH OF SNOW IN HEAVIER SHOWERS. COLD AIR WILL ADVECT INTO THE AREA TUESDAY AFTERNOON AND I HAVE GONE SEVERAL DEGREES BELOW MOS HIGHS TUESDAY WITH THE WARMEST TEMPERATURES OCCURING IN THE MORNING AND FALLING TEMPERATURES DURING THE AFTERNOON. FOR TONIGHT WE WILL SEE PARTLY CLOUDY SKIES AND WESTERLY WINDS. MOS TEMPERATURES FOR THIS PERIOD LOOK GOOD. --JA .LONG TERM (TUESDAY NIGHT THROUGH MONDAY)... TUESDAY NIGHT THROUGH WEDNESDAY... GREAT CONFIDENCE IN THIS PERIOD AS NEARLY UNANIMOUS SOLUTION AMONG THE SHORT RANGE MODELS. WILL USED THE 09Z SREF AS A BASIS FOR THE FORECAST AND HOURLY GRIDS...THOUGH LITTLE IF ANY CHANGE FROM PREVIOUS FORECAST. TUESDAY NIGHT SHORTWAVE TROUGH WILL BE EXITING ACROSS THE APPALACHIANS AS LARGE AREA OF SFC HI PRESSURE WORKS EAST INTO THE OHIO VALLEY. BEHIND THE TROUGH ANOTHER REINFORCING SHOT OF COLDER AIR. SFC HI PRESSURE MOVES ACROSS THE REGION WEDNESDAY...SOME HIGH CLOUDS WILL START TO STREAM ACROSS THE SKIES DURING THE AFTERNOON INTO THE EVENING HOURS AHEAD OF DEVELOPING SOUTHERN SYSTEM. LOWS WEDNESDAY MORNING WILL DROP INTO THE LOWER TO MIDDLE TEENS. THURSDAY AND FRIDAY... AS MENTIONED YESTERDAY...THESE TWO DAYS ARE THE BIGGEST CHALLENGE IN THE FORECAST THROUGH THE NEXT WEEK DUE TO JUMPY MODELS AND THE ALWAYS PRESENT POSSIBILITY THAT MODELS ARE UNDERPLAYING THE STRENGTH OF SOUTHERN FLOW AHEAD OF THE SYSTEM AND CONTAIN A COLD BIAS ALOFT...THIS ESPECIALLY GOES FOR THE GFS. ONE THING THAT DOES ADD MUCH MORE CONFIDENCE TO THE FORECAST AS A WHOLE IS THE SOLUTIONS HAVE CONVERGED SOMEWHAT FOR EACH DAY...ESPECIALLY THE 12Z ECMWF AND 12Z GFS RUNS FROM TODAY. THEREFORE WILL USE A BLEND OF THE TWO FOR THIS 48 HOUR PERIOD. THE CANADIAN IS NOT TOO FAR OFF BUT HAS A SLIGHTLY WEAKER SOLUTION...BUT THE UKMET DOES LEND SOME SUPPORT TO THE BLENDED SOLUTION ALLOWING FOR SLIGHTLY INCREASED CONFIDENCE OF THEIR SOLUTIONS. EARLY THURSDAY...ISENTROPIC LIFT IS VERY APPARENT IN BOTH THE GFS AND THE NAM THRU EARLY AFTERNOON...ESPECIALLY IN THE 280 TO 290K SURFACES...AS WELL AS MOISTURE TRANSPORT INTO THE REGION. SOME UNCERTAINTY WILL EXIST TO HOW LONG IT TAKES FOR THE VERY DRY LOW LEVELS TO MOISTEN UP...WOULD THINK THAT NO PRECIP SHOULD REACH GROUND UNTIL THE EARLY MORNING HOURS...MAINLY AFTER 1AM TO 4AM ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA...SPREADING EAST AFTER 7AM. MODEST FRONTOGENETICAL FORCING ACROSS THE REGION...WHICH WOULD BE MAXIMIZED ACROSS THE SOUTHERN PORTIONS OF THE FORECAST AREA THURSDAY MORNING...THEN ACROSS THE ENTIRE AREA EAST OF I-65 FROM THE LATE MORNING INTO THE AFTERNOON. ALONG WITH A 130 TO 140KT JET STREAK PASSING ACROSS THE MID OHIO VALLEY DURING THE MORNING INTO THE AFTERNOON THURSDAY. ALL TOGETHER IT MEANS A DECENT SHOT A SOME ACCUMULATING SNOW ACROSS THE FORECAST AREA...CURRENTLY THE HIGHEST POSSIBLE ACCUMS LOOK TO BE ACROSS THE SOUTHERN PORTIONS OF THE AREA SOUTH OF A LINE FROM HARTFORD TO RICHMOND. FORECAST SOUNDINGS INDICATE THE DOMINATE PRECIP TYPE TO BE SNOW...THOUGH AS MENTIONED EARLIER WILL HAVE TO WATCH FOR TREND OF STRONGER SW WINDS ALOFT WHICH MAY CREATE MORE OF A MIX ACROSS SOUTH CENTRAL KENTUCKY. AS USUAL AT 3 DAYS OUT OR MORE SOME CHANGES IN TRACK CAN BE EXPECTED IF THE TRACK SHIFTS SLIGHTLY FURTHER NORTH THEN MORE MOISTURE MAY BE BROUGHT INTO THE REGION AND BETTER CHANCES FOR MORE SNOW...LIQUID EQUIV CURRENTLY SUGGEST THAT SOUTHERN KY MAY SEE 1 TO 3 INCHES IF NO MIX WERE TO OCCUR...WITH AROUND AN INCH NORTH OF THERE AT THIS TIME. ENOUGH COLD AIR SHOULD BE IN PLACE ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA SO A MIX IS VERY UNLIKELY AS FORECAST SOUNDINGS ALOFT NEVER WARM HIGHER THAN -2C DUE TO THE LOW LEVEL JET. HAVE UNDERCUT MOS TEMPS HERE WITH EVAP COOLING AND CLOUDS/PRECIP IN PLACE DURING THE PEAK HEATING HOURS. FRIDAY IS A DIFFERENT STORY WITH RESPECT TO CONFIDENCE...THOUGH THE MODELS HAVE CLOSED SOMEWHAT ON A SOLUTION. STILL MUCH MORE UNCERTAINTY HERE THAN ON THURSDAY. GFS LOOKS ODD...IF YOU USE THE HIGHER RESOLUTION VERSION SAY 40KM...PULL BACK TO THE 90KM VERSION AND IT LOOKS MUCH LIKE THE 12Z EURO SOLUTION. OVERALL LESSER CHANCES FOR ACCUMS ON FRIDAY BUT STILL A CHANCE FOR LIGHT SNOW AS A FRONT WILL SWING THRU THE REGION DURING THE MORNING OR AFTERNOON. MODEST FRONTOGENETICAL FORCING SEEN THROUGH EARLY AFTERNOON AND STRONG JET STREAK MAY HELP WITH LIFT...ONLY CONCERN LOOKS TO BE MOISTURE SO HAVE LOWERED POPS TO 30 ACROSS THE REGION. TEMPERATURES WILL START TO TUMBLE FROM FRIDAY INTO THE WEEKEND AS ARCTIC AIR WORKS ACROSS THE REGION. IF ANY SIGNIFICANT SNOWCOVER EXISTS THEN WE WILL HAVE TO LOWER TEMPERATURES FROM FRIDAY THRU THE EARLY PORTIONS OF NEXT WEEK. SATURDAY INTO EARLY NEXT WEEK... WILL STAY CLOSE TO THE EURO THROUGH THE PERIOD...WITH SOME SUPPORT FROM THE GFS THROUGH THIS PERIOD AS WELL. INDICES (PNA/EPO/AO) STILL SUPPORT THE COLDER AIR TO CONTINUE TO REPLENISH ITSELF THROUGH THE NEXT FEW WEEKS. DEEP LONGWAVE TROUGH EXTENDS FROM HUDSON BAY POLAR VORTEX(PV) ROTATING FROM THE MS VALLEY THROUGH THE OHIO VALLEY OVER THE WEEKEND...WITH POSSIBLY THE COLDEST AIR OF THE WINTER TO DATE IN THIS PERIOD. SFC HI PRESSURE MOVES ACROSS THE REGION SATURDAY INTO SUNDAY...WEAK CLIPPER STILL LOOKS POSSIBLE SUNDAY EVENING INTO EARLY MONDAY BEFORE ANOTHER VERY COLD ARCTIC AIR MASS DROPS INTO THE CENTRAL US AND INTO THE OHIO VALLEY EARLY NEXT WEEK. AS MENTIONED EARLIER IF AN SNOW COVER ON THE GROUND DURING THIS PERIOD...MAY SEE TEMPS APPROACH ZERO FOR LOWS...WILL NOT ADJUST THAT WAY AS OF NOW...BUT HAVE TRENDED COLDER THRU THE PERIOD. SCHOTT && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 958 PM CST WED JAN 31 2007 .DISCUSSION... AREAS OF RAIN...POSSIBLY MIXED WITH A FEW IP/S...CONTINUES ACROSS NORTHCENTRAL/NE LA THIS EVENING...MAINLY IN ASSOCIATION OF STRONG ISENTROPIC ASCENT ALONG THE 295-305K SURFACES. HOWEVER...IP THREAT WILL BE SHORT LIVED HERE AS 00Z KSHV RAOB INDICATES THAT WEAK WARM ADVECTION HAS WARMED/MOISTENED THE AIR COLUMN ENOUGH BELOW 9KFT SUCH THAT EVAPORATIVE COOLING IS NO LONGER BECOMING AN ISSUE FOR IP FORMATION. FARTHER N...SN/IP HAS TAPERED THIS EVENING AS ISENTROPIC FORCING ALONG THE 295K SURFACE HAS SHIFTED E OF THE REGION. BELIEVE THE REST OF THE NIGHT WILL BE SOMEWHAT QUIET...UNTIL MAIN SHORTWAVE ENERGY APPROACHES THE REGION FROM THE W...IN ASSOCIATED WITH THE MERGING OF THE BAJA LOW WITH THE NEXT SHORTWAVE ROUNDING THE N STREME JET. NAM/RUC SOUNDINGS INDICATE A WARM NOSE DEVELOPING AROUND 3500FT ACROSS SW/SOUTHCENTRAL AR /TXK AND ELD/...SUCH THAT FROZEN HYRDROMETEORS WILL MELT ENOUGH FOR A RAIN/IP MIX. HOWEVER...EXPECTING TEMPS TO REMAIN JUST ABOVE FREEZING OVERNIGHT AT TXK...THUS HAVE CANCELLED THE WINTER ADV. FOR BOWIE AND MILLER COUNTIES. ALTHOUGH TEMPS WILL REMAIN NEAR FREEZING AT ELD. HOWEVER...HAVE ENOUGH CONFIDENCE IN KEEPING A WINTER WX ADVISORY OUT OF ELD FOR NOW...AS THE WINTRY MIX SHOULD AWAIT UNTIL AFTER 12Z THURSDAY. EVEN FORECATS SOUNDINGS HERE SUPPORT CONSIDERABLE WARM NOSING AFTER 6Z AND THEREAFTER...SUCH THAT ANY RAIN THAT FALLS THROUGH THE WARMER AIR WILL TEND TO SLIGHTLY WARM SURFACE TEMPS/DEWPOINTS. HOWEVER...WILL ADDRESS LEFTOVER WATER/ADDITIONAL LIGHT PRECIP. THAT OCCURS TONIGHT IN AN SPS FOR THIS AREA...AS WELL AS A COUPLE OF N LA PARISHES...AS RAWS REPORTS INDICATE THEM NEAR FREEZING AS WELL. ELSEWHERE...FORECAST SOUNDINGS SUPPORT A MIX OF SN/IP MIX LATE ACROSS RED RIVER...MCCURTAIN...SEVIER AND HOWARD COUNTIES WITH THE NEXT SHORTWAVE APPROACHING...BUT ADDITIONAL SNOW/ICE ACCUMULATIONS THROUGH 12Z WILL BE LIGHT. THUS...HAVE OPTED TO RETAIN THE WINTER ADV. FOR THESE AREAS...AS WELL AS HEMPSTEAD/NEVADA COUNTIES AS THESE AREAS WILL REMAIN NEAR/BELOW FREEZING. TOUGH CALL IN TERMS OF HOW LONG THESE AREAS WILL SUPPORT FROZEN PRECIP. THURSDAY...AS WARM ADVECTION REGIME CONTINUES...ALTHOUGH FAR NW COUNTIES MAY SEE MIXED WINTRY PRECIP. FOR MUCH OF THE DAY. WARM ADVECTION MAY CHANGEOVER PRECIP. TO RAIN BY MIDDAY/EARLY AFTERNOON OVER HEMPSTEAD/NEVADA COUNTIES...BUT WILL LET THE MID SHIFT ADDRESS THIS ISSUE. COULD STILL SEE 1-3" OF SNOW ACROSS N MCCURTAIN COUNTY AND POSSIBLY SEVIER/HOWARD COUNTIES BEFORE THE PRECIP. WANES LATE THURSDAY...WITH ICE ACCUMULATIONS OF ONE TENTH TO ONE QUARTER OF AN INCH ELSEWHERE IN THE ADVISORY AREA...BUT THIS WILL BE HIGHLY DEPENDENT ON AMOUNT OF WARMING /ABOVE FREEZING/ THROUGH THE DAY. IN ALL...ADJUSTED POPS TONIGHT DOWN EXCEPT WHERE PRECIP. LINGERS CURRENTLY. ALSO TOOK OUT FROZEN PRECIP. MENTION THURSDAY MORNING ACROSS E TX/N LA S OF I-20...AND MADE MINOR TWEAKS TO THE MIN TEMPS GRIDS TONIGHT...WITH LITTLE CHANGE/SLOW WARMING EXPECTED OVERNIGHT. OTHERWISE...REMAINDER OF THE FORECAST IS IN GOOD SHAPE. UPDATED FORECAST/WSW ALREADY OUT...SPS WILL BE ISSUED SHORTLY. 15 && .AVIATION... A LARGE AREA OF RAIN MIXED WITH ISOLATED AREAS OF LIGHT SLEET WILL COVER MUCH OF DEEP EAST TEXAS ACROSS LOWER PARTS OF NORTHWEST LOUISIANA INTO NORTH CENTRAL LOUISIANA AND SOUTHEAST ARKANSAS. LUCKILY TEMPERATURES WITHIN THIS LARGE AREA REMAIN AND SHOULD REMAIN BELOW FREEZING KEEPING THE PRECIPITATION LIQUID...WITH JUST A FEW SLEET PELLETS. LOW LEVEL WARM ADVECTION SHOULD ALLOW MOST OF THE MIXED PRECIPITATION TO BECOME MOSTLY RAIN OVER DEEP E TX AND ACROSS LA BY LATE TONIGHT. THIS RAIN AREA WILL ALSO DECREASE IN AREAL COVERAGE BY 01/12Z. MOST PRECIPITATION HAS ENDED OVER NORTHEAST TEXAS INTO SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA. CEILINGS THIS EVENING HAVE BEEN RANGING FROM AROUND 1 KFT TO 2.5 KFT FOR MUCH OF THE FOUR STATE REGION...WITH CEILINGS ACROSS DEEP EAST TEXAS ACROSS LOWER SECTIONS OF NORTHWEST AND INTO LOWER NORTH CENTRAL LOUISIANA RANGING FROM NEAR 4 HND TO 8 HND FEET. VISIBILITIES HAVE BEEN GTE 6 STATUE MILES EXCEPT IN THE HEAVIER RAIN AREAS WHERE THEY HAVE LOWERED TO 1 TO 3 STATUE MILES. AFTER 01/06Z TOWARD 01/12Z EXPECTING ANOTHER ROUND OF RAIN TO RETURN AS A SURFACE LOW PRESSURE SYSTEM SLIDES EAST ACROSS THE GULF OF MEXICO AND HIGH PRESSURE CENTERED ALONG THE COAST OF THE CAROLINAS SHIFTS EAST. ANOTHER LOW OVER W TX WILL ADVANCE EAST. ABUNDANT MOISTURE RIDING OVER THE FOUR STATE REGION WILL PRODUCE RAIN AND A WINTERY MIX ESPECIALLY OVER PARTS OF NE TX...SE OK...AND SW AR NEAR AND ALONG THE INTERSTATE 30 CORRIDOR WITH MOSTLY RAIN ALONG AND NEAR THE INTERSTATE 20 CORRIDOR. AFTER 01/12Z RAIN WILL BE INCREASING AND SPREADING AREA WIDE WITH CEILINGS FROM 4 TO 8 HND FEET. IN THE COLDER AREAS THERE WILL BE A MIX OF SNOW...SLEET...AND WITH EARLY START MIX OF FREEZING RAIN NEAR INTERSTATE 30. /06/ && .PRELIMINARY POINT TEMPS/POPS... SHV 35 41 35 45 / 40 90 20 10 MLU 34 40 36 48 / 80 90 20 10 DEQ 29 36 28 42 / 50 90 20 10 TXK 33 37 31 44 / 50 90 20 10 ELD 32 39 32 46 / 40 90 20 10 TYR 36 42 34 45 / 50 90 10 10 GGG 35 43 34 45 / 50 90 10 10 LFK 39 46 38 50 / 70 90 10 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...WINTER WEATHER ADVISORY UNTIL 4 PM THURSDAY FOR THE FOLLOWING ZONES: HEMPSTEAD...HOWARD...LITTLE RIVER...NEVADA...AND SEVIER. LA...NONE. OK...WINTER WEATHER ADVISORY UNTIL 4 PM THURSDAY FOR THE FOLLOWING ZONES: MCCURTAIN. TX...WINTER WEATHER ADVISORY UNTIL 4 PM THURSDAY FOR THE FOLLOWING ZONES: RED RIVER. && $$ 15/06 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 208 PM EST TUE JAN 30 2007 .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... RUC AND NAM-WRF SHOW THAT THE COLD FRONT ASSOCIATED WITH THE CLIPPER-TYPE LOW PRESSURE SYSTEM WILL HAVE MOVED THROUGH THE UPPER OHIO VALLEY BY EVENING. HENCE, TONIGHT THE UPPER OHIO VALLEY WILL BE MAINLY AFFECTED BY POSTFRONTAL COLD-ADVECTION LIFT/INSTABILITY AND LAKE-ENHANCED SNOW SHOWERS. THIS WILL GENERATE SNOW ACCUMULATIONS ON THE ORDER OF AN INCH FOR MOST PLACES, BUT AS MUCH AS 3 INCHES NEAR THE MOUNTAINS AND ALONG THE INTERSTATE 80 CORRIDOR. BASED ON NAM-WRF FORECAST SOUNDINGS, EXPECT THE UNSTABLE BOUNDARY LAYER TO SHRINK TO A HEIGHT OF LESS THAN 6 KFT AGL AFTER MIDNIGHT. THEREFORE, THE PRECIPITATION WILL DIMINISH TO MAINLY FLURRIES BY WEDNESDAY DAYTIME. SO WILL KEEP ENDING TIME OF CURRENT SNOW/LAKE SNOW ADVISORIES AS IS. FOR TEMPERATURES, WILL KEEP WITH RECENT NAM AND GFS MOS VALUES. WINDS WILL BE MAINLY WESTERLY INTO WEDNESDAY AT 10 TO 15 MPH, ALBEIT SOME GUSTS CAN BRIEFLY REACH 20-25 MPH. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... RECENT GFS AND ECMWF MODEL RUNS SHOW LITTLE CHANGE IN THE CURRENT UPPER FLOW PATTERN OVER NORTH AMERICA OVER THE NEXT WEEK, AND PERHAPS INTO MID FEBRUARY, WITH A CLOSED UPPER LOW OVER EASTERN CANADA PROVIDING A CYCLONIC NORTHWEST FLOW ACROSS THE GREAT LAKES AND UPPER OHIO VALLEY. SO THE CURRENT EPISODE OF COLDER THAN NORMAL TEMPERATURES AND ACCOMPANYING CLIPPER-RELATED PERIODS OF LIGHT BUT PESKY SNOW SHOWERS WILL BE THE RULE INTO NEXT WEEK. IT DOES APPEAR THE START OF NEXT WEEK WILL BE COLDER THAN THIS WEEK AS 850MB TEMPERATURES WILL BE FREQUENTLY COLDER THAN M20C AND SURFACE TEMPERATURES WILL BE MAINLY IN THE ZERO TO 15 ABOVE RANGE AS INDICATED BY RECENT HPC GUIDANCE AND GFS MOS VALUES. && .AVIATION /19Z-18Z/... COLD FRONT IS CROSSING PITTSBURGH AT THE MOMENT BRINGING A BAND OF HEAVIER SNOW SHOWERS. SNOW SHOWERS ARE KEEPING CONDITIONS IN THE IFR RANGE WITH VISIBILITIES AROUND 2SM OR LOWER. CEILINGS ARE GENERALLY MVFR RANGING FROM 1000 TO 2000 FEET. THESE CONDITIONS SHOULD CONTINUE THROUGH THE NIGHT EXCEPT FOR THE VISIBILITIES IMPROVING TO MVFR OR VFR OVERNIGHT AS THE SNOW SHOWERS MOVE IN AND OUT OF THE AIRPORT AREAS AND DECREASE IN COVERAGE BY DAYTIME WEDNESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MDZ001. OH...NONE. PA...SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR PAZ030-032. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR PAZ007>009. WV...SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR WVZ023-041. && $$ 66/11/66/ md AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1248 PM EST TUE JAN 30 2007 .MARINE... WNDS ABV SCA CRITERIA AT TPLM2...AND GUSTS ARND 20 KT REPORTED AT ERN MTR SITES. SEEMS THO SUFFICIENT MIXING TAKING PLACE IN SPITE OF IMPENDING CLDCVR AND COLD WATER. WL RAISE FLAGS NOW...AND FIRE OFF A QUICK MARINE UPDT. && .AVIATION /18Z-18Z/... VFR CONDS WL PREVAIL...W/ CHC -SHSN ALL SITES XCPT CHO LT AFTN INVOF FROPA. SHUD HV LTL TO NO VSBY RESTRICTIONS...AND THUS NO OPERATIONAL IMPACT. SLY FLOW /G20 KT/ WL VEER NW BY 00Z. HIER GUSTS PROBABLE...SPCLY RIGHT BHD FROPA. && .PREV DISCUSSION... /ISSUED 1005 AM EST TUE JAN 30 2007/ SHORT TERM /REST OF TODAY/... VORT MAX CNTRD IN SRN OH ATTM PER VAPOR LOOP. RGNL RADARS DEPICT SHSN HAS SPREAD E OF THAT TO THE WRN RDGS OF CWFA. AFTR GLANCING AT 12Z RUNS OF RUC AND NAM...IT APPRS THAT MOST OF THE DEEP MSTR WL BE CONFINED TO THOSE RDGS. TRACK OF SHEARED VORT WL BE W-E ACRS CWFA...PASSING NEAR OF JUST N OF DC. SFC REFLECTION WL CROSS PA... WELL N OF US. THUS...DONT HV MUCH HOPE THAT SNW WL FALL E OF FVRD UPSLOPE TRRN. GOING FCST CVRS THAT. WL HOLD ONTO SNW ADVY AREA AS THESE ZNS CARRY HIEST RISK. AM A LTL CONCERNED THAT MAXT MAY BE A CPL TICKS TOO HIGH PER MRNG RAOBS. BUT DUE TO AMPLE SUN ATTM AND BRIEF PD OF SW FLOW AHD OF S/WV...WL LV THAT AS IS ALSO. THUS...HV TOUCHED UP A FEW GRIDS...BUT NO UPDT TO TXT PRODUCTS XPCTD ATTM. AVIATION /15Z-12Z/... VFR CONDS THRU PD...W/ 5000 FT CIGS LT TAFTN-ELY EVE. MAYBE A PD OF FLURRIES AT MRB AS CLIPPER PASSES N OF AREA. CUD EVEN BE A FLURRY OR TWO DC-BALT AREA AIRPORTS...BUT RISK TOO SLIM FOR TAF MNTN. SHUD HV NO IMPACT TO OPS. MARINE... LGT SLY FLOW AHD OF CLIPPER SYSTM. WNDS WL VEER NW AND PICK UP TNGT IN WAKE OF SYSTM. WL HOLD ONTO SCA HEADLINE FOR TNGT. PREV DISCUSSION... /ISSUED 320 AM EST TUE JAN 30 2007/ SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... A BIT OF A COMPLEX FORECAST WITH SOME CONFLICTING INFO FROM THE MODELS ABOUT A CLIPPER COMING THROUGH THIS AFTERNOON. THE SFC LOW WAS MOVING THRU THE MIDWEST EARLY THIS MORNING AND PRESSING EAST. IT WILL BE SLOWLY STRENGTHENING AS IT MOVES THROUGH OUR AREA AND OUT OVER THE OCEAN. THE VORT ASSOCIATED WITH IT IS SHEARED VORTICITY MOVING ACROSS THE MID ATL AND NOT A STRONG PACKET SO NOT IMPRESSED WITH SNOWFALL POTENTIAL EAST OF THE MTNS. THERE IS SOME FN VECTR CONVERGENCE BETWEEN 700 AND 500MB THAT EXTENDS S FROM THE VORT MOVING THROUGH LIKE A COLD FRONT DURING THE AFTERNOON. THAT IS ONE INDICATOR THAT A SMALL SNOW BAND COULD MOVE THROUGH IN THE AFTERNOON. HOWEVER WITH THE SHEARED VORT THAT MOVES EAST THRU DC... THE BEST CHC WOULD BE N OF THAT AND WITH THE SHEARED NATURE OF THE SYSTEM... A SLIM CHC EVEN THERE. ALSO HIGH TEMPS TODAY ARE FORECAST ABOVE FREEZING EXCEPT FOR AT ELEVATION... AND CURRENT RADAR EXTENT OF THE SYSTEM IS LIMITED. PUT ALL OF THAT TOGETHER AND THE BEST CHC IS THAT NO MEASURABLE SNOW MAKES IT EAST OF THE MTNS. THERE IS AROUND A 30 PERCENT CHC FOR A DUSTING FOR THE N TIER OF MD... AND AN EVEN SMALLER 10-20 PERCENT CHC OF A DUSTING SOUTH OF THAT. ONCE THE CLIPPER ROLLS THRU... SKIES CLEAR OUT AGAIN AND NW WINDS KICK UP AGAIN BRINGING COLD TEMPS AROUND 20 FOR MANY BY WED MORNING WITH WIND CHILLS BACK DOWN AROUND ZERO IN THE WESTERN MOUNTAINS AND IN THE TEENS AND SINGLE DIGITS FOR THE REST. IN THE WESTERN UPSLOPE AREAS OF W GRANT W MINERAL AND W ALLEGANY COUNTIES THERE WILL BE A SNOW ADV ISSUED FOR THIS AFTERNOON AND OVERNIGHT. 1 TO 3 INCHES WILL LIKELY PILE UP AGAIN AS SNOW SHOWERS RETURN. AVIATION /09Z-12Z/... VFR CONDITIONS EXPECTED THRU THE TAF PERIOD FOR THE MOST PART. MAY BRIEFLY TOUCH MVFR CONDTIONS WHEN THE CLIPPER ACTUALLY MOVES THRU IN THE AFTERNOON... BUT BETTER CHC THAT IT WILL REMAIN VFR. SW WINDS WILL FLIP TO NW AND BECOME GUSTY AGAIN THIS EVENING AND TONIGHT. SNOW SHOWERS IN THE MOUNTAINS WILL BE REFLECTED IN THE TWEBS. THERE IS A SLIGHT CHC OF A CONVECTIVE BAND OF SNOW SHOWERS DEVELOPING ALONG THE CLIPPER...BUT AGAIN A BETTER CHC THAT SNOW SHOWERS WILL NOT MAKE IT EAST OF THE MOUNTAINS. MARINE... AFTER THE CLIPPER LOW MOVES THRU AND STRENGTHENS A LITTLE BIT WINDS WILL KICK UP ONCE AGAIN AND A SMALL CRAFT ADVISORY IS IN PLACE FOR 9 PM TONIGHT THROUGH 10 AM WEDNESDAY. SMALL CRAFT ADVISORY CONDITIONS THIS WEEKEND IN THE WAKE OF THE LOW PRESSURE SYSTEM AFFECTING THE WATERS THURSDAY NIGHT. LONG TERM /WEDNESDAY THROUGH MONDAY/... BUSY MEDIUM RANGE FORECAST WITH A LOW PRESSURE SYSTEM MAKING ITS WAY FROM THE CENTRAL GULF COAST NORTHEAST ACROSS THE MID ATLANTIC STATES THURSDAY NIGHT. HIGH PRESSURE WILL PUSH THIS SYSTEM OUT TO SEA FOR THE WEEKEND...PROVIDING COOL AND DRY CONDITIONS FOR MOST LOCATIONS THROUGH THE END OF THE FORECAST PERIOD. THE EXCEPTION WILL BE CONTINUED CHANCES FOR UPSLOPE SHOWERS WEST OF THE ALLEGANY FRONT. MAIN FORECAST CHALLENGE IS WITH THE SOUTHERN STREAM LOW APPROACHING THURSDAY. MODELS CONTINUE THEIR INCONSISTENCIES WITH THIS SYSTEM FROM TIMING AND LOCATION TO PRECIPITATION TYPE. WHILE THE TRACK OF THE ACTUAL LOW IS STILL UNCERTAIN...BUT GUIDANCE COMES BACK IN LINE WITH THE LOW PLACED OFF THE NORTHERN MID ATLANTIC COAST FRIDAY MORNING AT 12Z. THE ECMWF IS THE FASTER MODEL WHILE THE NAM IS THE SLOWEST AND THE GFS IN BETWEEN. TOOK A BLEND OF THE THREE USING THE GFS. WHILE EARLIER RUNS BROUGHT PRECIPITATION IN FASTER...GUIDANCE HAS SINCE BACKED OFF. EXPECT PRECIPITATION TO SPREAD NORTHEAST ACROSS THE FORECAST AREA THURSDAY AFTERNOON...WITH HIGHEST POPS MOST LIKELY THURSDAY NIGHT. PRECIPITATION TYPES WITH THIS SYSTEM WILL BE INTERESTING TO WATCH OVER THE NEXT DAY OR TWO. WITH THE VARYING TRACKS OF THE LOW...TYPE FORECASTING HAS BEEN MORE OF A CHALLENGE. USING HPC GUIDANCE AND BUFKIT MODEL SOUNDINGS...A CHANGE OVER FROM SNOW TO FREEZING RAIN IS A POSSIBILITY ACROSS THE CENTRAL FORECAST AREA...AND SWITCHING FROM SNOW TO RAIN IN THE FAR NORTHEAST. HAVE ADDED THE MENTION OF SNOW AND FREEZING RAIN TO THE GRIDS FOR WASHINGTON DC WEST TO THE BLUE RIDGE AND SOUTH THROUGH THE SHENANDOAH VALLEY...WITH A RAIN AND SNOW MIX ACROSS BALTIMORE. CONFIDENCE WITH PRECIPITATION TYPE IS LOW GIVEN VARIANCE OF RECENT MODEL RUNS...SO THIS WILL MOST LIKELY CHANGE OVER THE NEXT 24 TO 48 HOURS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MDZ501. VA...NONE. WV...SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR WVZ501-503. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ530>537. && $$ UPDATES...HTS ORIGINAL DISCUSSION...STRONG/SAR md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1005 AM EST TUE JAN 30 2007 .SHORT TERM /REST OF TODAY/... VORT MAX CNTRD IN SRN OH ATTM PER VAPOR LOOP. RGNL RADARS DEPICT SHSN HAS SPREAD E OF THAT TO THE WRN RDGS OF CWFA. AFTR GLANCING AT 12Z RUNS OF RUC AND NAM...IT APPRS THAT MOST OF THE DEEP MSTR WL BE CONFINED TO THOSE RDGS. TRACK OF SHEARED VORT WL BE W-E ACRS CWFA...PASSING NEAR OF JUST N OF DC. SFC REFLECTION WL CROSS PA... WELL N OF US. THUS...DONT HV MUCH HOPE THAT SNW WL FALL E OF FVRD UPSLOPE TRRN. GOING FCST CVRS THAT. WL HOLD ONTO SNW ADVY AREA AS THESE ZNS CARRY HIEST RISK. AM A LTL CONCERNED THAT MAXT MAY BE A CPL TICKS TOO HIGH PER MRNG RAOBS. BUT DUE TO AMPLE SUN ATTM AND BRIEF PD OF SW FLOW AHD OF S/WV...WL LV THAT AS IS ALSO. THUS...HV TOUCHED UP A FEW GRIDS...BUT NO UPDT TO TXT PRODUCTS XPCTD ATTM. && .AVIATION /15Z-12Z/... VFR CONDS THRU PD...W/ 5000 FT CIGS LT TAFTN-ELY EVE. MAYBE A PD OF FLURRIES AT MRB AS CLIPPER PASSES N OF AREA. CUD EVEN BE A FLURRY OR TWO DC-BALT AREA AIRPORTS...BUT RISK TOO SLIM FOR TAF MNTN. SHUD HV NO IMPACT TO OPS. && .MARINE... LGT SLY FLOW AHD OF CLIPPER SYSTM. WNDS WL VEER NW AND PICK UP TNGT IN WAKE OF SYSTM. WL HOLD ONTO SCA HEADLINE FOR TNGT. && .PREV DISCUSSION... /ISSUED 320 AM EST TUE JAN 30 2007/ SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... A BIT OF A COMPLEX FORECAST WITH SOME CONFLICTING INFO FROM THE MODELS ABOUT A CLIPPER COMING THROUGH THIS AFTERNOON. THE SFC LOW WAS MOVING THRU THE MIDWEST EARLY THIS MORNING AND PRESSING EAST. IT WILL BE SLOWLY STRENGTHENING AS IT MOVES THROUGH OUR AREA AND OUT OVER THE OCEAN. THE VORT ASSOCIATED WITH IT IS SHEARED VORTICITY MOVING ACROSS THE MID ATL AND NOT A STRONG PACKET SO NOT IMPRESSED WITH SNOWFALL POTENTIAL EAST OF THE MTNS. THERE IS SOME FN VECTR CONVERGENCE BETWEEN 700 AND 500MB THAT EXTENDS S FROM THE VORT MOVING THROUGH LIKE A COLD FRONT DURING THE AFTERNOON. THAT IS ONE INDICATOR THAT A SMALL SNOW BAND COULD MOVE THROUGH IN THE AFTERNOON. HOWEVER WITH THE SHEARED VORT THAT MOVES EAST THRU DC... THE BEST CHC WOULD BE N OF THAT AND WITH THE SHEARED NATURE OF THE SYSTEM... A SLIM CHC EVEN THERE. ALSO HIGH TEMPS TODAY ARE FORECAST ABOVE FREEZING EXCEPT FOR AT ELEVATION... AND CURRENT RADAR EXTENT OF THE SYSTEM IS LIMITED. PUT ALL OF THAT TOGETHER AND THE BEST CHC IS THAT NO MEASURABLE SNOW MAKES IT EAST OF THE MTNS. THERE IS AROUND A 30 PERCENT CHC FOR A DUSTING FOR THE N TIER OF MD... AND AN EVEN SMALLER 10-20 PERCENT CHC OF A DUSTING SOUTH OF THAT. ONCE THE CLIPPER ROLLS THRU... SKIES CLEAR OUT AGAIN AND NW WINDS KICK UP AGAIN BRINGING COLD TEMPS AROUND 20 FOR MANY BY WED MORNING WITH WIND CHILLS BACK DOWN AROUND ZERO IN THE WESTERN MOUNTAINS AND IN THE TEENS AND SINGLE DIGITS FOR THE REST. IN THE WESTERN UPSLOPE AREAS OF W GRANT W MINERAL AND W ALLEGANY COUNTIES THERE WILL BE A SNOW ADV ISSUED FOR THIS AFTERNOON AND OVERNIGHT. 1 TO 3 INCHES WILL LIKELY PILE UP AGAIN AS SNOW SHOWERS RETURN. AVIATION /09Z-12Z/... VFR CONDITIONS EXPECTED THRU THE TAF PERIOD FOR THE MOST PART. MAY BRIEFLY TOUCH MVFR CONDTIONS WHEN THE CLIPPER ACTUALLY MOVES THRU IN THE AFTERNOON... BUT BETTER CHC THAT IT WILL REMAIN VFR. SW WINDS WILL FLIP TO NW AND BECOME GUSTY AGAIN THIS EVENING AND TONIGHT. SNOW SHOWERS IN THE MOUNTAINS WILL BE REFLECTED IN THE TWEBS. THERE IS A SLIGHT CHC OF A CONVECTIVE BAND OF SNOW SHOWERS DEVELOPING ALONG THE CLIPPER...BUT AGAIN A BETTER CHC THAT SNOW SHOWERS WILL NOT MAKE IT EAST OF THE MOUNTAINS. MARINE... AFTER THE CLIPPER LOW MOVES THRU AND STRENGTHENS A LITTLE BIT WINDS WILL KICK UP ONCE AGAIN AND A SMALL CRAFT ADVISORY IS IN PLACE FOR 9 PM TONIGHT THROUGH 10 AM WEDNESDAY. SMALL CRAFT ADVISORY CONDITIONS THIS WEEKEND IN THE WAKE OF THE LOW PRESSURE SYSTEM AFFECTING THE WATERS THURSDAY NIGHT. LONG TERM /WEDNESDAY THROUGH MONDAY/... BUSY MEDIUM RANGE FORECAST WITH A LOW PRESSURE SYSTEM MAKING ITS WAY FROM THE CENTRAL GULF COAST NORTHEAST ACROSS THE MID ATLANTIC STATES THURSDAY NIGHT. HIGH PRESSURE WILL PUSH THIS SYSTEM OUT TO SEA FOR THE WEEKEND...PROVIDING COOL AND DRY CONDITIONS FOR MOST LOCATIONS THROUGH THE END OF THE FORECAST PERIOD. THE EXCEPTION WILL BE CONTINUED CHANCES FOR UPSLOPE SHOWERS WEST OF THE ALLEGANY FRONT. MAIN FORECAST CHALLENGE IS WITH THE SOUTHERN STREAM LOW APPROACHING THURSDAY. MODELS CONTINUE THEIR INCONSISTENCIES WITH THIS SYSTEM FROM TIMING AND LOCATION TO PRECIPITATION TYPE. WHILE THE TRACK OF THE ACTUAL LOW IS STILL UNCERTAIN...BUT GUIDANCE COMES BACK IN LINE WITH THE LOW PLACED OFF THE NORTHERN MID ATLANTIC COAST FRIDAY MORNING AT 12Z. THE ECMWF IS THE FASTER MODEL WHILE THE NAM IS THE SLOWEST AND THE GFS IN BETWEEN. TOOK A BLEND OF THE THREE USING THE GFS. WHILE EARLIER RUNS BROUGHT PRECIPITATION IN FASTER...GUIDANCE HAS SINCE BACKED OFF. EXPECT PRECIPITATION TO SPREAD NORTHEAST ACROSS THE FORECAST AREA THURSDAY AFTERNOON...WITH HIGHEST POPS MOST LIKELY THURSDAY NIGHT. PRECIPITATION TYPES WITH THIS SYSTEM WILL BE INTERESTING TO WATCH OVER THE NEXT DAY OR TWO. WITH THE VARYING TRACKS OF THE LOW...TYPE FORECASTING HAS BEEN MORE OF A CHALLENGE. USING HPC GUIDANCE AND BUFKIT MODEL SOUNDINGS...A CHANGE OVER FROM SNOW TO FREEZING RAIN IS A POSSIBILITY ACROSS THE CENTRAL FORECAST AREA...AND SWITCHING FROM SNOW TO RAIN IN THE FAR NORTHEAST. HAVE ADDED THE MENTION OF SNOW AND FREEZING RAIN TO THE GRIDS FOR WASHINGTON DC WEST TO THE BLUE RIDGE AND SOUTH THROUGH THE SHENANDOAH VALLEY...WITH A RAIN AND SNOW MIX ACROSS BALTIMORE. CONFIDENCE WITH PRECIPITATION TYPE IS LOW GIVEN VARIANCE OF RECENT MODEL RUNS...SO THIS WILL MOST LIKELY CHANGE OVER THE NEXT 24 TO 48 HOURS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST WEDNESDAY FOR MDZ501. VA...NONE. WV...SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST WEDNESDAY FOR WVZ501-503. MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 10 AM EST WEDNESDAY FOR ANZ530>537. && $$ PREV DISCUSSION...STRONG/SAR UPDATED SHORT TERM/AVIATION/MARINE...HTS md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 651 PM EST WED JAN 31 2007 .AVIATION... MID AND HIGH CLOUDS FORESEEN FOR MOST OF THE NIGHT...WITH THE MID CLOUDS THICKENING/LOWERING WITH TIME AS PER MODEL SOUNDINGS AND MOISTURE TIME SECTIONS. TOWARD DAYBREAK AT KMBS AND EARLY FORENOON AT THE OTHER SITES...EXPECT LOWERING CEILINGS INTO MVFR AS DEARTH OF LOW LEVEL MOISTURE ENDS...WITH THE NORTH AIDED BY TRAJECTORY OFF OF LAKE MICHIGAN. NEARLY ADIABATIC LOW LEVEL LAPSE RATES DEVELOPING THURSDAY AS COLD TEMPERATURES ALOFT PROMOTE EXPECT DIURNAL BOOST FOR SNOW SHOWERS. TAFS ARE INDICATING A PROB30 GROUP BETWEEN 17Z TO 21Z OR 18Z TO 22Z FOR MVFR IN SNOW SHOWERS. NOT ENOUGH CONFIDENCE IN POTENTIAL TONIGHT TO MENTION ANY PRECIPITATION...AS LOW LEVEL MOISTURE WILL BE SPARSE. && .PREV DISCUSSION...ISSUED 434 PM EST WED JAN 31 2007 SHORT TERM...TONIGHT AND THURSDAY OVERNIGHT LOWS LIKELY TO OCCUR SHORTLY AFTER SUNSET...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE AREA WHERE CURRENT TEMPS REMAIN IN THE TEENS...15 AT ADRIAN. THUS...LOWEST OVERNIGHT LOWS ARE EXPECTED IN THAT AREA. THEN TEMPS ARE EXPECTED TO LEVEL OFF AND POSSIBLY CLIMB A LITTLE OVERNIGHT UNDER A WEAK WARM AIR ADVECTION REGIME. THE POTENTIAL FOR SCATTERED LIGHT SNOW SHOWERS ARRIVES AFTER MIDNIGHT AND WILL EXIST THROUGH THURSDAY. LIMITED MOISTURE AND A WEAKENING SYSTEM WILL KEEP SNOW SHOWERS ON THE LIGHT SIDE WITH LITTLE TO NO ACCUMULATION EXPECTED. THE SAGINAW VALLEY STANDS TO SEE THE BEST ACTIVITY AS THAT IS THE FAVORED AREA FOR LAKE LAKE ENHANCED SNOW SHOWERS WITHIN SOUTHWESTERLY FLOW REGIME. LATEST RUC ANALYSIS/SATELLITE DATA SUPPORTS THE MODELS CONSISTENT FORECAST OF THE SHORT WAVE SHEARING OUT WITHIN CONFLUENT FLOW ALOFT OVER THE GREAT LAKES EARLY THURSDAY MORNING. UPPER DIVERGENCE...WITHIN RIGHT ENTRANCE REGION OF DEPARTING JET STREAK... WILL BE SUPPORTIVE OF EXTRA LIFT OVERNIGHT...MAINLY ACROSS THE NORTH HALF OF THE CWA. MODEL SOUNDINGS INDICATE THAT THE VERY DRY 900 TO 700 MB COLUMN OF AIR WILL THEN MOISTEN UP CONSIDERABLY DURING THE EARLY MORNING HOURS. BUT WITH VERY LITTLE INSTABILITY AND LACK OF LOW LEVEL SUPPORT...ANY SNOW SHOWERS SHOULD REMAIN ON THE TAME SIDE. BY THE TIME BETTER LOW LEVEL SUPPORT ARRIVES ON THURSDAY...THE MID AND UPPER LEVEL MOISTURE WILL BEGIN TO STRIP AWAY AS THE UPPER SUPPORT BECOMES SHEARED OUT. HOWEVER WITH INVERSION HEIGHTS AROUND 800 MB ON THURSDAY NORTH OF DETROIT...LINGERING SNOW SHOWERS CANNOT BE RULED OUT. LONG TERM... THE PLAINS WAVE WILL HAVE SHEARED TO OUR EAST BY THURSDAY NIGHT LEAVING ONLY A CHANCE OF LIGHT SNOW SHOWERS OR FLURRIES UNTIL THE NEXT SYSTEM ARRIVES FROM CENTRAL CANADA ON FRIDAY. THIS FEATURE LOOKS TO BE HANDLED WELL JUDGING FROM SATELLITE IMAGERY TODAY BUT IT IS HARD TO GET EXCITED ABOUT THE PROSPECTS FOR SNOW AS IT MOVES THROUGH OUR AREA FRIDAY AFTERNOON. MID LEVEL MOISTURE WILL BE AT A PREMIUM AS THE WAVE WILL BE CUT OFF FROM BOTH GULF AND PACIFIC MOISTURE SOURCES. HOWEVER, A BOOST FROM LAKE MICHIGAN LOOKS REASONABLE AS THE COLD FRONT MOVES THROUGH LOWER MICHIGAN FRIDAY AFTERNOON AND EVENING. THIS IS WORTH CHANCE/SCATTERED POPS FOR SNOW SHOWERS. OUR FIRST SURGE OF ARCTIC AIR WILL ARRIVE BEHIND THIS SYSTEM FRIDAY NIGHT. THE 12Z MODELS ALL SHOW 850 MB TEMPS DROPPING TO AROUND -20C BY SUNRISE SATURDAY MORNING. A SW COMPONENT TO THE WIND WILL INITIALLY HELP WITH SINGLE DIGIT LOW TEMPERATURES, DESPITE SOME CLOUD COVER, AS COLDER SURFACE AIR FLOWS AROUND THE SOUTH END OF LAKE MICHIGAN AND INTO OUR AREA. HOWEVER, THIS SAME SW FLOW WILL STRENGTHEN AND ADVECT SOMEWHAT WARMER AIR INTO THE REGION AS THE SURFACE HIGH DRIFTS EAST AND AHEAD OF THE NEXT WAVE OF LOW PRESSURE SCHEDULED TO ARRIVE ON SATURDAY. IN THIS REGARD, GUIDANCE TEMPERATURES CALLING FOR HIGHS IN THE TEENS LOOK OK BUT THESE READINGS WILL BE ACCOMPANIED BY A 10 TO 20 MPH WIND AND WIND CHILLS NEAR 10 BELOW ZERO. THERE ARE SOME TIMING DIFFERENCES IN THE 12Z MODELS ON THE HANDLING OF THE SATURDAY WAVE. PREFER THE FASTER SOLUTIONS, OF WHICH THE GFS IS ONE, AS RENEWED HEIGHT FALLS GET UNDERWAY IN CENTRAL CANADA AND ANCHOR THE POLAR VORTEX OVER NORTHERN ONTARIO. THIS SYSTEM WILL BRING OUR BEST CHANCE OF SNOW DURING THE WEEKEND AND REPLENISH THE ARCTIC AIR MASS SATURDAY NIGHT AND SUNDAY. THIS WILL BE THE MOST BRUTAL PORTION OF THE COLD OUTBREAK WHEN FACTORING IN BOTH TEMPERATURE AND WIND TAKING WIND CHILL TO AROUND -20F. THE GFS FORECASTS 850 MB TEMPS TO DROP DOWN NEAR -28C WHICH CORRESPONDS TO DAYTIME TEMPERATURES NO BETTER THAN THE SINGLE DIGITS ON SUNDAY. IN FACT, DAYTIME TEMPERATURES TODAY IN REGIONS OF NORTHERN CANADA SHOW A FEW READINGS STILL BELOW ZERO WITH SIMILAR 850 MB TEMPERATURES. IN ADDITION, THERE WILL LIKELY BE CONSIDERABLY MORE OF A SURFACE PRESSURE TROUGH IN THE LEE OF LAKE MICHIGAN WHICH WILL DIRECT A SW FLOW OF LESS MODIFIED AIR INTO SE MICHIGAN. THE LAST TIME METRO DETROIT HAD AT LEAST TWO CONSECUTIVE DAYS OF SINGLE DIGIT HIGH TEMPERATURES WAS IN JANUARY 1994. VERY LITTLE TEMPERATURE MODERATION IS EXPECTED ON MONDAY AS THE CORE OF THE POLAR VORTEX MOVES OVER THE GREAT LAKES. THE GLOBAL MODELS DO SHOW THE VORTEX MOVING EAST BY TUESDAY BUT DEEP NW FLOW WILL CONTINUE THE SUPPLY OF ARCTIC AIR THROUGH THE MIDDLE OF NEXT WEEK. SOME MODERATION IS POSSIBLE ON TUESDAY AND WEDNESDAY AS THE WIND BACKS TOWARD THE WEST AND NORTHWEST, PREVENTING THE LESS MODIFIED AIR FROM MOVING INTO THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 3 PM THURSDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422... UNTIL 10 AM THURSDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY FOR WINDS...UNTIL 10 AM THURSDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FOR WINDS... && $$ AVIATION...DWD SHORT TERM...JDS LONG TERM....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 434 PM EST WED JAN 31 2007 .SHORT TERM...TONIGHT AND THURSDAY OVERNIGHT LOWS LIKELY TO OCCUR SHORTLY AFTER SUNSET...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE AREA WHERE CURRENT TEMPS REMAIN IN THE TEENS...15 AT ADRIAN. THUS...LOWEST OVERNIGHT LOWS ARE EXPECTED IN THAT AREA. THEN TEMPS ARE EXPECTED TO LEVEL OFF AND POSSIBLY CLIMB A LITTLE OVERNIGHT UNDER A WEAK WARM AIR ADVECTION REGIME. THE POTENTIAL FOR SCATTERED LIGHT SNOW SHOWERS ARRIVES AFTER MIDNIGHT AND WILL EXIST THROUGH THURSDAY. LIMITED MOISTURE AND A WEAKENING SYSTEM WILL KEEP SNOW SHOWERS ON THE LIGHT SIDE WITH LITTLE TO NO ACCUMULATION EXPECTED. THE SAGINAW VALLEY STANDS TO SEE THE BEST ACTIVITY AS THAT IS THE FAVORED AREA FOR LAKE LAKE ENHANCED SNOW SHOWERS WITHIN SOUTHWESTERLY FLOW REGIME. LATEST RUC ANALYSIS/SATELLITE DATA SUPPORTS THE MODELS CONSISTENT FORECAST OF THE SHORT WAVE SHEARING OUT WITHIN CONFLUENT FLOW ALOFT OVER THE GREAT LAKES EARLY THURSDAY MORNING. UPPER DIVERGENCE...WITHIN RIGHT ENTRANCE REGION OF DEPARTING JET STREAK... WILL BE SUPPORTIVE OF EXTRA LIFT OVERNIGHT...MAINLY ACROSS THE NORTH HALF OF THE CWA. MODEL SOUNDINGS INDICATE THAT THE VERY DRY 900 TO 700 MB COLUMN OF AIR WILL THEN MOISTEN UP CONSIDERABLY DURING THE EARLY MORNING HOURS. BUT WITH VERY LITTLE INSTABILITY AND LACK OF LOW LEVEL SUPPORT...ANY SNOW SHOWERS SHOULD REMAIN ON THE TAME SIDE. BY THE TIME BETTER LOW LEVEL SUPPORT ARRIVES ON THURSDAY...THE MID AND UPPER LEVEL MOISTURE WILL BEGIN TO STRIP AWAY AS THE UPPER SUPPORT BECOMES SHEARED OUT. HOWEVER WITH INVERSION HEIGHTS AROUND 800 MB ON THURSDAY NORTH OF DETROIT...LINGERING SNOW SHOWERS CANNOT BE RULED OUT. && .LONG TERM...THE PLAINS WAVE WILL HAVE SHEARED TO OUR EAST BY THURSDAY NIGHT LEAVING ONLY A CHANCE OF LIGHT SNOW SHOWERS OR FLURRIES UNTIL THE NEXT SYSTEM ARRIVES FROM CENTRAL CANADA ON FRIDAY. THIS FEATURE LOOKS TO BE HANDLED WELL JUDGING FROM SATELLITE IMAGERY TODAY BUT IT IS HARD TO GET EXCITED ABOUT THE PROSPECTS FOR SNOW AS IT MOVES THROUGH OUR AREA FRIDAY AFTERNOON. MID LEVEL MOISTURE WILL BE AT A PREMIUM AS THE WAVE WILL BE CUT OFF FROM BOTH GULF AND PACIFIC MOISTURE SOURCES. HOWEVER, A BOOST FROM LAKE MICHIGAN LOOKS REASONABLE AS THE COLD FRONT MOVES THROUGH LOWER MICHIGAN FRIDAY AFTERNOON AND EVENING. THIS IS WORTH CHANCE/SCATTERED POPS FOR SNOW SHOWERS. OUR FIRST SURGE OF ARCTIC AIR WILL ARRIVE BEHIND THIS SYSTEM FRIDAY NIGHT. THE 12Z MODELS ALL SHOW 850 MB TEMPS DROPPING TO AROUND -20C BY SUNRISE SATURDAY MORNING. A SW COMPONENT TO THE WIND WILL INITIALLY HELP WITH SINGLE DIGIT LOW TEMPERATURES, DESPITE SOME CLOUD COVER, AS COLDER SURFACE AIR FLOWS AROUND THE SOUTH END OF LAKE MICHIGAN AND INTO OUR AREA. HOWEVER, THIS SAME SW FLOW WILL STRENGTHEN AND ADVECT SOMEWHAT WARMER AIR INTO THE REGION AS THE SURFACE HIGH DRIFTS EAST AND AHEAD OF THE NEXT WAVE OF LOW PRESSURE SCHEDULED TO ARRIVE ON SATURDAY. IN THIS REGARD, GUIDANCE TEMPERATURES CALLING FOR HIGHS IN THE TEENS LOOK OK BUT THESE READINGS WILL BE ACCOMPANIED BY A 10 TO 20 MPH WIND AND WIND CHILLS NEAR 10 BELOW ZERO. THERE ARE SOME TIMING DIFFERENCES IN THE 12Z MODELS ON THE HANDLING OF THE SATURDAY WAVE. PREFER THE FASTER SOLUTIONS, OF WHICH THE GFS IS ONE, AS RENEWED HEIGHT FALLS GET UNDERWAY IN CENTRAL CANADA AND ANCHOR THE POLAR VORTEX OVER NORTHERN ONTARIO. THIS SYSTEM WILL BRING OUR BEST CHANCE OF SNOW DURING THE WEEKEND AND REPLENISH THE ARCTIC AIR MASS SATURDAY NIGHT AND SUNDAY. THIS WILL BE THE MOST BRUTAL PORTION OF THE COLD OUTBREAK WHEN FACTORING IN BOTH TEMPERATURE AND WIND TAKING WIND CHILL TO AROUND -20F. THE GFS FORECASTS 850 MB TEMPS TO DROP DOWN NEAR -28C WHICH CORRESPONDS TO DAYTIME TEMPERATURES NO BETTER THAN THE SINGLE DIGITS ON SUNDAY. IN FACT, DAYTIME TEMPERATURES TODAY IN REGIONS OF NORTHERN CANADA SHOW A FEW READINGS STILL BELOW ZERO WITH SIMILAR 850 MB TEMPERATURES. IN ADDITION, THERE WILL LIKELY BE CONSIDERABLY MORE OF A SURFACE PRESSURE TROUGH IN THE LEE OF LAKE MICHIGAN WHICH WILL DIRECT A SW FLOW OF LESS MODIFIED AIR INTO SE MICHIGAN. THE LAST TIME METRO DETROIT HAD AT LEAST TWO CONSECUTIVE DAYS OF SINGLE DIGIT HIGH TEMPERATURES WAS IN JANUARY 1994. VERY LITTLE TEMPERATURE MODERATION IS EXPECTED ON MONDAY AS THE CORE OF THE POLAR VORTEX MOVES OVER THE GREAT LAKES. THE GLOBAL MODELS DO SHOW THE VORTEX MOVING EAST BY TUESDAY BUT DEEP NW FLOW WILL CONTINUE THE SUPPLY OF ARCTIC AIR THROUGH THE MIDDLE OF NEXT WEEK. SOME MODERATION IS POSSIBLE ON TUESDAY AND WEDNESDAY AS THE WIND BACKS TOWARD THE WEST AND NORTHWEST, PREVENTING THE LESS MODIFIED AIR FROM MOVING INTO THE REGION. && .AVIATION...ISSUED AT 104 PM EST SOUTHWEST FLOW AND WEAK WARM AIR ADVECTION WILL CONTINUE TO SUPPORT MID CLOUDS TODAY. MARINE CLOUDS TO CONTINUE THIS AFTERNOON AT THE FNT AND MBS TERMINALS...WITH MVFR CEILINGS EXPECTED PERIODICALLY. MVFR CEILINGS TO MOVE IN AGAIN AND BECOME MORE WIDESPREAD AFTER MIDNIGHT...IN ASSOCIATION WITH THE APPROACH OF A WEAK CLIPPER SYSTEM. MVFR CEILINGS ARE THEN EXPECTED TO REMAIN IN PLACE THROUGH THIS TAF PERIOD. THERE WILL BE SCATTERED LIGHT SNOW SHOWERS AROUND ON THURSDAY. SOUTHWESTERLY FLOW TO PROVIDE FNT AND MBS WITH AN OPPORTUNITY FOR SOME LAKE ENHANCED SNOW SHOWERS...THUS THE REASONING FOR A PERIOD OF MVFR VISIBILITIES IN THAT AREA. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN THURSDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422 UNTIL 10 AM THURSDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY FOR WINDS...LCZ460 UNTIL 10 AM THURSDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FOR WINDS...UNTIL 10 AM THURSDAY. && $$ SHORT TERM...JDS LONG TERM....BT AVIATION...JDS YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 330 PM EST WED JAN 31 2007 ...SEVERAL DAYS OF VERY COLD AIR EXPECTED THIS WEEKEND INTO NEXT WEEK... .SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED OVERALL UPPER TROUGHING COVERING MUCH OF NORTH AMERICA...EXCEPT ALONG THE WEST COAST INTO ALASKA WHERE A VERY AMPLIFIED RIDGE EXISTS. FAIRBANKS 850MB TEMP WAS 10C! WITHIN THE UPPER TROUGH...THERE ARE A FEW FEATURES OF INTEREST. THE FIRST IS A SHRTWV TROUGH OVER WESTERN MINNESOTA. DPVA/ISENTROPIC LIFT AHEAD OF THE TROUGH AND A LITTLE MORE MOISTURE HAS ALLOWED FOR THE DEVELOPMENT OF AN AREA OF LIGHT SNOW ON THE MINNEAPOLIS RADAR ACROSS THE MINNEAPOLIS AREA INTO SW WISCONSIN. HOWEVER...THE NORTH END OF THIS REFLECTIVITY SHIELD IS MAINLY VIRGA...DUE TO DRY LOW LEVEL AIR AS NOTED BY THE 12Z MPX SOUNDING AND SURFACE DEWPOINT DEPRESSIONS OF 10-20F. THIS DRY LOW LEVEL AIR...COMBINED WITH A SOUTHERLY FLOW AHEAD OF A 1007MB LOW WEST OF DULUTH...HAS HELPED PUSH THE LAKE EFFECT CONVERGENT BAND AFFECTING THE KEWEENAW BACK OUT OVER THE NORTH CENTRAL PART OF LAKE SUPERIOR. THE RESULT IS NOW ONLY A FEW MID/HIGH CLOUDS ACROSS THE CWA. AS FAR AS AMOUNTS GO REGARDING THE EXPIRED HEADLINES... PLACES ACROSS THE KEWEENAW ENDING UP WITH 4 TO 6 INCHES WHILE THOSE BETWEEN THE PICTURED ROCKS NATIONAL LAKESHORE AND TAHQUAMENON FALLS ENDED UP WITH 4 TO 7 INCHES. ACROSS THE LUCE COUNTY LINE IN PARADISE...HOWEVER...SPOTTERS HAVE REPORTED 10 TO 15 INCHES. THE SECOND FEATURE OF INTEREST...WHICH IS EXPECTED TO BRING THE COLD AIR ALONG WITH A PERIOD OF HEAVY LES TO WESTERN UPPER MICHIGAN...IS A STRONGER SHRTWV LOCATED OVER NORTHERN SASKATCHEWAN. BEHIND THIS SHRTWV...850MB TEMPS ON 12Z RAOBS WERE OBSERVED NEAR -30C. THE ACTUAL ARCTIC FRONTAL BOUNDARY CAN BE SEEN DROPPING THROUGH CENTRAL SASKATCHEWAN/MANITOBA...WITH FALLING TEMPERATURES BEHIND IT. && .SHORT TERM (TONIGHT AND THU)... TONIGHT...THE SHRTWV TROUGH OVER MINNESOTA IS PROGGED TO TRACK ACROSS MUCH OF UPPER MICHIGAN BY 06Z. ALL MODELS SEEM TO HAVE A GOOD HANDLE ON THE SNOW AFFECTING THE MINNEAPOLIS AREA AND BASICALLY HAVE MUCH OF IT GOING ACROSS WISCONSIN INTO LOWER MICHIGAN. IT APPEARS THE NORTHERN END MAY CLIP THE SOUTH CENTRAL COUNTIES...BUT AGAIN GIVEN THE LOW LEVEL DRY AIR SEEN ACROSS THE CWA AND ON THE 12Z GRB SOUNDING...DO NOT BELIEVE MUCH SNOWFALL WILL OCCUR. MEANWHILE...HIGH RESOLUTION MODELS DEPICT THAT THE SURFACE LOW ASSOCIATED WITH THE SHRTWV WILL REDEVELOP OVER CENTRAL LAKE SUPERIOR THIS EVENING...THEN MOVE TO EASTERN LAKE SUPERIOR AFTER MIDNIGHT. THE TROUGH EXTENDING SW FROM THE LOW WILL LIKELY CONTAIN SOME LES ALONG IT...PERHAPS EVEN THE CURRENT LES BAND THAT EXISTS ON THE WESTERN PORTION OF LAKE SUPERIOR. HOWEVER...MODELS DEPICT THE CONVERGENCE TO NOT BE AS STRONG AS EXPERIENCED LAST NIGHT ALONG THIS TROUGH...AND THUS THE QPF AMOUNTS ARE NOT NEARLY AS GREAT. HAVE SLOWED DOWN THE MOVEMENT OF THE LES INTO THE KEWEENAW BASED ON THE 13 KM RUC AND OUR HIGH RESOLUTION WRF RUN SINCE LOW LEVEL WINDS ARE PROGGED TO STAY SW UNTIL AFTER 06Z. THEREFORE SNOW AMOUNTS HAVE BEEN CUT BACK TONIGHT. THU...AS THE SHRTWV OVER NORTHERN SASKATCHEWAN PLOWS SOUTHWARD INTO THE NORTHERN PLAINS...RESULTING IN THE DEVELOPMENT OF A SURFACE LOW WHICH TRACKS TO DULUTH BY 00Z...SW FLOW REDEVELOPS AT THE SURFACE. HOWEVER...THE PRESSURE GRADIENT AHEAD OF THIS LOW IS NOT ALL THAT STRONG...WHICH MEANS THAT THE TROUGH THAT MOVES INTO THE KEWEENAW PENINSULA TONIGHT MAY GET HUNG UP OVER KEWEENAW COUNTY ON THU. THIS SCENARIO IS DEPICTED WELL IN HIGH RESOLUTION RUNS AND THE GFS. THEREFORE HAVE RAISED BOTH POPS AND SNOW AMOUNTS FOR THE KEWEENAW. KEPT AMOUNTS JUST BELOW ADVISORY CRITERIA...THOUGH...SINCE THE CONVERGENCE DOES NOT LOOK PARTICULARLY STRONG WITH ONLY A 90 DEGREE CHANGE IN DIRECTION ALONG THE BOUNDARY (COMPARED TO 180 DEGREES WITH THIS PAST EVENT). ELSEWHERE...DRY AIR FOLLOWING THE PASSAGE OF TONIGHTS SHRTWV LOOKS TO STAY IN PLACE...WHICH WILL HELP KEEP THE CWA DRY. ONLY MADE A FEW TWEAKS TO GOING FORECAST TEMPERATURES FOR TONIGHT AND THU BASED ON INCREASES/DECREASES IN CLOUD COVER AFFECTING RADIATION PROCESSES. NOTE THAT THESE READINGS WILL BE THE WARMEST THAT WEST AND CENTRAL UPPER MICHIGAN WILL SEE FOR AWHILE...PROBABLY THROUGH MUCH OF NEXT WEEK. .LONG TERM (THU NIGHT THROUGH NEXT WED)... FCST FOCUS FOR THU NGT/FRI CONCERNS TIMING/IMPACT OF FAIRLY SHARP SHRTWV FCST TO DROP FM SCNTRL CAN INTO THE UPR GRT LKS. MODEL TREND HAS BEEN TO SPEED UP THIS FEATURE AND ASSOCIATED SFC LO/ARCTIC FNT...SO FOLLOWED THE FASTER GFS/UKMET/CNDN MODELS FOR TIMING THE ARCTIC BNDRY PER NCEP PREFERENCE OVER THE SLOWER NAM. GFS SHOWS HEALTHY DPVA/H85-5 QVECTOR CNVGC/UPR DVGC/12HR H5 HGT FALLS NEAR 150M ASSOCIATED WITH SHRTWV MOVING INTO WI AT 12Z FRI AND THEN TO LK HURON BY 00Z SAT. ARCTIC FNT PROGGED TO REACH THE WRN ZNS BY 12Z FRI BEFORE PASSING ERY SHORTLY AFT 18Z. CONSIDERING THESE POTENT DYNAMICS AND DEEP MSTR DEPICTED ON THE GFS FCST SDNGS...WL MAINTAIN CATEGORICAL POPS AOA MOS FCST OVER THE W AS EARLY AS LATE THU NGT AND THEN ACRS ALL BUT THE SCNTRL ON FRI. SINCE THE SHRTWV IS PROGGED TO MOVE QUICKER WITH EARLIER ARRIVAL OF DPVA THU NGT AND THEN DNVA/H85-5 QVECTOR DVGC/LARGER SCALE SUBSIDENCE ON FRI...THE ONLY ADJUSTMENTS TO GOING FCST WX WL BE TO START THE HIER POPS EARLIER W-E THU NGT AND THEN END SYNOPTIC SN POPS EARLIER FRI AFTN. ARRIVAL OF ARCTIC AIR WL SPUR ONSET OF LES OFF LK SUP ON FRI...AND THERE APPEARS TO BE AT LEAST A 6-HR PD OF LK ENHANCEMENT OVER THE W BEFORE THE DYNAMICS EXIT FRI AFTN AND THE ACTIVITY EVOLVES TO PURE LES. SINCE FINER SCALE EXTENDED RUC13 GUIDANCE HINTS THE SFC LO MAY GET STUCK OVER ERN LK SUP WITH LATENT HEATING OFF THE WARM LK SUP WATERS...THINK THE MORE W LLVL WIND FIELD WL BE LESS FVRBL FOR LK ENHANCEMENT E OF THE HURON MTNS. ALTHOUGH THE ARRIVAL OF THE VERY LO H85 TEMPS (DOWN TO -25C AT IWD BY 00Z SAT) WL NEGATIVELY IMPACT SN GROWTH MICROPHYSICS...HAVE OPTED TO ISSUE WINTER STORM WATCH FOR LATE THU NGT THRU FRI FOR WRN COUNTIES BORDERING LK SUP AS WELL AS BARAGA COUNTY. WL GO WITH FALLING TEMPS OVER THE W ON FRI WITH ARRIVAL OF COLDER AIR. 12Z UKMET/GFS/ECMWF SHOW REINFORCING SHRTWV/DPVA/H85-5 QVECTOR CNVGC ARRIVING FRI NGT BEFORE DEPARTING ON SAT. ARRIVAL OF THIS SHRTWV/ DYNAMICS/DEEPER MSTR WL MAINTAIN HIER POPS FOR LK ENHANCED SN...BUT AIR IS SO COLD (H85 TEMPS FCST IN THE -24C TO -28C RANGE) LES OVERALL WL BE RELATIVELY LGT WITH POOR DENDRITIC SN GROWTH MICROPHYSICS. ONLY CONCERN WL BE BAND OF HEAVIER SHSN THAT COULD DVLP IN SHARP CNVGC BTWN MORE WLY LAND BREEZE FLOW OVER LAND AND SYNOPTIC SCALE NW WIND OVER LK SUP. LATER SHIFTS WL NEED TO EVALUATE THE NEED FOR ANY HEADLINES ONCE THE LOCATION OF THESE LLVL CNVGC AREAS CAN BE DETERMINED WITH MORE CONFIDENCE. WITH MORE WLY LAND BREEZE FLOW FRI NGT IN BACKED WINDS AHEAD OF APRCHG SHRTWV...PREFER LO END OF MOS GUIDANCE FOR LO TEMPS. GOING FCST HI TEMPS BLO ZERO OVER THE INTERIOR W SEEM RSNBL ON SAT GIVEN GFS/ECMWF FCST OF H85 TEMPS APRCHG -30C BY 00Z SUN IN WAKE OF SHRTWV. 00Z-12Z OPS MODELS/00Z GFS REFCST ENSEMBLE MEAN IN GOOD AGREEMENT SHOWING HI AMPLITUDE TROF IN ERN NAMERICA PERSISTING THIS WEEKEND INTO EARLY NEXT WEEK. GFS/ECMWF BOTH FCST H85 TEMP BOTTOMING OUT AS LO AS -28C TO -32C THIS WEEKEND BEFORE MODERATING MON-WED. 12Z TRENDS ARE SIMILAR...BUT LESS AGGRESSIVE AT RAISING THE H85 TEMPS THAN EARLIER RUNS. HOWEVER...GFS REFCST ENSEMBLE GUIDANCE HINT THAT CORE OF COLDEST AIR (H85 TEMPS AOA 2 STANDARD DEVIATIONS BLO NORMAL) WL NOT ARRIVE UNTIL MON/TUE FOLLOWING REINFORCING SHRTWV/SFC LO ON SUN/MON AS FCST BY 06Z GFS. THIS FCST WOULD SUG SGNFT MODERATION WL NOT ARRIVE UNTIL WED. WL GO WITH FCST TEMPS NR THE LO END OF MOS GUIDANCE FOR SAT-TUE. FCST SOMEWHAT HIER...MORE WDSPRD POPS ON SUN/SUN NGT TO ACCOUNT FOR PSBL REINFORCING SHRTWV. THE OPS MODELS DO SHOW A SOMEWHAT SHARPER PRES GRADIENT ON MON IN THE WAKE OF THIS SHRTWV AND IN ADVANCE OF ARCTIC HI PRES BLDG INTO THE NRN PLAINS...WHICH ALG WITH SAT (SHARPER PRES GRADIENT IN THE WAKE OF FRI LO) MIGHT END UP BEING THE DAYS WITH THE LOWEST WIND CHILLS AT LEAST CLOSE TO WRNG CRITERIA. OTRW...THE ONLY PCPN THRU THE PD WL BE LES MAINLY IN THE NW WIND SN BELTS LIMITED BY VERY COLD AIR THAT WL HAVE A NEGATIVE IMPACT ON SN GROWTH. BUT... SMALL SNFLAKE SIZE WL BE EFFECTIVE AT LIMITING VSBY. COORDINATED WITH DLH/GRB. && .MQT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH THU NIGHT AND FRI MIZ001>004-009-084. && $$ AJ (SHORT TERM) KC (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1056 AM EST WED JAN 31 2007 ...SEVERAL DAYS OF VERY COLD AIR EXPECTED THIS WEEKEND INTO EARLY NEXT WEEK... .SYNOPSIS... 15Z WATER VAPOR LOOP AND 12Z RAOBS SHOW WEAK RIDGING OCCURRING OVER UPPER MICHIGAN AHEAD OF A SHRTWV TROUGH WHICH EXTENDS FROM NW MINNESOTA INTO SE WYOMING. WARM ADVECTION MID AND HIGH CLOUDS CONTINUE TO BE GENERATED AHEAD OF THIS SHRTWV TROUGH...THOUGH VERY DRY AIR BETWEEN 650-900MB AS SEEN ON THE 12Z MPX...GRB AND INL SOUNDINGS HAVE KEPT SNOWFALL PRODUCTION AT A MINIMUM. IN FACT...THE ONLY SNOW OCCURRING IS BACK IN THE FARGO AREA...WHICH HAPPENS TO BE ON THE BACK SIDE OF A 1010MB LOW IN NW MINNESOTA. A TROUGH EXISTS TO THE E OF THE LOW...ACROSS CENTRAL LAKE SUPERIOR AND SE TO WHITEFISH BAY. KMQT RADAR LOOP CONTINUES TO SHOW SOME DECENT BANDS ALONG THIS TROUGH NEAR GRAND MARAIS EASTWARD ACROSS NORTHERN LUCE COUNTY. THE HOUGHTON COUNTY AIRPORT IS ALSO ON THE SOUTHERN EDGE OF THE BAND AS NOTED BY VISIBILITIES OF 1SM OR LESS FOR THE PAST 5 HOURS. HAVE MADE NUMEROUS CALLS TO COOP OBSERVERS THIS MORNING FOR VERIFICATION OF THE WARNINGS/ADVISORIES AND FOUND THAT SNOWFALL RATES WERE AS EXPECTED...BETWEEN 1 AND 2 INCHES AN HOUR. HOWEVER...GIVEN THAT THE CONVERGENT BANDS (WHICH LOOK DECENT ON VISIBLE SATELLITE IMAGERY RIGHT NOW) NEVER STAYED IN ONE PLACE FOR MORE THAN 4 HOURS...MOST OF THE AMOUNTS HAVE BEEN UNDER 6 INCHES IN THE PAST 12 HOURS. THE COMBINATION OF LAND BREEZES AND HEIGHT RISES AHEAD OF THE SHRTWV TROUGH HAVE HELPED TO PUSH THE TROUGH AND HEAVIER LES NORTHWARD... AND THIS TREND CAN BE OBSERVED IN THE LATEST RADAR LOOP. LASTLY... TO OUR N...THE POLAR VORTEX STILL SITS UP IN HUDSON BAY...THOUGH IS EXPECTED TO DROP S THIS WEEKEND TO BRING THE UPCOMING COLD WAVE. && .UPDATE... MAIN UPDATE CONCERN IS ONGOING HEADLINES. THE 12Z RUC SEEMED TO HAVE THE BEST HANDLE ON THE CURRENT PRESSURE FIELD AND CONVERGENT AREAS FOR THE PAST FEW HOURS...THUS HAVE FOLLOWED IT FOR THE UPDATE. THE SURFACE TROUGH IS PROGGED TO CONTINUE LIFTING NORTHWARD...WITH PERHAPS THE DEVELOPMENT OF A SURFACE LOW/MESO-LOW OVER CENTRAL LAKE SUPERIOR BY 00Z. THIS SHOULD HELP PULL MOST...IF NOT ALL THE LAKE EFFECT...OUT OF UPPER MICHIGAN. STILL KEPT SOME ISOLATED SNOW SHOWERS OVER KEWEENAW COUNTY AFTER 20Z IN THE EVENT THAT THE BAND IS SLOWER TO MOVE NORTH. AS FAR AS HEADLINES GO...WILL LET THEM EXPIRE ON SCHEDULE SINCE THERE STILL IS SOME DECENT SNOWFALL RATES OCCURRING WITH THE LAKE EFFECT BANDS. SNOW AMOUNTS AND QPF FORECAST LOOK ON TRACK. OUTSIDE OF THE LAKE EFFECT...MID AND HIGH CLOUDS ARE EXPECTED TO CONTINUE SPREADING ACROSS THE CWA SINCE WE REMAIN DOWNSTREAM OF THE NW MINNESOTA SHRTWV TROUGH. THESE CLOUDS WILL KEEP SOLAR INSOLATION LOW...HOWEVER A 5 TO 15 MPH SW WIND SHOULD ALLOW TEMPERATURES TO CLIMB TO GOING FORECAST HIGHS. NO CHANGES MADE TO TEMPS OR SKY COVER. GRID UPDATE...ARBWSWMQT AND ARBZFPMQT UPDATES ALREADY ISSUED. && .PREV DISCUSSION... MAIN FCST ISSUES REVOLVE AROUND ONGOING HEADLINE LES EVENT...ANOTHER POSSIBLE SIGNIFICANT LAKE EFFECT/LAKE ENHANCED EVENT FRI WITH SHORTWAVE PASSAGE...AND THEN THE VERY COLD AIR TO SETTLE OVER THE AREA IN ITS WAKE. WATER VAPOR IMAGERY AND GFS ANALYSIS SHOW A VERY PRONOUNCED RIDGE ALONG THE W COAST OF NAMERICA. 500MB HEIGHTS THERE ARE 2.5 STANDARD DEVIATIONS ABOVE NORMAL WHICH TRANSLATES TO 370M ABOVE NORMAL IN THE CORE OF THE ANOMALY OVER SE ALASKA/SRN YUKON. DOWNSTREAM TROF IS DOMINATING THE ERN 2/3RDS OF NAMERICA...AND THE TROF WILL ONLY BECOME DEEPER DUE TO THE UPSTREAM POSTIVE HEIGHT ANOMALY. IN THE NW FLOW...ONE SHORTWAVE WAS DROPPING SE THRU THE DAKOTAS WHILE ANOTHER WAS TRACKING SE JUST TO THE E OF LAKE SUPERIOR. THE LATTER SHORTWAVE HAS HELPED INTENSIFY LES OVER ERN LAKE SUPERIOR WHICH IS OCCURRING IN A CONVERGENCE ZONE BTWN WRLY WINDS OVER UPPER MI AND NW WINDS OVER THE LAKE. LES BANDS HAVE HAD A FAIR AMOUNT OF SEPARATION WHICH WILL LIMIT THE AREAL COVERAGE OF HIGHER ACCUMULATIONS. MOST INTENSE BANDS ARE WIDELY SEPARATED. SFC WIND FIELDS SHOW CONVERGENCE ZONE EXTENDING W ACROSS THE KEWEENAW (WIND DIRECTION WAS SSW AT ONTONAGON AND NW AT HOUGHTON). WOULD EXPECT SOME HEAVIER SNOW TO BE OCCURRING IN THE PAINESDALE VCNTY. EVEN SO...DRIER UPSTREAM AIRMASS PER 00Z KINL SOUNDING IS PROBABLY HAVING A NEGATIVE IMPACT ON SNOW INTENSITY OVER THE NW FCST AREA. WITH PASSAGE OF SHORTWAVE JUST E OF LAKE SUPERIOR...WINDS WILL VEER A BIT MORE ACROSS ERN LAKE SUPERIOR OVER THE NEXT FEW HRS...AND SPEEDS WILL DECREASE. THE VEERING WINDS OVER THE LAKE WILL CONTINUE TO FOCUS CONVERGENCE ACROSS ERN ALGER/NRN LUCE COUNTIES EARLY THIS MORNING WHILE CONVERGENCE ZONE TO THE NW WILL REMAIN NEARLY STATIONARY ACROSS CNTRL HOUGHTON COUNTY. FROM MID MORNING INTO THE AFTN...WINDS WILL BACK SW IN RESPONSE TO APPROACH OF THE NRN EXTENSION OF SHORTWAVE CURRENTLY OVER THE DAKOTAS. MODELS ARE ACTUALLY IN DECENT AGREEMENT ON THE WIND FIELD RESPONSE. IT APPEARS WINDS WILL BE SUFFICIENTLY BACKED TO END LES OVER ALGER/LUCE AROUND 18Z. SO...WILL ALLOW ONGOING WARNING FOR THAT AREA TO CONTINUE AS IS UNTIL EXPIRATION AT 18Z. WIDE SEPARATION BTWN STRONGEST LES BANDS WILL PROBABLY RESULT IN ONLY A FEW LOCATIONS REACHING THE WARNING CRITERIA OF 10 INCHES FOR THIS EVENT. MEANWHILE...THERE IS A BIT MORE UNCERTAINTY ON WIND FIELDS OVER/NEAR THE KEWEENAW DUE TO SMALL BUT IMPORTANT DIFFERENCES IN TIMING THE NWD MOVEMENT OF CONVERGENCE ZONE. HOWEVER...IT DOES APPEAR THAT BY LATE AFTN...MAIN CONVERGENCE WILL HAVE SHIFTED JUST N AND NW OF THE KEWEENAW. WITH WIND FIELDS DIMINISHING SUBSTANTIALLY THRU THE DAY AND THUS WEAKENING THE CONVERGENCE...WOULD EXPECT LES IN THE MAIN BAND TO DIMINISH AS IT LIFTS N ACROSS THE KEWEENAW. OF COURSE...THAT IS NOT ALWAYS THE CASE. IT LOOKS LIKE MUCH OF ONTONAGON/SRN HOUGHTON COUNTIES HAVE SEEN VERY LITTLE/NO SNOW. RECENT REPORT FROM MASS CITY WAS JUST LIGHT SNOW. PERHAPS THE AREA JUST N OF M-38 HAS SEEN SOME ACCUMULATION...BUT THERE IS NO WAY TO KNOW AT THIS TIME OF DAY. BASED ON THE SOLID SSW WIND AT ONTONAGON AND REPORT FROM MASS CITY...WILL DROP WARNING FOR ONTONAGON COUNTY AS CONVERGENCE AREA IS PROBABLY JUST N OF COUNTY. WILL THUS ALSO DROP SRN HOUGHTON COUNTY ADVY. NOT SURE WARNING WILL VERIFY FOR NRN HOUGHTON COUNTY...BUT WITH CONVERGENCE ZONE THERE...WILL LET IT RIDE. IT`S POSSIBLE THAT HEADLINE FOR KEWEENAW COUNTY MAY NEED TO BE EXTENDED BEYOND 18Z...BUT IT SEEMS REASONABLE AT THIS POINT TO SEE HOW THE WIND FIELDS ACTUALLY EVOVLE DURING THE MID/LATE MORNING BEFORE MAKING ANY NECESSARY HEADLINE ADJUSTMENTS. AWAY FROM LES...EXPECT DRY WEATHER TODAY. PASSAGE OF SHORTWAVE TONIGHT WILL RESULT IN WINDS VEERING MORE WRLY AGAIN OVER WRN LAKE SUPERIOR. IF A BAND OF HEAVIER LES REMAINS INTO THE EVENING OVER THE LAKE IN THE CONVERGENT ZONE THAT LIFTED N TODAY...IT WILL MOVE BACK ONSHORE OVER THE KEWEENAW. WHILE GFS FCST SOUNDING FOR KCMX INDICATES MIDLEVEL DRYING AND INVERSION SETTLING DOWN TO 4-5KFT...NAM LOOKS MORE PROMISING FOR HEAVIER SNOW WITH INVERSION AT 6-7KFT AND DEEP LAYER OF FAVORABLE DENDRITIC SNOW CRYSTAL GROWTH TEMPS. FOW NOW...WILL PAINT NEAR ADVY LEVEL SNOW ACCUMULATIONS ACROSS THE KEWEENAW. TROF HANGS UP OVER ERN LAKE SUPERIOR SO WSW WINDS WILL KEEP LES OFFSHORE OF THE ERN FCST AREA. WINDS BACK TOWARD THE SW OVER NRN LAKE MICHIGAN...BUT ALL THE MODELS SUGGEST WINDS WILL HAVE JUST ENOUGH WRLY COMPONENT TO KEEP LES E OF FCST AREA. OTHERWISE...MIGHT SEEM PATCHY -SN/FLURRIES WITH PASSAGE OF SHORTWAVE. EXPECT A RELATIVELY QUIET DAY THU UNDER WEAK SHORTWAVE RIDGING DOWNSTREAM OF SHORTWAVE TROF DROPPING INTO THE NRN PLAINS. THIS WILL BE THE SYSTEM INITIATING THE ARCTIC BLAST FOR THE END OF THE WEEK. WINDS WILL MAINTAIN ENOUGH OF WRLY COMPONENT THU OVER WRN LAKE SUPERIOR TO KEEP LES IN THE PICTURE FOR THE KEWEENAW. HOWEVER... DRYING EVIDENT IN GFS/NAM FCST SOUNDINGS AND INVERSION DROPPING TO 3-4KFT WILL KEEP LES ON THE LIGHT SIDE...PERHAPS NOT MUCH MORE THAN FLURRIES BY AFTN. SHORTWAVE WILL SWING THRU THE WRN GREAT LAKES FRI WITH SFC LOW PRES ORGANIZING AND THEN DEEPENING MOST LIKELY OVER ERN LAKE SUPERIOR DUE TO HEAT/MOISTURE FLUXES (850MB TEMPS WILL BE AROUND -16C FRI MORNING). GIVEN THE INSTABILITY OVER THE LAKE AND DEEP LAYER FORCING WITH SHORTWAVE STRENGTHENING WITH TIME PER NAM/GFS 850-500MB QVECTOR CONVERGENCE...SFC LOW AND THE WIND FIELDS TO THE W AND N OF SFC LOW WILL PROBABLY BE STRONGER THAN WHAT ANY OF THE 00Z MODELS SHOW. SHOULD BE A GOOD SETUP FOR A PERIOD OF HVY SNOW NEAR LAKE SUPERIOR AS WINDS SWING SHARPLY AND STRONGLY TO THE NW. WILL LIKELY BE A HEADLINE EVENT FOR MOST IF NOT ALL OF THE COUNTIES BORDERING LAKE SUPERIOR. TEMPS WILL RISE LITTLE OVER THE W WITH EARLY FROPA. OVER THE WEEKEND AND INTO EARLY NEXT WEEK...THE COLDEST AIR OF THE SEASON WILL SETTLE OVER THE AREA. ACTUALLY...THE COLD WILL RIVAL SOME OF THE COLDEST OUTBREAKS DURING THE LAST 10 YEARS. MEDIUM RANGE MODELS FOR OVER A WEEK HAVE BEEN INDICATING THIS SCENARIO...AND IT IS NOW ONLY THE EXACT DETAILS OF HOW COLD IT WILL GET THAT REMAIN IN QUESTION. CONSENSUS OF THE LAST FEW DAYS OF ECWMF/GFS RUNS IS THAT 850MB TEMPS WILL BOTTOM OUT IN THE -28 TO -32C RANGE LATE IN THE WEEKEND. NOGAPS AND SEVERAL RECENT LOCAL HEMISPHERIC WRF-ARW RUNS HAVE INDICATED 850MB TEMPS OF -34C TO AS LOW AS -38C. IT IS VERY RARE TO SEE AIR THAT COLD HERE...SO THOSE SOLUTIONS ARE VIEWED AS OUTLIER SOLUTIONS FOR NOW. IN ANYCASE...SAT THRU TUE WILL BE AN EXTREMELY COLD PERIOD...ESPECIALLY SAT/SUN/MON. IT IS CERTAINLY POSSIBLE THAT SOME LOCATIONS OVER THE W HALF OF UPPER MI AWAY FROM LAKE SUPERIOR INFLUENCE WILL SEE TEMPS REMAIN BLO ZERO FROM FRI NIGHT UNTIL TUE AFTN. MIN TEMPS WILL DEPEND ON CLOUD COVER/WINDS...BUT -10F TO -20F SHOULD BE THE RULE AWAY FROM LAKE SUPERIOR INFLUENCE. IF SFC HIGH PRES RIDGE CAN SETTLE OVER THE AREA ONE NIGHT EARLY NEXT WEEK...MIN TEMPS IN THE USUAL WEST HALF COLD SPOTS WOULD EASILY PLUMMET BLO -30F. WINDS DON`T LOOK TOO STRONG THRU THE PERIOD...SO WIND CHILLS WON`T BE AS LOW AS COULD BE THE CASE. AS FOR LAKE EFFECT...GFS FCST SOUNDINGS ARE ACTUALLY FAIRLY MOIST WITH HIGH INVERSIONS 8KFT TO AS MUCH AS 15KFT. HOWEVER...AN OVERWHELMING NEGATIVE FOR SIGNIFICANT SNOW IS THE VERY COLD AIR WHICH WILL SEVERELY LIMIT SNOW CRYSTAL GROWTH AND THUS ACCUMULATIONS. ALTHOUGH ACCUMULATIONS ARE EXPECTED TO BE FAIRLY LIGHT EACH DAY...DURING SNOW SHOWERS THE AIR WILL BE THICK WITH SMALL SNOWFLAKES WHICH WILL BE EXTREMELY EFFECTIVE AT REDUCING VISIBILITY TO NEAR ZERO. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 1 PM TODAY MIZ003. LAKE EFFECT SNOW WARNING UNTIL 1 PM TODAY MIZ006-007. LAKE EFFECT SNOW ADVISORY UNTIL 1 PM TODAY MIZ001. && $$ AJ (UPDATE) ROLFSON (PREV DISCUSSION) mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1035 PM EST TUE JAN 30 2007 .UPDATE... MAIN FCST CONCERN IS LOCATION/STRENGTH OF LES BANDS. RADAR INDICATED A PROMINENT WEST TO EAST LES BAND FROM JUST SOUTH OF STANNARD ROCK TO WHITEFHISH POINT. SIGNFICANT LOW LVL CONVERGENCE WAS EVIDENT WITH W OR SW WINDS FROM MARQUETTE TO GRAND MARAIS AND NW WINDS FROM THE KEWEENAW AND STANNARD ROCK. OVER THE WEST...SFC OBS SUGGEST LOW LVL CONV WAS FOCUSED BETWEEN ONTONAGON AND KCMX. 00Z TAMDAR SNDG SHOWED TEMPS TO NEAR -19C AT 850 MB (5K FT) INVERSION WHILE UPSTREAM KDLH SNDG SHOWED A LOWER INVERSION(AROUND 900 MB) AND A SIGNIFICANTLY DRIER PROFILE. MESO MODELS SHOWED SLIGHTLY DIFFERENT POSITION FOR BEST LOW LVL CONV AND LIKELY LOCATION FOR STRONGEST LES OVER THE WEST. THE NAM CONTINUED TO FOCUS LES BAND FARTHER NORTH...INTO HOUGHTON...THAN THE LAPS WRF-ARW (JUST N OF M-38) OR THE RUC13(SOUTH OF M-38). THE GOING FCST ADEQUATELY REFLECTS POTENTIAL FOR 3-6 INCH FROM ROCKLAND TO CALUMET. HOWEVER...ONLY MORE LOCALIZED HEAVIER AMOUNTS ARE EXPECTED...MOST LIKELY S OF HOUGHTON. RADAR TREND AND MESO MODELS STILL SUGGEST SIGNFICANT LES POTENTIAL ALONG THE LAKE SUPERIOR SHORE E OF GRAND MARAIS THAT EVENTUALLY WOULD SAG FARTHER S INTO ERN ALGER COUNTY AND NRN LUCE COUNTY BY DAYBREAK. AGAIN...THERE IS LITTLE NEED AT THIS POINT TO ALTER GOING FCST AS POTENTIAL REMAINS FOR LOCAL 4-8 INCH AMOUNTS BY DAYBREAK. && JLB .PREV DISCUSSION...ISSUED 325 PM EST TUE JAN 30 2007 ...ARCTIC AIR TO INVADE WEST AND CENTRAL UPPER MICHIGAN THIS WEEKEND... .SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED UPPER TROUGHING COVERING MUCH OF SE CANADA INTO THE GREAT LAKES...WITH THE CENTER BEING A 498 DAM POLAR VORTEX OVER HUDSON BAY. ON THE WEST SIDE OF THE VORTEX WAS A SHRTWV OVER FAR NORTHERN ONTARIO... ACCOMPANIED BY A 90 KT JET STREAK NEAR THE TROPOPAUSE. THIS SHRTWV IS ALSO ASSOCIATED WITH A LOW PRESSURE TROUGH...WHICH EXTENDS FROM NE MANITOBA INTO NORTHERN ONTARIO JUST N OF PICKLE LAKE. ALTHOUGH 12Z SOUNDINGS FROM NEARBY CANADIAN RAOBS DO NOT INDICATE A LOT OF MOISTURE WITH THE SHRTWV...SURFACE OBS AND VISIBLE SATELLITE IMAGERY DOES SHOW A STRATUS DECK ALONG AND BEHIND THIS TROUGH...WITH OVERCAST CEILINGS BETWEEN 5000-8000 FT. EVEN A LITTLE LIGHT SNOW HAS BEEN REPORTED...WITH A 2 1/2 SM VISIBILITY RECENTLY AT PICKLE LAKE. 850MB TEMPS ARE STILL CHILLY NEAR THIS TROUGH...WITH THE PICKLE LAKE ONTARIO 12Z SOUNDING REPORTING AROUND -17C. CLOSER TO HOME...A 1018MB HIGH PRESSURE RIDGE AXIS IS BUILDING OVER UPPER MICHIGAN... WHICH EXTENDS WESTWARD TO A 1034MB HIGH CENTERED OVER NEBRASKA. THE COMBINATION OF DRIER AIR (SEE 12Z INL SOUNDING) AND DEVELOPING ANTICYCLONIC FLOW ASSOCIATED WITH THE SURFACE RIDGE HAS HELPED TO GREATLY DIMINISH THE LAKE EFFECT SNOW FROM WHAT OCCURRED LAST NIGHT. HOWEVER...WEAK RETURN FLOW ON THE BACK SIDE OF THE RIDGE AXIS HAS ALLOWED LAKE EFFECT TO RAPIDLY DEVELOP ON WESTERN LAKE SUPERIOR. FARTHER TO THE WEST...A STRONG SHRTWV CAN BE SEEN DIVING SOUTHWARD THROUGH SASKATCHEWAN ON THE EAST SIDE OF A VERY AMPLIFIED RIDGE WHEICH EXTENDS UP INTO ALASKA. ON THE NORTH SIDE OF THIS RIDGE OVER THE ARCTIC OCEAN IS YET A STRONGER SHRTWV...AND THIS IS THE ONE THAT WILL BRING THE ARCTIC AIR IN FOR THE WEEKEND. && .SHORT TERM (TONIGHT AND WED)... MAIN FORECAST CONCERN IS LES WITH APPROACHING SHRTWV. WINDS CONTINUING TO BACK TO THE WEST...ALONG WITH THE APPROACHING SHRTWV AND SURFACE TROUGHS...WILL SET UP AN INTERESTING SCENARIO FOR TONIGHT. AS TEMPERATURES COOL DOWN THIS EVENING IN THE INTERIOR AND OVER ONTARIO...LAND BREEZES ARE LIKELY TO SET UP. THESE LAND BREEZES WILL HELP TO FOCUS STRONG CONVERGENCE ALONG THE SURFACE TROUGH...WHICH IS PROGGED TO REACH THE KEWEENAW PENINSULA AND THE LAKE SUPERIOR SHORELINE NEAR GRAND MARAIS AROUND 03Z. THIS CONVERGENCE...COMBINED WITH PLENTY OF OVER-WATER INSTABILITY (AS NOTED WITH PICKLE LAKES RAOB) AND SYNOPTIC MOISTURE SHOULD HELP GENERATE SOME HEAVY LES...ESPECIALLY SINCE THE OMEGA INDUCED FROM THE LAKE EFFECT WILL INTERSECT A 50-75MB DEEP SNOW GROWTH LAYER PER MODEL SOUNDINGS. EXACTLY HOW STRONG THE LAND BREEZE IS WILL DICTATE HOW FAR SOUTH THE CONVERGENCE AND HEAVY SNOW GOES...PARTICULARLY IN THE WESTERN U.P. THE 13 KM RUC...WHICH HAS HAD A GOOD HANDLE ON LATEST LES EVENTS...SUGGESTS THE BAND WILL FOCUS IN THE AREA BETWEEN ROCKLAND AND BARAGA. HOWEVER THE NAM...REGIONAL CANADIAN AND LOCAL HIGH RESOLUTION WRF RUNS KEEP THE BAND FARTHER NORTH...ACROSS PAINESDALE AND HOUGHTON. THE LATEST 15Z AND 18Z RUC RUNS APPEAR TO BE FOLLOWING THE NAM SCENARIO TOO. SINCE ALL SOLUTIONS SEEM PLAUSIBLE...HAVE DECIDED TO FOLLOW A COMPROMISE. WHEREVER IT SETS UP...IT WILL LIKELY REMAIN NEARLY STATIONARY FOR 9 TO 12 HOURS BEFORE THE CONVERGENCE ZONE MOVES NORTHWARD...AND GIVEN GREAT SNOW GROWTH ON MODEL SOUNDINGS...DECIDED TO HOIST WARNINGS EARLIER FOR NE ONTONAGON AND NORTHERN HOUGHTON COUNTIES. ADVISORIES ARE POSTED FOR KEWEENAW AND SOUTHERN HOUGHTON FOR BOTH UNCERTAINTY REGARDING BAND PLACEMENT AND POSSIBLE OTHER BANDS THAT ARE AIDED BY UPSLOPE. KEWEENAW COUNTY WILL NEED TO BE WATCHED A LITTLE MORE TOMORROW AS THE CONVERGENCE ZONE MAY GET STUCK THERE. DECIDED NOT TO GO WITH A WARNING...THOUGH...AS THE CONVERGENCE WEAKENS DRAMATICALLY FROM THAT OBSERVED TONIGHT. FOR THE EASTERN CWA...UPGRADED THE WATCH EARLIER TO A WARNING AS MODELS ARE IN GOOD AGREEMENT HERE WITH THE CONVERGENCE AREA. LOCAL HIGH RESOLUTION WRF RUN SUGGESTS UP TO 0.60 OF QPF UNDER THIS CONVERGENCE...WHICH GIVEN RECENT SNOW TO WATER RATIOS WOULD SUGGEST UP TO 18 INCHES OF SNOW. DID NOT GO THIS HIGH AT THE PRESENT TIME...BUT IT WOULD NOT BE A SURPRISE IF AMOUNTS THAT HIGH OCCUR...ESPECIALLY GIVEN EXTRA CONVERGENCE HELP FROM LAND BREEZES OFF ONTARIO. AWAY FROM THE LES DURING THE SHORT TERM PERIOD...CONDITIONS LOOK FAIRLY QUIET. ALTHOUGH THE STRATUS DECK OVER ONTARIO IS EXPECTED TO MOVE OVER THE CWA THIS EVENING...MUCH OF THE SHRTWV FORCING WHICH HAS HELPED PRODUCE THE LIGHT SNOW AT PICKLE LAKE IS PROGGED TO MOVE OFF TO THE E. THEREFORE HAVE REMOVED ANY SLIGHT CHANCE POPS FOR SYNOPTIC SNOW. ALSO REMOVED POPS FOR SYNOPTIC SNOW ON WED SINCE MUCH OF THE CWA IS PROGGED TO BE IN WEAK SHRTWV RIDGING BETWEEN TONIGHTS SHRTWV AND THE SASKATCHEWAN SHRTWV TROUGH. GOING FORECAST TEMPERATURES THROUGH WED LOOK REASONABLE AND HAVE MADE VERY FEW CHANGES TO THEM. .LONG TERM (WED NIGHT THROUGH NEXT TUE)... ON WED NGT...SHRTWV TROF/DEEPER MSTR WL BE PUSHING TO THE E WED NGT...AND GUIDANCE SHOWS LLVL FLOW VEERING MORE W OVERNGT W-E IN ITS WAKE AND GRDLY BECMG MORE ACYC WITH APRCH OF SHRTWV RDGING/DNVA/ H85-5 QVECTOR DVGC. THESE EVENTS SHOULD CAUSE LES BANDS NEAR THE TIP OF THE KEWEENAW TO MIGRATE TO THE S IN LINE WITH GFS/NAM FCST SHARPER LLVL CNVGC. HOWEVER...SHIFTING WINDS/MORE TRANSIENT CNVGC/ NEGATIVE DYNAMICS MIGHT LIMIT SN ACCUMULATION WED NGT. WL GO WITH LIKELY POPS OVER THE W FM ONTONAGON COUNTY TO THE N. SINCE GUIDANCE SHOWS FOCUSED LLVL CNVGC REMAINING TO THE N OF THE ERN ZNS...WL GO WITH JUST CHC POPS NR LK SUP E OF P53. OTRW...ANY PTCHY -SN/ FLURRIES ACCOMPANYING SHRTWV WL TEND TO DIMINISH OVERNGT ONCE DEEPER MSTR/DYNAMICS EXIT TO THE E. PREFER LOWER GOING FCST MIN TEMPS WITH PROSPECT OF DRYING ALF LATE AS SHOWN ON GFS FCST SDNGS EVEN THOUGH BKN-OVC SC SHOULD LINGER UNDER DVLPG SUBSIDENCE INVRN. EXPECT A RELATIVELY QUIET DAY ON THU UNDER WEAK SHRTWV RDG DOWNSTREAM OF A DEEPENING TROF IN THE NRN PLAINS AND LLVL FLOW SLOWLY BACKING MORE SW. EVEN THOUGH QUITE A BIT OF SC WL LINGER UNDER MID LVL DRY AIR/SUBSIDENCE INVRN SHOWN ON GFS FCST SDNGS....WL RESTRICT MENTION OF POPS ON THU TO AREAS DOWNWIND OF LK SUP IN EXPECTED WSW FLOW. PREFER SOMEWHAT LOWER GFS MOS TEMPS GIVEN EXPECTED CLD COVER/H85 TEMPS -15C TO -17C OR SO. AS SHRTWV FM THE NRN PLAINS MOVES INTO THE UPR MS VALLEY BY 12Z FRI AND THEN INTO ERN LK SUP BY 00Z FRI ACCOMPANINED BY SOME FAIRLY HEALTHY DPVA/H85-5 QVECTOR CNVGC/12 HR H5 HGT FALLS APRCHG 80M... EXPECT A RELATIVELY WDSPRD SN TO DVLP...WITH THE HEAVIEST SN FALLING OVER THE NW HALF OF THE FA ON CYC SIDE OF H5 VORT TRACK WHERE LLVL NW FLOW WL OFFER THE OPPORTUNITY FOR SOME LK ENHANCEMENT AS H85 TEMPS TUMBLE IN THE AFTN AND GFS FCST SDNGS SHOW DEEP MSTR THRU THE TROP. DECIDED TO BUMP POPS UP TO LIKELY EVERYWHERE WITH CATEGORICAL POPS FM IWD-CMX-HURON MTNS ON FRI. LATER SHIFTS WL LIKELY NEED TO ISSUE HEADLINE FOR THIS EVENT EVEN THOUGH LATEST NCEP FCST SN AMTS JUST A FEW INCHES. BITTER COLD WL BE THE MAIN WX STORY THIS WEEKEND/EARLY NEXT WEEK IN PERSISENT HI AMPLITUDE NEGATIVE NAO/POSTIVE PNA DEEP UPR TROF CENTERED BTWN ERN PAC RDG NOSING INTO AK AND BLOCKING UPR HI IN THE N ATLANTIC OCEAN. ALTHOUGH THERE ARE SOME SLGT TIMING DIFFERENCES... 00Z>12Z MID RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT WITH 0Z GFS REFCST ENSEMBLE MEAN DEPICTING SFC LO CROSSING LK SUP ON FRI (SEE ABV) IN ADVANCE OF INCOMING WAVE OF ARCTIC AIR. CORE OF ARCTIC COLD WITH H85 TEMPS IN THE -28C TO -32C RANGE FCST BY BOTH 06Z GFS/12Z ECMWF TO INVADE SAT AND PERSIST INTO TUE. GFS REFCST ENSEMBLE MEAN SHOWS AVERAGE H1000-5 THKNS ARND 488DM WITH H85 TEMPS FCST IN EXCESS OF 2 STANDARD DEVIATIONS BLO NORMAL. AS A COMPARISON TO RECENT COLD WAVES...H85 TEMPS IN THE EARLY FEB 1996 COLD WAVE WERE -30C TO -35C...SO THIS EVENT MAY END UP MARGINALLY WARMER THAN THE COLD OBSVD IN EARLY FEB 1996. GIVEN AGREEMENT AMONG OPS MODELS/ENSEMBLE MEAN...WL GO TOWARD THE LO END OF GFS MOS GUIDANCE FOR THE WEEKEND/EARLY NEXT WEEK... WITH SOME MIN TEMPS AOB -30F/MAX TEMPS REMAINING BLO 0F A GOOD BET FOR INTERIOR AREAS. ALTHOUGH LES WL BE ONGOING NR LK SUP WITH CORE OF COLD PASSING OVER LK SUP ESPECIALLY IN NW FLOW BELTS TO THE S OF LK INDUCED TROF NR LK SUP...SUCH FRIGID TEMPS WL NOT BE CONDUCIVE FOR FVRBL SN GROWTH. COORDINATED WITH GRB. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING 7 PM THIS EVENING TO 1 PM WED MIZ002-003 LAKE EFFECT SNOW WARNING 10 PM THIS EVENING TO 1 PM WED MIZ006-007 LAKE EFFECT SNOW ADVISORY 7 PM THIS EVENING TO 1 PM WED MIZ001 LAKE EFFECT SNOW ADVISORY 7 PM THIS EVENING TO 10 AM WED MIZ084 HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. && $$ AJ (SHORT TERM) KC (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 325 PM EST TUE JAN 30 2007 ...ARCTIC AIR TO INVADE WEST AND CENTRAL UPPER MICHIGAN THIS WEEKEND... .SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED UPPER TROUGHING COVERING MUCH OF SE CANADA INTO THE GREAT LAKES...WITH THE CENTER BEING A 498 DAM POLAR VORTEX OVER HUDSON BAY. ON THE WEST SIDE OF THE VORTEX WAS A SHRTWV OVER FAR NORTHERN ONTARIO... ACCOMPANIED BY A 90 KT JET STREAK NEAR THE TROPOPAUSE. THIS SHRTWV IS ALSO ASSOCIATED WITH A LOW PRESSURE TROUGH...WHICH EXTENDS FROM NE MANITOBA INTO NORTHERN ONTARIO JUST N OF PICKLE LAKE. ALTHOUGH 12Z SOUNDINGS FROM NEARBY CANADIAN RAOBS DO NOT INDICATE A LOT OF MOISTURE WITH THE SHRTWV...SURFACE OBS AND VISIBLE SATELLITE IMAGERY DOES SHOW A STRATUS DECK ALONG AND BEHIND THIS TROUGH...WITH OVERCAST CEILINGS BETWEEN 5000-8000 FT. EVEN A LITTLE LIGHT SNOW HAS BEEN REPORTED...WITH A 2 1/2 SM VISIBILITY RECENTLY AT PICKLE LAKE. 850MB TEMPS ARE STILL CHILLY NEAR THIS TROUGH...WITH THE PICKLE LAKE ONTARIO 12Z SOUNDING REPORTING AROUND -17C. CLOSER TO HOME...A 1018MB HIGH PRESSURE RIDGE AXIS IS BUILDING OVER UPPER MICHIGAN... WHICH EXTENDS WESTWARD TO A 1034MB HIGH CENTERED OVER NEBRASKA. THE COMBINATION OF DRIER AIR (SEE 12Z INL SOUNDING) AND DEVELOPING ANTICYCLONIC FLOW ASSOCIATED WITH THE SURFACE RIDGE HAS HELPED TO GREATLY DIMINISH THE LAKE EFFECT SNOW FROM WHAT OCCURRED LAST NIGHT. HOWEVER...WEAK RETURN FLOW ON THE BACK SIDE OF THE RIDGE AXIS HAS ALLOWED LAKE EFFECT TO RAPIDLY DEVELOP ON WESTERN LAKE SUPERIOR. FARTHER TO THE WEST...A STRONG SHRTWV CAN BE SEEN DIVING SOUTHWARD THROUGH SASKATCHEWAN ON THE EAST SIDE OF A VERY AMPLIFIED RIDGE WHEICH EXTENDS UP INTO ALASKA. ON THE NORTH SIDE OF THIS RIDGE OVER THE ARCTIC OCEAN IS YET A STRONGER SHRTWV...AND THIS IS THE ONE THAT WILL BRING THE ARCTIC AIR IN FOR THE WEEKEND. && .SHORT TERM (TONIGHT AND WED)... MAIN FORECAST CONCERN IS LES WITH APPROACHING SHRTWV. WINDS CONTINUING TO BACK TO THE WEST...ALONG WITH THE APPROACHING SHRTWV AND SURFACE TROUGHS...WILL SET UP AN INTERESTING SCENARIO FOR TONIGHT. AS TEMPERATURES COOL DOWN THIS EVENING IN THE INTERIOR AND OVER ONTARIO...LAND BREEZES ARE LIKELY TO SET UP. THESE LAND BREEZES WILL HELP TO FOCUS STRONG CONVERGENCE ALONG THE SURFACE TROUGH...WHICH IS PROGGED TO REACH THE KEWEENAW PENINSULA AND THE LAKE SUPERIOR SHORELINE NEAR GRAND MARAIS AROUND 03Z. THIS CONVERGENCE...COMBINED WITH PLENTY OF OVER-WATER INSTABILITY (AS NOTED WITH PICKLE LAKES RAOB) AND SYNOPTIC MOISTURE SHOULD HELP GENERATE SOME HEAVY LES...ESPECIALLY SINCE THE OMEGA INDUCED FROM THE LAKE EFFECT WILL INTERSECT A 50-75MB DEEP SNOW GROWTH LAYER PER MODEL SOUNDINGS. EXACTLY HOW STRONG THE LAND BREEZE IS WILL DICTATE HOW FAR SOUTH THE CONVERGENCE AND HEAVY SNOW GOES...PARTICULARLY IN THE WESTERN U.P. THE 13 KM RUC...WHICH HAS HAD A GOOD HANDLE ON LATEST LES EVENTS...SUGGESTS THE BAND WILL FOCUS IN THE AREA BETWEEN ROCKLAND AND BARAGA. HOWEVER THE NAM...REGIONAL CANADIAN AND LOCAL HIGH RESOLUTION WRF RUNS KEEP THE BAND FARTHER NORTH...ACROSS PAINESDALE AND HOUGHTON. THE LATEST 15Z AND 18Z RUC RUNS APPEAR TO BE FOLLOWING THE NAM SCENARIO TOO. SINCE ALL SOLUTIONS SEEM PLAUSIBLE...HAVE DECIDED TO FOLLOW A COMPROMISE. WHEREVER IT SETS UP...IT WILL LIKELY REMAIN NEARLY STATIONARY FOR 9 TO 12 HOURS BEFORE THE CONVERGENCE ZONE MOVES NORTHWARD...AND GIVEN GREAT SNOW GROWTH ON MODEL SOUNDINGS...DECIDED TO HOIST WARNINGS EARLIER FOR NE ONTONAGON AND NORTHERN HOUGHTON COUNTIES. ADVISORIES ARE POSTED FOR KEWEENAW AND SOUTHERN HOUGHTON FOR BOTH UNCERTAINTY REGARDING BAND PLACEMENT AND POSSIBLE OTHER BANDS THAT ARE AIDED BY UPSLOPE. KEWEENAW COUNTY WILL NEED TO BE WATCHED A LITTLE MORE TOMORROW AS THE CONVERGENCE ZONE MAY GET STUCK THERE. DECIDED NOT TO GO WITH A WARNING...THOUGH...AS THE CONVERGENCE WEAKENS DRAMATICALLY FROM THAT OBSERVED TONIGHT. FOR THE EASTERN CWA...UPGRADED THE WATCH EARLIER TO A WARNING AS MODELS ARE IN GOOD AGREEMENT HERE WITH THE CONVERGENCE AREA. LOCAL HIGH RESOLUTION WRF RUN SUGGESTS UP TO 0.60 OF QPF UNDER THIS CONVERGENCE...WHICH GIVEN RECENT SNOW TO WATER RATIOS WOULD SUGGEST UP TO 18 INCHES OF SNOW. DID NOT GO THIS HIGH AT THE PRESENT TIME...BUT IT WOULD NOT BE A SURPRISE IF AMOUNTS THAT HIGH OCCUR...ESPECIALLY GIVEN EXTRA CONVERGENCE HELP FROM LAND BREEZES OFF ONTARIO. AWAY FROM THE LES DURING THE SHORT TERM PERIOD...CONDITIONS LOOK FAIRLY QUIET. ALTHOUGH THE STRATUS DECK OVER ONTARIO IS EXPECTED TO MOVE OVER THE CWA THIS EVENING...MUCH OF THE SHRTWV FORCING WHICH HAS HELPED PRODUCE THE LIGHT SNOW AT PICKLE LAKE IS PROGGED TO MOVE OFF TO THE E. THEREFORE HAVE REMOVED ANY SLIGHT CHANCE POPS FOR SYNOPTIC SNOW. ALSO REMOVED POPS FOR SYNOPTIC SNOW ON WED SINCE MUCH OF THE CWA IS PROGGED TO BE IN WEAK SHRTWV RIDGING BETWEEN TONIGHTS SHRTWV AND THE SASKATCHEWAN SHRTWV TROUGH. GOING FORECAST TEMPERATURES THROUGH WED LOOK REASONABLE AND HAVE MADE VERY FEW CHANGES TO THEM. .LONG TERM (WED NIGHT THROUGH NEXT TUE)... ON WED NGT...SHRTWV TROF/DEEPER MSTR WL BE PUSHING TO THE E WED NGT...AND GUIDANCE SHOWS LLVL FLOW VEERING MORE W OVERNGT W-E IN ITS WAKE AND GRDLY BECMG MORE ACYC WITH APRCH OF SHRTWV RDGING/DNVA/ H85-5 QVECTOR DVGC. THESE EVENTS SHOULD CAUSE LES BANDS NEAR THE TIP OF THE KEWEENAW TO MIGRATE TO THE S IN LINE WITH GFS/NAM FCST SHARPER LLVL CNVGC. HOWEVER...SHIFTING WINDS/MORE TRANSIENT CNVGC/ NEGATIVE DYNAMICS MIGHT LIMIT SN ACCUMULATION WED NGT. WL GO WITH LIKELY POPS OVER THE W FM ONTONAGON COUNTY TO THE N. SINCE GUIDANCE SHOWS FOCUSED LLVL CNVGC REMAINING TO THE N OF THE ERN ZNS...WL GO WITH JUST CHC POPS NR LK SUP E OF P53. OTRW...ANY PTCHY -SN/ FLURRIES ACCOMPANYING SHRTWV WL TEND TO DIMINISH OVERNGT ONCE DEEPER MSTR/DYNAMICS EXIT TO THE E. PREFER LOWER GOING FCST MIN TEMPS WITH PROSPECT OF DRYING ALF LATE AS SHOWN ON GFS FCST SDNGS EVEN THOUGH BKN-OVC SC SHOULD LINGER UNDER DVLPG SUBSIDENCE INVRN. EXPECT A RELATIVELY QUIET DAY ON THU UNDER WEAK SHRTWV RDG DOWNSTREAM OF A DEEPENING TROF IN THE NRN PLAINS AND LLVL FLOW SLOWLY BACKING MORE SW. EVEN THOUGH QUITE A BIT OF SC WL LINGER UNDER MID LVL DRY AIR/SUBSIDENCE INVRN SHOWN ON GFS FCST SDNGS....WL RESTRICT MENTION OF POPS ON THU TO AREAS DOWNWIND OF LK SUP IN EXPECTED WSW FLOW. PREFER SOMEWHAT LOWER GFS MOS TEMPS GIVEN EXPECTED CLD COVER/H85 TEMPS -15C TO -17C OR SO. AS SHRTWV FM THE NRN PLAINS MOVES INTO THE UPR MS VALLEY BY 12Z FRI AND THEN INTO ERN LK SUP BY 00Z FRI ACCOMPANINED BY SOME FAIRLY HEALTHY DPVA/H85-5 QVECTOR CNVGC/12 HR H5 HGT FALLS APRCHG 80M... EXPECT A RELATIVELY WDSPRD SN TO DVLP...WITH THE HEAVIEST SN FALLING OVER THE NW HALF OF THE FA ON CYC SIDE OF H5 VORT TRACK WHERE LLVL NW FLOW WL OFFER THE OPPORTUNITY FOR SOME LK ENHANCEMENT AS H85 TEMPS TUMBLE IN THE AFTN AND GFS FCST SDNGS SHOW DEEP MSTR THRU THE TROP. DECIDED TO BUMP POPS UP TO LIKELY EVERYWHERE WITH CATEGORICAL POPS FM IWD-CMX-HURON MTNS ON FRI. LATER SHIFTS WL LIKELY NEED TO ISSUE HEADLINE FOR THIS EVENT EVEN THOUGH LATEST NCEP FCST SN AMTS JUST A FEW INCHES. BITTER COLD WL BE THE MAIN WX STORY THIS WEEKEND/EARLY NEXT WEEK IN PERSISENT HI AMPLITUDE NEGATIVE NAO/POSTIVE PNA DEEP UPR TROF CENTERED BTWN ERN PAC RDG NOSING INTO AK AND BLOCKING UPR HI IN THE N ATLANTIC OCEAN. ALTHOUGH THERE ARE SOME SLGT TIMING DIFFERENCES... 00Z>12Z MID RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT WITH 0Z GFS REFCST ENSEMBLE MEAN DEPICTING SFC LO CROSSING LK SUP ON FRI (SEE ABV) IN ADVANCE OF INCOMING WAVE OF ARCTIC AIR. CORE OF ARCTIC COLD WITH H85 TEMPS IN THE -28C TO -32C RANGE FCST BY BOTH 06Z GFS/12Z ECMWF TO INVADE SAT AND PERSIST INTO TUE. GFS REFCST ENSEMBLE MEAN SHOWS AVERAGE H1000-5 THKNS ARND 488DM WITH H85 TEMPS FCST IN EXCESS OF 2 STANDARD DEVIATIONS BLO NORMAL. AS A COMPARISON TO RECENT COLD WAVES...H85 TEMPS IN THE EARLY FEB 1996 COLD WAVE WERE -30C TO -35C...SO THIS EVENT MAY END UP MARGINALLY WARMER THAN THE COLD OBSVD IN EARLY FEB 1996. GIVEN AGREEMENT AMONG OPS MODELS/ENSEMBLE MEAN...WL GO TOWARD THE LO END OF GFS MOS GUIDANCE FOR THE WEEKEND/EARLY NEXT WEEK... WITH SOME MIN TEMPS AOB -30F/MAX TEMPS REMAINING BLO 0F A GOOD BET FOR INTERIOR AREAS. ALTHOUGH LES WL BE ONGOING NR LK SUP WITH CORE OF COLD PASSING OVER LK SUP ESPECIALLY IN NW FLOW BELTS TO THE S OF LK INDUCED TROF NR LK SUP...SUCH FRIGID TEMPS WL NOT BE CONDUCIVE FOR FVRBL SN GROWTH. COORDINATED WITH GRB. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING 7 PM THIS EVENING TO 1 PM WED MIZ002-003 LAKE EFFECT SNOW WARNING 10 PM THIS EVENING TO 1 PM WED MIZ006-007 LAKE EFFECT SNOW ADVISORY 7 PM THIS EVENING TO 1 PM WED MIZ001 LAKE EFFECT SNOW ADVISORY 7 PM THIS EVENING TO 10 AM WED MIZ084 HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. && $$ AJ (SHORT TERM) KC (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1207 PM EST TUE JAN 30 2007 .SYNOPSIS... 16Z WATER VAPOR LOOP...RUC 500MB HEIGHT ANALYSIS AND 12Z RAOBS SHOWED UPPER TROUGHING COVERING MUCH OF SE CANADA INTO THE GREAT LAKES...WITH THE CENTER BEING A 498 DAM POLAR VORTEX OVER HUDSON BAY. ON THE WEST SIDE OF THE VORTEX WAS A SHRTWV OVER FAR NORTHERN ONTARIO...ACCOMPANIED BY A 90 KT JET STREAK NEAR THE TROPOPAUSE. THIS SHRTWV IS ALSO ASSOCIATED WITH A LOW PRESSURE TROUGH...WHICH EXTENDS FROM NE MANITOBA INTO NORTHERN ONTARIO JUST N OF PICKLE LAKE. ALTHOUGH 12Z SOUNDINGS FROM NEARBY CANADIAN RAOBS DO NOT INDICATE A LOT OF MOISTURE WITH THE SHRTWV...SURFACE OBS AND VISIBLE SATELLITE IMAGERY DOES SHOW A STRATUS DECK ALONG AND BEHIND THIS TROUGH...WITH OVERCAST CEILINGS BETWEEN 5000-8000 FT. 850MB TEMPS ARE STILL CHILLY NEAR THIS TROUGH...WITH THE PICKLE LAKE ONTARIO SOUNDING REPORTING AROUND -17C. CLOSER TO HOME...A 1018MB HIGH PRESSURE RIDGE AXIS IS BUILDING INTO UPPER MICHIGAN FROM LAKE SUPERIOR...WHICH EXTENDS OFF A 1034MB HIGH CENTERED OVER NEBRASKA. THE COMBINATION OF DRIER AIR (SEE 12Z INL SOUNDING) AND DEVELOPING ANTICYCLONIC FLOW ASSOCIATED WITH THE SURFACE RIDGE HAS HELPED TO GREATLY DIMINISH THE LAKE EFFECT SNOW FROM WHAT OCCURRED LAST NIGHT. IN FACT...ALMOST ALL OF WESTERN LAKE SUPERIOR IS CLEAR WITH BANDS ONLY EXTENDING OUT ABOUT 25 MILES OFFSHORE. NONETHELESS...WITH THE GREATER FETCH LENGTH OF NORTHWEST WINDS ON EASTERN LAKE SUPERIOR TO HELP WITH MOISTENING... SOME BANDS STILL CONTAIN 24-28DBZ REFLECTIVITIES ON THE CURRENT RADAR LOOP. && .UPDATE... MAIN UPDATE CONCERN IS DEVELOPING LES TONIGHT FOR THIS AFTERNOON...WIND FLOW SHOULD CONTINUE TO BACK TOWARDS THE WEST AS BOTH THE SHRTWV AND SURFACE TROUGH OVER NORTHERN ONTARIO...AND THE HIGH PRESSURE RIDGE OVER LAKE SUPERIOR...DRIFT SOUTH. THIS SHOULD CAUSE THE BANDS OVER THE EASTERN CWA TO CONTINUE MOVING EASTWARD...THEN LIFT OUT OVER LAKE SUPERIOR LATE WHEN THE WIND IS PROGGED TO TURN DUE WEST. GOING FORECAST HAS THE SCENARIO HANDLED WELL AND ONLY A FEW MINOR TWEAKS WERE MADE TO THE SNOW COVERAGE AREA BASED ON RADAR TRENDS. THE WIND SWITCHING TO THE WEST...ALONG WITH THE APPROACHING SHRTWV AND SURFACE TROUGHS...SETS UP AN INTERESTING SCENARIO FOR TONIGHT. AS TEMPERATURES COOL DOWN THIS EVENING IN THE INTERIOR AND OVER ONTARIO...LAND BREEZES ARE LIKELY TO SET UP. THESE LAND BREEZES WILL HELP TO FOCUS STRONG CONVERGENCE ALONG THE SURFACE TROUGH...WHICH IS PROGGED TO REACH THE KEWEENAW PENINSULA AND THE LAKE SUPERIOR SHORELINE NEAR GRAND MARAIS AROUND 03Z. THIS CONVERGENCE...COMBINED WITH PLENTY OF OVER-WATER INSTABILITY (AS NOTED WITH PICKLE LAKES RAOB) AND SYNOPTIC MOISTURE SHOULD HELP GENERATE SOME HEAVY LES...ESPECIALLY SINCE THE OMEGA INDUCED FROM THE LAKE EFFECT WILL INTERSECT A 50-75MB DEEP SNOW GROWTH LAYER PER MODEL SOUNDINGS. EXACTLY HOW STRONG THE LAND BREEZE IS WILL DICTATE HOW FAR SOUTH THE CONVERGENCE AND HEAVY SNOW GOES...PARTICULARLY IN THE WESTERN U.P. THE 13 KM RUC...WHICH HAS HAD A GOOD HANDLE ON LATEST LES EVENTS...SUGGESTS THE BAND WILL FOCUS IN THE AREA BETWEEN ROCKLAND AND BARAGA. HOWEVER THE NAM AND LOCAL HIGH RESOLUTION WRF RUNS KEEP THE BAND FARTHER NORTH...ACROSS PAINESDALE AND HOUGHTON. THE LATEST 15Z RUC APPEARS TO BE FOLLOWING THE NAM SCENARIO TOO. SINCE ALL SOLUTIONS SEEM PLAUSIBLE...HAVE DECIDED TO FOLLOW A COMPROMISE. WHEREVER IT SETS UP...IT WILL LIKELY REMAIN NEARLY STATIONARY FOR 9 TO 12 HOURS BEFORE THE CONVERGENCE ZONE MOVES NORTHWARD...AND GIVEN GREAT SNOW GROWTH ON MODEL SOUNDINGS...DECIDED TO HOIST WARNINGS FOR NE ONTONAGON AND NORTHERN HOUGHTON COUNTIES. ADVISORIES ARE POSTED FOR KEWEENAW AND SOUTHERN HOUGHTON FOR BOTH UNCERTAINTY REGARDING BAND PLACEMENT AND POSSIBLE OTHER BANDS THAT ARE AIDED BY UPSLOPE. FOR THE EASTERN CWA...UPGRADED THE WATCH TO A WARNING AS MODELS ARE IN GOOD AGREEMENT HERE WITH THE CONVERGENCE AREA. LOCAL HIGH RESOLUTION WRF RUN SUGGESTS UP TO 0.60 OF QPF UNDER THIS CONVERGENCE...WHICH GIVEN RECENT SNOW TO WATER RATIOS WOULD SUGGEST UP TO 18 INCHES OF SNOW. DID NOT GO THIS HIGH AT THE PRESENT TIME...BUT IT WOULD NOT BE A SURPRISE IF AMOUNTS THAT HIGH OCCUR...ESPECIALLY GIVEN EXTRA CONVERGENCE HELP FROM LAND BREEZES OFF ONTARIO. .PREV DISCUSSION... LARGE SCALE SHOWS RIDGE OVER PACIFIC COAST INTO WESTERN CANADA AND ALASKA WHILE TROUGHING DOMINATES EASTERN CANADA INTO GREAT LAKES. THIS PATTERN WILL STAY AROUND FOR FORSEEABLE FUTURE. TROUGH ONLY DEEPENS LATE THIS WEEK INTO THE WEEKEND AND MOST LIKELY STAYING THAT WAY UNTIL EARLY NEXT WEEK. VERY COLD AIR WILL DECEND INTO MUCH OF THE CONUS...INCLUDING THE UPR GREAT LAKES REGION. SHORTWAVE THAT HAS PRODUCED STEADY LIGHT SNOW OVR MAINLY SOUTH CWA SINCE YDY AFTN IS MOVING INTO N LWR MI. SHORTWAVE AND DEEP MOISTURE WITH IT ALLOWED LK EFFECT SNOW SHOWERS TO INTENSIFY TREMENDOUSLY SINCE LATE LAST EVENING. HOWEVER...BANDS OF MOST INTENSE SNOW ARE ISOLATED. ONE BAND WAS AFFECTING SW SCHOOLCRAFT COUNTY FOR MUCH OF NIGHT. NOTHING HEARD FM THIS AREA YET...BUT WITH ECHOES PINGING 12KFT ON MQT RADAR OUT OVR N LK MI STAYING STATIONARY OVR SAME AREA FOR 5 HOURS OR SO SUGGESTS THAT AMOUNTS OF A FOOT WOULD NOT BE OUT OF QUESTION. THAT AREA OF ENHANCED SNOW IS BEGINNING TO SHIFT OFFSHORE AS WINDS JUST OFF SFC ARE INCREASING FM NORTH. MEANWHILE...STRONG SNOW BAND OVR LAKE SUPERIOR...THAT PRODUCED 6 INCHES OF SNOW LAST EVENING AT COPPER HARBOR PER LOCAL MEDIA REPORT...MIGRATED SOUTH AND HIT THE HIGHER TERRAIN OF NCNTRL UPR MI WITHIN THE LAST HOUR. BAND WAS PRETTY NARROW...BUT VERY INTENSE...DROPPING 4 INCHES OF SNOW IN ONE HOUR AT THE NWS OFFICE IN NEGAUNEE TOWNSHIP. FORTUNATELY...BAND IS TRANSITORY AND IS SHIFTING STEADILY INLAND. OPTED TO COVER QUICK MOVING BAND WITH SHORT TERM FORECASTS INSTEAD OF AN ADVISORY. EXPECT HEAVIEST SNOW...AIDED BY SYNOPTIC SUPPORT...TO DIMINISH BY MID MORNING IF NOT SOONER. ONLY REAL CHANGE TO PREV GRIDS FOR TODAY WAS TO KEEP LIKELY POPS OVR NE CWA INTO THE AFTN THOUGH SNOW INTENSITY SHOULD GREATLY DIMINISH BY THEN. TURNING TO TONIGHT. SHORTWAVE CURRENTLY NEAR CHURCHILL MANITOBA TRUCKS SSE AND REACHES NE LK SUPERIOR BY LATE TONIGHT. BRIEF PERIOD OF SYNOPTIC UPWARD MOTION AND DEEPER MOISTURE TO 10KFT WILL SPIKE LES AGAIN. GFS APPEARED TOO WEST WITH BLYR WINDS CONSIDERING CLOSENESS OF TROUGH...SO FOLLOWED NAM/RUC13/CAN GEM WITH IDEA OF NW WINDS DEVELOPING ON N HALF OF LK SUPERIOR TOWARD WHITEFISH BAY AND MORE W WINDS REMAINING ON W HALF OF LK SUPERIOR OVR KEWEENAW. THIS RESULTS IN A QUITE STRONG AREA OF CONVERGENCE DEVELOPING OVER FAR NE CWA TOWARD WHITEFISH POINT IN APX CWA. ANY DOMINANT BAND STREAMING INTO THIS AREA WILL ALSO HAVE ADDED BENEFIT OF MAXIMUM OVER WATER FETCH OVR THE STILL OPEN WATERS OF LK SUPERIOR. ONE OR TWO BANDS OF HEAVY SNOW SEEM PROBABLE IN THESE AREAS WITH SNOWFALL RATES SIMILAR TO THOSE SEEN TONIGHT. ALTHOUGH THE AREA IS RELATIVELY SMALL...POTENTIAL FOR LARGE AMOUNTS OF LES ARE THERE. SO...COORD WITH APX AND ISSUED A LK EFFECT SNOW WATCH FOR ALGER AND LUCE COUNTIES TONIGHT INTO WED FOR AREAS MOSTLY EAST OF GRAND MARAIS. FARTHER WEST OVER KEWEENAW...DID NOT GO WITH WATCH DUE TO THAT AREA BEING FARTHER DISPLACED FM SYNOPIC LIFT/MOISTURE AND A SHORTER OVER WATER FETCH. IF CONVERGENCE STRENGTHENS IN VCNTY OF APOSTLE ISLANDS (AS GFS INDICATES) THEN HEAVY SNOW COULD AFFECT PORTIONS OF KEWEENAW PENINSULA AS WELL. JUST HAVE ADVY AMOUNTS IN GRIDS ATTM. WINDS BACKING TO WSW SHOULD PUSH MOST OF HEAVY SNOW OFFSHORE OF ALGER/LUCE BY LATE MORNING ON WED...BUT SNOW SHOWERS WILL CONTINUE ON THE KEWEENAW. ONLY MADE MINOR CHANGES TO WED NIGHT THROUGH FRI FORECAST PERIODS. SOME LIGHT OVERRUNNING SNOW SEEMS POSSIBLE THU-THU NIGHT AHEAD OF PRIMARY SHORTWAVE THAT BEGINS TO BRING IN BITTER COLD AIR LATE FRI. SOME CONCERN THAT FRI AFTN-FRI EVENING PERIOD MAY BE QUITE HAZARDOUS DUE TO A PERIOD OF HEAVY SNOW...INCREASING WINDS...BLOWING SNOW... REDUCED VISIBILITIES. NOT TO MENTION...TUMBLING TEMPERATURES AND NO DOUBT WIND CHILL ISSUES. LOWERED TEMPS IN FRI NIGHT-SAT PERIODS FOR WEST HALF INTERIOR. WINDS BY LATE FRI NIGHT ARE MOSTLY FM WEST WHICH WILL LEAD TO MOSTLY OVER LAND TRAJECTORIES...LIMITING LAKE SUPERIOR MODERATION. THIS SHOULD ALLOW EFFICIENT TRANSPORT OF BITTER COLD AIR BANKED TO THE WEST AND NORTH INTO THE UPR LAKES. MEX GUIDANCE FOR FRI NIGHT SHOWED -10F TO -15F INLAND INTERIOR WHICH SEEMED FEASIBLE AND THAT WOULD LIKELY MEAN SOME LOCALES SAT WILL NOT HIT ZERO INLAND. IN FACT...LATEST GFS...WHICH AGREES WITH THE ECMWF...SHOWS TEMPS AT KIWD REMAINING BLO ZERO FM FRI NIGHT THROUGH MON. WILL CONTINUE TO HIGHLIGHT THE UPCOMING COLD IN HWO. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING 7 PM THIS EVENING TO 1 PM WED MIZ002-003 LAKE EFFECT SNOW WARNING 10 PM THIS EVENING TO 1 PM WED MIZ006-007 LAKE EFFECT SNOW ADVISORY 7 PM THIS EVENING TO 1 PM WED MIZ001 LAKE EFFECT SNOW ADVISORY 7 PM THIS EVENING TO 10 AM WED MIZ084 HEAVY FREEZING SPRAY WARNING EAST 1/2 LAKE SUPERIOR. && $$ AJ (UPDATE) JLA (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 335 PM CST WED JAN 31 2007 .DISCUSSION... BAND OF SNOW WITH FAIRLY SIG 850-700 MB THETA E ADVECTION AS DEPICTED BUT RUC HAS MOSTLY MOVED OFF INTO WI BUT REMAINS OF UPPER TROF MOVING ACROSS REST OF AREA THIS EVENING. FAIRLY SIG TROP LOWERING WITH THIS TROF..AND SIMILAR FORCING WILL BE MOVING INTO THE AREA BY THURSDAY AFTERNOON AND AGAIN FRIDAY AFTERNOON. WILL FOLLOW THE GFS ON TIMING AND IS VERY CLOSE TO ECMWF/UKMET. THE FIRST BLAST OF COLD AIR ARRIVES THURSDAY NIGHT...BUT THE STRONGER SURGE WILL BE FRIDAY NIGHT...WITH MORE DANGEROUS WIND CHILLS. THE UPPER JET WILL BE CLOSER TO THE AXIS OF STRONG LOW LEVEL COLD ADVECTION ON FRIDAY NIGHT. STILL MAY NEED AN ADVISORY IN WESTERN CWA ON THURSDAY NIGHT WITH THE COLD ADVECTION/WIND CHILLS/BLOWING SNOW POTENTIAL. THE LIKELY POPS STILL LOOK GOOD FOR THE TROUGH THURSDAY AFTERNOON/NIGHT BUT WILL SPEED UP THE ONSET A BIT. HAVE PAINTED IN A SMALL POP/ABOVE GUID/ FOR FRIDAY AFTERNOON/NIGHT BASED ON THE ABOVE MENTIONED FORCING AS WELL. THE ARCTIC AIR REMAINS ENTRENCHED FOR THE FIRST PART OF THE WEEK WITH MOSTLY CLEAR SKIES. HAVE DECREASED CLOUD COVER DRAMATICALLY IN THE SKY GRIDS WITH THE ARCTIC AIR IN PLACE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 830 PM CST WED JAN 31 2007 .DISCUSSION...SO FAR THE FORECAST LOOKS ON TRACK. AFTER AN EARLIER UPDATE TO EXPAND THE ADV AREA FOR THREE MORE COUNTIES THE FORECAST HAS GONE ABOUT AS EXPECTED. MOST PLACES ACROSS NRN MS AND SERN AR HAVE REPORTED SLEET WITH EVEN SOME LIGHT SN AT THE ONSET. THE WAY EVERYTHING IS GOING WE WILL LIKELY NEED TO SEE THE INTENSITY PICK UP BEFORE WE START TO SEE ANY ISSUES ACROSS OUR NORTH. THIS WILL LIKELY HAPPEN IN A FEW HRS AS HEAVIER BANDS OF PRECIP HAVE BEEN WORKING NE THROUGH WRN LOUISIANA FROM THE COAST. LOOK FOR THESE BANDS TO MOVE INTO THE DELTA AREA AROUND 4Z WITH MODERATE SLEET...SNOW TO START. IT STILL LOOKS LIKE THE SRN 2/3RDS OF THE CWA WILL ALL TRANSITION TO LIQUID AFTER MIDNIGHT. THE NRN 3RD COULD BECOME TRICKY AS THE LL WARM PROVIDING MORE OF A CONCERN FOR FZRA AFTER MIDNIGHT. THIS IS ESPECIALLY SO NORTH OF THE HWY 82 CORRIDOR AROUND LOCATIONS LIKE CLEVELAND AND GRENADA WHERE THE RUC SNDGS SHOW THE POSSIBILITY OF FZRA FOR A 3 TO 6 HRS. WILL KEEP AN EYE ON THIS TO SEE IF ANY UPDATES NEED TO BE MADE TO THE FORECAST AND ADV. NO UPDATE NEEDED TO THE ZFP OR GRIDS AT THIS TIME. /CAB/ && .PREV DISCUSSION...ADVISORY ISSUED FOR NRN TIER ZONES FOR WINTER WEATHER TONIGHT. WILL SEE A RAIN/SLEET MIX AS FAR SOUTH AS INTERSTATE 20 TONIGHT BUT THE BEST CHANCE FOR LIGHT ACCUMULATION WILL BE IN THE COLDEST AIR THAT SITS ALONG THE NRN EDGE OF THE FORECAST AREA. A COLD AND VERY DRY AIR MASS HAS SETTLED OVER THE REGION. EVAPORATIVE COOLING WILL PRODUCE FREEZING TEMPERATURES AT AND JUST ABOVE THE SURFACE OVER NRN ZONES AT THE ONSET OF PRECIP THIS EVENING. FREEZING TEMPERATURES IN THE ADVISORY AREA...FROM CLEVELAND TO COLUMBUS...WILL BE DEEP ENOUGH FOR A MIXTURE OF SNOW AND SLEET EARLY TONIGHT. THE TIER FURTHER S WILL SEE RAIN AND SLEET MIXED WITH SNOW AND FREEZING RAIN BUT LITTLE OR NO ACCUMULATION OF WINTER PRECIP IS EXPECTED. WET BULB ZERO TEMPS WILL HOVER IN A LAYER ABOVE THE SURFACE INTO CENTRAL ZONES RESULTING IN THE POSSIBILITY OF A RAIN AND SLEET MIXTURE INTO THE I-20 CORRIDOR BUT SLEET WILL MELT RAPIDLY ON CONTACT WITH THE GROUND. THE ADVECTION OF WARMER AIR AROUND 850 MB AND COOLING OF LOWER LEVELS NEAR THE SURFACE AFTER THE ONSET OF RAIN HAS REQUIRED A VARIED PATTERN OF WEATHER TYPES FROM NORTH TO SOUTH FOR TONIGHT. DIFFERENCES IN FORECAST TEMPERATURES...ESPECIALLY AT THE SURFACE...OF ONLY A DEGREE OR TWO WILL MEAN A POTENTIAL CHANGE IN THE WEATHER TYPE FOR MANY NRN AND CENTRAL ZONES. PRECIP HAS DEVELOPED OVER WRN ZONES THIS AFTERNOON WITH RAIN/SLEET MIXTURE ALREADY REPORTED OVER NE LA. TEMPERATURES WILL BEGIN TO INCREASE BY MIDNIGHT OVER MOST AREAS WHEN THE AIR COLUMN BEGINS TO MOISTEN AND EVAPORATIVE COOLING IS SHUT DOWN. WE WILL MAINTAIN A CHANCE OF A RAIN/SLEET MIX FOR AREAS ALONG AND N OF THE HIGHWAY 82 CORRIDOR AFTER MIDNIGHT BUT MOST OTHER AREAS WILL SEE PRECIP TURN TO ALL RAIN BY OR SHORTLY AFTER MIDNIGHT. RAIN WILL BE WIDESPREAD OVER THE FORECAST AREA BY SUNRISE THURSDAY AND TEMPERATURES WILL BE ABOVE FREEZING ACROSS THE REGION. THE SURFACE TROUGH LIFTS INTO SRN ZONES BY THURSDAY AFTERNOON... POSITIONING THE ASSOCIATED WARM FRONT IN SE MS BY 18Z. WILL MAINTAIN CHANCE OF THUNDERSTORMS THOSE AREAS TOMORROW AFTERNOON BUT THE TRACK LOOKS TOO FAR S TO SUPPORT ENOUGH INSTABILITY FOR SEVERE CONVECTION. UNDERCUT MOS HIGH TEMPS SLIGHTLY FOR TOMORROW CONSIDERING RAIN SHIELD AND SRN EXTENT OF SURFACE TROUGH. THE BOUNDARY IS EXPECTED TO MOVE THROUGH THE AREA BY THURSDAY EVENING. BEHIND THIS SYSTEM...SFC HIGH PRESSURE OVER THE GREAT PLAINS STATES WILL BEGIN TO MOVE INTO THE AREA FROM THE NORTHWEST. ISENTROPIC ANALYSIS AT THE 285-295K LEVEL AND REMAINING MOISTURE (PWATS AROUND 0.5-0.8 INCH) SHOW A SLIGHT CHANCE FOR SHOWERS FOR FRIDAY...MAINLY IN THE MORNING. WENT AHEAD AND STAYED WITH GUI FOR THU NIGHT INTO SATURDAY MORNING. ANY SHOWERS WILL NOT LAST LONG AS THE ECMWF AND GFS BOTH SHOW HIGH PRESSURE AND NORTHWEST FLOW ALOFT TAKING OVER THE REGION TO START CLEARING OVER THE ARKLAMISS BY SATURDAY AFTERNOON. THE ARCTIC AIRMASS THAT IS MOVING INTO THE REGION WILL COMBINE WITH CLEAR SKIES TO ALLOW LOW TEMPERATURES TO AGAIN DIP DOWN INTO THE 20S FOR THE END OF THE WEEKEND INTO THE BEGINNING OF THE WORK WEEK. THE MAIN CHANGES MADE TO TEMPERATURES WERE TO LOWER JUST A BIT ON FRIDAY NIGHT. SKIES WILL BE CLEARING AS HIGH PRESSURE MOVES IN...AND 925MB TEMPS LOOK TO RANGE FROM 0C TO -8C FOR THIS TIME PERIOD. DECIDED TO JUST BUMP TEMPERATURES DOWN A DEGREE OR TWO FOR THIS TIME PERIOD. FOR THE EXTENDED PORTION OF THE FORECAST (PAST SATURDAY NIGHT)...NO MAJOR CHANGES WERE NECESSARY. THE PREVIOUS LONG TERM DISCUSSION FOLLOWS. /14/ PREVIOUS LONG TERM DISCUSSION...THE DOMINANT HUDSON BAY LOW PATTERN WILL CONTINUE TO BRING SEVERAL COLD EPISODES FOR THE NEXT ONE TO TWO WEEKS IN MOSTLY DRY NORTHWEST FLOW. WITHOUT MUCH TO FOCUS ON PRECIP-WISE...THE PRIMARY FORECAST QUESTIONS CONCERN THE INTENSITY OF COLD AS THE FORECAST AREA WILL EXIST ON THE SRN EDGE OF THE POLAR VORTEX. AT THIS TIME...IT LOOKS AS IF THE CENTER OF COLD AIR ANOMALIES WILL STAY NORTH OF THE REGION...BUT THE NEXT FEW SURGES OF COLD AIR WILL BE SHALLOW AND OF TRUE ARCTIC ORIGINS FROM NEAR THE NORTH POLE. GIVEN RECENT GFS PERFORMANCES WITH SUCH AIRMASSES...HAVE OPTED TO TREND TOWARD COOLER GFS MEAN ENSEMBLE GUIDANCE AND CUT MEX GUIDANCE FROM FRIDAY NIGHT ONWARD (AT LEAST FOR PORTIONS OF THE FORECAST AREA). /EC/ && .AVIATION...WIDESPREAD WINTER PRECIP WILL DEVELOP ACROSS THE REGION THIS EVENING ALONG AND NORTH OF INTERSTATE 20 WITH THE BEST COVERAGE OVER AREAS ALONG AND NORTH OF HIGHWAY 82. HAVE RECEIVED REPORTS OF SLEET OVER NE LA AND TVR THIS AFTERNOON AS INITIAL PRECIP AREA MOVES IN. CLOUD HEIGHTS WILL GRADUALLY DROP AS PRECIP INCREASES IN COVERAGE AND INTENSITY TONIGHT WITH MVFR CONDITIONS MANY LOCATIONS BY MIDNIGHT AND IFR CONDITIONS BY SUNRISE. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 36 45 36 51 / 98 97 25 16 MERIDIAN 35 49 37 53 / 100 96 33 16 VICKSBURG 36 42 37 50 / 96 89 25 17 HATTIESBURG 40 53 39 57 / 100 99 29 16 NATCHEZ 38 46 34 53 / 98 91 22 16 GREENVILLE 32 38 33 43 / 99 95 39 18 GREENWOOD 30 39 34 46 / 100 97 37 18 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR MSZ018-019- 025>034. LA...NONE. AR...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR ARZ074-075. && $$ 03/14 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 725 PM CST WED JAN 31 2007 .DISCUSSION...DOING A QUICK UPDATE TO INCLUDE EXTREME SOUTHEASTERN ARKANSAS AND WASHINGTON COUNTY IN THE WINTER WEATHER ADVISORY. CURRENT OBS AND RUC DATA SHOWS THAT FROZEN PRECIP MAY BECOME MORE OF A PROBLEM IN THOSE AREAS. RUC IS NOW SHOWING THE WET BULB ZERO LINE SOUTH TO THE LA BORDER AND DUE EAST ACROSS CENTRAL MS. DECENT PRECIP IS CURRENTLY MOVING ACROSS THE DELTA WITH ANOTHER BATCH OF PRECIP HOT ON ITS HEELS. THIS WILL LIKELY CAUSE HAZARDOUS CONDITIONS ON BRIDGES AND EXPOSED SFCS IN THE NEXT FEW HRS. /CAB/ && .PREV DISCUSSION...ADVISORY ISSUED FOR NRN TIER ZONES FOR WINTER WEATHER TONIGHT. WILL SEE A RAIN/SLEET MIX AS FAR SOUTH AS INTERSTATE 20 TONIGHT BUT THE BEST CHANCE FOR LIGHT ACCUMULATION WILL BE IN THE COLDEST AIR THAT SITS ALONG THE NRN EDGE OF THE FORECAST AREA. A COLD AND VERY DRY AIR MASS HAS SETTLED OVER THE REGION. EVAPORATIVE COOLING WILL PRODUCE FREEZING TEMPERATURES AT AND JUST ABOVE THE SURFACE OVER NRN ZONES AT THE ONSET OF PRECIP THIS EVENING. FREEZING TEMPERATURES IN THE ADVISORY AREA...FROM CLEVELAND TO COLUMBUS...WILL BE DEEP ENOUGH FOR A MIXTURE OF SNOW AND SLEET EARLY TONIGHT. THE TIER FURTHER S WILL SEE RAIN AND SLEET MIXED WITH SNOW AND FREEZING RAIN BUT LITTLE OR NO ACCUMULATION OF WINTER PRECIP IS EXPECTED. WET BULB ZERO TEMPS WILL HOVER IN A LAYER ABOVE THE SURFACE INTO CENTRAL ZONES RESULTING IN THE POSSIBILITY OF A RAIN AND SLEET MIXTURE INTO THE I-20 CORRIDOR BUT SLEET WILL MELT RAPIDLY ON CONTACT WITH THE GROUND. THE ADVECTION OF WARMER AIR AROUND 850 MB AND COOLING OF LOWER LEVELS NEAR THE SURFACE AFTER THE ONSET OF RAIN HAS REQUIRED A VARIED PATTERN OF WEATHER TYPES FROM NORTH TO SOUTH FOR TONIGHT. DIFFERENCES IN FORECAST TEMPERATURES...ESPECIALLY AT THE SURFACE...OF ONLY A DEGREE OR TWO WILL MEAN A POTENTIAL CHANGE IN THE WEATHER TYPE FOR MANY NRN AND CENTRAL ZONES. PRECIP HAS DEVELOPED OVER WRN ZONES THIS AFTERNOON WITH RAIN/SLEET MIXTURE ALREADY REPORTED OVER NE LA. TEMPERATURES WILL BEGIN TO INCREASE BY MIDNIGHT OVER MOST AREAS WHEN THE AIR COLUMN BEGINS TO MOISTEN AND EVAPORATIVE COOLING IS SHUT DOWN. WE WILL MAINTAIN A CHANCE OF A RAIN/SLEET MIX FOR AREAS ALONG AND N OF THE HIGHWAY 82 CORRIDOR AFTER MIDNIGHT BUT MOST OTHER AREAS WILL SEE PRECIP TURN TO ALL RAIN BY OR SHORTLY AFTER MIDNIGHT. RAIN WILL BE WIDESPREAD OVER THE FORECAST AREA BY SUNRISE THURSDAY AND TEMPERATURES WILL BE ABOVE FREEZING ACROSS THE REGION. THE SURFACE TROUGH LIFTS INTO SRN ZONES BY THURSDAY AFTERNOON... POSITIONING THE ASSOCIATED WARM FRONT IN SE MS BY 18Z. WILL MAINTAIN CHANCE OF THUNDERSTORMS THOSE AREAS TOMORROW AFTERNOON BUT THE TRACK LOOKS TOO FAR S TO SUPPORT ENOUGH INSTABILITY FOR SEVERE CONVECTION. UNDERCUT MOS HIGH TEMPS SLIGHTLY FOR TOMORROW CONSIDERING RAIN SHIELD AND SRN EXTENT OF SURFACE TROUGH. THE BOUNDARY IS EXPECTED TO MOVE THROUGH THE AREA BY THURSDAY EVENING. BEHIND THIS SYSTEM...SFC HIGH PRESSURE OVER THE GREAT PLAINS STATES WILL BEGIN TO MOVE INTO THE AREA FROM THE NORTHWEST. ISENTROPIC ANALYSIS AT THE 285-295K LEVEL AND REMAINING MOISTURE (PWATS AROUND 0.5-0.8 INCH) SHOW A SLIGHT CHANCE FOR SHOWERS FOR FRIDAY...MAINLY IN THE MORNING. WENT AHEAD AND STAYED WITH GUI FOR THU NIGHT INTO SATURDAY MORNING. ANY SHOWERS WILL NOT LAST LONG AS THE ECMWF AND GFS BOTH SHOW HIGH PRESSURE AND NORTHWEST FLOW ALOFT TAKING OVER THE REGION TO START CLEARING OVER THE ARKLAMISS BY SATURDAY AFTERNOON. THE ARCTIC AIRMASS THAT IS MOVING INTO THE REGION WILL COMBINE WITH CLEAR SKIES TO ALLOW LOW TEMPERATURES TO AGAIN DIP DOWN INTO THE 20S FOR THE END OF THE WEEKEND INTO THE BEGINNING OF THE WORK WEEK. THE MAIN CHANGES MADE TO TEMPERATURES WERE TO LOWER JUST A BIT ON FRIDAY NIGHT. SKIES WILL BE CLEARING AS HIGH PRESSURE MOVES IN...AND 925MB TEMPS LOOK TO RANGE FROM 0C TO -8C FOR THIS TIME PERIOD. DECIDED TO JUST BUMP TEMPERATURES DOWN A DEGREE OR TWO FOR THIS TIME PERIOD. FOR THE EXTENDED PORTION OF THE FORECAST (PAST SATURDAY NIGHT)...NO MAJOR CHANGES WERE NECESSARY. THE PREVIOUS LONG TERM DISCUSSION FOLLOWS. /14/ PREVIOUS LONG TERM DISCUSSION...THE DOMINANT HUDSON BAY LOW PATTERN WILL CONTINUE TO BRING SEVERAL COLD EPISODES FOR THE NEXT ONE TO TWO WEEKS IN MOSTLY DRY NORTHWEST FLOW. WITHOUT MUCH TO FOCUS ON PRECIP-WISE...THE PRIMARY FORECAST QUESTIONS CONCERN THE INTENSITY OF COLD AS THE FORECAST AREA WILL EXIST ON THE SRN EDGE OF THE POLAR VORTEX. AT THIS TIME...IT LOOKS AS IF THE CENTER OF COLD AIR ANOMALIES WILL STAY NORTH OF THE REGION...BUT THE NEXT FEW SURGES OF COLD AIR WILL BE SHALLOW AND OF TRUE ARCTIC ORIGINS FROM NEAR THE NORTH POLE. GIVEN RECENT GFS PERFORMANCES WITH SUCH AIRMASSES...HAVE OPTED TO TREND TOWARD COOLER GFS MEAN ENSEMBLE GUIDANCE AND CUT MEX GUIDANCE FROM FRIDAY NIGHT ONWARD (AT LEAST FOR PORTIONS OF THE FORECAST AREA). /EC/ && .AVIATION...WIDESPREAD WINTER PRECIP WILL DEVELOP ACROSS THE REGION THIS EVENING ALONG AND NORTH OF INTERSTATE 20 WITH THE BEST COVERAGE OVER AREAS ALONG AND NORTH OF HIGHWAY 82. HAVE RECEIVED REPORTS OF SLEET OVER NE LA AND TVR THIS AFTERNOON AS INITIAL PRECIP AREA MOVES IN. CLOUD HEIGHTS WILL GRADUALLY DROP AS PRECIP INCREASES IN COVERAGE AND INTENSITY TONIGHT WITH MVFR CONDITIONS MANY LOCATIONS BY MIDNIGHT AND IFR CONDITIONS BY SUNRISE. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 36 45 36 51 / 98 97 25 16 MERIDIAN 35 49 37 53 / 100 96 33 16 VICKSBURG 36 42 37 50 / 96 89 25 17 HATTIESBURG 40 53 39 57 / 100 99 29 16 NATCHEZ 38 46 34 53 / 98 91 22 16 GREENVILLE 32 38 33 43 / 99 95 39 18 GREENWOOD 30 39 34 46 / 100 97 37 18 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR MSZ018-019- 025>034. LA...NONE. AR...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR ARZ074-075. && $$ 03/14 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 940 PM EST TUE JAN 30 2007 .UPDATE... && .SHORT TERM /REST OF TONIGHT/... DRY COLD FRONT THAT WILL BRING THE SECOND ARCTIC SURGE INTO CENTRAL NC IN THE PAST FEW DAYS...IS CURRENTLY LOCATED BETWEEN THE TRIAD AND TRIANGLE. THE WEAK LIFT ASSOCIATED WITH THE FROPA IS PRODUCING A BAND OF BROKEN MID CLOUDS WITH CEILINGS AOA 7.5KFT...WHICH MATCHES UP WELL WITH THE SHALLOW MOIST LAYER BETWEEN 700-800MB SEEN ON THE 00Z/31 GSO RAOB. LIGHT WINDS AND ABSENCE OF CLOUDS HAS ALLOWED TEMPERATURES IN THE NE PIEDMONT AND COASTAL PLAIN TO COOL FASTER THAN OTHER AREAS THIS EVENING...WHILE TEMPERATURES HAVE ACTUALLY ROSE A FEW DEGREES IN THE PAST HOUR OR TWO IN WESTERN AND CENTRAL AREAS WHERE THE CLOUDS AND STRONGER WINDS HAVE PROMOTED MIXING. RUC TIMING OF PUSHING THE COLD FRONT EAST OF THE AREA SHORTLY AFTER 06Z APPEARS REALISTIC...WITH CAA RESULTING IN TEMPERATURES AND DEWPOINTS GRADUALLY FALLING OVERNIGHT. THE STRONGEST CAA WILL OCCUR AFTER DAYBREAK...BEHIND THE VIGOROUS VORT. MAX CURRENTLY DIVING SOUTHEAST INTO THE LOWER OHIO VALLEY. TOUGH CALL ON WHETHER CAA WILL BE STRONG ENOUGH TO RESULT IN UPPER TEENS TO AROUND 20 IN THE NW PIEDMONT AS CURRENT MIN GRIDS INDICATE...AS MIXING WILL BE SUFFICE AS NOT TO ALLOW FURTHER COOLING. WILL RAISE MINS TONIGHT IN THE WEST TO LOWER 20S...OTHERWISE NO OTHER CHANGES EXPECTED. && .PREV DISCUSSION... /ISSUED 230 PM EST TUE JAN 30 2007/ SHORT TERM /TONIGHT THROUGH FRIDAY/... TONIGHT/WEDNESDAY: THE DRY SURFACE COLD FRONT AND ATTENDANT MID LEVEL VORTICITY MAX WILL DROP THROUGH THE AREA LATE TONIGHT... INTRODUCING THE POLAR AIR MASS BENEATH WHICH DEWPOINTS ARE IN THE SINGLE DIGITS TO JUST BELOW ZERO. EXPECT A FEW CLOUDS THIS EVENING THEN MOSTLY CLEAR OVERNIGHT WITH WINDS SWINGING AROUND TO NW. LOWS 19 TO 26. WEDNESDAY SHOULD START OFF WITH PLENTY OF SUNSHINE... THEN MID AND HIGH CLOUDINESS OVER NM AND W TX WILL SWEEP OVER THE AREA... RESULTING IN INCREASED CLOUDS INTO WEDNESDAY EVENING. THICKNESSES INDICATE HIGHS OF 37 TO 43. WEDNESDAY NIGHT THROUGH FRIDAY: ISENTROPIC UPGLIDE BEGINS IN EARNEST LATE WEDNESDAY NIGHT INTO THURSDAY MORNING AS A 40-50 KT 850 MB JET LIFTS OUT OF THE GULF COAST STATES. THE 12Z NAM HAS SPED UP ITS PRECIP ONSET CONSIDERABLY AND IS NOW CLOSER TO THE GFS SOLUTION. HAVE GONE CLOSER TO THE GFS BASED ON ITS BETTER CONSISTENCY. OVERALL PATTERN LOOKS TO BE AN IN SITU DAMMING EVENT WITH A MILLER B CYCLOGENESIS PATTERN. DESPITE THE FACT THAT THE PARENT HIGH CONTAINS AND WILL BE DEPOSITING SOME VERY COLD DRY AIR OVER THE REGION... SINCE IT IS TRANSITORY IN NATURE AND WILL BE SHIFTING OUT INTO THE ATLANTIC... THE LOW LEVEL FEED OF COLD AIR IS UNLIKELY TO BE SUFFICIENTLY LONG LASTING THURSDAY FOR ANY MAJOR ICE ACCUMULATION... AND EXPECT ACCRUAL TO BE SHUT OFF BY LATENT HEAT RELEASE BY THURSDAY AFTERNOON. WILL ISSUE A SPECIAL WEATHER STATEMENT FOR THE WINTRY WEATHER POTENTIAL... BUT HOLD OFF ON SPECIFIC AMOUNTS. GFS PARTIAL THICKNESSES AND FORECAST SOUNDINGS INDICATE AN ONSET OF PRIMARILY SNOW MIXED WITH SLEET IN THE WEST PORTIONS OF CENTRAL NC THURSDAY MORNING... WITH A SMALLER CHANCE OF A WINTRY MIX IN THE EAST. SOUNDINGS START OUT NEAR FREEZING ISOTHERMAL... BUT AT THIS TIME... WITH THE ABSENCE OF STRONG PVA OR JET FORCING... IT LOOKS LIKE PRECIP RATES WILL NOT BE STRONG ENOUGH THURSDAY MORNING TO ALLOW FOR BURSTS OF SNOW THAT COULD LEAD TO NOTABLE ACCUMULATION... ALTHOUGH THIS POTENTIAL CERTAINLY MUST BE WATCHED. THE MID LEVELS THEN WARM RAPIDLY IN THE AFTERNOON... LEADING TO A QUICK TRANSITION TO MOSTLY RAIN EVERYWHERE BY 00Z FRIDAY. HAVE LOWS OF 23-27 WEDNESDAY NIGHT... THEN HAVE A NON-DIURNAL TEMPERATURE TREND... WITH HIGHS THURSDAY 32-39... AND ABOUT 2 DEGREES LOWER FOR LOWS THURSDAY NIGHT. WITH A WEAK SURFACE PATTERN BEHIND THE SPINUP COASTAL LOW AND PLENTY OF RESIDUAL MOISTURE FRIDAY MORNING... EXPECT SLOW CLEARING DURING THE DAY. WILL HAVE HIGHS 45-52... ALTHOUGH IF CLEARING IS MUCH SLOWER FRIDAY... THESE READINGS MAY NEED TO COME DOWN MORE IN LATER FORECASTS. -GIH LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... BROAD L/W TROUGH OVER THE EASTERN U.S. WILL RESULT IN DRY AND CHILLY CONDITIONS ACROSS CENTRAL NC THROUGH THE EXTENDED. MODEL GUIDANCE OFFER VARYING TIMING SOLUTIONS TO THE NEXT SYSTEM IN THE SOUTHERN STREAM. THE ECMWF KEEPS BEST MOISTURE AND LIFT SUPPRESSED WELL SOUTH OF THE AREA. PREVIOUS RUNS OF THE GFS HAD SPREAD MOISTURE WELL NWWD INTO THE COLDER AIR SUN BUT THE RECENT RUN HAS RETRACTED AND HAS DEEPEST MOISTURE S-SE OF AREA. THE CANADIAN PLACES MORE EMPHASIS ON THE NORTHERN STREAM WITH A MILLER A SCENARIO ON SATURDAY WITH LOW TRACKING WEST OF THE MOUNTAINS. ECMWF HAS BEEN CONSISTENT AND WITH THE LATEST GFS TRENDING TOWARD A SIMILAR SCENARIO, PLAN TO KEEP SATURDAY THROUGH TUESDAY PERIOD DRY FOR NOW. GFS ADVECTS BITTERLY COLD AIR INTO REGION DAY 6 AND 7 WITH LOW LEVEL THICKNESSES FALLING INTO THE 1220S BY TUESDAY MORNING. SAW A SIMILAR TREND YESTERDAY FOR MON AND IT HAS SINCE RECOVERED INTO THE 1250S. NEEDLESS...EXPECT MAX TEMPS TO AVERAGE 10-15 DEGREES BELOW NORMAL THROUGH THE PERIOD WITH THE COLDEST WEATHER EXPECTED MON INTO TUE. POTENTIAL FOR MAX TEMPS TO BE COLDER BY DAY6/7 BUT PLENTY OF TIME TO FINE TUNE. -WSS AVIATION /18Z-18Z/... DRY AIR MASS OVER REGION WILL RESULT IN CLEAR SKIES THROUGH 18Z WEDNESDAY. MAY SEE AN INCREASE IN CIRRUS TOWARD 18Z WED AHEAD OF APPROACHING/DEVELOPING SOUTHERN STREAM SYSTEM. REINFORCING SHOT OF COLD DRY AIR WILL OVERSPREAD CENTRAL NC TONIGHT. SURFACE FRONT ASSOCIATED WITH NEW SURGE WILL CROSS REGION BETWEEN 00-05Z. THIS WILL RESULT IN A STEADY NW WIND OVERNIGHT WITH PERIODIC GUSTS AROUND 20KTS. -WSS && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CBL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 809 PM CST TUE JAN 30 2007 .UPDATE... MAIN UPDATE CONCERN IS WITH TEMPERATURES. SFC LOW LOCATED OVER YORKTON SASK AT 00Z AND THIS IS RIGHT ON WITH MODEL LOCATION. USING 21Z AND INCOMING 00Z RUC FOR GUIDANCE SHOWS LOW DROPPING SOUTHEAST TO NEAR THE GRAND FORKS AREA AROUND 12Z. THIS ALSO FITS THE INCOMING 00Z NAM GUIDANCE AS WELL. CANADIAN RADARS AND METARS SHOW LIGHT SNOW NORTHEAST OF SFC LOW CENTER...WITH ANOTHER AREA OF SNOW FURTHER WEST ASSOC WITH VORT MAX AND 500 MB HEIGHT FALL CENTER IN SE ALBERTA/SW SASK. THE VORT OUT WEST WILL DROP INTO ERN MT AND SW ND DURING THE NEXT 12 HOURS AND NOT GREATLY AFFECT OUR AREA. LIGHT SNOW ASSOC WITH SFC LOW WILL MOVE SOUTHEAST AND LIKELY AFFECT NORTHEAST ND AFTER 08Z AND THEN SPREAD THROUGH THE FCST AREA DURING THE PRE-DAWN HOURS THRU MID MORNING ON WEDNESDAY. DID SLIGHT POP TIMING RE-ADJUSTMENTS FOR THIS THINKING. AS FOR TEMPS...SOME DROP SEEN IN THE SOUTHEASTERN FCST AREA WITH WADENA AT ZERO...BUT OTHERWISE SOUTHWEST WIND AND THICKENING HIGH CLOUDS HOLDING TEMPS UP WITH ONLY MINIMAL FALL SINCE 22Z. WITH THICKER CLOUDS TO CONTINUE TO OVERSPREAD THE AREA WOULD EXPECT LITTLE CHANGE IN TEMPS TONIGHT AND MIGHT RISE IN SPOTS. DID ADJUST TEMP GRIDDS TONIGHT THRU 18Z WED FOR THIS THINKING. && .PREV DISCUSSION... /ISSUED 228 PM CST TUE JAN 30 2007/ SHORT TERM... CURRENTLY...ONLY HIGH CLOUDINESS COMBINED WITH SOME MIXING IS ALLOWING DECENT TEMPERATURE RECOVERY THIS AFTERNOON AS A MORE SUBSTANTIAL MID LEVEL DECK MOVES FROM MONTANA/SASKATCHEWAN INTO NW ND AHEAD OF VORT/SHORT WAVE IN CENTRAL SASKATCHEWAN. WITH RESPECT TO GUIDANCE...WILL TEND TOWARDS THE GFS AND ITS PROGRESSIVE MOVEMENT OF SYSTEMS AND ITS RECENT CONSISTENCY. TONIGHT/WEDNESDAY...FIRST OF TWO CLIPPERS DESCENDS THIS EVENING INTO NORTHERN FORECAST AREA DURING THE OVERNIGHT. FCST SOUNDINGS INDICATE ENOUGH MOISTURE TO GO WITH AT LEAST CHANCE POPS PROGRESSING FROM NORTH TO SOUTH. WARM ADVECTION AHEAD OF SYSTEM ALONG WITH THICKENING CLOUD AND SW WIND MAY YIELD NON- DIURNAL TEMP TREND OVERNIGHT...THIS CAN BE REFINED BY THE EVENING CREW MEMBERS. DON`T SEE MUCH COLD PUNCH BEHIND THIS FIRST SYSTEM SO MINIMAL PROBLEMS WITH BLOWING/DRIFTING ARE ANTICIPATED AT THIS TIME. HIGH PRESSURE BRIEFLY NUDGES IN BEHIND DEPARTING CLIPPER LATER WEDNESDAY...WHICH WILL BE SHORT LIVED AS THE MORE POTENT SYSTEM LURKING TO THE NORTH TAKES AIM ON THE FORECAST AREA FOR THURSDAY. THURSDAY/FRIDAY...NEXT SYSTEM MORE LOADED IN TERMS OF LIFT...GRADIENT AND DEEP LAYERED MOISTURE. THESE FACTORS COMPUTE TO LIKELY POPS THURSDAY AFTERNOON FOLLOWED BY ROBUST SURGE OF COLD AIR ADVECTION THURSDAY NIGHT. NORTHERLY WINDS WITH SOLID LINKAGE (ALBEIT PERHAPS NOT AS STRONG AS PRIOR RUNS) WILL PRODUCE VENTURI EFFECT FOR THE VALLEY. ALL IN ALL THIS INCREASES THE POTENTIAL FOR A BLOWING SNOW/VERY LOW VISIBILITY EVENT PRIMARILY OVER OPEN COUNTRY...H925 LEVEL WINDS CLOSE TO 30 KTS LIKELY TO TRANSLATE DOWN TO 20-25 KTS WITH HIGHER GUSTS AT SURFACE...WITH AREA OF MAXIMUM PRESSURE RISES LOOKING NOW TO BE OVER CENTRAL ND. SATURATED COLUMN TO AT LEAST 600 MB SHOULD PERSIST ON FRIDAY...WINDS DIMINISH...BUT EVEN WITH LACK OF OTHER PARAMETERS...MOISTURE WILL BE SUFFICIENT TO KEEP SNOW SHOWER ACTIVITY ALIVE. LONG TERM (SAT THROUGH TUE)...LONG RANGE MODELS REMAIN IN PRETTY GOOD AGREEMENT FOR EXTENDED FORECAST. 500MB TROF AND SURFACE LOW START MOVING E OF THE AREA ON SAT...KEEPING A NW FLOW OVER THE REGION THROUGH THE WEEKEND. VERY COLD TEMPERATURES WITH WIND WILL CONTINUE ON SAT...UNTIL THE SURFACE HIGH PRESSURE SYSTEM BUILDS IN FOR SUN. THEN...THE COLD TEMPERATURES REMAIN...BUT WITH LESS WIND FOR SUN AND SUN NIGHT. ON MON...THE SURFACE HIGH PRESSURE STARTS MOVING E AND S-SE RETURN FLOW SETS UP...KEEPING THE COLD AIR MASS OVER THE REGION FOR ONE MORE DAY. AS FAR AS TEMPERATURES...KEPT MUCH BELOW NORMAL THROUGH THE EXTENDED FORECAST. FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. $$ RIDDLE/ nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 954 PM CST WED JAN 31 2007 .UPDATE... A FEW AREAS OF LIGHT FREEZING DRIZZLE/RAIN CONTINUE OVER PORTIONS OF OKLAHOMA THIS EVENING. SECOND ROUND ORGANIZING OVER WEST TEXAS THIS EVENING AND APPEARS TO BE GOING AS PLANNED. LATEST NAM RUN CONTINUES TO INDICATE FAIRLY PRONOUNCED BAND OF FRONTOGENETICAL FORCING NEAR THE I-40 CORRIDOR TOMORROW MORNING...WHICH RAISES A CONCERN FOR THE POSSIBILITY OF 4 TO 6 INCH TOTALS. LAST RUN OF THE SREF AND 00Z GFS HAVE BACKED OFF...GFS WAY OFF...FROM PREVIOUS POTENTIAL. GIVEN THE LATEST GUIDANCE...AND THE FACT THAT WE ARE ALREADY MENTIONING BANDED TOTALS OF 4+...WILL HOLD OFF ON A HEAVY SNOW WARNING. MIDSHIFT WILL MONITOR RADAR/SATELLITE TRENDS AND LATEST GUIDANCE AND ISSUE IF NECESSARY. ALSO RAISED POPS CONSIDERABLY ACROSS MAINLY NORTHWEST THIRD OF OKLAHOMA THURSDAY NIGHT AND FRIDAY AS NORTHWEST FLOW SYSTEM MOVES IN. THESE SYSTEM CAN BE VERY EFFICIENT...ESPECIALLY GIVEN ACCOMPANYING LOW-MID LEVEL BAROCLINIC ZONE. && .PREV DISCUSSION... /ISSUED 406 PM CST WED JAN 31 2007/ DISCUSSION...SNOW THIS MORNING WAS MOST CONCENTRATED OVER NORTHERN OKLAHOMA...WITH 1 TO 2 INCHES. LIGHT SNOW AND SLEET ELSEWHERE WAS MORE INTERMITTENT...BUT THE FREEZING DRIZZLE WHICH FOLLOWED HAS GREATLY IMPACTED TRAVEL. THIS OCCURRED AS WESTERLY MID LEVEL WINDS AND SUBSIDENCE REMOVED MOISTURE FROM THE ICE CRYSTAL GROWTH ZONE...WHILE MOIST ISENTROPIC UPGLIDE CONTINUED AT LOWER LEVELS. THERE IS A DISTINCT BACK EDGE TO THE UPGLIDE PUSHING THROUGH CENTRAL AND SOUTHERN OKLAHOMA THIS AFTERNOON. A COLD FRONT WILL ALSO MOVE INTO WESTERN OKLAHOMA AND NORTH TEXAS THIS EVENING...SO LOW LEVEL DOWNGLIDE WILL BE THE RULE OVERNIGHT...HOPEFULLY PREVENTING ANY MORE FREEZING DRIZZLE. MEANWHILE...WE STILL APPEAR ON TRACK TO RECEIVE A SWATH OF SNOW LATE TONIGHT AND THURSDAY MORNING. ALTHOUGH NOT ESPECIALLY HEAVY...ACCUMULATIONS WILL OCCUR EITHER SIDE OF THE THURSDAY MORNING COMMUTE...AGAIN IMPACTING TRAVEL. WE ARE ALSO CONCERNED THAT FREEZING RAIN WILL IMPACT PARTS OF SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS LATER TONIGHT. ORIGINALLY...THIS WAS EXPECTED TO BE RAIN...BUT TEMPERATURES ARE A COUPLE OF DEGREES COOLER THAN EXPECTED THIS AFTERNOON. DEWPOINTS ARE STILL WELL BELOW FREEZING...AND SURFACE WINDS WILL SWING AROUND TO EAST AND NORTHEAST OVERNIGHT. THEREFORE...WILL ISSUE A WINTER WEATHER ADVISORY FOR A ROW OF COUNTIES SOUTH OF THE SNOW ADVISORY. REALLY DIFFICULT TO DRAW THE FREEZING LINE EVEN 12 HOURS AHEAD OF TIME...BUT OUR ADVISORY WILL BE BASED LARGELY ON THE 18Z RUC SURFACE TEMPERATURES AND SHORT RANGE ENSEMBLE 850 MB TEMPS. WHILE MOST AREAS WILL SEE ADDITIONAL PRECIP...THERE IS STILL BELOW AVERAGE CONFIDENCE IN WHERE TO PLACE THE HIGHEST AMOUNTS. THE NAM HAS LATCHED ONTO THE LOW LEVEL FRONTOGENESIS NEAR THE RED RIVER...WHILE THE GFS PAINTS MORE SNOW ALONG THE MID LEVEL FRONT FROM WESTERN INTO CENTRAL OKLAHOMA. BOTH AREAS ARE LIKELY TO SEE LIGHT ACCUMULATIONS...BUT THE MORE CONSISTENT SIGNAL...AND LESS CHANCE FOR MELTING IS WITH THE ACTIVITY FORECAST TO SURROUND INTERSTATE 40 BOTH NORTH AND SOUTH. WILL CONTINUE WITH OUR FORECAST OF 1 TO 3 INCHES OF SNOW OVER A BROAD AREA...BUT MESOSCALE BANDING AND/OR SOME WEAK CONVECTION MAY LEAD TO HIGHER TOTALS IN SMALL AREAS. WHATEVER DOES FALL WILL LIKELY REMAIN ON THE GROUND THROUGH THE WEEKEND...AS THURSDAY AFTERNOON AND NIGHT REMAIN CLOUDY...AND AN ARCTIC FRONT ARRIVES FRIDAY. LOW LEVEL MOISTURE WILL ALSO LINGER IN THE AREA LATE THURSDAY...AND LIGHT SNOW OR FREEZING RAIN SEEMS A POSSIBILITY. WILL INCREASE TO CHANCE POPS ALONG THE STALLED LOW LEVEL FRONT NEAR THE RED RIVER...AND ALONG THE APPROACHING ARCTIC FRONT IN THE NORTHWEST. EXPECT THIS PRECIP WOULD BE LIGHT...BUT AS WE HAVE SEEN...IT DOES NOT TAKE MUCH TO CAUSE PROBLEMS. IN THE EXTENDED...THE LONGWAVE PATTERN SEEMS UNLIKELY TO BUDGE...WITH WHAT LOOKS LIKE AN OMEGA BLOCK ON AN UNUSUALLY LARGE SCALE...FROM THE PACIFIC ACROSS NORTH AMERICA. THE RIDGE IN THE BLOCK MAY TEND TO MOVE EAST BUT ALSO BE BATTED BACK BY LOW LEVEL COLD AIR INTRUSIONS OUT OF CENTRAL CANADA. SO WILL CONTINUE A COOL FORECAST...BUT WITH A VERY SLOW WARMING TREND. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 25 32 20 26 / 90 80 40 40 HOBART OK 26 31 21 28 / 90 60 40 40 WICHITA FALLS TX 32 36 26 32 / 80 50 30 30 GAGE OK 20 29 16 21 / 60 20 60 60 PONCA CITY OK 20 29 16 22 / 60 50 40 40 DURANT OK 32 38 28 35 / 80 80 20 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ004>044. WINTER WEATHER ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ045>048- 051-052. TX...SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR TXZ083. WINTER WEATHER ADVISORY UNTIL 12 PM CST THURSDAY FOR TXZ084>086. && $$ 11/25 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 406 PM CST WED JAN 31 2007 .DISCUSSION...SNOW THIS MORNING WAS MOST CONCENTRATED OVER NORTHERN OKLAHOMA...WITH 1 TO 2 INCHES. LIGHT SNOW AND SLEET ELSEWHERE WAS MORE INTERMITTENT...BUT THE FREEZING DRIZZLE WHICH FOLLOWED HAS GREATLY IMPACTED TRAVEL. THIS OCCURRED AS WESTERLY MID LEVEL WINDS AND SUBSIDENCE REMOVED MOISTURE FROM THE ICE CRYSTAL GROWTH ZONE...WHILE MOIST ISENTROPIC UPGLIDE CONTINUED AT LOWER LEVELS. THERE IS A DISTINCT BACK EDGE TO THE UPGLIDE PUSHING THROUGH CENTRAL AND SOUTHERN OKLAHOMA THIS AFTERNOON. A COLD FRONT WILL ALSO MOVE INTO WESTERN OKLAHOMA AND NORTH TEXAS THIS EVENING...SO LOW LEVEL DOWNGLIDE WILL BE THE RULE OVERNIGHT...HOPEFULLY PREVENTING ANY MORE FREEZING DRIZZLE. MEANWHILE...WE STILL APPEAR ON TRACK TO RECEIVE A SWATH OF SNOW LATE TONIGHT AND THURSDAY MORNING. ALTHOUGH NOT ESPECIALLY HEAVY...ACCUMULATIONS WILL OCCUR EITHER SIDE OF THE THURSDAY MORNING COMMUTE...AGAIN IMPACTING TRAVEL. WE ARE ALSO CONCERNED THAT FREEZING RAIN WILL IMPACT PARTS OF SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS LATER TONIGHT. ORIGINALLY...THIS WAS EXPECTED TO BE RAIN...BUT TEMPERATURES ARE A COUPLE OF DEGREES COOLER THAN EXPECTED THIS AFTERNOON. DEWPOINTS ARE STILL WELL BELOW FREEZING...AND SURFACE WINDS WILL SWING AROUND TO EAST AND NORTHEAST OVERNIGHT. THEREFORE...WILL ISSUE A WINTER WEATHER ADVISORY FOR A ROW OF COUNTIES SOUTH OF THE SNOW ADVISORY. REALLY DIFFICULT TO DRAW THE FREEZING LINE EVEN 12 HOURS AHEAD OF TIME...BUT OUR ADVISORY WILL BE BASED LARGELY ON THE 18Z RUC SURFACE TEMPERATURES AND SHORT RANGE ENSEMBLE 850 MB TEMPS. WHILE MOST AREAS WILL SEE ADDITIONAL PRECIP...THERE IS STILL BELOW AVERAGE CONFIDENCE IN WHERE TO PLACE THE HIGHEST AMOUNTS. THE NAM HAS LATCHED ONTO THE LOW LEVEL FRONTOGENESIS NEAR THE RED RIVER...WHILE THE GFS PAINTS MORE SNOW ALONG THE MID LEVEL FRONT FROM WESTERN INTO CENTRAL OKLAHOMA. BOTH AREAS ARE LIKELY TO SEE LIGHT ACCUMULATIONS...BUT THE MORE CONSISTENT SIGNAL...AND LESS CHANCE FOR MELTING IS WITH THE ACTIVITY FORECAST TO SURROUND INTERSTATE 40 BOTH NORTH AND SOUTH. WILL CONTINUE WITH OUR FORECAST OF 1 TO 3 INCHES OF SNOW OVER A BROAD AREA...BUT MESOSCALE BANDING AND/OR SOME WEAK CONVECTION MAY LEAD TO HIGHER TOTALS IN SMALL AREAS. WHATEVER DOES FALL WILL LIKELY REMAIN ON THE GROUND THROUGH THE WEEKEND...AS THURSDAY AFTERNOON AND NIGHT REMAIN CLOUDY...AND AN ARCTIC FRONT ARRIVES FRIDAY. LOW LEVEL MOISTURE WILL ALSO LINGER IN THE AREA LATE THURSDAY...AND LIGHT SNOW OR FREEZING RAIN SEEMS A POSSIBILITY. WILL INCREASE TO CHANCE POPS ALONG THE STALLED LOW LEVEL FRONT NEAR THE RED RIVER...AND ALONG THE APPROACHING ARCTIC FRONT IN THE NORTHWEST. EXPECT THIS PRECIP WOULD BE LIGHT...BUT AS WE HAVE SEEN...IT DOES NOT TAKE MUCH TO CAUSE PROBLEMS. IN THE EXTENDED...THE LONGWAVE PATTERN SEEMS UNLIKELY TO BUDGE...WITH WHAT LOOKS LIKE AN OMEGA BLOCK ON AN UNUSUALLY LARGE SCALE...FROM THE PACIFIC ACROSS NORTH AMERICA. THE RIDGE IN THE BLOCK MAY TEND TO MOVE EAST BUT ALSO BE BATTED BACK BY LOW LEVEL COLD AIR INTRUSIONS OUT OF CENTRAL CANADA. SO WILL CONTINUE A COOL FORECAST...BUT WITH A VERY SLOW WARMING TREND. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 27 32 20 26 / 90 70 20 30 HOBART OK 27 31 21 28 / 90 40 30 30 WICHITA FALLS TX 32 36 26 32 / 80 40 30 30 GAGE OK 20 29 16 21 / 60 20 30 30 PONCA CITY OK 21 29 16 22 / 60 50 20 20 DURANT OK 32 38 28 35 / 80 70 30 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR OKZ014>019-021>032-040-042. SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ014>019-021>044. SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ004>013-020. WINTER WEATHER ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ045>048- 051-052. TX...SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR TXZ083. WINTER WEATHER ADVISORY UNTIL 12 PM CST THURSDAY FOR TXZ084>086. && $$ BURKE/SIX ok AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE STATE COLLEGE PA 107 AM EST WED JAN 31 2007 .AVIATION /06Z-06Z/... IR SAT IMAGERY SHOWING SOME CONSIDERABLE BINOVC SC DECK...WITH SOME SITES SCOURING OUT TO SKC-SCT. UPSLOPE/LAKE SNOW SHOWERS WILL KEEP IFR/MVFR CONDS ACROSS THE WESTERN TAFS /KBFD- KJST/ WITH DOWNSLOPING WRLY COMPNT TO THE LLVL WND FIELD AIDING IN VFR CONDS ELSEWHERE. HOWEVER...STILL CANNOT RULE OF A BRIEF REDUCTION TO MVFR AT KUNV/KIPT/KAOO THRU THE EARLY MORNING HOURS WITH OCNL -SHSN. WEST TO WNW SFC WNDS 10-15KTS WITH HIGHER GUSTS...ESP AT KJST AND KMDT. HI PRES CURRENTLY OVR THE MID MS VLY WILL MOVE EWD INTO THE SRN MID ATLANTIC STATES...EFFECTIVELY LOWERING INVERSION HGTS AND SHUTTING DOWN THE LAKE SNOWS - ALLOWING KBFD/KJST TO IMPROVE BY LATE MORNING OR EARLY AFT. && .PREV DISCUSSION... /ISSUED 1223 AM EST WED JAN 31 2007/ SHORT TERM /REST OF TONIGHT/... JUST A QUICK UPDATE TO DROP THE ADVISORY FOR THE NRN MTS/POCONOS. ONLY A FEW FLURRIES WILL BE LEFT THERE...AS LOW IS WELL TO THE EAST AND INVERSION LOWERING SFC PRESSURES RISING. WILL TWEAK JUST THE FIRST PD WORDING FOR NOW. ALSO RE-ISSUED THE WSW FOR NOW...WITH LIGHT SNOW CONTINUING AS THE UPSLOPE AND CROSS-LAKE FETCH CONTINUES. SO WILL JUST CONTINUE THEM FOR NOW. PREV DISCUSSION... /ISSUED 1012 PM EST TUE JAN 30 2007/ SHORT TERM /THROUGH TUESDAY NIGHT/... WILL SEND OUT A QUICK...LATE EVENING ZONE UPDATE TO FRESHEN UP THE WORDING FOR SNOW SHOWERS ACROSS THE REGION. ARCTIC FRONT HAS PUSHED EAST OF THE SUSI VALLEY...TAKING THE HEAVY SQUALLS WITH IT. WEAKENING MID LEVEL DEFORMATION SNOWS ACROSS THE NCENT MTNS WILL BRING ANOTHER INCH OR TWO TO SOME LOCATIONS OVER THE NEXT FEW HOURS WITHIN THE SNOW ADVISORY...WHICH SET TO EXPIRE AT MIDNIGHT EST. PERSISTENT LAKE EFFECT/OROGRAPHIC SNOWS ACROSS THE NW MTNS AND LAUREL HIGHLANDS RESPECTIVELY WILL CONTINUE TO ACCUMULATE A FEW MORE INCHES OVERNIGHT...SO NO CHANGES TO THE LAKE EFFECT/SNOW ADVISORIES FOR THOSE AREAS. ELSEWHERE...EXPECT FLURRIES AND A BRIEF HEAVIER SNOW SHOWER OVERNIGHT AS THE PRIMARY 700-500 HPA THERMAL TROUGH MOVES SE FROM THE GLAKES. ACCUMULATIONS WILL BE LESS THAN AN INCH ACROSS THE CENTRAL RIDGE AND VALLEY REGION. OVC LAYER WILL BREAK UP AFTER MIDNIGHT ACROSS THE LOWER SUSQ VALLEY AS DRIER DEWPOINTS IN THE UPPER SINGLE DIGITS ADVECT EAST VIA A DOWNSLOPE LLVL FLOW. TRIMMED HOURLY AND MIN TEMPS OVERNIGHT BY 2-4 DEG F IN MANY LOCATIONS. PREV DISCUSSION... /ISSUED 728 PM EST TUE JAN 30 2007/ SHORT TERM /THROUGH TONIGHT/... AREA OF INSTABILITY WITH TOTAL TOTALS NEAR 50 CROSSING THE SUSQ VALLEY...ALONG WITH A RATHER STRONG...ALBEIT COMPACT UPPER SHORT WAVE MOVE EAST OVER THE NCENT MTNS WILL BRING NUMEROUS SNOW SHOWERS AND LOCALLY HEAVY SNOW SQUALLS EARLY TONIGHT. ISSUED A SNOW ADVISORY ACROSS THE NCENT MTNS THROUGH MIDNIGHT WHERE A MESO-B MID LVL DEFORMATION ZONE AND CORRESPONDING EAST/WEST BELT OF ENHANCED 850-700 HPA OMEGA WILL LEAD TO SEVERAL INCHES OF NEW SNOW. SNOW SHOWERS AND SQUALLS WILL DIMINISH TO SCATTERED FLURRIES ACROSS THE CENTRAL VALLEYS AND SUSQ RIVER VALLEY LATE THIS EVENING. PREV DISCUSSION... /ISSUED 325 PM EST TUE JAN 30 2007/ SHORT TERM /TONIGHT THROUGH WEDNESDAY/... MESO ANAL SHOWS SFC LOW JUST WEST OF BFD AT 18Z...WITH THE COLD FRONT MOVING THRU SWRN PA. RUC SHOWS A POCKET OF RELATIVELY UNSTABLE AIR...LOW-MID LEVEL LAPSE RATES IN EXCESS OF 6C/KM AND T-TOTALS TOPPING 50...HELPING TRIGGER THE CURRENT SNOW SHOWERS AND SQUALLS MOVING ACROSS THE AREA. THE BEST FORCING/INSTABILITY STARTS TO WANE AFTER ABOUT 21Z ACCORDING TO SHORT TERM GUIDANCE...WITH THE FRONT EXPECTED TO CLEAR MY EASTERN ZONES BY 00Z. AFTER THE FROPA...WE WILL TRANSITION INTO A MORE TYPICAL NW FLOW REGIME WITH LAKE EFFECT AND OROGRAPHICALLY FORCED SNOWS IN THE WEST...AND ACTIVITY TAPERING OFF TO JUST SCATTERED SNOW SHOWERS AND FLURRIES THE FURTHER DOWNWIND OF THE LAKES AND LAURELS ONE GETS. ONLY CONCERN IS A HINT IN THE MODELS THAT THE UPPER-AIR PORTION OF THE OCCLUDED FRONT HANGS TOUGH FOR A TIME INTO NW PA...ENHANCING THE CONVERGENCE THERE INTO THE EVENING. THIS SHOWS UP AS A WELL DEFINED THERMAL RIDGE UP THRU ABOUT 850MB IN ALL THE SHORT RANGE GUIDANCE. THEY SHIFT THIS EAST OF THE AREA AFTER 03Z. WEDNESDAY WILL SEE CONDITIONS IMPROVING AS INVERSION HEIGHTS LOWER THROUGHOUT THE DAY. THE BEST CHANCE OF LINGERING SNOW WILL BE OVER WESTERN HIGH TERRAIN. ELSEWHERE WE SHUD SEE LITTLE MORE THAN FLURRIES. LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... UPPER TROFFING OVER EASTERN NORTH AMERICA LOOKS TO DOMINATE THE LONG TERM PERIOD. THIS WILL LEAD TO NEAR TO BELOW NORMAL TEMPERATURES EARLY IN THE PERIOD AND POSSIBLY SIGNIFICANTLY BELOW NORMAL TEMPERATURES LATE IN THE PERIOD. MOST OF THE PERIOD LOOKS DRY...BUT TWO OPPORTUNITIES FOR PCPN STAND OUT. A WEATHER SYSTEM THAT HAS BEEN ADVERTISED FOR SEVERAL DAYS TO AFFECT THE REGION LATE THURSDAY INTO FRIDAY CONTINUES TO LOOK COMPLEX...WITH VARYING RUN TO RUN MODEL SOLUTIONS. A SOUTHERN STREAM TROF IS FORECAST TO INDUCE CYCLOGENESIS OVER THE SOUTHEAST U.S. THURSDAY NIGHT WITH A NORTHERN STREAM TROF FORECAST TO SWING THROUGH THE REGION LATER FRIDAY. MUCH YET DEPENDS ON THE TRACK OF THE COASTAL LOW AND ANY PHASING THAT MAY TAKE PLACE BETWEEN THE TWO STREAMS. AT THIS TIME...THERE IS A HIGH PROBABILITY OF MEASURABLE ACROSS ALL OF THE CWA...WITH POTENTIAL FOR A SEVERAL INCH SNOWFALL ACROSS THE REGION...EVEN THE LOWER SUSQUEHANNA VALLEY...WHERE SNOWFALL SO FAR THIS SEASON IS LESS THAN AN INCH TOTAL. A PRONOUNCED ARCTIC TROF IS FORECAST TO MOVE THROUGH THE FORECAST AREA ON MONDAY...POTENTIALLY BRINGING IN THE COLDEST AIR YET THIS WINTER. AVIATION /20Z-18Z/... THE AFTERNOON`S WIDESPREAD IFR CAUSED BY THE SHORTWAVE AND SNOW SHOWERS SHUD BEGIN TO IMPROVE IN MOST AREAS THIS EVENING AS THE UPPER TROF MOVES EAST OF THE REGION AND A WEST-NORTHWEST FLOW DEVELOPS. LIKE A BROKEN RECORD THOUGH...JST/BFD WILL NOT SHARE IN THE IMPROVEMENT AS UPSLOPE AND PROXIMITY TO LAKE ERIE CONSPIRE TO KEEP BOTH TERMINALS MAINLY DOWN BELOW 3000/3 WITH FREQUENT SNOW SHOWERS BRINGING EVEN LOWER CONDITIONS. WILL PROB SEE AOO/UNV/IPT IMPROVE TO MVFR CEILINGS AND MOSTLY UNLIMITED VIS WITH ONLY OCNL SNOW SHOWERS BRINGING BRIEFLY REDUCED VIS AFTER 00Z...WITH VFR DEVELOPING SLOWLY LATER TONIGHT INTO EARLY WED MORNING. STILL A QUESTION AS TO WHETHER THE FAR SERN TERMINALS WILL SEE MUCH INCLEMENT WX AT ALL AS THE SYSTEM IS ALREADY MOISTURE STARVED AND DOWN-SLOPING FLOW WILL ONLY HELP IN MAKING MUCH OF THE SNOW SHOWER ACTIVITY DRY UP BEFORE IT MAKES IT INTO THE LOWER SUSQ VALLEY. THINK THERE IS A CHC OF SNOW SHOWERS AND BRIEFLY LOWER CONDITIONS THRU THE EVENING...BUT AFTER THAT CIG/VIS SHUD NOT POSE MUCH OF A CHALLENGE THERE. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ004-005-010. SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ024-033. && $$ AVIATION...STEINBUGL pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1223 AM EST WED JAN 31 2007 .SHORT TERM /REST OF TONIGHT/... JUST A QUICK UPDATE TO DROP THE ADVISORY FOR THE NRN MTS/POCONOS. ONLY A FEW FLURRIES WILL BE LEFT THERE...AS LOW IS WELL TO THE EAST AND INVERSION LOWERING SFC PRESSURES RISING. WILL TWEAK JUST THE FIRST PD WORDING FOR NOW. ALSO RE-ISSUED THE WSW FOR NOW...WITH LIGHT SNOW CONTINUING AS THE UPSLOPE AND CROSS-LAKE FETCH CONTINUES. SO WILL JUST CONTINUE THEM FOR NOW. && .PREV DISCUSSION... /ISSUED 1012 PM EST TUE JAN 30 2007/ SHORT TERM /THROUGH TUESDAY NIGHT/... WILL SEND OUT A QUICK...LATE EVENING ZONE UPDATE TO FRESHEN UP THE WORDING FOR SNOW SHOWERS ACROSS THE REGION. ARCTIC FRONT HAS PUSHED EAST OF THE SUSI VALLEY...TAKING THE HEAVY SQUALLS WITH IT. WEAKENING MID LEVEL DEFORMATION SNOWS ACROSS THE NCENT MTNS WILL BRING ANOTHER INCH OR TWO TO SOME LOCATIONS OVER THE NEXT FEW HOURS WITHIN THE SNOW ADVISORY...WHICH SET TO EXPIRE AT MIDNIGHT EST. PERSISTENT LAKE EFFECT/OROGRAPHIC SNOWS ACROSS THE NW MTNS AND LAUREL HIGHLANDS RESPECTIVELY WILL CONTINUE TO ACCUMULATE A FEW MORE INCHES OVERNIGHT...SO NO CHANGES TO THE LAKE EFFECT/SNOW ADVISORIES FOR THOSE AREAS. ELSEWHERE...EXPECT FLURRIES AND A BRIEF HEAVIER SNOW SHOWER OVERNIGHT AS THE PRIMARY 700-500 HPA THERMAL TROUGH MOVES SE FROM THE GLAKES. ACCUMULATIONS WILL BE LESS THAN AN INCH ACROSS THE CENTRAL RIDGE AND VALLEY REGION. OVC LAYER WILL BREAK UP AFTER MIDNIGHT ACROSS THE LOWER SUSQ VALLEY AS DRIER DEWPOINTS IN THE UPPER SINGLE DIGITS ADVECT EAST VIA A DOWNSLOPE LLVL FLOW. TRIMMED HOURLY AND MIN TEMPS OVERNIGHT BY 2-4 DEG F IN MANY LOCATIONS. PREV DISCUSSION... /ISSUED 728 PM EST TUE JAN 30 2007/ SHORT TERM /THROUGH TONIGHT/... AREA OF INSTABILITY WITH TOTAL TOTALS NEAR 50 CROSSING THE SUSQ VALLEY...ALONG WITH A RATHER STRONG...ALBEIT COMPACT UPPER SHORT WAVE MOVE EAST OVER THE NCENT MTNS WILL BRING NUMEROUS SNOW SHOWERS AND LOCALLY HEAVY SNOW SQUALLS EARLY TONIGHT. ISSUED A SNOW ADVISORY ACROSS THE NCENT MTNS THROUGH MIDNIGHT WHERE A MESO-B MID LVL DEFORMATION ZONE AND CORRESPONDING EAST/WEST BELT OF ENHANCED 850-700 HPA OMEGA WILL LEAD TO SEVERAL INCHES OF NEW SNOW. SNOW SHOWERS AND SQUALLS WILL DIMINISH TO SCATTERED FLURRIES ACROSS THE CENTRAL VALLEYS AND SUSQ RIVER VALLEY LATE THIS EVENING. PREV DISCUSSION... /ISSUED 325 PM EST TUE JAN 30 2007/ SHORT TERM /TONIGHT THROUGH WEDNESDAY/... MESO ANAL SHOWS SFC LOW JUST WEST OF BFD AT 18Z...WITH THE COLD FRONT MOVING THRU SWRN PA. RUC SHOWS A POCKET OF RELATIVELY UNSTABLE AIR...LOW-MID LEVEL LAPSE RATES IN EXCESS OF 6C/KM AND T-TOTALS TOPPING 50...HELPING TRIGGER THE CURRENT SNOW SHOWERS AND SQUALLS MOVING ACROSS THE AREA. THE BEST FORCING/INSTABILITY STARTS TO WANE AFTER ABOUT 21Z ACCORDING TO SHORT TERM GUIDANCE...WITH THE FRONT EXPECTED TO CLEAR MY EASTERN ZONES BY 00Z. AFTER THE FROPA...WE WILL TRANSITION INTO A MORE TYPICAL NW FLOW REGIME WITH LAKE EFFECT AND OROGRAPHICALLY FORCED SNOWS IN THE WEST...AND ACTIVITY TAPERING OFF TO JUST SCATTERED SNOW SHOWERS AND FLURRIES THE FURTHER DOWNWIND OF THE LAKES AND LAURELS ONE GETS. ONLY CONCERN IS A HINT IN THE MODELS THAT THE UPPER-AIR PORTION OF THE OCCLUDED FRONT HANGS TOUGH FOR A TIME INTO NW PA...ENHANCING THE CONVERGENCE THERE INTO THE EVENING. THIS SHOWS UP AS A WELL DEFINED THERMAL RIDGE UP THRU ABOUT 850MB IN ALL THE SHORT RANGE GUIDANCE. THEY SHIFT THIS EAST OF THE AREA AFTER 03Z. WEDNESDAY WILL SEE CONDITIONS IMPROVING AS INVERSION HEIGHTS LOWER THROUGHOUT THE DAY. THE BEST CHANCE OF LINGERING SNOW WILL BE OVER WESTERN HIGH TERRAIN. ELSEWHERE WE SHUD SEE LITTLE MORE THAN FLURRIES. LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... UPPER TROFFING OVER EASTERN NORTH AMERICA LOOKS TO DOMINATE THE LONG TERM PERIOD. THIS WILL LEAD TO NEAR TO BELOW NORMAL TEMPERATURES EARLY IN THE PERIOD AND POSSIBLY SIGNIFICANTLY BELOW NORMAL TEMPERATURES LATE IN THE PERIOD. MOST OF THE PERIOD LOOKS DRY...BUT TWO OPPORTUNITIES FOR PCPN STAND OUT. A WEATHER SYSTEM THAT HAS BEEN ADVERTISED FOR SEVERAL DAYS TO AFFECT THE REGION LATE THURSDAY INTO FRIDAY CONTINUES TO LOOK COMPLEX...WITH VARYING RUN TO RUN MODEL SOLUTIONS. A SOUTHERN STREAM TROF IS FORECAST TO INDUCE CYCLOGENESIS OVER THE SOUTHEAST U.S. THURSDAY NIGHT WITH A NORTHERN STREAM TROF FORECAST TO SWING THROUGH THE REGION LATER FRIDAY. MUCH YET DEPENDS ON THE TRACK OF THE COASTAL LOW AND ANY PHASING THAT MAY TAKE PLACE BETWEEN THE TWO STREAMS. AT THIS TIME...THERE IS A HIGH PROBABILITY OF MEASURABLE ACROSS ALL OF THE CWA...WITH POTENTIAL FOR A SEVERAL INCH SNOWFALL ACROSS THE REGION...EVEN THE LOWER SUSQUEHANNA VALLEY...WHERE SNOWFALL SO FAR THIS SEASON IS LESS THAN AN INCH TOTAL. A PRONOUNCED ARCTIC TROF IS FORECAST TO MOVE THROUGH THE FORECAST AREA ON MONDAY...POTENTIALLY BRINGING IN THE COLDEST AIR YET THIS WINTER. AVIATION /20Z-18Z/... THE AFTERNOON`S WIDESPREAD IFR CAUSED BY THE SHORTWAVE AND SNOW SHOWERS SHUD BEGIN TO IMPROVE IN MOST AREAS THIS EVENING AS THE UPPER TROF MOVES EAST OF THE REGION AND A WEST-NORTHWEST FLOW DEVELOPS. LIKE A BROKEN RECORD THOUGH...JST/BFD WILL NOT SHARE IN THE IMPROVEMENT AS UPSLOPE AND PROXIMITY TO LAKE ERIE CONSPIRE TO KEEP BOTH TERMINALS MAINLY DOWN BELOW 3000/3 WITH FREQUENT SNOW SHOWERS BRINGING EVEN LOWER CONDITIONS. WILL PROB SEE AOO/UNV/IPT IMPROVE TO MVFR CEILINGS AND MOSTLY UNLIMITED VIS WITH ONLY OCNL SNOW SHOWERS BRINGING BRIEFLY REDUCED VIS AFTER 00Z...WITH VFR DEVELOPING SLOWLY LATER TONIGHT INTO EARLY WED MORNING. STILL A QUESTION AS TO WHETHER THE FAR SERN TERMINALS WILL SEE MUCH INCLEMENT WX AT ALL AS THE SYSTEM IS ALREADY MOISTURE STARVED AND DOWN-SLOPING FLOW WILL ONLY HELP IN MAKING MUCH OF THE SNOW SHOWER ACTIVITY DRY UP BEFORE IT MAKES IT INTO THE LOWER SUSQ VALLEY. THINK THERE IS A CHC OF SNOW SHOWERS AND BRIEFLY LOWER CONDITIONS THRU THE EVENING...BUT AFTER THAT CIG/VIS SHUD NOT POSE MUCH OF A CHALLENGE THERE. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ004-005-010. SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ024-033. && $$ SHORT TERM...DANGELO pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1012 PM EST TUE JAN 30 2007 .SHORT TERM /THROUGH TUESDAY NIGHT/... WILL SEND OUT A QUICK...LATE EVENING ZONE UPDATE TO FRESHEN UP THE WORDING FOR SNOW SHOWERS ACROSS THE REGION. ARCTIC FRONT HAS PUSHED EAST OF THE SUSI VALLEY...TAKING THE HEAVY SQUALLS WITH IT. WEAKENING MID LEVEL DEFORMATION SNOWS ACROSS THE NCENT MTNS WILL BRING ANOTHER INCH OR TWO TO SOME LOCATIONS OVER THE NEXT FEW HOURS WITHIN THE SNOW ADVISORY...WHICH SET TO EXPIRE AT MIDNIGHT EST. PERSISTENT LAKE EFFECT/OROGRAPHIC SNOWS ACROSS THE NW MTNS AND LAUREL HIGHLANDS RESPECTIVELY WILL CONTINUE TO ACCUMULATE A FEW MORE INCHES OVERNIGHT...SO NO CHANGES TO THE LAKE EFFECT/SNOW ADVISORIES FOR THOSE AREAS. ELSEWHERE...EXPECT FLURRIES AND A BRIEF HEAVIER SNOW SHOWER OVERNIGHT AS THE PRIMARY 700-500 HPA THERMAL TROUGH MOVES SE FROM THE GLAKES. ACCUMULATIONS WILL BE LESS THAN AN INCH ACROSS THE CENTRAL RIDGE AND VALLEY REGION. OVC LAYER WILL BREAK UP AFTER MIDNIGHT ACROSS THE LOWER SUSQ VALLEY AS DRIER DEWPOINTS IN THE UPPER SINGLE DIGITS ADVECT EAST VIA A DOWNSLOPE LLVL FLOW. TRIMMED HOURLY AND MIN TEMPS OVERNIGHT BY 2-4 DEG F IN MANY LOCATIONS. && .PREV DISCUSSION... /ISSUED 728 PM EST TUE JAN 30 2007/ SHORT TERM /THROUGH TONIGHT/... AREA OF INSTABILITY WITH TOTAL TOTALS NEAR 50 CROSSING THE SUSQ VALLEY...ALONG WITH A RATHER STRONG...ALBEIT COMPACT UPPER SHORT WAVE MOVE EAST OVER THE NCENT MTNS WILL BRING NUMEROUS SNOW SHOWERS AND LOCALLY HEAVY SNOW SQUALLS EARLY TONIGHT. ISSUED A SNOW ADVISORY ACROSS THE NCENT MTNS THROUGH MIDNIGHT WHERE A MESO-B MID LVL DEFORMATION ZONE AND CORRESPONDING EAST/WEST BELT OF ENHANCED 850-700 HPA OMEGA WILL LEAD TO SEVERAL INCHES OF NEW SNOW. SNOW SHOWERS AND SQUALLS WILL DIMINISH TO SCATTERED FLURRIES ACROSS THE CENTRAL VALLEYS AND SUSQ RIVER VALLEY LATE THIS EVENING. PREV DISCUSSION... /ISSUED 325 PM EST TUE JAN 30 2007/ SHORT TERM /TONIGHT THROUGH WEDNESDAY/... MESO ANAL SHOWS SFC LOW JUST WEST OF BFD AT 18Z...WITH THE COLD FRONT MOVING THRU SWRN PA. RUC SHOWS A POCKET OF RELATIVELY UNSTABLE AIR...LOW-MID LEVEL LAPSE RATES IN EXCESS OF 6C/KM AND T-TOTALS TOPPING 50...HELPING TRIGGER THE CURRENT SNOW SHOWERS AND SQUALLS MOVING ACROSS THE AREA. THE BEST FORCING/INSTABILITY STARTS TO WANE AFTER ABOUT 21Z ACCORDING TO SHORT TERM GUIDANCE...WITH THE FRONT EXPECTED TO CLEAR MY EASTERN ZONES BY 00Z. AFTER THE FROPA...WE WILL TRANSITION INTO A MORE TYPICAL NW FLOW REGIME WITH LAKE EFFECT AND OROGRAPHICALLY FORCED SNOWS IN THE WEST...AND ACTIVITY TAPERING OFF TO JUST SCATTERED SNOW SHOWERS AND FLURRIES THE FURTHER DOWNWIND OF THE LAKES AND LAURELS ONE GETS. ONLY CONCERN IS A HINT IN THE MODELS THAT THE UPPER-AIR PORTION OF THE OCCLUDED FRONT HANGS TOUGH FOR A TIME INTO NW PA...ENHANCING THE CONVERGENCE THERE INTO THE EVENING. THIS SHOWS UP AS A WELL DEFINED THERMAL RIDGE UP THRU ABOUT 850MB IN ALL THE SHORT RANGE GUIDANCE. THEY SHIFT THIS EAST OF THE AREA AFTER 03Z. WEDNESDAY WILL SEE CONDITIONS IMPROVING AS INVERSION HEIGHTS LOWER THROUGHOUT THE DAY. THE BEST CHANCE OF LINGERING SNOW WILL BE OVER WESTERN HIGH TERRAIN. ELSEWHERE WE SHUD SEE LITTLE MORE THAN FLURRIES. LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... UPPER TROFFING OVER EASTERN NORTH AMERICA LOOKS TO DOMINATE THE LONG TERM PERIOD. THIS WILL LEAD TO NEAR TO BELOW NORMAL TEMPERATURES EARLY IN THE PERIOD AND POSSIBLY SIGNIFICANTLY BELOW NORMAL TEMPERATURES LATE IN THE PERIOD. MOST OF THE PERIOD LOOKS DRY...BUT TWO OPPORTUNITIES FOR PCPN STAND OUT. A WEATHER SYSTEM THAT HAS BEEN ADVERTISED FOR SEVERAL DAYS TO AFFECT THE REGION LATE THURSDAY INTO FRIDAY CONTINUES TO LOOK COMPLEX...WITH VARYING RUN TO RUN MODEL SOLUTIONS. A SOUTHERN STREAM TROF IS FORECAST TO INDUCE CYCLOGENESIS OVER THE SOUTHEAST U.S. THURSDAY NIGHT WITH A NORTHERN STREAM TROF FORECAST TO SWING THROUGH THE REGION LATER FRIDAY. MUCH YET DEPENDS ON THE TRACK OF THE COASTAL LOW AND ANY PHASING THAT MAY TAKE PLACE BETWEEN THE TWO STREAMS. AT THIS TIME...THERE IS A HIGH PROBABILITY OF MEASURABLE ACROSS ALL OF THE CWA...WITH POTENTIAL FOR A SEVERAL INCH SNOWFALL ACROSS THE REGION...EVEN THE LOWER SUSQUEHANNA VALLEY...WHERE SNOWFALL SO FAR THIS SEASON IS LESS THAN AN INCH TOTAL. A PRONOUNCED ARCTIC TROF IS FORECAST TO MOVE THROUGH THE FORECAST AREA ON MONDAY...POTENTIALLY BRINGING IN THE COLDEST AIR YET THIS WINTER. AVIATION /20Z-18Z/... THE AFTERNOON`S WIDESPREAD IFR CAUSED BY THE SHORTWAVE AND SNOW SHOWERS SHUD BEGIN TO IMPROVE IN MOST AREAS THIS EVENING AS THE UPPER TROF MOVES EAST OF THE REGION AND A WEST-NORTHWEST FLOW DEVELOPS. LIKE A BROKEN RECORD THOUGH...JST/BFD WILL NOT SHARE IN THE IMPROVEMENT AS UPSLOPE AND PROXIMITY TO LAKE ERIE CONSPIRE TO KEEP BOTH TERMINALS MAINLY DOWN BELOW 3000/3 WITH FREQUENT SNOW SHOWERS BRINGING EVEN LOWER CONDITIONS. WILL PROB SEE AOO/UNV/IPT IMPROVE TO MVFR CEILINGS AND MOSTLY UNLIMITED VIS WITH ONLY OCNL SNOW SHOWERS BRINGING BRIEFLY REDUCED VIS AFTER 00Z...WITH VFR DEVELOPING SLOWLY LATER TONIGHT INTO EARLY WED MORNING. STILL A QUESTION AS TO WHETHER THE FAR SERN TERMINALS WILL SEE MUCH INCLEMENT WX AT ALL AS THE SYSTEM IS ALREADY MOISTURE STARVED AND DOWN-SLOPING FLOW WILL ONLY HELP IN MAKING MUCH OF THE SNOW SHOWER ACTIVITY DRY UP BEFORE IT MAKES IT INTO THE LOWER SUSQ VALLEY. THINK THERE IS A CHC OF SNOW SHOWERS AND BRIEFLY LOWER CONDITIONS THRU THE EVENING...BUT AFTER THAT CIG/VIS SHUD NOT POSE MUCH OF A CHALLENGE THERE. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST WEDNESDAY FOR PAZ004- 005-010. SNOW ADVISORY UNTIL 10 AM EST WEDNESDAY FOR PAZ024-033. SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ041-042-046- 053. && $$ SHORT TERM...LAMBERT pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 728 PM EST TUE JAN 30 2007 .SHORT TERM /THROUGH TONIGHT/... AREA OF INSTABILITY WITH TOTAL TOTALS NEAR 50 CROSSING THE SUSQ VALLEY...ALONG WITH A RATHER STRONG...ALBEIT COMPACT UPPER SHORT WAVE MOVE EAST OVER THE NCENT MTNS WILL BRING NUMEROUS SNOW SHOWERS AND LOCALLY HEAVY SNOW SQUALLS EARLY TONIGHT. ISSUED A SNOW ADVISORY ACROSS THE NCENT MTNS THROUGH MIDNIGHT WHERE A MESO-B MID LVL DEFORMATION ZONE AND CORRESPONDING EAST/WEST BELT OF ENHANCED 850-700 HPA OMEGA WILL LEAD TO SEVERAL INCHES OF NEW SNOW. SNOW SHOWERS AND SQUALLS WILL DIMINISH TO SCATTERED FLURRIES ACROSS THE CENTRAL VALLEYS AND SUSQ RIVER VALLEY LATE THIS EVENING. && .PREV DISCUSSION... /ISSUED 325 PM EST TUE JAN 30 2007/ SHORT TERM /TONIGHT THROUGH WEDNESDAY/... MESO ANAL SHOWS SFC LOW JUST WEST OF BFD AT 18Z...WITH THE COLD FRONT MOVING THRU SWRN PA. RUC SHOWS A POCKET OF RELATIVELY UNSTABLE AIR...LOW-MID LEVEL LAPSE RATES IN EXCESS OF 6C/KM AND T-TOTALS TOPPING 50...HELPING TRIGGER THE CURRENT SNOW SHOWERS AND SQUALLS MOVING ACROSS THE AREA. THE BEST FORCING/INSTABILITY STARTS TO WANE AFTER ABOUT 21Z ACCORDING TO SHORT TERM GUIDANCE...WITH THE FRONT EXPECTED TO CLEAR MY EASTERN ZONES BY 00Z. AFTER THE FROPA...WE WILL TRANSITION INTO A MORE TYPICAL NW FLOW REGIME WITH LAKE EFFECT AND OROGRAPHICALLY FORCED SNOWS IN THE WEST...AND ACTIVITY TAPERING OFF TO JUST SCATTERED SNOW SHOWERS AND FLURRIES THE FURTHER DOWNWIND OF THE LAKES AND LAURELS ONE GETS. ONLY CONCERN IS A HINT IN THE MODELS THAT THE UPPER-AIR PORTION OF THE OCCLUDED FRONT HANGS TOUGH FOR A TIME INTO NW PA...ENHANCING THE CONVERGENCE THERE INTO THE EVENING. THIS SHOWS UP AS A WELL DEFINED THERMAL RIDGE UP THRU ABOUT 850MB IN ALL THE SHORT RANGE GUIDANCE. THEY SHIFT THIS EAST OF THE AREA AFTER 03Z. WEDNESDAY WILL SEE CONDITIONS IMPROVING AS INVERSION HEIGHTS LOWER THROUGHOUT THE DAY. THE BEST CHANCE OF LINGERING SNOW WILL BE OVER WESTERN HIGH TERRAIN. ELSEWHERE WE SHUD SEE LITTLE MORE THAN FLURRIES. LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... UPPER TROFFING OVER EASTERN NORTH AMERICA LOOKS TO DOMINATE THE LONG TERM PERIOD. THIS WILL LEAD TO NEAR TO BELOW NORMAL TEMPERATURES EARLY IN THE PERIOD AND POSSIBLY SIGNIFICANTLY BELOW NORMAL TEMPERATURES LATE IN THE PERIOD. MOST OF THE PERIOD LOOKS DRY...BUT TWO OPPORTUNITIES FOR PCPN STAND OUT. A WEATHER SYSTEM THAT HAS BEEN ADVERTISED FOR SEVERAL DAYS TO AFFECT THE REGION LATE THURSDAY INTO FRIDAY CONTINUES TO LOOK COMPLEX...WITH VARYING RUN TO RUN MODEL SOLUTIONS. A SOUTHERN STREAM TROF IS FORECAST TO INDUCE CYCLOGENESIS OVER THE SOUTHEAST U.S. THURSDAY NIGHT WITH A NORTHERN STREAM TROF FORECAST TO SWING THROUGH THE REGION LATER FRIDAY. MUCH YET DEPENDS ON THE TRACK OF THE COASTAL LOW AND ANY PHASING THAT MAY TAKE PLACE BETWEEN THE TWO STREAMS. AT THIS TIME...THERE IS A HIGH PROBABILITY OF MEASURABLE ACROSS ALL OF THE CWA...WITH POTENTIAL FOR A SEVERAL INCH SNOWFALL ACROSS THE REGION...EVEN THE LOWER SUSQUEHANNA VALLEY...WHERE SNOWFALL SO FAR THIS SEASON IS LESS THAN AN INCH TOTAL. A PRONOUNCED ARCTIC TROF IS FORECAST TO MOVE THROUGH THE FORECAST AREA ON MONDAY...POTENTIALLY BRINGING IN THE COLDEST AIR YET THIS WINTER. AVIATION /20Z-18Z/... THE AFTERNOON`S WIDESPREAD IFR CAUSED BY THE SHORTWAVE AND SNOW SHOWERS SHUD BEGIN TO IMPROVE IN MOST AREAS THIS EVENING AS THE UPPER TROF MOVES EAST OF THE REGION AND A WEST-NORTHWEST FLOW DEVELOPS. LIKE A BROKEN RECORD THOUGH...JST/BFD WILL NOT SHARE IN THE IMPROVEMENT AS UPSLOPE AND PROXIMITY TO LAKE ERIE CONSPIRE TO KEEP BOTH TERMINALS MAINLY DOWN BELOW 3000/3 WITH FREQUENT SNOW SHOWERS BRINGING EVEN LOWER CONDITIONS. WILL PROB SEE AOO/UNV/IPT IMPROVE TO MVFR CEILINGS AND MOSTLY UNLIMITED VIS WITH ONLY OCNL SNOW SHOWERS BRINGING BRIEFLY REDUCED VIS AFTER 00Z...WITH VFR DEVELOPING SLOWLY LATER TONIGHT INTO EARLY WED MORNING. STILL A QUESTION AS TO WHETHER THE FAR SERN TERMINALS WILL SEE MUCH INCLEMENT WX AT ALL AS THE SYSTEM IS ALREADY MOISTURE STARVED AND DOWN-SLOPING FLOW WILL ONLY HELP IN MAKING MUCH OF THE SNOW SHOWER ACTIVITY DRY UP BEFORE IT MAKES IT INTO THE LOWER SUSQ VALLEY. THINK THERE IS A CHC OF SNOW SHOWERS AND BRIEFLY LOWER CONDITIONS THRU THE EVENING...BUT AFTER THAT CIG/VIS SHUD NOT POSE MUCH OF A CHALLENGE THERE. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST WEDNESDAY FOR PAZ004- 005-010. SNOW ADVISORY UNTIL 10 AM EST WEDNESDAY FOR PAZ024-033. SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ011-012-041- 042-046-053. && $$ SHORT TERM...LAMBERT pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 813 PM CST WED JAN 31 2007 .DISCUSSION... ALREADY HAVE HAD A QUICK SHOT OF SNOW ACROSS SOUTHERN HALF OF MIDDLE TN THIS EVE...WITH AREAS OVER ERN AR AND WRN TN GETTING UP TO 2 INCHES AS IT MOVED ACROSS THAT AREA. SOME OF OUR COUNTIES HAVE LIKELY HAD A DUSTING...A PREVIEW IF YOU WILL. LOOKING NOW AT BAND OF MODERATE TO HEAVY SLEET ACROSS CNTRL MS MOVING NE...THIS WILL POSSIBLY BE OUR FIRST MEASURABLE EPISODE FOR THIS EVENT...AND SHOULD BE IN FORM OF SNOW AS RUC SOUNDING FOR FYM SHOWS ALL SNOW ACROSS FAR SOUTHERN TN UNTIL ABOUT 09Z. MAY HAVE TO UPDATE FOR TIMING IF THIS BAND MOVES IN B4 MIDNITE. && .PREV DISCUSSION... /ISSUED 149 PM CST WED JAN 31 2007/ SHORT TERM...MODELS ARE IN REASONABLE AGREEMENT FOR MID TN WX...ESPECIALLY FOR A WINTER EVENT. GFS SEEMS CONSISTENT WITH THERMAL PROFILES FROM PREVIOUS RUN AND NAM ACTUALLY APPEARS A LITTLE COLDER IN THE NORTH AND PLATEAU. THIS MAY MEAN PRECIPITATION WILL STAY SNOW LONGER THEN PREVIOUSLY THOUGHT FOR THE NORTH HALF. QPF AND SNOWFALL OUTPUT FROM MODELS ACTUALLY IN PRETTY GOOD AGREEMENT AS WELL FOR MID TN. WITH ALL OF THIS SAID...SNOW IS HARD TO COME BY IN THIS REGION SO THERE ARE MANY THINGS THAT CAN SPOIL THIS EVENT (LACK OF MOISTURE...TOO WARM). THIS FORECAST IS NOT A BIG CHANGE FROM PREVIOUS PACKAGE...BUT THE LATEST MODEL DATA HAVE HELPED LEAN US TOWARD A STRONGER HEADLINE ON THE NORTH PLATEAU. AIR MASS IN PLACE IS COLD...TEMPERATURES NOT REACHING PROJECTED HIGHS TODAY ALTHOUGH WE MAY JUMP A FEW MORE DEGREES INTO THE LOW 30S LATE THIS AFTERNOON. MOISTURE WILL SPREAD RAPIDLY ACROSS THE REGION TONIGHT WITH ALL SIGNS POINTING TOWARD SNOW. VERY DRY LOW LEVELS WILL TAKE A WHILE TO MOISTEN...BUT MOST AREAS COULD HAVE AROUND 1 INCH BY DAYBREAK THURSDAY. FOR SOUTHERN TIER OF COUNTIES...SNOW WILL OCCUR TONIGHT WITH MAYBE AN INCH...BUT WILL QUICKLY TRANSITION TO RAIN THURSDAY MORNING. THERE MAY BE A MESSY TIME WITH FREEZING RAIN AND SLEET...BUT TEMPERATURES SHOULD WARM WELL INTO THE 30S BY LATE MORNING. FOR AREAS FARTHER NORTH...SNOW WILL DEVELOP LATE TONIGHT AND CONTINUE THROUGH MID MORNING THURSDAY. THEN THE MIX OF CHANGE TO SLEET AND RAIN WILL OCCUR AFTER 16Z WITH TEMPERATURES RISING ABOVE FREEZING. THESE AREAS INCLUDING NASHVILLE WILL PROBABLY SEE 1 TO 2 INCHES BEFORE MIDDAY. MOST OF THE MID STATE WILL BE UNDER AN ADVISORY WHILE THE HIGHER ELEVATIONS OF THE NORTH PLATEAU ARE EXPECTED TO REACH WINTER STORM WARNING CRITERIA. FORECAST SOUNDINGS SUGGEST MAINLY SNOW THROUGH MUCH OF THE DAY FOR CROSSVILLE AND JAMESTOWN...SO WE ARE FORECASTING UP TO 4 INCHES THERE. STILL A CHANCE OF PRECIPITATION LATE THURSDAY AND INTO THE NIGHT...BUT MARGINAL TEMPERATURES AND LIGHT PRECIP...SO NOT CALLING FOR ADDITIONAL ACCUMULATIONS AT THIS TIME. TEMPERATES MAY FALL BELOW FREEZING CAUSING MORE TRAVEL PROBLEMS. LONG TERM...A SERIES OF COLD BLASTS WILL INVADE THE REGION IN THE EXTENDED FORECAST. DISTURBANCES MAY BRING PERIODS OF SNOW SHOWERS AND LOCALIZED MINOR SNOW ACCUMULATIONS. FOR NOW JUST MENTIONING SOME FLURRIES WITH MOST SIGNIFICANT FRONTS. FOCUS SHOULD BE ON VERY COLD READINGS...WHICH WILL HAVE MOST AREAS IN THE SINGLE DIGITS FOR LOWS AND ONLY 20S FOR HIGHS EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 26 37 30 36 / 90 100 70 10 CLARKSVILLE 26 33 28 34 / 90 100 70 10 CROSSVILLE 25 33 29 33 / 90 100 70 20 && .OHX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM MIDNIGHT THURSDAY TO 4 PM THURSDAY FOR THE FOLLOWING ZONES: CUMBERLAND...FENTRESS...OVERTON...PICKETT... PUTNAM...VAN BUREN...AND WHITE. WINTER WEATHER ADVISORY FROM MIDNIGHT THURSDAY TO 4 PM THURSDAY FOR THE FOLLOWING ZONES: BENTON...CANNON...CHEATHAM...CLAY... DAVIDSON...DEKALB...DICKSON...HICKMAN...HOUSTON...HUMPHREYS... JACKSON...MACON...MONTGOMERY...PERRY...ROBERTSON...RUTHERFORD... SMITH...STEWART...SUMNER...TROUSDALE...WARREN...WILLIAMSON...AND WILSON. WINTER WEATHER ADVISORY FROM MIDNIGHT THURSDAY TO 10 AM THURSDAY FOR THE FOLLOWING ZONES: BEDFORD...COFFEE...GILES...GRUNDY... LAWRENCE...LEWIS...MARSHALL...MAURY...AND WAYNE. && $$ MAG tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 342 PM CST WED JAN 31 2007 .UPDATE... QUICK UPDATE TO ADD MISSISSIPPI COUNTY IN ARKANSAS AND LAKE...DYER AND OBION COUNTIES IN TENNESSEE TO THE SNOW ADVISORTY. RADAR AND SURFACE TRENDS INDICATE THE SNOW MOVING EAST. ROAD CONDITIONS GETTING SLIPPERY VERY QUICKLY DUE TO COLD TEMPERATURES. LATEST RUC MODEL SOME HELP WITH PROGRESSION OF SNOWFALL...BUT STRONGER LOW LEVEL COLD AIR THAN ANTICIPATED PROVIDING BETTER THAN FORECAST ISENTROPIC UPGLIDE FOR LIFTED MOTION && .PREV DISCUSSION... /ISSUED 302 PM CST WED JAN 31 2007/ SYNOPSIS... COLD HIGH RETREATING OFF THE EAST COAST. RADAR TRENDS SHOW PRECIPITATION BREAKING OUT ACROSS THE PLAINS AND ARKANSAS THIS AFTERNOON. WITH THE LOW LEVELS SO DRY...MUCH OF THE PRECIPITATION INDICATED ON RADAR IS NOT REACHING THE GROUND. HOWEVER OVER NORTHEAST ARKANSAS IT IS. WITH LOW LEVELS SO COLD SNOWFALL ACCUMULATING ON ROADS FAST. ACTUAL TEMPERATURES COLDER THAN THE MODELS BY GENERALLY 5 DEGREES. WITH MODELS NOT HANDLING THE LOW LEVEL TEMPERATURES AT THIS TIME THIS MAY HAVE IMPLICATIONS TO OUR SHORT TERM FORECAST. SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)... RADAR TRENDS SHOW SNOWFALL TO CONTINUE OVER NORTHEAST ARKANSAS FOR SOME TIME. ACCUMULATIONS OF AROUND AN INCH ARE EXPECTED. WITH TEMPS IN THE LOWER 20S ALL OF THE SNOW IS STICKING NICELY. HAVE DECIDED TO GO WITH AN ADVISORY THROUGH MID-MORNING THURSDAY. FOR THE REST OF THE AREA MIXED PRECIPITATION EXPECTED AFTER MIDNIGHT THROUGH THURSDAY FOR MUCH OF THE MID-SOUTH. MUCH OF THE LIFT FOR THIS EVENT IS ISENTROPIC AND BROAD IN NATURE. ALTHOUGH JET STREAK IS FAIRLY STRONG THERE IS LITTLE IN THE WAY OF SURFACE CYCLOGENESIS. CONSEQUENTLY PRECIPITATION AMOUNTS WILL BE BROAD AND LIGHT THROUGH THURSDAY NIGHT. REGARDLESS...IT DOESN`T TAKE MUCH WINTER PRECIPITATION TO CAUSE TRAVEL ISSUES IN THE MIDSOUTH. THIS COUPLED WITH THE FIRST EVENT OF THE SEASON AND WE HAVE A NEED TO PINPOINT THE IMPACTS. OUR PRECIPITATION WILL COME IN TWO BURSTS. TONIGHT...MIXED PRECIPITATION IS EXPECTED TO DEVELOP WITH THE HEAVIEST OCCURRING IN NORTHEAST MISSISSIPPI IN THE LOCATION OF THE BEST ISENTROPIC LIFT AND MOISTURE. THE PROBLEM IS THERMAL PROFILES INDICATE AN ONSET OF FREEZING RAIN FROM FULTON TO TUPELO TO OXFORD. THIS IS WHERE TRAVEL WILL BE IMPACTED MOST WITH PRECIPITATION TURNING OVER TO RAIN LATER ON THURSDAY. AN ADVISORY WILL BE NEEDED IN THIS AREA LATE TONIGHT AND EARLY THURSDAY. TO THE NORTH AND NORTHWEST OF THIS AREA...THE PRECIPITATION SHOULD BEGIN AS SNOW...HOWEVER AMOUNTS ARE IN QUESTION WITH ACCUMULATIONS RANGING FROM AN INCH TO ONLY A DUSTING. THIS MAKES IT HARD TO DETERMINE WHETHER WE SHOULD ISSUE AN ADVISORY. FOR NOW WE`LL HOLD OFF AND WAIT ON ANY WIDESPREAD ADVISORIES...EXCEPT IN NORTHEAST ARKANSAS AND MISSOURI BOOTHEEL...UNTIL WE CAN GET A BETTER HANDLE ON THE EVOLUTION OF THE PRECIPITATION AMOUNTS. THURSDAY AND THURSDAY NIGHT ARE PROBLEMATIC. ANOTHER WEAK SHORTWAVE MOVES INTO MS/AL RESULTING IN PRECIPITATION REDEVELOPING IN THE AFTERNOON. AGAIN QUESTION WILL BE THE TYPE. FOR NOW BELIEVE THE MODEL THERMAL PROFILES MAY BE TOO WARM IN THE LOWER LEVELS (THEY SUGGEST A DRY ADIABATIC PROFILE WITH PRECIPITATION?) WILL KEEP RAIN FOR THE SOUTH THIRD OF THE FORECAST AREA...A MIX OF THE MIDDLE THIRD AND ALL SNOW TO THE NORTH. AGAIN PRECIPITATION AMOUNTS WILL BE LIGHT...BUT DEPENDING ON HOW TEMPERATURES PLAY OUT A WINTER WEATHER ADVISORY MAY BE NEEDED. WILL USE THE UKMET/GFS/CANADIAN FOR THURSDAY NIGHT AND FRIDAY. NAM IS TOO SLOW WITH COLD AIR SEEPING IN. CONSEQUENTLY WILL GO LOWER THAN GUIDANCE WITH FLURRIES POSSIBLE IN THE STRONG COLD AIR ADVECTION. OVERALL THE TEMPERATURE GUIDANCE THROUGH THIS PERIOD LOOKS WARM. BUT THIS SHOULD NOT BE SURPRISING WITH LOW LEVEL COLD AIR IN PLACE. ...BELLES... LONG TERM (SATURDAY THROUGH WEDNESDAY)...LONG RANGE MODELS IN GENERAL AGREEMENT WITH AN ARCTIC LOW PINWHEELING AROUND HUDSON BAY THROUGH THE PERIOD AND A LONGWAVE TROUGH MOVING THROUGH THE LOWER MISSISSIPPI VALLEY ON SUNDAY. ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION ON MONDAY WITH COLD HIGH PRESSURE BUILDING BACK INTO THE AREA FOR NEXT WEEK. ADJUSTED TEMPERATURES TOWARD THE LOW END OF THE GFS ENSEMBLE GUIDANCE SINCE OPERATIONAL GFS NUMERICAL GUIDANCE SEEMS TO BE TOO WARM THIS WEEKEND INTO EARLY NEXT WEEK BASED ON UPPER AIR PATTERN AND VERY COLD 850MB TEMPERATURES. ...CJC... && .PRELIMINARY POINT TEMPS/POPS... MEM 27 38 30 38 / 80 100 60 10 MKL 23 36 28 35 / 80 90 60 10 JBR 20 34 24 34 / 80 90 60 10 TUP 29 39 33 41 / 90 100 60 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...SNOW ADVISORY UNTIL 9 AM CST THURSDAY FOR CLAY-CRAIGHEAD-GREENE- LAWRENCE-MISSISSIPPI-RANDOLPH. MO...SNOW ADVISORY UNTIL 9 AM CST THURSDAY FOR DUNKLIN-PEMISCOT. MS...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST THURSDAY FOR ALCORN-BENTON(MS)-ITAWAMBA-LAFAYETTE-LEE(MS)- MARSHALL-PONTOTOC-PRENTISS-TIPPAH-TISHOMINGO-UNION. TN...SNOW ADVISORY UNTIL 9 AM CST THURSDAY FOR DYER-LAKE-OBION. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST THURSDAY FOR HARDEMAN-HARDIN-MCNAIRY. && $$ tn AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE FORT WORTH TX 730 PM CST WED JAN 31 2007 .UPDATE... LARGE SCALE SUBSIDENCE BEHIND EXITING SHORT WAVE IS CURRENTLY IN PLACE OVER NORTH TEXAS. OTHER THAN A FEW SPRINKLES DEVELOPING LATE IN THE EVENING IT NOW APPEARS THAT ANY MEASURABLE RAIN WILL HOLD OFF OVER NORTH TEXAS UNTIL AFTER MIDNIGHT. THEREFORE...WE WILL LOWER POPS TO SLIGHT CHANCES THE REST OF THE EVENING...BUT KEEP HIGH RAIN CHANCES OVERNIGHT AND THURSDAY MORNING. THE COLD FRONT CONTINUES TO SURGE SOUTHWARD OVER WEST TEXAS BUT THE EASTERN PORTION OF THE FRONT IS STILL NORTH OF OKC. WE EXPECT THE FRONT TO MOVE THROUGH THE WESTERN PORTIONS OF NORTH TEXAS AFTER MIDNIGHT AND THROUGH THE REMAINDER OF THE REGION AFTER SUNRISE THURSDAY. AS OF NOW...LOW LEVEL TEMPERATURE PROFILES SUGGEST THAT ALL PRECIPITAION SHOULD FALL AS RAIN SO WE WILL LEAVE THE FORECAST AS SUCH. HOWEVER...WE WILL BE EXAMINING THE 00Z MODELS AS WELL AS SURFACE TRENDS CLOSELY THROUGH THE EVENING. OTHER THAN LOWERING THE EVENING POPS...WE WILL ADJUST CLOUD COVER...TEMPS...DEW POINTS AND WINDS BASED ON CURRENT TRENDS. 79. && .AVIATION... 520 PM CST SHORT TERM CLEARING AREAS HAS MOVED INTO THE DFW TRACON AREA WITH BOTH IR AND VIS SATELLITE IMAGERY SHOWING THE BACK EDGE NEAR A SPS-DFW-ACT LINE. LOOKING AT THE FORECAST TRENDS OVERNIGHT RUC AND GFS BOTH INDICATING RETURN MOISTURE FROM LOW LEVEL JET WITH THE LAYER FROM SURFACE TO 2K FEET NEARLY SATURATED BY 09Z SO EXPECT IFR CONDITIONS FOR AIRPORTS THURSDAY AM. WILL CONTINUE WITH LIGHT RAIN OR DRIZZLE DEVELOPING BETWEEN MIDNIGHT AND 300 AM THURSDAY MORNING AND CONTINUING THROUGH MOST OF THURSDAY. WIND SOUTH TO SOUTHEAST OVERNIGHT BECOMING MORE EASTERLY THURSDAY AM AND NORTHERLY THURSDAY AFTERNOON WITH WIND SPEED BETWEEN 6-10 KNOTS. 50 && .DISCUSSION... MUCH OF NORTH TEXAS IS EXPERIENCING A BRIEF BREAK IN PRECIP COURTEOUSY OF SUBSIDENCE BEHIND THE DEPARTING SHORTWAVE. LIGHT RETURNS OF MOSTLY RAIN CONTINUE ACROSS THE NORTHERN AND EASTERN ZONES. TEMPERATURES OUTSIDE OF THE PRECIP AREAS ARE NOW REACHING THE UPPER 30S TO MID 40S. THE NEXT SHORTWAVE TO AFFECT NORTH TEXAS LATER TONIGHT THROUGH TOMORROW IS NOW LOCATED NEAR BAJA. A WEAK COLD FRONT NOW BISECTING THE COUNTRY WILL MOVE INTO NORTH TEXAS TOMORROW. THIS FRONT WILL LIKELY SLOW DOWN AND BECOME SOMEWHAT ILL-DEFINED AS UPPER LEVEL ENERGY BECOMES STRUNG OUT IN STRONG FLOW ALOFT. PRECIP CHANCES THROUGH TOMORROW WILL BE THE BEST IN THE SOUTH AND EAST...WHERE FRONTOGENESIS WILL BE MAXIMIZED. EXPECT THIS ROUND OF PRECIP TO BE ALL LIQUID AS CLOUDS AND RAIN WILL KEEP TEMPERATURES ABOVE FREEZING...ALTHOUGH 18Z RUNS HAVE TRENDED SLIGHTLY COLDER THAN THE 12Z RUNS. IF THE COLD AIR ARRIVES EARLIER AND DEEPER THAN THE CURRENT THINKING...A WINTRY MIX MAY NEED TO BE INCLUDED IN THE NORTHERN ZONES. THE FRONT WILL REMAIN IN THE SOUTHERN CWA TOMORROW...EFFECTIVELY KEEPING THE COLDER AIR BOTTLED UP IN THE NORTHERN TWO-THIRDS OF THE CWA. THIS WILL CREATE QUITE A DIFFERENCE BETWEEN DIURNAL TEMPERATURES IN THE NORTH AND THE SOUTH. UPPER LEVEL PATTERN WILL BECOME MORE MERIDIONAL OVER THE NEXT FEW DAYS AS TALL RIDGING COMES ASHORE ON THE WEST COAST...PUSHING THE BROAD TROUGH FARTHER EAST. SHORTWAVE ENERGY WILL ROUND THE BASE OF THE UPPER LEVEL TROUGH AND SKIRT THE NORTHERN SECTIONS FRIDAY AND SATURDAY. IN ADDITION...A STRONG ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS ON FRIDAY. MOISTURE WILL BE LIMITED...AND HAVE ONLY INCLUDED A SLIGHT CHANCE IN THE NORTHERN ZONES. TEMPERATURE PROFILES WILL BE COLD ENOUGH IN THE CHILLY AIR BEHIND THE FRONT FOR PRECIP TO FALL AS A MIX OF RAIN AND SNOW. TEMPERATURES WILL BEGIN TO REBOUND SOMEWHAT BY SUNDAY. HOWEVER... THIS WILL BE TEMPERED BY A REINFORCING SHOT OF COLD AIR ON MONDAY. THE NEXT CHANCE OF RAIN LOOKS TO BE NEXT TUESDAY AS ISENTROPIC LIFT BECOMES ESTABLISHED ON THE 285K AND 290K PLANES. /13 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 37 46 31 41 26 / 70 50 10 10 10 WACO, TX 42 54 36 51 34 / 80 50 10 10 10 PARIS, TX 33 40 32 39 22 / 70 80 20 20 10 DENTON, TX 34 45 30 37 23 / 60 50 10 10 10 MCKINNEY, TX 37 44 31 38 24 / 70 70 10 10 10 DALLAS, TX 38 48 36 43 30 / 70 60 10 10 10 TERRELL, TX 37 47 33 42 30 / 80 80 10 10 10 CORSICANA, TX 38 51 35 46 31 / 80 80 10 10 10 TEMPLE, TX 41 56 38 56 34 / 80 50 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 42/13 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 322 PM CST WED JAN 31 2007 ...AVIATION SHORT TERM CLEARING AREAS HAS MOVED INTO THE DFW TRACON AREA WITH BOTH IR AND VIS SATELLITE IMAGERY SHOWING THE BACK EDGE NEAR A SPS-DFW-ACT LINE. LOOKING AT THE FORECAST TRENDS OVERNIGHT RUC AND GFS BOTH INDICATING RETURN MOISTURE FROM LOW LEVEL JET WITH THE LAYER FROM SURFACE TO 2K FEET NEARLY SATURATED BY 09Z SO EXPECT IFR CONDITIONS FOR AIRPORTS THURSDAY AM. WILL CONTINUE WITH LIGHT RAIN OR DRIZZLE DEVELOPING BETWEEN MIDNIGHT AND 300 AM THURSDAY MORNING AND CONTINUING THROUGH MOST OF THURSDAY. WIND SOUTH TO SOUTHEAST OVERNIGHT BECOMING MORE EASTERLY THURSDAY AM AND NORTHERLY THURSDAY AFTERNOON WITH WIND SPEED BETWEEN 6-10 KNOTS. 50 && .DISCUSSION... MUCH OF NORTH TEXAS IS EXPERIENCING A BRIEF BREAK IN PRECIP COURTEOUSY OF SUBSIDENCE BEHIND THE DEPARTING SHORTWAVE. LIGHT RETURNS OF MOSTLY RAIN CONTINUE ACROSS THE NORTHERN AND EASTERN ZONES. TEMPERATURES OUTSIDE OF THE PRECIP AREAS ARE NOW REACHING THE UPPER 30S TO MID 40S. THE NEXT SHORTWAVE TO AFFECT NORTH TEXAS LATER TONIGHT THROUGH TOMORROW IS NOW LOCATED NEAR BAJA. A WEAK COLD FRONT NOW BISECTING THE COUNTRY WILL MOVE INTO NORTH TEXAS TOMORROW. THIS FRONT WILL LIKELY SLOW DOWN AND BECOME SOMEWHAT ILL-DEFINED AS UPPER LEVEL ENERGY BECOMES STRUNG OUT IN STRONG FLOW ALOFT. PRECIP CHANCES THROUGH TOMORROW WILL BE THE BEST IN THE SOUTH AND EAST...WHERE FRONTOGENESIS WILL BE MAXIMIZED. EXPECT THIS ROUND OF PRECIP TO BE ALL LIQUID AS CLOUDS AND RAIN WILL KEEP TEMPERATURES ABOVE FREEZING...ALTHOUGH 18Z RUNS HAVE TRENDED SLIGHTLY COLDER THAN THE 12Z RUNS. IF THE COLD AIR ARRIVES EARLIER AND DEEPER THAN THE CURRENT THINKING...A WINTRY MIX MAY NEED TO BE INCLUDED IN THE NORTHERN ZONES. THE FRONT WILL REMAIN IN THE SOUTHERN CWA TOMORROW...EFFECTIVELY KEEPING THE COLDER AIR BOTTLED UP IN THE NORTHERN TWO-THIRDS OF THE CWA. THIS WILL CREATE QUITE A DIFFERENCE BETWEEN DIURNAL TEMPERATURES IN THE NORTH AND THE SOUTH. UPPER LEVEL PATTERN WILL BECOME MORE MERIDIONAL OVER THE NEXT FEW DAYS AS TALL RIDGING COMES ASHORE ON THE WEST COAST...PUSHING THE BROAD TROUGH FARTHER EAST. SHORTWAVE ENERGY WILL ROUND THE BASE OF THE UPPER LEVEL TROUGH AND SKIRT THE NORTHERN SECTIONS FRIDAY AND SATURDAY. IN ADDITION...A STRONG ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS ON FRIDAY. MOISTURE WILL BE LIMITED...AND HAVE ONLY INCLUDED A SLIGHT CHANCE IN THE NORTHERN ZONES. TEMPERATURE PROFILES WILL BE COLD ENOUGH IN THE CHILLY AIR BEHIND THE FRONT FOR PRECIP TO FALL AS A MIX OF RAIN AND SNOW. TEMPERATURES WILL BEGIN TO REBOUND SOMEWHAT BY SUNDAY. HOWEVER... THIS WILL BE TEMPERED BY A REINFORCING SHOT OF COLD AIR ON MONDAY. THE NEXT CHANCE OF RAIN LOOKS TO BE NEXT TUESDAY AS ISENTROPIC LIFT BECOMES ESTABLISHED ON THE 285K AND 290K PLANES. /13 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 37 46 31 41 26 / 70 50 10 10 10 WACO, TX 42 54 36 51 34 / 80 50 10 10 10 PARIS, TX 33 40 32 39 22 / 70 80 20 20 10 DENTON, TX 34 45 30 37 23 / 60 50 10 10 10 MCKINNEY, TX 37 44 31 38 24 / 70 70 10 10 10 DALLAS, TX 38 48 36 43 30 / 70 60 10 10 10 TERRELL, TX 37 47 33 42 30 / 80 80 10 10 10 CORSICANA, TX 38 51 35 46 31 / 80 80 10 10 10 TEMPLE, TX 41 56 38 56 34 / 80 50 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 42/13 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1152 PM CST TUE JAN 30 2007 .UPDATE... LATEST SURFACE ANALYSIS INDICATES TEMPERATURES ACROSS THE BIG COUNTRY HAVE FALLEN A LITTLE FASTER THAN WE WERE ANTICIPATING. THE STRATUS...CURRENTLY MOVING NORTH ACROSS THE CONCHO VALLEY...WILL LIKELY NOT MAKE IT INTO THE BIG COUNTRY FOR ANOTHER COUPLE HOURS. THUS...JUST SENT AN UPDATE TO LOWER OVERNIGHT LOWS A COUPLE DEGREES...MAINLY ACROSS THE BIG COUNTRY. ALSO...ADJUSTED SKY CONDITIONS FOR THE REMAINDER OF TONIGHT. AS FOR PRECIPITATION FOR THE REMAINDER OF TONIGHT...LATEST RUC SOUNDING DATA SUGGESTS COLUMN OVER THE BIG COUNTRY WILL CONTINUE TO SATURATE AND REMAIN AT OR JUST BELOW THE FREEZING MARK UNTIL AROUND 12Z. THEN...A WARMER LAYER...CENTERED AROUND 800 MB...EDGES A COUPLE DEGREES C ABOVE FREEZING. SO...DECIDED TO MAINTAIN THE MENTION OF SNOW FOR THE REMAINDER OF TONIGHT ACROSS THE BIG COUNTRY. HOWEVER...AS BEFORE...WE EXPECT LITTLE OR NO ACCUMULATION. ELSEWHERE...LIQUID PRECIPITATION STILL LOOKS BEST. 23/HUBER && .PREV DISCUSSION... /ISSUED 1127 PM CST TUE JAN 30 2007/ AVIATION... AREAS OF MVFR CIGS OF BKN010-020 ARE EXPECTED TO DEVELOP ACROSS WEST CENTRAL TEXAS AFTER 31/11Z...WITH MVFR CIGS BECOMING MORE WIDESPREAD AFTER 31/14Z. SCT SHRA WILL DEVELOP ACROSS WEST CENTRAL TEXAS AFTER 31/09Z...POSSIBLY MIXED WITH SLEET AND SNOW ACROSS THE BIG COUNTRY UNTIL 31/18Z. ALSO...SURFACE WINDS WILL BECOME SOUTHERLY AT 10 TO 15 KNOTS LATE TONIGHT AND WEDNESDAY. 21 PREV DISCUSSION... /ISSUED 914 PM CST TUE JAN 30 2007/ UPDATE... LATEST SATELLITE AND WSR-88D DATA INDICATE THE POTENTIAL FOR SHOWERS ACROSS THE NORTHERN BIG COUNTRY...WITH THE BEST RADAR RETURN CURRENTLY OVER HASKELL COUNTY AND THROCKMORTON COUNTY. SURFACE WINDS ACROSS WEST CENTRAL TEXAS REMAIN MAINLY NORTHEAST. HOWEVER...LATEST RUC DATA INDICATE WINDS WILL BECOME SOUTHEAST OVERNIGHT. THUS...CURRENT FORECAST LOOKS ON TRACK. 23/HUBER PREV DISCUSSION... /ISSUED 327 PM CST TUE JAN 30 2007/ SHORT TERM... UPPER LEVEL CLOUDS WERE REDEVELOPING FROM THE WEST WITH UPSLOPE FLOW BEHIND COLD FRONT THIS AFTERNOON (AT LEAST SOUTH OF INTERSTATE 20). WATER VAPOR LOOP INDICATED UPPER LEVEL LOW WAS OVER SOUTHERN CALIFORNIA...WITH SOME LIFT INDICATED AHEAD OF THE SYSTEM OVER ARIZONA AND NEW MEXICO. MID LEVEL MOISTURE INCREASES LATE TONIGHT AS UPPER LEVEL LOW SHEARS OUT AND MOVES TOWARD THE REGION...AND RIDING OVER THE COLD FRONT. MAY SEE SOME LIGHT PRECIPITATION TOWARD MORNING. GFS FORECAST SOUNDING INDICATE THIS TO BE SNOW OR SNOW/RAIN MIXTURE IN THE BIG COUNTRY...IF IT OCCURS. DO NOT ANTICIPATED ACCUMULATIONS. WENT A LITTLE LOWER ON TEMPERATURES (FROM MAV GUIDANCE) ACROSS THE BIG COUNTRY WHERE IT MAY TAKE A LITTLE LONGER FOR CLOUD COVER TO COME IN TONIGHT. LONG TERM... BEST SHORTWAVE/LIFT COMES IN WEDNESDAY TONIGHT. TEMPERATURES PROFILES INDICATE THIS TO BE MAINLY RAIN...THROUGH ITS POSSIBLE SOME SLEET MAY OCCUR IN NORTHERN SECTIONS OF THE BIG COUNTRY. RAIN CHANCES TAPER OFF THURSDAY MORNING. NEXT COLD FRONT COMES IN ON FRIDAY...KEEPING TEMPERATURES ON THE COOL SIDE THIS WEEKEND. MOISTURE TOO SHALLOW FOR ANY SIGNIFICANT RAIN THIS WEEKEND...THOUGH CANT RULE OUT A SPRINKLE OR TWO. ECMWF DIFFER IN HANDLING ANOTHER COLD FRONT NEXT WEEK. ECMWF HAS COLD FRONT MONDAY...WHICH BUILDS IN VERY STRONGLY THROUGH TUESDAY. THE GFS PUSHES MOST OF THE COLD AIR TO THE EAST ON MONDAY...WITH ONLY A WEAKER COLD FRONT. IT THEN BRINGS WEST CENTRAL TEXAS IN SOUTHERLY WARM ADVECTION TUESDAY...BEFORE A SECOND STRONG COLD FRONT MOVES IN TUESDAY NIGHT. WILL GO WITH THE COLDER ECMWF SOLUTION FOR NOW...AS A LOT OF TIMES FRONT GETS CHANNELS AGAINST THE ROCKY MOUNTAINS. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 29 48 37 48 / 20 30 50 20 SAN ANGELO 34 51 40 55 / 20 20 50 20 JUNCTION 37 49 44 60 / 20 20 50 20 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/23 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1127 PM CST TUE JAN 30 2007 .AVIATION... AREAS OF MVFR CIGS OF BKN010-020 ARE EXPECTED TO DEVELOP ACROSS WEST CENTRAL TEXAS AFTER 31/11Z...WITH MVFR CIGS BECOMING MORE WIDESPREAD AFTER 31/14Z. SCT SHRA WILL DEVELOP ACROSS WEST CENTRAL TEXAS AFTER 31/09Z...POSSIBLY MIXED WITH SLEET AND SNOW ACROSS THE BIG COUNTRY UNTIL 31/18Z. ALSO...SURFACE WINDS WILL BECOME SOUTHERLY AT 10 TO 15 KNOTS LATE TONIGHT AND WEDNESDAY. 21 && .PREV DISCUSSION... /ISSUED 914 PM CST TUE JAN 30 2007/ UPDATE... LATEST SATELLITE AND WSR-88D DATA INDICATE THE POTENTIAL FOR SHOWERS ACROSS THE NORTHERN BIG COUNTRY...WITH THE BEST RADAR RETURN CURRENTLY OVER HASKELL COUNTY AND THROCKMORTON COUNTY. SURFACE WINDS ACROSS WEST CENTRAL TEXAS REMAIN MAINLY NORTHEAST. HOWEVER...LATEST RUC DATA INDICATE WINDS WILL BECOME SOUTHEAST OVERNIGHT. THUS...CURRENT FORECAST LOOKS ON TRACK. 23/HUBER PREV DISCUSSION... /ISSUED 327 PM CST TUE JAN 30 2007/ SHORT TERM... UPPER LEVEL CLOUDS WERE REDEVELOPING FROM THE WEST WITH UPSLOPE FLOW BEHIND COLD FRONT THIS AFTERNOON (AT LEAST SOUTH OF INTERSTATE 20). WATER VAPOR LOOP INDICATED UPPER LEVEL LOW WAS OVER SOUTHERN CALIFORNIA...WITH SOME LIFT INDICATED AHEAD OF THE SYSTEM OVER ARIZONA AND NEW MEXICO. MID LEVEL MOISTURE INCREASES LATE TONIGHT AS UPPER LEVEL LOW SHEARS OUT AND MOVES TOWARD THE REGION...AND RIDING OVER THE COLD FRONT. MAY SEE SOME LIGHT PRECIPITATION TOWARD MORNING. GFS FORECAST SOUNDING INDICATE THIS TO BE SNOW OR SNOW/RAIN MIXTURE IN THE BIG COUNTRY...IF IT OCCURS. DO NOT ANTICIPATED ACCUMULATIONS. WENT A LITTLE LOWER ON TEMPERATURES (FROM MAV GUIDANCE) ACROSS THE BIG COUNTRY WHERE IT MAY TAKE A LITTLE LONGER FOR CLOUD COVER TO COME IN TONIGHT. LONG TERM... BEST SHORTWAVE/LIFT COMES IN WEDNESDAY TONIGHT. TEMPERATURES PROFILES INDICATE THIS TO BE MAINLY RAIN...THROUGH ITS POSSIBLE SOME SLEET MAY OCCUR IN NORTHERN SECTIONS OF THE BIG COUNTRY. RAIN CHANCES TAPER OFF THURSDAY MORNING. NEXT COLD FRONT COMES IN ON FRIDAY...KEEPING TEMPERATURES ON THE COOL SIDE THIS WEEKEND. MOISTURE TOO SHALLOW FOR ANY SIGNIFICANT RAIN THIS WEEKEND...THOUGH CANT RULE OUT A SPRINKLE OR TWO. ECMWF DIFFER IN HANDLING ANOTHER COLD FRONT NEXT WEEK. ECMWF HAS COLD FRONT MONDAY...WHICH BUILDS IN VERY STRONGLY THROUGH TUESDAY. THE GFS PUSHES MOST OF THE COLD AIR TO THE EAST ON MONDAY...WITH ONLY A WEAKER COLD FRONT. IT THEN BRINGS WEST CENTRAL TEXAS IN SOUTHERLY WARM ADVECTION TUESDAY...BEFORE A SECOND STRONG COLD FRONT MOVES IN TUESDAY NIGHT. WILL GO WITH THE COLDER ECMWF SOLUTION FOR NOW...AS A LOT OF TIMES FRONT GETS CHANNELS AGAINST THE ROCKY MOUNTAINS. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 31 48 37 48 / 20 30 50 20 SAN ANGELO 34 51 40 55 / 20 20 50 20 JUNCTION 37 49 44 60 / 20 20 50 20 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 914 PM CST TUE JAN 30 2007 .UPDATE... LATEST SATELLITE AND WSR-88D DATA INDICATE THE POTENTIAL FOR SHOWERS ACROSS THE NORTHERN BIG COUNTRY...WITH THE BEST RADAR RETURN CURRENTLY OVER HASKELL COUNTY AND THROCKMORTON COUNTY. SURFACE WINDS ACROSS WEST CENTRAL TEXAS REMAIN MAINLY NORTHEAST. HOWEVER...LATEST RUC DATA INDICATE WINDS WILL BECOME SOUTHEAST OVERNIGHT. THUS...CURRENT FORECAST LOOKS ON TRACK. 23/HUBER && .PREV DISCUSSION... /ISSUED 533 PM CST TUE JAN 30 2007/ AVIATION... COLD FRONT HAS MOVED SOUTH OF WEST CENTRAL TEXAS...WITH SURFACE NORTH TO NORTHEAST OF AROUND 10 KNOTS. SURFACE WINDS WILL RETURN TO SOUTHERLY AT 10 TO 15 KNOTS ON WEDNESDAY. AREAS OF MVFR CIGS OF BKN010-020 ARE EXPECTED ACROSS WEST CENTRAL TEXAS AFTER 31/09Z ..WITH MVFR CIGS BECOMING MORE WIDESPREAD AFTER 31/13Z. SCT SHRA WILL DEVELOP ACROSS WEST CENTRAL TEXAS AFTER 31/09Z...POSSIBLY MIXED WITH SLEET AND SNOW ACROSS THE BIG COUNTRY. 21 PREV DISCUSSION... /ISSUED 327 PM CST TUE JAN 30 2007/ SHORT TERM... UPPER LEVEL CLOUDS WERE REDEVELOPING FROM THE WEST WITH UPSLOPE FLOW BEHIND COLD FRONT THIS AFTERNOON (AT LEAST SOUTH OF INTERSTATE 20). WATER VAPOR LOOP INDICATED UPPER LEVEL LOW WAS OVER SOUTHERN CALIFORNIA...WITH SOME LIFT INDICATED AHEAD OF THE SYSTEM OVER ARIZONA AND NEW MEXICO. MID LEVEL MOISTURE INCREASES LATE TONIGHT AS UPPER LEVEL LOW SHEARS OUT AND MOVES TOWARD THE REGION...AND RIDING OVER THE COLD FRONT. MAY SEE SOME LIGHT PRECIPITATION TOWARD MORNING. GFS FORECAST SOUNDING INDICATE THIS TO BE SNOW OR SNOW/RAIN MIXTURE IN THE BIG COUNTRY...IF IT OCCURS. DO NOT ANTICIPATED ACCUMULATIONS. WENT A LITTLE LOWER ON TEMPERATURES (FROM MAV GUIDANCE) ACROSS THE BIG COUNTRY WHERE IT MAY TAKE A LITTLE LONGER FOR CLOUD COVER TO COME IN TONIGHT. LONG TERM... BEST SHORTWAVE/LIFT COMES IN WEDNESDAY TONIGHT. TEMPERATURES PROFILES INDICATE THIS TO BE MAINLY RAIN...THROUGH ITS POSSIBLE SOME SLEET MAY OCCUR IN NORTHERN SECTIONS OF THE BIG COUNTRY. RAIN CHANCES TAPER OFF THURSDAY MORNING. NEXT COLD FRONT COMES IN ON FRIDAY...KEEPING TEMPERATURES ON THE COOL SIDE THIS WEEKEND. MOISTURE TOO SHALLOW FOR ANY SIGNIFICANT RAIN THIS WEEKEND...THOUGH CANT RULE OUT A SPRINKLE OR TWO. ECMWF DIFFER IN HANDLING ANOTHER COLD FRONT NEXT WEEK. ECMWF HAS COLD FRONT MONDAY...WHICH BUILDS IN VERY STRONGLY THROUGH TUESDAY. THE GFS PUSHES MOST OF THE COLD AIR TO THE EAST ON MONDAY...WITH ONLY A WEAKER COLD FRONT. IT THEN BRINGS WEST CENTRAL TEXAS IN SOUTHERLY WARM ADVECTION TUESDAY...BEFORE A SECOND STRONG COLD FRONT MOVES IN TUESDAY NIGHT. WILL GO WITH THE COLDER ECMWF SOLUTION FOR NOW...AS A LOT OF TIMES FRONT GETS CHANNELS AGAINST THE ROCKY MOUNTAINS. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 31 48 37 48 / 20 30 50 20 SAN ANGELO 34 51 40 55 / 20 20 50 20 JUNCTION 37 49 44 60 / 20 20 50 20 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/HUBER tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 1257 PM CST TUE JAN 30 2007 .DISCUSSION...SFC LOW OVER NWRN GULF CONTINUES TO MOVE AWAY WITH HIGH PRESSURE BUILDING INTO THE REGION. NRLY LLVL WINDS COMBINED WITH SW WINDS ALOFT MAINTAINING MOSTLY CLOUDY SKIES TODAY. SFC WINDS WILL VEER TO THE SE THEN S WED AS A SFC LOW MOVES OUT OF THE SIERRA MADRE ORIENTAL. THE APPROACHING LOW WILL COMBINE WITH INCREASED LLVL MOISTURE PRODUCE MOSTLY CLOUDY TO CLOUDY SKIES...SCHC POPS...AREAS OF FG AND PATCHY DZ. THIS PATTERN WILL CONTINUE UNTIL SFC LOW MOVES E ALLOWING DRIER AIR TO ADVECT INTO CWA ON NW WINDS. A SECONDARY FRONT PUSHES THROUGH SAT BEFORE STALLING ACROSS OR JUST S OF CWA. THE PROXIMITY OF THE FRONT WILL COMBINE WITH WEAK COASTAL TROUGHING TO PRODUCE CHC POPS AND DZ THROUGH THE WEEKEND. CONDITIONS IMPROVE EARLY NEXT WEEK AS UPPER LEVEL RIDGE BUILDS INTO THE REGION. && .MARINE...SURFACE WINDS AT BUOY020 HAVE TAKEN A JUMP IN THE LAST HOUR REACHING TO NEAR 14 KTS WHICH IS LIKELY DUE TO THE FORMATION OF THE MARINE SURFACE LOW OVER THE NORTHWESTERN GULF OF MEX. A BEST GUESS FOR THE LOCATION OF THE SURFACE LOW UTILIZING SURFACE OBS...BUOY DATA AND THE LATEST RUC MSL FIELDS SEEMS TO BE ABOUT HALFWAY BETWEEN BUOY019 AND BUOY002. THE CLOSE PROXIMITY OF THIS LOW WILL LIKELY TIGHTEN THE PGF OFFSHORE TO PUSH WINDS TO NEAR SCA LEVELS TONIGHT. THIS LOOKS REASONABLE AND WILL ISSUE AN SCA FOR THE OFFSHORE WATERS FOR THE EVENING AND OVERNIGHT HOURS. AS THIS SURFACE LOW MOVES FURTHER AWAY FROM THE LOWER TX COASTLINE...THE PGF WILL RELAX SOME TOMORROW ALLOWING THE WINDS AND SEAS TO WEAKEN INTO WEDNESDAY NIGHT AND EARLY THURSDAY. HOWEVER...ANOTHER PUSH OF STRONGER NORTHERLY SURFACE WINDS WILL BEGIN LATE FRIDAY WITH STRONG NORTHEAST WINDS CONTINUING INTO SAT AND SUN. THE PGF WILL WEAKEN ONCE AGAIN ACROSS THE AREA ON MON INTO TUES AS THE CENTER OF THE STRONG SURFACE HIGH OVER THE EASTERN U.S. LIFTS OUT TO THE EAST AND SURFACE TROFFING ACROSS THE GULF OF MEX DIMINISHES. GWW GUIDANCE KEEPS 2 TO 3 METER SWELLS IN PLACE FOR THE OFFSHORE AREAS LATE SAT AND SUN AND IN THE 1 TO 2 METER RANGE FOR MON AND TUES. THIS LOOKS REASONABLE AND IS PRETTY WELL REFLECTED IN THE CURRENT CWF WORDING. && .AVIATION...VSBL SATELLITE IMAGERY SHOWS PRETTY EXTENSIVE AND THICK LOW LEVEL SC IN PLACE OVER THE REGION. ACCORDINGLY...LOW CEILINGS WILL LIKELY HOLD ON THROUGHOUT THE DAY. FWC/MAV AND MET VSBY GUIDANCE ALL INDICATE THAT FOG WILL LIKELY REFORM LATER TONIGHT WITH THE CONTINUED NORTHERLY SURFACE FLOW CONTINUING AND THE FAIRLY NARROW TEMP/DEWPOINT SPREADS PERSISTING INTO THE OVERNIGHT PERIOD. IFR/LIFR CONDITIONS WILL BE POSSIBLE AGAIN TONIGHT FOR ALL OF THE LOWER RGV AIRPORTS. INCREASED LOW LEVEL MIXING TOMORROW WILL GRADUALLY IMPROVE CEILINGS AND VSBYS ONCE AGAIN. HOWEVER...THE CEILINGS WILL LIKELY REMAIN SOMEWHAT LOW ONCE AGAIN ON WED. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 55 67 59 71 57 / 20 20 20 20 10 BROWNSVILLE 54 67 58 75 55 / 20 20 20 20 10 HARLINGEN 52 67 57 76 52 / 20 20 20 20 10 MCALLEN 53 64 56 75 53 / 20 20 20 20 10 RIO GRANDE CITY 53 61 53 76 52 / 20 20 20 10 10 SOUTH PADRE ISLAND 55 67 59 71 57 / 20 20 20 20 10 && .BRO WATCHES/WARNINGS/ADVISORIES... SCA GMZ 150-155-170-175 AFTER 6 PM CST. && $$ THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO 55/60/VEGA tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 430 AM EST THU FEB 01 2007 .SYNOPSIS... 07Z WATER VAPOR AND RUC ANALYSIS SHOWING A MUCH MORE ZONAL PATTERN ALONG THE EAST COAST AND DOWN TO THE GULF COAST. THIS WILL BE VERY SHORT LIVED AS ENERGY NOW DIVING THROUGH THE MID SECTION OF THE COUNTY WILL CONTINUE TO DIG SOUTH AND EAST AND AMPLIFY THE PATTERN THROUGH THE NEXT 24 TO 36 HOURS. AT THE SURFACE WE SEE HIGH PRESSURE BEGINNING TO SLIP OFF THE CAROLINA COAST AS LOW PRESSURE ORGANIZES IN THE WESTERN GULF OF MEXICO. A WARM FRONT EXTENDING EAST FROM THIS LOW IS NOW MOVING UP INTO THE CENTRAL AND NORTHEASTERN GULF OF MEXICO. THIS LOW WILL BE OUR WEATHER MAKER INTO EARLY FRIDAY MORNING. AS THE LOW HAS ORGANIZED OVERNIGHT PLENTY OF CLOUDS HAVE SPILLED EASTWARD OVER THE SOUTHEAST. AREAS OF PRECIPITATION HAVE ALSO BEEN ON THE MOVE TOWARD THE EAST AND NORTHEAST WITH THE MAIN THRUST OF THE PRECIP UP ACROSS MS/AL/AND NORTHERN GEORGIA SO FAR. ACROSS THESE AREAS THE COLD AIR IS MORE DEEPLY ENTRENCHED AND AREAS OF SLEET AND FREEZING RAIN HAVE BEEN OCCURRING. && .SHORT TERM... (TODAY-SATURDAY) LOW PRESSURE WILL CONTINUE TO DEVELOP ACROSS THE NORTH-CENTRAL GULF OF MEXICO TODAY WITH AREAS OF RAIN AND ISOLATED THUNDERSTORMS SPREADING EAST THROUGH THE DAY. THE EASTERN PORTION OF THE CWA IS LIKELY TO BE INITIALLY FAIRLY DRY WITH THE EXCEPTION OF A FEW WIDELY SCATTERED SHOWERS AND HAVE LOWERED POPS FOR THE FIRST HALF OF THE DAY. AREAS OF RAIN WILL THEN OVERSPREAD THE ENTIRE AREA THROUGH THE AFTERNOON AS THE LOW AND BETTER DYNAMICS APPROACH. SO FAR THE BEST ISENTROPIC LIFT HAS REMAINED TO OUR NORTH WHERE AREAS OF RAIN/FREEZING RAIN/SLEET AND SNOW HAVE BEEN WIDESPREAD THIS OVERNIGHT. WITH THE FORECAST LOW TRACK...THE WARMFRONT IS NOT LIKELY TO PENETRATE INLAND VERY RAPIDLY. HIGH TEMPERATURES IN THE MIDDLE TO UPPER 50S ACROSS OUR NORTHERN ZONES WILL LIKELY NOT BE REALIZED UNTIL LATE IN THE DAY WITH COOL CONDITIONS BEING EXPERIENCE IN THESE AREAS NORTH OF THE WARM FRONT. SPC CONTINUES TO COVER PORTIONS OF NORTH FLORIDA INTO FAR SOUTHERN GEORGIA WITH A SLIGHT RISK OF SEVERE WEATHER THIS AFTERNOON INTO THE EVENING. AT THIS TIME THINK ANY SEVERE WEATHER LOOKS TO BE ISOLATED IN NATURE...BUT SHEAR PROFILES DO INDICATE THAT ANY SURFACE BASED STORMS THAT GET GOING IN THE WARM SECTOR WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS AND ISOLATED TORNADOES. WILL CONTINUE TO WATCH THE SITUATION AND HAVE HIGHLIGHTED THE SEVERE THREAT IN THE GRIDS AND HWO. COLD FRONT WILL CROSS THE REGION OVERNIGHT BRINGING A END TO THE SEVERE THREAT FROM WEST TO EAST. FRONT AND QPF FIELDS SHOULD CLEAR OUR AREA BY LATE MORNING ALTHOUGH CLOUDS MAY BE A BIT MORE STUBBORN... ESPECIALLY ACROSS THE FLORIDA BIG BEND. FURTHER WEST AND NORTH WILL EXPECT AT LEAST SOME SUN BY THE AFTERNOON. HIGH TEMPERATURES WILL BE NEAR OR SLIGHTLY BELOW NORMAL FRIDAY AFTERNOON WITH MAINLY UPPER 50S TO MIDDLE 60S AS THERE IS NOT A SIGNIFICANT COOL PUSH BEHIND THIS SYSTEM. HIGH PRESSURE CONTINUE TO BUILD EAST ALONG THE GULF COAST FRIDAY NIGHT INTO SATURDAY. THIS IS WHERE THE FORECAST BECOME A BIT TRICKY. GUIDANCE IS SHOWING THE FRONT TO OUR SOUTH MAKING SOME HEADWAY BACK NORTH WITH A BAND OF ISENTROPIC LIFT ON THE 295-300K SURFACES TRYING TO GET BACK UP INTO OUR AREA. THE NAM IS MUCH MORE AGGRESSIVE WITH THIS FEATURE AND SPREADS WIDESPREAD QPF BACK OVER THE ENTIRE FORECAST AREA SATURDAY AND SATURDAY NIGHT. THE GFS IS SHOWING THE HIGH TO OUR WEST NOSING IN SIGNIFICANTLY MORE AND HOLDING MUCH OF THIS LIFT AND MOISTURE INTO NORTH FLORIDA AND THE NORTHEASTERN GULF. THE GFS HAS STRONG SUPPORT FROM BOTH THE ECMWF AND UKMET ON THIS SCENARIO. DISCUSSIONS WITH SURROUNDING OFFICES AND HPC SHOW AN AGREEMENT THAT THIS MORE SUPPRESSED SOLUTION IS THE BETTER WAY TO GO AND HAVE DRAWN MY POP GRIDS TO REPRESENT. ONLY HAVE SLIGHT TO LOW END CHANCE POPS FOR SHOWERS OVER THE NORTH WITH MID TO HIGH CHANCE POPS OVER NORTH FLORIDA SAT/SAT NIGHT. AS WAS MENTIONED LAST NIGHT THIS IS A RATHER COOL AIRMASS TRYING TO COME IN SATURDAY NIGHT AND A FEW FLAKES OF SNOW OR A FEW ICE PELLETS CAN NOT BE RULED OUT OVER PORTIONS OF THE AREAS SAT NIGHT...BUT STILL BELIEVE THE QPF WILL EXIT AHEAD OF THE REAL COOL AIR PUSH. EITHER WAY ANY FROZEN PRECIP WOULD BE LIGHT AND NOT AMOUNT TO MUCH OF ANYTHING...WILL CONTINUE TO WATCH. .LONG TERM... (SUNDAY-THURSDAY) ANY LINGERING SHOWERS WILL EXIT SOUTH OF THE AREA EARLY SUNDAY MORNING. AS IT LOOKS NOW AN EXTENDED PERIOD OF DRY AND COOL WEATHER WILL THEN BE WITH US INTO THE MIDDLE PART OF NEXT WEEK. BOTH GFS/ECMWF SHOWING HIGH PRESSURE OVER THE REGION BY SUNDAY EVENING INTO MONDAY. THIS HIGH THEN BRIEFLY WEAKENS MONDAY NIGHT BEFORE A STRONGER AND MORE DOMINANT HIGH BUILDS JUST NORTH OF THE AREA FOR TUESDAY INTO THURSDAY. THIS HIGH IS LIKELY TO BRING WITH IT PLENTY OF COOL AND DRY AIR ON NORTHERLY TO NORTHEASTERLY FLOW. AT THIS TIME THE POSITION OF THE HIGH WOULD BE TO FAR NORTH TO ALLOW ANY NIGHTS OF SIGNIFICANT RADIATIONAL COOLING...BUT THIS IS QUITE A WAY INTO THE FUTURE FOR DETAILS. && .AVIATION... LOCAL RADARS AND AIRPORT OBSERVATIONS SHOW THAT SO FAR THE LOWER ATMOSPHERE IS TOO DRY TO ALLOW THE LIGHT RAIN TO FALL TO THE SURFACE. WE EXPECT THESE CONDITIONS TO PERSIST THROUGH THE OVERNIGHT AND EARLY MORNING HOURS. IT APPEARS THAT THE BEST CHANCE FOR RAIN WILL BE THIS AFTERNOON...EARLY AFTERNOON FOR KDHN AND KPFN...AND MID TO LATE AFTERNOON FOR KTLH...KABY...AND KVLD. OCCASIONAL THUNDER IS EXPECTED...MAINLY AT KPFN...KTLH...AND KVLD...WHERE THE INSTABILITY IS GREATER. VFR CEILINGS ARE FORECAST FOR THE OVERNIGHT HOURS...BUT THE CEILINGS WILL GRADUALLY LOWER TO MVFR (AROUND 2500 FT) THIS MORNING AND REMAIN MVFR THROUGHOUT THE DAY. THE VISIBILITY WILL ALSO BE REDUCED TO MVFR IN AREAS OF MODERATE RAIN...BUT LOCAL IFR CONDITIONS ARE POSSIBLE IN THE HEAVIER SHOWERS. WE THINK THE HEAVIEST RAIN WILL GRADUALLY DIMINISH FROM WEST TO EAST THIS EVENING...FOLLOWED BY A LONGER PERIOD OF MOSTLY LIGHT RAIN UNTIL ABOUT 06 UTC. && .MARINE... LOW PRESSURE DEVELOPING IN THE CENTRAL GULF OF MEXICO WILL MOVE NORTHEAST TODAY PASSING NORTH OF THE COASTAL WATERS TONIGHT. WIND AND SEAS HAVE INCREASED TO SMALL CRAFT ADVISORY LEVELS AND WILL CONTINUE ELEVATED THROUGH TONIGHT. WINDS INITIALLY OUT OF THE SOUTHEAST WILL COME AROUND TO SOUTHWEST BY THIS EVENING. NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THIS EVENING WITH A FEW OF THE STORMS REACHING SEVERE LIMITS. COLD FRONT WILL CROSS THE WATERS TONIGHT WITH WINDS COMING AROUND TO THE NORTHWEST AND DECREASING BELOW ADVISORY LEVELS. HIGH PRESSURE THEN BUILDS ACROSS THE WATERS THROUGH FRIDAY NIGHT. THE GRADIENT WILL INCREASE AGAIN FROM SATURDAY THROUGH MONDAY WITH NEAR CAUTION LEVEL WINDS AND SEAS...ESPECIALLY ACROSS THE OFFSHORE LEGS. && .FIRE WEATHER... A LOW PRESSURE SYSTEM AND ASSOCIATED FRONT WILL MOVE EAST ACROSS THE SOUTHEAST U.S. TODAY AND TONIGHT...BRINGING WITH IT WIDESPREAD RAIN TO THE REGION. THE RAIN WILL GRADUALLY END FROM NORTHWEST TO SOUTHEAST LATE TONIGHT AND EARLY FRIDAY AS A COLD FRONT MOVES SOUTH INTO THE GULF. THIS FRONT WILL STALL ACROSS THE GULF THIS WEEKEND...BRINGING A BRIEF RETURN OF RAIN CHANCES UNTIL SUNDAY AFTERNOON...WHEN ANOTHER PUSH OF DRY AIR FORCES THE CLOUDS AND SHOWERS FAR DOWN INTO THE GULF. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 65 54 64 45 53 / 90 90 20 20 50 PANAMA CITY 65 54 62 45 55 / 90 90 10 20 50 DOTHAN 59 48 60 39 53 / 90 80 10 10 30 ALBANY 57 49 62 40 52 / 90 90 10 10 30 VALDOSTA 64 54 65 45 54 / 80 90 20 20 40 CROSS CITY 69 62 69 49 60 / 60 90 40 30 50 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...SMALL CRAFT ADVISORY IN EFFECT ALL ZONES THROUGH 7 AM EST /6 AM CST/ FRIDAY MORNING. && $$ AVIATION...FOURNIER REST OF DISCUSSION...MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 330 AM CST THU FEB 1 2007 .SYNOPSIS... COLD FRONT WAS JUST ENTERING NWRN CWA EARLY THIS MORNING. NARROW BAND OF LIGHT...ACCUMULATING...SNOW AHEAD OF THE FRONT WAS STILL OVER THE FAR EASTERN COUNTIES EARLY THIS MORNING WITH SCATTERED FLURRIES EXTENDING BACK TO THE WEST. LOW CLOUDS HAVE SCATTERED OUT CONSIDERABLY WEST OF THE MISSISSIPPI RIVER AND NORTH OF I80 WITH DEFINITE CLEARING LINE FROM KMCW TO JUST WEST OF KDSM AT 09Z. LITTLE CHANGE WAS NOTED IN THE UPPER AIR PATTERN FROM THE LAST SEVERAL DAYS. REGION REMAINS UNDER BROAD MID LEVEL TROF WITH SHARP H5 RIDGE ANCHORED JUST OFF THE WEST COAST. S/W TROF ASSOCIATED WITH THE COLD FRONT OVER THE REGION THIS MORNING...EXTENDED FROM MN SW THROUGH WRN NE AT 00Z. ANOTHER POTENT S/W WAS LOCATED UPSTREAM OVER NRN SASKATCHEWAN AND ALBERTA. && .SHORT TERM...TODAY AND TONIGHT... SHORT RANGE MODELS ARE IN GOOD AGREEMENT WITH RAPID SUCCESSION OF FRONTS MOVING THROUGH THE CWA TODAY AND TONIGHT. FRONT CURRENTLY CROSSING CWA SHOULD BE EAST OF THE AREA THIS MORNING WITH ASSOCIATED S/W TROF REACHING THE MS RIVER BY MIDDAY. WEAK SURFACE RIDGE TO CROSS CWA THIS AFTERNOON...THEN RETURN FLOW DEVELOPS FOR BRIEF TIME THIS EVENING INTO EARLY FRIDAY MORNING. NEXT S/W DROPS INTO WRN IA BY 12Z FRIDAY WITH SURFACE COLD FRONT PROGGED TO BE JUST WEST OF THE MS RIVER. INITIAL CHALLENGE WILL CONCERN CLOUD TRENDS TODAY WITH BACK OF EDGE OF LOW CLOUDS ALREADY INTO CENTRAL IA...WELL EAST OF NAM/GFS SHOW BACK EDGE OF LOW LEVEL RH THIS MORNING. BASED ON CURRENT TRENDS AND MORE REALISTIC 925 RH PROGS OFF THE RUC...HAVE DECREASED SKY COVER OVER CWA CONSIDERABLY THIS MORNING...BEFORE HIGH CLOUDS AHEAD OF NEXT S/W SWEEP OVER CWA THIS AFTERNOON. MAX TEMPS TODAY OFFER ANOTHER CHALLENGE WITH LESS CLOUDS THAN MOS SHOWS FAVORING WARMER TEMPS. HOWEVER LIGHT WINDS IN SURFACE RIDGE AND FRESH DUSTING OF NEW SNOW ALONG WITH LOW LEVEL CAA MOST OF THE DAY POINTING TO COLDER TEMPS SHOULD OFFSET ANY ADDITIONAL SUN. KEPT MAX TEMPS AT OR JUST BELOW COLDER MET GUIDANCE. NEXT S/W PROGGED TO MOVE THROUGH CWA BY FRIDAY. QVECTOR CONVERGENCE SUGGESTS BEST SYNOPTIC FORCING AHEAD OF TROF WILL STAY TO OUR NORTH...SO KEPT LOW CHANCE POPS GOING FOR TONIGHT. SURFACE FRONT SHOULD BE ENTERING NORTHWEST CWA AFTER 09Z WITH STRONG NW WINDS KICKING RIGHT AFTER FROPA. WITH HALF INCH TO INCH OF FLUFF THAT FELL WEDNESDAY EVENING ...FELT THAT BLSN CURRENTLY IN GRIDS WAS WORTH KEEPING. ..DLF.. .LONGER TERM...FRIDAY THROUGH NEXT WEDNESDAY...A RATHER VIGOROUS VORT COMPLEX NOW SEEN ON W/V IMAGERY WEST OF HUDSON BAY...IS STILL PROGGED BY LATEST SUITE OF SHORT RANGE MODEL RUNS TO ROTATE DOWN ACRS THE AREA IN STEEPENING CYCLONIC UPPER FLOW ON FRI AS POLAR VORTEX BECOMES ENTRENCHED OVER WESTERN ONTARIO. LOW TO MID LEVEL SATURATION FOR MUCH OF ANYTHING TO GET WRUNG OUT BY THE INCOMING LIFT OTHER THAN SOME FLURRIES STILL AT QUESTION...BUT LATEST FCST PROFILES/SOUNDINGS SHOW ENOUGH FOR MORE OF A LIGHT SNOW AS OPPOSED TO SPORADIC FLURRIES THROUGH AT LEAST MIDDAY ACRS THE NORTHEAST 2/3`S OF THE FCST AREA. WITH EXPECTED MOMENTUM WIND SURGE/ABOVE THAT ADVERTISED BY THE MODELS/ BEHIND FROPA AS ARCTIC FRONT PLOWS ITS WAY THRU AND EAST OF THE AREA FRI MORNING...SOME BLOWING OF THE POWDER/ THAT COULD ACCUMULATE FROM .5 TO AN INCH BY LATE FRI MORNING/ ACRS ROADS AND OPEN FIELDS WILL BE LIKELY AND WILL INCLUDE WORDING FOR THIS IN THE GRIDS. AS FOR TEMPS...MAYBE A FEW DEGREES RECOVER FROM 12Z VALUES DURING LATE FRI MORNING AND MIDDAY...BUT EXPECT A THERMAL DROP OFF AS THE AFTERNOON PROGRESSES AS YET ANOTHER -20 C AND COLDER H85 MB COLD POOL SEEPS RIGHT OVER THE FCST AREA. WIND CHILLS DURING THE DAY DIP INTO THE MID TO UPPER TEENS BELOW ZERO FOR AWHILE IN THE NORTHWESTERN CWA...BUT DON/T QUITE REACH ADVISORY CRITERIA. THAT WILL CHANGE BY FRI NIGHT AS WINDS AND STOUT CAA MAINTAIN. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED LATER FRI NIGHT AND INTO SAT FOR MUCH OF THE DVN CWA. AS FOR ANOTHER CLIPPER SKIRTING DOWN ACRS THE AREA FRI NIGHT...THE GFS IS AGAIN THE MOST BULLISH WITH LIFT AND SATURATION AND LOOKS OVERDONE...BUT WILL KEEP CHC POPS FOR LIGHT SNOW AFTER MIDNIGHT AND INTO EARLY SAT MORNING. OTHERWISE OCCASIONAL FLURRIES WILL ACCOMPANY AND CLOUD COVER THAT SWEEPS ON THRU IN STEEP NORTHWEST FLOW WITH ANY SATURATION EASILY IN THE -10 C OR COLDER RANGE. 3RD NIGHT IN A ROW WHERE LATEST RUN AND ACCEPTED/FAVORED MEDIUM RANGE MODEL RUNS ADVERTISE MERIDIONAL FETCH FROM NORTHWEST OF THE HUDSON BAY REGION- ARCTIC BRINGING NEAR -30 C H85 COLD POOL DOWN NEAR THE FCST AREA SAT NIGHT INTO SUN. WILL CONTINUE TO MAKE MINOR TWEAKS/DOWN TRENDS IN BOTH HIGHS AND LOWS OVER THE WEEKEND...WITH THE CONTINUING THOUGHT OF AT LEAST SOME -20 F VALUES BEING REACHED IN PORTIONS OF THE FCST AREA EITHER SUNDAY MORNING OR MONDAY LOOKING ON TARGET. ONLY WEAKENING SFC WINDS WITH SOME LLVL RIDGING MAKING ITS WAY ACRS THE AREA LATER SAT NIGHT INTO SUNDAY MAY PRECLUDE A WIND CHILL WARNING FOR THAT TIME PERIOD...BUT STILL NOT OUT OF THE QUESTION. NO CHANGES INTO EARLY NEXT WEEK FOR NOW. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ DLF/12 ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1210 AM EST THU FEB 01 2007 .AVIATION DISCUSSION (06Z) TAFS... CEILINGS WILL LOWER TO MVFR CONDITIONS BY 10Z ACROSS ALL OF THE TAF SITES AS AN AREA OF LIGHT SNOW ARRIVES. LIGHT SNOW...WITH VISIBILITIES GENERALLY REMAINING AROUND 2SM OR ABOVE WILL BEGIN AT BWG AFTER 6Z...SDF FROM 08-10Z AND AT LEX AND BWG AROUND 09-11Z. CEILINGS IN THE SNOW WILL FALL TO 2-3 THOUSAND FEET. SURFACE WINDS WILL REMAIN LIGHT OVERNIGHT WITH 20 KT SW FLOW AT AROUND 2000 FEET. LIGHT SNOW WILL CHANGE TO FLURRIES BY MID MORNING WITH ACCUMULATIONS REMAINING AT OR BELOW 1 INCH...BUT CEILINGS WILL REMAIN MVFR THROUGHOUT TODAY. ANOTHER ROUND OF LIGHT SNOW IS EXPECTED AFTER 00Z FRIDAY. JSD && .EVENING UPDATE (WEDS EVENING 9 PM) LATEST IR SATELLITE LOOP IS SHOWING SOME ENHANCEMENT IN THE CLOUD ELEMENTS OVER CENTRAL AND NORTHERN AR AND NRN AL ...LOOKING AT THE RADAR TRENDS THAT AREA...THEY ARE SHOWING SOME INCREASE IN COVERAGE TOO. BOTH THE CLOUDS AND PCPN ARE MOVING TO THE NORTHEAST TOWARDS SRN KY. A PRELIMINARY LOOK AT THE NEW 00Z NAM MODEL DATA IS NOT AS PROMISING FOR SNOWFALL. THE AIR ALOFT WAS INITIALLY QUITE DRY TODAY AND IF THE AIR DOESN`T BECOME SUFFICIENTLY SATURATED IN THE LOWER LEVELS... ANY PRECIP THAT DOES FALL WILL EVAPORATE BEFORE REACHING THE GROUND. THE 18Z GFS DID SHOW SUFFICIENT SATURATION AND ENOUGH SYNOPTIC LIFT FOR AN INCH OR TWO OF SNOWFALL ESPECIALLY DURING THE 10Z-18Z TIME FRAME ACROSS PORTIONS OF SOUTHERN KENTUCKY. THIS MATCHES WELL WITH OUR SNOW ADVISORY ACROSS THE SOUTHERN PORTION OF THE FA. THE LATEST RUC40 RH TRENDS SHOW A MAJOR INCREASE IN LOW LEVEL RH SW TO NE ACROSS MOST OF THE REGION OVERNIGHT...THIS TOO WUD SUPPORT THE POTENTIAL FOR MEASURABLE SNOW LATER TONIGHT. BEFORE MAKING ANY MAJOR CHANGES...WE NEED TO LOOK AT THE FULL SUITE OF 00Z MODEL RUNS...PLUS CHECK WITH THE NEXT HPC SNOW FCSTS AND CONSIDER THEIR ANALYSIS TOO. COORDINATED WITH JKL AND THEY WERE PLANNING TO LEAVE THEIR ADVISORY INTACT. AT THIS TIME WE ARE NOT MAKING ANY CHANGES IN THE CURRENT FCST. --21 ....PREVIOUS FCST DISCUSSIONS FOR TODAY ARE BELOW:... .SHORT TERM... (TONIGHT THROUGH THURSDAY NIGHT)... ...SNOW ADVISORY ACROSS SOUTHERN KY AND SOUTHERN BLUEGRASS... SHORT-TERM FORECAST REVOLVES AROUND SOUTHERN STREAM SYSTEMS AND SNOW ACCUMULATION CHANCES WITH EACH. TONIGHT-MIDDAY THURS... HIGH PRESSURE OVERHEAD WILL MOVE OFF TO THE EAST TONIGHT...AS AN INVERTED TROUGH OVER THE GULF MOVES FROM TEXAS TOWARD THE CAROLINAS. MOISTURE IS NOT TOO IMPRESSIVE WITH THIS SYSTEM...HOWEVER THE DYNAMICS ARE STRONG. SOUTHERN JET OF ROUGHLY 150 KTS OR SO WILL BE OVERHEAD...WITH THE CWA UNDER THE LEFT-EXIT REGION AFTER MIDNIGHT. AMPLE LIFT WILL THUS HELP SNOW DEVELOP AFTER MIDNIGHT TOWARD MORNING. AREA SOUNDINGS INDICATE THE BEST CHANCE OF SNOW WILL BE BETWEEN 10-17Z. SOME HEAVIER SNOW MAY MIX IN AT TIMES GIVEN UPSTREAM REPORTS AND PROGGED -EPV ALOFT CO-LOCATED WITH MAX OMEGAS. BUT GIVEN THE LACK OF MOISTURE AND SPEED OF SYSTEM...WILL NOT GET CARRIED AWAY WITH SNOW AMOUNTS. THUS...WILL ISSUE A SNOW ADVSY FROM 1-2 INCHES POSSIBLE MAINLY SE OF A LINE FROM MORGANTOWN TO LEBANON. MAY BE A BIT TOO FAR NORTH WITH THE ADVY GIVEN THE NAM 18Z RUN...BUT 12Z GFS/NAM AND HPC INDICATE FAR SRN KY COULD GET THESE ACCUMULATING SNOWS. THE BIGGER PROBLEM WILL BE TIMING NOT THE ACTUAL ACCUMS. GIVEN TIME OF DAY (NEAR MORNING COMMUTE TIME) FELT IT WAS WORTH BUMPING UP THE SPS TO AN ADVSY. WILL KEEP THE HIGHER SNOW AMOUNTS ACROSS THE FAR SERN CWA. ELSEWHERE...WILL CONTINUE SPS FOR AROUND AN INCH OF ACCUMULATION. FEEL THAT THE THREAT IS MINIMIZED ACROSS CENTRAL KY...HOWEVER A BETTER CHANCE MAY EXIST NEAR THE OHIO RIVER WITH THE DEFORMATION ZONE DEVELOPING FROM KC TO WICHITA. THIS SHOULD ALIGN SOMEWHERE ACROSS OUR NRN CWA...POSSIBLY NEAR THE KY/IN BORDER. SNOWFALL AMOUNTS WITHIN THE SPS AREA WILL BE HIGHER IN THE DEFORMATION ZONE...BUT IT IS STILL EXPECTED TO BE LIGHT SNOW ONLY. MAIN PRECIP WILL END BY MIDDAY (ADVY ENDS AT 18Z)...THOUGH LOW CLOUDS MAY CONTINUE THROUGH THE AFTERNOON. WITH THIS...EVEN A FEW LIGHT SHOWERS/FLURRIES MAY CONTINUE INTO THE AFTERNOON HOURS. SFC TEMPS MAY INCREASE ENOUGH ACROSS THE SOUTH WHERE A CHANGEOVER TO LIGHT RAIN/DRIZZLE MAY OCCUR. HAVE A RAIN/SNOW MIX ACROSS THE SOUTH FOR NOW. MIDDAY THURS-OVERNIGHT THURS... SECOND WAVE IN SOUTHERN STREAM WILL QUICKLY MOVE TOWARD THE EAST COAST RIGHT ON THE HEELS OF THE FIRST SYSTEM. THIS SYSTEM IS MORE OF A CLOSED SFC LOW AS OPPOSED TO A SFC TROUGH...AND IS COMBINED WITH EVEN STRONGER DYNAMICS ALOFT. HOWEVER MOISTURE IS EVEN MORE LACKING...BUT THE DYNAMICS ARE THERE FOR YET ANOTHER POSSIBLE ADVSY SITUATION THRS NIGHT-FRI MORN. WILL LOOK MORE AT IT TONIGHT AND TOMORROW MORNING...BUT WILL HIT IT HARD IN THE HWO. THIS LATTER SYSTEM WOULD BE MORE OF A CWA-WIDE EVENT TOO. WILL CONTINUE WITH ONE-INCH ACCUMS FOR NOW. AS FAR AS TEMPS GO THROUGH THE PERIOD...WILL ONLY DROP ABOUT 5 DEGREES TONIGHT BEFORE CLOUDS INCREASE OVERNIGHT AND KEEP OUR TEMPS STEADY. TOMORROW...WILL LIKELY HEAT UP...ESPECIALLY IN THE AFTERNOON. HOWEVER WILL UNDERCUT RUC13/GFS AS I FEEL THESE ARE RUNNING A BIT TOO HIGH. LOW TO MID 30S LOOK LIKELY FOR HIGHS THURS. AL .LONG TERM (FRI THRU WED)... FRI THRU SAT NGT... SHRTWV TROF WILL BE DROPPING DOWN INTO THE UPR MS VLY/WRN GREAT LAKES AT THE START OF THE PERIOD WITH MORE ENERGY ROUNDING THE BASE OF THE UPR LEVEL BROAD TROF TOWARD THE LOWER MS VLY. THIS ELONGATED AXIS OF HIER VORTICITY BECOMES INCREASINGLY SHEARED AS IT MOVES THRU OUR FA FRI WITH AFOREMENTIONED SHRTWV MOVG WELL TO OUR NORTH...ACRS THE GREAT LAKES. AFTERWARD...WE REMAIN IN A BROAD TROF THRU THE END OF THE PERIOD WITH ANOTHER IMPLSE APPROACHING OUR FA SAT NIGHT. ASSOCIATED CDFNT WILL MOVE THRU FRI...WITH A RIDGE OF HI PRES IN ITS WAKE FOR FRI NIGHT AND MUCH OF SAT. WILL CONTINUE CHC POPS FOR LIGHT SNOW PRECEDING FRONT...MAINLY IN THE FIRST HALF OF THE DAY. A REINFORCING SHOT OF COLD AIR...ASSOCIATED WITH AFOREMENTIONED IMPULSE...WILL LIKELY MOVE THRU OUR FA SAT NIGHT. WILL DOWNPLAY THE NAM/WRF DEEPER MOISTURE PRECEDING AND WITH FRONT AND CONT A PARTLY CLOUDY FCST...CLOSER TO THE GFS. 11 SUN THRU WED... VERY COLD AND MAINLY DRY THRU THIS PERIOD. BROAD UPR LEVEL TROF WILL RESIDE ACRS THE OH VLY THRU LATE MON WITH AXIS SHIFTING INTO NEW ENGLAND TUE AND OFF THE NEW ENGLAND COAST WED. AFTER AXIS PASSAGE MON...OUR REGION WILL BE IN COLD NW FLO THRU THE END OF THE PERIOD. 00Z MEDIUM RANGE MODELS AND 12Z GFS ARE SIMILAR WITH SHOWING A FAST MOVG CLIPPER SYS/WEAK SFC LO MOVING INTO THE LOWER OH VLY SUN NGT AND EXITING MON MORNING. THIS APPEARS TO BE OUR BEST CHC FOR A MEASURABLE SNOW DURING THIS PERIOD WITH POSSIBLY A 1 TO 3 INCH DRY FLUFFY SNOW ACRS OUR FORECAST AREA(FA)...MOSTLY OVER OUR NRN/ERN FA. TEMPS WILL BE UNSEASONALLY COLD...ESPECIALLY AFTER CLIPPER PASSAGE MON WITH SINGLE DIGIT READINGS MON AND TUE NGT AS ARCTIC HI PRES BUILDS INTO AND OVER THE LOWER OH VLY. AFTER POPULATING WITH HPC GRIDS FOR TUE AND WED...WILL MAKE THE FOLLOWING CHGS TO TEMP GRIDS. WILL RAISE SUN NGT MINS CONSIDERABLY TO ACCOUNT FOR INCREASING CLOUDS/A BRIEF PERIOD OF WARM ADVECTION AHEAD OF CLIPPER. WILL RAISE MAXS MON A FEW DEGREES CLOSER TO ENSEMBLE MEANS AND HPC AND TO AGREE BETTER WITH OUR NEIGHBORS. IF WE GET AN INCH OR TWO OF SNOW COVER BEFORE THIS PERIOD AND ON SUN NGT AS WELL...THESE TEMPS WILL NEED TO BE ADJUSTED DOWN...IN OTHER WORDS...BELOW ZERO FOR MINS BEGINNING MON NGT. DK && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 5 AM EST /4 AM CST/ TO 1 PM EST /12 PM CST/ THURSDAY FOR KYZ062>066-070>078-081-082. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1152 PM EST WED JAN 31 2007 .AVIATION... EXAMINATION OF AVAILABLE 00Z MODEL RUNS REVEALS GOOD CONTINUITY WITH THE DAYTIME/18Z RUNS. MID AND HIGH CLOUDS EXPECTED TO PREVAIL FOR MOST OF THE NIGHT...WITH THE MID CLOUDS CURRENTLY THICKENING/LOWERING WITH TIME IN AGREEMENT WITH MODEL SOUNDINGS AND MOISTURE TIME SECTIONS. BY 09Z AT KMBS AND EARLY FORENOON AT THE OTHER TAF SITES...EXPECT LOWERING CEILINGS INTO MVFR AS DEARTH OF LOW LEVEL MOISTURE ENDS...WITH THE NORTH AIDED BY TRAJECTORY OFF OF LAKE MICHIGAN. NEARLY ADIABATIC LOW LEVEL LAPSE RATES DEVELOPING THURSDAY AS COLD TEMPERATURES ALOFT PROMOTE EXPECTED DIURNAL BOOST FOR SNOW SHOWERS. TAFS WILL CONTINUE A PROB30 GROUP BETWEEN 17Z TO 21Z OR 18Z TO 22Z FOR MVFR VISIBILITIES IN SNOW SHOWERS. NOT ENOUGH CONFIDENCE IN POTENTIAL OVERNIGHT TO MENTION ANY VISIBILITY RESTRICTING SNOWFALL...AS LOW LEVEL MOISTURE WILL BE SPARSE. MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE LOTS OF LOW LEVEL MOISTURE/CLOUDS THURSDAY EVENING...THOUGH WITH LOSS OF DIURNAL INFLUENCES WILL NOT MENTION ANY VISIBILITY RESTRICTIONS. && .PREV DISCUSSION...ISSUED 434 PM EST WED JAN 31 2007 SHORT TERM...TONIGHT AND THURSDAY OVERNIGHT LOWS LIKELY TO OCCUR SHORTLY AFTER SUNSET...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE AREA WHERE CURRENT TEMPS REMAIN IN THE TEENS...15 AT ADRIAN. THUS...LOWEST OVERNIGHT LOWS ARE EXPECTED IN THAT AREA. THEN TEMPS ARE EXPECTED TO LEVEL OFF AND POSSIBLY CLIMB A LITTLE OVERNIGHT UNDER A WEAK WARM AIR ADVECTION REGIME. THE POTENTIAL FOR SCATTERED LIGHT SNOW SHOWERS ARRIVES AFTER MIDNIGHT AND WILL EXIST THROUGH THURSDAY. LIMITED MOISTURE AND A WEAKENING SYSTEM WILL KEEP SNOW SHOWERS ON THE LIGHT SIDE WITH LITTLE TO NO ACCUMULATION EXPECTED. THE SAGINAW VALLEY STANDS TO SEE THE BEST ACTIVITY AS THAT IS THE FAVORED AREA FOR LAKE LAKE ENHANCED SNOW SHOWERS WITHIN SOUTHWESTERLY FLOW REGIME. LATEST RUC ANALYSIS/SATELLITE DATA SUPPORTS THE MODELS CONSISTENT FORECAST OF THE SHORT WAVE SHEARING OUT WITHIN CONFLUENT FLOW ALOFT OVER THE GREAT LAKES EARLY THURSDAY MORNING. UPPER DIVERGENCE...WITHIN RIGHT ENTRANCE REGION OF DEPARTING JET STREAK... WILL BE SUPPORTIVE OF EXTRA LIFT OVERNIGHT...MAINLY ACROSS THE NORTH HALF OF THE CWA. MODEL SOUNDINGS INDICATE THAT THE VERY DRY 900 TO 700 MB COLUMN OF AIR WILL THEN MOISTEN UP CONSIDERABLY DURING THE EARLY MORNING HOURS. BUT WITH VERY LITTLE INSTABILITY AND LACK OF LOW LEVEL SUPPORT...ANY SNOW SHOWERS SHOULD REMAIN ON THE TAME SIDE. BY THE TIME BETTER LOW LEVEL SUPPORT ARRIVES ON THURSDAY...THE MID AND UPPER LEVEL MOISTURE WILL BEGIN TO STRIP AWAY AS THE UPPER SUPPORT BECOMES SHEARED OUT. HOWEVER WITH INVERSION HEIGHTS AROUND 800 MB ON THURSDAY NORTH OF DETROIT...LINGERING SNOW SHOWERS CANNOT BE RULED OUT. LONG TERM... THE PLAINS WAVE WILL HAVE SHEARED TO OUR EAST BY THURSDAY NIGHT LEAVING ONLY A CHANCE OF LIGHT SNOW SHOWERS OR FLURRIES UNTIL THE NEXT SYSTEM ARRIVES FROM CENTRAL CANADA ON FRIDAY. THIS FEATURE LOOKS TO BE HANDLED WELL JUDGING FROM SATELLITE IMAGERY TODAY BUT IT IS HARD TO GET EXCITED ABOUT THE PROSPECTS FOR SNOW AS IT MOVES THROUGH OUR AREA FRIDAY AFTERNOON. MID LEVEL MOISTURE WILL BE AT A PREMIUM AS THE WAVE WILL BE CUT OFF FROM BOTH GULF AND PACIFIC MOISTURE SOURCES. HOWEVER, A BOOST FROM LAKE MICHIGAN LOOKS REASONABLE AS THE COLD FRONT MOVES THROUGH LOWER MICHIGAN FRIDAY AFTERNOON AND EVENING. THIS IS WORTH CHANCE/SCATTERED POPS FOR SNOW SHOWERS. OUR FIRST SURGE OF ARCTIC AIR WILL ARRIVE BEHIND THIS SYSTEM FRIDAY NIGHT. THE 12Z MODELS ALL SHOW 850 MB TEMPS DROPPING TO AROUND -20C BY SUNRISE SATURDAY MORNING. A SW COMPONENT TO THE WIND WILL INITIALLY HELP WITH SINGLE DIGIT LOW TEMPERATURES, DESPITE SOME CLOUD COVER, AS COLDER SURFACE AIR FLOWS AROUND THE SOUTH END OF LAKE MICHIGAN AND INTO OUR AREA. HOWEVER, THIS SAME SW FLOW WILL STRENGTHEN AND ADVECT SOMEWHAT WARMER AIR INTO THE REGION AS THE SURFACE HIGH DRIFTS EAST AND AHEAD OF THE NEXT WAVE OF LOW PRESSURE SCHEDULED TO ARRIVE ON SATURDAY. IN THIS REGARD, GUIDANCE TEMPERATURES CALLING FOR HIGHS IN THE TEENS LOOK OK BUT THESE READINGS WILL BE ACCOMPANIED BY A 10 TO 20 MPH WIND AND WIND CHILLS NEAR 10 BELOW ZERO. THERE ARE SOME TIMING DIFFERENCES IN THE 12Z MODELS ON THE HANDLING OF THE SATURDAY WAVE. PREFER THE FASTER SOLUTIONS, OF WHICH THE GFS IS ONE, AS RENEWED HEIGHT FALLS GET UNDERWAY IN CENTRAL CANADA AND ANCHOR THE POLAR VORTEX OVER NORTHERN ONTARIO. THIS SYSTEM WILL BRING OUR BEST CHANCE OF SNOW DURING THE WEEKEND AND REPLENISH THE ARCTIC AIR MASS SATURDAY NIGHT AND SUNDAY. THIS WILL BE THE MOST BRUTAL PORTION OF THE COLD OUTBREAK WHEN FACTORING IN BOTH TEMPERATURE AND WIND TAKING WIND CHILL TO AROUND -20F. THE GFS FORECASTS 850 MB TEMPS TO DROP DOWN NEAR -28C WHICH CORRESPONDS TO DAYTIME TEMPERATURES NO BETTER THAN THE SINGLE DIGITS ON SUNDAY. IN FACT, DAYTIME TEMPERATURES TODAY IN REGIONS OF NORTHERN CANADA SHOW A FEW READINGS STILL BELOW ZERO WITH SIMILAR 850 MB TEMPERATURES. IN ADDITION, THERE WILL LIKELY BE CONSIDERABLY MORE OF A SURFACE PRESSURE TROUGH IN THE LEE OF LAKE MICHIGAN WHICH WILL DIRECT A SW FLOW OF LESS MODIFIED AIR INTO SE MICHIGAN. THE LAST TIME METRO DETROIT HAD AT LEAST TWO CONSECUTIVE DAYS OF SINGLE DIGIT HIGH TEMPERATURES WAS IN JANUARY 1994. VERY LITTLE TEMPERATURE MODERATION IS EXPECTED ON MONDAY AS THE CORE OF THE POLAR VORTEX MOVES OVER THE GREAT LAKES. THE GLOBAL MODELS DO SHOW THE VORTEX MOVING EAST BY TUESDAY BUT DEEP NW FLOW WILL CONTINUE THE SUPPLY OF ARCTIC AIR THROUGH THE MIDDLE OF NEXT WEEK. SOME MODERATION IS POSSIBLE ON TUESDAY AND WEDNESDAY AS THE WIND BACKS TOWARD THE WEST AND NORTHWEST, PREVENTING THE LESS MODIFIED AIR FROM MOVING INTO THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 3 PM THURSDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422... UNTIL 10 AM THURSDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY FOR WINDS...UNTIL 10 AM THURSDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FOR WINDS... && $$ AVIATION...DWD SHORT TERM...JDS LONG TERM....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 416 AM CST THU FEB 1 2007 .DISCUSSION... SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 41 / 80 10 10 10 10 WACO, TX 51 36 45 27 47 / 90 10 10 10 10 PARIS, TX 40 27 35 22 39 / 100 30 10 10 10 DENTON, TX 40 29 36 23 40 / 80 20 10 10 10 MCKINNEY, TX 40 29 35 23 39 / 100 20 10 10 10 DALLAS, TX 41 31 38 24 42 / 90 10 10 10 10 TERRELL, TX 43 31 39 23 43 / 100 10 10 10 10 CORSICANA, TX 48 33 40 24 44 / 90 10 10 10 10 TEMPLE, TX 53 37 50 29 48 / 90 10 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21/05/92 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 1025 AM EST THU FEB 1 2007 ...WARM AND WINDY TODAY WITH GUSTS NEAR GALE FORCE POSSIBLE OVER THE OFFSHORE ATLANTIC WATERS TONIGHT... ...FAST-MOVING SHOWERS AND POTENTIALLY STRONG STORMS MOVING THROUGH TONIGHT... .DISCUSSION... CURRENT...STATE 88D MOSAIC SHOWS THAT THE FEW SPRINKLES AROUND EARLIER THIS MORNING HAVE DISSIPATED. AS EXPECTED BRISK SRLY FLOW HAS DEVELOPED OVER THE CWA THIS MORNING WITH WINDS ALREADY UP TO 15G25MPH AT MOST METAR SITES. VIS IMAGERY SHOWS BKN LOW-MID LEVEL CLOUDS TRAVERSING MAINLY THE NRN CWA. WATERVAPOR IMAGERY/RUC ANLYS FIELDS SHOWS AN IMPRESSIVE SHORT WAVE TROUGH MOVING INTO WEST TX...CAUSING THE TAIL OF STRENGTHENING 160-180KT+ JETSTREAK TO DIP SWD ACROSS THE SERN CONUS. DVLPG SFC LOW PRES CTR CURRENTLY TUCKED UP AGAINST THE TX GULF COAST WITH QSTNY FRONT SNAKING ENE FROM IT OFFSHORE TX/WRN LA...AND THEN INLAND NEAR KMSY AND OVER SRN AL/GA. FCST...WDSPRD L80S (PERHAPS A FEW INTR READINGS NR 85F) ON TAP AS BRISK/GUSTY SSE-S FLOW VEERS TO S-SSW DURING THE AFTN...ALTHOUGH PROBABLY NOT QUITE UP TO NPW/LAKE WIND ADV CRITERIA. LOW PRES CTR STILL PROGGED TO INTENSIFY AND ROCKET ENE-WD ALONG THE FRONTAL BDRY...BRINGING INCRSG RAIN CHCS AND THREAT FOR SVR STORMS (MAINLY STRAIGHT LINE WINDS AS DIRECTIONAL SHEAR DOESN`T LOOK LIKE IT WILL CONTRIBUTE A WHOLE LOT TO TOTAL 0-1KM HELICITY PROFILE. IN ADDITION ...WITH M-U50 TD`S IN PLACE...THE LOCAL AIR MASS HAS A WAYS TO GO TO MODIFY TO WHERE ENOUGH CONDITIONAL INSTABILITY WILL EXIST TO SUPPORT CONVECTION OVERNIGHT. INDEED...06Z BUFKIT DATA INDICATED MARGINAL INSTABILITY (500-800 J/KG) WITH THE TIME OF PEAK CAPE SEVERAL HRS PRIOR TO THE APPROACH OF PRIMARY CONVECTIVE BAND TO THE FAR NRN CWA @09Z-12Z...WHICH IS NEAR THE DIURNAL CONVECTIVE MINIMUM OVER LAND. THAT BEING SAID...ANTICIPATED DEVELOPMENT OF A STRONG LOW LEVEL JET (H85 WINDS OF 50-70KT ACROSS THE NRN PENINSULA) WILL HELP OVERCOME CONVECTIVE INHIBITION OF LOCAL AIR MASS. PWATS ARE PROGGED TO RISE TO NEARLY 2.0". SO WITH STRONG FORCING/IMPRESSIVE DEEP LAYER WIND FIELDS GOING UP AGAINST MARGINAL INSTABILITY...WILL BE INTERESTING TO SEE HOW THIS ALL PLAYS OUT AS CONVECTION IS JUST NOW BEGINNING TO FORM OVER THE GOMEX. WILL UPDATE ZFP TO REMOVE MENTION OF SPRINKLES AND TO ADJUST SKY COVER ACROSS THE SRN HALF CWA TO "PSUNNY". && .AVIATION...VFR WITH BKN TO LCLLY OVC CIGS FL050-080 ACROSS THE MCO/ORL/SFB/DAB AERODROMES. A FEW MVFR CIGS/VSBYS IN DIURNAL SHRA PSBL ~19Z-23Z. INCRSG RAIN CHCS ACROSS MOVING TWD THE NRN AERODROMES AFT 08Z TONIGHT. && .MARINE...CURRENT BUOY/C-MAN OBS SHOW SSE-S WINDS ALEADY AROUND 20KT SUSTAINED ACROSS MUCH OF THE MARINE AREA. EXPECT SOME ADDITIONAL STRENGTHENING THIS AFTN/EVENING...PEAKING @25-30KT OUT OF S-SSW WITH GALE FORCE GUSTS. CURRENT CWF IS ON TOP OF THIS. NO CHGS NECESSARY. && .FIRE WEATHER...STRONG SURFACE/TRANSPORT WINDS THIS AFTN WILL RESULT IN VERY HIGH DISPERSION VALUES. BURN ACTIVITIES WILL BE PROBLEMATIC. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY FOR WINDS THROUGH 10 AM EST FRIDAY FROM FLAGLER BEACH TO JUPITER INLET OUT 20 NM- SMALL CRAFT ADVISORY THROUGH PM EST FRIDAY FROM FLAGLER BEACH TO JUPITER INLET 20 TO 60 NM OFFSHORE- && $$ CRISTALDI fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1103 AM EST THU FEB 1 2007 .SHORT TERM /REST OF TODAY/... 1021 MB SFC HIGH CURRENTLY CENTERED NEAR THE OUTER BANKS OF NC WITH ITS SWRN SECTION WEDGING DOWN THE E SIDE OF THE APPALACHIANS. THE SHARP AIRMASS DELINEATION BETWEEN STRONG WARM ADVECTION TO THE S AND COOL STABLE LAYER TO THE N IS VERY EVIDENT ON MSAS ANALYSES AND MESONET OBS. ON THE SRN EDGE...IT APPEARS TO BE JUST N OF SAVANNAH AND HILTON HEAD...WHILE S OF BEAUFORT. LITTLE MOVEMENT IS ANTICIPATED TODAY AS WIDESPREAD LIGHT TO MODERATE PRECIP IS NOW FALLING INTO THE WEDGE AND MAINTAINING ITS POSITION. UPDATED POPS TO INDICATE HIGHEST VALUES ACROSS SC WITH A SOMEWHAT DELAYED ONSET ACROSS EXTREME SE GA AND THE WATERS. ALSO HAVE REWORKED TEMPS AND DEWPTS ON AN HOURLY BASIS USING LATEST RUC/WRF GUIDANCE. THIS KEEPS FAR INLAND SC IN THE LOWER 40S WHILE EXTREME SE GA COULD REACH THE MID 60S. && .MARINE... SFC OBS SHOW THE FRONTAL BOUNDARY DRAPED RIGHT ACROSS OUR NEARSHORE WATERS THIS MORNING WITH SMALL OSCILLATIONS N OR S. 12 KM WRF AND 40 KM RUC ARE BOTH INITIALIZED PRETTY WELL AND SHOW THE BOUNDARY REMAINING NEARLY STATIONARY TODAY. A SMALL JOG TO THE N IS POSSIBLE LATE IN THE AFTERNOON AS THE 50-60 KT H85 JET DEVELOPS ALONG THE COAST. NEARSHORE WINDS ARE GENERALLY BELOW 20 KT WHILE THE OUTER GA WATERS HAVE SHOWN A STEADY INCREASE TO BETWEEN 25 AND 30 KT AT 10Z. HOWEVER...THE SENSOR ON THE R2 TOWER OVER AMZ374 IS ELEVATED...THUS SAMPLING THE LLJ MUCH BETTER. WAVE HEIGHTS OF 4.3 FT INDICATE MUCH LESS WIND MIXING TO THE SEA SFC. HAVE ADJUSTED WIND DIRECTIONS PER LATEST HIGH-RES MODEL GUIDANCE...KEEPING WINDS NE RIGHT ALONG THE COAST FOR THE FIRST HALF OF THE AFTERNOON WHILE SLY ALL OTHER AREAS. ONLY MADE ONE CHANGE TO FLAGS...TO DELAY ONSET OF THE SCA IN THE HARBOR UNTIL 23Z. THE WEDGE BOUNDARY IS EXPECTED TO REMAIN JUST OFFSHORE THROUGH THIS AFTERNOON AND WINDS SHOULD REMAIN BELOW 20 KT. WILL HEADLINE EXERCISE CAUTION FOR 15-20 KT. ALSO TWEAKED SEAS TO DELAY BUILDING OF HIGHEST SEAS. && .HIGH SURF/COASTAL FLOOD/BEACH EROSION... NO REAL CHANGES TO PREVIOUS THINKING ON THESE TOPICS. WILL NOT GO ANY HIGHER THAN 7 FT ON THE NEARBY COASTAL WATERS TODAY AND EARLY TONIGHT...SO NO NEED FOR ANY HIGH SURF ADVISORY AT THIS TIME. HOWEVER...DEPENDING UPON THE STRENGTH OF THE LOW MOVING IN FROM THE WSW TONIGHT... THERE COULD BE A BRIEF PERIOD WHERE THE SURGING WINDS ALLOW FOR SEAS TO APPROACH 8 FT TONIGHT...ESP ON THE SC WATERS AND WILL CONTINUE TO MONITOR FOR A HIGH SURF ADVISORY. TIDE LEVELS HAVE CHANGED DRAMATICALLY IN THE PAST 24 HOURS...WITH CURRENT TIDES RUNNING ABOVE PREDICTED VALUES. FORTUNATELY THE HIGHER OF THE 2 TIDES TODAY IS EARLY THIS MORNING...AND BY THE TIME WE SEE THE NEXT HIGHER TIDE FRI MORNING THE FLOW IS OFFSHORE. THEREFORE THE RISK OF ANY SHALLOW COASTAL FLOODING APPEARS TO BE LOW. CERTAINLY COULD SEE SOME BEACH EROSION TODAY AND TONIGHT WITH INCREASING ONSHORE WINDS AND BUILDING SEAS AND WILL ADDRESS THIS CONCERN IN THE HWO. && .AVIATION /16Z-12Z/... LOWER CIGS JUST NOW ARRIVING AT TERMS AS LLVL MOISTURE INCREASES. CIGS WILL CONTINUE TO FALL WITH LOWERING INVERSION THIS AFTN AND TONIGHT. WIND FCST DURING THE PERIOD IS TOUGH GIVEN THE UNCERTAIN OSCILLATIONS OF THE FRONTAL BOUNDARY. ONE CERTAINTY IS THE WIND SHEAR. MODERATE TO STRONG S-SW WINDS WILL PREVAIL ABOVE THE INVERSION AND HAVE INCLUDED WIND SHEAR AT BOTH KCHS AND KSAV THRU THE REST OF THE FCST PERIOD. BEST CHANCE FOR HEAVIER PRECIP STILL LOOKS TO BE IN THE LATE AFTN INTO THE EVE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST FRIDAY FOR AMZ330. SMALL CRAFT ADVISORY UNTIL 10 AM EST FRIDAY FOR AMZ352-354. SMALL CRAFT ADVISORY UNTIL 5 PM EST FRIDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR AMZ374. GALE WARNING FROM 10 PM THIS EVENING TO 5 AM EST FRIDAY FOR AMZ374. && $$ JRL ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 1026 AM CST THU FEB 1 2007 .UPDATE... FORECAST UPDATED FOR THIS AFTERNOON TO ACCOUNT FOR RADAR TRENDS AND LATEST 12Z RUC AND NAM RUNS. LIGHT SNOW CONTINUES TO DIMINISH THIS MORNING...WITH NO RADAR OR SURFACE INDICATIONS OF PRECIP WEST OF A PAH TO MVN LINE AT 16Z. OCNL LIGHT SNOW WILL END OVER REMAINDER OF FORECAST AREA IN NEXT FEW HOURS...FOLLOWED BY NOTHING MORE THAN SCTD FLURRIES. NEW 12Z RUC/NAM RUNS AND LATEST RADAR AND SFC REPORTS INDICATE ANY MEASURABLE SNOW WITH THE NEXT SYSTEM WILL NOT ARRIVE BEFORE 00Z...EXCEPT POSSIBLY OVER SE MISSOURI. CHANCE POPS FOR LATE AFTERNOON WILL COVER THESE AREAS. TEMPS ARE RUNNING 2 TO 3 DEGREES HIGHER THAN FORECAST. RAISED HIGHS 2 OR 3 DEGREES MOST AREAS. && .PREV DISCUSSION... GOING FORECAST IN GOOD SHAPE. AT 08Z...INITIAL BATCH OF LIGHT SNOW WAS MOSTLY EAST OF THE MISSISSIPPI RIVER. AMOUNTS HAVE GENERALLY BEEN A DUSTING TO 1/2 INCH...WITH SPOTTY 1 INCH AMOUNTS REPORTED. RADAR AND SATELLITE TRENDS CONFIRM THERE SHOULD BE A LULL THIS MORNING IN THE LIGHT SNOW ACTIVITY. CANNOT RULE OUT SOME TRACE WINTRY PRECIP THIS MORNING. BY MID TO LATE AFTERNOON...THE SECOND ROUND OF LIGHT SNOW SHOULD DEVELOP INTO SOUTHEAST MISSOURI AND EVENTUALLY FAR WEST KENTUCKY. THIS AREA SHOULD TRANSLATE ENE ACROSS THE REGION DURING THE EVENING...WITH HIGHEST POPS ACROSS THE SOUTHERN 1/2 OF THE FA. THE SREF CONGLOMERATE AND NAM ARE A TAD MORE AGGRESSIVE THAN THE GFS LATE TODAY. WILL TREND TOWARD THE SLIGHTLY QUICKER SOLUTIONS SEEN IN THE SREF / NAM OUTPUT. MODELS REMAIN FAIRLY CONSISTENT IN ADVERTISING UPWARDS OF 1 INCH OF SNOW WITH THE SECOND BATCH LATE TODAY AND TONIGHT ACROSS SOUTHERN SECTIONS OF THE FA. THERE MAY BE ISOLATED HIGHER AMOUNTS OF PERHAPS 1 1/2 INCHES OR SO. PRECIP TYPE IS STILL A QUESTION MARK ACROSS THE HOPKINSVILLE AREA...EAST OF THE LAND BETWEEN THE LAKES. THE NAM AND GFS BOUNDARY LAYER TEMPS ARE COOLER FOR 00Z TONIGHT THAN WHAT WAS SHOWN 24 HOURS AGO. 925/850MB UA CHARTS SHOW IT IS STILL VERY COLD OFF THE DECK. SO WE ARE THINKING MAINLY SNOW. HOWEVER WE WILL MAINTAIN A SMALL RAIN CHANCE WITH THE SNOW IN THE AFOREMENTIONED AREA LATE TODAY JUST IN CASE. FURTHER NORTH INTO SOUTHERN ILLINOIS AND SOUTHWEST INDIANA...THE CHANCE OF SNOW EXISTS...BUT THE PROBABILITY IS LOWER. THUS OUR ACCUMULATION FORECAST FOR THIS AREA WILL BE LOWER AS WELL. AT THIS TIME DO NOT PLAN ON AN ADVISORY. WILL CONTINUE TO HANDLE THIS EVENT WITH THE SPECIAL WEATHER STATEMENT PRODUCT. WE DO EXPECT THE SNOW CHANCE TO DIMINISH FROM WEST TO EAST OVERNIGHT. SO WE KEPT WITH OUR GOING CHANCE OF SOME LINGERING VERY LIGHT SNOW OR FREEZING DRIZZLE. NO CHANGES WERE MADE BEYOND TONIGHT. STILL A SLIGHT CHANCE OF SNOW FOR FRIDAY. THE NEXT SYSTEM IS FORECAST TO AFFECT THE AREA SUNDAY INTO SUNDAY NIGHT. THERE IS A CHANCE OF LIGHT SNOW WITH THIS SYSTEM. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGHOUT THE SEVEN DAY PERIOD. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ UPDATE...MY PREVIOUS...CN ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1118 AM EST THU FEB 1 2007 .UPDATE... PARTLY SUNNY SKIES ACRS THE RGN...SKY GRIDS AND ZONES UPDATED ACCORDINGLY. && .PREV DISCUSSION... /ISSUED 903 AM EST THU FEB 1 2007/ UPDATE... SOME MID LVL DRYING ACRS THE BGM FCST AREA TDA, WITH DEEPER MSTR ARRIVING FROM THE SOUTH TWDS EVNG. SAT PIX SHOW SIG BREAKS IN THE MID/UPR DECK TO OUR W AND SW, AND WILL BE MORE OPTIMISTIC WITH SKY COVER (LEANING TWDS RUC SKY GRIDS WITH PC TO MC SKIES). SOME --SHSN ACRS ERN ZONES, BUT THESE ARE DSPTNG AND XPCT TREND TO CONTINUE, SO A DRY FCST FOR THIS AFTN. PREV DISCUSSION... /ISSUED 618 AM EST THU FEB 1 2007/ AVIATION /12Z-12Z/... BROKEN MID DECK THIS MORNING WILL PERSIST THROUGH THE DAY. WINDS WILL BE LIGHT OUT OF THE SOUTH THIS MORNING, AND WILL INCREASE TO 8-12 KTS OUT OF THE SOUTHWEST THIS AFTERNOON. A STRAY LIGHT SNOW SHOWER IS POSSIBLE BUT VFR CONDITIONS ARE FORECAST. LIGHT SNOW WILL OVERSPREAD EARLY FRIDAY MORNING. EXPECT CIGS TO LOWER TO MVFR AROUND 06Z WITH VIS FALLING TO 2-4SM IN LIGHT SNOW MAINLY FROM ITH-BGM SOUTHWARD TO ELM-AVP. DJP PREV DISCUSSION... /ISSUED 305 AM EST THU FEB 1 2007/ SHORT TERM /TODAY THROUGH FRIDAY NIGHT/... HIGH PRESSURE IS SLIDING OFF THE EAST COAST THIS MORNING. RISING MOTION TO THE WEST IS IMPORTING A MID DECK OF CLOUD COVER, AND MAY PRODUCE A FEW STRAY SNOW SHOWERS TODAY. MEANWHILE A WAVE MOVING THROUGH THE GULF STATES WILL CAUSE A STRONGER CYCLONE TO FORM TONIGHT. THIS STORM WILL QUICKLY MOVE UP THE ATLANTIC SEABOARD. MODEL TRENDS REMAIN SIMILAR TO WHAT WE SAW PVS 24H...THAT SYSTEM WILL REMAIN FAR ENOUGH OUT TO SEA TO KEEP SIG SNOW WELL EAST OF OUR FA. HOWEVER SYSTEM WILL BE RESPONSIBLE FOR LIGHT SNOW OVER MUCH OF THE REGION, WITH POSSIBILITY OF AN INCH OR TWO ACCUMULATION OVER SOUTHEASTERN ZONES. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER ENTIRE REGION, FIRST SPREADING INTO NE PA LATE TONIGHT AND THEN OVER REMAINDER OF REGION BETWEEN 11Z-15Z. COLD AIR WILL POUR DOWN FROM CANADA BEHIND THE CYCLONE AS TROF DEEPENS INTO THE OHIO VALLEY. WITH THE AXIS UPSTREAM, WE WILL BE IN A COLD SOUTHWESTERLY FLOW, WHICH SHOULD KEEP LAKE EFFECT MAINLY NORTH OF THE REGION. HAVE ADJUSTED GRIDS TO REFLECT PERIPHERY OF POSSIBLE SNOW BANDS OVER NORTHERN FINGER LAKES, AND NORTHWESTERN PORTION OF MOHAWK VALLEY. DJP LONG TERM /SATURDAY THROUGH WEDNESDAY/... HAVE PRETTY MUCH FOLLOWED HPC GUIDANCE THRU EXTENDED. STILL LOOKING AT BLO NORMAL TEMPS TO CONTINUE DURG THE PERIOD. HIGHS EXPECTED TO BE IN THE TEENS AND LOWS IN THE SINGLE DIGITS AND/OR BLO ZERO. WK ISENTROPIC LIFT EXPECTED ON SATURDAY WITH SCTD SNOW SHOWERS. CLIPPER COMES THRU ON SAT NIGHT INTO SUN WITH LAKE EFFECT KICKING IN BEHIND IT. BOTH 06Z/12Z GFS KICKS OUT SFC LOW INTO CNTRL PLAIN ON MONDAY AND TRACKS IT ALONG MASON-DIXON LINE MON AND MON NIGHT. EURO KEEPS LOW FURTHER SOUTH WITH CANADIAN FASTER AND FURTHER NORTH. STILL A LOT OF UNCERTAINTY WITH THIS SYSTEM...ALTHOUGH 12Z GFS SLIGHTLY FURTHER SOUTH WITH QPF AMTS THAN THE 06Z RUN. THIS WOULD KEEP MOST OF SNOW SOUTH OF FA. HAVE OPTED TO GO WITH MORE LES DURING THIS PERIOD THAN SYNOPTIC SCALE SNOWS BUT THIS WILL NEED TO BE WATCHED. PB AVIATION /08Z-06Z/... VERY QUIET TODAY WITH JUST A FEW FLURRIES OR LIGHT SNOW SHOWERS EXPECTED. THESE WILL BE WIDELY SCATTERED, SO DID NOT INCLUDE IN TERMINAL FORECASTS. MID DECK WILL LOWER TO A VFR STRATOCU DECK LATER TODAY. DJP && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 903 AM EST THU FEB 1 2007 .UPDATE... SOME MID LVL DRYING ACRS THE BGM FCST AREA TDA, WITH DEEPER MSTR ARRIVING FROM THE SOUTH TWDS EVNG. SAT PIX SHOW SIG BREAKS IN THE MID/UPR DECK TO OUR W AND SW, AND WILL BE MORE OPTIMISTIC WITH SKY COVER (LEANING TWDS RUC SKY GRIDS WITH PC TO MC SKIES). SOME --SHSN ACRS ERN ZONES, BUT THESE ARE DSPTNG AND XPCT TREND TO CONTINUE, SO A DRY FCST FOR THIS AFTN. && .PREV DISCUSSION... /ISSUED 618 AM EST THU FEB 1 2007/ AVIATION /12Z-12Z/... BROKEN MID DECK THIS MORNING WILL PERSIST THROUGH THE DAY. WINDS WILL BE LIGHT OUT OF THE SOUTH THIS MORNING, AND WILL INCREASE TO 8-12 KTS OUT OF THE SOUTHWEST THIS AFTERNOON. A STRAY LIGHT SNOW SHOWER IS POSSIBLE BUT VFR CONDITIONS ARE FORECAST. LIGHT SNOW WILL OVERSPREAD EARLY FRIDAY MORNING. EXPECT CIGS TO LOWER TO MVFR AROUND 06Z WITH VIS FALLING TO 2-4SM IN LIGHT SNOW MAINLY FROM ITH-BGM SOUTHWARD TO ELM-AVP. DJP PREV DISCUSSION... /ISSUED 305 AM EST THU FEB 1 2007/ SHORT TERM /TODAY THROUGH FRIDAY NIGHT/... HIGH PRESSURE IS SLIDING OFF THE EAST COAST THIS MORNING. RISING MOTION TO THE WEST IS IMPORTING A MID DECK OF CLOUD COVER, AND MAY PRODUCE A FEW STRAY SNOW SHOWERS TODAY. MEANWHILE A WAVE MOVING THROUGH THE GULF STATES WILL CAUSE A STRONGER CYCLONE TO FORM TONIGHT. THIS STORM WILL QUICKLY MOVE UP THE ATLANTIC SEABOARD. MODEL TRENDS REMAIN SIMILAR TO WHAT WE SAW PVS 24H...THAT SYSTEM WILL REMAIN FAR ENOUGH OUT TO SEA TO KEEP SIG SNOW WELL EAST OF OUR FA. HOWEVER SYSTEM WILL BE RESPONSIBLE FOR LIGHT SNOW OVER MUCH OF THE REGION, WITH POSSIBILITY OF AN INCH OR TWO ACCUMULATION OVER SOUTHEASTERN ZONES. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER ENTIRE REGION, FIRST SPREADING INTO NE PA LATE TONIGHT AND THEN OVER REMAINDER OF REGION BETWEEN 11Z-15Z. COLD AIR WILL POUR DOWN FROM CANADA BEHIND THE CYCLONE AS TROF DEEPENS INTO THE OHIO VALLEY. WITH THE AXIS UPSTREAM, WE WILL BE IN A COLD SOUTHWESTERLY FLOW, WHICH SHOULD KEEP LAKE EFFECT MAINLY NORTH OF THE REGION. HAVE ADJUSTED GRIDS TO REFLECT PERIPHERY OF POSSIBLE SNOW BANDS OVER NORTHERN FINGER LAKES, AND NORTHWESTERN PORTION OF MOHAWK VALLEY. DJP LONG TERM /SATURDAY THROUGH WEDNESDAY/... HAVE PRETTY MUCH FOLLOWED HPC GUIDANCE THRU EXTENDED. STILL LOOKING AT BLO NORMAL TEMPS TO CONTINUE DURG THE PERIOD. HIGHS EXPECTED TO BE IN THE TEENS AND LOWS IN THE SINGLE DIGITS AND/OR BLO ZERO. WK ISENTROPIC LIFT EXPECTED ON SATURDAY WITH SCTD SNOW SHOWERS. CLIPPER COMES THRU ON SAT NIGHT INTO SUN WITH LAKE EFFECT KICKING IN BEHIND IT. BOTH 06Z/12Z GFS KICKS OUT SFC LOW INTO CNTRL PLAIN ON MONDAY AND TRACKS IT ALONG MASON-DIXON LINE MON AND MON NIGHT. EURO KEEPS LOW FURTHER SOUTH WITH CANADIAN FASTER AND FURTHER NORTH. STILL A LOT OF UNCERTAINTY WITH THIS SYSTEM...ALTHOUGH 12Z GFS SLIGHTLY FURTHER SOUTH WITH QPF AMTS THAN THE 06Z RUN. THIS WOULD KEEP MOST OF SNOW SOUTH OF FA. HAVE OPTED TO GO WITH MORE LES DURING THIS PERIOD THAN SYNOPTIC SCALE SNOWS BUT THIS WILL NEED TO BE WATCHED. PB AVIATION /08Z-06Z/... VERY QUIET TODAY WITH JUST A FEW FLURRIES OR LIGHT SNOW SHOWERS EXPECTED. THESE WILL BE WIDELY SCATTERED, SO DID NOT INCLUDE IN TERMINAL FORECASTS. MID DECK WILL LOWER TO A VFR STRATOCU DECK LATER TODAY. DJP && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 1020 AM EST THU FEB 1 2007 .SHORT TERM /TODAY/...PRIMARILY SNOW FALLING ALONG AND WEST OF THE HIGHWAY 17 CORRIDOR AND HAVE ISSUED SNOW ADVISORIES FOR THESE AREAS UNTIL NOON. STILL ANTICIPATE ENOUGH WARMING IN THE LOW LEVELS TO CHANGE ALL PRECIPITATION TO RAIN BY MIDDAY. HAVE ALREADY SEEN SOME ACCUMULATIONS OVER GREENE...PITT...LENOIR AND DUPLIN COUNTIES WITH UP TO AN INCH AND A HALF IN LENOIR COUNTY. REST OF THE CWA WILL HAVE ALL RAIN WITH SOME DECENT QPF AMOUNTS NEAR THE COAST. HAVE ADJUSTED MAX TEMPS DOWN A COUPLE OF DEGREES AS WELL FOR THE AFTERNOON. && .AVIATION /15Z-12Z/...GENERALLY IFR WITH RAIN WITH SOME SNOW AT THE WESTERN TAF SITES (PGV, ISO) UNTIL AROUND 16 OR 17Z. && .MARINE...WILL MAKE SOME MINOR TWEAKS TO WIND DIRECTION BASED ON CURRENT OBS AND BLEND IT INTO THE RUC SOLUTIONS FOR THE AFTERNOON. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...SNOW ADVISORY UNTIL NOON EST TODAY FOR NCZ029-044-045-079-080- 090-091. MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST FRIDAY FOR AMZ130-135-150. SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SATURDAY FOR AMZ154-156-158. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST SATURDAY FOR AMZ152. && $$ COLLINS nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 839 AM EST THU FEB 1 2007 .UPDATE... CANCELED THE FREEZING RAIN ADVISORY. ALL ASOS AND MESONET SITES SEEM TO BE ABOVE FREEZING. NRN ZONES STILL SHOWING SOME SUB- FREEZING DEWPOINTS BUT WET BULB TEMPS SHOULD REMAIN ABOVE 32. KLTX SHOWING A WELL DEFINED BRIGHTBAND ACRS NRN BLADEN AND ROBESON AND TO A LESSER EXTENT MARLBORO. REPORTS FROM THESE LOCALES INDICATE THAT SOME IP AND WET SNOWFLAKES ARE MIXING WITH THE RAIN. ZFP AND GRIDS WILL IDICATE AS SUCH. RUC SOUNDINGS INIDCATE THAT BY 15Z OR 16Z THAT WETBULB TEMP WILL BE FREEZING OR ABOVE THROUGH ABOUT 800MB AT WHICH TIME ANY AND ALL MIXING SHOULD BE OVER WITH. && .PREV DISCUSSION... /ISSUED 645 AM EST THU FEB 1 2007/ SHORT TERM /THROUGH TODAY/... REGIONAL RADAR LOOPS AND SURFACE OBSERVATIONS SHOW PRECIPITATION HAS BEEN SLOW TO DEVELOP ACROSS THE AREA. IT APPEARS THE GFS DEPICTION...WHICH HAS BEEN THE MODEL OF CHOICE...IS A LITTLE TOO QUICK TO DEVELOP PRECIP. NONETHELESS...LIGHT RAIN WILL STILL DEVELOP LATER THIS MORNING ACROSS WESTERN AREAS WHERE TEMPERATURES ARE CRITICAL. INTENSE SOUNDING SCRUTINY SHOW A WINDOW OF OPPORTUNITY FOR SOME LIGHT FREEZING RAIN ACROSS WEST AND NORTHWESTERN AREAS AS WET BULB TEMPS ARE AT OR SLIGHTLY BELOW FREEZING. INTERESTING ENOUGH...IN THE FAR NORTHWEST CORNER OF THE AREA TOP DOWN ANALYSIS ACTUALLY SHOWS THE POSSIBILITY FOR A BRIEF PERIOD OF SNOW...WITH WARM NOSE TEMPS. AROUND 2 DEGREES CELSIUS. WILL REFRAIN FROM THE MENTION OF SNOW HOWEVER. ALL OF THIS SAID...HAVE EXPANDED THE FREEZING RAIN ADVISORY TO INCLUDE ROBESON...BLADEN COUNTIES IN NORTH CAROLINA WHILE ADDING DILLON...FLORENCE...AND MARION COUNTIES IN SOUTH CAROLINA. ALL PRECIP. SHOULD BE RAIN BY 1500 UTC. FOR THE REMAINDER OF THE DAY...DEEP LAYER OMEGA...MAXIMIZED AROUND 1800 UTC...WARRANTS CATEGORICAL POPS ALL AREAS. BASICALLY USED A BLEND OF GUIDANCE NUMBERS AS THERE ARE NO DISCERNIBLE TRENDS IN THE PRODUCTS. SHOULD SEE UPPER 40S ALONG THE COAST WITH AROUND 40 WESTERN AREAS. MID TERM /TONIGHT THROUGH SATURDAY/... NO CONCERNS ABOUT WINTRY PRECIPITATION THIS PERIOD AS TEMPS WILL STAY ABOVE FREEZING THROUGH TONIGHT. TWO MAIN AREAS OF LOW PRESSURE WILL MOVE NE ALONG A COASTAL TROUGH TONIGHT EACH ACCOMPANIED BY A SLUG OF DEEP MOISTURE EMBEDDED IN A DEEP SW FLOW. JUXTAPOSITION OF THE TROUGH WILL ULTIMATELY DETERMINE THE TRACK OF LOW PRESSURE AND THE AMOUNT OF RAINFALL THE AREA RECEIVES. AT THIS TIME...STORM TOTAL QPF LOOKS TO BE HIGHEST ALONG THE COAST WHERE AROUND 2 INCHES COULD FALL WITH AMOUNTS CLOSER TO AN INCH WELL INLAND. HOWEVER...THAT BEING SAID...AMOUNTS OVER 3 INCHES WILL LIKELY BE LURKING JUST OFFSHORE. ONE INCH TO AROUND TWO INCHES OF RAIN WILL BE ENOUGH FOR SIGNIFICANT PONDING OF WATER IN LOW LYING AREA...BUT A FLOOD WATCH IS NOT WARRANTED. THIS AMOUNT OF RAIN WILL LIKELY BE ENOUGH TO SEND SOME RIVERS TO OR OVER FLOOD STAGE DURING THE WEEKEND. RAIN SHOULD COME TO AN END FROM SW TO NE LATE TONIGHT...PERHAPS LINGERING TO AROUND DAYBREAK FAR NE. LOW LEVEL INVERSION IS EXPECTED TO BREAK MID TO LATE MORNING ON FRI AND THIS SHOULD ALLOW DRIER AIR AND STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE. SW TO W WINDS WILL ALLOW TEMPS TO REBOUND NICELY SO MOST AREAS SHOULD CRACK 50 DEG...PERHAPS TOUCHING NEAR 60 IN A FEW SPOTS. HIGH PRESSURE OF PACIFIC ORIGIN WILL BUILD SOLIDLY ACROSS THE CAROLINAS FRI NIGHT AND SAT. TEMPS WILL BE NEAR NORMAL TO SLIGHTLY ABOVE AND NO PRECIPITATION IS EXPECTED. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...HIGH PRESSURE WILL GET SHUNTED S AND E LATE IN THE WEEKEND. MONDAY NIGHT...AN ARCTIC FRONT WILL BLAST ACROSS THE EASTERN CAROLINAS BRINGING IN THE COLDEST AIRMASS OF THE SEASON. 1000-500 MB THICKNESSES ON THE 12Z GFS DROP AS LOW AS 519DM ACROSS THE NORTH CAROLINA COUNTIES...EQUATING TO HIGHS ONLY IN THE 30S-LOW 40S WITH LOWS DEEP INTO THE TEENS. TUESDAY NIGHT WILL LIKELY BE THE COLDEST NIGHT EVEN IF THE GFS IS CORRECT IN KEEPING WINDS UP AND THE ATMOSPHERE FROM DECOUPLING. IF THE HIGH IS A LITTLE FARTHER EAST AND WINDS DO DECOUPLE...WATCH FOR THE POSSIBILITY OF SINGLE-DIGIT LOWS FOR SOME INLAND AREAS...AND POTENTIALLY THE COLDEST TEMPERATURES SINCE FEB 5 1996. AVIATION...UPDATED LOOKS LIKE ONLY CHANCE OF FROZEN OR FREEZING PRECIP WILL BE FOR LBT ONLY THROUGH 14Z WITH ALL RAIN AFTERWARDS. CEILINGS WILL LOWER TO IFR OVER WESTERN TERMINALS BY MID MORNING WITH IFR CEILINGS ALONG THE COAST BY EARLY AFTERNOON. PRECIP WILL GET FAIRLY HEAVY LATER TODAY AS COASTAL LOW DEVELOPS ALONG WITH STRONG OMEGA. CEILINGS/VIS WILL STABLIZE...BOTH IFR...FOR ALMOST THE REMAINDER OF THE FORECAST PERIOD. WINDS WILL LIKLY BE VARIABLE ALONG THE COAST THIS AFTERNOON AND EVENING AS THE LOW TRACKS NORTHEASTWARD...WITH ALL NORTHEAST WINDS OVER FLO AND LBT. MARINE... SHORT TERM /THROUGH TODAY/... STRONG SOUTH TO SOUTHWESTERLY FLOW WILL DEVELOP ACROSS THE COASTAL WATERS LATER TODAY AS COASTAL TROUGH DEVELOPS AND HOVERS ALONG THE COAST. ALTHOUGH THE TIMING WILL BE DELAYED SOMEWHAT...WILL MAINTAIN SMALL CRAFT ADVISORY ALL WATERS BEGINNING AT 9 AM THIS MORNING FOR THE SAKE OF CONTINUITY. MID TERM /TONIGHT THROUGH SATURDAY/... COASTAL TROUGH WILL BE SITUATED ACROSS THE WATERS TONIGHT...WITH TWO AREAS OF LOW PRESSURE EXPECTED TO MOVE ALONG THIS TROUGH. WINDS WILL GET A LITTLE ERRATIC AS THESE AREAS OF LOW PRESSURE MOVE ACROSS THE AREA. GENERALLY STRONG SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TONIGHT WITH THE PREDOMINATE WIND DIRECTION FROM THE N...SHIFTING TO THE NW OVERNIGHT. SEAS WILL BE PEAKING TONIGHT IN 6 TO 9 FT RANGE. NEAR SHORE...OFFSHORE WINDS WILL KEEP SEAS CLOSER TO 5 FT. WINDS WILL BE SLOW TO DIMINISH ON FRI AS GRADIENT WILL BE SLOW TO RELAX DUE TO PRESSURE DIFFERENCES BETWEEN DEPARTING AND INTENSIFYING AREA OF LOW PRESSURE TO NE AND HIGH PRESSURE BUILDING IN FROM THE W. WINDS AND SEAS WILL CONTINUE TO LOWER FRI NIGHT AND SAT AS HIGH PRESSURE BUILDS ACROSS THE WATERS. LONG TERM /SATURDAY NIGHT THROUGH MONDAY/... A STALLED FRONT WILL REMAIN WELL OFFSHORE THROUGH THE PERIOD WITH COLD NORTHERLY FLOW CONTINUING THROUGH THE WEEKEND. RAW...BLUSTERY WEATHER IS EXPECTED TO DEVELOP SATURDAY NIGHT INTO SUNDAY AS MOISTURE OVERRUNNING THE FRONT PRODUCES AREAS OF RAIN ACROSS THE COASTAL WATERS. SURFACE HIGH PRESSURE WILL MOVE SLOWLY EAST FROM THE MID-MISSISSIPPI VALLEY SATURDAY INTO THE CENTRAL APPALACHIANS BY SUNDAY EVENING. THE 12Z GFS LOOKS VERY SIMILAR TO THE PREVIOUS FORECAST AND IS THE BASIS FOR THIS WIND FORECAST. WAVEWATCH SEAS ALSO LOOK GOOD. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 4 PM EST FRIDAY FOR AMZ254-256. SMALL CRAFT ADVISORY FROM NOON TODAY TO 7 PM EST FRIDAY FOR AMZ250-252. && $$ UPDATE...MBB SHORT TERM...SHK MID TERM...RJD LONG TERM...TRA AVIATION...DL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 433 AM CST THU FEB 1 2007 .SHORT TERM (TODAY-SUN)...LIGHT SNOW IS ONGOING ACROSS THE AREA AND ALREADY APPROACHING A HALF INCH ACCUMULATED FOR SOME PLACES. ARCTIC FRONT WILL SOON REACH YBR AND YWG AND ENTER THE U.S. AT LEAST BY 15Z. CLEARING LINE FOLLOWS THE FRONT BUT ANY CLEARING WILL LAST ONLY A FEW HOURS WITH MORE HIGH CLOUDS ALREADY MOVING SOUTH IN CENTRAL MANITOBA. AND CLEARING MIGHT NOT AS NOTICEABLE ANYWAY BECAUSE OF BLOWING SNOW. ONLY 25 TO 30 KNOTS OF WIND IS AVAILABLE TO MIX TOWARDS SURFACE TODAY FROM 925-850 MB. SUFFICIENTLY ADIABATIC LAPSE RATE SHOULD ALLOW THIS TO OCCUR AS COLD ADVECTION AT THOSE LEVELS CONTINUE THROUGH THE DAY. BUT THE SURFACE PRESSURE GRADIENT ALONE IS ENOUGH TO PRODUCE ABOUT 20 KNOTS SUSTAINED WHICH MAY PICK THE ACCUMULATING FLUFF AND SUBSTANTIALLY REDUCE VISIBILITIES MOST OF TODAY. RUC SHOWS BOUNDARY LAYER WINDS IN EXCESS OF 20 KNOTS FROM THE NORTHERN RED RIVER VALLEY WESTWARD BY 18Z AND BELIEVE THIS IS SUFFICIENT TO SUPPORT SNOW AND BLOWING SNOW ADVISORY CONDITIONS... AND DID SO FOR JUST WEST OF THE VALLEY. BUT WILL HAVE TO WATCH FOR A POSSIBLE EXTENSION OF THE ADVISORY THROUGH THE VALLEY NORTH OF FARGO. BITTER COLD FOLLOWS FOR TONIGHT AND A LONG TERM WIND CHILL ADVISORY WILL ALMOST CERTAINLY BE NECESSARY...POSSIBLY LASTING UNTIL WE REACH WIND CHILL WARNING CRITERIA ACROSS MOST OF THE REGION FOR FRIDAY NIGHT/SAT MORNING. MOSTLY CLOUDY CONDITIONS FRIDAY THROUGH SATURDAY WILL NOT HELP KEEP THE SURFACE MUCH WARMER AS THEY USUALLY DO THIS TIME OF YEAR. IN-CLOUD TEMPERATURES IN EXCESS OF -30C WILL NOT RADIATE ENOUGH TO WARM THE SURFACE. .LONG TERM...NO CHANGE TO EXTENDED FORECAST BEYOND SUNDAY. MEX GUIDANCE AND GFS SHOW GOOD PERSISTENCE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS AFTERNOON FOR NDZ006-007-014-015-024-026-054. WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 PM CST THIS EVENING FOR NDZ028-038-049-052-053. MN...NONE. && $$ GV/ nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 936 AM CST THU FEB 1 2007 .DISCUSSION... HAVE UPDATED ZONES TO INCLUDE THUNDER IN THE WESTERN HALF OF THE FORECAST AREA AS BOTH THE NAM AND GFS INDICATED 700-500MB LAPSE RATES INCREASING TO 7.0-7.5 C/KM IN THIS AREA. THERE ARE A COUPLE DECENT STORMS JUST TO THE SW OF THE CWA ALREADY. ALSO...WILL CONTINUE MENTION OF AREAS OF FOG AREAWIDE AT LEAST THROUGH 18Z WITH MANY STATIONS STILL REPORTING VISBYS IN THE 1-2 MI RANGE. ALSO ADJUSTED DEWPOINTS. /13 && .PREV DISCUSSION... /ISSUED 539 AM CST THU FEB 1 2007/ UPDATE... PRECIP SHIELD IS EXPANDING A BIT MORE THAN EARLIER ANTICIPATED. HAVE INCREASED POPS THIS MORNING AND LINGERED PRECIP LONGER THIS AFTERNOON AND EVENING DUE TO SECOND IMPULSE TRIGGERING MORE PRECIP OVER WEST TX. UPDATED PRODUCTS AVAILABLE SHORTLY. SCHULTZ AVIATION... FOR THE 12Z TAFS...-RA SHOULD BE PREVAILING THROUGH THE MID AFTERNOON HOURS. VSBYS MAY TEMPORARILY DROP INTO IFR/LIFR CAT THIS MORNING...WITH LIFR/VLIFR CIGS. VSBYS AND CIGS SHOULD RECOVER INTO MVFR CAT BY THE AFTERNOON AND INTO THE EVENING HOURS AS PRECIP TAPERS OFF. 05/21 DISCUSSION..../ISSUED 416 AM CST THU FEB 1 2007/ SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 / 100 20 10 10 WACO, TX 50 36 45 27 / 100 10 10 10 PARIS, TX 40 27 35 22 / 100 30 10 10 DENTON, TX 40 29 36 23 / 100 20 10 10 MCKINNEY, TX 40 29 35 23 / 100 20 10 10 DALLAS, TX 41 31 38 24 / 100 20 10 10 TERRELL, TX 43 31 39 23 / 100 20 10 10 CORSICANA, TX 46 33 40 24 / 100 20 10 10 TEMPLE, TX 53 37 50 29 / 100 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99 tx AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE FORT WORTH TX 539 AM CST THU FEB 1 2007 .UPDATE... PRECIP SHIELD IS EXPANDING A BIT MORE THAN EARLIER ANTICIPATED. HAVE INCREASED POPS THIS MORNING AND LINGERED PRECIP LONGER THIS AFTERNOON AND EVENING DUE TO SECOND IMPULSE TRIGGERING MORE PRECIP OVER WEST TX. UPDATED PRODUCTS AVAILABLE SHORTLY. SCHULTZ && .AVIATION... FOR THE 12Z TAFS...-RA SHOULD BE PREVAILING THROUGH THE MID AFTERNOON HOURS. VSBYS MAY TEMPORARILY DROP INTO IFR/LIFR CAT THIS MORNING...WITH LIFR/VLIFR CIGS. VSBYS AND CIGS SHOULD RECOVER INTO MVFR CAT BY THE AFTERNOON AND INTO THE EVENING HOURS AS PRECIP TAPERS OFF. 05/21 && .DISCUSSION..../ISSUED 416 AM CST THU FEB 1 2007/ SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 41 / 80 10 10 10 10 WACO, TX 51 36 45 27 47 / 90 10 10 10 10 PARIS, TX 40 27 35 22 39 / 100 30 10 10 10 DENTON, TX 40 29 36 23 40 / 80 20 10 10 10 MCKINNEY, TX 40 29 35 23 39 / 100 20 10 10 10 DALLAS, TX 41 31 38 24 42 / 90 10 10 10 10 TERRELL, TX 43 31 39 23 43 / 100 10 10 10 10 CORSICANA, TX 48 33 40 24 44 / 90 10 10 10 10 TEMPLE, TX 53 37 50 29 48 / 90 10 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21/05/92 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 254 PM MST WED JAN 31 2007 .SHORT TERM... (TONIGHT AND THURSDAY) MAIN FORECAST CONCERN REMAIN SNOW AMOUNTS TONIGHT. CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS INDICATING BROAD UPPER TROUGH ACROSS THE UPPER GREAT LAKES BACK THROUGH THE ROCKIES WITH TROUGH AXIS MOVING ACROSS NORTHWEST COLORADO ATTM. WATER VAPOR IMAGERY ALSO INDICATING YET ANOTHER SYSTEM DIVING NORTH OUT OF CENTRAL CANADA AND INTO THE NORTHERN TIER STATES ATTM. AT THE SFC...COLD FRONT WHICH BLASTED ACROSS EASTERN COLORADO EARLY THIS MORNING IS CURRENTLY BACKED UP ACROSS THE EASTERN MTS THROUGH EASTERN NEW MEXICO AND ACROSS WESTERN TEXAS PANHANDLE ATTM AS HIGH PRESSURE CONTINUES TO BUILD INTO THE SOUTHERN HIGH PLAINS. REGIONAL SATELLITE AND RADARS INDICATING CLOUD TOP COOLING AND WIDESPREAD ECHOES ACROSS WESTERN AND SOUTH CENTRAL COLORADO ATTM. FOR TONIGHT...UPPER TROUGH CONTINUES TO TRANSLATE ACROSS THE STATE WITH TROUGH AXIS MOVING ACROSS SOUTH CENTRAL COLORADO AROUND 06Z THU AND INTO SOUTHWEST KANSAS BY 12Z...AS NEXT CANADIAN SYSTEM CONTINUES TO MOVE INTO THE NORTHERN ROCKIES. MOISTURE AND LIFT ASSOCIATED WITH PASSING SYSTEM SHOULD CONTINUE TO MOVE ACROSS SOUTH CENTRAL COLORADO THIS EVENING AND INTO WESTERN KANSAS OVERNIGHT WITH ASSOCIATED PRECIPITATION DIMINISHING QUICKLY FROM WEST TO EAST WITH PASSAGE OF TROUGH AXIS...SAVE THE CENTRAL MTS WITH CONTINUED OROGRAPHIC FLOWS. HAVE KEPT CURRENT HIGHLIGHTS IN PLACE ACROSS THE SW AND CENTRAL MTS WITH ANOTHER 1 TO 4 INCHES EXPECTED THROUGH THE EVENING. SPOTTER REPORTS INDICATING GENERALLY UNDER 2 INCHES HAS FALLEN ACROSS THE EASTERN MTS ATTM...THOUGH WITH EAST TO NORTHEAST LOW LEVEL UPSLOPE CONTINUING TO DEVELOP...WILL KEPT CURRENT HIGHLIGHTS ACROSS THE SOUTHEASTERN MTS AS WELL...WITH ADDITIONAL ACCUMS BETWEEN 2 AND 6 INCHES EXPECTED...WITH HIGHEST AMOUNTS ACROSS THE SOUTHERN SANGRE DE CRISTO MTS. SNOW HAS BEEN RATHER SPOTTY ACROSS THE I-25 CORRIDOR THUS FAR...BUT EXPECT THAT TO INCREASE AS TROUGH MOVES ACROSS THE AREA WITH AN ADDITIONAL 1 TO 3 INCHES POSSIBLE...ESPECIALLY WESTERN AREAS CLOSER TO THE HIGHER TERRAIN. NOT EXPECTING MUCH IN THE WAY OF ACCUMULATING PRECIP ACROSS THE FAR EASTERN PLAINS...BUT CANT RULE OUT A FEW SNOW SHOWERS OVERNIGHT AHEAD OF PASSING SYSTEM. WITH COLD AIR IN PLACE...OVERNIGHT LOWS TO REMAIN BELOW SEASONAL AVERAGES...AND HAVE GONE AOB COOLEST GUIDANCE...ESPECIALLY THE SAN LUIS AND LOWER ARKANSAS VALLEYS WITH PARTIAL CLEARING EXPECTED BY MORNING. ON THURSDAY...NORTHWEST FLOW ALOFT INCREASES ACROSS THE STATE AS NEXT SYSTEM CONTINUES TO DIVE INTO THE NORTHERN ROCKIES WITH ASSOCIATED FRONTAL BOUNDARY PROGGED TO MOVE ACROSS NORTHEAST COLORADO BY LATE AFTERNOON. HAVE FOLLOWED CLOSER TO GFS SOLUTION WITH FASTER MOVEMENT OF FRONTAL BOUNDARY...AND HAVE INTRODUCED CHANCE POPS ACROSS THE EASTERN MTS AND ALONG THE PALMER DVD FOR THE AFTERNOON. WITH MOISTURE AND LIFT AND OROGRAPHIC FLOW INCREASING ACROSS THE CENTRAL MTS...HAVE GONE WITH LIKELY POPS WITH 1 TO 3 INCHES POSSIBLE THROUGH THE AFTERNOON. -MW .LONG TERM... (THU NIGHT THROUGH WED) ...FLUFFY SNOW ANTICIPATED FOR THU NIGHT INTO FRI... ...PREPARE NOW FOR EXTREMELY COLD TEMPERATURES FRI-WEEKEND... ...DANGEROUS WIND CHILL VALUES POSSIBLE FRI NIGHT-SAT... THU NIGHT AND FRI...NEXT CANADIAN WEATHER SYSTEM WILL BE TAKING AIM ON THE CENTRAL ROCKIES AND THIS IS STRONGEST ONE OF THE ARCTIC SYSTEM INTRUSIONS. SIGNIFICANT COLD FRONT SHOULD BE BLASTING THROUGH CO THU NIGHT AND COULD BE FASTER. A LITTLE BETTER AND DEEPER SYNOPTIC SCALE ASCENT IMPLIED GIVEN THE DYNAMICS. H5-H3 DIV-Q IMPLIED UPWARD VERTICAL MOTION JUXTAPOSED WITH H8-H7 AND H7-H6 IMPLIED UPWARD VERTICAL MOTION PER 2-D PETTERSON ANALYSES. BOTH 12KM WRF AND GFS HAVE THIS SCENARIO FOR THU NIGHT INTO FRI MORNING...SO CONFIDENCE IS SOMEWHAT HIGH OF PRECIPITATION AND ACCUMULATING SNOWFALL. HAVE INCREASED POPS TO HIGH "LIKELYS" FOR THU NIGHT INTO FRI MORNING FOR THE CENTRAL AND EASTERN MOUNTAINS INCLUDING THE I-25 CORRIDOR. GIVEN THE THERMAL STRUCTURE ALONG THE FRONT...EXCELLENT DENDRITIC SNOW GROWTH WILL BE LIKELY IN THE MOIST LAYER RESULTING IN 20-1 TO 40-1 SNOW RATIOS PRODUCING FLUFFY SNOW THAT CAN ADD UP QUICKLY IN LOW WATER CONTENT SNOWFALL. MIGHT NEED SOME ADVISORIES FOR OUR EASTERN CO MOUNTAINS AND I-25 CORRIDOR AS THE EVENT NEARS. PRECIPITATION CHANCES SHOULD BE DIMINISHING BY FRI AFTERNOON. TEMPERATURES WILL LIKELY BE STEADY OR SLOWLY FALLING FRI...BUT IF THE PRECIPITATION STOPS DURING THE THE AFTERNOON...THEN THERE COULD BE A COUPLE OF DEGREES RECOVERY. CURRENT TEMPERATURES FORECAST LOOKS ON TARGET AND ONLY MINOR SPATIAL CONSISTENCY ISSUES WERE TAKEN CARE OF. FRI NIGHT AND SAT...12KM WRF AND GFS KIND OF DIVERGE IN TERMS OF THE AMOUNT OF MIDLEVEL TEMPERATURES WARMING THAT OCCURS. THE GFS IS SLIGHTLY WARMER IN THE MIDLEVEL FRI NIGHT THROUGH SAT...WHILE THE WRF HAS H7 TEMPERATURES -18C TO -26C EVEN DURING THE DAYTIME PERIOD SAT. IT SHOULD BE MUCH BELOW AVERAGE CHILLY TEMPERATURES...EITHER EXTREMELY COLD OR VERY COLD. SUB-ZERO LOW TEMPERATURES WILL BE HIGHLY PROBABLE ACROSS MUCH SOUTHERN CO LOCATIONS FRI NIGHT AND STRUGGLING TO WARM SAT...ESPECIALLY IN TRAPPED VALLEYS AND OVER DENSE SNOW-PACK. A BIG FORECAST CONCERN WILL BE DANGEROUS WIND CHILLS FRI NIGHT INTO SAT. COULD REACH WARNING VALUES IN THE MOUNTAINS(E.G. -35F OR LOWER) AND ADVISORY TO MAYBE WARNING VALUES AT THE LOWER ELEVATIONS. MOST AREAS WILL SEE WIND CHILL VALUES OF -15F TO -35F LATE FRI NIGHT AND SAT MORNING. WIND CHILL HEADLINES MAY BE NEEDED AS THE EVENT GETS CLOSER AND THE HAZARDOUS WEATHER OUTLOOK HAS THIS HANDLED WELL RIGHT NOW. ANY PRECIPITATION POTENTIAL WOULD LIKELY BY AROUND THE CONTINENTAL DIVIDE GIVEN THE WEST-NORTHWEST FLOW ALOFT. SUN THROUGH WED...NORTHWEST FLOW DEVELOPS SUN AND INTO EARLY NEXT WEEK AS THE EXTREMELY COLD TROUGH MIGRATES EASTWARD. MIDLEVEL WARMING STARTS SUN AND THE BIGGEST CHALLENGE WILL BE WHEN AND IF THE LOW LEVEL ARCTIC AIR MASS RECEDES FROM EASTERN CO AND GETS "MIXED OUT" FROM THE HIGH MOUNTAIN VALLEYS. HAVE TRENDED TOWARDS A MODERATING TEMPERATURE TREND...BUT HELD TEMPERATURES BACK A LITTLE IN HIGH VALLEYS AND DENSE SNOW-PACK AREAS LIKE KLAA. HPC GUIDANCE HAS A SIGNIFICANT WARM-UP FORECAST FOR TUE AND WED. THIS MAY BE VALID AS A PATTERN CHANGE TO WESTERLY FLOW GIVEN MANY OF THE ENSEMBLE MEMBERS. THE CHALLENGE WILL CONTINUE TO BE THE WARM-UP OVER DENSE SNOW-PACK...WHERE HPC AND MOS GUIDANCE HAVE BEEN TOO WARM PER GRIDDED VERIFICATION DATA. METZE && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY UNTIL 11 PM MST THIS EVENING FOR COZ058>060-066- 068-072>075-079-080. && $$ 23/17 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 1025 AM EST THU FEB 1 2007 ...WARM AND WINDY TODAY WITH GUSTS NEAR GALE FORCE POSSIBLE OVER THE OFFSHORE ATLANTIC WATERS TONIGHT... ...FAST-MOVING SHOWERS AND POTENTIALLY STRONG STORMS MOVING THROUGH TONIGHT... .DISCUSSION... CURRENT...STATE 88D MOSAIC SHOWS THAT THE FEW SPRINKLES AROUND EARLIER THIS MORNING HAVE DISSIPATED. AS EXPECTED BRISK SRLY FLOW HAS DEVELOPED OVER THE CWA THIS MORNING WITH WINDS ALREADY UP TO 15G25MPH AT MOST METAR SITES. VIS IMAGERY SHOWS BKN LOW-MID LEVEL CLOUDS TRAVERSING MAINLY THE NRN CWA. WATERVAPOR IMAGERY/RUC ANLYS FIELDS SHOWS AN IMPRESSIVE SHORT WAVE TROUGH MOVING INTO WEST TX...CAUSING THE TAIL OF STRENGTHENING 160-180KT+ JETSTREAK TO DIP SWD ACROSS THE SERN CONUS. DVLPG SFC LOW PRES CTR CURRENTLY TUCKED UP AGAINST THE TX GULF COAST WITH QSTNY FRONT SNAKING ENE FROM IT OFFSHORE TX/WRN LA...AND THEN INLAND NEAR KMSY AND OVER SRN AL/GA. FCST...WDSPRD L80S (PERHAPS A FEW INTR READINGS NR 85F) ON TAP AS BRISK/GUSTY SSE-S FLOW VEERS TO S-SSW DURING THE AFTN...ALTHOUGH PROBABLY NOT QUITE UP TO NPW/LAKE WIND ADV CRITERIA. LOW PRES CTR STILL PROGGED TO INTENSIFY AND ROCKET ENE-WD ALONG THE FRONTAL BDRY...BRINGING INCRSG RAIN CHCS AND THREAT FOR SVR STORMS (MAINLY STRAIGHT LINE WINDS AS DIRECTIONAL SHEAR DOESN`T LOOK LIKE IT WILL CONTRIBUTE A WHOLE LOT TO TOTAL 0-1KM HELICITY PROFILE. IN ADDITION ...WITH M-U50 TD`S IN PLACE...THE LOCAL AIR MASS HAS A WAYS TO GO TO MODIFY TO WHERE ENOUGH CONDITIONAL INSTABILITY WILL EXIST TO SUPPORT CONVECTION OVERNIGHT. INDEED...06Z BUFKIT DATA INDICATED MARGINAL INSTABILITY (500-800 J/KG) WITH THE TIME OF PEAK CAPE SEVERAL HRS PRIOR TO THE APPROACH OF PRIMARY CONVECTIVE BAND TO THE FAR NRN CWA @09Z-12Z...WHICH IS NEAR THE DIURNAL CONVECTIVE MINIMUM OVER LAND. THAT BEING SAID...ANTICIPATED DEVELOPMENT OF A STRONG LOW LEVEL JET (H85 WINDS OF 50-70KT ACROSS THE NRN PENINSULA) WILL HELP OVERCOME CONVECTIVE INHIBITION OF LOCAL AIR MASS. PWATS ARE PROGGED TO RISE TO NEARLY 2.0". SO WITH STRONG FORCING/IMPRESSIVE DEEP LAYER WIND FIELDS GOING UP AGAINST MARGINAL INSTABILITY...WILL BE INTERESTING TO SEE HOW THIS ALL PLAYS OUT AS CONVECTION IS JUST NOW BEGINNING TO FORM OVER THE GOMEX. WILL UPDATE ZFP TO REMOVE MENTION OF SPRINKLES AND TO ADJUST SKY COVER ACROSS THE SRN HALF CWA TO "PSUNNY". && .AVIATION...VFR WITH BKN TO LCLLY OVC CIGS FL050-080 ACROSS THE MCO/ORL/SFB/DAB AERODROMES. A FEW MVFR CIGS/VSBYS IN DIURNAL SHRA PSBL ~19Z-23Z. INCRSG RAIN CHCS ACROSS MOVING TWD THE NRN AERODROMES AFT 08Z TONIGHT. && .MARINE...CURRENT BUOY/C-MAN OBS SHOW SSE-S WINDS ALEADY AROUND 20KT SUSTAINED ACROSS MUCH OF THE MARINE AREA. EXPECT SOME ADDITIONAL STRENGTHENING THIS AFTN/EVENING...PEAKING @25-30KT OUT OF S-SSW WITH GALE FORCE GUSTS. CURRENT CWF IS ON TOP OF THIS. NO CHGS NECESSARY. && .FIRE WEATHER...STRONG SURFACE/TRANSPORT WINDS THIS AFTN WILL RESULT IN VERY HIGH DISPERSION VALUES. BURN ACTIVITIES WILL BE PROBLEMATIC. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY FOR WINDS THROUGH 10 AM EST FRIDAY FROM FLAGLER BEACH TO JUPITER INLET OUT 20 NM- SMALL CRAFT ADVISORY THROUGH PM EST FRIDAY FROM FLAGLER BEACH TO JUPITER INLET 20 TO 60 NM OFFSHORE- && $$ CRISTALDI fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 430 AM EST THU FEB 01 2007 .SYNOPSIS... 07Z WATER VAPOR AND RUC ANALYSIS SHOWING A MUCH MORE ZONAL PATTERN ALONG THE EAST COAST AND DOWN TO THE GULF COAST. THIS WILL BE VERY SHORT LIVED AS ENERGY NOW DIVING THROUGH THE MID SECTION OF THE COUNTY WILL CONTINUE TO DIG SOUTH AND EAST AND AMPLIFY THE PATTERN THROUGH THE NEXT 24 TO 36 HOURS. AT THE SURFACE WE SEE HIGH PRESSURE BEGINNING TO SLIP OFF THE CAROLINA COAST AS LOW PRESSURE ORGANIZES IN THE WESTERN GULF OF MEXICO. A WARM FRONT EXTENDING EAST FROM THIS LOW IS NOW MOVING UP INTO THE CENTRAL AND NORTHEASTERN GULF OF MEXICO. THIS LOW WILL BE OUR WEATHER MAKER INTO EARLY FRIDAY MORNING. AS THE LOW HAS ORGANIZED OVERNIGHT PLENTY OF CLOUDS HAVE SPILLED EASTWARD OVER THE SOUTHEAST. AREAS OF PRECIPITATION HAVE ALSO BEEN ON THE MOVE TOWARD THE EAST AND NORTHEAST WITH THE MAIN THRUST OF THE PRECIP UP ACROSS MS/AL/AND NORTHERN GEORGIA SO FAR. ACROSS THESE AREAS THE COLD AIR IS MORE DEEPLY ENTRENCHED AND AREAS OF SLEET AND FREEZING RAIN HAVE BEEN OCCURRING. && .SHORT TERM... (TODAY-SATURDAY) LOW PRESSURE WILL CONTINUE TO DEVELOP ACROSS THE NORTH-CENTRAL GULF OF MEXICO TODAY WITH AREAS OF RAIN AND ISOLATED THUNDERSTORMS SPREADING EAST THROUGH THE DAY. THE EASTERN PORTION OF THE CWA IS LIKELY TO BE INITIALLY FAIRLY DRY WITH THE EXCEPTION OF A FEW WIDELY SCATTERED SHOWERS AND HAVE LOWERED POPS FOR THE FIRST HALF OF THE DAY. AREAS OF RAIN WILL THEN OVERSPREAD THE ENTIRE AREA THROUGH THE AFTERNOON AS THE LOW AND BETTER DYNAMICS APPROACH. SO FAR THE BEST ISENTROPIC LIFT HAS REMAINED TO OUR NORTH WHERE AREAS OF RAIN/FREEZING RAIN/SLEET AND SNOW HAVE BEEN WIDESPREAD THIS OVERNIGHT. WITH THE FORECAST LOW TRACK...THE WARMFRONT IS NOT LIKELY TO PENETRATE INLAND VERY RAPIDLY. HIGH TEMPERATURES IN THE MIDDLE TO UPPER 50S ACROSS OUR NORTHERN ZONES WILL LIKELY NOT BE REALIZED UNTIL LATE IN THE DAY WITH COOL CONDITIONS BEING EXPERIENCE IN THESE AREAS NORTH OF THE WARM FRONT. SPC CONTINUES TO COVER PORTIONS OF NORTH FLORIDA INTO FAR SOUTHERN GEORGIA WITH A SLIGHT RISK OF SEVERE WEATHER THIS AFTERNOON INTO THE EVENING. AT THIS TIME THINK ANY SEVERE WEATHER LOOKS TO BE ISOLATED IN NATURE...BUT SHEAR PROFILES DO INDICATE THAT ANY SURFACE BASED STORMS THAT GET GOING IN THE WARM SECTOR WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS AND ISOLATED TORNADOES. WILL CONTINUE TO WATCH THE SITUATION AND HAVE HIGHLIGHTED THE SEVERE THREAT IN THE GRIDS AND HWO. COLD FRONT WILL CROSS THE REGION OVERNIGHT BRINGING A END TO THE SEVERE THREAT FROM WEST TO EAST. FRONT AND QPF FIELDS SHOULD CLEAR OUR AREA BY LATE MORNING ALTHOUGH CLOUDS MAY BE A BIT MORE STUBBORN... ESPECIALLY ACROSS THE FLORIDA BIG BEND. FURTHER WEST AND NORTH WILL EXPECT AT LEAST SOME SUN BY THE AFTERNOON. HIGH TEMPERATURES WILL BE NEAR OR SLIGHTLY BELOW NORMAL FRIDAY AFTERNOON WITH MAINLY UPPER 50S TO MIDDLE 60S AS THERE IS NOT A SIGNIFICANT COOL PUSH BEHIND THIS SYSTEM. HIGH PRESSURE CONTINUE TO BUILD EAST ALONG THE GULF COAST FRIDAY NIGHT INTO SATURDAY. THIS IS WHERE THE FORECAST BECOME A BIT TRICKY. GUIDANCE IS SHOWING THE FRONT TO OUR SOUTH MAKING SOME HEADWAY BACK NORTH WITH A BAND OF ISENTROPIC LIFT ON THE 295-300K SURFACES TRYING TO GET BACK UP INTO OUR AREA. THE NAM IS MUCH MORE AGGRESSIVE WITH THIS FEATURE AND SPREADS WIDESPREAD QPF BACK OVER THE ENTIRE FORECAST AREA SATURDAY AND SATURDAY NIGHT. THE GFS IS SHOWING THE HIGH TO OUR WEST NOSING IN SIGNIFICANTLY MORE AND HOLDING MUCH OF THIS LIFT AND MOISTURE INTO NORTH FLORIDA AND THE NORTHEASTERN GULF. THE GFS HAS STRONG SUPPORT FROM BOTH THE ECMWF AND UKMET ON THIS SCENARIO. DISCUSSIONS WITH SURROUNDING OFFICES AND HPC SHOW AN AGREEMENT THAT THIS MORE SUPPRESSED SOLUTION IS THE BETTER WAY TO GO AND HAVE DRAWN MY POP GRIDS TO REPRESENT. ONLY HAVE SLIGHT TO LOW END CHANCE POPS FOR SHOWERS OVER THE NORTH WITH MID TO HIGH CHANCE POPS OVER NORTH FLORIDA SAT/SAT NIGHT. AS WAS MENTIONED LAST NIGHT THIS IS A RATHER COOL AIRMASS TRYING TO COME IN SATURDAY NIGHT AND A FEW FLAKES OF SNOW OR A FEW ICE PELLETS CAN NOT BE RULED OUT OVER PORTIONS OF THE AREAS SAT NIGHT...BUT STILL BELIEVE THE QPF WILL EXIT AHEAD OF THE REAL COOL AIR PUSH. EITHER WAY ANY FROZEN PRECIP WOULD BE LIGHT AND NOT AMOUNT TO MUCH OF ANYTHING...WILL CONTINUE TO WATCH. .LONG TERM... (SUNDAY-THURSDAY) ANY LINGERING SHOWERS WILL EXIT SOUTH OF THE AREA EARLY SUNDAY MORNING. AS IT LOOKS NOW AN EXTENDED PERIOD OF DRY AND COOL WEATHER WILL THEN BE WITH US INTO THE MIDDLE PART OF NEXT WEEK. BOTH GFS/ECMWF SHOWING HIGH PRESSURE OVER THE REGION BY SUNDAY EVENING INTO MONDAY. THIS HIGH THEN BRIEFLY WEAKENS MONDAY NIGHT BEFORE A STRONGER AND MORE DOMINANT HIGH BUILDS JUST NORTH OF THE AREA FOR TUESDAY INTO THURSDAY. THIS HIGH IS LIKELY TO BRING WITH IT PLENTY OF COOL AND DRY AIR ON NORTHERLY TO NORTHEASTERLY FLOW. AT THIS TIME THE POSITION OF THE HIGH WOULD BE TO FAR NORTH TO ALLOW ANY NIGHTS OF SIGNIFICANT RADIATIONAL COOLING...BUT THIS IS QUITE A WAY INTO THE FUTURE FOR DETAILS. && .AVIATION... LOCAL RADARS AND AIRPORT OBSERVATIONS SHOW THAT SO FAR THE LOWER ATMOSPHERE IS TOO DRY TO ALLOW THE LIGHT RAIN TO FALL TO THE SURFACE. WE EXPECT THESE CONDITIONS TO PERSIST THROUGH THE OVERNIGHT AND EARLY MORNING HOURS. IT APPEARS THAT THE BEST CHANCE FOR RAIN WILL BE THIS AFTERNOON...EARLY AFTERNOON FOR KDHN AND KPFN...AND MID TO LATE AFTERNOON FOR KTLH...KABY...AND KVLD. OCCASIONAL THUNDER IS EXPECTED...MAINLY AT KPFN...KTLH...AND KVLD...WHERE THE INSTABILITY IS GREATER. VFR CEILINGS ARE FORECAST FOR THE OVERNIGHT HOURS...BUT THE CEILINGS WILL GRADUALLY LOWER TO MVFR (AROUND 2500 FT) THIS MORNING AND REMAIN MVFR THROUGHOUT THE DAY. THE VISIBILITY WILL ALSO BE REDUCED TO MVFR IN AREAS OF MODERATE RAIN...BUT LOCAL IFR CONDITIONS ARE POSSIBLE IN THE HEAVIER SHOWERS. WE THINK THE HEAVIEST RAIN WILL GRADUALLY DIMINISH FROM WEST TO EAST THIS EVENING...FOLLOWED BY A LONGER PERIOD OF MOSTLY LIGHT RAIN UNTIL ABOUT 06 UTC. && .MARINE... LOW PRESSURE DEVELOPING IN THE CENTRAL GULF OF MEXICO WILL MOVE NORTHEAST TODAY PASSING NORTH OF THE COASTAL WATERS TONIGHT. WIND AND SEAS HAVE INCREASED TO SMALL CRAFT ADVISORY LEVELS AND WILL CONTINUE ELEVATED THROUGH TONIGHT. WINDS INITIALLY OUT OF THE SOUTHEAST WILL COME AROUND TO SOUTHWEST BY THIS EVENING. NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THIS EVENING WITH A FEW OF THE STORMS REACHING SEVERE LIMITS. COLD FRONT WILL CROSS THE WATERS TONIGHT WITH WINDS COMING AROUND TO THE NORTHWEST AND DECREASING BELOW ADVISORY LEVELS. HIGH PRESSURE THEN BUILDS ACROSS THE WATERS THROUGH FRIDAY NIGHT. THE GRADIENT WILL INCREASE AGAIN FROM SATURDAY THROUGH MONDAY WITH NEAR CAUTION LEVEL WINDS AND SEAS...ESPECIALLY ACROSS THE OFFSHORE LEGS. && .FIRE WEATHER... A LOW PRESSURE SYSTEM AND ASSOCIATED FRONT WILL MOVE EAST ACROSS THE SOUTHEAST U.S. TODAY AND TONIGHT...BRINGING WITH IT WIDESPREAD RAIN TO THE REGION. THE RAIN WILL GRADUALLY END FROM NORTHWEST TO SOUTHEAST LATE TONIGHT AND EARLY FRIDAY AS A COLD FRONT MOVES SOUTH INTO THE GULF. THIS FRONT WILL STALL ACROSS THE GULF THIS WEEKEND...BRINGING A BRIEF RETURN OF RAIN CHANCES UNTIL SUNDAY AFTERNOON...WHEN ANOTHER PUSH OF DRY AIR FORCES THE CLOUDS AND SHOWERS FAR DOWN INTO THE GULF. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 65 54 64 45 53 / 90 90 20 20 50 PANAMA CITY 65 54 62 45 55 / 90 90 10 20 50 DOTHAN 59 48 60 39 53 / 90 80 10 10 30 ALBANY 57 49 62 40 52 / 90 90 10 10 30 VALDOSTA 64 54 65 45 54 / 80 90 20 20 40 CROSS CITY 69 62 69 49 60 / 60 90 40 30 50 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...SMALL CRAFT ADVISORY IN EFFECT ALL ZONES THROUGH 7 AM EST /6 AM CST/ FRIDAY MORNING. && $$ AVIATION...FOURNIER REST OF DISCUSSION...MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1159 AM EST THU FEB 1 2007 .MARINE UPDATE...LATEST OBS FROM FBIS C-MAN SITE INDICATE THE PRESSURE GRADIENT HAS RAPIDLY TIGHTENED RIGHT ALONG THE CHS COUNTY COAST. SUSTAINED WINDS AROUND 20 KT WITH SOME HIGHER GUSTS HAVE NOW APPEARED AT FBIS AS WELL AS BEACH LOCATIONS IN CHARLESTON COUNTY. DOWNTOWN CHS SENSOR JUST RECENTLY REPORTED SUSTAINED WINDS OF 20-25 KT...WITH THE CHS PILOT BOAT REPORTING SIMILAR READINGS. WAVES OF 1 FT NEAR THE PILOT BOAT DOCK WERE SEEN...WITH 2-3 FT NEAR THE HARBOR ENTRANCE. PLAN TO HOIST A SMALL CRAFT ADVY FOR THE CHS HARBOR FOR TODAY AND TONIGHT. UPDATED CWF OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 1103 AM EST THU FEB 1 2007/ SHORT TERM /REST OF TODAY/... 1021 MB SFC HIGH CURRENTLY CENTERED NEAR THE OUTER BANKS OF NC WITH ITS SWRN SECTION WEDGING DOWN THE E SIDE OF THE APPALACHIANS. THE SHARP AIRMASS DELINEATION BETWEEN STRONG WARM ADVECTION TO THE S AND COOL STABLE LAYER TO THE N IS VERY EVIDENT ON MSAS ANALYSES AND MESONET OBS. ON THE SRN EDGE...IT APPEARS TO BE JUST N OF SAVANNAH AND HILTON HEAD...WHILE S OF BEAUFORT. LITTLE MOVEMENT IS ANTICIPATED TODAY AS WIDESPREAD LIGHT TO MODERATE PRECIP IS NOW FALLING INTO THE WEDGE AND MAINTAINING ITS POSITION. UPDATED POPS TO INDICATE HIGHEST VALUES ACROSS SC WITH A SOMEWHAT DELAYED ONSET ACROSS EXTREME SE GA AND THE WATERS. ALSO HAVE REWORKED TEMPS AND DEWPTS ON AN HOURLY BASIS USING LATEST RUC/WRF GUIDANCE. THIS KEEPS FAR INLAND SC IN THE LOWER 40S WHILE EXTREME SE GA COULD REACH THE MID 60S. MARINE... SFC OBS SHOW THE FRONTAL BOUNDARY DRAPED RIGHT ACROSS OUR NEARSHORE WATERS THIS MORNING WITH SMALL OSCILLATIONS N OR S. 12 KM WRF AND 40 KM RUC ARE BOTH INITIALIZED PRETTY WELL AND SHOW THE BOUNDARY REMAINING NEARLY STATIONARY TODAY. A SMALL JOG TO THE N IS POSSIBLE LATE IN THE AFTERNOON AS THE 50-60 KT H85 JET DEVELOPS ALONG THE COAST. NEARSHORE WINDS ARE GENERALLY BELOW 20 KT WHILE THE OUTER GA WATERS HAVE SHOWN A STEADY INCREASE TO BETWEEN 25 AND 30 KT AT 10Z. HOWEVER...THE SENSOR ON THE R2 TOWER OVER AMZ374 IS ELEVATED...THUS SAMPLING THE LLJ MUCH BETTER. WAVE HEIGHTS OF 4.3 FT INDICATE MUCH LESS WIND MIXING TO THE SEA SFC. HAVE ADJUSTED WIND DIRECTIONS PER LATEST HIGH-RES MODEL GUIDANCE...KEEPING WINDS NE RIGHT ALONG THE COAST FOR THE FIRST HALF OF THE AFTERNOON WHILE SLY ALL OTHER AREAS. ALSO TWEAKED SEAS TO DELAY BUILDING OF HIGHEST SEAS. HIGH SURF/COASTAL FLOOD/BEACH EROSION... NO REAL CHANGES TO PREVIOUS THINKING ON THESE TOPICS. WILL NOT GO ANY HIGHER THAN 7 FT ON THE NEARBY COASTAL WATERS TODAY AND EARLY TONIGHT...SO NO NEED FOR ANY HIGH SURF ADVISORY AT THIS TIME. HOWEVER...DEPENDING UPON THE STRENGTH OF THE LOW MOVING IN FROM THE WSW TONIGHT... THERE COULD BE A BRIEF PERIOD WHERE THE SURGING WINDS ALLOW FOR SEAS TO APPROACH 8 FT TONIGHT...ESP ON THE SC WATERS AND WILL CONTINUE TO MONITOR FOR A HIGH SURF ADVISORY. TIDE LEVELS HAVE CHANGED DRAMATICALLY IN THE PAST 24 HOURS...WITH CURRENT TIDES RUNNING ABOVE PREDICTED VALUES. FORTUNATELY THE HIGHER OF THE 2 TIDES TODAY IS EARLY THIS MORNING...AND BY THE TIME WE SEE THE NEXT HIGHER TIDE FRI MORNING THE FLOW IS OFFSHORE. THEREFORE THE RISK OF ANY SHALLOW COASTAL FLOODING APPEARS TO BE LOW. CERTAINLY COULD SEE SOME BEACH EROSION TODAY AND TONIGHT WITH INCREASING ONSHORE WINDS AND BUILDING SEAS AND WILL ADDRESS THIS CONCERN IN THE HWO. AVIATION /16Z-12Z/... LOWER CIGS JUST NOW ARRIVING AT TERMS AS LLVL MOISTURE INCREASES. CIGS WILL CONTINUE TO FALL WITH LOWERING INVERSION THIS AFTN AND TONIGHT. WIND FCST DURING THE PERIOD IS TOUGH GIVEN THE UNCERTAIN OSCILLATIONS OF THE FRONTAL BOUNDARY. ONE CERTAINTY IS THE WIND SHEAR. MODERATE TO STRONG S-SW WINDS WILL PREVAIL ABOVE THE INVERSION AND HAVE INCLUDED WIND SHEAR AT BOTH KCHS AND KSAV THRU THE REST OF THE FCST PERIOD. BEST CHANCE FOR HEAVIER PRECIP STILL LOOKS TO BE IN THE LATE AFTN INTO THE EVE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY AMZ330-352-354-350. GALE WARNING AMZ374. && $$ JRL ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1159 AM EST THU FEB 1 2007 .MARINE UPDATE...LATEST OBS FROM FBIS C-MAN SITE INDICATE THE PRESSURE GRADIENT HAS RAPIDLY TIGHTENED RIGHT ALONG THE CHS COUNTY COAST. SUSTAINED WINDS AROUND 20 KT WITH SOME HIGHER GUSTS HAVE NOW APPEARED AT FBIS AS WELL AS BEACH LOCATIONS IN CHARLESTON COUNTY. DOWNTOWN CHS SENSOR JUST RECENTLY REPORTED SUSTAINED WINDS OF 20-25 KT...WITH THE CHS PILOT BOAT REPORTING SIMILAR READINGS. WAVES OF 1 FT NEAR THE PILOT BOAT DOCK WERE SEEN...WITH 2-3 FT NEAR THE HARBOR ENTRANCE. PLAN TO HOIST A SMALL CRAFT ADVY FOR THE CHS HARBOR FOR TODAY AND TONIGHT. UPDATED CWF OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 1103 AM EST THU FEB 1 2007/ SHORT TERM /REST OF TODAY/... 1021 MB SFC HIGH CURRENTLY CENTERED NEAR THE OUTER BANKS OF NC WITH ITS SWRN SECTION WEDGING DOWN THE E SIDE OF THE APPALACHIANS. THE SHARP AIRMASS DELINEATION BETWEEN STRONG WARM ADVECTION TO THE S AND COOL STABLE LAYER TO THE N IS VERY EVIDENT ON MSAS ANALYSES AND MESONET OBS. ON THE SRN EDGE...IT APPEARS TO BE JUST N OF SAVANNAH AND HILTON HEAD...WHILE S OF BEAUFORT. LITTLE MOVEMENT IS ANTICIPATED TODAY AS WIDESPREAD LIGHT TO MODERATE PRECIP IS NOW FALLING INTO THE WEDGE AND MAINTAINING ITS POSITION. UPDATED POPS TO INDICATE HIGHEST VALUES ACROSS SC WITH A SOMEWHAT DELAYED ONSET ACROSS EXTREME SE GA AND THE WATERS. ALSO HAVE REWORKED TEMPS AND DEWPTS ON AN HOURLY BASIS USING LATEST RUC/WRF GUIDANCE. THIS KEEPS FAR INLAND SC IN THE LOWER 40S WHILE EXTREME SE GA COULD REACH THE MID 60S. MARINE... SFC OBS SHOW THE FRONTAL BOUNDARY DRAPED RIGHT ACROSS OUR NEARSHORE WATERS THIS MORNING WITH SMALL OSCILLATIONS N OR S. 12 KM WRF AND 40 KM RUC ARE BOTH INITIALIZED PRETTY WELL AND SHOW THE BOUNDARY REMAINING NEARLY STATIONARY TODAY. A SMALL JOG TO THE N IS POSSIBLE LATE IN THE AFTERNOON AS THE 50-60 KT H85 JET DEVELOPS ALONG THE COAST. NEARSHORE WINDS ARE GENERALLY BELOW 20 KT WHILE THE OUTER GA WATERS HAVE SHOWN A STEADY INCREASE TO BETWEEN 25 AND 30 KT AT 10Z. HOWEVER...THE SENSOR ON THE R2 TOWER OVER AMZ374 IS ELEVATED...THUS SAMPLING THE LLJ MUCH BETTER. WAVE HEIGHTS OF 4.3 FT INDICATE MUCH LESS WIND MIXING TO THE SEA SFC. HAVE ADJUSTED WIND DIRECTIONS PER LATEST HIGH-RES MODEL GUIDANCE...KEEPING WINDS NE RIGHT ALONG THE COAST FOR THE FIRST HALF OF THE AFTERNOON WHILE SLY ALL OTHER AREAS. ALSO TWEAKED SEAS TO DELAY BUILDING OF HIGHEST SEAS. HIGH SURF/COASTAL FLOOD/BEACH EROSION... NO REAL CHANGES TO PREVIOUS THINKING ON THESE TOPICS. WILL NOT GO ANY HIGHER THAN 7 FT ON THE NEARBY COASTAL WATERS TODAY AND EARLY TONIGHT...SO NO NEED FOR ANY HIGH SURF ADVISORY AT THIS TIME. HOWEVER...DEPENDING UPON THE STRENGTH OF THE LOW MOVING IN FROM THE WSW TONIGHT... THERE COULD BE A BRIEF PERIOD WHERE THE SURGING WINDS ALLOW FOR SEAS TO APPROACH 8 FT TONIGHT...ESP ON THE SC WATERS AND WILL CONTINUE TO MONITOR FOR A HIGH SURF ADVISORY. TIDE LEVELS HAVE CHANGED DRAMATICALLY IN THE PAST 24 HOURS...WITH CURRENT TIDES RUNNING ABOVE PREDICTED VALUES. FORTUNATELY THE HIGHER OF THE 2 TIDES TODAY IS EARLY THIS MORNING...AND BY THE TIME WE SEE THE NEXT HIGHER TIDE FRI MORNING THE FLOW IS OFFSHORE. THEREFORE THE RISK OF ANY SHALLOW COASTAL FLOODING APPEARS TO BE LOW. CERTAINLY COULD SEE SOME BEACH EROSION TODAY AND TONIGHT WITH INCREASING ONSHORE WINDS AND BUILDING SEAS AND WILL ADDRESS THIS CONCERN IN THE HWO. AVIATION /16Z-12Z/... LOWER CIGS JUST NOW ARRIVING AT TERMS AS LLVL MOISTURE INCREASES. CIGS WILL CONTINUE TO FALL WITH LOWERING INVERSION THIS AFTN AND TONIGHT. WIND FCST DURING THE PERIOD IS TOUGH GIVEN THE UNCERTAIN OSCILLATIONS OF THE FRONTAL BOUNDARY. ONE CERTAINTY IS THE WIND SHEAR. MODERATE TO STRONG S-SW WINDS WILL PREVAIL ABOVE THE INVERSION AND HAVE INCLUDED WIND SHEAR AT BOTH KCHS AND KSAV THRU THE REST OF THE FCST PERIOD. BEST CHANCE FOR HEAVIER PRECIP STILL LOOKS TO BE IN THE LATE AFTN INTO THE EVE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY AMZ330-352-354-350. GALE WARNING AMZ374. && $$ JRL ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1103 AM EST THU FEB 1 2007 .SHORT TERM /REST OF TODAY/... 1021 MB SFC HIGH CURRENTLY CENTERED NEAR THE OUTER BANKS OF NC WITH ITS SWRN SECTION WEDGING DOWN THE E SIDE OF THE APPALACHIANS. THE SHARP AIRMASS DELINEATION BETWEEN STRONG WARM ADVECTION TO THE S AND COOL STABLE LAYER TO THE N IS VERY EVIDENT ON MSAS ANALYSES AND MESONET OBS. ON THE SRN EDGE...IT APPEARS TO BE JUST N OF SAVANNAH AND HILTON HEAD...WHILE S OF BEAUFORT. LITTLE MOVEMENT IS ANTICIPATED TODAY AS WIDESPREAD LIGHT TO MODERATE PRECIP IS NOW FALLING INTO THE WEDGE AND MAINTAINING ITS POSITION. UPDATED POPS TO INDICATE HIGHEST VALUES ACROSS SC WITH A SOMEWHAT DELAYED ONSET ACROSS EXTREME SE GA AND THE WATERS. ALSO HAVE REWORKED TEMPS AND DEWPTS ON AN HOURLY BASIS USING LATEST RUC/WRF GUIDANCE. THIS KEEPS FAR INLAND SC IN THE LOWER 40S WHILE EXTREME SE GA COULD REACH THE MID 60S. && .MARINE... SFC OBS SHOW THE FRONTAL BOUNDARY DRAPED RIGHT ACROSS OUR NEARSHORE WATERS THIS MORNING WITH SMALL OSCILLATIONS N OR S. 12 KM WRF AND 40 KM RUC ARE BOTH INITIALIZED PRETTY WELL AND SHOW THE BOUNDARY REMAINING NEARLY STATIONARY TODAY. A SMALL JOG TO THE N IS POSSIBLE LATE IN THE AFTERNOON AS THE 50-60 KT H85 JET DEVELOPS ALONG THE COAST. NEARSHORE WINDS ARE GENERALLY BELOW 20 KT WHILE THE OUTER GA WATERS HAVE SHOWN A STEADY INCREASE TO BETWEEN 25 AND 30 KT AT 10Z. HOWEVER...THE SENSOR ON THE R2 TOWER OVER AMZ374 IS ELEVATED...THUS SAMPLING THE LLJ MUCH BETTER. WAVE HEIGHTS OF 4.3 FT INDICATE MUCH LESS WIND MIXING TO THE SEA SFC. HAVE ADJUSTED WIND DIRECTIONS PER LATEST HIGH-RES MODEL GUIDANCE...KEEPING WINDS NE RIGHT ALONG THE COAST FOR THE FIRST HALF OF THE AFTERNOON WHILE SLY ALL OTHER AREAS. ONLY MADE ONE CHANGE TO FLAGS...TO DELAY ONSET OF THE SCA IN THE HARBOR UNTIL 23Z. THE WEDGE BOUNDARY IS EXPECTED TO REMAIN JUST OFFSHORE THROUGH THIS AFTERNOON AND WINDS SHOULD REMAIN BELOW 20 KT. WILL HEADLINE EXERCISE CAUTION FOR 15-20 KT. ALSO TWEAKED SEAS TO DELAY BUILDING OF HIGHEST SEAS. && .HIGH SURF/COASTAL FLOOD/BEACH EROSION... NO REAL CHANGES TO PREVIOUS THINKING ON THESE TOPICS. WILL NOT GO ANY HIGHER THAN 7 FT ON THE NEARBY COASTAL WATERS TODAY AND EARLY TONIGHT...SO NO NEED FOR ANY HIGH SURF ADVISORY AT THIS TIME. HOWEVER...DEPENDING UPON THE STRENGTH OF THE LOW MOVING IN FROM THE WSW TONIGHT... THERE COULD BE A BRIEF PERIOD WHERE THE SURGING WINDS ALLOW FOR SEAS TO APPROACH 8 FT TONIGHT...ESP ON THE SC WATERS AND WILL CONTINUE TO MONITOR FOR A HIGH SURF ADVISORY. TIDE LEVELS HAVE CHANGED DRAMATICALLY IN THE PAST 24 HOURS...WITH CURRENT TIDES RUNNING ABOVE PREDICTED VALUES. FORTUNATELY THE HIGHER OF THE 2 TIDES TODAY IS EARLY THIS MORNING...AND BY THE TIME WE SEE THE NEXT HIGHER TIDE FRI MORNING THE FLOW IS OFFSHORE. THEREFORE THE RISK OF ANY SHALLOW COASTAL FLOODING APPEARS TO BE LOW. CERTAINLY COULD SEE SOME BEACH EROSION TODAY AND TONIGHT WITH INCREASING ONSHORE WINDS AND BUILDING SEAS AND WILL ADDRESS THIS CONCERN IN THE HWO. && .AVIATION /16Z-12Z/... LOWER CIGS JUST NOW ARRIVING AT TERMS AS LLVL MOISTURE INCREASES. CIGS WILL CONTINUE TO FALL WITH LOWERING INVERSION THIS AFTN AND TONIGHT. WIND FCST DURING THE PERIOD IS TOUGH GIVEN THE UNCERTAIN OSCILLATIONS OF THE FRONTAL BOUNDARY. ONE CERTAINTY IS THE WIND SHEAR. MODERATE TO STRONG S-SW WINDS WILL PREVAIL ABOVE THE INVERSION AND HAVE INCLUDED WIND SHEAR AT BOTH KCHS AND KSAV THRU THE REST OF THE FCST PERIOD. BEST CHANCE FOR HEAVIER PRECIP STILL LOOKS TO BE IN THE LATE AFTN INTO THE EVE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST FRIDAY FOR AMZ330. SMALL CRAFT ADVISORY UNTIL 10 AM EST FRIDAY FOR AMZ352-354. SMALL CRAFT ADVISORY UNTIL 5 PM EST FRIDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR AMZ374. GALE WARNING FROM 10 PM THIS EVENING TO 5 AM EST FRIDAY FOR AMZ374. && $$ JRL ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 347 PM EST THU FEB 1 2007 .SHORT TERM... SEVERAL MINOR CHALLENGES IN THE SHORT TERM PACKAGE. MODELS NOT HANDLING OVERALL PATTERN WELL GIVEN SUBTLE SHORT WAVES AND SHALLOW MOISTURE. HAVE GENERALLY FOLLOWED THE NAM12 AND RUC40 ALONG WITH RADAR AND SATELLITE TRENDS FOR THE SHORT TERM. WATER VAPOR SHOWS POTENT ARCTIC WAVE DIVING SOUTH THROUGH CENTRAL CANADA THIS AFTERNOON. DOWNSTREAM FLOW RESPONDING ALREADY WITH BACKING WINDS AND SOUTHWEST FLOW DEVELOPING AHEAD OF MAIN TROUGH. SEVERAL WEAK SHORT WAVES EMBEDDED IN THIS SOUTHWEST FLOW AND COUPLED WITH LOW LEVEL MOISTURE ARE GENERATING AREAS OF LIGHT SNOW ACROSS THE MISSISSIPPI VALLEY AND GREAT LAKES REGIONS. THE SOUTHWEST FLOW ACROSS LAKE MICHIGAN IS ALSO GENERATING PERSISTENT LAKE EFFECT SNOW BANDS ACROSS MAINLY BERRIEN COUNTY. LATEST RADAR AND SATELLITE SHOWS A SHORT WAVE AND EMBEDDED VORTICITY MAX MOVING THROUGH ILLINOIS THIS AFTERNOON. KLOT AND KILX 88D ALONG WITH SURFACE OBSERVATIONS SHOWING LIGHT SNOW DEVELOPING WITH THIS WAVE. IT SHOULD QUICKLY MOVE NORTHEAST THIS AFTERNOON BUT LOOKS TO GRAZE NORTHWEST INDIANA AND SOUTHWEST MICHIGAN WITH A BRIEF PERIOD OF LIGHT SNOW INTO THIS EVENING. THIS SHOULD ALSO ACT TO ENHANCE LAKE SNOW IN BERRIEN COUNTY THIS EVENING. ANOTHER INCH OR TWO ACCUM POSSIBLE THERE WITH MAYBE UP TO AN INCH AWAY FROM LAKE...MAINLY NORTHWEST INDIANA AND SOUTHWEST LOWER MICHIGAN. ANOTHER STRONGER WAVE MOVING THROUGH ARKANSAS THIS AFTERNOON IS PROGGED BY MODELS TO STAY SOUTHEAST OF OUR AREA LATER TONIGHT. HOWEVER...WATER VAPOR SEEMS TO INDICATE THIS WAVE GETTING LIFTED FURTHER NORTH MUCH QUICKER GIVEN UPSTREAM AMPLIFICATION FROM ARCTIC WAVE. WILL LEAVE LIGHT SNOW MENTION IN ALL AREAS FOR OVERNIGHT AS I SUSPECT WE WILL SEE LIGHT SNOW WITH THIS SYSTEM SPREAD ACROSS CENTRAL AND EASTERN AREAS OVERNIGHT. FINALLY...THE ARCTIC FRONT WILL BLAST ACROSS THE AREA FRIDAY MORNING WITH MORNING HIGHS AND FALLING AFTERNOON TEMPERATURES. 850MB TEMPS CRASH TO NEAR -22C IN THE NORTHWEST BY 00Z/03. INCREASING LOW LEVEL MOISTURE WITH ARCTIC SURGE SHOULD ONCE AGAIN ALLOW FOR LIGHT SNOW TO DEVELOP NEAR SURFACE FRONT. HAVE KEPT POPS IN THE CHANCE CATEGORY GIVEN LITTLE MOISTURE TO WORK WITH BUT HIGH LIQUID TO SNOW RATIOS. MAY SEE HALF INCH AMOUNTS WITH TRACE LIQUID. MID SHIFT CAN INCREASE AS RADAR TRENDS DICTATE BY EARLY MORNING. HAVE USED RUC40 AND NAM12 TEMPS AND WINDS FOR FRIDAY WITH A DOWNWARD ADJUSTMENT AS THEY ARE LIKELY TOO SLOW WITH FALLING TEMPS. WILL ALSO SEE LAKE EFFECT SNOW SHOWERS INCREASE IN INTENSITY ONCE AGAIN FRIDAY AFTERNOON WITH 1 TO 3 INCH ACCUMS POSSIBLE WITH GENERAL WEST TO SOUTHWEST FLOW. NO HEADLINES PLANNED AT THIS TIME AS AMOUNTS WILL BE SPREAD OUT THROUGH THE SHORT TERM PERIOD WITH 2 TO 4 AND LOCAL 5 INCH AMOUNTS EXPECTED. $$ .LONG TERM... POLAR VORTEX OVER HUDSON BAY IS FCST SIMILARLY BY THE MODELS TO MOVE SOUTH ACROSS ONTARIO AND THEN NE ACROSS QUEBEC THIS WEEKEND AND THEN GRADUALLY FILL AND DRIFT SLOWLY EAST TO CANADIAN MARITIMES BY NEXT THU. ECMWF IS SLOWER TO WEAKEN THE UPPER LOW NEXT WEEK AND IS PREFERRED IN THIS RESPECT OVER THE GFS AS SUCH A STRONG AND LARGE CIRCULATION WILL BE SLOW TO BREAK DOWN. OTRWS, OVER THE WEEKEND THE MODELS ARE IN FAIRLY GOOD AGREEMENT. ARCTIC AIR EXPECTED TO BE ADVECTING INTO THE CWA AT START OF THE PERIOD FRI NGT. WNW LOW LEVEL FLOW SHOULD RESULT IN SNOW SHOWERS ACRS SRN MI AND ADJACENT COUNTIES IN NRN INDIANA AT LEAST THROUGH THE EVENING WITH A WK SHRTWV PASSAGE SUPPORTING GOING CHC POPS JUST TO SOUTH OF THIS AREA. ALTHOUGH LAKE INDUCED INSTABILITY WILL BE EXTREME, KEPT AMOUNTS IN THE 1-3" RANGE DUE TO LOW INVERSION HEIGHT/DENDRITIC GROWTH ZONE AND SHALLOW MOISTURE. ON SATURDAY A REINFORCING SHOT OF THE ARCTIC AIR FCST BY BOTH THE GFS/NAM TO MOVE INTO THE AREA. SOME TIMING DIFFERENCES AS GFS ABOUT 6HRS FASTER TO MOVE THIS CDFNT THROUGH THE AREA. SIDED WITH THE SLOWER NAM TIMING FOR NOW...KEEPING HIGHS IN THE TEENS WITH WK WAA EXPECTED AT DURING THE MORNING WITH CAA RETURNING IN THE AFTN. FAIRLY STRONG LOW LEVEL CONVERGENCE ALONG THIS FRONT SHOULD SQUEEZE OUT SOME LIGHT SNOW SATURDAY, ESPECIALLY ACROSS NRN PORTIONS OF THE CWA WHERE THERE WILL BE SOME LAKE ENHANCEMENT. WINDS WILL BECOME BRISK ALONG AND BEHIND THE ARCTIC FRONT. THIS MAY LEAD TO SOME BLOWING/DRIFTING SNOW PROBLEMS SAT NGT BUT OPTED TO LEAVE CATEGORICAL MENTION OF THIS OUT OF ZFP ATTM. BY SUNDAY MORNING, 850MB TEMPS FCST TO FALL TO AROUND -25C. THIS SHOULD RESULT IN SFC TEMPS FALLING BELOW ZERO OVER ALL OF THE CWA WITH THE EXCEPTION OF AREA NEAR LM WITH WIND CHILL READINGS POSSIBLY BLO ADVISORY CRITERIA. THIS AIRMASS LOOKS VERY SIMILAR TO THE ONE WHICH SET RECORD LOWS HERE IN FEB96 (WITH 850MB TEMPS AROUND -25C), AND AS SUCH CAN SEE FURTHER DOWNSIDE POTENTIAL FOR TEMPS EARLY NEXT WEEK. WITH W-WNW FLOW CONTINUING THROUGH SUNDAY NIGHT, SNOW SHOWERS WILL LIKELY CONTINUE OVER SW MI AND ADJACENT AREAS OF NRN INDIANA. LIMITING FACTORS MENTIONED PREVIOUSLY MAY KEEP SNOW ACCUMS FROM GETTING HEAVY IN ANY GIVEN PERIOD, BUT WILL LIKELY BE PERSISTENT ACCUMS. GFS INDICATING FLOW WILL VEER MORE NWLY ON MONDAY AS A WK TROF MOVES THROUGH THE AREA WHICH COULD RESULT IN MORE SGFNT LAKE EFFECT SNOWS. ARCTIC AIR WILL REMAIN ENTRENCHED OVER THE AREA EARLY NEXT WEEK WITH SLOW MODIFICATION EXPECTED BY THURSDAY. LAKE EFFECT SNOW CHANCES WILL CONTINUE THROUGH THIS PERIOD WITH POPS GRADUALLY PULLED NORTHWARD AS LOW LEVEL WINDS SLOWLY BACK WITH PASSAGE OF ARCTIC HIGH. 12Z GFS IS SLOWER TO MOVE THE HIGH THROUGH, CONTINUING NW FLOW THROUGH THU. FOR NOW WENT DRY ON DAY7 BUT IF THIS SOLUTION PERSISTS WOULD HAVE TO EXTEND LAKE EFFECT SNOW SHOWERS LONGER. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...LASHLEY LONG TERM....TAYLOR in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 347 PM EST THU FEB 1 2007 .SHORT TERM... SEVERAL MINOR CHALLENGES IN THE SHORT TERM PACKAGE. MODELS NOT HANDLING OVERALL PATTERN WELL GIVEN SUBTLE SHORT WAVES AND SHALLOW MOISTURE. HAVE GENERALLY FOLLOWED THE NAM12 AND RUC40 ALONG WITH RADAR AND SATELLITE TRENDS FOR THE SHORT TERM. WATER VAPOR SHOWS POTENT ARCTIC WAVE DIVING SOUTH THROUGH CENTRAL CANADA THIS AFTERNOON. DOWNSTREAM FLOW RESPONDING ALREADY WITH BACKING WINDS AND SOUTHWEST FLOW DEVELOPING AHEAD OF MAIN TROUGH. SEVERAL WEAK SHORT WAVES EMBEDDED IN THIS SOUTHWEST FLOW AND COUPLED WITH LOW LEVEL MOISTURE ARE GENERATING AREAS OF LIGHT SNOW ACROSS THE MISSISSIPPI VALLEY AND GREAT LAKES REGIONS. THE SOUTHWEST FLOW ACROSS LAKE MICHIGAN IS ALSO GENERATING PERSISTENT LAKE EFFECT SNOW BANDS ACROSS MAINLY BERRIEN COUNTY. LATEST RADAR AND SATELLITE SHOWS A SHORT WAVE AND EMBEDDED VORTICITY MAX MOVING THROUGH ILLINOIS THIS AFTERNOON. KLOT AND KILX 88D ALONG WITH SURFACE OBSERVATIONS SHOWING LIGHT SNOW DEVELOPING WITH THIS WAVE. IT SHOULD QUICKLY MOVE NORTHEAST THIS AFTERNOON BUT LOOKS TO GRAZE NORTHWEST INDIANA AND SOUTHWEST MICHIGAN WITH A BRIEF PERIOD OF LIGHT SNOW INTO THIS EVENING. THIS SHOULD ALSO ACT TO ENHANCE LAKE SNOW IN BERRIEN COUNTY THIS EVENING. ANOTHER INCH OR TWO ACCUM POSSIBLE THERE WITH MAYBE UP TO AN INCH AWAY FROM LAKE...MAINLY NORTHWEST INDIANA AND SOUTHWEST LOWER MICHIGAN. ANOTHER STRONGER WAVE MOVING THROUGH ARKANSAS THIS AFTERNOON IS PROGGED BY MODELS TO STAY SOUTHEAST OF OUR AREA LATER TONIGHT. HOWEVER...WATER VAPOR SEEMS TO INDICATE THIS WAVE GETTING LIFTED FURTHER NORTH MUCH QUICKER GIVEN UPSTREAM AMPLIFICATION FROM ARCTIC WAVE. WILL LEAVE LIGHT SNOW MENTION IN ALL AREAS FOR OVERNIGHT AS I SUSPECT WE WILL SEE LIGHT SNOW WITH THIS SYSTEM SPREAD ACROSS CENTRAL AND EASTERN AREAS OVERNIGHT. FINALLY...THE ARCTIC FRONT WILL BLAST ACROSS THE AREA FRIDAY MORNING WITH MORNING HIGHS AND FALLING AFTERNOON TEMPERATURES. 850MB TEMPS CRASH TO NEAR -22C IN THE NORTHWEST BY 00Z/03. INCREASING LOW LEVEL MOISTURE WITH ARCTIC SURGE SHOULD ONCE AGAIN ALLOW FOR LIGHT SNOW TO DEVELOP NEAR SURFACE FRONT. HAVE KEPT POPS IN THE CHANCE CATEGORY GIVEN LITTLE MOISTURE TO WORK WITH BUT HIGH LIQUID TO SNOW RATIOS. MAY SEE HALF INCH AMOUNTS WITH TRACE LIQUID. MID SHIFT CAN INCREASE AS RADAR TRENDS DICTATE BY EARLY MORNING. HAVE USED RUC40 AND NAM12 TEMPS AND WINDS FOR FRIDAY WITH A DOWNWARD ADJUSTMENT AS THEY ARE LIKELY TOO SLOW WITH FALLING TEMPS. WILL ALSO SEE LAKE EFFECT SNOW SHOWERS INCREASE IN INTENSITY ONCE AGAIN FRIDAY AFTERNOON WITH 1 TO 3 INCH ACCUMS POSSIBLE WITH GENERAL WEST TO SOUTHWEST FLOW. NO HEADLINES PLANNED AT THIS TIME AS AMOUNTS WILL BE SPREAD OUT THROUGH THE SHORT TERM PERIOD WITH 2 TO 4 AND LOCAL 5 INCH AMOUNTS EXPECTED. $$ .LONG TERM... POLAR VORTEX OVER HUDSON BAY IS FCST SIMILARLY BY THE MODELS TO MOVE SOUTH ACROSS ONTARIO AND THEN NE ACROSS QUEBEC THIS WEEKEND AND THEN GRADUALLY FILL AND DRIFT SLOWLY EAST TO CANADIAN MARITIMES BY NEXT THU. ECMWF IS SLOWER TO WEAKEN THE UPPER LOW NEXT WEEK AND IS PREFERRED IN THIS RESPECT OVER THE GFS AS SUCH A STRONG AND LARGE CIRCULATION WILL BE SLOW TO BREAK DOWN. OTRWS, OVER THE WEEKEND THE MODELS ARE IN FAIRLY GOOD AGREEMENT. ARCTIC AIR EXPECTED TO BE ADVECTING INTO THE CWA AT START OF THE PERIOD FRI NGT. WNW LOW LEVEL FLOW SHOULD RESULT IN SNOW SHOWERS ACRS SRN MI AND ADJACENT COUNTIES IN NRN INDIANA AT LEAST THROUGH THE EVENING WITH A WK SHRTWV PASSAGE SUPPORTING GOING CHC POPS JUST TO SOUTH OF THIS AREA. ALTHOUGH LAKE INDUCED INSTABILITY WILL BE EXTREME, KEPT AMOUNTS IN THE 1-3" RANGE DUE TO LOW INVERSION HEIGHT/DENDRITIC GROWTH ZONE AND SHALLOW MOISTURE. ON SATURDAY A REINFORCING SHOT OF THE ARCTIC AIR FCST BY BOTH THE GFS/NAM TO MOVE INTO THE AREA. SOME TIMING DIFFERENCES AS GFS ABOUT 6HRS FASTER TO MOVE THIS CDFNT THROUGH THE AREA. SIDED WITH THE SLOWER NAM TIMING FOR NOW...KEEPING HIGHS IN THE TEENS WITH WK WAA EXPECTED AT DURING THE MORNING WITH CAA RETURNING IN THE AFTN. FAIRLY STRONG LOW LEVEL CONVERGENCE ALONG THIS FRONT SHOULD SQUEEZE OUT SOME LIGHT SNOW SATURDAY, ESPECIALLY ACROSS NRN PORTIONS OF THE CWA WHERE THERE WILL BE SOME LAKE ENHANCEMENT. WINDS WILL BECOME BRISK ALONG AND BEHIND THE ARCTIC FRONT. THIS MAY LEAD TO SOME BLOWING/DRIFTING SNOW PROBLEMS SAT NGT BUT OPTED TO LEAVE CATEGORICAL MENTION OF THIS OUT OF ZFP ATTM. BY SUNDAY MORNING, 850MB TEMPS FCST TO FALL TO AROUND -25C. THIS SHOULD RESULT IN SFC TEMPS FALLING BELOW ZERO OVER ALL OF THE CWA WITH THE EXCEPTION OF AREA NEAR LM WITH WIND CHILL READINGS POSSIBLY BLO ADVISORY CRITERIA. THIS AIRMASS LOOKS VERY SIMILAR TO THE ONE WHICH SET RECORD LOWS HERE IN FEB96 (WITH 850MB TEMPS AROUND -25C), AND AS SUCH CAN SEE FURTHER DOWNSIDE POTENTIAL FOR TEMPS EARLY NEXT WEEK. WITH W-WNW FLOW CONTINUING THROUGH SUNDAY NIGHT, SNOW SHOWERS WILL LIKELY CONTINUE OVER SW MI AND ADJACENT AREAS OF NRN INDIANA. LIMITING FACTORS MENTIONED PREVIOUSLY MAY KEEP SNOW ACCUMS FROM GETTING HEAVY IN ANY GIVEN PERIOD, BUT WILL LIKELY BE PERSISTENT ACCUMS. GFS INDICATING FLOW WILL VEER MORE NWLY ON MONDAY AS A WK TROF MOVES THROUGH THE AREA WHICH COULD RESULT IN MORE SGFNT LAKE EFFECT SNOWS. ARCTIC AIR WILL REMAIN ENTRENCHED OVER THE AREA EARLY NEXT WEEK WITH SLOW MODIFICATION EXPECTED BY THURSDAY. LAKE EFFECT SNOW CHANCES WILL CONTINUE THROUGH THIS PERIOD WITH POPS GRADUALLY PULLED NORTHWARD AS LOW LEVEL WINDS SLOWLY BACK WITH PASSAGE OF ARCTIC HIGH. 12Z GFS IS SLOWER TO MOVE THE HIGH THROUGH, CONTINUING NW FLOW THROUGH THU. FOR NOW WENT DRY ON DAY7 BUT IF THIS SOLUTION PERSISTS WOULD HAVE TO EXTEND LAKE EFFECT SNOW SHOWERS LONGER. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...LASHLEY LONG TERM....TAYLOR in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 1048 AM CST THU FEB 1 2007 .UPDATE... ISSUING A QUICK FORECAST UPDATE FOR TEMPS AND SKY TRENDS. CLEARING LINE IS WORKING THROUGH THE CWA THIS MORNING...AND AT 1630Z WAS ROUGHLY ALONG A LINE FROM KSQI TO KIRK. AFTER A COLD START THIS MORNING AND WITH COLD AIR ADVECTION FOR MUCH OF TODAY...HAVE LOWERED MAX TEMP FORECAST DESPITE SUNNY SKIES. CLOUDS AHEAD OF NEXT SHORTWAVE/SURFACE COLD FRONT WILL REACH NRN CWA THIS AFTERNOON...PUSHING THROUGH THE REST OF THE CWA OVERNIGHT. STILL EXPECT FLURRIES BENEATH STRATUS DECK AS IT WORKS EWD THROUGH THE REST OF THE MORNING AND INTO THE EARLY AFTERNOON. HAVE LOWERED MIN TEMP FORECAST TONIGHT AND LIKELY WILL NEED TO LOWER IT FURTHER IN THE AFTERNOON FORECAST PACKAGE AS CLEAR SLOT WILL ALLOW A QUICK DROP IN TEMPS...AND MIN TEMP FORECASTS HAVE PERSISTENLY BEEN TOO WARM THIS WEEK. ..MAYES.. && .PREVIOUS DISCUSSION...ISSUED AT 330 AM... COLD FRONT WAS JUST ENTERING NWRN CWA EARLY THIS MORNING. NARROW BAND OF LIGHT...ACCUMULATING...SNOW AHEAD OF THE FRONT WAS STILL OVER THE FAR EASTERN COUNTIES EARLY THIS MORNING WITH SCATTERED FLURRIES EXTENDING BACK TO THE WEST. LOW CLOUDS HAVE SCATTERED OUT CONSIDERABLY WEST OF THE MISSISSIPPI RIVER AND NORTH OF I80 WITH DEFINITE CLEARING LINE FROM KMCW TO JUST WEST OF KDSM AT 09Z. LITTLE CHANGE WAS NOTED IN THE UPPER AIR PATTERN FROM THE LAST SEVERAL DAYS. REGION REMAINS UNDER BROAD MID LEVEL TROF WITH SHARP H5 RIDGE ANCHORED JUST OFF THE WEST COAST. S/W TROF ASSOCIATED WITH THE COLD FRONT OVER THE REGION THIS MORNING...EXTENDED FROM MN SW THROUGH WRN NE AT 00Z. ANOTHER POTENT S/W WAS LOCATED UPSTREAM OVER NRN SASKATCHEWAN AND ALBERTA. && .SHORT TERM...TODAY AND TONIGHT... SHORT RANGE MODELS ARE IN GOOD AGREEMENT WITH RAPID SUCCESSION OF FRONTS MOVING THROUGH THE CWA TODAY AND TONIGHT. FRONT CURRENTLY CROSSING CWA SHOULD BE EAST OF THE AREA THIS MORNING WITH ASSOCIATED S/W TROF REACHING THE MS RIVER BY MIDDAY. WEAK SURFACE RIDGE TO CROSS CWA THIS AFTERNOON...THEN RETURN FLOW DEVELOPS FOR BRIEF TIME THIS EVENING INTO EARLY FRIDAY MORNING. NEXT S/W DROPS INTO WRN IA BY 12Z FRIDAY WITH SURFACE COLD FRONT PROGGED TO BE JUST WEST OF THE MS RIVER. INITIAL CHALLENGE WILL CONCERN CLOUD TRENDS TODAY WITH BACK OF EDGE OF LOW CLOUDS ALREADY INTO CENTRAL IA...WELL EAST OF NAM/GFS SHOW BACK EDGE OF LOW LEVEL RH THIS MORNING. BASED ON CURRENT TRENDS AND MORE REALISTIC 925 RH PROGS OFF THE RUC...HAVE DECREASED SKY COVER OVER CWA CONSIDERABLY THIS MORNING...BEFORE HIGH CLOUDS AHEAD OF NEXT S/W SWEEP OVER CWA THIS AFTERNOON. MAX TEMPS TODAY OFFER ANOTHER CHALLENGE WITH LESS CLOUDS THAN MOS SHOWS FAVORING WARMER TEMPS. HOWEVER LIGHT WINDS IN SURFACE RIDGE AND FRESH DUSTING OF NEW SNOW ALONG WITH LOW LEVEL CAA MOST OF THE DAY POINTING TO COLDER TEMPS SHOULD OFFSET ANY ADDITIONAL SUN. KEPT MAX TEMPS AT OR JUST BELOW COLDER MET GUIDANCE. NEXT S/W PROGGED TO MOVE THROUGH CWA BY FRIDAY. QVECTOR CONVERGENCE SUGGESTS BEST SYNOPTIC FORCING AHEAD OF TROF WILL STAY TO OUR NORTH...SO KEPT LOW CHANCE POPS GOING FOR TONIGHT. SURFACE FRONT SHOULD BE ENTERING NORTHWEST CWA AFTER 09Z WITH STRONG NW WINDS KICKING RIGHT AFTER FROPA. WITH HALF INCH TO INCH OF FLUFF THAT FELL WEDNESDAY EVENING ...FELT THAT BLSN CURRENTLY IN GRIDS WAS WORTH KEEPING. ..DLF.. .LONGER TERM...FRIDAY THROUGH NEXT WEDNESDAY...A RATHER VIGOROUS VORT COMPLEX NOW SEEN ON W/V IMAGERY WEST OF HUDSON BAY...IS STILL PROGGED BY LATEST SUITE OF SHORT RANGE MODEL RUNS TO ROTATE DOWN ACRS THE AREA IN STEEPENING CYCLONIC UPPER FLOW ON FRI AS POLAR VORTEX BECOMES ENTRENCHED OVER WESTERN ONTARIO. LOW TO MID LEVEL SATURATION FOR MUCH OF ANYTHING TO GET WRUNG OUT BY THE INCOMING LIFT OTHER THAN SOME FLURRIES STILL AT QUESTION...BUT LATEST FCST PROFILES/SOUNDINGS SHOW ENOUGH FOR MORE OF A LIGHT SNOW AS OPPOSED TO SPORADIC FLURRIES THROUGH AT LEAST MIDDAY ACRS THE NORTHEAST 2/3`S OF THE FCST AREA. WITH EXPECTED MOMENTUM WIND SURGE/ABOVE THAT ADVERTISED BY THE MODELS/ BEHIND FROPA AS ARCTIC FRONT PLOWS ITS WAY THRU AND EAST OF THE AREA FRI MORNING...SOME BLOWING OF THE POWDER/ THAT COULD ACCUMULATE FROM .5 TO AN INCH BY LATE FRI MORNING/ ACRS ROADS AND OPEN FIELDS WILL BE LIKELY AND WILL INCLUDE WORDING FOR THIS IN THE GRIDS. AS FOR TEMPS...MAYBE A FEW DEGREES RECOVER FROM 12Z VALUES DURING LATE FRI MORNING AND MIDDAY...BUT EXPECT A THERMAL DROP OFF AS THE AFTERNOON PROGRESSES AS YET ANOTHER -20 C AND COLDER H85 MB COLD POOL SEEPS RIGHT OVER THE FCST AREA. WIND CHILLS DURING THE DAY DIP INTO THE MID TO UPPER TEENS BELOW ZERO FOR AWHILE IN THE NORTHWESTERN CWA...BUT DON/T QUITE REACH ADVISORY CRITERIA. THAT WILL CHANGE BY FRI NIGHT AS WINDS AND STOUT CAA MAINTAIN. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED LATER FRI NIGHT AND INTO SAT FOR MUCH OF THE DVN CWA. AS FOR ANOTHER CLIPPER SKIRTING DOWN ACRS THE AREA FRI NIGHT...THE GFS IS AGAIN THE MOST BULLISH WITH LIFT AND SATURATION AND LOOKS OVERDONE...BUT WILL KEEP CHC POPS FOR LIGHT SNOW AFTER MIDNIGHT AND INTO EARLY SAT MORNING. OTHERWISE OCCASIONAL FLURRIES WILL ACCOMPANY AND CLOUD COVER THAT SWEEPS ON THRU IN STEEP NORTHWEST FLOW WITH ANY SATURATION EASILY IN THE -10 C OR COLDER RANGE. 3RD NIGHT IN A ROW WHERE LATEST RUN AND ACCEPTED/FAVORED MEDIUM RANGE MODEL RUNS ADVERTISE MERIDIONAL FETCH FROM NORTHWEST OF THE HUDSON BAY REGION- ARCTIC BRINGING NEAR -30 C H85 COLD POOL DOWN NEAR THE FCST AREA SAT NIGHT INTO SUN. WILL CONTINUE TO MAKE MINOR TWEAKS/DOWN TRENDS IN BOTH HIGHS AND LOWS OVER THE WEEKEND...WITH THE CONTINUING THOUGHT OF AT LEAST SOME -20 F VALUES BEING REACHED IN PORTIONS OF THE FCST AREA EITHER SUNDAY MORNING OR MONDAY LOOKING ON TARGET. ONLY WEAKENING SFC WINDS WITH SOME LLVL RIDGING MAKING ITS WAY ACRS THE AREA LATER SAT NIGHT INTO SUNDAY MAY PRECLUDE A WIND CHILL WARNING FOR THAT TIME PERIOD...BUT STILL NOT OUT OF THE QUESTION. NO CHANGES INTO EARLY NEXT WEEK FOR NOW. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ MAYES ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 1048 AM CST THU FEB 1 2007 .UPDATE... ISSUING A QUICK FORECAST UPDATE FOR TEMPS AND SKY TRENDS. CLEARING LINE IS WORKING THROUGH THE CWA THIS MORNING...AND AT 1630Z WAS ROUGHLY ALONG A LINE FROM KSQI TO KIRK. AFTER A COLD START THIS MORNING AND WITH COLD AIR ADVECTION FOR MUCH OF TODAY...HAVE LOWERED MAX TEMP FORECAST DESPITE SUNNY SKIES. CLOUDS AHEAD OF NEXT SHORTWAVE/SURFACE COLD FRONT WILL REACH NRN CWA THIS AFTERNOON...PUSHING THROUGH THE REST OF THE CWA OVERNIGHT. STILL EXPECT FLURRIES BENEATH STRATUS DECK AS IT WORKS EWD THROUGH THE REST OF THE MORNING AND INTO THE EARLY AFTERNOON. HAVE LOWERED MIN TEMP FORECAST TONIGHT AND LIKELY WILL NEED TO LOWER IT FURTHER IN THE AFTERNOON FORECAST PACKAGE AS CLEAR SLOT WILL ALLOW A QUICK DROP IN TEMPS...AND MIN TEMP FORECASTS HAVE PERSISTENLY BEEN TOO WARM THIS WEEK. ..MAYES.. && .PREVIOUS DISCUSSION...ISSUED AT 330 AM... COLD FRONT WAS JUST ENTERING NWRN CWA EARLY THIS MORNING. NARROW BAND OF LIGHT...ACCUMULATING...SNOW AHEAD OF THE FRONT WAS STILL OVER THE FAR EASTERN COUNTIES EARLY THIS MORNING WITH SCATTERED FLURRIES EXTENDING BACK TO THE WEST. LOW CLOUDS HAVE SCATTERED OUT CONSIDERABLY WEST OF THE MISSISSIPPI RIVER AND NORTH OF I80 WITH DEFINITE CLEARING LINE FROM KMCW TO JUST WEST OF KDSM AT 09Z. LITTLE CHANGE WAS NOTED IN THE UPPER AIR PATTERN FROM THE LAST SEVERAL DAYS. REGION REMAINS UNDER BROAD MID LEVEL TROF WITH SHARP H5 RIDGE ANCHORED JUST OFF THE WEST COAST. S/W TROF ASSOCIATED WITH THE COLD FRONT OVER THE REGION THIS MORNING...EXTENDED FROM MN SW THROUGH WRN NE AT 00Z. ANOTHER POTENT S/W WAS LOCATED UPSTREAM OVER NRN SASKATCHEWAN AND ALBERTA. && .SHORT TERM...TODAY AND TONIGHT... SHORT RANGE MODELS ARE IN GOOD AGREEMENT WITH RAPID SUCCESSION OF FRONTS MOVING THROUGH THE CWA TODAY AND TONIGHT. FRONT CURRENTLY CROSSING CWA SHOULD BE EAST OF THE AREA THIS MORNING WITH ASSOCIATED S/W TROF REACHING THE MS RIVER BY MIDDAY. WEAK SURFACE RIDGE TO CROSS CWA THIS AFTERNOON...THEN RETURN FLOW DEVELOPS FOR BRIEF TIME THIS EVENING INTO EARLY FRIDAY MORNING. NEXT S/W DROPS INTO WRN IA BY 12Z FRIDAY WITH SURFACE COLD FRONT PROGGED TO BE JUST WEST OF THE MS RIVER. INITIAL CHALLENGE WILL CONCERN CLOUD TRENDS TODAY WITH BACK OF EDGE OF LOW CLOUDS ALREADY INTO CENTRAL IA...WELL EAST OF NAM/GFS SHOW BACK EDGE OF LOW LEVEL RH THIS MORNING. BASED ON CURRENT TRENDS AND MORE REALISTIC 925 RH PROGS OFF THE RUC...HAVE DECREASED SKY COVER OVER CWA CONSIDERABLY THIS MORNING...BEFORE HIGH CLOUDS AHEAD OF NEXT S/W SWEEP OVER CWA THIS AFTERNOON. MAX TEMPS TODAY OFFER ANOTHER CHALLENGE WITH LESS CLOUDS THAN MOS SHOWS FAVORING WARMER TEMPS. HOWEVER LIGHT WINDS IN SURFACE RIDGE AND FRESH DUSTING OF NEW SNOW ALONG WITH LOW LEVEL CAA MOST OF THE DAY POINTING TO COLDER TEMPS SHOULD OFFSET ANY ADDITIONAL SUN. KEPT MAX TEMPS AT OR JUST BELOW COLDER MET GUIDANCE. NEXT S/W PROGGED TO MOVE THROUGH CWA BY FRIDAY. QVECTOR CONVERGENCE SUGGESTS BEST SYNOPTIC FORCING AHEAD OF TROF WILL STAY TO OUR NORTH...SO KEPT LOW CHANCE POPS GOING FOR TONIGHT. SURFACE FRONT SHOULD BE ENTERING NORTHWEST CWA AFTER 09Z WITH STRONG NW WINDS KICKING RIGHT AFTER FROPA. WITH HALF INCH TO INCH OF FLUFF THAT FELL WEDNESDAY EVENING ...FELT THAT BLSN CURRENTLY IN GRIDS WAS WORTH KEEPING. ..DLF.. .LONGER TERM...FRIDAY THROUGH NEXT WEDNESDAY...A RATHER VIGOROUS VORT COMPLEX NOW SEEN ON W/V IMAGERY WEST OF HUDSON BAY...IS STILL PROGGED BY LATEST SUITE OF SHORT RANGE MODEL RUNS TO ROTATE DOWN ACRS THE AREA IN STEEPENING CYCLONIC UPPER FLOW ON FRI AS POLAR VORTEX BECOMES ENTRENCHED OVER WESTERN ONTARIO. LOW TO MID LEVEL SATURATION FOR MUCH OF ANYTHING TO GET WRUNG OUT BY THE INCOMING LIFT OTHER THAN SOME FLURRIES STILL AT QUESTION...BUT LATEST FCST PROFILES/SOUNDINGS SHOW ENOUGH FOR MORE OF A LIGHT SNOW AS OPPOSED TO SPORADIC FLURRIES THROUGH AT LEAST MIDDAY ACRS THE NORTHEAST 2/3`S OF THE FCST AREA. WITH EXPECTED MOMENTUM WIND SURGE/ABOVE THAT ADVERTISED BY THE MODELS/ BEHIND FROPA AS ARCTIC FRONT PLOWS ITS WAY THRU AND EAST OF THE AREA FRI MORNING...SOME BLOWING OF THE POWDER/ THAT COULD ACCUMULATE FROM .5 TO AN INCH BY LATE FRI MORNING/ ACRS ROADS AND OPEN FIELDS WILL BE LIKELY AND WILL INCLUDE WORDING FOR THIS IN THE GRIDS. AS FOR TEMPS...MAYBE A FEW DEGREES RECOVER FROM 12Z VALUES DURING LATE FRI MORNING AND MIDDAY...BUT EXPECT A THERMAL DROP OFF AS THE AFTERNOON PROGRESSES AS YET ANOTHER -20 C AND COLDER H85 MB COLD POOL SEEPS RIGHT OVER THE FCST AREA. WIND CHILLS DURING THE DAY DIP INTO THE MID TO UPPER TEENS BELOW ZERO FOR AWHILE IN THE NORTHWESTERN CWA...BUT DON/T QUITE REACH ADVISORY CRITERIA. THAT WILL CHANGE BY FRI NIGHT AS WINDS AND STOUT CAA MAINTAIN. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED LATER FRI NIGHT AND INTO SAT FOR MUCH OF THE DVN CWA. AS FOR ANOTHER CLIPPER SKIRTING DOWN ACRS THE AREA FRI NIGHT...THE GFS IS AGAIN THE MOST BULLISH WITH LIFT AND SATURATION AND LOOKS OVERDONE...BUT WILL KEEP CHC POPS FOR LIGHT SNOW AFTER MIDNIGHT AND INTO EARLY SAT MORNING. OTHERWISE OCCASIONAL FLURRIES WILL ACCOMPANY AND CLOUD COVER THAT SWEEPS ON THRU IN STEEP NORTHWEST FLOW WITH ANY SATURATION EASILY IN THE -10 C OR COLDER RANGE. 3RD NIGHT IN A ROW WHERE LATEST RUN AND ACCEPTED/FAVORED MEDIUM RANGE MODEL RUNS ADVERTISE MERIDIONAL FETCH FROM NORTHWEST OF THE HUDSON BAY REGION- ARCTIC BRINGING NEAR -30 C H85 COLD POOL DOWN NEAR THE FCST AREA SAT NIGHT INTO SUN. WILL CONTINUE TO MAKE MINOR TWEAKS/DOWN TRENDS IN BOTH HIGHS AND LOWS OVER THE WEEKEND...WITH THE CONTINUING THOUGHT OF AT LEAST SOME -20 F VALUES BEING REACHED IN PORTIONS OF THE FCST AREA EITHER SUNDAY MORNING OR MONDAY LOOKING ON TARGET. ONLY WEAKENING SFC WINDS WITH SOME LLVL RIDGING MAKING ITS WAY ACRS THE AREA LATER SAT NIGHT INTO SUNDAY MAY PRECLUDE A WIND CHILL WARNING FOR THAT TIME PERIOD...BUT STILL NOT OUT OF THE QUESTION. NO CHANGES INTO EARLY NEXT WEEK FOR NOW. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ MAYES ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 330 AM CST THU FEB 1 2007 .SYNOPSIS... COLD FRONT WAS JUST ENTERING NWRN CWA EARLY THIS MORNING. NARROW BAND OF LIGHT...ACCUMULATING...SNOW AHEAD OF THE FRONT WAS STILL OVER THE FAR EASTERN COUNTIES EARLY THIS MORNING WITH SCATTERED FLURRIES EXTENDING BACK TO THE WEST. LOW CLOUDS HAVE SCATTERED OUT CONSIDERABLY WEST OF THE MISSISSIPPI RIVER AND NORTH OF I80 WITH DEFINITE CLEARING LINE FROM KMCW TO JUST WEST OF KDSM AT 09Z. LITTLE CHANGE WAS NOTED IN THE UPPER AIR PATTERN FROM THE LAST SEVERAL DAYS. REGION REMAINS UNDER BROAD MID LEVEL TROF WITH SHARP H5 RIDGE ANCHORED JUST OFF THE WEST COAST. S/W TROF ASSOCIATED WITH THE COLD FRONT OVER THE REGION THIS MORNING...EXTENDED FROM MN SW THROUGH WRN NE AT 00Z. ANOTHER POTENT S/W WAS LOCATED UPSTREAM OVER NRN SASKATCHEWAN AND ALBERTA. && .SHORT TERM...TODAY AND TONIGHT... SHORT RANGE MODELS ARE IN GOOD AGREEMENT WITH RAPID SUCCESSION OF FRONTS MOVING THROUGH THE CWA TODAY AND TONIGHT. FRONT CURRENTLY CROSSING CWA SHOULD BE EAST OF THE AREA THIS MORNING WITH ASSOCIATED S/W TROF REACHING THE MS RIVER BY MIDDAY. WEAK SURFACE RIDGE TO CROSS CWA THIS AFTERNOON...THEN RETURN FLOW DEVELOPS FOR BRIEF TIME THIS EVENING INTO EARLY FRIDAY MORNING. NEXT S/W DROPS INTO WRN IA BY 12Z FRIDAY WITH SURFACE COLD FRONT PROGGED TO BE JUST WEST OF THE MS RIVER. INITIAL CHALLENGE WILL CONCERN CLOUD TRENDS TODAY WITH BACK OF EDGE OF LOW CLOUDS ALREADY INTO CENTRAL IA...WELL EAST OF NAM/GFS SHOW BACK EDGE OF LOW LEVEL RH THIS MORNING. BASED ON CURRENT TRENDS AND MORE REALISTIC 925 RH PROGS OFF THE RUC...HAVE DECREASED SKY COVER OVER CWA CONSIDERABLY THIS MORNING...BEFORE HIGH CLOUDS AHEAD OF NEXT S/W SWEEP OVER CWA THIS AFTERNOON. MAX TEMPS TODAY OFFER ANOTHER CHALLENGE WITH LESS CLOUDS THAN MOS SHOWS FAVORING WARMER TEMPS. HOWEVER LIGHT WINDS IN SURFACE RIDGE AND FRESH DUSTING OF NEW SNOW ALONG WITH LOW LEVEL CAA MOST OF THE DAY POINTING TO COLDER TEMPS SHOULD OFFSET ANY ADDITIONAL SUN. KEPT MAX TEMPS AT OR JUST BELOW COLDER MET GUIDANCE. NEXT S/W PROGGED TO MOVE THROUGH CWA BY FRIDAY. QVECTOR CONVERGENCE SUGGESTS BEST SYNOPTIC FORCING AHEAD OF TROF WILL STAY TO OUR NORTH...SO KEPT LOW CHANCE POPS GOING FOR TONIGHT. SURFACE FRONT SHOULD BE ENTERING NORTHWEST CWA AFTER 09Z WITH STRONG NW WINDS KICKING RIGHT AFTER FROPA. WITH HALF INCH TO INCH OF FLUFF THAT FELL WEDNESDAY EVENING ...FELT THAT BLSN CURRENTLY IN GRIDS WAS WORTH KEEPING. ..DLF.. .LONGER TERM...FRIDAY THROUGH NEXT WEDNESDAY...A RATHER VIGOROUS VORT COMPLEX NOW SEEN ON W/V IMAGERY WEST OF HUDSON BAY...IS STILL PROGGED BY LATEST SUITE OF SHORT RANGE MODEL RUNS TO ROTATE DOWN ACRS THE AREA IN STEEPENING CYCLONIC UPPER FLOW ON FRI AS POLAR VORTEX BECOMES ENTRENCHED OVER WESTERN ONTARIO. LOW TO MID LEVEL SATURATION FOR MUCH OF ANYTHING TO GET WRUNG OUT BY THE INCOMING LIFT OTHER THAN SOME FLURRIES STILL AT QUESTION...BUT LATEST FCST PROFILES/SOUNDINGS SHOW ENOUGH FOR MORE OF A LIGHT SNOW AS OPPOSED TO SPORADIC FLURRIES THROUGH AT LEAST MIDDAY ACRS THE NORTHEAST 2/3`S OF THE FCST AREA. WITH EXPECTED MOMENTUM WIND SURGE/ABOVE THAT ADVERTISED BY THE MODELS/ BEHIND FROPA AS ARCTIC FRONT PLOWS ITS WAY THRU AND EAST OF THE AREA FRI MORNING...SOME BLOWING OF THE POWDER/ THAT COULD ACCUMULATE FROM .5 TO AN INCH BY LATE FRI MORNING/ ACRS ROADS AND OPEN FIELDS WILL BE LIKELY AND WILL INCLUDE WORDING FOR THIS IN THE GRIDS. AS FOR TEMPS...MAYBE A FEW DEGREES RECOVER FROM 12Z VALUES DURING LATE FRI MORNING AND MIDDAY...BUT EXPECT A THERMAL DROP OFF AS THE AFTERNOON PROGRESSES AS YET ANOTHER -20 C AND COLDER H85 MB COLD POOL SEEPS RIGHT OVER THE FCST AREA. WIND CHILLS DURING THE DAY DIP INTO THE MID TO UPPER TEENS BELOW ZERO FOR AWHILE IN THE NORTHWESTERN CWA...BUT DON/T QUITE REACH ADVISORY CRITERIA. THAT WILL CHANGE BY FRI NIGHT AS WINDS AND STOUT CAA MAINTAIN. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED LATER FRI NIGHT AND INTO SAT FOR MUCH OF THE DVN CWA. AS FOR ANOTHER CLIPPER SKIRTING DOWN ACRS THE AREA FRI NIGHT...THE GFS IS AGAIN THE MOST BULLISH WITH LIFT AND SATURATION AND LOOKS OVERDONE...BUT WILL KEEP CHC POPS FOR LIGHT SNOW AFTER MIDNIGHT AND INTO EARLY SAT MORNING. OTHERWISE OCCASIONAL FLURRIES WILL ACCOMPANY AND CLOUD COVER THAT SWEEPS ON THRU IN STEEP NORTHWEST FLOW WITH ANY SATURATION EASILY IN THE -10 C OR COLDER RANGE. 3RD NIGHT IN A ROW WHERE LATEST RUN AND ACCEPTED/FAVORED MEDIUM RANGE MODEL RUNS ADVERTISE MERIDIONAL FETCH FROM NORTHWEST OF THE HUDSON BAY REGION- ARCTIC BRINGING NEAR -30 C H85 COLD POOL DOWN NEAR THE FCST AREA SAT NIGHT INTO SUN. WILL CONTINUE TO MAKE MINOR TWEAKS/DOWN TRENDS IN BOTH HIGHS AND LOWS OVER THE WEEKEND...WITH THE CONTINUING THOUGHT OF AT LEAST SOME -20 F VALUES BEING REACHED IN PORTIONS OF THE FCST AREA EITHER SUNDAY MORNING OR MONDAY LOOKING ON TARGET. ONLY WEAKENING SFC WINDS WITH SOME LLVL RIDGING MAKING ITS WAY ACRS THE AREA LATER SAT NIGHT INTO SUNDAY MAY PRECLUDE A WIND CHILL WARNING FOR THAT TIME PERIOD...BUT STILL NOT OUT OF THE QUESTION. NO CHANGES INTO EARLY NEXT WEEK FOR NOW. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ DLF/12 ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 1026 AM CST THU FEB 1 2007 .UPDATE... FORECAST UPDATED FOR THIS AFTERNOON TO ACCOUNT FOR RADAR TRENDS AND LATEST 12Z RUC AND NAM RUNS. LIGHT SNOW CONTINUES TO DIMINISH THIS MORNING...WITH NO RADAR OR SURFACE INDICATIONS OF PRECIP WEST OF A PAH TO MVN LINE AT 16Z. OCNL LIGHT SNOW WILL END OVER REMAINDER OF FORECAST AREA IN NEXT FEW HOURS...FOLLOWED BY NOTHING MORE THAN SCTD FLURRIES. NEW 12Z RUC/NAM RUNS AND LATEST RADAR AND SFC REPORTS INDICATE ANY MEASURABLE SNOW WITH THE NEXT SYSTEM WILL NOT ARRIVE BEFORE 00Z...EXCEPT POSSIBLY OVER SE MISSOURI. CHANCE POPS FOR LATE AFTERNOON WILL COVER THESE AREAS. TEMPS ARE RUNNING 2 TO 3 DEGREES HIGHER THAN FORECAST. RAISED HIGHS 2 OR 3 DEGREES MOST AREAS. && .PREV DISCUSSION... GOING FORECAST IN GOOD SHAPE. AT 08Z...INITIAL BATCH OF LIGHT SNOW WAS MOSTLY EAST OF THE MISSISSIPPI RIVER. AMOUNTS HAVE GENERALLY BEEN A DUSTING TO 1/2 INCH...WITH SPOTTY 1 INCH AMOUNTS REPORTED. RADAR AND SATELLITE TRENDS CONFIRM THERE SHOULD BE A LULL THIS MORNING IN THE LIGHT SNOW ACTIVITY. CANNOT RULE OUT SOME TRACE WINTRY PRECIP THIS MORNING. BY MID TO LATE AFTERNOON...THE SECOND ROUND OF LIGHT SNOW SHOULD DEVELOP INTO SOUTHEAST MISSOURI AND EVENTUALLY FAR WEST KENTUCKY. THIS AREA SHOULD TRANSLATE ENE ACROSS THE REGION DURING THE EVENING...WITH HIGHEST POPS ACROSS THE SOUTHERN 1/2 OF THE FA. THE SREF CONGLOMERATE AND NAM ARE A TAD MORE AGGRESSIVE THAN THE GFS LATE TODAY. WILL TREND TOWARD THE SLIGHTLY QUICKER SOLUTIONS SEEN IN THE SREF / NAM OUTPUT. MODELS REMAIN FAIRLY CONSISTENT IN ADVERTISING UPWARDS OF 1 INCH OF SNOW WITH THE SECOND BATCH LATE TODAY AND TONIGHT ACROSS SOUTHERN SECTIONS OF THE FA. THERE MAY BE ISOLATED HIGHER AMOUNTS OF PERHAPS 1 1/2 INCHES OR SO. PRECIP TYPE IS STILL A QUESTION MARK ACROSS THE HOPKINSVILLE AREA...EAST OF THE LAND BETWEEN THE LAKES. THE NAM AND GFS BOUNDARY LAYER TEMPS ARE COOLER FOR 00Z TONIGHT THAN WHAT WAS SHOWN 24 HOURS AGO. 925/850MB UA CHARTS SHOW IT IS STILL VERY COLD OFF THE DECK. SO WE ARE THINKING MAINLY SNOW. HOWEVER WE WILL MAINTAIN A SMALL RAIN CHANCE WITH THE SNOW IN THE AFOREMENTIONED AREA LATE TODAY JUST IN CASE. FURTHER NORTH INTO SOUTHERN ILLINOIS AND SOUTHWEST INDIANA...THE CHANCE OF SNOW EXISTS...BUT THE PROBABILITY IS LOWER. THUS OUR ACCUMULATION FORECAST FOR THIS AREA WILL BE LOWER AS WELL. AT THIS TIME DO NOT PLAN ON AN ADVISORY. WILL CONTINUE TO HANDLE THIS EVENT WITH THE SPECIAL WEATHER STATEMENT PRODUCT. WE DO EXPECT THE SNOW CHANCE TO DIMINISH FROM WEST TO EAST OVERNIGHT. SO WE KEPT WITH OUR GOING CHANCE OF SOME LINGERING VERY LIGHT SNOW OR FREEZING DRIZZLE. NO CHANGES WERE MADE BEYOND TONIGHT. STILL A SLIGHT CHANCE OF SNOW FOR FRIDAY. THE NEXT SYSTEM IS FORECAST TO AFFECT THE AREA SUNDAY INTO SUNDAY NIGHT. THERE IS A CHANCE OF LIGHT SNOW WITH THIS SYSTEM. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGHOUT THE SEVEN DAY PERIOD. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ UPDATE...MY PREVIOUS...CN ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1210 AM EST THU FEB 01 2007 .AVIATION DISCUSSION (06Z) TAFS... CEILINGS WILL LOWER TO MVFR CONDITIONS BY 10Z ACROSS ALL OF THE TAF SITES AS AN AREA OF LIGHT SNOW ARRIVES. LIGHT SNOW...WITH VISIBILITIES GENERALLY REMAINING AROUND 2SM OR ABOVE WILL BEGIN AT BWG AFTER 6Z...SDF FROM 08-10Z AND AT LEX AND BWG AROUND 09-11Z. CEILINGS IN THE SNOW WILL FALL TO 2-3 THOUSAND FEET. SURFACE WINDS WILL REMAIN LIGHT OVERNIGHT WITH 20 KT SW FLOW AT AROUND 2000 FEET. LIGHT SNOW WILL CHANGE TO FLURRIES BY MID MORNING WITH ACCUMULATIONS REMAINING AT OR BELOW 1 INCH...BUT CEILINGS WILL REMAIN MVFR THROUGHOUT TODAY. ANOTHER ROUND OF LIGHT SNOW IS EXPECTED AFTER 00Z FRIDAY. JSD && .EVENING UPDATE (WEDS EVENING 9 PM) LATEST IR SATELLITE LOOP IS SHOWING SOME ENHANCEMENT IN THE CLOUD ELEMENTS OVER CENTRAL AND NORTHERN AR AND NRN AL ...LOOKING AT THE RADAR TRENDS THAT AREA...THEY ARE SHOWING SOME INCREASE IN COVERAGE TOO. BOTH THE CLOUDS AND PCPN ARE MOVING TO THE NORTHEAST TOWARDS SRN KY. A PRELIMINARY LOOK AT THE NEW 00Z NAM MODEL DATA IS NOT AS PROMISING FOR SNOWFALL. THE AIR ALOFT WAS INITIALLY QUITE DRY TODAY AND IF THE AIR DOESN`T BECOME SUFFICIENTLY SATURATED IN THE LOWER LEVELS... ANY PRECIP THAT DOES FALL WILL EVAPORATE BEFORE REACHING THE GROUND. THE 18Z GFS DID SHOW SUFFICIENT SATURATION AND ENOUGH SYNOPTIC LIFT FOR AN INCH OR TWO OF SNOWFALL ESPECIALLY DURING THE 10Z-18Z TIME FRAME ACROSS PORTIONS OF SOUTHERN KENTUCKY. THIS MATCHES WELL WITH OUR SNOW ADVISORY ACROSS THE SOUTHERN PORTION OF THE FA. THE LATEST RUC40 RH TRENDS SHOW A MAJOR INCREASE IN LOW LEVEL RH SW TO NE ACROSS MOST OF THE REGION OVERNIGHT...THIS TOO WUD SUPPORT THE POTENTIAL FOR MEASURABLE SNOW LATER TONIGHT. BEFORE MAKING ANY MAJOR CHANGES...WE NEED TO LOOK AT THE FULL SUITE OF 00Z MODEL RUNS...PLUS CHECK WITH THE NEXT HPC SNOW FCSTS AND CONSIDER THEIR ANALYSIS TOO. COORDINATED WITH JKL AND THEY WERE PLANNING TO LEAVE THEIR ADVISORY INTACT. AT THIS TIME WE ARE NOT MAKING ANY CHANGES IN THE CURRENT FCST. --21 ....PREVIOUS FCST DISCUSSIONS FOR TODAY ARE BELOW:... .SHORT TERM... (TONIGHT THROUGH THURSDAY NIGHT)... ...SNOW ADVISORY ACROSS SOUTHERN KY AND SOUTHERN BLUEGRASS... SHORT-TERM FORECAST REVOLVES AROUND SOUTHERN STREAM SYSTEMS AND SNOW ACCUMULATION CHANCES WITH EACH. TONIGHT-MIDDAY THURS... HIGH PRESSURE OVERHEAD WILL MOVE OFF TO THE EAST TONIGHT...AS AN INVERTED TROUGH OVER THE GULF MOVES FROM TEXAS TOWARD THE CAROLINAS. MOISTURE IS NOT TOO IMPRESSIVE WITH THIS SYSTEM...HOWEVER THE DYNAMICS ARE STRONG. SOUTHERN JET OF ROUGHLY 150 KTS OR SO WILL BE OVERHEAD...WITH THE CWA UNDER THE LEFT-EXIT REGION AFTER MIDNIGHT. AMPLE LIFT WILL THUS HELP SNOW DEVELOP AFTER MIDNIGHT TOWARD MORNING. AREA SOUNDINGS INDICATE THE BEST CHANCE OF SNOW WILL BE BETWEEN 10-17Z. SOME HEAVIER SNOW MAY MIX IN AT TIMES GIVEN UPSTREAM REPORTS AND PROGGED -EPV ALOFT CO-LOCATED WITH MAX OMEGAS. BUT GIVEN THE LACK OF MOISTURE AND SPEED OF SYSTEM...WILL NOT GET CARRIED AWAY WITH SNOW AMOUNTS. THUS...WILL ISSUE A SNOW ADVSY FROM 1-2 INCHES POSSIBLE MAINLY SE OF A LINE FROM MORGANTOWN TO LEBANON. MAY BE A BIT TOO FAR NORTH WITH THE ADVY GIVEN THE NAM 18Z RUN...BUT 12Z GFS/NAM AND HPC INDICATE FAR SRN KY COULD GET THESE ACCUMULATING SNOWS. THE BIGGER PROBLEM WILL BE TIMING NOT THE ACTUAL ACCUMS. GIVEN TIME OF DAY (NEAR MORNING COMMUTE TIME) FELT IT WAS WORTH BUMPING UP THE SPS TO AN ADVSY. WILL KEEP THE HIGHER SNOW AMOUNTS ACROSS THE FAR SERN CWA. ELSEWHERE...WILL CONTINUE SPS FOR AROUND AN INCH OF ACCUMULATION. FEEL THAT THE THREAT IS MINIMIZED ACROSS CENTRAL KY...HOWEVER A BETTER CHANCE MAY EXIST NEAR THE OHIO RIVER WITH THE DEFORMATION ZONE DEVELOPING FROM KC TO WICHITA. THIS SHOULD ALIGN SOMEWHERE ACROSS OUR NRN CWA...POSSIBLY NEAR THE KY/IN BORDER. SNOWFALL AMOUNTS WITHIN THE SPS AREA WILL BE HIGHER IN THE DEFORMATION ZONE...BUT IT IS STILL EXPECTED TO BE LIGHT SNOW ONLY. MAIN PRECIP WILL END BY MIDDAY (ADVY ENDS AT 18Z)...THOUGH LOW CLOUDS MAY CONTINUE THROUGH THE AFTERNOON. WITH THIS...EVEN A FEW LIGHT SHOWERS/FLURRIES MAY CONTINUE INTO THE AFTERNOON HOURS. SFC TEMPS MAY INCREASE ENOUGH ACROSS THE SOUTH WHERE A CHANGEOVER TO LIGHT RAIN/DRIZZLE MAY OCCUR. HAVE A RAIN/SNOW MIX ACROSS THE SOUTH FOR NOW. MIDDAY THURS-OVERNIGHT THURS... SECOND WAVE IN SOUTHERN STREAM WILL QUICKLY MOVE TOWARD THE EAST COAST RIGHT ON THE HEELS OF THE FIRST SYSTEM. THIS SYSTEM IS MORE OF A CLOSED SFC LOW AS OPPOSED TO A SFC TROUGH...AND IS COMBINED WITH EVEN STRONGER DYNAMICS ALOFT. HOWEVER MOISTURE IS EVEN MORE LACKING...BUT THE DYNAMICS ARE THERE FOR YET ANOTHER POSSIBLE ADVSY SITUATION THRS NIGHT-FRI MORN. WILL LOOK MORE AT IT TONIGHT AND TOMORROW MORNING...BUT WILL HIT IT HARD IN THE HWO. THIS LATTER SYSTEM WOULD BE MORE OF A CWA-WIDE EVENT TOO. WILL CONTINUE WITH ONE-INCH ACCUMS FOR NOW. AS FAR AS TEMPS GO THROUGH THE PERIOD...WILL ONLY DROP ABOUT 5 DEGREES TONIGHT BEFORE CLOUDS INCREASE OVERNIGHT AND KEEP OUR TEMPS STEADY. TOMORROW...WILL LIKELY HEAT UP...ESPECIALLY IN THE AFTERNOON. HOWEVER WILL UNDERCUT RUC13/GFS AS I FEEL THESE ARE RUNNING A BIT TOO HIGH. LOW TO MID 30S LOOK LIKELY FOR HIGHS THURS. AL .LONG TERM (FRI THRU WED)... FRI THRU SAT NGT... SHRTWV TROF WILL BE DROPPING DOWN INTO THE UPR MS VLY/WRN GREAT LAKES AT THE START OF THE PERIOD WITH MORE ENERGY ROUNDING THE BASE OF THE UPR LEVEL BROAD TROF TOWARD THE LOWER MS VLY. THIS ELONGATED AXIS OF HIER VORTICITY BECOMES INCREASINGLY SHEARED AS IT MOVES THRU OUR FA FRI WITH AFOREMENTIONED SHRTWV MOVG WELL TO OUR NORTH...ACRS THE GREAT LAKES. AFTERWARD...WE REMAIN IN A BROAD TROF THRU THE END OF THE PERIOD WITH ANOTHER IMPLSE APPROACHING OUR FA SAT NIGHT. ASSOCIATED CDFNT WILL MOVE THRU FRI...WITH A RIDGE OF HI PRES IN ITS WAKE FOR FRI NIGHT AND MUCH OF SAT. WILL CONTINUE CHC POPS FOR LIGHT SNOW PRECEDING FRONT...MAINLY IN THE FIRST HALF OF THE DAY. A REINFORCING SHOT OF COLD AIR...ASSOCIATED WITH AFOREMENTIONED IMPULSE...WILL LIKELY MOVE THRU OUR FA SAT NIGHT. WILL DOWNPLAY THE NAM/WRF DEEPER MOISTURE PRECEDING AND WITH FRONT AND CONT A PARTLY CLOUDY FCST...CLOSER TO THE GFS. 11 SUN THRU WED... VERY COLD AND MAINLY DRY THRU THIS PERIOD. BROAD UPR LEVEL TROF WILL RESIDE ACRS THE OH VLY THRU LATE MON WITH AXIS SHIFTING INTO NEW ENGLAND TUE AND OFF THE NEW ENGLAND COAST WED. AFTER AXIS PASSAGE MON...OUR REGION WILL BE IN COLD NW FLO THRU THE END OF THE PERIOD. 00Z MEDIUM RANGE MODELS AND 12Z GFS ARE SIMILAR WITH SHOWING A FAST MOVG CLIPPER SYS/WEAK SFC LO MOVING INTO THE LOWER OH VLY SUN NGT AND EXITING MON MORNING. THIS APPEARS TO BE OUR BEST CHC FOR A MEASURABLE SNOW DURING THIS PERIOD WITH POSSIBLY A 1 TO 3 INCH DRY FLUFFY SNOW ACRS OUR FORECAST AREA(FA)...MOSTLY OVER OUR NRN/ERN FA. TEMPS WILL BE UNSEASONALLY COLD...ESPECIALLY AFTER CLIPPER PASSAGE MON WITH SINGLE DIGIT READINGS MON AND TUE NGT AS ARCTIC HI PRES BUILDS INTO AND OVER THE LOWER OH VLY. AFTER POPULATING WITH HPC GRIDS FOR TUE AND WED...WILL MAKE THE FOLLOWING CHGS TO TEMP GRIDS. WILL RAISE SUN NGT MINS CONSIDERABLY TO ACCOUNT FOR INCREASING CLOUDS/A BRIEF PERIOD OF WARM ADVECTION AHEAD OF CLIPPER. WILL RAISE MAXS MON A FEW DEGREES CLOSER TO ENSEMBLE MEANS AND HPC AND TO AGREE BETTER WITH OUR NEIGHBORS. IF WE GET AN INCH OR TWO OF SNOW COVER BEFORE THIS PERIOD AND ON SUN NGT AS WELL...THESE TEMPS WILL NEED TO BE ADJUSTED DOWN...IN OTHER WORDS...BELOW ZERO FOR MINS BEGINNING MON NGT. DK && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 5 AM EST /4 AM CST/ TO 1 PM EST /12 PM CST/ THURSDAY FOR KYZ062>066-070>078-081-082. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 945 PM EST WED JAN 31 2007 .EVENING UPDATE DISCUSSION: LATEST IR SATELLITE LOOP IS SHOWING SOME ENHANCEMENT IN THE CLOUD ELEMENTS OVER CENTRAL AND NORTHERN AR AND NRN AL ...LOOKING AT THE RADAR TRENDS THAT AREA...THEY ARE SHOWING SOME INCREASE IN COVERAGE TOO. BOTH THE CLOUDS AND PCPN ARE MOVING TO THE NORTHEAST TOWARDS SRN KY. A PRELIMINARY LOOK AT THE NEW 00Z NAM MODEL DATA IS NOT AS PROMISING FOR SNOWFALL. THE AIR ALOFT WAS INITIALLY QUITE DRY TODAY AND IF THE AIR DOESN`T BECOME SUFFICIENTLY SATURATED IN THE LOWER LEVELS... ANY PRECIP THAT DOES FALL WILL EVAPORATE BEFORE REACHING THE GROUND. THE 18Z GFS DID SHOW SUFFICIENT SATURATION AND ENOUGH SYNOPTIC LIFT FOR AN INCH OR TWO OF SNOWFALL ESPECIALLY DURING THE 10Z-18Z TIME FRAME ACROSS PORTIONS OF SOUTHERN KENTUCKY. THIS MATCHES WELL WITH OUR SNOW ADVISORY ACROSS THE SOUTHERN PORTION OF THE FA. THE LATEST RUC40 RH TRENDS SHOW A MAJOR INCREASE IN LOW LEVEL RH SW TO NE ACROSS MOST OF THE REGION OVERNIGHT...THIS TOO WUD SUPPORT THE POTENTIAL FOR MEASURABLE SNOW LATER TONIGHT. BEFORE MAKING ANY MAJOR CHANGES...WE NEED TO LOOK AT THE FULL SUITE OF 00Z MODEL RUNS...PLUS CHECK WITH THE NEXT HPC SNOW FCSTS AND CONSIDER THEIR ANALYSIS TOO. COORDINATED WITH JKL AND THEY WERE PLANNING TO LEAVE THEIR ADVISORY INTACT. AT THIS TIME WE ARE NOT MAKING ANY CHANGES IN THE CURRENT FCST. --21 ....PREVIOUS FCST DISCUSSIONS FOR TODAY ARE BELOW:... .AVIATION DISCUSSION (00Z) FCSTS... GENERAL AC CIGS 10 THSD OR ABOVE TO START OUT TAFS...WITH GRADUAL INCREASE IN LOW AND MID LEVEL RH DURING THE NIGHT WHICH WILL EVENTUALLY LEAD TO SOME LIGHT SNOW...RIGHT NOW IT LOOKS AS THOUGH THE MAIN BAND OF LIGHT SNOW WILL BE ACROSS SRN KY...SO WILL EVENTUALLY LOWER CIG AND VSBY CONDITIONS TO IFR FOR BWG AND MVFR FOR LEX AND SDF. STILL SOME DOUBT ABOUT HOW MUCH SNOW WE WILL GET. WE WILL HAVE TO CONTINUE TO MONITOR WX AND MODEL TRENDS CLOSELY. --21 .SHORT TERM... (TONIGHT THROUGH THURSDAY NIGHT)... ...SNOW ADVISORY ACROSS SOUTHERN KY AND SOUTHERN BLUEGRASS... SHORT-TERM FORECAST REVOLVES AROUND SOUTHERN STREAM SYSTEMS AND SNOW ACCUMULATION CHANCES WITH EACH. TONIGHT-MIDDAY THURS... HIGH PRESSURE OVERHEAD WILL MOVE OFF TO THE EAST TONIGHT...AS AN INVERTED TROUGH OVER THE GULF MOVES FROM TEXAS TOWARD THE CAROLINAS. MOISTURE IS NOT TOO IMPRESSIVE WITH THIS SYSTEM...HOWEVER THE DYNAMICS ARE STRONG. SOUTHERN JET OF ROUGHLY 150 KTS OR SO WILL BE OVERHEAD...WITH THE CWA UNDER THE LEFT-EXIT REGION AFTER MIDNIGHT. AMPLE LIFT WILL THUS HELP SNOW DEVELOP AFTER MIDNIGHT TOWARD MORNING. AREA SOUNDINGS INDICATE THE BEST CHANCE OF SNOW WILL BE BETWEEN 10-17Z. SOME HEAVIER SNOW MAY MIX IN AT TIMES GIVEN UPSTREAM REPORTS AND PROGGED -EPV ALOFT CO-LOCATED WITH MAX OMEGAS. BUT GIVEN THE LACK OF MOISTURE AND SPEED OF SYSTEM...WILL NOT GET CARRIED AWAY WITH SNOW AMOUNTS. THUS...WILL ISSUE A SNOW ADVSY FROM 1-2 INCHES POSSIBLE MAINLY SE OF A LINE FROM MORGANTOWN TO LEBANON. MAY BE A BIT TOO FAR NORTH WITH THE ADVY GIVEN THE NAM 18Z RUN...BUT 12Z GFS/NAM AND HPC INDICATE FAR SRN KY COULD GET THESE ACCUMULATING SNOWS. THE BIGGER PROBLEM WILL BE TIMING NOT THE ACTUAL ACCUMS. GIVEN TIME OF DAY (NEAR MORNING COMMUTE TIME) FELT IT WAS WORTH BUMPING UP THE SPS TO AN ADVSY. WILL KEEP THE HIGHER SNOW AMOUNTS ACROSS THE FAR SERN CWA. ELSEWHERE...WILL CONTINUE SPS FOR AROUND AN INCH OF ACCUMULATION. FEEL THAT THE THREAT IS MINIMIZED ACROSS CENTRAL KY...HOWEVER A BETTER CHANCE MAY EXIST NEAR THE OHIO RIVER WITH THE DEFORMATION ZONE DEVELOPING FROM KC TO WICHITA. THIS SHOULD ALIGN SOMEWHERE ACROSS OUR NRN CWA...POSSIBLY NEAR THE KY/IN BORDER. SNOWFALL AMOUNTS WITHIN THE SPS AREA WILL BE HIGHER IN THE DEFORMATION ZONE...BUT IT IS STILL EXPECTED TO BE LIGHT SNOW ONLY. MAIN PRECIP WILL END BY MIDDAY (ADVY ENDS AT 18Z)...THOUGH LOW CLOUDS MAY CONTINUE THROUGH THE AFTERNOON. WITH THIS...EVEN A FEW LIGHT SHOWERS/FLURRIES MAY CONTINUE INTO THE AFTERNOON HOURS. SFC TEMPS MAY INCREASE ENOUGH ACROSS THE SOUTH WHERE A CHANGEOVER TO LIGHT RAIN/DRIZZLE MAY OCCUR. HAVE A RAIN/SNOW MIX ACROSS THE SOUTH FOR NOW. MIDDAY THURS-OVERNIGHT THURS... SECOND WAVE IN SOUTHERN STREAM WILL QUICKLY MOVE TOWARD THE EAST COAST RIGHT ON THE HEELS OF THE FIRST SYSTEM. THIS SYSTEM IS MORE OF A CLOSED SFC LOW AS OPPOSED TO A SFC TROUGH...AND IS COMBINED WITH EVEN STRONGER DYNAMICS ALOFT. HOWEVER MOISTURE IS EVEN MORE LACKING...BUT THE DYNAMICS ARE THERE FOR YET ANOTHER POSSIBLE ADVSY SITUATION THRS NIGHT-FRI MORN. WILL LOOK MORE AT IT TONIGHT AND TOMORROW MORNING...BUT WILL HIT IT HARD IN THE HWO. THIS LATTER SYSTEM WOULD BE MORE OF A CWA-WIDE EVENT TOO. WILL CONTINUE WITH ONE-INCH ACCUMS FOR NOW. AS FAR AS TEMPS GO THROUGH THE PERIOD...WILL ONLY DROP ABOUT 5 DEGREES TONIGHT BEFORE CLOUDS INCREASE OVERNIGHT AND KEEP OUR TEMPS STEADY. TOMORROW...WILL LIKELY HEAT UP...ESPECIALLY IN THE AFTERNOON. HOWEVER WILL UNDERCUT RUC13/GFS AS I FEEL THESE ARE RUNNING A BIT TOO HIGH. LOW TO MID 30S LOOK LIKELY FOR HIGHS THURS. AL .LONG TERM (FRI THRU WED)... FRI THRU SAT NGT... SHRTWV TROF WILL BE DROPPING DOWN INTO THE UPR MS VLY/WRN GREAT LAKES AT THE START OF THE PERIOD WITH MORE ENERGY ROUNDING THE BASE OF THE UPR LEVEL BROAD TROF TOWARD THE LOWER MS VLY. THIS ELONGATED AXIS OF HIER VORTICITY BECOMES INCREASINGLY SHEARED AS IT MOVES THRU OUR FA FRI WITH AFOREMENTIONED SHRTWV MOVG WELL TO OUR NORTH...ACRS THE GREAT LAKES. AFTERWARD...WE REMAIN IN A BROAD TROF THRU THE END OF THE PERIOD WITH ANOTHER IMPLSE APPROACHING OUR FA SAT NIGHT. ASSOCIATED CDFNT WILL MOVE THRU FRI...WITH A RIDGE OF HI PRES IN ITS WAKE FOR FRI NIGHT AND MUCH OF SAT. WILL CONTINUE CHC POPS FOR LIGHT SNOW PRECEDING FRONT...MAINLY IN THE FIRST HALF OF THE DAY. A REINFORCING SHOT OF COLD AIR...ASSOCIATED WITH AFOREMENTIONED IMPULSE...WILL LIKELY MOVE THRU OUR FA SAT NIGHT. WILL DOWNPLAY THE NAM/WRF DEEPER MOISTURE PRECEDING AND WITH FRONT AND CONT A PARTLY CLOUDY FCST...CLOSER TO THE GFS. 11 SUN THRU WED... VERY COLD AND MAINLY DRY THRU THIS PERIOD. BROAD UPR LEVEL TROF WILL RESIDE ACRS THE OH VLY THRU LATE MON WITH AXIS SHIFTING INTO NEW ENGLAND TUE AND OFF THE NEW ENGLAND COAST WED. AFTER AXIS PASSAGE MON...OUR REGION WILL BE IN COLD NW FLO THRU THE END OF THE PERIOD. 00Z MEDIUM RANGE MODELS AND 12Z GFS ARE SIMILAR WITH SHOWING A FAST MOVG CLIPPER SYS/WEAK SFC LO MOVING INTO THE LOWER OH VLY SUN NGT AND EXITING MON MORNING. THIS APPEARS TO BE OUR BEST CHC FOR A MEASURABLE SNOW DURING THIS PERIOD WITH POSSIBLY A 1 TO 3 INCH DRY FLUFFY SNOW ACRS OUR FORECAST AREA(FA)...MOSTLY OVER OUR NRN/ERN FA. TEMPS WILL BE UNSEASONALLY COLD...ESPECIALLY AFTER CLIPPER PASSAGE MON WITH SINGLE DIGIT READINGS MON AND TUE NGT AS ARCTIC HI PRES BUILDS INTO AND OVER THE LOWER OH VLY. AFTER POPULATING WITH HPC GRIDS FOR TUE AND WED...WILL MAKE THE FOLLOWING CHGS TO TEMP GRIDS. WILL RAISE SUN NGT MINS CONSIDERABLY TO ACCOUNT FOR INCREASING CLOUDS/A BRIEF PERIOD OF WARM ADVECTION AHEAD OF CLIPPER. WILL RAISE MAXS MON A FEW DEGREES CLOSER TO ENSEMBLE MEANS AND HPC AND TO AGREE BETTER WITH OUR NEIGHBORS. IF WE GET AN INCH OR TWO OF SNOW COVER BEFORE THIS PERIOD AND ON SUN NGT AS WELL...THESE TEMPS WILL NEED TO BE ADJUSTED DOWN...IN OTHER WORDS...BELOW ZERO FOR MINS BEGINNING MON NGT. DK && .AVIATION (18Z TAFS)... VFR CONDITIONS WILL CONTINUE FOR THE SDF...LEX AND BWG TAF SITES THROUGH THE FIRST SIX HOURS OF THIS TAF FORECAST. HIGH PRESSURE OVERHEAD WILL KEEP MOSTLY SUNNY CONDITIONS WITH LIGHT VARIABLE TO SOUTH WINDS...5 TO 10 MPH. MID-LEVEL DECK WILL FILTER IN FROM THE WEST FROM 21-00Z THIS EVENING. CIGS SHOULD STAY VFR UNTIL 06Z FOR BWG...AND BY 10Z AND 12Z FOR SDF AND LEX RESPECTIVELY...WHERE LIGHT SNOW MAY REDUCE VISBYS DOWN TO ONE MILE OR SO AT TIMES. ONSET OF -SN WILL BE LIGHT DUE TO LOWER LEVELS NOT BEING FULLY SATURATED. MAY CARRY A TEMPO FOR HEAVIER SNOW FOR THE BWG TAF ROUGHLY FROM 10-14Z. ONCE SNOW BEGINS...MAY TREND TOWARD LOWER END MVFR CIGS AND IFR VISBYS WITH THE HEAVIER SNOW SOMETIME BETWEEN 12-18Z FOR ALL TAF SITES. AL && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 5 AM EST /4 AM CST/ TO 1 PM EST /12 PM CST/ THURSDAY FOR KYZ062>066-070>078-081-082. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 624 PM EST WED JAN 31 2007 .AVIATION DISCUSSION (00Z) FCSTS... GENERAL AC CIGS 10 THSD OR ABOVE TO START OUT TAFS...WITH GRADUAL INCREASE IN LOW AND MID LEVEL RH DURING THE NIGHT WHICH WILL EVENTUALLY LEAD TO SOME LIGHT SNOW...RIGHT NOW IT LOOKS AS THOUGH THE MAIN BAND OF LIGHT SNOW WILL BE ACROSS SRN KY...SO WILL EVENTUALLY LOWER CIG AND VSBY CONDITIONS TO IFR FOR BWG AND MVFR FOR LEX AND SDF. STILL SOME DOUBT ABOUT HOW MUCH SNOW WE WILL GET. WE WILL HAVE TO CONTINUE TO MONITOR WX AND MODEL TRENDS CLOSELY. --21 .SHORT TERM... (TONIGHT THROUGH THURSDAY NIGHT)... ...SNOW ADVISORY ACROSS SOUTHERN KY AND SOUTHERN BLUEGRASS... SHORT-TERM FORECAST REVOLVES AROUND SOUTHERN STREAM SYSTEMS AND SNOW ACCUMULATION CHANCES WITH EACH. TONIGHT-MIDDAY THURS... HIGH PRESSURE OVERHEAD WILL MOVE OFF TO THE EAST TONIGHT...AS AN INVERTED TROUGH OVER THE GULF MOVES FROM TEXAS TOWARD THE CAROLINAS. MOISTURE IS NOT TOO IMPRESSIVE WITH THIS SYSTEM...HOWEVER THE DYNAMICS ARE STRONG. SOUTHERN JET OF ROUGHLY 150 KTS OR SO WILL BE OVERHEAD...WITH THE CWA UNDER THE LEFT-EXIT REGION AFTER MIDNIGHT. AMPLE LIFT WILL THUS HELP SNOW DEVELOP AFTER MIDNIGHT TOWARD MORNING. AREA SOUNDINGS INDICATE THE BEST CHANCE OF SNOW WILL BE BETWEEN 10-17Z. SOME HEAVIER SNOW MAY MIX IN AT TIMES GIVEN UPSTREAM REPORTS AND PROGGED -EPV ALOFT CO-LOCATED WITH MAX OMEGAS. BUT GIVEN THE LACK OF MOISTURE AND SPEED OF SYSTEM...WILL NOT GET CARRIED AWAY WITH SNOW AMOUNTS. THUS...WILL ISSUE A SNOW ADVSY FROM 1-2 INCHES POSSIBLE MAINLY SE OF A LINE FROM MORGANTOWN TO LEBANON. MAY BE A BIT TOO FAR NORTH WITH THE ADVY GIVEN THE NAM 18Z RUN...BUT 12Z GFS/NAM AND HPC INDICATE FAR SRN KY COULD GET THESE ACCUMULATING SNOWS. THE BIGGER PROBLEM WILL BE TIMING NOT THE ACTUAL ACCUMS. GIVEN TIME OF DAY (NEAR MORNING COMMUTE TIME) FELT IT WAS WORTH BUMPING UP THE SPS TO AN ADVSY. WILL KEEP THE HIGHER SNOW AMOUNTS ACROSS THE FAR SERN CWA. ELSEWHERE...WILL CONTINUE SPS FOR AROUND AN INCH OF ACCUMULATION. FEEL THAT THE THREAT IS MINIMIZED ACROSS CENTRAL KY...HOWEVER A BETTER CHANCE MAY EXIST NEAR THE OHIO RIVER WITH THE DEFORMATION ZONE DEVELOPING FROM KC TO WICHITA. THIS SHOULD ALIGN SOMEWHERE ACROSS OUR NRN CWA...POSSIBLY NEAR THE KY/IN BORDER. SNOWFALL AMOUNTS WITHIN THE SPS AREA WILL BE HIGHER IN THE DEFORMATION ZONE...BUT IT IS STILL EXPECTED TO BE LIGHT SNOW ONLY. MAIN PRECIP WILL END BY MIDDAY (ADVY ENDS AT 18Z)...THOUGH LOW CLOUDS MAY CONTINUE THROUGH THE AFTERNOON. WITH THIS...EVEN A FEW LIGHT SHOWERS/FLURRIES MAY CONTINUE INTO THE AFTERNOON HOURS. SFC TEMPS MAY INCREASE ENOUGH ACROSS THE SOUTH WHERE A CHANGEOVER TO LIGHT RAIN/DRIZZLE MAY OCCUR. HAVE A RAIN/SNOW MIX ACROSS THE SOUTH FOR NOW. MIDDAY THURS-OVERNIGHT THURS... SECOND WAVE IN SOUTHERN STREAM WILL QUICKLY MOVE TOWARD THE EAST COAST RIGHT ON THE HEELS OF THE FIRST SYSTEM. THIS SYSTEM IS MORE OF A CLOSED SFC LOW AS OPPOSED TO A SFC TROUGH...AND IS COMBINED WITH EVEN STRONGER DYNAMICS ALOFT. HOWEVER MOISTURE IS EVEN MORE LACKING...BUT THE DYNAMICS ARE THERE FOR YET ANOTHER POSSIBLE ADVSY SITUATION THRS NIGHT-FRI MORN. WILL LOOK MORE AT IT TONIGHT AND TOMORROW MORNING...BUT WILL HIT IT HARD IN THE HWO. THIS LATTER SYSTEM WOULD BE MORE OF A CWA-WIDE EVENT TOO. WILL CONTINUE WITH ONE-INCH ACCUMS FOR NOW. AS FAR AS TEMPS GO THROUGH THE PERIOD...WILL ONLY DROP ABOUT 5 DEGREES TONIGHT BEFORE CLOUDS INCREASE OVERNIGHT AND KEEP OUR TEMPS STEADY. TOMORROW...WILL LIKELY HEAT UP...ESPECIALLY IN THE AFTERNOON. HOWEVER WILL UNDERCUT RUC13/GFS AS I FEEL THESE ARE RUNNING A BIT TOO HIGH. LOW TO MID 30S LOOK LIKELY FOR HIGHS THURS. AL .LONG TERM (FRI THRU WED)... FRI THRU SAT NGT... SHRTWV TROF WILL BE DROPPING DOWN INTO THE UPR MS VLY/WRN GREAT LAKES AT THE START OF THE PERIOD WITH MORE ENERGY ROUNDING THE BASE OF THE UPR LEVEL BROAD TROF TOWARD THE LOWER MS VLY. THIS ELONGATED AXIS OF HIER VORTICITY BECOMES INCREASINGLY SHEARED AS IT MOVES THRU OUR FA FRI WITH AFOREMENTIONED SHRTWV MOVG WELL TO OUR NORTH...ACRS THE GREAT LAKES. AFTERWARD...WE REMAIN IN A BROAD TROF THRU THE END OF THE PERIOD WITH ANOTHER IMPLSE APPROACHING OUR FA SAT NIGHT. ASSOCIATED CDFNT WILL MOVE THRU FRI...WITH A RIDGE OF HI PRES IN ITS WAKE FOR FRI NIGHT AND MUCH OF SAT. WILL CONTINUE CHC POPS FOR LIGHT SNOW PRECEDING FRONT...MAINLY IN THE FIRST HALF OF THE DAY. A REINFORCING SHOT OF COLD AIR...ASSOCIATED WITH AFOREMENTIONED IMPULSE...WILL LIKELY MOVE THRU OUR FA SAT NIGHT. WILL DOWNPLAY THE NAM/WRF DEEPER MOISTURE PRECEDING AND WITH FRONT AND CONT A PARTLY CLOUDY FCST...CLOSER TO THE GFS. 11 SUN THRU WED... VERY COLD AND MAINLY DRY THRU THIS PERIOD. BROAD UPR LEVEL TROF WILL RESIDE ACRS THE OH VLY THRU LATE MON WITH AXIS SHIFTING INTO NEW ENGLAND TUE AND OFF THE NEW ENGLAND COAST WED. AFTER AXIS PASSAGE MON...OUR REGION WILL BE IN COLD NW FLO THRU THE END OF THE PERIOD. 00Z MEDIUM RANGE MODELS AND 12Z GFS ARE SIMILAR WITH SHOWING A FAST MOVG CLIPPER SYS/WEAK SFC LO MOVING INTO THE LOWER OH VLY SUN NGT AND EXITING MON MORNING. THIS APPEARS TO BE OUR BEST CHC FOR A MEASURABLE SNOW DURING THIS PERIOD WITH POSSIBLY A 1 TO 3 INCH DRY FLUFFY SNOW ACRS OUR FORECAST AREA(FA)...MOSTLY OVER OUR NRN/ERN FA. TEMPS WILL BE UNSEASONALLY COLD...ESPECIALLY AFTER CLIPPER PASSAGE MON WITH SINGLE DIGIT READINGS MON AND TUE NGT AS ARCTIC HI PRES BUILDS INTO AND OVER THE LOWER OH VLY. AFTER POPULATING WITH HPC GRIDS FOR TUE AND WED...WILL MAKE THE FOLLOWING CHGS TO TEMP GRIDS. WILL RAISE SUN NGT MINS CONSIDERABLY TO ACCOUNT FOR INCREASING CLOUDS/A BRIEF PERIOD OF WARM ADVECTION AHEAD OF CLIPPER. WILL RAISE MAXS MON A FEW DEGREES CLOSER TO ENSEMBLE MEANS AND HPC AND TO AGREE BETTER WITH OUR NEIGHBORS. IF WE GET AN INCH OR TWO OF SNOW COVER BEFORE THIS PERIOD AND ON SUN NGT AS WELL...THESE TEMPS WILL NEED TO BE ADJUSTED DOWN...IN OTHER WORDS...BELOW ZERO FOR MINS BEGINNING MON NGT. DK && .AVIATION (18Z TAFS)... VFR CONDITIONS WILL CONTINUE FOR THE SDF...LEX AND BWG TAF SITES THROUGH THE FIRST SIX HOURS OF THIS TAF FORECAST. HIGH PRESSURE OVERHEAD WILL KEEP MOSTLY SUNNY CONDITIONS WITH LIGHT VARIABLE TO SOUTH WINDS...5 TO 10 MPH. MID-LEVEL DECK WILL FILTER IN FROM THE WEST FROM 21-00Z THIS EVENING. CIGS SHOULD STAY VFR UNTIL 06Z FOR BWG...AND BY 10Z AND 12Z FOR SDF AND LEX RESPECTIVELY...WHERE LIGHT SNOW MAY REDUCE VISBYS DOWN TO ONE MILE OR SO AT TIMES. ONSET OF -SN WILL BE LIGHT DUE TO LOWER LEVELS NOT BEING FULLY SATURATED. MAY CARRY A TEMPO FOR HEAVIER SNOW FOR THE BWG TAF ROUGHLY FROM 10-14Z. ONCE SNOW BEGINS...MAY TREND TOWARD LOWER END MVFR CIGS AND IFR VISBYS WITH THE HEAVIER SNOW SOMETIME BETWEEN 12-18Z FOR ALL TAF SITES. AL && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 5 AM EST /4 AM CST/ TO 1 PM EST /12 PM CST/ THURSDAY FOR KYZ062>066-070>078-081-082. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 252 PM CST WED JAN 31 2007 .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... BASED ON SURFACE REPORTS...THE LEADING EDGE OF THE SNOW IS A FEW HOURS AHEAD OF SCHEDULE. AT 20Z...SPOTTERS REPORTED SNOW ALREADY BEGINNING IN CARTER AND RIPLEY COUNTIES IN SE MISSOURI. AT 19Z...STEADY SNOW WAS FALLING AT JBR/UNO/VIH. THE 09Z SREF AND 18Z RUC ARE AMONG THE FASTEST OF THE MODELS AND APPEAR TO HAVE THE BEST HANDLE ON TIMING. EXPECT SNOW TO OVERSPREAD SE MISSOURI BY AROUND 00Z...REACHING EVV AND HOP AREAS BY 06Z. RADAR RETURNS AND SURFACE OBS INDICATE SOME POCKETS OF MODERATE TO HEAVY SNOW...WITH VSBY ON OCCASION ONE HALF MILE OR LESS AT JBR AND HRO. THE SNOW IS LIKELY TO VARY IN INTENSITY...AS SHOWN BY VISIBILITIES RANGING FROM 1/2 TO 7 MILES OVER NRN ARKANSAS. THIS AREA OF SNOW CORRELATES WELL WITH STRONG LOW LEVEL WARM ADVECTION PATTERN AND ASSOCIATED ISENTROPIC ASCENT ON 295K SURFACE. NAM/GFS DEPICT THIS AREA OF ASCENT SHIFTING EASTWARD ACROSS THE MID MISSISSIPPI VALLEY TONIGHT...EXITING THE LOWER OHIO VALLEY EARLY THURSDAY. HPC AND MODEL QPF GUIDANCE IS UNANIMOUS...INDICATING AROUND ONE TENTH INCH OR LESS TONIGHT. THIS TRANSLATES TO GENERALLY AN INCH OR LESS OF SNOW. SREF INDICATES CLOSE TO ONE TENTH LIQUID EQUIVALENT OVER FAR WESTERN COUNTIES...WHICH MAY YIELD A COUPLE OF INCHES OF DRY POWDERY SNOW IN SPOTS. AFTER THE DEPARTURE OF THE MAIN PRECIP AREA EARLY THURSDAY...A 500 MB SHORTWAVE WILL TRACK NORTHEAST FROM TEXAS. MODELS ARE NOT IN GOOD AGREEMENT REGARDING THE STRENGTH AND PATH OF THIS SYSTEM...ESPECIALLY CONSIDERING ITS ONLY 24 TO 36 HOURS OUT. THE MODEL CONSENSUS IS THAT THE SHORTWAVE WILL FLATTEN OUT AS IT APPROACHES THE LOWER MISSISSIPPI VALLEY IN THE VICINITY OF WEST TENNESSEE. THE 12Z OPERATIONAL NAM/GFS SPREAD QPF INTO SOUTHERN PARTS OF MISSOURI AND WEST KENTUCKY LATE IN THE DAY WITH THIS FEATURE. PROLONGED SOUTHERLY LOW LEVEL FLOW TONIGHT AND THURSDAY WILL EVENTUALLY WARM THE BOUNDARY LAYER ENOUGH THAT PRECIP TYPE IS AN ISSUE BY THURSDAY EVENING. SURFACE AND BOUNDARY LAYER TEMPS SHOULD CLIMB SLIGHTLY ABOVE FREEZING THURSDAY SOUTH OF THE OHIO RIVER. WHILE SNOW SHOULD BE THE PREDOMINANT PRECIP TYPE DUE TO LOW FREEZING LEVELS...COULD NOT RULE OUT SOME RAIN IN FAR SOUTHERN COUNTIES. GIVEN THE RAPID SPEED OF THE SYSTEM...12Z MODEL QPF OF UP TO ONE TENTH INCH OVER 6 HOURS LOOKS REASONABLE. THIS WOULD YIELD ANOTHER INCH OR SO. A QUICK PEEK AT THE ARRIVING 15Z SREF GUIDANCE IS CONSIDERABLY FURTHER NORTH AND A LITTLE HEAVIER WITH QPF WITH THIS SYSTEM...VERSUS THE FURTHER SOUTH APPEARANCE OF THE 12Z OPERATIONAL RUNS AND 09Z SREF RUNS. WILL MAINTAIN POPS AS IS. AFTER THE DEPARTURE OF THE THURSDAY EVENING SHORTWAVE...THE LOW LEVEL FLOW WILL GRADUALLY TURN NORTHWEST AND BRING SOME COLDER AIR IN. MODELS CONTINUE TO INDICATE PLENTY OF LOW AND MID LEVEL MOISTURE LINGERING THROUGH FRIDAY. A 500 MB SHORTWAVE OVER THE FOUR CORNERS REGION AT 12Z FRIDAY WILL RACE EAST ACROSS THE SOUTHERN PLAINS DURING THE DAY. THIS RESULTS IN SOME LIGHT QPF OVER OUR REGION PER THE NAM MODEL...AND CHANCE POPS IN GFS/NAM MOS GUIDANCE. WILL INTRODUCE SLIGHT CHANCE POPS FOR FRIDAY...ALTHOUGH FLURRIES ARE ALREADY MENTIONED. SOME PARTIAL CLEARING IS EXPECTED FRIDAY NIGHT AS STRONG SURFACE HIGH BUILDS EAST ACROSS THE PLAINS. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... MAIN CONCERN IN THE LONG TERM IS ANOTHER ARCTIC FRONT SUNDAY AFTERNOON AND NIGHT. THE 06Z AND 12Z GFS AND 06Z MREF DATA SUPPORT A MENTION OF LIGHT SNOW WITH THE FRONT. THE FRONT WILL LEAD A LARGE 1040+ SURFACE HIGH INTO THE REGION...SO THE WELL BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH NEXT WEEK. THE GFS INDICATES ANOTHER STORM SYSTEM MOVING TOWARD THE REGION FOR WEDNESDAY INTO THURSDAY. FOR NOW DECIDED TO LEAVE IT DRY AND WAIT FOR SOME CONTINUITY BEFORE INTRODUCING PRECIPITATION TO THE FORECAST. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ MY/DRS ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 958 PM CST WED JAN 31 2007 .DISCUSSION... AREAS OF RAIN...POSSIBLY MIXED WITH A FEW IP/S...CONTINUES ACROSS NORTHCENTRAL/NE LA THIS EVENING...MAINLY IN ASSOCIATION OF STRONG ISENTROPIC ASCENT ALONG THE 295-305K SURFACES. HOWEVER...IP THREAT WILL BE SHORT LIVED HERE AS 00Z KSHV RAOB INDICATES THAT WEAK WARM ADVECTION HAS WARMED/MOISTENED THE AIR COLUMN ENOUGH BELOW 9KFT SUCH THAT EVAPORATIVE COOLING IS NO LONGER BECOMING AN ISSUE FOR IP FORMATION. FARTHER N...SN/IP HAS TAPERED THIS EVENING AS ISENTROPIC FORCING ALONG THE 295K SURFACE HAS SHIFTED E OF THE REGION. BELIEVE THE REST OF THE NIGHT WILL BE SOMEWHAT QUIET...UNTIL MAIN SHORTWAVE ENERGY APPROACHES THE REGION FROM THE W...IN ASSOCIATED WITH THE MERGING OF THE BAJA LOW WITH THE NEXT SHORTWAVE ROUNDING THE N STREME JET. NAM/RUC SOUNDINGS INDICATE A WARM NOSE DEVELOPING AROUND 3500FT ACROSS SW/SOUTHCENTRAL AR /TXK AND ELD/...SUCH THAT FROZEN HYRDROMETEORS WILL MELT ENOUGH FOR A RAIN/IP MIX. HOWEVER...EXPECTING TEMPS TO REMAIN JUST ABOVE FREEZING OVERNIGHT AT TXK...THUS HAVE CANCELLED THE WINTER ADV. FOR BOWIE AND MILLER COUNTIES. ALTHOUGH TEMPS WILL REMAIN NEAR FREEZING AT ELD. HOWEVER...HAVE ENOUGH CONFIDENCE IN KEEPING A WINTER WX ADVISORY OUT OF ELD FOR NOW...AS THE WINTRY MIX SHOULD AWAIT UNTIL AFTER 12Z THURSDAY. EVEN FORECATS SOUNDINGS HERE SUPPORT CONSIDERABLE WARM NOSING AFTER 6Z AND THEREAFTER...SUCH THAT ANY RAIN THAT FALLS THROUGH THE WARMER AIR WILL TEND TO SLIGHTLY WARM SURFACE TEMPS/DEWPOINTS. HOWEVER...WILL ADDRESS LEFTOVER WATER/ADDITIONAL LIGHT PRECIP. THAT OCCURS TONIGHT IN AN SPS FOR THIS AREA...AS WELL AS A COUPLE OF N LA PARISHES...AS RAWS REPORTS INDICATE THEM NEAR FREEZING AS WELL. ELSEWHERE...FORECAST SOUNDINGS SUPPORT A MIX OF SN/IP MIX LATE ACROSS RED RIVER...MCCURTAIN...SEVIER AND HOWARD COUNTIES WITH THE NEXT SHORTWAVE APPROACHING...BUT ADDITIONAL SNOW/ICE ACCUMULATIONS THROUGH 12Z WILL BE LIGHT. THUS...HAVE OPTED TO RETAIN THE WINTER ADV. FOR THESE AREAS...AS WELL AS HEMPSTEAD/NEVADA COUNTIES AS THESE AREAS WILL REMAIN NEAR/BELOW FREEZING. TOUGH CALL IN TERMS OF HOW LONG THESE AREAS WILL SUPPORT FROZEN PRECIP. THURSDAY...AS WARM ADVECTION REGIME CONTINUES...ALTHOUGH FAR NW COUNTIES MAY SEE MIXED WINTRY PRECIP. FOR MUCH OF THE DAY. WARM ADVECTION MAY CHANGEOVER PRECIP. TO RAIN BY MIDDAY/EARLY AFTERNOON OVER HEMPSTEAD/NEVADA COUNTIES...BUT WILL LET THE MID SHIFT ADDRESS THIS ISSUE. COULD STILL SEE 1-3" OF SNOW ACROSS N MCCURTAIN COUNTY AND POSSIBLY SEVIER/HOWARD COUNTIES BEFORE THE PRECIP. WANES LATE THURSDAY...WITH ICE ACCUMULATIONS OF ONE TENTH TO ONE QUARTER OF AN INCH ELSEWHERE IN THE ADVISORY AREA...BUT THIS WILL BE HIGHLY DEPENDENT ON AMOUNT OF WARMING /ABOVE FREEZING/ THROUGH THE DAY. IN ALL...ADJUSTED POPS TONIGHT DOWN EXCEPT WHERE PRECIP. LINGERS CURRENTLY. ALSO TOOK OUT FROZEN PRECIP. MENTION THURSDAY MORNING ACROSS E TX/N LA S OF I-20...AND MADE MINOR TWEAKS TO THE MIN TEMPS GRIDS TONIGHT...WITH LITTLE CHANGE/SLOW WARMING EXPECTED OVERNIGHT. OTHERWISE...REMAINDER OF THE FORECAST IS IN GOOD SHAPE. UPDATED FORECAST/WSW ALREADY OUT...SPS WILL BE ISSUED SHORTLY. 15 && .AVIATION... A LARGE AREA OF RAIN MIXED WITH ISOLATED AREAS OF LIGHT SLEET WILL COVER MUCH OF DEEP EAST TEXAS ACROSS LOWER PARTS OF NORTHWEST LOUISIANA INTO NORTH CENTRAL LOUISIANA AND SOUTHEAST ARKANSAS. LUCKILY TEMPERATURES WITHIN THIS LARGE AREA REMAIN AND SHOULD REMAIN BELOW FREEZING KEEPING THE PRECIPITATION LIQUID...WITH JUST A FEW SLEET PELLETS. LOW LEVEL WARM ADVECTION SHOULD ALLOW MOST OF THE MIXED PRECIPITATION TO BECOME MOSTLY RAIN OVER DEEP E TX AND ACROSS LA BY LATE TONIGHT. THIS RAIN AREA WILL ALSO DECREASE IN AREAL COVERAGE BY 01/12Z. MOST PRECIPITATION HAS ENDED OVER NORTHEAST TEXAS INTO SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA. CEILINGS THIS EVENING HAVE BEEN RANGING FROM AROUND 1 KFT TO 2.5 KFT FOR MUCH OF THE FOUR STATE REGION...WITH CEILINGS ACROSS DEEP EAST TEXAS ACROSS LOWER SECTIONS OF NORTHWEST AND INTO LOWER NORTH CENTRAL LOUISIANA RANGING FROM NEAR 4 HND TO 8 HND FEET. VISIBILITIES HAVE BEEN GTE 6 STATUE MILES EXCEPT IN THE HEAVIER RAIN AREAS WHERE THEY HAVE LOWERED TO 1 TO 3 STATUE MILES. AFTER 01/06Z TOWARD 01/12Z EXPECTING ANOTHER ROUND OF RAIN TO RETURN AS A SURFACE LOW PRESSURE SYSTEM SLIDES EAST ACROSS THE GULF OF MEXICO AND HIGH PRESSURE CENTERED ALONG THE COAST OF THE CAROLINAS SHIFTS EAST. ANOTHER LOW OVER W TX WILL ADVANCE EAST. ABUNDANT MOISTURE RIDING OVER THE FOUR STATE REGION WILL PRODUCE RAIN AND A WINTERY MIX ESPECIALLY OVER PARTS OF NE TX...SE OK...AND SW AR NEAR AND ALONG THE INTERSTATE 30 CORRIDOR WITH MOSTLY RAIN ALONG AND NEAR THE INTERSTATE 20 CORRIDOR. AFTER 01/12Z RAIN WILL BE INCREASING AND SPREADING AREA WIDE WITH CEILINGS FROM 4 TO 8 HND FEET. IN THE COLDER AREAS THERE WILL BE A MIX OF SNOW...SLEET...AND WITH EARLY START MIX OF FREEZING RAIN NEAR INTERSTATE 30. /06/ && .PRELIMINARY POINT TEMPS/POPS... SHV 35 41 35 45 / 40 90 20 10 MLU 34 40 36 48 / 80 90 20 10 DEQ 29 36 28 42 / 50 90 20 10 TXK 33 37 31 44 / 50 90 20 10 ELD 32 39 32 46 / 40 90 20 10 TYR 36 42 34 45 / 50 90 10 10 GGG 35 43 34 45 / 50 90 10 10 LFK 39 46 38 50 / 70 90 10 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...WINTER WEATHER ADVISORY UNTIL 4 PM THURSDAY FOR THE FOLLOWING ZONES: HEMPSTEAD...HOWARD...LITTLE RIVER...NEVADA...AND SEVIER. LA...NONE. OK...WINTER WEATHER ADVISORY UNTIL 4 PM THURSDAY FOR THE FOLLOWING ZONES: MCCURTAIN. TX...WINTER WEATHER ADVISORY UNTIL 4 PM THURSDAY FOR THE FOLLOWING ZONES: RED RIVER. && $$ 15/06 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 515 PM EST THU FEB 1 2007 ...SEVERAL DAYS OF VERY COLD AIR EXPECTED THIS WEEKEND INTO NEXT WEEK... .DISCUSSION... MAIN CONCERN FOR SHORT TERMS IS HEADLINES IN EFFECT ALONG NRN TIER OF CWFA. SHORTWAVE MOVING EWD FROM THE NRN PLAINS WILL SWEEP THROUGH THE AREA TONIGHT THROUGH EARLY FRIDAY. THE ARCTIC BOUNDARY ASSOCIATED WITH THIS SHORTWAVE HAS ALREADY MOVED THROUGH WRN UPR MI THIS AFTERNOON AND WILL CONTINUE TO SURGE SOUTH AND EAST TONIGHT THROUGH EARLY FRIDAY AS THE SHORTWAVE MOVES THROUGH. THE BOUNDARY WILL THEN DRIFT BACK TO THE NORTH LATE FRIDAY AFTERNOON INTO FRIDAY NIGHT...BEFORE IT IS GETS PUSHED SOUTHWARD AGAIN BY ANOTHER SHORTWAVE FRIDAY NIGHT AND SATURDAY. THIS SECOND SHORTWAVE IS CURRENTLY DIVING THROUGH SASKATCHEWAN AND MANITOBA ROTATING AROUND THE UPPER LOW OVER ERN CANADA. LOCATIONS THAT WILL BE IMPACTED BY SIGNIFICANT LAKE ENHANCED SNOW TONIGHT AND FRIDAY IS TOUGH TO PIN DOWN SINCE MUCH WILL DEPEND ON THE BOUNDARY LAYER WIND FLOW AND ASSOC LOW-LEVEL CONVERGENCE. ALL OTHER FACTORS ARE SUGGESTING THE POTENTIAL OF A GOOD LAKE ENHANCED EVENT...WITH DECENT Q-VECTOR CONVERGENCE...DEEP MOISTURE (APPARENT ON 12Z KINL SOUNDING) AND GOOD SNOW GROWTH POTENTIAL IN THE POSITIVE AREA OF THE CBL. THE WARNING PUT UP OVER THE KEWEENAW THIS AFTERNOON THROUGH SATURDAY LOOKS GOOD AS LOW-LEVEL CONVERGENCE WILL BE MAXIMIZED FOR A LONGER PERIOD THERE. WITH THE ARCTIC BOUNDARY DROPPING SOUTH THROUGH ONTONAGON AND INTO GOGEBIC COUNTY THIS EVENING...WARNING POSTED THERE AS WELL WITH HEAVY LES ACCUMS TONIGHT INTO MIDDAY FRI. AS THE BOUNDARY LIFT BACK TO THE NORTH ON FRIDAY LES WILL TAPER OFF OVER GOGEBIC AND ONTONAGON COUNTIES...BUT CONVERGENCE AXIS LINGERS OVER THE KEWEENAW UNTIL THE NEXT SHORTWAVE ARRIVES FRI NIGHT. THE FCST WILL BE TRICKIER FOR NCNTRL AND ERN COUNTIES AS BOUNDARY LAYER WIND DIRECTIONS ARE SOMEWHAT UNCERTAIN DUE TO POSITION OF LOW FCST TO DEVELOP OVER ERN LAKE SUPERIOR LATE TONIGHT. USED A BLEND OF THE NAM...RUC13...LOCAL 5KM WRF-ARW...AND REGIONAL GEM TO AID IN FCST WINDS FOR NORTH CENTRAL UPPER MICHIGAN LATE TONIGHT INTO FRI. THERE IS GENERAL AGREEMENT THAT THE FRONTAL BOUNDARY AND ASSOCIATED CONVERGENCE AXIS WILL MOVE INTO THE AREA LATE TONIGHT AND LINGER INTO FRIDAY AFTERNOON. HOWEVER...WITH THE MODELS SUGGESTING A CLOSED LOW DEVELOPING OVER SOUTHEAST LAKE SUPERIOR...THE BL WIND DIRECTIONS AND TIMING OF WIND SHIFT WILL BE HIGHLY DEPENDENT ON WHERE THE LOW WILL BE LOCATED. FOLLOWING A BLEND OF THE RUC13 AND 18Z NAM...BELIEVE A BURST OF HEAVIER SNOW WILL REACH INTO BARAGA AND MQT COUNTIES AFTER MIDNIGHT TONIGHT AND THEN INTO ALGER COUNTY FRI INTO FRI EVENING. GIVEN THE UNCERTAINTY WITH THE WINDS WILL KEEP GOING ADVISORIES UP FOR THESE COUNTIES. LUCE AND NRN SCHOOLCRAFT COUNTIES WILL LIKELY NEED A HEADLINE AS WELL FOR FRI INTO FRI EVENING. LATER SHIFTS WILL DEFINITELY NEED TO KEEP AN EYE ON THINGS...SINCE SUBTLE DIFFERENCES IN THE SURFACE LOW LOCATION AND WIND FIELD WILL HAVE A BIG IMPACT ON THE LOCATIONS IMPACTED AND PERHAPS ADVISORIES MAY BE NEED TO BE UPGRADED TO WARNINGS FOR A FEW COUNTIES. AS THE POLAR VORTEX HEADS S...THE SHORTWAVE DIVING THROUGH SASKATCHEWAN AND MANITOBA WILL MOVE THROUGH THE UPPER LAKES FRI NIGHT. DEEP Q-VECT CONV AND MOISTURE ASSOC WITH THIS SHORTWAVE WILL BRING ANOTHER ROUND OF HVY LAKE ENHANCED SNOW TO WRN UPR MI FRI NIGHT AS MODELS INDICATE ANOTHER SFC LOW DEVELOPING OVER ERN LAKE SUPERIOR. ENHANCED LOW-LEVEL CONVERGENCE FROM THIS DEVELOPING SFC LOW WILL HELP FOCUS LAKE ENHANCED SNOW INTO NW UPPER MI FRI NIGHT IN NWRLY FLOW. ALSO...MODELS INDICATE THAT AIRMASS INITIALLY WILL NOT BE TOO COLD TO INHIBIT SNOW GROWTH MICROPHYSICS...SO SNOW ACCUMULATIONS POTENTIALLY COULD BE HVY...ESPECIALLY CONSIDERING THE LOW-LEVEL CONVERGENCE. DEVELOPMENT OF ERN LAKE SUPERIOR LOW PRES AND STRENGTHENING LAND BREEZE SHOULD RESULT IN WINDS BACKING ENOUGH TO KEEP HEAVIEST LES OFFSHORE OF THE NE FCST AREA FRI NIGHT. AS SFC LOW PASSES E OF THE FCST AREA ON SAT...CONVERGENT N-NW THEN SHIFTS ONSHORE INTO ALGER AND LUCE COUNTIES. FOR THESE ERN COUNTIES....SNOW GROWTH INITIALLY MAY BE SOMEWHAT FAVORABLE ON SAT AND THERE COULD BE SOME ENHANCEMENT AS MODELS HINT AT A SHORTWAVE MOVING ACROSS ERN LAKE SUPERIOR. GIVEN ABOVE FACTORS/REASONING AND FACT THAT BITTER COLD AIRMASS WILL FOLLOW HEAVY LES INTO SUN...WILL NEED TO ISSUE A WINTER STORM WATCH FOR ONTONAGON AND SRN HOUGHTON COUNTIES LATE FRI NIGHT THROUGH SAT. WILL MAINTAIN WINTER STORM WARNING CURRENTLY IN EFFECT FOR NRN HOUGHTON AND KEWEENAW COUNTIES THROUGH SAT. WILL ALSO ISSUE A WINTER STORM WATCH FOR ALGER AND LUCE COUNTIES SAT THROUGH SUN. REST OF THE WEEKEND AND INTO EARLY NEXT WEEK...THE COLDEST AIR OF THE SEASON WILL SETTLE OVER THE REGION SAT NIGHT AND INTO MON. CONSENSUS OF MODELS INDICATES THAT 850MB TEMPS WILL LOWER INTO THE -28 TO -33C RANGE. THERE IS A VERY GOOD CHANCE THAT SOME LOCATIONS OVER THE W HALF OF UPPER MI (AWAY FROM LAKE SUPERIOR) MAY REMAIN BLO ZERO FROM FRI NIGHT THROUGH TUE MORNING. MIN TEMPS WILL LIKELY PLUMMET INTO THE -10F TO -20F RANGE AWAY FROM LAKE SUPERIOR/S MODERATING INFLUENCE. AS FOR LAKE EFFECT POTENTIAL...ALTHOUGH GFS FCST SOUNDINGS INDICATE FAIRLY MOIST CONDITIONS AND RELATIVELY HIGH INVERSIONS...POOR SNOWFLAKE GROWTH DUE TO VERY COLD AIRMASS WILL PROBABLY BE A BIG LIMITING FACTOR ON SNOW ACCUMULATIONS. IT REMAINS TO BE SEEN IF ENHANCED LOW-LEVEL CONVERGENCE FROM LAND BREEZES COULD YIELD HEAVIER LES OVER ONTONAGON-HOUGHTON AND ERN SHORELINE COUNTIES DESPITE COLD AIRMASS. EXPECTED SMALL SNOWFLAKES AND ANY ACCOMPANYING WIND COULD STILL BE VERY EFFECTIVE AT REDUCING VISIBILITY TO NEAR ZERO AT TIMES IN SNOW AND BLOWING SNOW. MODEL CONSENSUS SHOWS A SLIGHT MODERATION IN 850 MB TEMPS (AROUND -18C) BY WED/THU WHICH SHOULD HELP BRING DAYTIME TEMPS UP INTO TEENS. LOOK FOR NIGHTTIME LOWS TO STILL FALL BELOW ZERO...ESPECIALLY OVER THE INTERIOR WEST HALF. SNOW GROWTH FOR LES ALONG LAKE SUPERIOR COUNTIES MAY BE SLIGHTLY MORE FAVORABLE AS AIRMASS MODIFIES A BIT. && .MQT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING THROUGH 6PM EST SATURDAY MIZ001-003. WINTER STORM WARNING 10 PM EST THIS EVENING THROUGH 4 PM EST FRIDAY MIZ002. WINTER STORM WARNING 9 PM CST THIS EVENING THROUGH 9 AM CST FRIDAY MIZ009. WINTER STORM WARNING MIDNIGHT EST TONIGHT THROUGH 4 PM EST FRIDAY MIZ084. WINTER WEATHER ADVISORY MIDNIGHT EST TONIGHT THROUGH 4 PM EST FRIDAY MIZ004. WINTER WEATHER ADVISORY 1 AM EST TONIGHT THROUGH 4 PM EST FRIDAY MIZ005. WINTER WEATHER ADVISORY 7 AM EST THROUGH 10 PM EST FRIDAY MIZ006. WINTER STORM WATCH LATE FRIDAY NIGHT THROUGH SATURDAY MIZ002-004-084. WINTER STORM WATCH SATURDAY THROUGH SUNDAY MIZ006-007. HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1152 PM EST WED JAN 31 2007 .AVIATION... EXAMINATION OF AVAILABLE 00Z MODEL RUNS REVEALS GOOD CONTINUITY WITH THE DAYTIME/18Z RUNS. MID AND HIGH CLOUDS EXPECTED TO PREVAIL FOR MOST OF THE NIGHT...WITH THE MID CLOUDS CURRENTLY THICKENING/LOWERING WITH TIME IN AGREEMENT WITH MODEL SOUNDINGS AND MOISTURE TIME SECTIONS. BY 09Z AT KMBS AND EARLY FORENOON AT THE OTHER TAF SITES...EXPECT LOWERING CEILINGS INTO MVFR AS DEARTH OF LOW LEVEL MOISTURE ENDS...WITH THE NORTH AIDED BY TRAJECTORY OFF OF LAKE MICHIGAN. NEARLY ADIABATIC LOW LEVEL LAPSE RATES DEVELOPING THURSDAY AS COLD TEMPERATURES ALOFT PROMOTE EXPECTED DIURNAL BOOST FOR SNOW SHOWERS. TAFS WILL CONTINUE A PROB30 GROUP BETWEEN 17Z TO 21Z OR 18Z TO 22Z FOR MVFR VISIBILITIES IN SNOW SHOWERS. NOT ENOUGH CONFIDENCE IN POTENTIAL OVERNIGHT TO MENTION ANY VISIBILITY RESTRICTING SNOWFALL...AS LOW LEVEL MOISTURE WILL BE SPARSE. MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE LOTS OF LOW LEVEL MOISTURE/CLOUDS THURSDAY EVENING...THOUGH WITH LOSS OF DIURNAL INFLUENCES WILL NOT MENTION ANY VISIBILITY RESTRICTIONS. && .PREV DISCUSSION...ISSUED 434 PM EST WED JAN 31 2007 SHORT TERM...TONIGHT AND THURSDAY OVERNIGHT LOWS LIKELY TO OCCUR SHORTLY AFTER SUNSET...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE AREA WHERE CURRENT TEMPS REMAIN IN THE TEENS...15 AT ADRIAN. THUS...LOWEST OVERNIGHT LOWS ARE EXPECTED IN THAT AREA. THEN TEMPS ARE EXPECTED TO LEVEL OFF AND POSSIBLY CLIMB A LITTLE OVERNIGHT UNDER A WEAK WARM AIR ADVECTION REGIME. THE POTENTIAL FOR SCATTERED LIGHT SNOW SHOWERS ARRIVES AFTER MIDNIGHT AND WILL EXIST THROUGH THURSDAY. LIMITED MOISTURE AND A WEAKENING SYSTEM WILL KEEP SNOW SHOWERS ON THE LIGHT SIDE WITH LITTLE TO NO ACCUMULATION EXPECTED. THE SAGINAW VALLEY STANDS TO SEE THE BEST ACTIVITY AS THAT IS THE FAVORED AREA FOR LAKE LAKE ENHANCED SNOW SHOWERS WITHIN SOUTHWESTERLY FLOW REGIME. LATEST RUC ANALYSIS/SATELLITE DATA SUPPORTS THE MODELS CONSISTENT FORECAST OF THE SHORT WAVE SHEARING OUT WITHIN CONFLUENT FLOW ALOFT OVER THE GREAT LAKES EARLY THURSDAY MORNING. UPPER DIVERGENCE...WITHIN RIGHT ENTRANCE REGION OF DEPARTING JET STREAK... WILL BE SUPPORTIVE OF EXTRA LIFT OVERNIGHT...MAINLY ACROSS THE NORTH HALF OF THE CWA. MODEL SOUNDINGS INDICATE THAT THE VERY DRY 900 TO 700 MB COLUMN OF AIR WILL THEN MOISTEN UP CONSIDERABLY DURING THE EARLY MORNING HOURS. BUT WITH VERY LITTLE INSTABILITY AND LACK OF LOW LEVEL SUPPORT...ANY SNOW SHOWERS SHOULD REMAIN ON THE TAME SIDE. BY THE TIME BETTER LOW LEVEL SUPPORT ARRIVES ON THURSDAY...THE MID AND UPPER LEVEL MOISTURE WILL BEGIN TO STRIP AWAY AS THE UPPER SUPPORT BECOMES SHEARED OUT. HOWEVER WITH INVERSION HEIGHTS AROUND 800 MB ON THURSDAY NORTH OF DETROIT...LINGERING SNOW SHOWERS CANNOT BE RULED OUT. LONG TERM... THE PLAINS WAVE WILL HAVE SHEARED TO OUR EAST BY THURSDAY NIGHT LEAVING ONLY A CHANCE OF LIGHT SNOW SHOWERS OR FLURRIES UNTIL THE NEXT SYSTEM ARRIVES FROM CENTRAL CANADA ON FRIDAY. THIS FEATURE LOOKS TO BE HANDLED WELL JUDGING FROM SATELLITE IMAGERY TODAY BUT IT IS HARD TO GET EXCITED ABOUT THE PROSPECTS FOR SNOW AS IT MOVES THROUGH OUR AREA FRIDAY AFTERNOON. MID LEVEL MOISTURE WILL BE AT A PREMIUM AS THE WAVE WILL BE CUT OFF FROM BOTH GULF AND PACIFIC MOISTURE SOURCES. HOWEVER, A BOOST FROM LAKE MICHIGAN LOOKS REASONABLE AS THE COLD FRONT MOVES THROUGH LOWER MICHIGAN FRIDAY AFTERNOON AND EVENING. THIS IS WORTH CHANCE/SCATTERED POPS FOR SNOW SHOWERS. OUR FIRST SURGE OF ARCTIC AIR WILL ARRIVE BEHIND THIS SYSTEM FRIDAY NIGHT. THE 12Z MODELS ALL SHOW 850 MB TEMPS DROPPING TO AROUND -20C BY SUNRISE SATURDAY MORNING. A SW COMPONENT TO THE WIND WILL INITIALLY HELP WITH SINGLE DIGIT LOW TEMPERATURES, DESPITE SOME CLOUD COVER, AS COLDER SURFACE AIR FLOWS AROUND THE SOUTH END OF LAKE MICHIGAN AND INTO OUR AREA. HOWEVER, THIS SAME SW FLOW WILL STRENGTHEN AND ADVECT SOMEWHAT WARMER AIR INTO THE REGION AS THE SURFACE HIGH DRIFTS EAST AND AHEAD OF THE NEXT WAVE OF LOW PRESSURE SCHEDULED TO ARRIVE ON SATURDAY. IN THIS REGARD, GUIDANCE TEMPERATURES CALLING FOR HIGHS IN THE TEENS LOOK OK BUT THESE READINGS WILL BE ACCOMPANIED BY A 10 TO 20 MPH WIND AND WIND CHILLS NEAR 10 BELOW ZERO. THERE ARE SOME TIMING DIFFERENCES IN THE 12Z MODELS ON THE HANDLING OF THE SATURDAY WAVE. PREFER THE FASTER SOLUTIONS, OF WHICH THE GFS IS ONE, AS RENEWED HEIGHT FALLS GET UNDERWAY IN CENTRAL CANADA AND ANCHOR THE POLAR VORTEX OVER NORTHERN ONTARIO. THIS SYSTEM WILL BRING OUR BEST CHANCE OF SNOW DURING THE WEEKEND AND REPLENISH THE ARCTIC AIR MASS SATURDAY NIGHT AND SUNDAY. THIS WILL BE THE MOST BRUTAL PORTION OF THE COLD OUTBREAK WHEN FACTORING IN BOTH TEMPERATURE AND WIND TAKING WIND CHILL TO AROUND -20F. THE GFS FORECASTS 850 MB TEMPS TO DROP DOWN NEAR -28C WHICH CORRESPONDS TO DAYTIME TEMPERATURES NO BETTER THAN THE SINGLE DIGITS ON SUNDAY. IN FACT, DAYTIME TEMPERATURES TODAY IN REGIONS OF NORTHERN CANADA SHOW A FEW READINGS STILL BELOW ZERO WITH SIMILAR 850 MB TEMPERATURES. IN ADDITION, THERE WILL LIKELY BE CONSIDERABLY MORE OF A SURFACE PRESSURE TROUGH IN THE LEE OF LAKE MICHIGAN WHICH WILL DIRECT A SW FLOW OF LESS MODIFIED AIR INTO SE MICHIGAN. THE LAST TIME METRO DETROIT HAD AT LEAST TWO CONSECUTIVE DAYS OF SINGLE DIGIT HIGH TEMPERATURES WAS IN JANUARY 1994. VERY LITTLE TEMPERATURE MODERATION IS EXPECTED ON MONDAY AS THE CORE OF THE POLAR VORTEX MOVES OVER THE GREAT LAKES. THE GLOBAL MODELS DO SHOW THE VORTEX MOVING EAST BY TUESDAY BUT DEEP NW FLOW WILL CONTINUE THE SUPPLY OF ARCTIC AIR THROUGH THE MIDDLE OF NEXT WEEK. SOME MODERATION IS POSSIBLE ON TUESDAY AND WEDNESDAY AS THE WIND BACKS TOWARD THE WEST AND NORTHWEST, PREVENTING THE LESS MODIFIED AIR FROM MOVING INTO THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 3 PM THURSDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422... UNTIL 10 AM THURSDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY FOR WINDS...UNTIL 10 AM THURSDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FOR WINDS... && $$ AVIATION...DWD SHORT TERM...JDS LONG TERM....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 651 PM EST WED JAN 31 2007 .AVIATION... MID AND HIGH CLOUDS FORESEEN FOR MOST OF THE NIGHT...WITH THE MID CLOUDS THICKENING/LOWERING WITH TIME AS PER MODEL SOUNDINGS AND MOISTURE TIME SECTIONS. TOWARD DAYBREAK AT KMBS AND EARLY FORENOON AT THE OTHER SITES...EXPECT LOWERING CEILINGS INTO MVFR AS DEARTH OF LOW LEVEL MOISTURE ENDS...WITH THE NORTH AIDED BY TRAJECTORY OFF OF LAKE MICHIGAN. NEARLY ADIABATIC LOW LEVEL LAPSE RATES DEVELOPING THURSDAY AS COLD TEMPERATURES ALOFT PROMOTE EXPECT DIURNAL BOOST FOR SNOW SHOWERS. TAFS ARE INDICATING A PROB30 GROUP BETWEEN 17Z TO 21Z OR 18Z TO 22Z FOR MVFR IN SNOW SHOWERS. NOT ENOUGH CONFIDENCE IN POTENTIAL TONIGHT TO MENTION ANY PRECIPITATION...AS LOW LEVEL MOISTURE WILL BE SPARSE. && .PREV DISCUSSION...ISSUED 434 PM EST WED JAN 31 2007 SHORT TERM...TONIGHT AND THURSDAY OVERNIGHT LOWS LIKELY TO OCCUR SHORTLY AFTER SUNSET...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE AREA WHERE CURRENT TEMPS REMAIN IN THE TEENS...15 AT ADRIAN. THUS...LOWEST OVERNIGHT LOWS ARE EXPECTED IN THAT AREA. THEN TEMPS ARE EXPECTED TO LEVEL OFF AND POSSIBLY CLIMB A LITTLE OVERNIGHT UNDER A WEAK WARM AIR ADVECTION REGIME. THE POTENTIAL FOR SCATTERED LIGHT SNOW SHOWERS ARRIVES AFTER MIDNIGHT AND WILL EXIST THROUGH THURSDAY. LIMITED MOISTURE AND A WEAKENING SYSTEM WILL KEEP SNOW SHOWERS ON THE LIGHT SIDE WITH LITTLE TO NO ACCUMULATION EXPECTED. THE SAGINAW VALLEY STANDS TO SEE THE BEST ACTIVITY AS THAT IS THE FAVORED AREA FOR LAKE LAKE ENHANCED SNOW SHOWERS WITHIN SOUTHWESTERLY FLOW REGIME. LATEST RUC ANALYSIS/SATELLITE DATA SUPPORTS THE MODELS CONSISTENT FORECAST OF THE SHORT WAVE SHEARING OUT WITHIN CONFLUENT FLOW ALOFT OVER THE GREAT LAKES EARLY THURSDAY MORNING. UPPER DIVERGENCE...WITHIN RIGHT ENTRANCE REGION OF DEPARTING JET STREAK... WILL BE SUPPORTIVE OF EXTRA LIFT OVERNIGHT...MAINLY ACROSS THE NORTH HALF OF THE CWA. MODEL SOUNDINGS INDICATE THAT THE VERY DRY 900 TO 700 MB COLUMN OF AIR WILL THEN MOISTEN UP CONSIDERABLY DURING THE EARLY MORNING HOURS. BUT WITH VERY LITTLE INSTABILITY AND LACK OF LOW LEVEL SUPPORT...ANY SNOW SHOWERS SHOULD REMAIN ON THE TAME SIDE. BY THE TIME BETTER LOW LEVEL SUPPORT ARRIVES ON THURSDAY...THE MID AND UPPER LEVEL MOISTURE WILL BEGIN TO STRIP AWAY AS THE UPPER SUPPORT BECOMES SHEARED OUT. HOWEVER WITH INVERSION HEIGHTS AROUND 800 MB ON THURSDAY NORTH OF DETROIT...LINGERING SNOW SHOWERS CANNOT BE RULED OUT. LONG TERM... THE PLAINS WAVE WILL HAVE SHEARED TO OUR EAST BY THURSDAY NIGHT LEAVING ONLY A CHANCE OF LIGHT SNOW SHOWERS OR FLURRIES UNTIL THE NEXT SYSTEM ARRIVES FROM CENTRAL CANADA ON FRIDAY. THIS FEATURE LOOKS TO BE HANDLED WELL JUDGING FROM SATELLITE IMAGERY TODAY BUT IT IS HARD TO GET EXCITED ABOUT THE PROSPECTS FOR SNOW AS IT MOVES THROUGH OUR AREA FRIDAY AFTERNOON. MID LEVEL MOISTURE WILL BE AT A PREMIUM AS THE WAVE WILL BE CUT OFF FROM BOTH GULF AND PACIFIC MOISTURE SOURCES. HOWEVER, A BOOST FROM LAKE MICHIGAN LOOKS REASONABLE AS THE COLD FRONT MOVES THROUGH LOWER MICHIGAN FRIDAY AFTERNOON AND EVENING. THIS IS WORTH CHANCE/SCATTERED POPS FOR SNOW SHOWERS. OUR FIRST SURGE OF ARCTIC AIR WILL ARRIVE BEHIND THIS SYSTEM FRIDAY NIGHT. THE 12Z MODELS ALL SHOW 850 MB TEMPS DROPPING TO AROUND -20C BY SUNRISE SATURDAY MORNING. A SW COMPONENT TO THE WIND WILL INITIALLY HELP WITH SINGLE DIGIT LOW TEMPERATURES, DESPITE SOME CLOUD COVER, AS COLDER SURFACE AIR FLOWS AROUND THE SOUTH END OF LAKE MICHIGAN AND INTO OUR AREA. HOWEVER, THIS SAME SW FLOW WILL STRENGTHEN AND ADVECT SOMEWHAT WARMER AIR INTO THE REGION AS THE SURFACE HIGH DRIFTS EAST AND AHEAD OF THE NEXT WAVE OF LOW PRESSURE SCHEDULED TO ARRIVE ON SATURDAY. IN THIS REGARD, GUIDANCE TEMPERATURES CALLING FOR HIGHS IN THE TEENS LOOK OK BUT THESE READINGS WILL BE ACCOMPANIED BY A 10 TO 20 MPH WIND AND WIND CHILLS NEAR 10 BELOW ZERO. THERE ARE SOME TIMING DIFFERENCES IN THE 12Z MODELS ON THE HANDLING OF THE SATURDAY WAVE. PREFER THE FASTER SOLUTIONS, OF WHICH THE GFS IS ONE, AS RENEWED HEIGHT FALLS GET UNDERWAY IN CENTRAL CANADA AND ANCHOR THE POLAR VORTEX OVER NORTHERN ONTARIO. THIS SYSTEM WILL BRING OUR BEST CHANCE OF SNOW DURING THE WEEKEND AND REPLENISH THE ARCTIC AIR MASS SATURDAY NIGHT AND SUNDAY. THIS WILL BE THE MOST BRUTAL PORTION OF THE COLD OUTBREAK WHEN FACTORING IN BOTH TEMPERATURE AND WIND TAKING WIND CHILL TO AROUND -20F. THE GFS FORECASTS 850 MB TEMPS TO DROP DOWN NEAR -28C WHICH CORRESPONDS TO DAYTIME TEMPERATURES NO BETTER THAN THE SINGLE DIGITS ON SUNDAY. IN FACT, DAYTIME TEMPERATURES TODAY IN REGIONS OF NORTHERN CANADA SHOW A FEW READINGS STILL BELOW ZERO WITH SIMILAR 850 MB TEMPERATURES. IN ADDITION, THERE WILL LIKELY BE CONSIDERABLY MORE OF A SURFACE PRESSURE TROUGH IN THE LEE OF LAKE MICHIGAN WHICH WILL DIRECT A SW FLOW OF LESS MODIFIED AIR INTO SE MICHIGAN. THE LAST TIME METRO DETROIT HAD AT LEAST TWO CONSECUTIVE DAYS OF SINGLE DIGIT HIGH TEMPERATURES WAS IN JANUARY 1994. VERY LITTLE TEMPERATURE MODERATION IS EXPECTED ON MONDAY AS THE CORE OF THE POLAR VORTEX MOVES OVER THE GREAT LAKES. THE GLOBAL MODELS DO SHOW THE VORTEX MOVING EAST BY TUESDAY BUT DEEP NW FLOW WILL CONTINUE THE SUPPLY OF ARCTIC AIR THROUGH THE MIDDLE OF NEXT WEEK. SOME MODERATION IS POSSIBLE ON TUESDAY AND WEDNESDAY AS THE WIND BACKS TOWARD THE WEST AND NORTHWEST, PREVENTING THE LESS MODIFIED AIR FROM MOVING INTO THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 3 PM THURSDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422... UNTIL 10 AM THURSDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY FOR WINDS...UNTIL 10 AM THURSDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FOR WINDS... && $$ AVIATION...DWD SHORT TERM...JDS LONG TERM....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 434 PM EST WED JAN 31 2007 .SHORT TERM...TONIGHT AND THURSDAY OVERNIGHT LOWS LIKELY TO OCCUR SHORTLY AFTER SUNSET...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE AREA WHERE CURRENT TEMPS REMAIN IN THE TEENS...15 AT ADRIAN. THUS...LOWEST OVERNIGHT LOWS ARE EXPECTED IN THAT AREA. THEN TEMPS ARE EXPECTED TO LEVEL OFF AND POSSIBLY CLIMB A LITTLE OVERNIGHT UNDER A WEAK WARM AIR ADVECTION REGIME. THE POTENTIAL FOR SCATTERED LIGHT SNOW SHOWERS ARRIVES AFTER MIDNIGHT AND WILL EXIST THROUGH THURSDAY. LIMITED MOISTURE AND A WEAKENING SYSTEM WILL KEEP SNOW SHOWERS ON THE LIGHT SIDE WITH LITTLE TO NO ACCUMULATION EXPECTED. THE SAGINAW VALLEY STANDS TO SEE THE BEST ACTIVITY AS THAT IS THE FAVORED AREA FOR LAKE LAKE ENHANCED SNOW SHOWERS WITHIN SOUTHWESTERLY FLOW REGIME. LATEST RUC ANALYSIS/SATELLITE DATA SUPPORTS THE MODELS CONSISTENT FORECAST OF THE SHORT WAVE SHEARING OUT WITHIN CONFLUENT FLOW ALOFT OVER THE GREAT LAKES EARLY THURSDAY MORNING. UPPER DIVERGENCE...WITHIN RIGHT ENTRANCE REGION OF DEPARTING JET STREAK... WILL BE SUPPORTIVE OF EXTRA LIFT OVERNIGHT...MAINLY ACROSS THE NORTH HALF OF THE CWA. MODEL SOUNDINGS INDICATE THAT THE VERY DRY 900 TO 700 MB COLUMN OF AIR WILL THEN MOISTEN UP CONSIDERABLY DURING THE EARLY MORNING HOURS. BUT WITH VERY LITTLE INSTABILITY AND LACK OF LOW LEVEL SUPPORT...ANY SNOW SHOWERS SHOULD REMAIN ON THE TAME SIDE. BY THE TIME BETTER LOW LEVEL SUPPORT ARRIVES ON THURSDAY...THE MID AND UPPER LEVEL MOISTURE WILL BEGIN TO STRIP AWAY AS THE UPPER SUPPORT BECOMES SHEARED OUT. HOWEVER WITH INVERSION HEIGHTS AROUND 800 MB ON THURSDAY NORTH OF DETROIT...LINGERING SNOW SHOWERS CANNOT BE RULED OUT. && .LONG TERM...THE PLAINS WAVE WILL HAVE SHEARED TO OUR EAST BY THURSDAY NIGHT LEAVING ONLY A CHANCE OF LIGHT SNOW SHOWERS OR FLURRIES UNTIL THE NEXT SYSTEM ARRIVES FROM CENTRAL CANADA ON FRIDAY. THIS FEATURE LOOKS TO BE HANDLED WELL JUDGING FROM SATELLITE IMAGERY TODAY BUT IT IS HARD TO GET EXCITED ABOUT THE PROSPECTS FOR SNOW AS IT MOVES THROUGH OUR AREA FRIDAY AFTERNOON. MID LEVEL MOISTURE WILL BE AT A PREMIUM AS THE WAVE WILL BE CUT OFF FROM BOTH GULF AND PACIFIC MOISTURE SOURCES. HOWEVER, A BOOST FROM LAKE MICHIGAN LOOKS REASONABLE AS THE COLD FRONT MOVES THROUGH LOWER MICHIGAN FRIDAY AFTERNOON AND EVENING. THIS IS WORTH CHANCE/SCATTERED POPS FOR SNOW SHOWERS. OUR FIRST SURGE OF ARCTIC AIR WILL ARRIVE BEHIND THIS SYSTEM FRIDAY NIGHT. THE 12Z MODELS ALL SHOW 850 MB TEMPS DROPPING TO AROUND -20C BY SUNRISE SATURDAY MORNING. A SW COMPONENT TO THE WIND WILL INITIALLY HELP WITH SINGLE DIGIT LOW TEMPERATURES, DESPITE SOME CLOUD COVER, AS COLDER SURFACE AIR FLOWS AROUND THE SOUTH END OF LAKE MICHIGAN AND INTO OUR AREA. HOWEVER, THIS SAME SW FLOW WILL STRENGTHEN AND ADVECT SOMEWHAT WARMER AIR INTO THE REGION AS THE SURFACE HIGH DRIFTS EAST AND AHEAD OF THE NEXT WAVE OF LOW PRESSURE SCHEDULED TO ARRIVE ON SATURDAY. IN THIS REGARD, GUIDANCE TEMPERATURES CALLING FOR HIGHS IN THE TEENS LOOK OK BUT THESE READINGS WILL BE ACCOMPANIED BY A 10 TO 20 MPH WIND AND WIND CHILLS NEAR 10 BELOW ZERO. THERE ARE SOME TIMING DIFFERENCES IN THE 12Z MODELS ON THE HANDLING OF THE SATURDAY WAVE. PREFER THE FASTER SOLUTIONS, OF WHICH THE GFS IS ONE, AS RENEWED HEIGHT FALLS GET UNDERWAY IN CENTRAL CANADA AND ANCHOR THE POLAR VORTEX OVER NORTHERN ONTARIO. THIS SYSTEM WILL BRING OUR BEST CHANCE OF SNOW DURING THE WEEKEND AND REPLENISH THE ARCTIC AIR MASS SATURDAY NIGHT AND SUNDAY. THIS WILL BE THE MOST BRUTAL PORTION OF THE COLD OUTBREAK WHEN FACTORING IN BOTH TEMPERATURE AND WIND TAKING WIND CHILL TO AROUND -20F. THE GFS FORECASTS 850 MB TEMPS TO DROP DOWN NEAR -28C WHICH CORRESPONDS TO DAYTIME TEMPERATURES NO BETTER THAN THE SINGLE DIGITS ON SUNDAY. IN FACT, DAYTIME TEMPERATURES TODAY IN REGIONS OF NORTHERN CANADA SHOW A FEW READINGS STILL BELOW ZERO WITH SIMILAR 850 MB TEMPERATURES. IN ADDITION, THERE WILL LIKELY BE CONSIDERABLY MORE OF A SURFACE PRESSURE TROUGH IN THE LEE OF LAKE MICHIGAN WHICH WILL DIRECT A SW FLOW OF LESS MODIFIED AIR INTO SE MICHIGAN. THE LAST TIME METRO DETROIT HAD AT LEAST TWO CONSECUTIVE DAYS OF SINGLE DIGIT HIGH TEMPERATURES WAS IN JANUARY 1994. VERY LITTLE TEMPERATURE MODERATION IS EXPECTED ON MONDAY AS THE CORE OF THE POLAR VORTEX MOVES OVER THE GREAT LAKES. THE GLOBAL MODELS DO SHOW THE VORTEX MOVING EAST BY TUESDAY BUT DEEP NW FLOW WILL CONTINUE THE SUPPLY OF ARCTIC AIR THROUGH THE MIDDLE OF NEXT WEEK. SOME MODERATION IS POSSIBLE ON TUESDAY AND WEDNESDAY AS THE WIND BACKS TOWARD THE WEST AND NORTHWEST, PREVENTING THE LESS MODIFIED AIR FROM MOVING INTO THE REGION. && .AVIATION...ISSUED AT 104 PM EST SOUTHWEST FLOW AND WEAK WARM AIR ADVECTION WILL CONTINUE TO SUPPORT MID CLOUDS TODAY. MARINE CLOUDS TO CONTINUE THIS AFTERNOON AT THE FNT AND MBS TERMINALS...WITH MVFR CEILINGS EXPECTED PERIODICALLY. MVFR CEILINGS TO MOVE IN AGAIN AND BECOME MORE WIDESPREAD AFTER MIDNIGHT...IN ASSOCIATION WITH THE APPROACH OF A WEAK CLIPPER SYSTEM. MVFR CEILINGS ARE THEN EXPECTED TO REMAIN IN PLACE THROUGH THIS TAF PERIOD. THERE WILL BE SCATTERED LIGHT SNOW SHOWERS AROUND ON THURSDAY. SOUTHWESTERLY FLOW TO PROVIDE FNT AND MBS WITH AN OPPORTUNITY FOR SOME LAKE ENHANCED SNOW SHOWERS...THUS THE REASONING FOR A PERIOD OF MVFR VISIBILITIES IN THAT AREA. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN T THURSDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422 UNTIL 10 AM THURSDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY FOR WINDS...LCZ460 UNTIL 10 AM THURSDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FOR WINDS...UNTIL 10 AM THURSDAY. && $$ SHORT TERM...JDS LONG TERM....BT AVIATION...JDS YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 335 PM CST THU FEB 1 2007 .DISCUSSION... EARLY AFTERNOON SURFACE OBS ILLUSTRATE THE COLD FRONT STRETCHING FROM LAKE SUPERIOR TO THE TWIN CITIES AND FAIRMONT...WHILE WATER VAPOR IMAGERY SHOWS A MID LEVEL TROUGH PLUNGING INTO THE NORTHERN PLAINS. ASSOCIATED LIGHT SNOW CORRELATES WELL WITH RUC PROGGED 700-500MB Q VECTOR CONVERGENCE AND ISENTROPIC UPGLIDE ON THE GFS 280K SURFACE. THESE FEATURES...ALONG WITH WEAK 850-750MB 2D FRONTOGENESIS...SWING EAST/SOUTHEAST ACROSS THE FORECAST THIS EVENING AND TONIGHT. WHILE FORECAST POPS ARE HIGH...ACCUMULATIONS WILL BE LIGHT AND GENERALLY UNDER AN INCH. STRONG COLD AIR ADVECTION AND PRESSURE RISES WILL ENSUE TONIGHT IN THE WAKE OF THE FRONT...ESPECIALLY ACROSS WESTERN AND SOUTH CENTRAL MINNESOTA. BRISK WINDS SUSTAINED IN THE 15 TO 25 MPH RANGE WITH GUSTS TO 30 MPH WILL PERSIST TONIGHT. EXPECT CLOUDS TO PARTIALLY SCATTER OUT TONIGHT...WITH TEMPERATURES PLUMMETING TO BETWEEN ZERO AND 10 BELOW. HAVE LEANED TOWARD THE COLD SIDE OF NUMERICAL GUIDANCE...DUE TO THE EXPECTED SCATTERING TREND. THE COMBINATION OF BREEZY WINDS AND SUB-ZERO TEMPS WILL YIELD WIND CHILLS READINGS IN THE 25-35 BELOW RANGE ACROSS THE WESTERN THREE QUARTERS OF THE CWA THROUGH FRIDAY MORNING...WHERE/WHEN AN ADVISORY HAS BEEN ISSUED. EXPECT A RESPITE FROM ADVISORY LEVEL /-25 AND BELOW/ WIND CHILL VALUES ON FRIDAY AFTERNOON...BUT SUBSEQUENT WIND CHILL HEADLINES WILL LIKELY BE NEEDED OVER THE WEEKEND FOR THE EVENING-MORNING TIMEFRAMES. ANOTHER WEAK SHORTWAVE/FRONT WILL ARRIVE FRIDAY AFTERNOON/NIGHT...WHERE 30 POPS HAVE BEEN MAINTAINED. SNOWFALL ACCUMULATIONS SHOULD BE MINIMAL DUE TO THE WEAK NATURE OF THE LIFT ACCOMPANYING THIS WAVE. 925MB TEMPERATURES DROP TO -24C TO -26C BY SATURDAY AND STAY INTO NEXT WEEK. MOST LOCATIONS WILL NOT RISE ABOVE THE ZERO DEGREE MARK FOR THE ENTIRE WEEKEND. A BROAD TROUGH WILL PLAGUE THE EASTERN HALF OF THE CONUS INTO THE MIDDLE OF NEXT WEEK. WHILE HIGH TEMPERATURES WILL MODERATE GRADUALLY EACH DAY NEXT WEEK...LOW TEMPERATURES WILL STILL BE IN THE 10 TO 15 BELOW RANGE THROUGH WEDNESDAY. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 12 PM CST FRIDAY FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-DAKOTA- DOUGLAS-FARIBAULT-FREEBORN-HENNEPIN-ISANTI-KANABEC- KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE- SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD- WASECA-WATONWAN-WRIGHT-YELLOW MEDICINE COUNTY(IES). WI...NONE. && $$ LS mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 335 PM CST THU FEB 1 2007 .DISCUSSION... EARLY AFTERNOON SURFACE OBS ILLUSTRATE THE COLD FRONT STRETCHING FROM LAKE SUPERIOR TO THE TWIN CITIES AND FAIRMONT...WHILE WATER VAPOR IMAGERY SHOWS A MID LEVEL TROUGH PLUNGING INTO THE NORTHERN PLAINS. ASSOCIATED LIGHT SNOW CORRELATES WELL WITH RUC PROGGED 700-500MB Q VECTOR CONVERGENCE AND ISENTROPIC UPGLIDE ON THE GFS 280K SURFACE. THESE FEATURES...ALONG WITH WEAK 850-750MB 2D FRONTOGENESIS...SWING EAST/SOUTHEAST ACROSS THE FORECAST THIS EVENING AND TONIGHT. WHILE FORECAST POPS ARE HIGH...ACCUMULATIONS WILL BE LIGHT AND GENERALLY UNDER AN INCH. STRONG COLD AIR ADVECTION AND PRESSURE RISES WILL ENSUE TONIGHT IN THE WAKE OF THE FRONT...ESPECIALLY ACROSS WESTERN AND SOUTH CENTRAL MINNESOTA. BRISK WINDS SUSTAINED IN THE 15 TO 25 MPH RANGE WITH GUSTS TO 30 MPH WILL PERSIST TONIGHT. EXPECT CLOUDS TO PARTIALLY SCATTER OUT TONIGHT...WITH TEMPERATURES PLUMMETING TO BETWEEN ZERO AND 10 BELOW. HAVE LEANED TOWARD THE COLD SIDE OF NUMERICAL GUIDANCE...DUE TO THE EXPECTED SCATTERING TREND. THE COMBINATION OF BREEZY WINDS AND SUB-ZERO TEMPS WILL YIELD WIND CHILLS READINGS IN THE 25-35 BELOW RANGE ACROSS THE WESTERN THREE QUARTERS OF THE CWA THROUGH FRIDAY MORNING...WHERE/WHEN AN ADVISORY HAS BEEN ISSUED. EXPECT A RESPITE FROM ADVISORY LEVEL /-25 AND BELOW/ WIND CHILL VALUES ON FRIDAY AFTERNOON...BUT SUBSEQUENT WIND CHILL HEADLINES WILL LIKELY BE NEEDED OVER THE WEEKEND FOR THE EVENING-MORNING TIMEFRAMES. ANOTHER WEAK SHORTWAVE/FRONT WILL ARRIVE FRIDAY AFTERNOON/NIGHT...WHERE 30 POPS HAVE BEEN MAINTAINED. SNOWFALL ACCUMULATIONS SHOULD BE MINIMAL DUE TO THE WEAK NATURE OF THE LIFT ACCOMPANYING THIS WAVE. 925MB TEMPERATURES DROP TO -24C TO -26C BY SATURDAY AND STAY INTO NEXT WEEK. MOST LOCATIONS WILL NOT RISE ABOVE THE ZERO DEGREE MARK FOR THE ENTIRE WEEKEND. A BROAD TROUGH WILL PLAGUE THE EASTERN HALF OF THE CONUS INTO THE MIDDLE OF NEXT WEEK. WHILE HIGH TEMPERATURES WILL MODERATE GRADUALLY EACH DAY NEXT WEEK...LOW TEMPERATURES WILL STILL BE IN THE 10 TO 15 BELOW RANGE THROUGH WEDNESDAY. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 12 PM CST FRIDAY FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-DAKOTA- DOUGLAS-FARIBAULT-FREEBORN-HENNEPIN-ISANTI-KANABEC- KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE- SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD- WASECA-WATONWAN-WRIGHT-YELLOW MEDICINE COUNTY(IES). WI...NONE. && $$ LS mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 335 PM CST WED JAN 31 2007 .DISCUSSION... BAND OF SNOW WITH FAIRLY SIG 850-700 MB THETA E ADVECTION AS DEPICTED BUT RUC HAS MOSTLY MOVED OFF INTO WI BUT REMAINS OF UPPER TROF MOVING ACROSS REST OF AREA THIS EVENING. FAIRLY SIG TROP LOWERING WITH THIS TROF..AND SIMILAR FORCING WILL BE MOVING INTO THE AREA BY THURSDAY AFTERNOON AND AGAIN FRIDAY AFTERNOON. WILL FOLLOW THE GFS ON TIMING AND IS VERY CLOSE TO ECMWF/UKMET. THE FIRST BLAST OF COLD AIR ARRIVES THURSDAY NIGHT...BUT THE STRONGER SURGE WILL BE FRIDAY NIGHT...WITH MORE DANGEROUS WIND CHILLS. THE UPPER JET WILL BE CLOSER TO THE AXIS OF STRONG LOW LEVEL COLD ADVECTION ON FRIDAY NIGHT. STILL MAY NEED AN ADVISORY IN WESTERN CWA ON THURSDAY NIGHT WITH THE COLD ADVECTION/WIND CHILLS/BLOWING SNOW POTENTIAL. THE LIKELY POPS STILL LOOK GOOD FOR THE TROUGH THURSDAY AFTERNOON/NIGHT BUT WILL SPEED UP THE ONSET A BIT. HAVE PAINTED IN A SMALL POP/ABOVE GUID/ FOR FRIDAY AFTERNOON/NIGHT BASED ON THE ABOVE MENTIONED FORCING AS WELL. THE ARCTIC AIR REMAINS ENTRENCHED FOR THE FIRST PART OF THE WEEK WITH MOSTLY CLEAR SKIES. HAVE DECREASED CLOUD COVER DRAMATICALLY IN THE SKY GRIDS WITH THE ARCTIC AIR IN PLACE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 830 PM CST WED JAN 31 2007 .DISCUSSION...SO FAR THE FORECAST LOOKS ON TRACK. AFTER AN EARLIER UPDATE TO EXPAND THE ADV AREA FOR THREE MORE COUNTIES THE FORECAST HAS GONE ABOUT AS EXPECTED. MOST PLACES ACROSS NRN MS AND SERN AR HAVE REPORTED SLEET WITH EVEN SOME LIGHT SN AT THE ONSET. THE WAY EVERYTHING IS GOING WE WILL LIKELY NEED TO SEE THE INTENSITY PICK UP BEFORE WE START TO SEE ANY ISSUES ACROSS OUR NORTH. THIS WILL LIKELY HAPPEN IN A FEW HRS AS HEAVIER BANDS OF PRECIP HAVE BEEN WORKING NE THROUGH WRN LOUISIANA FROM THE COAST. LOOK FOR THESE BANDS TO MOVE INTO THE DELTA AREA AROUND 4Z WITH MODERATE SLEET...SNOW TO START. IT STILL LOOKS LIKE THE SRN 2/3RDS OF THE CWA WILL ALL TRANSITION TO LIQUID AFTER MIDNIGHT. THE NRN 3RD COULD BECOME TRICKY AS THE LL WARM PROVIDING MORE OF A CONCERN FOR FZRA AFTER MIDNIGHT. THIS IS ESPECIALLY SO NORTH OF THE HWY 82 CORRIDOR AROUND LOCATIONS LIKE CLEVELAND AND GRENADA WHERE THE RUC SNDGS SHOW THE POSSIBILITY OF FZRA FOR A 3 TO 6 HRS. WILL KEEP AN EYE ON THIS TO SEE IF ANY UPDATES NEED TO BE MADE TO THE FORECAST AND ADV. NO UPDATE NEEDED TO THE ZFP OR GRIDS AT THIS TIME. /CAB/ && .PREV DISCUSSION...ADVISORY ISSUED FOR NRN TIER ZONES FOR WINTER WEATHER TONIGHT. WILL SEE A RAIN/SLEET MIX AS FAR SOUTH AS INTERSTATE 20 TONIGHT BUT THE BEST CHANCE FOR LIGHT ACCUMULATION WILL BE IN THE COLDEST AIR THAT SITS ALONG THE NRN EDGE OF THE FORECAST AREA. A COLD AND VERY DRY AIR MASS HAS SETTLED OVER THE REGION. EVAPORATIVE COOLING WILL PRODUCE FREEZING TEMPERATURES AT AND JUST ABOVE THE SURFACE OVER NRN ZONES AT THE ONSET OF PRECIP THIS EVENING. FREEZING TEMPERATURES IN THE ADVISORY AREA...FROM CLEVELAND TO COLUMBUS...WILL BE DEEP ENOUGH FOR A MIXTURE OF SNOW AND SLEET EARLY TONIGHT. THE TIER FURTHER S WILL SEE RAIN AND SLEET MIXED WITH SNOW AND FREEZING RAIN BUT LITTLE OR NO ACCUMULATION OF WINTER PRECIP IS EXPECTED. WET BULB ZERO TEMPS WILL HOVER IN A LAYER ABOVE THE SURFACE INTO CENTRAL ZONES RESULTING IN THE POSSIBILITY OF A RAIN AND SLEET MIXTURE INTO THE I-20 CORRIDOR BUT SLEET WILL MELT RAPIDLY ON CONTACT WITH THE GROUND. THE ADVECTION OF WARMER AIR AROUND 850 MB AND COOLING OF LOWER LEVELS NEAR THE SURFACE AFTER THE ONSET OF RAIN HAS REQUIRED A VARIED PATTERN OF WEATHER TYPES FROM NORTH TO SOUTH FOR TONIGHT. DIFFERENCES IN FORECAST TEMPERATURES...ESPECIALLY AT THE SURFACE...OF ONLY A DEGREE OR TWO WILL MEAN A POTENTIAL CHANGE IN THE WEATHER TYPE FOR MANY NRN AND CENTRAL ZONES. PRECIP HAS DEVELOPED OVER WRN ZONES THIS AFTERNOON WITH RAIN/SLEET MIXTURE ALREADY REPORTED OVER NE LA. TEMPERATURES WILL BEGIN TO INCREASE BY MIDNIGHT OVER MOST AREAS WHEN THE AIR COLUMN BEGINS TO MOISTEN AND EVAPORATIVE COOLING IS SHUT DOWN. WE WILL MAINTAIN A CHANCE OF A RAIN/SLEET MIX FOR AREAS ALONG AND N OF THE HIGHWAY 82 CORRIDOR AFTER MIDNIGHT BUT MOST OTHER AREAS WILL SEE PRECIP TURN TO ALL RAIN BY OR SHORTLY AFTER MIDNIGHT. RAIN WILL BE WIDESPREAD OVER THE FORECAST AREA BY SUNRISE THURSDAY AND TEMPERATURES WILL BE ABOVE FREEZING ACROSS THE REGION. THE SURFACE TROUGH LIFTS INTO SRN ZONES BY THURSDAY AFTERNOON... POSITIONING THE ASSOCIATED WARM FRONT IN SE MS BY 18Z. WILL MAINTAIN CHANCE OF THUNDERSTORMS THOSE AREAS TOMORROW AFTERNOON BUT THE TRACK LOOKS TOO FAR S TO SUPPORT ENOUGH INSTABILITY FOR SEVERE CONVECTION. UNDERCUT MOS HIGH TEMPS SLIGHTLY FOR TOMORROW CONSIDERING RAIN SHIELD AND SRN EXTENT OF SURFACE TROUGH. THE BOUNDARY IS EXPECTED TO MOVE THROUGH THE AREA BY THURSDAY EVENING. BEHIND THIS SYSTEM...SFC HIGH PRESSURE OVER THE GREAT PLAINS STATES WILL BEGIN TO MOVE INTO THE AREA FROM THE NORTHWEST. ISENTROPIC ANALYSIS AT THE 285-295K LEVEL AND REMAINING MOISTURE (PWATS AROUND 0.5-0.8 INCH) SHOW A SLIGHT CHANCE FOR SHOWERS FOR FRIDAY...MAINLY IN THE MORNING. WENT AHEAD AND STAYED WITH GUI FOR THU NIGHT INTO SATURDAY MORNING. ANY SHOWERS WILL NOT LAST LONG AS THE ECMWF AND GFS BOTH SHOW HIGH PRESSURE AND NORTHWEST FLOW ALOFT TAKING OVER THE REGION TO START CLEARING OVER THE ARKLAMISS BY SATURDAY AFTERNOON. THE ARCTIC AIRMASS THAT IS MOVING INTO THE REGION WILL COMBINE WITH CLEAR SKIES TO ALLOW LOW TEMPERATURES TO AGAIN DIP DOWN INTO THE 20S FOR THE END OF THE WEEKEND INTO THE BEGINNING OF THE WORK WEEK. THE MAIN CHANGES MADE TO TEMPERATURES WERE TO LOWER JUST A BIT ON FRIDAY NIGHT. SKIES WILL BE CLEARING AS HIGH PRESSURE MOVES IN...AND 925MB TEMPS LOOK TO RANGE FROM 0C TO -8C FOR THIS TIME PERIOD. DECIDED TO JUST BUMP TEMPERATURES DOWN A DEGREE OR TWO FOR THIS TIME PERIOD. FOR THE EXTENDED PORTION OF THE FORECAST (PAST SATURDAY NIGHT)...NO MAJOR CHANGES WERE NECESSARY. THE PREVIOUS LONG TERM DISCUSSION FOLLOWS. /14/ PREVIOUS LONG TERM DISCUSSION...THE DOMINANT HUDSON BAY LOW PATTERN WILL CONTINUE TO BRING SEVERAL COLD EPISODES FOR THE NEXT ONE TO TWO WEEKS IN MOSTLY DRY NORTHWEST FLOW. WITHOUT MUCH TO FOCUS ON PRECIP-WISE...THE PRIMARY FORECAST QUESTIONS CONCERN THE INTENSITY OF COLD AS THE FORECAST AREA WILL EXIST ON THE SRN EDGE OF THE POLAR VORTEX. AT THIS TIME...IT LOOKS AS IF THE CENTER OF COLD AIR ANOMALIES WILL STAY NORTH OF THE REGION...BUT THE NEXT FEW SURGES OF COLD AIR WILL BE SHALLOW AND OF TRUE ARCTIC ORIGINS FROM NEAR THE NORTH POLE. GIVEN RECENT GFS PERFORMANCES WITH SUCH AIRMASSES...HAVE OPTED TO TREND TOWARD COOLER GFS MEAN ENSEMBLE GUIDANCE AND CUT MEX GUIDANCE FROM FRIDAY NIGHT ONWARD (AT LEAST FOR PORTIONS OF THE FORECAST AREA). /EC/ && .AVIATION...WIDESPREAD WINTER PRECIP WILL DEVELOP ACROSS THE REGION THIS EVENING ALONG AND NORTH OF INTERSTATE 20 WITH THE BEST COVERAGE OVER AREAS ALONG AND NORTH OF HIGHWAY 82. HAVE RECEIVED REPORTS OF SLEET OVER NE LA AND TVR THIS AFTERNOON AS INITIAL PRECIP AREA MOVES IN. CLOUD HEIGHTS WILL GRADUALLY DROP AS PRECIP INCREASES IN COVERAGE AND INTENSITY TONIGHT WITH MVFR CONDITIONS MANY LOCATIONS BY MIDNIGHT AND IFR CONDITIONS BY SUNRISE. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 36 45 36 51 / 98 97 25 16 MERIDIAN 35 49 37 53 / 100 96 33 16 VICKSBURG 36 42 37 50 / 96 89 25 17 HATTIESBURG 40 53 39 57 / 100 99 29 16 NATCHEZ 38 46 34 53 / 98 91 22 16 GREENVILLE 32 38 33 43 / 99 95 39 18 GREENWOOD 30 39 34 46 / 100 97 37 18 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR MSZ018-019- 025>034. LA...NONE. AR...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR ARZ074-075. && $$ 03/14 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 725 PM CST WED JAN 31 2007 .DISCUSSION...DOING A QUICK UPDATE TO INCLUDE EXTREME SOUTHEASTERN ARKANSAS AND WASHINGTON COUNTY IN THE WINTER WEATHER ADVISORY. CURRENT OBS AND RUC DATA SHOWS THAT FROZEN PRECIP MAY BECOME MORE OF A PROBLEM IN THOSE AREAS. RUC IS NOW SHOWING THE WET BULB ZERO LINE SOUTH TO THE LA BORDER AND DUE EAST ACROSS CENTRAL MS. DECENT PRECIP IS CURRENTLY MOVING ACROSS THE DELTA WITH ANOTHER BATCH OF PRECIP HOT ON ITS HEELS. THIS WILL LIKELY CAUSE HAZARDOUS CONDITIONS ON BRIDGES AND EXPOSED SFCS IN THE NEXT FEW HRS. /CAB/ && .PREV DISCUSSION...ADVISORY ISSUED FOR NRN TIER ZONES FOR WINTER WEATHER TONIGHT. WILL SEE A RAIN/SLEET MIX AS FAR SOUTH AS INTERSTATE 20 TONIGHT BUT THE BEST CHANCE FOR LIGHT ACCUMULATION WILL BE IN THE COLDEST AIR THAT SITS ALONG THE NRN EDGE OF THE FORECAST AREA. A COLD AND VERY DRY AIR MASS HAS SETTLED OVER THE REGION. EVAPORATIVE COOLING WILL PRODUCE FREEZING TEMPERATURES AT AND JUST ABOVE THE SURFACE OVER NRN ZONES AT THE ONSET OF PRECIP THIS EVENING. FREEZING TEMPERATURES IN THE ADVISORY AREA...FROM CLEVELAND TO COLUMBUS...WILL BE DEEP ENOUGH FOR A MIXTURE OF SNOW AND SLEET EARLY TONIGHT. THE TIER FURTHER S WILL SEE RAIN AND SLEET MIXED WITH SNOW AND FREEZING RAIN BUT LITTLE OR NO ACCUMULATION OF WINTER PRECIP IS EXPECTED. WET BULB ZERO TEMPS WILL HOVER IN A LAYER ABOVE THE SURFACE INTO CENTRAL ZONES RESULTING IN THE POSSIBILITY OF A RAIN AND SLEET MIXTURE INTO THE I-20 CORRIDOR BUT SLEET WILL MELT RAPIDLY ON CONTACT WITH THE GROUND. THE ADVECTION OF WARMER AIR AROUND 850 MB AND COOLING OF LOWER LEVELS NEAR THE SURFACE AFTER THE ONSET OF RAIN HAS REQUIRED A VARIED PATTERN OF WEATHER TYPES FROM NORTH TO SOUTH FOR TONIGHT. DIFFERENCES IN FORECAST TEMPERATURES...ESPECIALLY AT THE SURFACE...OF ONLY A DEGREE OR TWO WILL MEAN A POTENTIAL CHANGE IN THE WEATHER TYPE FOR MANY NRN AND CENTRAL ZONES. PRECIP HAS DEVELOPED OVER WRN ZONES THIS AFTERNOON WITH RAIN/SLEET MIXTURE ALREADY REPORTED OVER NE LA. TEMPERATURES WILL BEGIN TO INCREASE BY MIDNIGHT OVER MOST AREAS WHEN THE AIR COLUMN BEGINS TO MOISTEN AND EVAPORATIVE COOLING IS SHUT DOWN. WE WILL MAINTAIN A CHANCE OF A RAIN/SLEET MIX FOR AREAS ALONG AND N OF THE HIGHWAY 82 CORRIDOR AFTER MIDNIGHT BUT MOST OTHER AREAS WILL SEE PRECIP TURN TO ALL RAIN BY OR SHORTLY AFTER MIDNIGHT. RAIN WILL BE WIDESPREAD OVER THE FORECAST AREA BY SUNRISE THURSDAY AND TEMPERATURES WILL BE ABOVE FREEZING ACROSS THE REGION. THE SURFACE TROUGH LIFTS INTO SRN ZONES BY THURSDAY AFTERNOON... POSITIONING THE ASSOCIATED WARM FRONT IN SE MS BY 18Z. WILL MAINTAIN CHANCE OF THUNDERSTORMS THOSE AREAS TOMORROW AFTERNOON BUT THE TRACK LOOKS TOO FAR S TO SUPPORT ENOUGH INSTABILITY FOR SEVERE CONVECTION. UNDERCUT MOS HIGH TEMPS SLIGHTLY FOR TOMORROW CONSIDERING RAIN SHIELD AND SRN EXTENT OF SURFACE TROUGH. THE BOUNDARY IS EXPECTED TO MOVE THROUGH THE AREA BY THURSDAY EVENING. BEHIND THIS SYSTEM...SFC HIGH PRESSURE OVER THE GREAT PLAINS STATES WILL BEGIN TO MOVE INTO THE AREA FROM THE NORTHWEST. ISENTROPIC ANALYSIS AT THE 285-295K LEVEL AND REMAINING MOISTURE (PWATS AROUND 0.5-0.8 INCH) SHOW A SLIGHT CHANCE FOR SHOWERS FOR FRIDAY...MAINLY IN THE MORNING. WENT AHEAD AND STAYED WITH GUI FOR THU NIGHT INTO SATURDAY MORNING. ANY SHOWERS WILL NOT LAST LONG AS THE ECMWF AND GFS BOTH SHOW HIGH PRESSURE AND NORTHWEST FLOW ALOFT TAKING OVER THE REGION TO START CLEARING OVER THE ARKLAMISS BY SATURDAY AFTERNOON. THE ARCTIC AIRMASS THAT IS MOVING INTO THE REGION WILL COMBINE WITH CLEAR SKIES TO ALLOW LOW TEMPERATURES TO AGAIN DIP DOWN INTO THE 20S FOR THE END OF THE WEEKEND INTO THE BEGINNING OF THE WORK WEEK. THE MAIN CHANGES MADE TO TEMPERATURES WERE TO LOWER JUST A BIT ON FRIDAY NIGHT. SKIES WILL BE CLEARING AS HIGH PRESSURE MOVES IN...AND 925MB TEMPS LOOK TO RANGE FROM 0C TO -8C FOR THIS TIME PERIOD. DECIDED TO JUST BUMP TEMPERATURES DOWN A DEGREE OR TWO FOR THIS TIME PERIOD. FOR THE EXTENDED PORTION OF THE FORECAST (PAST SATURDAY NIGHT)...NO MAJOR CHANGES WERE NECESSARY. THE PREVIOUS LONG TERM DISCUSSION FOLLOWS. /14/ PREVIOUS LONG TERM DISCUSSION...THE DOMINANT HUDSON BAY LOW PATTERN WILL CONTINUE TO BRING SEVERAL COLD EPISODES FOR THE NEXT ONE TO TWO WEEKS IN MOSTLY DRY NORTHWEST FLOW. WITHOUT MUCH TO FOCUS ON PRECIP-WISE...THE PRIMARY FORECAST QUESTIONS CONCERN THE INTENSITY OF COLD AS THE FORECAST AREA WILL EXIST ON THE SRN EDGE OF THE POLAR VORTEX. AT THIS TIME...IT LOOKS AS IF THE CENTER OF COLD AIR ANOMALIES WILL STAY NORTH OF THE REGION...BUT THE NEXT FEW SURGES OF COLD AIR WILL BE SHALLOW AND OF TRUE ARCTIC ORIGINS FROM NEAR THE NORTH POLE. GIVEN RECENT GFS PERFORMANCES WITH SUCH AIRMASSES...HAVE OPTED TO TREND TOWARD COOLER GFS MEAN ENSEMBLE GUIDANCE AND CUT MEX GUIDANCE FROM FRIDAY NIGHT ONWARD (AT LEAST FOR PORTIONS OF THE FORECAST AREA). /EC/ && .AVIATION...WIDESPREAD WINTER PRECIP WILL DEVELOP ACROSS THE REGION THIS EVENING ALONG AND NORTH OF INTERSTATE 20 WITH THE BEST COVERAGE OVER AREAS ALONG AND NORTH OF HIGHWAY 82. HAVE RECEIVED REPORTS OF SLEET OVER NE LA AND TVR THIS AFTERNOON AS INITIAL PRECIP AREA MOVES IN. CLOUD HEIGHTS WILL GRADUALLY DROP AS PRECIP INCREASES IN COVERAGE AND INTENSITY TONIGHT WITH MVFR CONDITIONS MANY LOCATIONS BY MIDNIGHT AND IFR CONDITIONS BY SUNRISE. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 36 45 36 51 / 98 97 25 16 MERIDIAN 35 49 37 53 / 100 96 33 16 VICKSBURG 36 42 37 50 / 96 89 25 17 HATTIESBURG 40 53 39 57 / 100 99 29 16 NATCHEZ 38 46 34 53 / 98 91 22 16 GREENVILLE 32 38 33 43 / 99 95 39 18 GREENWOOD 30 39 34 46 / 100 97 37 18 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR MSZ018-019- 025>034. LA...NONE. AR...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR ARZ074-075. && $$ 03/14 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1236 PM EST THU FEB 1 2007 .AVIATION /18Z-18Z/... VFR CONDS UNDER MOSTLY HIGH CIRRUS EXPECTED THIS AFTERNOON AND EVENING. CLD BASES ARND 2500 FEET WILL SPREAD INTO KELM AFTER 06Z WITH LIGHT SNOW EXPECTED. MVFR CIGS GRADUALLY WORK THEIR WAY WEST AND MOVE INTO KITH/KBGM AT 08Z AND KSYR/KRME BY 09Z. SNOW OVERSPREADS TERMINALS AFTER MIDNIGHT. OCNL VSBY RESTRICTIONS TO LIFR EXPECTED OVER SRN TERMINALS BTWN 10Z-14Z OVER CENTRAL THREE TAF SITES AND BTWN 14Z-18Z AT KAVP. GENERAL LIGHT SNOW WITH MVFR CONDS AT KSYR/KRME AFTER 12Z. WINDS FROM SOUTHWEST AT 10-15KTS THIS AFTERNOON BCMG SOUTHEAST AFTER MIDNIGHT. GENERALLY LIGHT SPEEDS ARND 5KTS ALL SITES. && PREV DISCUSSION... /ISSUED 903 AM EST THU FEB 1 2007/ UPDATE... SOME MID LVL DRYING ACRS THE BGM FCST AREA TAD, WITH DEEPER MSTR ARRIVING FROM THE SOUTH TWD EVNG. SAT PIX SHOW SIG BREAKS IN THE MID/UPR DECK TO OUR W AND SW, AND WILL BE MORE OPTIMISTIC WITH SKY COVER (LEANING TWD RUC SKY GRIDS WITH PC TO MC SKIES). SOME --SHSN ACRS ERN ZONES, BUT THESE ARE DSPTNG AND XPCT TREND TO CONTINUE, SO A DRY FCST FOR THIS AFTN. PREV DISCUSSION... /ISSUED 305 AM EST THU FEB 1 2007/ SHORT TERM /TODAY THROUGH FRIDAY NIGHT/... HIGH PRESSURE IS SLIDING OFF THE EAST COAST THIS MORNING. RISING MOTION TO THE WEST IS IMPORTING A MID DECK OF CLOUD COVER, AND MAY PRODUCE A FEW STRAY SNOW SHOWERS TODAY. MEANWHILE A WAVE MOVING THROUGH THE GULF STATES WILL CAUSE A STRONGER CYCLONE TO FORM TONIGHT. THIS STORM WILL QUICKLY MOVE UP THE ATLANTIC SEABOARD. MODEL TRENDS REMAIN SIMILAR TO WHAT WE SAW PVS 24H...THAT SYSTEM WILL REMAIN FAR ENOUGH OUT TO SEA TO KEEP SIG SNOW WELL EAST OF OUR FA. HOWEVER SYSTEM WILL BE RESPONSIBLE FOR LIGHT SNOW OVER MUCH OF THE REGION, WITH POSSIBILITY OF AN INCH OR TWO ACCUMULATION OVER SOUTHEASTERN ZONES. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER ENTIRE REGION, FIRST SPREADING INTO NE PA LATE TONIGHT AND THEN OVER REMAINDER OF REGION BETWEEN 11Z-15Z. COLD AIR WILL POUR DOWN FROM CANADA BEHIND THE CYCLONE AS TROF DEEPENS INTO THE OHIO VALLEY. WITH THE AXIS UPSTREAM, WE WILL BE IN A COLD SOUTHWESTERLY FLOW, WHICH SHOULD KEEP LAKE EFFECT MAINLY NORTH OF THE REGION. HAVE ADJUSTED GRIDS TO REFLECT PERIPHERY OF POSSIBLE SNOW BANDS OVER NORTHERN FINGER LAKES, AND NORTHWESTERN PORTION OF MOHAWK VALLEY. DJP LONG TERM /SATURDAY THROUGH WEDNESDAY/... HAVE PRETTY MUCH FOLLOWED HPC GUIDANCE THRU EXTENDED. STILL LOOKING AT BLO NORMAL TEMPS TO CONTINUE DURG THE PERIOD. HIGHS EXPECTED TO BE IN THE TEENS AND LOWS IN THE SINGLE DIGITS AND/OR BLO ZERO. WK ISENTROPIC LIFT EXPECTED ON SATURDAY WITH SCTD SNOW SHOWERS. CLIPPER COMES THRU ON SAT NIGHT INTO SUN WITH LAKE EFFECT KICKING IN BEHIND IT. BOTH 06Z/12Z GFS KICKS OUT SFC LOW INTO CNTRL PLAIN ON MONDAY AND TRACKS IT ALONG MASON-DIXON LINE MON AND MON NIGHT. EURO KEEPS LOW FURTHER SOUTH WITH CANADIAN FASTER AND FURTHER NORTH. STILL A LOT OF UNCERTAINTY WITH THIS SYSTEM...ALTHOUGH 12Z GFS SLIGHTLY FURTHER SOUTH WITH QPF AMTS THAN THE 06Z RUN. THIS WOULD KEEP MOST OF SNOW SOUTH OF FA. HAVE OPTED TO GO WITH MORE LES DURING THIS PERIOD THAN SYNOPTIC SCALE SNOWS BUT THIS WILL NEED TO BE WATCHED. PB && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. && $$ AVIATION...PB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1236 PM EST THU FEB 1 2007 .AVIATION /18Z-18Z/... VFR CONDS UNDER MOSTLY HIGH CIRRUS EXPECTED THIS AFTERNOON AND EVENING. CLD BASES ARND 2500 FEET WILL SPREAD INTO KELM AFTER 06Z WITH LIGHT SNOW EXPECTED. MVFR CIGS GRADUALLY WORK THEIR WAY WEST AND MOVE INTO KITH/KBGM AT 08Z AND KSYR/KRME BY 09Z. SNOW OVERSPREADS TERMINALS AFTER MIDNIGHT. OCNL VSBY RESTRICTIONS TO LIFR EXPECTED OVER SRN TERMINALS BTWN 10Z-14Z OVER CENTRAL THREE TAF SITES AND BTWN 14Z-18Z AT KAVP. GENERAL LIGHT SNOW WITH MVFR CONDS AT KSYR/KRME AFTER 12Z. WINDS FROM SOUTHWEST AT 10-15KTS THIS AFTERNOON BCMG SOUTHEAST AFTER MIDNIGHT. GENERALLY LIGHT SPEEDS ARND 5KTS ALL SITES. && PREV DISCUSSION... /ISSUED 903 AM EST THU FEB 1 2007/ UPDATE... SOME MID LVL DRYING ACRS THE BGM FCST AREA TAD, WITH DEEPER MSTR ARRIVING FROM THE SOUTH TWD EVNG. SAT PIX SHOW SIG BREAKS IN THE MID/UPR DECK TO OUR W AND SW, AND WILL BE MORE OPTIMISTIC WITH SKY COVER (LEANING TWD RUC SKY GRIDS WITH PC TO MC SKIES). SOME --SHSN ACRS ERN ZONES, BUT THESE ARE DSPTNG AND XPCT TREND TO CONTINUE, SO A DRY FCST FOR THIS AFTN. PREV DISCUSSION... /ISSUED 305 AM EST THU FEB 1 2007/ SHORT TERM /TODAY THROUGH FRIDAY NIGHT/... HIGH PRESSURE IS SLIDING OFF THE EAST COAST THIS MORNING. RISING MOTION TO THE WEST IS IMPORTING A MID DECK OF CLOUD COVER, AND MAY PRODUCE A FEW STRAY SNOW SHOWERS TODAY. MEANWHILE A WAVE MOVING THROUGH THE GULF STATES WILL CAUSE A STRONGER CYCLONE TO FORM TONIGHT. THIS STORM WILL QUICKLY MOVE UP THE ATLANTIC SEABOARD. MODEL TRENDS REMAIN SIMILAR TO WHAT WE SAW PVS 24H...THAT SYSTEM WILL REMAIN FAR ENOUGH OUT TO SEA TO KEEP SIG SNOW WELL EAST OF OUR FA. HOWEVER SYSTEM WILL BE RESPONSIBLE FOR LIGHT SNOW OVER MUCH OF THE REGION, WITH POSSIBILITY OF AN INCH OR TWO ACCUMULATION OVER SOUTHEASTERN ZONES. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER ENTIRE REGION, FIRST SPREADING INTO NE PA LATE TONIGHT AND THEN OVER REMAINDER OF REGION BETWEEN 11Z-15Z. COLD AIR WILL POUR DOWN FROM CANADA BEHIND THE CYCLONE AS TROF DEEPENS INTO THE OHIO VALLEY. WITH THE AXIS UPSTREAM, WE WILL BE IN A COLD SOUTHWESTERLY FLOW, WHICH SHOULD KEEP LAKE EFFECT MAINLY NORTH OF THE REGION. HAVE ADJUSTED GRIDS TO REFLECT PERIPHERY OF POSSIBLE SNOW BANDS OVER NORTHERN FINGER LAKES, AND NORTHWESTERN PORTION OF MOHAWK VALLEY. DJP LONG TERM /SATURDAY THROUGH WEDNESDAY/... HAVE PRETTY MUCH FOLLOWED HPC GUIDANCE THRU EXTENDED. STILL LOOKING AT BLO NORMAL TEMPS TO CONTINUE DURG THE PERIOD. HIGHS EXPECTED TO BE IN THE TEENS AND LOWS IN THE SINGLE DIGITS AND/OR BLO ZERO. WK ISENTROPIC LIFT EXPECTED ON SATURDAY WITH SCTD SNOW SHOWERS. CLIPPER COMES THRU ON SAT NIGHT INTO SUN WITH LAKE EFFECT KICKING IN BEHIND IT. BOTH 06Z/12Z GFS KICKS OUT SFC LOW INTO CNTRL PLAIN ON MONDAY AND TRACKS IT ALONG MASON-DIXON LINE MON AND MON NIGHT. EURO KEEPS LOW FURTHER SOUTH WITH CANADIAN FASTER AND FURTHER NORTH. STILL A LOT OF UNCERTAINTY WITH THIS SYSTEM...ALTHOUGH 12Z GFS SLIGHTLY FURTHER SOUTH WITH QPF AMTS THAN THE 06Z RUN. THIS WOULD KEEP MOST OF SNOW SOUTH OF FA. HAVE OPTED TO GO WITH MORE LES DURING THIS PERIOD THAN SYNOPTIC SCALE SNOWS BUT THIS WILL NEED TO BE WATCHED. PB && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. && $$ AVIATION...PB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1118 AM EST THU FEB 1 2007 .UPDATE... PARTLY SUNNY SKIES ACRS THE RGN...SKY GRIDS AND ZONES UPDATED ACCORDINGLY. && .PREV DISCUSSION... /ISSUED 903 AM EST THU FEB 1 2007/ UPDATE... SOME MID LVL DRYING ACRS THE BGM FCST AREA TDA, WITH DEEPER MSTR ARRIVING FROM THE SOUTH TWDS EVNG. SAT PIX SHOW SIG BREAKS IN THE MID/UPR DECK TO OUR W AND SW, AND WILL BE MORE OPTIMISTIC WITH SKY COVER (LEANING TWDS RUC SKY GRIDS WITH PC TO MC SKIES). SOME --SHSN ACRS ERN ZONES, BUT THESE ARE DSPTNG AND XPCT TREND TO CONTINUE, SO A DRY FCST FOR THIS AFTN. PREV DISCUSSION... /ISSUED 618 AM EST THU FEB 1 2007/ AVIATION /12Z-12Z/... BROKEN MID DECK THIS MORNING WILL PERSIST THROUGH THE DAY. WINDS WILL BE LIGHT OUT OF THE SOUTH THIS MORNING, AND WILL INCREASE TO 8-12 KTS OUT OF THE SOUTHWEST THIS AFTERNOON. A STRAY LIGHT SNOW SHOWER IS POSSIBLE BUT VFR CONDITIONS ARE FORECAST. LIGHT SNOW WILL OVERSPREAD EARLY FRIDAY MORNING. EXPECT CIGS TO LOWER TO MVFR AROUND 06Z WITH VIS FALLING TO 2-4SM IN LIGHT SNOW MAINLY FROM ITH-BGM SOUTHWARD TO ELM-AVP. DJP PREV DISCUSSION... /ISSUED 305 AM EST THU FEB 1 2007/ SHORT TERM /TODAY THROUGH FRIDAY NIGHT/... HIGH PRESSURE IS SLIDING OFF THE EAST COAST THIS MORNING. RISING MOTION TO THE WEST IS IMPORTING A MID DECK OF CLOUD COVER, AND MAY PRODUCE A FEW STRAY SNOW SHOWERS TODAY. MEANWHILE A WAVE MOVING THROUGH THE GULF STATES WILL CAUSE A STRONGER CYCLONE TO FORM TONIGHT. THIS STORM WILL QUICKLY MOVE UP THE ATLANTIC SEABOARD. MODEL TRENDS REMAIN SIMILAR TO WHAT WE SAW PVS 24H...THAT SYSTEM WILL REMAIN FAR ENOUGH OUT TO SEA TO KEEP SIG SNOW WELL EAST OF OUR FA. HOWEVER SYSTEM WILL BE RESPONSIBLE FOR LIGHT SNOW OVER MUCH OF THE REGION, WITH POSSIBILITY OF AN INCH OR TWO ACCUMULATION OVER SOUTHEASTERN ZONES. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER ENTIRE REGION, FIRST SPREADING INTO NE PA LATE TONIGHT AND THEN OVER REMAINDER OF REGION BETWEEN 11Z-15Z. COLD AIR WILL POUR DOWN FROM CANADA BEHIND THE CYCLONE AS TROF DEEPENS INTO THE OHIO VALLEY. WITH THE AXIS UPSTREAM, WE WILL BE IN A COLD SOUTHWESTERLY FLOW, WHICH SHOULD KEEP LAKE EFFECT MAINLY NORTH OF THE REGION. HAVE ADJUSTED GRIDS TO REFLECT PERIPHERY OF POSSIBLE SNOW BANDS OVER NORTHERN FINGER LAKES, AND NORTHWESTERN PORTION OF MOHAWK VALLEY. DJP LONG TERM /SATURDAY THROUGH WEDNESDAY/... HAVE PRETTY MUCH FOLLOWED HPC GUIDANCE THRU EXTENDED. STILL LOOKING AT BLO NORMAL TEMPS TO CONTINUE DURG THE PERIOD. HIGHS EXPECTED TO BE IN THE TEENS AND LOWS IN THE SINGLE DIGITS AND/OR BLO ZERO. WK ISENTROPIC LIFT EXPECTED ON SATURDAY WITH SCTD SNOW SHOWERS. CLIPPER COMES THRU ON SAT NIGHT INTO SUN WITH LAKE EFFECT KICKING IN BEHIND IT. BOTH 06Z/12Z GFS KICKS OUT SFC LOW INTO CNTRL PLAIN ON MONDAY AND TRACKS IT ALONG MASON-DIXON LINE MON AND MON NIGHT. EURO KEEPS LOW FURTHER SOUTH WITH CANADIAN FASTER AND FURTHER NORTH. STILL A LOT OF UNCERTAINTY WITH THIS SYSTEM...ALTHOUGH 12Z GFS SLIGHTLY FURTHER SOUTH WITH QPF AMTS THAN THE 06Z RUN. THIS WOULD KEEP MOST OF SNOW SOUTH OF FA. HAVE OPTED TO GO WITH MORE LES DURING THIS PERIOD THAN SYNOPTIC SCALE SNOWS BUT THIS WILL NEED TO BE WATCHED. PB AVIATION /08Z-06Z/... VERY QUIET TODAY WITH JUST A FEW FLURRIES OR LIGHT SNOW SHOWERS EXPECTED. THESE WILL BE WIDELY SCATTERED, SO DID NOT INCLUDE IN TERMINAL FORECASTS. MID DECK WILL LOWER TO A VFR STRATOCU DECK LATER TODAY. DJP && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 903 AM EST THU FEB 1 2007 .UPDATE... SOME MID LVL DRYING ACRS THE BGM FCST AREA TDA, WITH DEEPER MSTR ARRIVING FROM THE SOUTH TWDS EVNG. SAT PIX SHOW SIG BREAKS IN THE MID/UPR DECK TO OUR W AND SW, AND WILL BE MORE OPTIMISTIC WITH SKY COVER (LEANING TWDS RUC SKY GRIDS WITH PC TO MC SKIES). SOME --SHSN ACRS ERN ZONES, BUT THESE ARE DSPTNG AND XPCT TREND TO CONTINUE, SO A DRY FCST FOR THIS AFTN. && .PREV DISCUSSION... /ISSUED 618 AM EST THU FEB 1 2007/ AVIATION /12Z-12Z/... BROKEN MID DECK THIS MORNING WILL PERSIST THROUGH THE DAY. WINDS WILL BE LIGHT OUT OF THE SOUTH THIS MORNING, AND WILL INCREASE TO 8-12 KTS OUT OF THE SOUTHWEST THIS AFTERNOON. A STRAY LIGHT SNOW SHOWER IS POSSIBLE BUT VFR CONDITIONS ARE FORECAST. LIGHT SNOW WILL OVERSPREAD EARLY FRIDAY MORNING. EXPECT CIGS TO LOWER TO MVFR AROUND 06Z WITH VIS FALLING TO 2-4SM IN LIGHT SNOW MAINLY FROM ITH-BGM SOUTHWARD TO ELM-AVP. DJP PREV DISCUSSION... /ISSUED 305 AM EST THU FEB 1 2007/ SHORT TERM /TODAY THROUGH FRIDAY NIGHT/... HIGH PRESSURE IS SLIDING OFF THE EAST COAST THIS MORNING. RISING MOTION TO THE WEST IS IMPORTING A MID DECK OF CLOUD COVER, AND MAY PRODUCE A FEW STRAY SNOW SHOWERS TODAY. MEANWHILE A WAVE MOVING THROUGH THE GULF STATES WILL CAUSE A STRONGER CYCLONE TO FORM TONIGHT. THIS STORM WILL QUICKLY MOVE UP THE ATLANTIC SEABOARD. MODEL TRENDS REMAIN SIMILAR TO WHAT WE SAW PVS 24H...THAT SYSTEM WILL REMAIN FAR ENOUGH OUT TO SEA TO KEEP SIG SNOW WELL EAST OF OUR FA. HOWEVER SYSTEM WILL BE RESPONSIBLE FOR LIGHT SNOW OVER MUCH OF THE REGION, WITH POSSIBILITY OF AN INCH OR TWO ACCUMULATION OVER SOUTHEASTERN ZONES. WILL KEEP LIKELY POPS FOR LIGHT SNOW OVER ENTIRE REGION, FIRST SPREADING INTO NE PA LATE TONIGHT AND THEN OVER REMAINDER OF REGION BETWEEN 11Z-15Z. COLD AIR WILL POUR DOWN FROM CANADA BEHIND THE CYCLONE AS TROF DEEPENS INTO THE OHIO VALLEY. WITH THE AXIS UPSTREAM, WE WILL BE IN A COLD SOUTHWESTERLY FLOW, WHICH SHOULD KEEP LAKE EFFECT MAINLY NORTH OF THE REGION. HAVE ADJUSTED GRIDS TO REFLECT PERIPHERY OF POSSIBLE SNOW BANDS OVER NORTHERN FINGER LAKES, AND NORTHWESTERN PORTION OF MOHAWK VALLEY. DJP LONG TERM /SATURDAY THROUGH WEDNESDAY/... HAVE PRETTY MUCH FOLLOWED HPC GUIDANCE THRU EXTENDED. STILL LOOKING AT BLO NORMAL TEMPS TO CONTINUE DURG THE PERIOD. HIGHS EXPECTED TO BE IN THE TEENS AND LOWS IN THE SINGLE DIGITS AND/OR BLO ZERO. WK ISENTROPIC LIFT EXPECTED ON SATURDAY WITH SCTD SNOW SHOWERS. CLIPPER COMES THRU ON SAT NIGHT INTO SUN WITH LAKE EFFECT KICKING IN BEHIND IT. BOTH 06Z/12Z GFS KICKS OUT SFC LOW INTO CNTRL PLAIN ON MONDAY AND TRACKS IT ALONG MASON-DIXON LINE MON AND MON NIGHT. EURO KEEPS LOW FURTHER SOUTH WITH CANADIAN FASTER AND FURTHER NORTH. STILL A LOT OF UNCERTAINTY WITH THIS SYSTEM...ALTHOUGH 12Z GFS SLIGHTLY FURTHER SOUTH WITH QPF AMTS THAN THE 06Z RUN. THIS WOULD KEEP MOST OF SNOW SOUTH OF FA. HAVE OPTED TO GO WITH MORE LES DURING THIS PERIOD THAN SYNOPTIC SCALE SNOWS BUT THIS WILL NEED TO BE WATCHED. PB AVIATION /08Z-06Z/... VERY QUIET TODAY WITH JUST A FEW FLURRIES OR LIGHT SNOW SHOWERS EXPECTED. THESE WILL BE WIDELY SCATTERED, SO DID NOT INCLUDE IN TERMINAL FORECASTS. MID DECK WILL LOWER TO A VFR STRATOCU DECK LATER TODAY. DJP && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 215 PM EST THU FEB 1 2007 .SHORT TERM /TONIGHT THROUGH FRIDAY/... TONIGHT...SATELLITE IMAGERY SHOWS A SERIES OF WAVES EMBEDDED IN THE LONG EXTENSION OF THE 150KT SUBTROPICAL JET...EXTENDING FROM THE MEXICAN PLATEAU INTO THE MID-ATLANTIC REGION. THE FIRST S/W DISTURBANCE IS CURRENTLY MOVING THROUGH THE FORECAST AREA...AS THE HEAVIEST PRECIPITATION SHIFTS TO THE EASTERN CWA. THERE WILL BE A LULL IN PRECIPITATION ACROSS CENTRAL NC THIS AFTERNOON AND EARLY EVENING...UNTIL THE SECOND MORE ROBUST UPPER WAVE(CURRENTLY ROUNDING BASE OF THE LONG WAVE TROUGH OVER TEXAS)APPROACHES THE AREA BETWEEN 06Z TO 12Z. PRECIP WILL FILL BACK INTO THE AREA AS FORCING ALOFT FROM LF EXIT REGION AND POSITIVE VORTICITY ADVECTION SPREADS FROM SW TO NE OVER THE AREA. THE LATEST RUC AND MESONAM SOUNDINGS AND SFC TW SUPPORT ALL RAIN ACROSS THE ADVISORY AREA BY 00Z...WITH FURTHER SUPPORT FROM PARTIAL THICKNESS NOMOGRAM AND CONSENSUS OF THE VARIOUS P-TYPE ALGORITHMS(RAMER...BOURGOUIN...REVISED NCEP). AS A RESULT CONFIDENCE IS HIGH THAT THE THREAT OF FREEZING RAIN WILL BE OVER BY 6PM(IF NOT EARLIER)...AND THUS WILL NOT BE EXTENDED. WILL ADJUST GRIDS TO SHOW RAIN INCREASING LATE IN THE EVENING... AND THEN GRADUALLY TAPERING OFF INTO DRIZZLE AS MID-LEVELS BEGIN TO DRY OUT BY AROUND DAYBREAK. TEMPERATURES OVERNIGHT WILL BE STEADY OR SLIGHTLY RISING WITH ABSENCE OF CAA AND AS THE RAIN FALLS INTO THE 3 TO 5C WARM NOSE. TEMPERATURES OVERNIGHT IN THE LOWER TO MID 30S. FRIDAY...A CHANCE OF RAIN IN THE MORNING...THEN RAIN ENDING WEST TO EAST. CENTRAL NC REMAINS IN WARM SECTOR AND LOW-LEVELS REMAIN SATURATED UNTIL FROPA WHICH OCCURRS AROUND 00Z. HIGHS 45 TO 50. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... FRIDAY NIGHT THROUGH SUNDAY..DRY SURGE COMMENCES FRIDAY NIGHT WITH CLEARING SKIES. NAM/GFS REMAIN A BIT AT ODDS CONCERNING THE DEEPENING TROF OVER THE SOUTHWESTERN CONUS...WITH THE NAM BEING CLOSER TO CONSENSUS WITH THE UKMET/ECMWF...HAVING A MORE AMPLIFIED UPPER TROF AND DELAYING THE COLD AIR PUSH INTO THE EASTERN CONUS. THE RESULTING MOS MAX TEMPS ARE THUS A BIT IN QUESTION...BUT WILL TOP OUT MAINLY IN THE MID AND UPPER 40S REGARDLESS. THE SURFACE HIGH AND THE UPPER TROF EDGE EAST ON SUNDAY. NAM IS SLOWER WITH THIS PROGRESSION AS IT DRIVES ARTIC AIR DEEPER INTO THE MIDWEST...CONTINUING TO AMPLIFY THE UPPER TROF AND DELAY THE COLDEST AIR. WILL CONTINUE MOSTLY CLEAR SKIES WITH HIGHS STRUGGLING INTO THE 40 TO 45 DEGREE RANGE. THE FLOW ALOFT IS DOMINATED BY A BROAD LARGE SCALE TROUGH OVER THE EASTERN TWO-THIRDS OF THE CONUS WITH A TROUGH AXIS THAT STEEPENS OVER THE APPALACHIANS AROUND TUE NIGHT...THEN FLATTENS AS THE TROUGH LOSES AMPLITUDE BY THU. SURFACE FEATURES SHOW WEAK HIGH PRESSURE DRIFTING ACROSS THE AREA SUN NGT AND MON AHEAD OF A COLD FRONT MON NIGHT THAT USHERS ANOTHER ARCTIC AIRMASS SOUTHEASTWARD OUT OF THE NORTHERN PLAINS. THE OVERNIGHT GFS SHOWS A WEAK LOW FORMATION IN THE LEE OF THE APPALACHIANS WITH THE COLD FRONT LATE MON... SUGGESTING SOME MOISTURE CONVERGENCE IN LOWER TO MID LEVELS. OTHER MODELS DO NOT RESOLVE THIS FEATURE. THE SURFACE LAYER IS EXPECTED TO BE VERY DRY WITH DEW POINTS OF 10-15 DEGREES AND CHANCES OF PRECIPITATION HITTING THE GROUND REMAIN LESS THAN 15 PERCENT IN THE RAH CWA. TEMPERATURES DROP TO BETWEEN 10 AND 20 DEGREES BELOW NORMAL FOLLOWING THE ARCTIC COLD FRONT FOR TUE AND WED MODERATING BUT STILL BELOW NORMAL ON THU. && .AVIATION /18Z-18Z/... A COOL SATURATED AIRMASS IN THE WAKE OF LOW PRESSURE ALONG THE NC COAST WILL MAINTAIN IFR AND LIFR CONDITIONS ACROSS CENTRAL NC THROUGH TONIGHT AND FRI MORNING. WIDESPREAD RAIN...WITH SOME FREEZING RAIN POSSIBLE AT KINT AND KGSO EARLY THIS AFTERNOON...WILL TAPER TO DRIZZLE EARLY THIS EVENING. MORE AREAS OF RAIN WILL LIKELY CROSS CENTRAL NC IN THE PREDAWN HOURS FRI MORNING...ENDING SHORTLY AFTERNOON DAYBREAK. CONDITIONS WILL GRADUALLY IMPROVE TO ABOVE IFR FRI AFTERNOON AS A SURGE OF DRIER AIR PUSHES IN FROM THE WEST. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR NCZ007-008-021>025-038>040. && $$ SHORT TERM...CBL LONG TERM...RFG/MLM AVIATION...RFG nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 215 PM EST THU FEB 1 2007 .SHORT TERM /TONIGHT THROUGH FRIDAY/... TONIGHT...SATELLITE IMAGERY SHOWS A SERIES OF WAVES EMBEDDED IN THE LONG EXTENSION OF THE 150KT SUBTROPICAL JET...EXTENDING FROM THE MEXICAN PLATEAU INTO THE MID-ATLANTIC REGION. THE FIRST S/W DISTURBANCE IS CURRENTLY MOVING THROUGH THE FORECAST AREA...AS THE HEAVIEST PRECIPITATION SHIFTS TO THE EASTERN CWA. THERE WILL BE A LULL IN PRECIPITATION ACROSS CENTRAL NC THIS AFTERNOON AND EARLY EVENING...UNTIL THE SECOND MORE ROBUST UPPER WAVE(CURRENTLY ROUNDING BASE OF THE LONG WAVE TROUGH OVER TEXAS)APPROACHES THE AREA BETWEEN 06Z TO 12Z. PRECIP WILL FILL BACK INTO THE AREA AS FORCING ALOFT FROM LF EXIT REGION AND POSITIVE VORTICITY ADVECTION SPREADS FROM SW TO NE OVER THE AREA. THE LATEST RUC AND MESONAM SOUNDINGS AND SFC TW SUPPORT ALL RAIN ACROSS THE ADVISORY AREA BY 00Z...WITH FURTHER SUPPORT FROM PARTIAL THICKNESS NOMOGRAM AND CONSENSUS OF THE VARIOUS P-TYPE ALGORITHMS(RAMER...BOURGOUIN...REVISED NCEP). AS A RESULT CONFIDENCE IS HIGH THAT THE THREAT OF FREEZING RAIN WILL BE OVER BY 6PM(IF NOT EARLIER)...AND THUS WILL NOT BE EXTENDED. WILL ADJUST GRIDS TO SHOW RAIN INCREASING LATE IN THE EVENING... AND THEN GRADUALLY TAPERING OFF INTO DRIZZLE AS MID-LEVELS BEGIN TO DRY OUT BY AROUND DAYBREAK. TEMPERATURES OVERNIGHT WILL BE STEADY OR SLIGHTLY RISING WITH ABSENCE OF CAA AND AS THE RAIN FALLS INTO THE 3 TO 5C WARM NOSE. TEMPERATURES OVERNIGHT IN THE LOWER TO MID 30S. FRIDAY...A CHANCE OF RAIN IN THE MORNING...THEN RAIN ENDING WEST TO EAST. CENTRAL NC REMAINS IN WARM SECTOR AND LOW-LEVELS REMAIN SATURATED UNTIL FROPA WHICH OCCURRS AROUND 00Z. HIGHS 45 TO 50. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... FRIDAY NIGHT THROUGH SUNDAY..DRY SURGE COMMENCES FRIDAY NIGHT WITH CLEARING SKIES. NAM/GFS REMAIN A BIT AT ODDS CONCERNING THE DEEPENING TROF OVER THE SOUTHWESTERN CONUS...WITH THE NAM BEING CLOSER TO CONSENSUS WITH THE UKMET/ECMWF...HAVING A MORE AMPLIFIED UPPER TROF AND DELAYING THE COLD AIR PUSH INTO THE EASTERN CONUS. THE RESULTING MOS MAX TEMPS ARE THUS A BIT IN QUESTION...BUT WILL TOP OUT MAINLY IN THE MID AND UPPER 40S REGARDLESS. THE SURFACE HIGH AND THE UPPER TROF EDGE EAST ON SUNDAY. NAM IS SLOWER WITH THIS PROGRESSION AS IT DRIVES ARTIC AIR DEEPER INTO THE MIDWEST...CONTINUING TO AMPLIFY THE UPPER TROF AND DELAY THE COLDEST AIR. WILL CONTINUE MOSTLY CLEAR SKIES WITH HIGHS STRUGGLING INTO THE 40 TO 45 DEGREE RANGE. THE FLOW ALOFT IS DOMINATED BY A BROAD LARGE SCALE TROUGH OVER THE EASTERN TWO-THIRDS OF THE CONUS WITH A TROUGH AXIS THAT STEEPENS OVER THE APPALACHIANS AROUND TUE NIGHT...THEN FLATTENS AS THE TROUGH LOSES AMPLITUDE BY THU. SURFACE FEATURES SHOW WEAK HIGH PRESSURE DRIFTING ACROSS THE AREA SUN NGT AND MON AHEAD OF A COLD FRONT MON NIGHT THAT USHERS ANOTHER ARCTIC AIRMASS SOUTHEASTWARD OUT OF THE NORTHERN PLAINS. THE OVERNIGHT GFS SHOWS A WEAK LOW FORMATION IN THE LEE OF THE APPALACHIANS WITH THE COLD FRONT LATE MON... SUGGESTING SOME MOISTURE CONVERGENCE IN LOWER TO MID LEVELS. OTHER MODELS DO NOT RESOLVE THIS FEATURE. THE SURFACE LAYER IS EXPECTED TO BE VERY DRY WITH DEW POINTS OF 10-15 DEGREES AND CHANCES OF PRECIPITATION HITTING THE GROUND REMAIN LESS THAN 15 PERCENT IN THE RAH CWA. TEMPERATURES DROP TO BETWEEN 10 AND 20 DEGREES BELOW NORMAL FOLLOWING THE ARCTIC COLD FRONT FOR TUE AND WED MODERATING BUT STILL BELOW NORMAL ON THU. && .AVIATION /18Z-18Z/... A COOL SATURATED AIRMASS IN THE WAKE OF LOW PRESSURE ALONG THE NC COAST WILL MAINTAIN IFR AND LIFR CONDITIONS ACROSS CENTRAL NC THROUGH TONIGHT AND FRI MORNING. WIDESPREAD RAIN...WITH SOME FREEZING RAIN POSSIBLE AT KINT AND KGSO EARLY THIS AFTERNOON...WILL TAPER TO DRIZZLE EARLY THIS EVENING. MORE AREAS OF RAIN WILL LIKELY CROSS CENTRAL NC IN THE PREDAWN HOURS FRI MORNING...ENDING SHORTLY AFTERNOON DAYBREAK. CONDITIONS WILL GRADUALLY IMPROVE TO ABOVE IFR FRI AFTERNOON AS A SURGE OF DRIER AIR PUSHES IN FROM THE WEST. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR NCZ007-008-021>025-038>040. && $$ SHORT TERM...CBL LONG TERM...RFG/MLM AVIATION...RFG nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1045 AM EST THU FEB 1 2007 .UPDATE... && .SHORT TERM /REST OF TODAY/... THE INITIAL HEAVY BURST OF SNOW HAS RESULTED IN HEAVIEST SNOWFALL TOTALS ACROSS THE SOUTHERN HALF OF CWA...SEEN CLEARLY EARLIER ON THE KRAX RADAR IMAGERY WITH THE BRIGHT BAND REFLECTIVITY EXTENDING OVER THE SOUTHERN SECTOR. REPORTS INDICATE THE HIGHEST AMOUNTS ACROSS THE SOUTHWEST PIEDMONT...STANLY...ANSON...AND MONTGOMERY AND MOORE COUNTIES. 1 TO 1.5 INCHES WAS REPORTED IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN...WHICH PROMPTED RAISING A WINTER WX ADVISORY THROUGH NOON. MEANWHILE ACROSS THE NORTHERN HALF...SNOW AMOUNTS ARE LESS THAN AN INCH WITH THE TRIAD AND COUNTIES ALONG THE VA BORDER REPORTING ONLY A TRACE. CURRENTLY... REAL TIME REPORTS...AIRCRAFT(AMDAR)SOUNDINGS...AND THE MRR-VERTICALLY POINTING RADAR...ARE ALL SHOWING THE ADVERTISED WARMING NOSE ALOFT ADVANCING NORTH WITH THE MELTING LAYER STARTING TO DESCEND DOWN TO THE SURFACE. REPORTS EXTENDING FROM ALBEMARLE...MOORE... FAYETTEVILLE HAVE CHANGED OVER TO SLEET OR FREEZING RAIN. THE LATEST RUC IS MODELING THE THERMAL PROFILE FAIRLY WELL WHEN COMPARED TO THE LATEST AMDAR SOUNDING FROM GSO...WITH IT A LITTLE TOO COOL ALOFT AND SLIGHTLY TOO WARM NEAR THE SURFACE SURFACE. WITH THE MAIN WARM/MOIST AIR CONVEYOR BELT DIRECTED IN A MORE SW TO NE FASHION AND TRANSLATING IN A MORE EASTERLY DIRECTION...RADARS RETURNS HAVE BEEN HARD TO COME BY ACROSS THE TRIAD. IT APPEARS THAT THE PREDICTED SNOWFALL OF 1 TO 2 INCHES WILL NOT BE REALIZED. HOWEVER...PRECIP WILL SPREAD BACK NORTH THIS AFTERNOON AS THE WELL-DEFINED WAVE OVER ALABAMA TRANSLATES NE TOWARDS CENTRAL NC. BY THAT TIME...THE THERMAL PROFILE WILL BE WARMING TO SUPPORT A TRANSITION TO SLEET AND THE ANTICIPATED FREEZING RAIN. THERE IS STILL YET ANOTHER WAVE OVER THE TEXAS AND OKLAHOMA THIS IS PROGGED TO APPROACH THE AREA BETWEEN 00Z TO 06Z. SO BY NO MEANS IS THE TRIAD OUT OF THE WOODS...WITH A QUARTER OF AN INCH ICE STILL VERY POSSIBLE. WILL BE KEEPING ALL WARNINGS AND ADVISORIES UP...BUT LOWER THE SNOWFALL AMOUNTS AND POPS. OTHERWISE...MINOR ADJUSTMENTS TO FORECAST OF P-TYPE AND TIMING OF CHANGEOVER. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... THE FLOW ALOFT IS DOMINATED BY A BROAD LARGE SCALE TROUGH OVER THE EASTERN TWO-THIRDS OF THE CONUS WITH A TROUGH AXIS THAT STEEPENS OVER THE APPALACHIANS AROUND TUE NIGHT...THEN FLATTENS AS THE TROUGH LOSES AMPLITUDE BY THU. SURFACE FEATURES SHOW WEAK HIGH PRESSURE DRIFTING ACROSS THE AREA SUN NGT AND MON AHEAD OF A COLD FRONT MON NIGHT THAT USHERS ANOTHER ARCTIC AIRMASS SOUTHEASTWARD OUT OF THE NORTHERN PLAINS. THE OVERNIGHT GFS SHOWS A WEAK LOW FORMATION IN THE LEE OF THE APPALACHIANS WITH THE COLD FRONT LATE MON... SUGGESTING SOME MOISTURE CONVERGENCE IN LOWER TO MID LEVELS. OTHER MODELS DO NOT RESOLVE THIS FEATURE. THE SURFACE LAYER IS EXPECTED TO BE VERY DRY WITH DEW POINTS OF 10-15 DEGREES AND CHANCES OF PRECIPITATION HITTING THE GROUND REMAIN LESS THAN 15 PERCENT IN THE RAH CWA. TEMPERATURES DROP TO BETWEEN 10 AND 20 DEGREES BELOW NORMAL FOLLOWING THE ARCTIC COLD FRONT FOR TUE AND WED MODERATING BUT STILL BELOW NORMAL ON THU. && .PREV DISCUSSION... /ISSUED 312 AM EST THU FEB 1 2007/ SHORT TERM /TODAY THROUGH SATURDAY NIGHT/... TODAY THROUGH FRIDAY... INTERESTING AND SOMEWHAT TRICKY FORECAST FOR THE NEXT 24 HOURS OVER A LARGE PORTION OF CENTRAL NORTH CAROLINA. MID/HIGH LEVEL CLOUDS SPREADING INTO AREA RESULTING IN TEMPERATURES BOUNCING AROUND SHOWING RISES WHICH MAKES FORECAST ALL THE MORE TRICKY. BUT DEWPOINTS ARE QUITE LOW...STILL SINGLE DIGITS IN NORTHWEST BUT A SLIGHT RISE OVER SOUTH/SOUTHWEST SECTIONS. HOWEVER EXPECT TEMPERATURES TO FALL ONCE PRECIP STARTS. ONSET TIMING AND QPF AMOUNTS ARE THE KEY FACTORS. PRECIPITATION CURRENTLY OVER DEEP SOUTH HANDLED QUITE WELL BY GFS. LATEST RADAR TRENDS SHOW AREA ADVANCING NORTHEAST/EAST FAIRLY QUICKLY. HEAVIER MIX PRECIP CURRENTLY INTO NORTH AND NORTH CENTRAL GEORGIA WITH SOME LIGHTER ECHOES ALOFT NOW OVER CENTRAL CWA. SOME DIFFERENCES EXIST BETWEEN NAM/GFS WHILE THERE ARE SIMILARITIES. NAM IS THE COLDEST AND WETTEST. NAM BRINGS CORE OF HIGHEST PRECIP ACROSS THE CWA WHILE GFS MOVES ACROSS MAINLY SOUTHERN SECTIONS. ALSO NAM HAS MORE PRONOUNCED INSITU WEDGE AND PROFILES FOR GSO/RDU BELOW FREEZING THROUGH 18Z INDICATING A LONGER PERIOD OF SNOW. GFS WEAKER ON INSITU WEDGE AND PROFILES INDICATE PRECIP TRANSITIONING OVER SLEET/FREEZING RAIN BY THE AFTERNOON. TOUGH CALL AS GFS HAS BEEN FAIRLY CONSISTENT AND PERFORMANCE GOOD SO FAR THIS WINTER. GFS PARTIALS ARE MORE IN LINE WITH LATEST GSO RAOB (06Z). 06Z GSO SOUNDING SHOWING QUITE A BIT OF MID LEVEL DRY AIR. PER GFS GOOD ISENTROPIC LIFT COMMENCES OVER CWA AT 12Z WHILE NAM FURTHER SOUTH AND SOUTHWEST. BOTH NAM/GFS SHOWING TWO ROUNDS OF PRECIP MOVING ACROSS THE AREA...ONE DURING THE DAY...THEN ANOTHER WITH SECOND WAVE 00Z-06Z. OVERALL WILL LEAN TOWARD GFS WITH MODIFICATION. WILL HOLD ON TO ALL SNOW LONGER IN NORTHWEST PIEDMONT. ALSO SLOWER TREND ON TRANSITION OF PRECIP IN EASTERN PIEDMONT TO ALL RAIN. ADDITIONALLY WILL ADJUST TEMPERATURE TRENDS TO KEEP COLDER THROUGH 00Z. FOR FRIDAY WILL KEEP DRIZZLE MENTIONED THROUGH MID MORNING. --RA FRIDAY NIGHT THROUGH SATURDAY NIGHT... AT THIS POINT WILL CONTINUE CURRENT FORECAST TREND. DRY AND COLD. LONG TERM /SUNDAY THROUGH WEDNESDAY/... BROAD UPPER LEVEL TROUGH REMAIN ANCHORED OVER THE AREA THROUGH THE PERIOD TO REINFORCE COLD AIR OVER THE AREA. AT THE SURFACE HIGH PRESSURE BUILDS OVER THE AREA SUNDAY. SUNDAY NIGHT...A BOUNDARY DEVELOPS ALONG THE VIRGINIA/NORTH CAROLINA BORDER AND EXTENDS WEST AND SOUTHWEST TO TENNESSEE...THEN TO A LOW OVER EASTERN TEXAS. THERE IS SOME MOISTURE AND WEAK UPPER SUPPORT ASSOCIATED WITH THIS FEATURE ..HOWEVER WILL LEAVE FORECAST DRY AT THE PRESENT TIME. THIS SYSTEM WILL BE PUSHED TO THE SOUTHEAST LATE MONDAY AND EARLY TUESDAY AS ARCTIC HIGH PRESSURE BUILDS OVER THE AREA...AND REMAINS OVER THE REGION THROUGH WEDNESDAY. THE RESULT OF THIS ARCTIC AIRMASS WILL BE BELOW TO MUCH BELOW NORMAL TEMPERATURES. -RHJ AVIATION /07Z-06Z/... ALTOCUMULUS BEGINNING TO MOVE INTO THE FOOTHILLS AT THIS TIME. CLOUDS WILL LOWER OVERNIGHT AND LIKELY DROP BELOW VFR A COUPLE OF HOURS AFTER SUNRISE AT THE TAF LOCATIONS. CEILINGS BELOW 1000 FEET ONCE PRECIPITATION BEGINS WITH MVFR VISIBILITIES IN GENERAL. CEILINGS BELOW 600 FEET MOST OF THE AFTERNOON AND INTO THE NIGHT. ALL TAF SITES EXPECTING SOME NON-LIQUID PRECIPITATION THURSDAY WITH FAYETTEVILLE HAVING THE LEAST IMPACT AND SHORTEST DURATION...AND GREENSBORO AND WINSTON-SALEM MOST IMPACTED BY WINTER WEATHER. ACCUMULATING SNOW THURSDAY MORNING WILL MIX WITH SLEET AND CHANGE TO FREEZING RAIN IN THE AFTERNOON. LESSER AMOUNTS OF SNOW AND SLEET AS ONE MOVES EAST BUT FREEZING RAIN WILL BE A CONCERN. -RLH/VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ078-085- 086-088-089. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR NCZ007>010- 021>025-038>040-073-074. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ011- 026>028-041>043-075>077-083-084. && $$ SHORT TERM...CBL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 1020 AM EST THU FEB 1 2007 .SHORT TERM /TODAY/...PRIMARILY SNOW FALLING ALONG AND WEST OF THE HIGHWAY 17 CORRIDOR AND HAVE ISSUED SNOW ADVISORIES FOR THESE AREAS UNTIL NOON. STILL ANTICIPATE ENOUGH WARMING IN THE LOW LEVELS TO CHANGE ALL PRECIPITATION TO RAIN BY MIDDAY. HAVE ALREADY SEEN SOME ACCUMULATIONS OVER GREENE...PITT...LENOIR AND DUPLIN COUNTIES WITH UP TO AN INCH AND A HALF IN LENOIR COUNTY. REST OF THE CWA WILL HAVE ALL RAIN WITH SOME DECENT QPF AMOUNTS NEAR THE COAST. HAVE ADJUSTED MAX TEMPS DOWN A COUPLE OF DEGREES AS WELL FOR THE AFTERNOON. && .AVIATION /15Z-12Z/...GENERALLY IFR WITH RAIN WITH SOME SNOW AT THE WESTERN TAF SITES (PGV, ISO) UNTIL AROUND 16 OR 17Z. && .MARINE...WILL MAKE SOME MINOR TWEAKS TO WIND DIRECTION BASED ON CURRENT OBS AND BLEND IT INTO THE RUC SOLUTIONS FOR THE AFTERNOON. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...SNOW ADVISORY UNTIL NOON EST TODAY FOR NCZ029-044-045-079-080- 090-091. MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST FRIDAY FOR AMZ130-135-150. SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SATURDAY FOR AMZ154-156-158. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST SATURDAY FOR AMZ152. && $$ COLLINS nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 839 AM EST THU FEB 1 2007 .UPDATE... CANCELED THE FREEZING RAIN ADVISORY. ALL ASOS AND MESONET SITES SEEM TO BE ABOVE FREEZING. NRN ZONES STILL SHOWING SOME SUB- FREEZING DEWPOINTS BUT WET BULB TEMPS SHOULD REMAIN ABOVE 32. KLTX SHOWING A WELL DEFINED BRIGHTBAND ACRS NRN BLADEN AND ROBESON AND TO A LESSER EXTENT MARLBORO. REPORTS FROM THESE LOCALES INDICATE THAT SOME IP AND WET SNOWFLAKES ARE MIXING WITH THE RAIN. ZFP AND GRIDS WILL IDICATE AS SUCH. RUC SOUNDINGS INIDCATE THAT BY 15Z OR 16Z THAT WETBULB TEMP WILL BE FREEZING OR ABOVE THROUGH ABOUT 800MB AT WHICH TIME ANY AND ALL MIXING SHOULD BE OVER WITH. && .PREV DISCUSSION... /ISSUED 645 AM EST THU FEB 1 2007/ SHORT TERM /THROUGH TODAY/... REGIONAL RADAR LOOPS AND SURFACE OBSERVATIONS SHOW PRECIPITATION HAS BEEN SLOW TO DEVELOP ACROSS THE AREA. IT APPEARS THE GFS DEPICTION...WHICH HAS BEEN THE MODEL OF CHOICE...IS A LITTLE TOO QUICK TO DEVELOP PRECIP. NONETHELESS...LIGHT RAIN WILL STILL DEVELOP LATER THIS MORNING ACROSS WESTERN AREAS WHERE TEMPERATURES ARE CRITICAL. INTENSE SOUNDING SCRUTINY SHOW A WINDOW OF OPPORTUNITY FOR SOME LIGHT FREEZING RAIN ACROSS WEST AND NORTHWESTERN AREAS AS WET BULB TEMPS ARE AT OR SLIGHTLY BELOW FREEZING. INTERESTING ENOUGH...IN THE FAR NORTHWEST CORNER OF THE AREA TOP DOWN ANALYSIS ACTUALLY SHOWS THE POSSIBILITY FOR A BRIEF PERIOD OF SNOW...WITH WARM NOSE TEMPS. AROUND 2 DEGREES CELSIUS. WILL REFRAIN FROM THE MENTION OF SNOW HOWEVER. ALL OF THIS SAID...HAVE EXPANDED THE FREEZING RAIN ADVISORY TO INCLUDE ROBESON...BLADEN COUNTIES IN NORTH CAROLINA WHILE ADDING DILLON...FLORENCE...AND MARION COUNTIES IN SOUTH CAROLINA. ALL PRECIP. SHOULD BE RAIN BY 1500 UTC. FOR THE REMAINDER OF THE DAY...DEEP LAYER OMEGA...MAXIMIZED AROUND 1800 UTC...WARRANTS CATEGORICAL POPS ALL AREAS. BASICALLY USED A BLEND OF GUIDANCE NUMBERS AS THERE ARE NO DISCERNIBLE TRENDS IN THE PRODUCTS. SHOULD SEE UPPER 40S ALONG THE COAST WITH AROUND 40 WESTERN AREAS. MID TERM /TONIGHT THROUGH SATURDAY/... NO CONCERNS ABOUT WINTRY PRECIPITATION THIS PERIOD AS TEMPS WILL STAY ABOVE FREEZING THROUGH TONIGHT. TWO MAIN AREAS OF LOW PRESSURE WILL MOVE NE ALONG A COASTAL TROUGH TONIGHT EACH ACCOMPANIED BY A SLUG OF DEEP MOISTURE EMBEDDED IN A DEEP SW FLOW. JUXTAPOSITION OF THE TROUGH WILL ULTIMATELY DETERMINE THE TRACK OF LOW PRESSURE AND THE AMOUNT OF RAINFALL THE AREA RECEIVES. AT THIS TIME...STORM TOTAL QPF LOOKS TO BE HIGHEST ALONG THE COAST WHERE AROUND 2 INCHES COULD FALL WITH AMOUNTS CLOSER TO AN INCH WELL INLAND. HOWEVER...THAT BEING SAID...AMOUNTS OVER 3 INCHES WILL LIKELY BE LURKING JUST OFFSHORE. ONE INCH TO AROUND TWO INCHES OF RAIN WILL BE ENOUGH FOR SIGNIFICANT PONDING OF WATER IN LOW LYING AREA...BUT A FLOOD WATCH IS NOT WARRANTED. THIS AMOUNT OF RAIN WILL LIKELY BE ENOUGH TO SEND SOME RIVERS TO OR OVER FLOOD STAGE DURING THE WEEKEND. RAIN SHOULD COME TO AN END FROM SW TO NE LATE TONIGHT...PERHAPS LINGERING TO AROUND DAYBREAK FAR NE. LOW LEVEL INVERSION IS EXPECTED TO BREAK MID TO LATE MORNING ON FRI AND THIS SHOULD ALLOW DRIER AIR AND STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE. SW TO W WINDS WILL ALLOW TEMPS TO REBOUND NICELY SO MOST AREAS SHOULD CRACK 50 DEG...PERHAPS TOUCHING NEAR 60 IN A FEW SPOTS. HIGH PRESSURE OF PACIFIC ORIGIN WILL BUILD SOLIDLY ACROSS THE CAROLINAS FRI NIGHT AND SAT. TEMPS WILL BE NEAR NORMAL TO SLIGHTLY ABOVE AND NO PRECIPITATION IS EXPECTED. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...HIGH PRESSURE WILL GET SHUNTED S AND E LATE IN THE WEEKEND. MONDAY NIGHT...AN ARCTIC FRONT WILL BLAST ACROSS THE EASTERN CAROLINAS BRINGING IN THE COLDEST AIRMASS OF THE SEASON. 1000-500 MB THICKNESSES ON THE 12Z GFS DROP AS LOW AS 519DM ACROSS THE NORTH CAROLINA COUNTIES...EQUATING TO HIGHS ONLY IN THE 30S-LOW 40S WITH LOWS DEEP INTO THE TEENS. TUESDAY NIGHT WILL LIKELY BE THE COLDEST NIGHT EVEN IF THE GFS IS CORRECT IN KEEPING WINDS UP AND THE ATMOSPHERE FROM DECOUPLING. IF THE HIGH IS A LITTLE FARTHER EAST AND WINDS DO DECOUPLE...WATCH FOR THE POSSIBILITY OF SINGLE-DIGIT LOWS FOR SOME INLAND AREAS...AND POTENTIALLY THE COLDEST TEMPERATURES SINCE FEB 5 1996. AVIATION...UPDATED LOOKS LIKE ONLY CHANCE OF FROZEN OR FREEZING PRECIP WILL BE FOR LBT ONLY THROUGH 14Z WITH ALL RAIN AFTERWARDS. CEILINGS WILL LOWER TO IFR OVER WESTERN TERMINALS BY MID MORNING WITH IFR CEILINGS ALONG THE COAST BY EARLY AFTERNOON. PRECIP WILL GET FAIRLY HEAVY LATER TODAY AS COASTAL LOW DEVELOPS ALONG WITH STRONG OMEGA. CEILINGS/VIS WILL STABLIZE...BOTH IFR...FOR ALMOST THE REMAINDER OF THE FORECAST PERIOD. WINDS WILL LIKLY BE VARIABLE ALONG THE COAST THIS AFTERNOON AND EVENING AS THE LOW TRACKS NORTHEASTWARD...WITH ALL NORTHEAST WINDS OVER FLO AND LBT. MARINE... SHORT TERM /THROUGH TODAY/... STRONG SOUTH TO SOUTHWESTERLY FLOW WILL DEVELOP ACROSS THE COASTAL WATERS LATER TODAY AS COASTAL TROUGH DEVELOPS AND HOVERS ALONG THE COAST. ALTHOUGH THE TIMING WILL BE DELAYED SOMEWHAT...WILL MAINTAIN SMALL CRAFT ADVISORY ALL WATERS BEGINNING AT 9 AM THIS MORNING FOR THE SAKE OF CONTINUITY. MID TERM /TONIGHT THROUGH SATURDAY/... COASTAL TROUGH WILL BE SITUATED ACROSS THE WATERS TONIGHT...WITH TWO AREAS OF LOW PRESSURE EXPECTED TO MOVE ALONG THIS TROUGH. WINDS WILL GET A LITTLE ERRATIC AS THESE AREAS OF LOW PRESSURE MOVE ACROSS THE AREA. GENERALLY STRONG SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TONIGHT WITH THE PREDOMINATE WIND DIRECTION FROM THE N...SHIFTING TO THE NW OVERNIGHT. SEAS WILL BE PEAKING TONIGHT IN 6 TO 9 FT RANGE. NEAR SHORE...OFFSHORE WINDS WILL KEEP SEAS CLOSER TO 5 FT. WINDS WILL BE SLOW TO DIMINISH ON FRI AS GRADIENT WILL BE SLOW TO RELAX DUE TO PRESSURE DIFFERENCES BETWEEN DEPARTING AND INTENSIFYING AREA OF LOW PRESSURE TO NE AND HIGH PRESSURE BUILDING IN FROM THE W. WINDS AND SEAS WILL CONTINUE TO LOWER FRI NIGHT AND SAT AS HIGH PRESSURE BUILDS ACROSS THE WATERS. LONG TERM /SATURDAY NIGHT THROUGH MONDAY/... A STALLED FRONT WILL REMAIN WELL OFFSHORE THROUGH THE PERIOD WITH COLD NORTHERLY FLOW CONTINUING THROUGH THE WEEKEND. RAW...BLUSTERY WEATHER IS EXPECTED TO DEVELOP SATURDAY NIGHT INTO SUNDAY AS MOISTURE OVERRUNNING THE FRONT PRODUCES AREAS OF RAIN ACROSS THE COASTAL WATERS. SURFACE HIGH PRESSURE WILL MOVE SLOWLY EAST FROM THE MID-MISSISSIPPI VALLEY SATURDAY INTO THE CENTRAL APPALACHIANS BY SUNDAY EVENING. THE 12Z GFS LOOKS VERY SIMILAR TO THE PREVIOUS FORECAST AND IS THE BASIS FOR THIS WIND FORECAST. WAVEWATCH SEAS ALSO LOOK GOOD. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 4 PM EST FRIDAY FOR AMZ254-256. SMALL CRAFT ADVISORY FROM NOON TODAY TO 7 PM EST FRIDAY FOR AMZ250-252. && $$ UPDATE...MBB SHORT TERM...SHK MID TERM...RJD LONG TERM...TRA AVIATION...DL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 433 AM CST THU FEB 1 2007 .SHORT TERM (TODAY-SUN)...LIGHT SNOW IS ONGOING ACROSS THE AREA AND ALREADY APPROACHING A HALF INCH ACCUMULATED FOR SOME PLACES. ARCTIC FRONT WILL SOON REACH YBR AND YWG AND ENTER THE U.S. AT LEAST BY 15Z. CLEARING LINE FOLLOWS THE FRONT BUT ANY CLEARING WILL LAST ONLY A FEW HOURS WITH MORE HIGH CLOUDS ALREADY MOVING SOUTH IN CENTRAL MANITOBA. AND CLEARING MIGHT NOT AS NOTICEABLE ANYWAY BECAUSE OF BLOWING SNOW. ONLY 25 TO 30 KNOTS OF WIND IS AVAILABLE TO MIX TOWARDS SURFACE TODAY FROM 925-850 MB. SUFFICIENTLY ADIABATIC LAPSE RATE SHOULD ALLOW THIS TO OCCUR AS COLD ADVECTION AT THOSE LEVELS CONTINUE THROUGH THE DAY. BUT THE SURFACE PRESSURE GRADIENT ALONE IS ENOUGH TO PRODUCE ABOUT 20 KNOTS SUSTAINED WHICH MAY PICK THE ACCUMULATING FLUFF AND SUBSTANTIALLY REDUCE VISIBILITIES MOST OF TODAY. RUC SHOWS BOUNDARY LAYER WINDS IN EXCESS OF 20 KNOTS FROM THE NORTHERN RED RIVER VALLEY WESTWARD BY 18Z AND BELIEVE THIS IS SUFFICIENT TO SUPPORT SNOW AND BLOWING SNOW ADVISORY CONDITIONS... AND DID SO FOR JUST WEST OF THE VALLEY. BUT WILL HAVE TO WATCH FOR A POSSIBLE EXTENSION OF THE ADVISORY THROUGH THE VALLEY NORTH OF FARGO. BITTER COLD FOLLOWS FOR TONIGHT AND A LONG TERM WIND CHILL ADVISORY WILL ALMOST CERTAINLY BE NECESSARY...POSSIBLY LASTING UNTIL WE REACH WIND CHILL WARNING CRITERIA ACROSS MOST OF THE REGION FOR FRIDAY NIGHT/SAT MORNING. MOSTLY CLOUDY CONDITIONS FRIDAY THROUGH SATURDAY WILL NOT HELP KEEP THE SURFACE MUCH WARMER AS THEY USUALLY DO THIS TIME OF YEAR. IN-CLOUD TEMPERATURES IN EXCESS OF -30C WILL NOT RADIATE ENOUGH TO WARM THE SURFACE. .LONG TERM...NO CHANGE TO EXTENDED FORECAST BEYOND SUNDAY. MEX GUIDANCE AND GFS SHOW GOOD PERSISTENCE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS AFTERNOON FOR NDZ006-007-014-015-024-026-054. WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 PM CST THIS EVENING FOR NDZ028-038-049-052-053. MN...NONE. && $$ GV/ nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 954 PM CST WED JAN 31 2007 .UPDATE... A FEW AREAS OF LIGHT FREEZING DRIZZLE/RAIN CONTINUE OVER PORTIONS OF OKLAHOMA THIS EVENING. SECOND ROUND ORGANIZING OVER WEST TEXAS THIS EVENING AND APPEARS TO BE GOING AS PLANNED. LATEST NAM RUN CONTINUES TO INDICATE FAIRLY PRONOUNCED BAND OF FRONTOGENETICAL FORCING NEAR THE I-40 CORRIDOR TOMORROW MORNING...WHICH RAISES A CONCERN FOR THE POSSIBILITY OF 4 TO 6 INCH TOTALS. LAST RUN OF THE SREF AND 00Z GFS HAVE BACKED OFF...GFS WAY OFF...FROM PREVIOUS POTENTIAL. GIVEN THE LATEST GUIDANCE...AND THE FACT THAT WE ARE ALREADY MENTIONING BANDED TOTALS OF 4+...WILL HOLD OFF ON A HEAVY SNOW WARNING. MIDSHIFT WILL MONITOR RADAR/SATELLITE TRENDS AND LATEST GUIDANCE AND ISSUE IF NECESSARY. ALSO RAISED POPS CONSIDERABLY ACROSS MAINLY NORTHWEST THIRD OF OKLAHOMA THURSDAY NIGHT AND FRIDAY AS NORTHWEST FLOW SYSTEM MOVES IN. THESE SYSTEM CAN BE VERY EFFICIENT...ESPECIALLY GIVEN ACCOMPANYING LOW-MID LEVEL BAROCLINIC ZONE. && .PREV DISCUSSION... /ISSUED 406 PM CST WED JAN 31 2007/ DISCUSSION...SNOW THIS MORNING WAS MOST CONCENTRATED OVER NORTHERN OKLAHOMA...WITH 1 TO 2 INCHES. LIGHT SNOW AND SLEET ELSEWHERE WAS MORE INTERMITTENT...BUT THE FREEZING DRIZZLE WHICH FOLLOWED HAS GREATLY IMPACTED TRAVEL. THIS OCCURRED AS WESTERLY MID LEVEL WINDS AND SUBSIDENCE REMOVED MOISTURE FROM THE ICE CRYSTAL GROWTH ZONE...WHILE MOIST ISENTROPIC UPGLIDE CONTINUED AT LOWER LEVELS. THERE IS A DISTINCT BACK EDGE TO THE UPGLIDE PUSHING THROUGH CENTRAL AND SOUTHERN OKLAHOMA THIS AFTERNOON. A COLD FRONT WILL ALSO MOVE INTO WESTERN OKLAHOMA AND NORTH TEXAS THIS EVENING...SO LOW LEVEL DOWNGLIDE WILL BE THE RULE OVERNIGHT...HOPEFULLY PREVENTING ANY MORE FREEZING DRIZZLE. MEANWHILE...WE STILL APPEAR ON TRACK TO RECEIVE A SWATH OF SNOW LATE TONIGHT AND THURSDAY MORNING. ALTHOUGH NOT ESPECIALLY HEAVY...ACCUMULATIONS WILL OCCUR EITHER SIDE OF THE THURSDAY MORNING COMMUTE...AGAIN IMPACTING TRAVEL. WE ARE ALSO CONCERNED THAT FREEZING RAIN WILL IMPACT PARTS OF SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS LATER TONIGHT. ORIGINALLY...THIS WAS EXPECTED TO BE RAIN...BUT TEMPERATURES ARE A COUPLE OF DEGREES COOLER THAN EXPECTED THIS AFTERNOON. DEWPOINTS ARE STILL WELL BELOW FREEZING...AND SURFACE WINDS WILL SWING AROUND TO EAST AND NORTHEAST OVERNIGHT. THEREFORE...WILL ISSUE A WINTER WEATHER ADVISORY FOR A ROW OF COUNTIES SOUTH OF THE SNOW ADVISORY. REALLY DIFFICULT TO DRAW THE FREEZING LINE EVEN 12 HOURS AHEAD OF TIME...BUT OUR ADVISORY WILL BE BASED LARGELY ON THE 18Z RUC SURFACE TEMPERATURES AND SHORT RANGE ENSEMBLE 850 MB TEMPS. WHILE MOST AREAS WILL SEE ADDITIONAL PRECIP...THERE IS STILL BELOW AVERAGE CONFIDENCE IN WHERE TO PLACE THE HIGHEST AMOUNTS. THE NAM HAS LATCHED ONTO THE LOW LEVEL FRONTOGENESIS NEAR THE RED RIVER...WHILE THE GFS PAINTS MORE SNOW ALONG THE MID LEVEL FRONT FROM WESTERN INTO CENTRAL OKLAHOMA. BOTH AREAS ARE LIKELY TO SEE LIGHT ACCUMULATIONS...BUT THE MORE CONSISTENT SIGNAL...AND LESS CHANCE FOR MELTING IS WITH THE ACTIVITY FORECAST TO SURROUND INTERSTATE 40 BOTH NORTH AND SOUTH. WILL CONTINUE WITH OUR FORECAST OF 1 TO 3 INCHES OF SNOW OVER A BROAD AREA...BUT MESOSCALE BANDING AND/OR SOME WEAK CONVECTION MAY LEAD TO HIGHER TOTALS IN SMALL AREAS. WHATEVER DOES FALL WILL LIKELY REMAIN ON THE GROUND THROUGH THE WEEKEND...AS THURSDAY AFTERNOON AND NIGHT REMAIN CLOUDY...AND AN ARCTIC FRONT ARRIVES FRIDAY. LOW LEVEL MOISTURE WILL ALSO LINGER IN THE AREA LATE THURSDAY...AND LIGHT SNOW OR FREEZING RAIN SEEMS A POSSIBILITY. WILL INCREASE TO CHANCE POPS ALONG THE STALLED LOW LEVEL FRONT NEAR THE RED RIVER...AND ALONG THE APPROACHING ARCTIC FRONT IN THE NORTHWEST. EXPECT THIS PRECIP WOULD BE LIGHT...BUT AS WE HAVE SEEN...IT DOES NOT TAKE MUCH TO CAUSE PROBLEMS. IN THE EXTENDED...THE LONGWAVE PATTERN SEEMS UNLIKELY TO BUDGE...WITH WHAT LOOKS LIKE AN OMEGA BLOCK ON AN UNUSUALLY LARGE SCALE...FROM THE PACIFIC ACROSS NORTH AMERICA. THE RIDGE IN THE BLOCK MAY TEND TO MOVE EAST BUT ALSO BE BATTED BACK BY LOW LEVEL COLD AIR INTRUSIONS OUT OF CENTRAL CANADA. SO WILL CONTINUE A COOL FORECAST...BUT WITH A VERY SLOW WARMING TREND. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 25 32 20 26 / 90 80 40 40 HOBART OK 26 31 21 28 / 90 60 40 40 WICHITA FALLS TX 32 36 26 32 / 80 50 30 30 GAGE OK 20 29 16 21 / 60 20 60 60 PONCA CITY OK 20 29 16 22 / 60 50 40 40 DURANT OK 32 38 28 35 / 80 80 20 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ004>044. WINTER WEATHER ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ045>048- 051-052. TX...SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR TXZ083. WINTER WEATHER ADVISORY UNTIL 12 PM CST THURSDAY FOR TXZ084>086. && $$ 11/25 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 406 PM CST WED JAN 31 2007 .DISCUSSION...SNOW THIS MORNING WAS MOST CONCENTRATED OVER NORTHERN OKLAHOMA...WITH 1 TO 2 INCHES. LIGHT SNOW AND SLEET ELSEWHERE WAS MORE INTERMITTENT...BUT THE FREEZING DRIZZLE WHICH FOLLOWED HAS GREATLY IMPACTED TRAVEL. THIS OCCURRED AS WESTERLY MID LEVEL WINDS AND SUBSIDENCE REMOVED MOISTURE FROM THE ICE CRYSTAL GROWTH ZONE...WHILE MOIST ISENTROPIC UPGLIDE CONTINUED AT LOWER LEVELS. THERE IS A DISTINCT BACK EDGE TO THE UPGLIDE PUSHING THROUGH CENTRAL AND SOUTHERN OKLAHOMA THIS AFTERNOON. A COLD FRONT WILL ALSO MOVE INTO WESTERN OKLAHOMA AND NORTH TEXAS THIS EVENING...SO LOW LEVEL DOWNGLIDE WILL BE THE RULE OVERNIGHT...HOPEFULLY PREVENTING ANY MORE FREEZING DRIZZLE. MEANWHILE...WE STILL APPEAR ON TRACK TO RECEIVE A SWATH OF SNOW LATE TONIGHT AND THURSDAY MORNING. ALTHOUGH NOT ESPECIALLY HEAVY...ACCUMULATIONS WILL OCCUR EITHER SIDE OF THE THURSDAY MORNING COMMUTE...AGAIN IMPACTING TRAVEL. WE ARE ALSO CONCERNED THAT FREEZING RAIN WILL IMPACT PARTS OF SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS LATER TONIGHT. ORIGINALLY...THIS WAS EXPECTED TO BE RAIN...BUT TEMPERATURES ARE A COUPLE OF DEGREES COOLER THAN EXPECTED THIS AFTERNOON. DEWPOINTS ARE STILL WELL BELOW FREEZING...AND SURFACE WINDS WILL SWING AROUND TO EAST AND NORTHEAST OVERNIGHT. THEREFORE...WILL ISSUE A WINTER WEATHER ADVISORY FOR A ROW OF COUNTIES SOUTH OF THE SNOW ADVISORY. REALLY DIFFICULT TO DRAW THE FREEZING LINE EVEN 12 HOURS AHEAD OF TIME...BUT OUR ADVISORY WILL BE BASED LARGELY ON THE 18Z RUC SURFACE TEMPERATURES AND SHORT RANGE ENSEMBLE 850 MB TEMPS. WHILE MOST AREAS WILL SEE ADDITIONAL PRECIP...THERE IS STILL BELOW AVERAGE CONFIDENCE IN WHERE TO PLACE THE HIGHEST AMOUNTS. THE NAM HAS LATCHED ONTO THE LOW LEVEL FRONTOGENESIS NEAR THE RED RIVER...WHILE THE GFS PAINTS MORE SNOW ALONG THE MID LEVEL FRONT FROM WESTERN INTO CENTRAL OKLAHOMA. BOTH AREAS ARE LIKELY TO SEE LIGHT ACCUMULATIONS...BUT THE MORE CONSISTENT SIGNAL...AND LESS CHANCE FOR MELTING IS WITH THE ACTIVITY FORECAST TO SURROUND INTERSTATE 40 BOTH NORTH AND SOUTH. WILL CONTINUE WITH OUR FORECAST OF 1 TO 3 INCHES OF SNOW OVER A BROAD AREA...BUT MESOSCALE BANDING AND/OR SOME WEAK CONVECTION MAY LEAD TO HIGHER TOTALS IN SMALL AREAS. WHATEVER DOES FALL WILL LIKELY REMAIN ON THE GROUND THROUGH THE WEEKEND...AS THURSDAY AFTERNOON AND NIGHT REMAIN CLOUDY...AND AN ARCTIC FRONT ARRIVES FRIDAY. LOW LEVEL MOISTURE WILL ALSO LINGER IN THE AREA LATE THURSDAY...AND LIGHT SNOW OR FREEZING RAIN SEEMS A POSSIBILITY. WILL INCREASE TO CHANCE POPS ALONG THE STALLED LOW LEVEL FRONT NEAR THE RED RIVER...AND ALONG THE APPROACHING ARCTIC FRONT IN THE NORTHWEST. EXPECT THIS PRECIP WOULD BE LIGHT...BUT AS WE HAVE SEEN...IT DOES NOT TAKE MUCH TO CAUSE PROBLEMS. IN THE EXTENDED...THE LONGWAVE PATTERN SEEMS UNLIKELY TO BUDGE...WITH WHAT LOOKS LIKE AN OMEGA BLOCK ON AN UNUSUALLY LARGE SCALE...FROM THE PACIFIC ACROSS NORTH AMERICA. THE RIDGE IN THE BLOCK MAY TEND TO MOVE EAST BUT ALSO BE BATTED BACK BY LOW LEVEL COLD AIR INTRUSIONS OUT OF CENTRAL CANADA. SO WILL CONTINUE A COOL FORECAST...BUT WITH A VERY SLOW WARMING TREND. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 27 32 20 26 / 90 70 20 30 HOBART OK 27 31 21 28 / 90 40 30 30 WICHITA FALLS TX 32 36 26 32 / 80 40 30 30 GAGE OK 20 29 16 21 / 60 20 30 30 PONCA CITY OK 21 29 16 22 / 60 50 20 20 DURANT OK 32 38 28 35 / 80 70 30 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR OKZ014>019-021>032-040-042. SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ014>019-021>044. SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ004>013-020. WINTER WEATHER ADVISORY UNTIL 12 PM CST THURSDAY FOR OKZ045>048- 051-052. TX...SNOW ADVISORY UNTIL 12 PM CST THURSDAY FOR TXZ083. WINTER WEATHER ADVISORY UNTIL 12 PM CST THURSDAY FOR TXZ084>086. && $$ BURKE/SIX ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 813 PM CST WED JAN 31 2007 .DISCUSSION... ALREADY HAVE HAD A QUICK SHOT OF SNOW ACROSS SOUTHERN HALF OF MIDDLE TN THIS EVE...WITH AREAS OVER ERN AR AND WRN TN GETTING UP TO 2 INCHES AS IT MOVED ACROSS THAT AREA. SOME OF OUR COUNTIES HAVE LIKELY HAD A DUSTING...A PREVIEW IF YOU WILL. LOOKING NOW AT BAND OF MODERATE TO HEAVY SLEET ACROSS CNTRL MS MOVING NE...THIS WILL POSSIBLY BE OUR FIRST MEASURABLE EPISODE FOR THIS EVENT...AND SHOULD BE IN FORM OF SNOW AS RUC SOUNDING FOR FYM SHOWS ALL SNOW ACROSS FAR SOUTHERN TN UNTIL ABOUT 09Z. MAY HAVE TO UPDATE FOR TIMING IF THIS BAND MOVES IN B4 MIDNITE. && .PREV DISCUSSION... /ISSUED 149 PM CST WED JAN 31 2007/ SHORT TERM...MODELS ARE IN REASONABLE AGREEMENT FOR MID TN WX...ESPECIALLY FOR A WINTER EVENT. GFS SEEMS CONSISTENT WITH THERMAL PROFILES FROM PREVIOUS RUN AND NAM ACTUALLY APPEARS A LITTLE COLDER IN THE NORTH AND PLATEAU. THIS MAY MEAN PRECIPITATION WILL STAY SNOW LONGER THEN PREVIOUSLY THOUGHT FOR THE NORTH HALF. QPF AND SNOWFALL OUTPUT FROM MODELS ACTUALLY IN PRETTY GOOD AGREEMENT AS WELL FOR MID TN. WITH ALL OF THIS SAID...SNOW IS HARD TO COME BY IN THIS REGION SO THERE ARE MANY THINGS THAT CAN SPOIL THIS EVENT (LACK OF MOISTURE...TOO WARM). THIS FORECAST IS NOT A BIG CHANGE FROM PREVIOUS PACKAGE...BUT THE LATEST MODEL DATA HAVE HELPED LEAN US TOWARD A STRONGER HEADLINE ON THE NORTH PLATEAU. AIR MASS IN PLACE IS COLD...TEMPERATURES NOT REACHING PROJECTED HIGHS TODAY ALTHOUGH WE MAY JUMP A FEW MORE DEGREES INTO THE LOW 30S LATE THIS AFTERNOON. MOISTURE WILL SPREAD RAPIDLY ACROSS THE REGION TONIGHT WITH ALL SIGNS POINTING TOWARD SNOW. VERY DRY LOW LEVELS WILL TAKE A WHILE TO MOISTEN...BUT MOST AREAS COULD HAVE AROUND 1 INCH BY DAYBREAK THURSDAY. FOR SOUTHERN TIER OF COUNTIES...SNOW WILL OCCUR TONIGHT WITH MAYBE AN INCH...BUT WILL QUICKLY TRANSITION TO RAIN THURSDAY MORNING. THERE MAY BE A MESSY TIME WITH FREEZING RAIN AND SLEET...BUT TEMPERATURES SHOULD WARM WELL INTO THE 30S BY LATE MORNING. FOR AREAS FARTHER NORTH...SNOW WILL DEVELOP LATE TONIGHT AND CONTINUE THROUGH MID MORNING THURSDAY. THEN THE MIX OF CHANGE TO SLEET AND RAIN WILL OCCUR AFTER 16Z WITH TEMPERATURES RISING ABOVE FREEZING. THESE AREAS INCLUDING NASHVILLE WILL PROBABLY SEE 1 TO 2 INCHES BEFORE MIDDAY. MOST OF THE MID STATE WILL BE UNDER AN ADVISORY WHILE THE HIGHER ELEVATIONS OF THE NORTH PLATEAU ARE EXPECTED TO REACH WINTER STORM WARNING CRITERIA. FORECAST SOUNDINGS SUGGEST MAINLY SNOW THROUGH MUCH OF THE DAY FOR CROSSVILLE AND JAMESTOWN...SO WE ARE FORECASTING UP TO 4 INCHES THERE. STILL A CHANCE OF PRECIPITATION LATE THURSDAY AND INTO THE NIGHT...BUT MARGINAL TEMPERATURES AND LIGHT PRECIP...SO NOT CALLING FOR ADDITIONAL ACCUMULATIONS AT THIS TIME. TEMPERATES MAY FALL BELOW FREEZING CAUSING MORE TRAVEL PROBLEMS. LONG TERM...A SERIES OF COLD BLASTS WILL INVADE THE REGION IN THE EXTENDED FORECAST. DISTURBANCES MAY BRING PERIODS OF SNOW SHOWERS AND LOCALIZED MINOR SNOW ACCUMULATIONS. FOR NOW JUST MENTIONING SOME FLURRIES WITH MOST SIGNIFICANT FRONTS. FOCUS SHOULD BE ON VERY COLD READINGS...WHICH WILL HAVE MOST AREAS IN THE SINGLE DIGITS FOR LOWS AND ONLY 20S FOR HIGHS EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 26 37 30 36 / 90 100 70 10 CLARKSVILLE 26 33 28 34 / 90 100 70 10 CROSSVILLE 25 33 29 33 / 90 100 70 20 && .OHX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM MIDNIGHT THURSDAY TO 4 PM THURSDAY FOR THE FOLLOWING ZONES: CUMBERLAND...FENTRESS...OVERTON...PICKETT... PUTNAM...VAN BUREN...AND WHITE. WINTER WEATHER ADVISORY FROM MIDNIGHT THURSDAY TO 4 PM THURSDAY FOR THE FOLLOWING ZONES: BENTON...CANNON...CHEATHAM...CLAY... DAVIDSON...DEKALB...DICKSON...HICKMAN...HOUSTON...HUMPHREYS... JACKSON...MACON...MONTGOMERY...PERRY...ROBERTSON...RUTHERFORD... SMITH...STEWART...SUMNER...TROUSDALE...WARREN...WILLIAMSON...AND WILSON. WINTER WEATHER ADVISORY FROM MIDNIGHT THURSDAY TO 10 AM THURSDAY FOR THE FOLLOWING ZONES: BEDFORD...COFFEE...GILES...GRUNDY... LAWRENCE...LEWIS...MARSHALL...MAURY...AND WAYNE. && $$ MAG tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 342 PM CST WED JAN 31 2007 .UPDATE... QUICK UPDATE TO ADD MISSISSIPPI COUNTY IN ARKANSAS AND LAKE...DYER AND OBION COUNTIES IN TENNESSEE TO THE SNOW ADVISORTY. RADAR AND SURFACE TRENDS INDICATE THE SNOW MOVING EAST. ROAD CONDITIONS GETTING SLIPPERY VERY QUICKLY DUE TO COLD TEMPERATURES. LATEST RUC MODEL SOME HELP WITH PROGRESSION OF SNOWFALL...BUT STRONGER LOW LEVEL COLD AIR THAN ANTICIPATED PROVIDING BETTER THAN FORECAST ISENTROPIC UPGLIDE FOR LIFTED MOTION && .PREV DISCUSSION... /ISSUED 302 PM CST WED JAN 31 2007/ SYNOPSIS... COLD HIGH RETREATING OFF THE EAST COAST. RADAR TRENDS SHOW PRECIPITATION BREAKING OUT ACROSS THE PLAINS AND ARKANSAS THIS AFTERNOON. WITH THE LOW LEVELS SO DRY...MUCH OF THE PRECIPITATION INDICATED ON RADAR IS NOT REACHING THE GROUND. HOWEVER OVER NORTHEAST ARKANSAS IT IS. WITH LOW LEVELS SO COLD SNOWFALL ACCUMULATING ON ROADS FAST. ACTUAL TEMPERATURES COLDER THAN THE MODELS BY GENERALLY 5 DEGREES. WITH MODELS NOT HANDLING THE LOW LEVEL TEMPERATURES AT THIS TIME THIS MAY HAVE IMPLICATIONS TO OUR SHORT TERM FORECAST. SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)... RADAR TRENDS SHOW SNOWFALL TO CONTINUE OVER NORTHEAST ARKANSAS FOR SOME TIME. ACCUMULATIONS OF AROUND AN INCH ARE EXPECTED. WITH TEMPS IN THE LOWER 20S ALL OF THE SNOW IS STICKING NICELY. HAVE DECIDED TO GO WITH AN ADVISORY THROUGH MID-MORNING THURSDAY. FOR THE REST OF THE AREA MIXED PRECIPITATION EXPECTED AFTER MIDNIGHT THROUGH THURSDAY FOR MUCH OF THE MID-SOUTH. MUCH OF THE LIFT FOR THIS EVENT IS ISENTROPIC AND BROAD IN NATURE. ALTHOUGH JET STREAK IS FAIRLY STRONG THERE IS LITTLE IN THE WAY OF SURFACE CYCLOGENESIS. CONSEQUENTLY PRECIPITATION AMOUNTS WILL BE BROAD AND LIGHT THROUGH THURSDAY NIGHT. REGARDLESS...IT DOESN`T TAKE MUCH WINTER PRECIPITATION TO CAUSE TRAVEL ISSUES IN THE MIDSOUTH. THIS COUPLED WITH THE FIRST EVENT OF THE SEASON AND WE HAVE A NEED TO PINPOINT THE IMPACTS. OUR PRECIPITATION WILL COME IN TWO BURSTS. TONIGHT...MIXED PRECIPITATION IS EXPECTED TO DEVELOP WITH THE HEAVIEST OCCURRING IN NORTHEAST MISSISSIPPI IN THE LOCATION OF THE BEST ISENTROPIC LIFT AND MOISTURE. THE PROBLEM IS THERMAL PROFILES INDICATE AN ONSET OF FREEZING RAIN FROM FULTON TO TUPELO TO OXFORD. THIS IS WHERE TRAVEL WILL BE IMPACTED MOST WITH PRECIPITATION TURNING OVER TO RAIN LATER ON THURSDAY. AN ADVISORY WILL BE NEEDED IN THIS AREA LATE TONIGHT AND EARLY THURSDAY. TO THE NORTH AND NORTHWEST OF THIS AREA...THE PRECIPITATION SHOULD BEGIN AS SNOW...HOWEVER AMOUNTS ARE IN QUESTION WITH ACCUMULATIONS RANGING FROM AN INCH TO ONLY A DUSTING. THIS MAKES IT HARD TO DETERMINE WHETHER WE SHOULD ISSUE AN ADVISORY. FOR NOW WE`LL HOLD OFF AND WAIT ON ANY WIDESPREAD ADVISORIES...EXCEPT IN NORTHEAST ARKANSAS AND MISSOURI BOOTHEEL...UNTIL WE CAN GET A BETTER HANDLE ON THE EVOLUTION OF THE PRECIPITATION AMOUNTS. THURSDAY AND THURSDAY NIGHT ARE PROBLEMATIC. ANOTHER WEAK SHORTWAVE MOVES INTO MS/AL RESULTING IN PRECIPITATION REDEVELOPING IN THE AFTERNOON. AGAIN QUESTION WILL BE THE TYPE. FOR NOW BELIEVE THE MODEL THERMAL PROFILES MAY BE TOO WARM IN THE LOWER LEVELS (THEY SUGGEST A DRY ADIABATIC PROFILE WITH PRECIPITATION?) WILL KEEP RAIN FOR THE SOUTH THIRD OF THE FORECAST AREA...A MIX OF THE MIDDLE THIRD AND ALL SNOW TO THE NORTH. AGAIN PRECIPITATION AMOUNTS WILL BE LIGHT...BUT DEPENDING ON HOW TEMPERATURES PLAY OUT A WINTER WEATHER ADVISORY MAY BE NEEDED. WILL USE THE UKMET/GFS/CANADIAN FOR THURSDAY NIGHT AND FRIDAY. NAM IS TOO SLOW WITH COLD AIR SEEPING IN. CONSEQUENTLY WILL GO LOWER THAN GUIDANCE WITH FLURRIES POSSIBLE IN THE STRONG COLD AIR ADVECTION. OVERALL THE TEMPERATURE GUIDANCE THROUGH THIS PERIOD LOOKS WARM. BUT THIS SHOULD NOT BE SURPRISING WITH LOW LEVEL COLD AIR IN PLACE. ...BELLES... LONG TERM (SATURDAY THROUGH WEDNESDAY)...LONG RANGE MODELS IN GENERAL AGREEMENT WITH AN ARCTIC LOW PINWHEELING AROUND HUDSON BAY THROUGH THE PERIOD AND A LONGWAVE TROUGH MOVING THROUGH THE LOWER MISSISSIPPI VALLEY ON SUNDAY. ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION ON MONDAY WITH COLD HIGH PRESSURE BUILDING BACK INTO THE AREA FOR NEXT WEEK. ADJUSTED TEMPERATURES TOWARD THE LOW END OF THE GFS ENSEMBLE GUIDANCE SINCE OPERATIONAL GFS NUMERICAL GUIDANCE SEEMS TO BE TOO WARM THIS WEEKEND INTO EARLY NEXT WEEK BASED ON UPPER AIR PATTERN AND VERY COLD 850MB TEMPERATURES. ...CJC... && .PRELIMINARY POINT TEMPS/POPS... MEM 27 38 30 38 / 80 100 60 10 MKL 23 36 28 35 / 80 90 60 10 JBR 20 34 24 34 / 80 90 60 10 TUP 29 39 33 41 / 90 100 60 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...SNOW ADVISORY UNTIL 9 AM CST THURSDAY FOR CLAY-CRAIGHEAD-GREENE- LAWRENCE-MISSISSIPPI-RANDOLPH. MO...SNOW ADVISORY UNTIL 9 AM CST THURSDAY FOR DUNKLIN-PEMISCOT. MS...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST THURSDAY FOR ALCORN-BENTON(MS)-ITAWAMBA-LAFAYETTE-LEE(MS)- MARSHALL-PONTOTOC-PRENTISS-TIPPAH-TISHOMINGO-UNION. TN...SNOW ADVISORY UNTIL 9 AM CST THURSDAY FOR DYER-LAKE-OBION. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST THURSDAY FOR HARDEMAN-HARDIN-MCNAIRY. && $$ tn AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE FORT WORTH TX 300 PM CST THU FEB 1 2007 .AVIATION... 300 PM CST THU FEB 1 2007 HAVE UPDATED THE METROPLEX AIRPORT FOR TWO REASONS: 1. THE RAIN IS STARTING TO MIX WITH SLEET AND SNOW ACROSS THE THE AREA NORTH AND WEST OF THE TAF SITES. ALSO KAFW REPORTED -RAPL DURING THE LAST HOUR AND WE HAVE HAD -RASN HERE AT THE WFO. THUS HAVE ADDED -RAPLSN TO THE TAFS. TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING AT THE METROPLEX TAF SITES THROUGH MIDNIGHT...BUT A MIXTURE OF RAIN AND SNOW MAY CONTINUE THROUGH THE EVENING HOURS. 2. THE PREVIOUS FORECAST FOR AN IMPROVEMENT TO MVFR CEILINGS EARLY THIS EVENING LOOKS TO BE TOO OPTIMISTIC. WITH ON-GOING PRECIPITATION...THE CEILINGS ARE UNLIKELY TO IMPROVE MUCH. #58 1145 AM CST THU FEB 1 2007 LOW CLOUDS AND REDUCED VISIBILITIES WILL CONTINUE ACROSS THE TAF SITES FOR THE REST OF TODAY. CEILINGS MAY BRIEFLY RISE TO MVFR BUT HAVE GENERALLY KEPT PREVAILING IFR CEILINGS THROUGH 23Z. AFTERWARDS...WE SHOULD SEE A SLIGHT IMPROVEMENT TO LOW END MVFR INTO THE EVENING...BEFORE CEILINGS FALL BACK INTO THE IFR CATEGORY AFTER MIDNIGHT. PRECIPITATION IS EXPECTED TO REMAIN JUST RAIN THROUGH THIS EVENING AT THE METROPLEX SITES. HAVE LEFT OUT ANY MENTION OF PRECIPITATION FOR THE OVERNIGHT PERIOD...AS POPS WILL BE LOW. HOWEVER...IF PRECIPITATION DOES CONTINUE...WE COULD SEE SOME SLEET MIX IN WITH THE RAIN TOWARD MIDNIGHT...AND A SOME LIGHT SLEET/SNOW LATE TONIGHT INTO FRIDAY MORNING. WE WILL KEEP KEEP AN EYE ON THE DEVELOPING SITUATION...AND MAY NEED TO ADD SOME WINTRY PRECIPITATION FOR THE METROPLEX TAFS WITH AN UPDATE LATER THIS AFTERNOON. FARTHER SOUTH...IT WILL BE JUST RAIN AT WACO...WITH AN ISOLATED THUNDERSTORM POSSIBLE THIS AFTERNOON. NORTHERLY FLOW WILL PREVAIL AT THE METROPLEX TAF SITES. SOUTHEASTERLY FLOW AT WACO WILL COME AROUND TO THE EAST AND NORTHEAST LATE AFTERNOON/EARLY EVENING. #58 && .DISCUSSION... 936 AM CST THU FEB 1 2007 HAVE UPDATED ZONES TO INCLUDE THUNDER IN THE WESTERN HALF OF THE FORECAST AREA AS BOTH THE NAM AND GFS INDICATED 700-500MB LAPSE RATES INCREASING TO 7.0-7.5 C/KM IN THIS AREA. THERE ARE A COUPLE DECENT STORMS JUST TO THE SW OF THE CWA ALREADY. ALSO...WILL CONTINUE MENTION OF AREAS OF FOG AREAWIDE AT LEAST THROUGH 18Z WITH MANY STATIONS STILL REPORTING VISBYS IN THE 1-2 MI RANGE. ALSO ADJUSTED DEWPOINTS. /13 && .PREV DISCUSSION... /ISSUED 539 AM CST THU FEB 1 2007/ UPDATE... PRECIP SHIELD IS EXPANDING A BIT MORE THAN EARLIER ANTICIPATED. HAVE INCREASED POPS THIS MORNING AND LINGERED PRECIP LONGER THIS AFTERNOON AND EVENING DUE TO SECOND IMPULSE TRIGGERING MORE PRECIP OVER WEST TX. UPDATED PRODUCTS AVAILABLE SHORTLY. SCHULTZ AVIATION... FOR THE 12Z TAFS...-RA SHOULD BE PREVAILING THROUGH THE MID AFTERNOON HOURS. VSBYS MAY TEMPORARILY DROP INTO IFR/LIFR CAT THIS MORNING...WITH LIFR/VLIFR CIGS. VSBYS AND CIGS SHOULD RECOVER INTO MVFR CAT BY THE AFTERNOON AND INTO THE EVENING HOURS AS PRECIP TAPERS OFF. 05/21 DISCUSSION..../ISSUED 416 AM CST THU FEB 1 2007/ SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 / 100 20 10 10 WACO, TX 50 36 45 27 / 100 10 10 10 PARIS, TX 40 27 35 22 / 100 30 10 10 DENTON, TX 40 29 36 23 / 100 20 10 10 MCKINNEY, TX 40 29 35 23 / 100 20 10 10 DALLAS, TX 41 31 38 24 / 100 20 10 10 TERRELL, TX 43 31 39 23 / 100 20 10 10 CORSICANA, TX 46 33 40 24 / 100 20 10 10 TEMPLE, TX 53 37 50 29 / 100 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99 tx AREA FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE FORT WORTH TX 1145 AM CST THU FEB 1 2007 .AVIATION... LOW CLOUDS AND REDUCED VISIBILITIES WILL CONTINUE ACROSS THE TAF SITES FOR THE REST OF TODAY. CEILINGS MAY BRIEFLY RISE TO MVFR BUT HAVE GENERALLY KEPT PREVAILING IFR CEILINGS THROUGH 23Z. AFTERWARDS...WE SHOULD SEE A SLIGHT IMPROVEMENT TO LOW END MVFR INTO THE EVENING...BEFORE CEILINGS FALL BACK INTO THE IFR CATEGORY AFTER MIDNIGHT. PRECIPITATION IS EXPECTED TO REMAIN JUST RAIN THROUGH THIS EVENING AT THE METROPLEX SITES. HAVE LEFT OUT ANY MENTION OF PRECIPITATION FOR THE OVERNIGHT PERIOD...AS POPS WILL BE LOW. HOWEVER...IF PRECIPITATION DOES CONTINUE...WE COULD SEE SOME SLEET MIX IN WITH THE RAIN TOWARD MIDNIGHT...AND A SOME LIGHT SLEET/SNOW LATE TONIGHT INTO FRIDAY MORNING. WE WILL KEEP KEEP AN EYE ON THE DEVELOPING SITUATION...AND MAY NEED TO ADD SOME WINTRY PRECIPITATION FOR THE METROPLEX TAFS WITH AN UPDATE LATER THIS AFTERNOON. FARTHER SOUTH...IT WILL BE JUST RAIN AT WACO...WITH AN ISOLATED THUNDERSTORM POSSIBLE THIS AFTERNOON. NORTHERLY FLOW WILL PREVAIL AT THE METROPLEX TAF SITES. SOUTHEASTERLY FLOW AT WACO WILL COME AROUND TO THE EAST AND NORTHEAST LATE AFTERNOON/EARLY EVENING. #58 && .DISCUSSION... 936 AM CST THU FEB 1 2007 HAVE UPDATED ZONES TO INCLUDE THUNDER IN THE WESTERN HALF OF THE FORECAST AREA AS BOTH THE NAM AND GFS INDICATED 700-500MB LAPSE RATES INCREASING TO 7.0-7.5 C/KM IN THIS AREA. THERE ARE A COUPLE DECENT STORMS JUST TO THE SW OF THE CWA ALREADY. ALSO...WILL CONTINUE MENTION OF AREAS OF FOG AREAWIDE AT LEAST THROUGH 18Z WITH MANY STATIONS STILL REPORTING VISBYS IN THE 1-2 MI RANGE. ALSO ADJUSTED DEWPOINTS. /13 && .PREV DISCUSSION... /ISSUED 539 AM CST THU FEB 1 2007/ UPDATE... PRECIP SHIELD IS EXPANDING A BIT MORE THAN EARLIER ANTICIPATED. HAVE INCREASED POPS THIS MORNING AND LINGERED PRECIP LONGER THIS AFTERNOON AND EVENING DUE TO SECOND IMPULSE TRIGGERING MORE PRECIP OVER WEST TX. UPDATED PRODUCTS AVAILABLE SHORTLY. SCHULTZ AVIATION... FOR THE 12Z TAFS...-RA SHOULD BE PREVAILING THROUGH THE MID AFTERNOON HOURS. VSBYS MAY TEMPORARILY DROP INTO IFR/LIFR CAT THIS MORNING...WITH LIFR/VLIFR CIGS. VSBYS AND CIGS SHOULD RECOVER INTO MVFR CAT BY THE AFTERNOON AND INTO THE EVENING HOURS AS PRECIP TAPERS OFF. 05/21 DISCUSSION..../ISSUED 416 AM CST THU FEB 1 2007/ SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 / 100 20 10 10 WACO, TX 50 36 45 27 / 100 10 10 10 PARIS, TX 40 27 35 22 / 100 30 10 10 DENTON, TX 40 29 36 23 / 100 20 10 10 MCKINNEY, TX 40 29 35 23 / 100 20 10 10 DALLAS, TX 41 31 38 24 / 100 20 10 10 TERRELL, TX 43 31 39 23 / 100 20 10 10 CORSICANA, TX 46 33 40 24 / 100 20 10 10 TEMPLE, TX 53 37 50 29 / 100 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99 tx AREA FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE FORT WORTH TX 1145 AM CST THU FEB 1 2007 .AVIATION... LOW CLOUDS AND REDUCED VISIBILITIES WILL CONTINUE ACROSS THE TAF SITES FOR THE REST OF TODAY. CEILINGS MAY BRIEFLY RISE TO MVFR BUT HAVE GENERALLY KEPT PREVAILING IFR CEILINGS THROUGH 23Z. AFTERWARDS...WE SHOULD SEE A SLIGHT IMPROVEMENT TO LOW END MVFR INTO THE EVENING...BEFORE CEILINGS FALL BACK INTO THE IFR CATEGORY AFTER MIDNIGHT. PRECIPITATION IS EXPECTED TO REMAIN JUST RAIN THROUGH THIS EVENING AT THE METROPLEX SITES. HAVE LEFT OUT ANY MENTION OF PRECIPITATION FOR THE OVERNIGHT PERIOD...AS POPS WILL BE LOW. HOWEVER...IF PRECIPITATION DOES CONTINUE...WE COULD SEE SOME SLEET MIX IN WITH THE RAIN TOWARD MIDNIGHT...AND A SOME LIGHT SLEET/SNOW LATE TONIGHT INTO FRIDAY MORNING. WE WILL KEEP KEEP AN EYE ON THE DEVELOPING SITUATION...AND MAY NEED TO ADD SOME WINTRY PRECIPITATION FOR THE METROPLEX TAFS WITH AN UPDATE LATER THIS AFTERNOON. FARTHER SOUTH...IT WILL BE JUST RAIN AT WACO...WITH AN ISOLATED THUNDERSTORM POSSIBLE THIS AFTERNOON. NORTHERLY FLOW WILL PREVAIL AT THE METROPLEX TAF SITES. SOUTHEASTERLY FLOW AT WACO WILL COME AROUND TO THE EAST AND NORTHEAST LATE AFTERNOON/EARLY EVENING. #58 && .DISCUSSION... 936 AM CST THU FEB 1 2007 HAVE UPDATED ZONES TO INCLUDE THUNDER IN THE WESTERN HALF OF THE FORECAST AREA AS BOTH THE NAM AND GFS INDICATED 700-500MB LAPSE RATES INCREASING TO 7.0-7.5 C/KM IN THIS AREA. THERE ARE A COUPLE DECENT STORMS JUST TO THE SW OF THE CWA ALREADY. ALSO...WILL CONTINUE MENTION OF AREAS OF FOG AREAWIDE AT LEAST THROUGH 18Z WITH MANY STATIONS STILL REPORTING VISBYS IN THE 1-2 MI RANGE. ALSO ADJUSTED DEWPOINTS. /13 && .PREV DISCUSSION... /ISSUED 539 AM CST THU FEB 1 2007/ UPDATE... PRECIP SHIELD IS EXPANDING A BIT MORE THAN EARLIER ANTICIPATED. HAVE INCREASED POPS THIS MORNING AND LINGERED PRECIP LONGER THIS AFTERNOON AND EVENING DUE TO SECOND IMPULSE TRIGGERING MORE PRECIP OVER WEST TX. UPDATED PRODUCTS AVAILABLE SHORTLY. SCHULTZ AVIATION... FOR THE 12Z TAFS...-RA SHOULD BE PREVAILING THROUGH THE MID AFTERNOON HOURS. VSBYS MAY TEMPORARILY DROP INTO IFR/LIFR CAT THIS MORNING...WITH LIFR/VLIFR CIGS. VSBYS AND CIGS SHOULD RECOVER INTO MVFR CAT BY THE AFTERNOON AND INTO THE EVENING HOURS AS PRECIP TAPERS OFF. 05/21 DISCUSSION..../ISSUED 416 AM CST THU FEB 1 2007/ SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 / 100 20 10 10 WACO, TX 50 36 45 27 / 100 10 10 10 PARIS, TX 40 27 35 22 / 100 30 10 10 DENTON, TX 40 29 36 23 / 100 20 10 10 MCKINNEY, TX 40 29 35 23 / 100 20 10 10 DALLAS, TX 41 31 38 24 / 100 20 10 10 TERRELL, TX 43 31 39 23 / 100 20 10 10 CORSICANA, TX 46 33 40 24 / 100 20 10 10 TEMPLE, TX 53 37 50 29 / 100 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 936 AM CST THU FEB 1 2007 .DISCUSSION... HAVE UPDATED ZONES TO INCLUDE THUNDER IN THE WESTERN HALF OF THE FORECAST AREA AS BOTH THE NAM AND GFS INDICATED 700-500MB LAPSE RATES INCREASING TO 7.0-7.5 C/KM IN THIS AREA. THERE ARE A COUPLE DECENT STORMS JUST TO THE SW OF THE CWA ALREADY. ALSO...WILL CONTINUE MENTION OF AREAS OF FOG AREAWIDE AT LEAST THROUGH 18Z WITH MANY STATIONS STILL REPORTING VISBYS IN THE 1-2 MI RANGE. ALSO ADJUSTED DEWPOINTS. /13 && .PREV DISCUSSION... /ISSUED 539 AM CST THU FEB 1 2007/ UPDATE... PRECIP SHIELD IS EXPANDING A BIT MORE THAN EARLIER ANTICIPATED. HAVE INCREASED POPS THIS MORNING AND LINGERED PRECIP LONGER THIS AFTERNOON AND EVENING DUE TO SECOND IMPULSE TRIGGERING MORE PRECIP OVER WEST TX. UPDATED PRODUCTS AVAILABLE SHORTLY. SCHULTZ AVIATION... FOR THE 12Z TAFS...-RA SHOULD BE PREVAILING THROUGH THE MID AFTERNOON HOURS. VSBYS MAY TEMPORARILY DROP INTO IFR/LIFR CAT THIS MORNING...WITH LIFR/VLIFR CIGS. VSBYS AND CIGS SHOULD RECOVER INTO MVFR CAT BY THE AFTERNOON AND INTO THE EVENING HOURS AS PRECIP TAPERS OFF. 05/21 DISCUSSION..../ISSUED 416 AM CST THU FEB 1 2007/ SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 / 100 20 10 10 WACO, TX 50 36 45 27 / 100 10 10 10 PARIS, TX 40 27 35 22 / 100 30 10 10 DENTON, TX 40 29 36 23 / 100 20 10 10 MCKINNEY, TX 40 29 35 23 / 100 20 10 10 DALLAS, TX 41 31 38 24 / 100 20 10 10 TERRELL, TX 43 31 39 23 / 100 20 10 10 CORSICANA, TX 46 33 40 24 / 100 20 10 10 TEMPLE, TX 53 37 50 29 / 100 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99 tx AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE FORT WORTH TX 539 AM CST THU FEB 1 2007 .UPDATE... PRECIP SHIELD IS EXPANDING A BIT MORE THAN EARLIER ANTICIPATED. HAVE INCREASED POPS THIS MORNING AND LINGERED PRECIP LONGER THIS AFTERNOON AND EVENING DUE TO SECOND IMPULSE TRIGGERING MORE PRECIP OVER WEST TX. UPDATED PRODUCTS AVAILABLE SHORTLY. SCHULTZ && .AVIATION... FOR THE 12Z TAFS...-RA SHOULD BE PREVAILING THROUGH THE MID AFTERNOON HOURS. VSBYS MAY TEMPORARILY DROP INTO IFR/LIFR CAT THIS MORNING...WITH LIFR/VLIFR CIGS. VSBYS AND CIGS SHOULD RECOVER INTO MVFR CAT BY THE AFTERNOON AND INTO THE EVENING HOURS AS PRECIP TAPERS OFF. 05/21 && .DISCUSSION..../ISSUED 416 AM CST THU FEB 1 2007/ SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 41 / 80 10 10 10 10 WACO, TX 51 36 45 27 47 / 90 10 10 10 10 PARIS, TX 40 27 35 22 39 / 100 30 10 10 10 DENTON, TX 40 29 36 23 40 / 80 20 10 10 10 MCKINNEY, TX 40 29 35 23 39 / 100 20 10 10 10 DALLAS, TX 41 31 38 24 42 / 90 10 10 10 10 TERRELL, TX 43 31 39 23 43 / 100 10 10 10 10 CORSICANA, TX 48 33 40 24 44 / 90 10 10 10 10 TEMPLE, TX 53 37 50 29 48 / 90 10 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21/05/92 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 416 AM CST THU FEB 1 2007 .DISCUSSION... SHORTWAVE ENERGY IS ENTERING WEST TEXAS THIS MORNING...AND MID LEVEL SHEAR AXIS ORIENTATION IS ALIGNED WELL WITH PRECIP SHIELD. RAIN EXTENDS FROM NEAR DFW TO SOUTH OF SJT AT 10Z. SURFACE TEMPS ALONG THE RED RIVER ARE THE MAIN SHORT TERM FOCUS AS PRECIP MOVES INTO THE AREA. RUC ANALYSIS OF 850MB TEMPS KEEPS THE PUSH OF BELOW 0C TEMPS BEHIND THE PROGRESSION OF PRECIPITATION. THIS ANALYSIS SEEMS TO FIT WELL WITH THE PUSH OF THE COLD AIR AT THE SURFACE /PER SFC OBS/ WHICH IS BEST OVER FAR WESTERN OK AND THE TX PANHANDLE. FOR NOW...WILL KEEP PRECIP LIQUID IN THE ZONES TODAY...BUT WILL REEVALUATE POST 12Z SOUNDINGS AND INCOMING OBS...AND UPDATE IF NEEDED. BOTH THE GFS AND NAM MAINTAIN A SATURATED THERMAL PROFILE BELOW FREEZING AFTER MIDNIGHT TONIGHT ALONG THE RED RIVER. WE WILL INCREASE POPS INTO THE CHC CATEGORY FOR OUR NORTHERN TIER OF ZONES AND EXPAND SLT CHC SOUTHWARD TO JUST NORTH OF THE METROPLEX. LITTLE SNOW ACCUMULATION IS EXPECTED...BUT WILL LET DAYSHIFT REEVALUATE AND DETERMINE THE NEED FOR HEADLINES. WE EXPECT THE COLUMN TO QUICKLY DRY FROM THE TOP DOWN...RESULTING IN JUST A SLT CHC FOR FLURRIES AFTER SUNRISE ON FRIDAY OVER OUR NORTHERN ZONES. ATTM...PROFILES APPEAR TOO DRY ON SAT FOR ANY PRECIP AND HAVE REMOVED ISOLATED FLURRIES FROM THE GRIDS. PATTERN WISE...AMPLIFIED RIDGE MOVING ONTO THE PACIFIC COAST AND STRONG HUDSON BAY LOW WILL SET THE STAGE FOR SEVERAL SHOTS OF COLD AIR TO DROP DOWN INTO THE CENTRAL CONUS. SFC HIGH PRESSURE WILL SETTLE INTO NORTH TX ON FRIDAY. THE AREA CAN EXPECT BELOW NORMAL TEMPS...RANGING FROM THE MID 30S TO THE LOWER 50S. AS THE UPPER RIDGE AND TROUGH BOTH TRANSLATE A BIT FARTHER EAST...COLD HIGH PRESSURE SYSTEMS WILL SHOOT NORTHEAST OF OUR AREA...RESULTING IN MINIMAL INFLUENCE OVER OUR NORTHEASTERN ZONES. SOME RETURN FLOW AND BUILDING HEIGHTS SHOULD SET UP A SOUTHWEST TO NORTHEAST GRADIENT ON TEMPS SUN THROUGH TUES. DRY WEATHER IS EXPECTED THROUGH THE EXTENDED. JUST BEYOND THE SCOPE OF THIS FORECAST...ECMWF AND UKMET SUGGEST A STRONG SURFACE HIGH WILL PLUNGE INTO THE CENTRAL CONUS LATE NEXT WEEK AND PUSH ANOTHER COLD FRONT INTO NORTH TX. SCHULTZ && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 30 38 23 41 / 80 10 10 10 10 WACO, TX 51 36 45 27 47 / 90 10 10 10 10 PARIS, TX 40 27 35 22 39 / 100 30 10 10 10 DENTON, TX 40 29 36 23 40 / 80 20 10 10 10 MCKINNEY, TX 40 29 35 23 39 / 100 20 10 10 10 DALLAS, TX 41 31 38 24 42 / 90 10 10 10 10 TERRELL, TX 43 31 39 23 43 / 100 10 10 10 10 CORSICANA, TX 48 33 40 24 44 / 90 10 10 10 10 TEMPLE, TX 53 37 50 29 48 / 90 10 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21/05/92 tx AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE FORT WORTH TX 730 PM CST WED JAN 31 2007 .UPDATE... LARGE SCALE SUBSIDENCE BEHIND EXITING SHORT WAVE IS CURRENTLY IN PLACE OVER NORTH TEXAS. OTHER THAN A FEW SPRINKLES DEVELOPING LATE IN THE EVENING IT NOW APPEARS THAT ANY MEASURABLE RAIN WILL HOLD OFF OVER NORTH TEXAS UNTIL AFTER MIDNIGHT. THEREFORE...WE WILL LOWER POPS TO SLIGHT CHANCES THE REST OF THE EVENING...BUT KEEP HIGH RAIN CHANCES OVERNIGHT AND THURSDAY MORNING. THE COLD FRONT CONTINUES TO SURGE SOUTHWARD OVER WEST TEXAS BUT THE EASTERN PORTION OF THE FRONT IS STILL NORTH OF OKC. WE EXPECT THE FRONT TO MOVE THROUGH THE WESTERN PORTIONS OF NORTH TEXAS AFTER MIDNIGHT AND THROUGH THE REMAINDER OF THE REGION AFTER SUNRISE THURSDAY. AS OF NOW...LOW LEVEL TEMPERATURE PROFILES SUGGEST THAT ALL PRECIPITAION SHOULD FALL AS RAIN SO WE WILL LEAVE THE FORECAST AS SUCH. HOWEVER...WE WILL BE EXAMINING THE 00Z MODELS AS WELL AS SURFACE TRENDS CLOSELY THROUGH THE EVENING. OTHER THAN LOWERING THE EVENING POPS...WE WILL ADJUST CLOUD COVER...TEMPS...DEW POINTS AND WINDS BASED ON CURRENT TRENDS. 79. && .AVIATION... 520 PM CST SHORT TERM CLEARING AREAS HAS MOVED INTO THE DFW TRACON AREA WITH BOTH IR AND VIS SATELLITE IMAGERY SHOWING THE BACK EDGE NEAR A SPS-DFW-ACT LINE. LOOKING AT THE FORECAST TRENDS OVERNIGHT RUC AND GFS BOTH INDICATING RETURN MOISTURE FROM LOW LEVEL JET WITH THE LAYER FROM SURFACE TO 2K FEET NEARLY SATURATED BY 09Z SO EXPECT IFR CONDITIONS FOR AIRPORTS THURSDAY AM. WILL CONTINUE WITH LIGHT RAIN OR DRIZZLE DEVELOPING BETWEEN MIDNIGHT AND 300 AM THURSDAY MORNING AND CONTINUING THROUGH MOST OF THURSDAY. WIND SOUTH TO SOUTHEAST OVERNIGHT BECOMING MORE EASTERLY THURSDAY AM AND NORTHERLY THURSDAY AFTERNOON WITH WIND SPEED BETWEEN 6-10 KNOTS. 50 && .DISCUSSION... MUCH OF NORTH TEXAS IS EXPERIENCING A BRIEF BREAK IN PRECIP COURTEOUSY OF SUBSIDENCE BEHIND THE DEPARTING SHORTWAVE. LIGHT RETURNS OF MOSTLY RAIN CONTINUE ACROSS THE NORTHERN AND EASTERN ZONES. TEMPERATURES OUTSIDE OF THE PRECIP AREAS ARE NOW REACHING THE UPPER 30S TO MID 40S. THE NEXT SHORTWAVE TO AFFECT NORTH TEXAS LATER TONIGHT THROUGH TOMORROW IS NOW LOCATED NEAR BAJA. A WEAK COLD FRONT NOW BISECTING THE COUNTRY WILL MOVE INTO NORTH TEXAS TOMORROW. THIS FRONT WILL LIKELY SLOW DOWN AND BECOME SOMEWHAT ILL-DEFINED AS UPPER LEVEL ENERGY BECOMES STRUNG OUT IN STRONG FLOW ALOFT. PRECIP CHANCES THROUGH TOMORROW WILL BE THE BEST IN THE SOUTH AND EAST...WHERE FRONTOGENESIS WILL BE MAXIMIZED. EXPECT THIS ROUND OF PRECIP TO BE ALL LIQUID AS CLOUDS AND RAIN WILL KEEP TEMPERATURES ABOVE FREEZING...ALTHOUGH 18Z RUNS HAVE TRENDED SLIGHTLY COLDER THAN THE 12Z RUNS. IF THE COLD AIR ARRIVES EARLIER AND DEEPER THAN THE CURRENT THINKING...A WINTRY MIX MAY NEED TO BE INCLUDED IN THE NORTHERN ZONES. THE FRONT WILL REMAIN IN THE SOUTHERN CWA TOMORROW...EFFECTIVELY KEEPING THE COLDER AIR BOTTLED UP IN THE NORTHERN TWO-THIRDS OF THE CWA. THIS WILL CREATE QUITE A DIFFERENCE BETWEEN DIURNAL TEMPERATURES IN THE NORTH AND THE SOUTH. UPPER LEVEL PATTERN WILL BECOME MORE MERIDIONAL OVER THE NEXT FEW DAYS AS TALL RIDGING COMES ASHORE ON THE WEST COAST...PUSHING THE BROAD TROUGH FARTHER EAST. SHORTWAVE ENERGY WILL ROUND THE BASE OF THE UPPER LEVEL TROUGH AND SKIRT THE NORTHERN SECTIONS FRIDAY AND SATURDAY. IN ADDITION...A STRONG ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS ON FRIDAY. MOISTURE WILL BE LIMITED...AND HAVE ONLY INCLUDED A SLIGHT CHANCE IN THE NORTHERN ZONES. TEMPERATURE PROFILES WILL BE COLD ENOUGH IN THE CHILLY AIR BEHIND THE FRONT FOR PRECIP TO FALL AS A MIX OF RAIN AND SNOW. TEMPERATURES WILL BEGIN TO REBOUND SOMEWHAT BY SUNDAY. HOWEVER... THIS WILL BE TEMPERED BY A REINFORCING SHOT OF COLD AIR ON MONDAY. THE NEXT CHANCE OF RAIN LOOKS TO BE NEXT TUESDAY AS ISENTROPIC LIFT BECOMES ESTABLISHED ON THE 285K AND 290K PLANES. /13 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 37 46 31 41 26 / 70 50 10 10 10 WACO, TX 42 54 36 51 34 / 80 50 10 10 10 PARIS, TX 33 40 32 39 22 / 70 80 20 20 10 DENTON, TX 34 45 30 37 23 / 60 50 10 10 10 MCKINNEY, TX 37 44 31 38 24 / 70 70 10 10 10 DALLAS, TX 38 48 36 43 30 / 70 60 10 10 10 TERRELL, TX 37 47 33 42 30 / 80 80 10 10 10 CORSICANA, TX 38 51 35 46 31 / 80 80 10 10 10 TEMPLE, TX 41 56 38 56 34 / 80 50 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 42/13 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 322 PM CST WED JAN 31 2007 ...AVIATION SHORT TERM CLEARING AREAS HAS MOVED INTO THE DFW TRACON AREA WITH BOTH IR AND VIS SATELLITE IMAGERY SHOWING THE BACK EDGE NEAR A SPS-DFW-ACT LINE. LOOKING AT THE FORECAST TRENDS OVERNIGHT RUC AND GFS BOTH INDICATING RETURN MOISTURE FROM LOW LEVEL JET WITH THE LAYER FROM SURFACE TO 2K FEET NEARLY SATURATED BY 09Z SO EXPECT IFR CONDITIONS FOR AIRPORTS THURSDAY AM. WILL CONTINUE WITH LIGHT RAIN OR DRIZZLE DEVELOPING BETWEEN MIDNIGHT AND 300 AM THURSDAY MORNING AND CONTINUING THROUGH MOST OF THURSDAY. WIND SOUTH TO SOUTHEAST OVERNIGHT BECOMING MORE EASTERLY THURSDAY AM AND NORTHERLY THURSDAY AFTERNOON WITH WIND SPEED BETWEEN 6-10 KNOTS. 50 && .DISCUSSION... MUCH OF NORTH TEXAS IS EXPERIENCING A BRIEF BREAK IN PRECIP COURTEOUSY OF SUBSIDENCE BEHIND THE DEPARTING SHORTWAVE. LIGHT RETURNS OF MOSTLY RAIN CONTINUE ACROSS THE NORTHERN AND EASTERN ZONES. TEMPERATURES OUTSIDE OF THE PRECIP AREAS ARE NOW REACHING THE UPPER 30S TO MID 40S. THE NEXT SHORTWAVE TO AFFECT NORTH TEXAS LATER TONIGHT THROUGH TOMORROW IS NOW LOCATED NEAR BAJA. A WEAK COLD FRONT NOW BISECTING THE COUNTRY WILL MOVE INTO NORTH TEXAS TOMORROW. THIS FRONT WILL LIKELY SLOW DOWN AND BECOME SOMEWHAT ILL-DEFINED AS UPPER LEVEL ENERGY BECOMES STRUNG OUT IN STRONG FLOW ALOFT. PRECIP CHANCES THROUGH TOMORROW WILL BE THE BEST IN THE SOUTH AND EAST...WHERE FRONTOGENESIS WILL BE MAXIMIZED. EXPECT THIS ROUND OF PRECIP TO BE ALL LIQUID AS CLOUDS AND RAIN WILL KEEP TEMPERATURES ABOVE FREEZING...ALTHOUGH 18Z RUNS HAVE TRENDED SLIGHTLY COLDER THAN THE 12Z RUNS. IF THE COLD AIR ARRIVES EARLIER AND DEEPER THAN THE CURRENT THINKING...A WINTRY MIX MAY NEED TO BE INCLUDED IN THE NORTHERN ZONES. THE FRONT WILL REMAIN IN THE SOUTHERN CWA TOMORROW...EFFECTIVELY KEEPING THE COLDER AIR BOTTLED UP IN THE NORTHERN TWO-THIRDS OF THE CWA. THIS WILL CREATE QUITE A DIFFERENCE BETWEEN DIURNAL TEMPERATURES IN THE NORTH AND THE SOUTH. UPPER LEVEL PATTERN WILL BECOME MORE MERIDIONAL OVER THE NEXT FEW DAYS AS TALL RIDGING COMES ASHORE ON THE WEST COAST...PUSHING THE BROAD TROUGH FARTHER EAST. SHORTWAVE ENERGY WILL ROUND THE BASE OF THE UPPER LEVEL TROUGH AND SKIRT THE NORTHERN SECTIONS FRIDAY AND SATURDAY. IN ADDITION...A STRONG ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS ON FRIDAY. MOISTURE WILL BE LIMITED...AND HAVE ONLY INCLUDED A SLIGHT CHANCE IN THE NORTHERN ZONES. TEMPERATURE PROFILES WILL BE COLD ENOUGH IN THE CHILLY AIR BEHIND THE FRONT FOR PRECIP TO FALL AS A MIX OF RAIN AND SNOW. TEMPERATURES WILL BEGIN TO REBOUND SOMEWHAT BY SUNDAY. HOWEVER... THIS WILL BE TEMPERED BY A REINFORCING SHOT OF COLD AIR ON MONDAY. THE NEXT CHANCE OF RAIN LOOKS TO BE NEXT TUESDAY AS ISENTROPIC LIFT BECOMES ESTABLISHED ON THE 285K AND 290K PLANES. /13 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 37 46 31 41 26 / 70 50 10 10 10 WACO, TX 42 54 36 51 34 / 80 50 10 10 10 PARIS, TX 33 40 32 39 22 / 70 80 20 20 10 DENTON, TX 34 45 30 37 23 / 60 50 10 10 10 MCKINNEY, TX 37 44 31 38 24 / 70 70 10 10 10 DALLAS, TX 38 48 36 43 30 / 70 60 10 10 10 TERRELL, TX 37 47 33 42 30 / 80 80 10 10 10 CORSICANA, TX 38 51 35 46 31 / 80 80 10 10 10 TEMPLE, TX 41 56 38 56 34 / 80 50 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 42/13 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1100 AM CST THU FEB 1 2007 .UPDATE... UPDATED FORECAST FOR REMOVAL OF FLURRIES IN THE ERN CWA...AND DROP TEMPERATURES CWA-WIDE A FEW DEGREES GIVEN SUBZERO START...ESPECIALLY WESTERN CWA. 01.12Z RAOBS AND RUC 925MB TEMPS ANALYSIS SHOWING CORE OF COLDEST LOW LEVEL AIRMASS /-16C/ OVER CWA THROUGH THE MORNING HOURS...BEFORE SHIFTING EAST AND MODERATING THIS AFTERNOON. SHOULD SEE TEMPERATURES RESPOND A LITTLE MORE THAN THEY HAVE THUS FAR. STILL A FEW SITES IN RWIS/AWOS NETWORK BELOW ZERO AS OF 16Z ACROSS NERN IA AND SERN MN...SO EVEN A 10 DEGREE RISE LATE THIS MORNING INTO EARLY AFTERNOON WILL YIELD MAX TEMPS 2-4 DEGREES LOWER THAN PVS FORECASTED IN WRN CWA. HIGH CLOUDS WILL BEGIN TO STREAM INTO CWA THOUGH AFTERNOON...AHEAD OF DEEP LAYER SHORTWAVE TROUGH ROTATING OUT OF DAKOTAS/MN. ARCTIC FRONT ALIGNED FROM LAKE SUPERIOR/ALEXANDRIA MN/ABERDEEN SD AT 16Z...WITH PLETHORA OF -SN/FLURRIES ALONG/BEHIND FRONT. THIS TO MOVE THROUGH MOST CWA BY FRIDAY MORNING. CURRENT SHIFT IS CONTEMPLATING ISSUANCE OF ADVISORIES /EITHER WIND CHILL OR WINTER WEATHER/...DEPENDING ON WHETHER COMBINATION OF BLOWING SNOW/AREAS OF LIGHT SNOW WILL BE ENOUGH TO MENTION...OR WHETHER WIND CHILLS WILL EXCEED CRITERIA /-20F/. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ BINAU wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1100 AM CST THU FEB 1 2007 .UPDATE... UPDATED FORECAST FOR REMOVAL OF FLURRIES IN THE ERN CWA...AND DROP TEMPERATURES CWA-WIDE A FEW DEGREES GIVEN SUBZERO START...ESPECIALLY WESTERN CWA. 01.12Z RAOBS AND RUC 925MB TEMPS ANALYSIS SHOWING CORE OF COLDEST LOW LEVEL AIRMASS /-16C/ OVER CWA THROUGH THE MORNING HOURS...BEFORE SHIFTING EAST AND MODERATING THIS AFTERNOON. SHOULD SEE TEMPERATURES RESPOND A LITTLE MORE THAN THEY HAVE THUS FAR. STILL A FEW SITES IN RWIS/AWOS NETWORK BELOW ZERO AS OF 16Z ACROSS NERN IA AND SERN MN...SO EVEN A 10 DEGREE RISE LATE THIS MORNING INTO EARLY AFTERNOON WILL YIELD MAX TEMPS 2-4 DEGREES LOWER THAN PVS FORECASTED IN WRN CWA. HIGH CLOUDS WILL BEGIN TO STREAM INTO CWA THOUGH AFTERNOON...AHEAD OF DEEP LAYER SHORTWAVE TROUGH ROTATING OUT OF DAKOTAS/MN. ARCTIC FRONT ALIGNED FROM LAKE SUPERIOR/ALEXANDRIA MN/ABERDEEN SD AT 16Z...WITH PLETHORA OF -SN/FLURRIES ALONG/BEHIND FRONT. THIS TO MOVE THROUGH MOST CWA BY FRIDAY MORNING. CURRENT SHIFT IS CONTEMPLATING ISSUANCE OF ADVISORIES /EITHER WIND CHILL OR WINTER WEATHER/...DEPENDING ON WHETHER COMBINATION OF BLOWING SNOW/AREAS OF LIGHT SNOW WILL BE ENOUGH TO MENTION...OR WHETHER WIND CHILLS WILL EXCEED CRITERIA /-20F/. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ BINAU wi