AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 331 PM MST FRI JAN 12 2007 ...STRONG COLD FRONT WILL CONTINUE TO MOVE SLOWLY SOUTH ACROSS EASTERN UTAH AND WESTERN COLORADO... .SHORT-TERM (TONIGHT THROUGH SUNDAY): MAJOR WINTER STORM CONTINUES TO EVOLVE ACROSS WESTERN COLORADO AND EASTERN UTAH THIS AFTERNOON. DEEP AND MOIST SOUTHWEST FLOW ALOFT OUT AHEAD OF A STRONG LOW PRESSURE SYSTEM CENTERED OVER THE SOUTHERN GREAT BASIN WILL CONTINUE TO OVERRIDE COLDER AIR AT THE SFC...BRINGING WIDESPREAD PRECIPITATION TO THE REGION. VERY STRONG SFC COLD FRONT CONTINUES TO LAY NEARLY STATIONARY JUST NORTH OF THE INTERSTATE 70 CORRIDOR THIS AFTERNOON. SFC WNDS AT SEVERAL SITES ALONG INTERSTATE 70 HAVE SWUNG AROUND TO A MORE WESTERLY COMPONENT. LATEST RUC MODELS AGREES WITH THIS POSITIONING AND EXPECT THE FRONT TO START SLOWLY SAGGING SOUTH THROUGH THE FORECAST AREA THIS EVENING. IN ADDITION...LAPS SFC ANALYSIS PLACES A SFC LOW OVER THE GUNNISON VALLEY...WHICH WILL EVENTUALLY HELP DRAW THE COLDER AIRMASS SOUTHWARD THROUGH THE REMAINDER OF WESTERN COLORADO. AND THIS WL HELP TO DRIVE THE COLDER AIR SOUTH AND WEST THROUGH THE EASTERN UTAH VALLEYS AND DESERTS. AS A RESULT...AREAS OF RAIN WILL BE QUICKLY CHANGING OVER TO SNOW THIS EVENING OVER THE VALLEYS. WIDESPREAD ADVISORY TO WARNING SNOWFALL IS EXPECTED ACROSS THE ENTIRE FORECAST AREA TONIGHT AND SATURDAY...AS THE CONVEYOR BELT OF WARM MOIST AIR CONTS TO WORK NORTHEAST ACROSS THE REGION THANKS TO THE SLOW EVOLUTION OF THE MAIN UPPER LEVEL LOW. CONDITIONS START TO IMPROVE FROM WEST TO EAST SATURDAY EVENING AS THE MAIN UPPER LEVEL LOW FILLS AND LIFTS ENE. LEFT IN ITS WAKE WILL BE THE COLDEST AIRMASS OF THE SEASON WITH MOST AREAS DROPPING TO SUB- ZERO READING BY SUNDAY MORNING. COLD DAY ON SUNDAY WITH SNOW SHOWERS CONFINED TO THE DIVIDE REGION IN COLD NLY FLOW ALOFT. DAYTIME HIGHS VARY FROM THE SINGLE DIGITS TO LOW 20S ACROSS THE FORECAST AREA. .LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)... MODELS SHOW GOOD AGREEMENT THROUGH TUE AS LINGERING ENERGY AT THE BOTTOM OF THE TROUGH RETROGRADES INTO THE DESERT SOUTHWEST AND HIGH PRESSURE BUILDS OVER THE THE PACIFIC NORTHWEST. BY SUN NIGHT REMAINING SHOWERS FROM THE PRESENT SYSTEM WILL BE CONFINED TO THE MOUNTAINS NEAR THE CONTINENTAL DIVIDE...WITH A FEW OROGRAPHIC SHOWERS CONTINUING INTO MON. COLD TEMPS WILL BE THE MAIN FORECAST PROBLEM. THE COLD AIR MASS AND FRESH SNOW WILL RESULT IN VERY COLD TEMPS AS THE SKIES CLEAR EARLY MON AND TUE...WITH STRONG VALLEY INVERSIONS SETTING UP. MUCH OF THE AREA WILL SEE LOWS BELOW ZERO. THE FLOW BECOMES NORTHEAST TO EAST BY TUE KEEPING US DRY AND COLD. THEN...MODEL AGREEMENT FALLS APART BY WED AS THE MORE PROGRESSIVE ECMWF SHOWS ANOTHER LOW MOVING ONSHORE OVER WA...AND FLOW BECOMING SOUTHWEST OVER THE FORECAST AREA. THE GFS ON THE OTHER HAND KEEPS BLOCKING HIGH PRESSURE OVER THE NORTHWEST CONUS AND NORTHWEST FLOW OVER US. BOTH SOLUTIONS KEEP US DRY THROUGH THU...WITH A WETTER SOLUTION ON FRI WITH THE EC. FOR NOW WILL KEEP THE DRIER PERSISTENT FORECAST THROUGH THE PERIOD. TEMPS WILL GRADUALLY MODIFY...ESPECIALLY ON SLOPES AND THE HIGHER ELEVATIONS. INVERSIONS WILL HOLD FAST OVER MOST VALLEY AREAS. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...HEAVY SNOW WARNING THROUGH SATURDAY MORNING FOR ZONES 1/2. WINTER STORM WARNING THROUGH SATURDAY FOR ZONES 3/9/12/13/17/18/19/23. SNOW AND BLOWING SNOW ADVISORY THROUGH SATURDAY FOR ZONES 4/10. SNOW ADVISORY THROUGH SATURDAY FOR ZONES 5/6/7/8/11/14/20/21/22. .UT...WINTER STORM WARNING THROUGH SATURDAY MORNING FOR ZONE 23/25. HEAVY SNOW WARNING THROUGH SATURDAY MORNING FOR ZONE 24. SNOW AND BLOWING SNOW ADVISORY THROUGH SATURDAY FOR ZONE 28. SNOW ADVISORY TONIGHT THROUGH SATURDAY MORNING FOR ZONE 22/27/29. $$ JDC/EH co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 422 PM EST FRI JAN 12 2007 .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...PRETTY MUCH STATUS QUO AS THE SFC MAP IS CONCERNED WITH HIGH PRES CNTRD TO OUR NE OVER THE WRN ATLC WITH RIDGING EXTENDING ACROSS MUCH OF THE SERN CONUS. MEANWHILE...A COASTAL TROUGH REMAINS IN PLACE OFF THE SC/GA COASTS. STRATOCU ASSCD WITH THE TROUGH HAS HAD A HARD TIME MAKING IT ONSHORE AND TEMPS THIS AFTN HAVE SOARED INTO THE MID 70S ACROSS MUCH OF THE AREA. SHUD SEE THE TROUGH DISSIPATE TONIGHT AS THE SFC HIGH MOVES FARTHER E. SKIES WILL END UP BEING PCLDY AND WITH LGT WINDS...CUD SEE SOME PATCHY FOG BUT NOT ENOUGH TO INCLUDE IN THE FCST ATTM. LOWS WILL RANGE FROM THE UPPER 40S INLAND TO MID 50S ALONG THE COAST. OUTSIDE OF A DECENT CU FIELD AND SOME HIGH CLOUDS...XPCT ENOUGH SUN TOMORROW TO ALLOW TEMPS TO CLIMB INTO THE MID 70S...A GOOD 15 DEG ABOVE NORMAL. A MILD S TO SW FLOW TOMORROW NIGHT WILL KEEP TEMPS A DEG OR TWO WARMER THAN TONIGHT...RANGING FROM AROUND 50 DEG INLAND TO THE UPPER 50S ALONG THE COAST...STILL ABOUT 15 DEG ABOVE NORMAL. && .LONG TERM /SUNDAY THROUGH FRIDAY/...STRONG RIDGING BOTH SURFACE AND ALOFT WILL CONTINUE ACROSS THE AREA SUN INTO MON...THEN WILL GIVE WAY TO NEXT UPSTREAM COLD FRONT TUE. UNSEASONABLY WARM CONDITIONS TO PREVAIL ACROSS THE CWFA AHEAD OF THE FRONT EARLY IN THE WEEK...WITH POSSIBLE 80 DEGREE TEMPS NOT OUT OF THE QUESTION ACROSS A FEW SECTIONS OF THE SRN CWFA. A LARGE TEMP GRADIENT TO PREVAIL BOTH AFTNS...WITH COOLING SEA BREEZE INFLUENCES. WILL KEEP WATCH ON POSSIBLE COASTAL SHRA WITH STRENGTHENING AND DEEPENING S-SW FLOW SUN NIGHT/MON...BUT FOR NOW FEEL THAT STEERING FLOW WILL KEEP ANY SHRA OVER THE ATLC. POPS WILL THEN INCREASE INTO THE CHANCE RANGE ON TUE WITH THE FRONTAL PASSAGE. FRONT WILL SLOWLY MOVE SE OF THE AREA TUE NIGHT/WED...AND WILL LIKELY STALL ACROSS THE SW ATLC AND FL...AS HIGH PRES SLOWLY BUILDS FROM THE N AND W. HOWEVER...OVERRUNNING OF MOISTURE BEHIND THE FRONT AND ISENTROPIC LIFTING WILL RESULT IN PLENTY OF CLOUDS AND LINGERING RAINS DURING THE MIDDLE OF THE WEEK. AT THIS POINT THERE IS AT LEAST A SMALL CHANCE THAT THE COLDER AIR MAY RESULT IN SOMETHING OTHER THAN RAIN ACROSS SOME OF THE NRN MOST AREAS...BUT THERE IS WAY TOO MUCH UNCERTAINTY AT THIS TIME TO GO WITH ANYTHING OTHER THAN RAIN IN THE FCST. EVEN SO...COMBINATION OF CLOUD COVER AND CAA WILL HOLD TEMPS ON WED DOWN IN THE 40S OR LOWER 50S MOST AREAS. DRIER AND EVEN COLDER WX TO MOVE IN LATE IN THE WEEK...WITH POSSIBLE FREEZING TEMPS THU AND FRI MORNING ACROSS INLAND AREAS. && .MARINE...A COASTAL TROUGH LINGERS OFF THE SC/GA COASTS THIS AFTN BUT SHUD FINALLY BEGIN TO BREAK DOWN TONIGHT AS THE SFC HIGH TO THE N AND E SHIFTS FARTHER E. WILL HAVE E TO NE WINDS THE FIRST HALF OF THE NIGHT OVER THE NEARSHORE WATERS...VEERING TO E/SE LATE...MORE IN LINE WITH THE RUC WHICH HAS HAD THE BEST HANDLE ON THIS FEATURE. THE SCA FOR THE OUTER GA WATERS IS STILL AN ISSUE AS SEAS HAVE BEEN 4-5 FT AT THE R2 TOWER TDA. THE WNA GUIDANCE SHOWS SEAS BUILDING TO 5 FT AT 41008 TONIGHT BUT CANNOT BUY INTO THIS SINCE IT IS BASED ON THE SLIGHTLY STRONGER WINDS OF THE GFS. PREFER TO CANCEL THE SCA WITH THE AFTN PACKAGE AND REPLACE IT WITH A SCSEC HEADLINE INSTEAD. MAY SEE SOME 6 FT SEAS COME BACK INTO THE PICTURE TOMORROW NIGHT AS A MORE SOLID SLY FLOW BECOMES ESTABLISHED BUT WILL NOT BE RAISING THAT HEADLINE ATTM. OTHERWISE...WINDS XPCTD TO REMAIN AOB HEADLINE CRITERIA THROUGH SAT NIGHT. ATLC RIDGING ACROSS THE AREA SUN AND EARLY MON WILL SHIFT SE AND GIVE WAY TO AN APPROACHING COLD FRONT MON NIGHT/EARLY TUE. THE FRONT WILL SLOWLY MOVE THRU THE AREA DURING TUE AS STRONG HIGH PRES BUILDS FROM THE NW AND N. THE COMBINATION OF CAA AND PINCHED GRADIENT WILL LIKELY RESULT IN AT LEAST SCA HEADLINES IN WAKE OF THE FRONT TUE NIGHT/WED. DEPENDING UPON IF WINDS ARE MORE N OR NE DURING THIS TIME WILL HELP DETERMINE HOW HIGH SEAS WILL REACH...AND I MAY HAVE GONE A LITTLE CONSERVATIVE GIVEN SOME UNCERTAINTY IN THE EXACT FETCH. EVEN SO...SEAS WILL BUILD TO AT LEAST 5 OR 6 FT WITHIN 20 NM OF THE COAST...AND UP TO 8 OR 9 FT FURTHER OFFSHORE. LOCAL SEA BREEZE INFLUENCES WILL BACK WINDS TO SE OR S NEAR THE COAST SUN AND MON AFTN. && .AVIATION /18Z-18Z/...CONDITIONS XPCTD TO BE VFR THROUGH THE PERIOD. MAY SEE SOME PATCHY FOG TONIGHT BUT AT THIS POINT FELT CHANCES WERE TOO LOW TO MENTION. && .CHS WATCHES/WARNING ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ RJB/33 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1005 AM EST FRI JAN 12 2007 .SHORT TERM /THIS AFTERNOON/...HIGH PRES CNTRD OVER THE WRN ATLC JUST E OF THE NC OUTER BANKS THIS MORNING WITH A COASTAL TROUGH HANGING TOUGH OVER THE SC/GA COASTAL WATERS. EARLY VIS SAT IMAGERY INDICATES SOME HIGH CLOUDS STREAMING E OVER THE AREA AND PLENTY OF STRATOCU OFF THE COAST TRYING TO WORK WWD. WITH A DECENT CU FIELD XPCTD THIS AFTN...THINK THERE WILL BE MORE CLOUDS THAN NOT THROUGH THE DAY...SO PARTLY SUNNY SKY COVER SHUD COVER IT. PLAN TO REMOVE THE SLGT CHC POPS FOR OUR NRN SC COUNTIES AS WE PREFER TO JUST MENTION ISO SHOWERS. HIGHS WILL TOP OUT AROUND 70 DEG AWAY FROM THE COAST...WITH TEMPS REMAINING IN THE MID TO UPPER 60S AT THE COAST DUE TO THE ONSHORE FLOW. ONLY MINOR TWEAKS TO THE GRIDS AND ZFP NEEDED. UPDATED ZFP OUT SHORTLY. && .MARINE...PREFER TO FOLLOW THE RUC DEPICTION OF THE COASTAL TROUGH AS THE GFS AND WRF CONTINUE TO INITIALIZE POORLY. THE LATEST OBS INDICATE WINDS AOB 15 KT WITH SEAS AOB 5 FT...HIGHEST OVER THE OUTER GA WATERS. TOUGH CALL ON THE SCA FOR AMZ374 AS SEAS HAVE BEEN FLIP-FLOPPING AROUND ADVISORY CRITERIA FOR A WHILE AND WILL LIKELY CONTINUE TO DO SO THROUGH THE AFTN WITH THE PESKY COASTAL TROUGH IN PLACE. WILL CONTINUE THE THINKING OF KEEPING SOLID NE WINDS GOING FOR THE MORNING ACROSS THE NEARSHORE WATERS...THEN GRADUALLY VEER WINDS E/SE THROUGH THE AFTN. E TO SE WINDS WILL PREVAIL ACROSS THE GA OFFSHORE WATERS TDA WITH THE COASTAL TROUGH HOLDING JUST W OF AMZ374. SEAS WILL GENERALLY REMAIN IN THE 3-4 FT RANGE ACROSS THE NEARSHORE WATERS TDA WITH 4-6 FT IN THE OUTER GA WATERS. OVERALL...NO MAJOR CHANGES NEEDED TO THE CWF WITH THE MID-MORNING UPDATE. && .AVIATION /12Z-12Z/...CONDITIONS XPCTD TO BE VFR THROUGH THE PERIOD ALTHO BKN CIGS ARE A GOOD BET ON/OFF THROUGH THE DAY...ESPCLY AT KCHS. && .CHS WATCHES/WARNING ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM FOR AMZ374. && $$ RJB ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 310 AM EST FRI JAN 12 2007 .SHORT TERM /TODAY THROUGH SUNDAY/...COASTAL TROF HANGING STRONG OFF THE CHS CWFA SHORE THIS MRNG AS EVIDENCED BY CONVERGING STREAMLINES ON MSAS ANALYSIS AND BUOYS WITH SE WINDS WHILE SHORELINE OBS ARE NE. TROF WILL HAVE A BIT OF A STRUGGLE LIFTING N AND AWAY FROM THE AREA THIS MRNG WITH STRONG HIGH PRES OFF THE MID ATLC COAST...AND THIS WILL HELP KEEP A FAIRLY DECENT MIDLVL CLOUD DECK IN PLACE THRU MOST OF THE DAY. ALTHOUGH IR SAT IMAGERY SHOWS MOCLR SKIES FOR INLAND SITES WHICH MATCH SFC OBS...CLOUD COVER OVER THE COASTAL WATERS WILL SLOWLY SPREAD INLAND AND COMBINE WITH LATE MRNG/EARLY AFTN CU DEVELOPMENT TO KEEP AT LEAST PTLY CLOUDY SKIES IN PLACE. THE ONLY SHOT AT PRECIP TDA WILL BE ALONG THE BEAUFORT-COLLETON-CHARLESTON COAST WHERE DEEPER MOISTURE AND MODEST LIFT WITHIN THE TROF ALONG WITH A SPOT VORTICITY MAXIMA WILL CONVERGE TDA. IF ANY PRECIP OCCURS IT WILL BE RATHER LIGHT...BUT JUST ENOUGH TO INCLUDE 20 POPS FOR ALONG THE COAST. DESPITE THE ANTICIPATED THICKER CLOUD COVER... SW TO W UPR FLOW TO THE W OF THE CWFA AND AN UPR LEVEL RIDGE AXIS OVER THE AREA WILL ALLOW THE WARMING TREND TO CONTINUE...FORCING MAX TEMPS TO ARND 70 DEGREES. SKIES WILL REMAIN GENERALLY PARTLY CLOUDY TNGT INTO SAT AS THE TROF APPEARS TO MORE DISSIPATE RATHER THAN LIFT NWD. LACK OF GOOD CONVERGENCE AND LESS MOISTURE IN THE 1000-500MB COLUMN SHOULD PREVENT SHOWER DEVELOPMENT OVERNIGHT AND TOMORROW SO WILL KEEP THE FCST DRY. TEMPS WILL REMAIN MILD TNGT AND TMRW WITH THE UPR LVL RIDGE AXIS SHIFTING EWD AND DEEPER SWLY FLOW TAKING HOLD. MIN TEMPS TNGT WILL DROP TO ARND 50 DEGREES WITH MAX TEMPS ON SAT RISING TO THE MID 70S. SIMILAR STORY SAT NIGHT INTO SUN WITH THE RIDGE AXIS MOVING FURTHER INTO THE ATLC WITH SFC HIGH PRES CENTERED WELL IN THE ATLC EXTENDING WWD OVER THE SE CONUS COAST. TEMPS WILL CONTINUE TO RISE SLIGHTLY... REACHING THE MID 50S FOR MIN TEMPS SAT NIGHT WITH MAX TEMPS ON SUN RISING INTO THE UPR 70S...MAKING 80 DEGREE READINGS NOT OUT OF THE QUESTION. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...MODELS STILL LOOK ON TRACK FOR A LOW PRES CENTER TO MOVE FROM THE SRN PLAINS INTO THE OH VLY SUN AND SUN NIGHT...WITH A TRAILING CDFNT TO MOVE ACRS TX AND INTO THE LWR MISS VLY. THIS FNT WILL DRAG ACRS THE GULF COAST STATES MON AND MON NIGHT...THEN SLOWLY MOVE ACRS THE SE STATES TUE AND TUE NIGHT. STILL SOME MINOR TIMING ISSUES ASSOCIATED WITH THIS SYSTEM... SO WILL LEAVE POPS CAPPED IN THE CHC CATEGORY. THE FNT THEN LOOKS TO STALL JUST S AND E OF THE AREA WED AND WED NIGHT WHICH MAY KEEP CLOUDS AND PRECIP IN THE AREA A BIT LONGER THAN ANTICIPATED. A SECONDARY CDFNT WILL THEN SWING THRU THE AREA THU WHICH WILL BRING A NOTICEABLY COOLER AIRMASS TO THE AREA FOR THE END OF THE WEEK. WITH TIMING ISSUES MAKING CONFIDENCE RATHER LOW...HAVE LEFT THE EXTENDED PORTION ALONE AND WILL LET A FULL MODEL AND HPC SLATE DURING DAY SHIFT DETERMINE THE OUTCOME OF THE EXTENDED. && .MARINE...A SHARP COASTAL TROF REMAINS PINNED ACROSS THE NEARSHORE WTRS THIS MRNG. THE 12/08Z OBSERVATIONS SUGGEST THE TROF AXIS EXTENDED FROM SAINT SIMMONS TO ABT 20 NM E OF THE CHARLESTON HARBOR ENTRANCE TO PSN OFF THE SE NC COAST. THE GFS/NAM BOTH INITIALIZED THE STRENGTH AND LOCATION OF THE COASTAL TROF POORLY AND ARE STILL WAY TOO QUICK IN MOVING IT INLAND TDA AS HIGH PRES SHIFTS FARTHER OFF THE MID-ATLC COAST. ONLY THE 12/03Z RUC SEEMS TO HAVE A GOOD HANDLE ON THE MESO-SCALE SITUATION AND WL BE CLOSELY FOLLOWED FOR THE NXT 6 HRS OR SO. PLAN TO KEEP SOLID NE WNDS GOING FOR MUCH OF THE MRNG ACROSS THE NEARSHORE WTRS THEN GRADUALLY VEER WNDS E/SE THROUGH THE AFTN. IT IS WORTH NOTING THAT THERE IS A REAL POSSIBILITY THAT WNDS MAY REMAIN NE WELL INTO THE AFTN ESP ACROSS THE SC WTRS UNTIL THE COASTAL TROF BECOMES OVERWHELMED BY THE INCRG SLY SYNOPTIC FLOW AND DISSIPATES. SE WNDS WL PREVAIL ACROSS THE GA OFFSHORE WTRS TDA WITH THE COASTAL TROF HOLDING JUST W OF AMZ374. THE PRES GRADIENT REMAINS PINCHED ALONG CHARLESTON COUNTY COAST THIS MRNG WHERE WNDS ARE SOLIDLY 15 KT WITH OCNL GUSTS TO 20 KT PER CARO-COOP AND C-MAN OBSERVATIONS. XPCT WNDS TO SLOWLY DIMINISH THROUGH THE MRNG BUT WL NEED TO BREAK OFF THE WTRS N OF EDISTO BEACH TO INITIALIZE SLGTLY HIGHER WNDS. SEAS WL GENERALLY REMAIN IN THE 3-4 FT RANGE ACROSS THE NEARSHORE WTRS TDA BUT WL HOLD IN THE 4-6 RANGE IN THE GA OFFSHORE WTRS WHERE A SMALL CRAFT ADVISORY WL BE MAINTAINED INTO THE AFTN. SLY WNDS WL PREVAIL FOR THE REMAINDER OF THE FCST PERIOD WITH THE MARINE AREA REMAINING ON THE WRN FRINGES OF ATLC HIGH PRES. A CDFNT IS FCST TO PUSH THROUGH THE WTRS ERLY NXT WEEK. && .AVIATION /06Z-06Z/...AN EXTENSIVE AMOUNT OF STRATOCU MOVING INLAND FROM THE ATLC WL IMPACT KCHS AND KSAV FOR MUCH OF THE MRNG. DESPITE THIS CIGS SHOULD REMAIN ABOVE MVFR THRESHOLDS...HOLDING AROUND 4000-5000 FT. MAY SEE SOME OF THE STRATOCU SCATTER OUT LTR THIS MRNG. WE MAY NEED TO REEVALUATE THIS WITH THE 12Z TAF CYCLE AS SOME OF THE SHORT TERM GUIDANCE SUGGESTS CIGS MAY HOLD WELL INTO THE AFTN ESP AT KCHS. && .CHS WATCHES/WARNING ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM FOR AMZ374. && $$ JPC/ST ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 940 PM EST FRI JAN 12 2007 .UPDATE... AT 02Z...A COLD FRONT WAS LOCATED FROM SRN ONTARIO...FAR SE MICHIGAN...THEN IT EXTENDED SW INTO NE...CNTRL...AND SW INDIANA. THE FRONT WILL CONTINUE TO SAG THROUGH THE REMAINDER OF THE FCST AREA OVERNIGHT. UPR LVL DIVERGENCE IN ASSOCIATION WITH WEAK WX DISTURBANCES AND UPR LVL JET DYNAMICS WILL TEAM UP WITH ISENTROPIC LIFT/OVERRUNNING OVER THE AFOREMENTIONED FRONTAL BOUNDARY TONIGHT. HENCE...PCPN WILL BE WIDESPREAD FOR MOST OF THE REGION. LATEST RUC SOUNDINGS SUGGEST THAT SOME SLEET MAY MIX IN ACRS THE NRN AND NWRN CWFA LATE TONIGHT AS COLDER AIR IN THE LOW LVLS SLOWLY FILTERS SOUTHEAST. HAVE MADE SOME MINOR ADJUSTMENTS TO THE ZONES/GRIDS. BELIEVE CHC/S FOR SNOW ARE SLIM TONIGHT BASED ON LATEST MODEL SOUNDINGS...SO HAVE REMOVED SNOW AND HAVE GONE WITH JUST A CHC OF SLEET. HAVE ALSO MODIFIED OVERNIGHT LOWS A TAD...WHICH WILL RANGE FROM THE LOWER 30S N AND NW TO THE UPPER 30S SOUTHEAST. TEMPERATURES WILL FALL TO AROUND 32 DEGREES IN THE N AND NW BY SATURDAY MORNING. HAVE OPTED TO LEAVE OUT FREEZING RAIN CHC/S DUE TO THE BORDERLINE VALUE. THERE COULD BE A CHC OF FREEZING RAIN EARLY ON SATURDAY IF TEMPS DIP TO 31 DEGREES BRIEFLY. MIDNIGHT SHIFT SHOULD HAVE A BETTER HANDLE ON THIS POSSIBILITY AS THEY WATCH HOW FAR TEMPERATURES DROP OVERNIGHT. && .PREV DISCUSSION... SHORT TERM... BETWEEN TONIGHT AND TOMORROW THE BEST CHANCE FOR PRECIPITATION IS TONIGHT. THE SURFACE TROUGH IS IN THE AREA THROUGH TONIGHT AND WILL BE PULLING AWAY SOME FROM THE CWA TOMORROW. EVEN TOMORROW THE MORNING HOURS HAVE A BETTER CHANCE THAN THE AFTERNOON HOURS DO. WITH THE TROUGH SLIDING THROUGH THE SOUTHEASTERN HALF OF THE CWA THIS EVENING AND JUST TO OUR EAST AND SOUTHEAST TONIGHT...THIS WILL GIVE THE SOUTHERN PART OF THE CWA A BETTER CHANCE FOR PRECIP THAN THE NORTHERN PART. ALSO THIS WILL CAUSE TEMPERATURE PROFILES TO BE COLDER IN THE NORTHERN PART THAN IN THE SOUTHERN PART AND MORE SO NEAR THE SURFACE. THEREFORE AS TONIGHT WEARS ON FROM NORTH TO SOUTH...A MIX OF PRECIP HAS A CHANCE TO FORM. A LITTLE TRICKY TO SEE IF SURFACE TEMPERATURES ARE GOING TO GET COLD ENOUGH TONIGHT FOR FREEZING RAIN TO COME INTO THE MIX IN OUR NORTHERN COUNTIES...BUT DIDN`T LOOK LIKE A BIG ENOUGH CHANCE TO MENTION IN THE FORECAST. IF SURFACE TEMPERATURES START DROPPING OFF MORE THAN EXPECTED AND THE SURFACE TROUGH MOVES FURTHER EAST AND SOUTH THAN EXPECTED...THEN SOME LIGHT FREEZING RAIN IS POSSIBLE FOR LATE TONIGHT INTO TOMORROW FOR OUR NORTHERN PART. BUT THERE IS SOME UNCERTAINTY IN HOW MUCH COLD AIR IS GOING TO PENETRATE INTO THE NORTHERN HALF OF THE CWA. ANY FREEZING OR FROZEN TYPE PRECIP TO FALL TONIGHT OR TOMORROW IS NOT EXPECTED TO AMOUNT TO AS MUCH AS THE SYSTEM NEXT WEEK IS LOOKING. LEFT TEMPERATURES ALONE FOR THE MOST PART EXCEPT TO DROP THE NORTH BY A DEGREE FOR TOMORROW. LONG TERM... CDFNT DROPPING SE INTO THE AREA THIS AFTN WILL STALL OVER THE OH RVR VALLEY ON SAT. DEEP TROF OVER WRN U.S. WILL CONT WSW-SW FLOW ALOFT OVER OUR AREA. WK DISTURBANCES MOVG NE AHEAD OF THE MAIN TROF WILL RESULT IN ONCL BACKING OF WINDS ALOFT AND ENHANCED OVER-RUNNING POTENTIAL. TIMING OF THESE WK SHRTWV`S IS HARD TO PIN DOWN AT THIS JUNCTURE AS MODELS NOT SURPRISINGLY ARE IN CONSIDERABLE DISAGREEMENT ON A COUPLE OF SUCH WAVES SAT NGT AND SUND. THUS, LEFT POPS FOR SAT NGT IN CHC CATEGORY FOR NOW AND CONTD WITH LOW QPF. OVERLAYING MSP SOUNDING WITH MODEL SOUNDINGS INDICATES ALL MODELS INITIALIZED THE ARCTIC AIRMASS TOO WARM BELOW 950MB AND NOT QUITE WARM ENOUGH WITH THE WARM LAYER ALOFT AROUND 700MB. THUS, HEDGED TOWARD A LITTLE WARMER AIR ALOFT AND COLDER AIR NEAR THE SFC FOR PTYPE AND MIN/MAX CONSIDERATIONS THIS WEEKEND. SGFNT PRECIP FROM THIS SCENARIO IS EXPECTED SUN AFTN-EVE AS STRONG TROF LIFTS ENE ACROSS CENTRAL PLAINS ENHANCING OVER-RUNNING OF SFC BOUNDARY. LEANED TOWARD GFS TIMING WHICH IS FASTER THAN NAM. STILL A GOOD POTENTIAL FOR FREEZING RAIN IN OUR AREA WITH THIS PATTERN. HELD OFF ON WATCH FOR NOW SINCE SGFNT PRECIP EXPECTED TO BEGIN LATE IN 4TH PD AT THE EARLIEST. HWVR, THERE IS POTENTIAL THAT WEAKER SHRTWV`S MOVG THROUGH THE AREA COULD NECESSITATE AN ADVISORY SOONER. NAM/GFS CONSISTENT INDICATING DRY SLOT WILL PUNCH INTO THE AREA LATE SUNDAY NGT BRINGING SGFNT PRECIP TO AN END WITH DEFORMATION ZONE PRECIP STAYING TO THE NORTH OF THE CWA. NORMALLY THIS IS NOT A SCENARIO FAVORABLE FOR HEAVY SNOW, BUT WITH VERY MOIST AMS (700MB MIXING RATIO AROUND 4G/KG SUN EVE) OVER-RUNNING THE ARCTIC BOUNDARY, CAN`T RULE THIS OUT. SOME LINGERING LIGHT SNOW PSBL MONDAY AS UPPER TROF SHEARS OUT ACROSS THE GRTLKS. GOING CHC OF LAKE EFFECT SNOW SHOWERS CONTINUES FOR MON NGT-TUE NGT AS INSTABILITY EXPECTED TO BECOME EXTREME, HWVR, INVERSION HEIGHTS AT THIS POINT LOOK RATHER LOW FOR SGFNT LAKE EFFECT SNOW. RIDGE EXPECTED TO MOVE ACROSS THE AREA WED WITH ANOTHER FRONT APPROACHING ON THU. THIS SHOULD BE A DRY PD BUT WITH PASSAGE OF THE CDFNT WILL BRING A RENEWED CHC OF LAKE EFFECT SNOW SHOWERS ALONG WITH COLDER TEMPS AGAIN FRI. AVIATION... AT 23Z...A COLD FRONT EXTENDED FROM SRN ONTARIO...SE LOWER MICHIGAN...THROUGH NW INDIANA...THEN SW INTO THE MID MS RIVER VLY. THIS FRONT WILL GRADUALLY SAG SE THROUGH THE REGION OVERNIGHT...BEING LOCATED FROM WRN NY...SRN OHIO AND SRN INDIANA BY 12Z SATURDAY. LOCAL AND SURROUNDING RADARS CONTINUE TO SHOW A FAIRLY WIDESPREAD AREA OF PCPN ACRS ILLINOIS...INDIANA AND OHIO. ISENTROPIC LIFT...AS SEEN ON THE 295 K SFC...WILL CONTINUE OVERNIGHT...RESULTING IN OVER RUNNING PCPN ACRS THE FCST AREA. ALSO...A FEW WEAK EMBEDDED WX DISTURBANCES ALONG WITH SOME UPR DIVERGENCE FROM A ANTICYCLONICALLY CURVED UPR LVL JET WILL ALSO ENHANCE THE PCPN POTENTIAL. SHALLOW...COLDER AIR WILL WORK INTO NW INDIANA OVERNIGHT TO BRING A THREAT OF SOME SLEET...AND HAVE KEPT THIS IN THE KSBN TAF ATTM. FOR KFWA...PCPN SHOULD REMAIN IN THE LIQUID FORM...THEN TAPER OFF TOWARD 12Z. IFR CONDITIONS CAN BE EXPECTED THROUGH AT LEAST 12Z. THEN...A RESPITE IN THE WIDESPREAD PCPN IS EXPECTED ON SATURDAY...WHICH WILL ALLOW VSBYS AND CIGS TO IMPROVE SLIGHTLY. ANOTHER EMBEDDED DISTURBANCE IN THE SW FLOW ALOFT...ALONG WITH A RETURN OF ISENTROPIC LIFT/WAA...WILL BRING A THREAT FOR WINTRY PCPN TO THE TAF SITES AFTER 00Z SUNDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 3 PM EST SATURDAY FOR LMZ043-LMZ046. && $$ UPDATE/AVIATION...HICKMAN SHORT TERM...98 LONG TERM....01 in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 443 AM EST THU JAN 11 2007 .SHORT TERM... TODAY AND TONIGHT. PRIMARY FOCUS ON LOW LEVEL GULF MOISTURE TRANSPORT INTO SOUTHERN GREAT LAKES BY END OF SHORT TERM PERIOD. AT 09Z PLUME OF HIR SFC DPS FM ERN TX NOSING INTO ERN KS. WAVE EMBEDDED IN ML WSWRLY FLOW TO AID IN STRONG LEE SIDE CYCLOGENESIS TO FURTHER STRENGTHEN MOISTURE TRANSPORT TODAY. AS WAVE MOVES EWD INTO MS VALLEY TONIGHT AND STRONG SFC-8H FLOW VEERS MOISTURE AXIS TO SHIFT INTO CWA. WL SEE SFC DPS TO SHOW DRAMATIC RISE OF UP TO 20F HIR IN ABOUT 24HRS ADN CPDS LOWER TO NEAR ZERO AFTR 06Z. PRECIP TO BECOME MORE WIDESPREAD LATE TONIGHT IN INCREASINGLY CONFLUENT LOW LEVEL FLOW. HOWEVER...STRONGEST I295 PRES ADVECTION WILL BE EAST OF CWA WITH LOW LEVEL JET AFTER SUB CLOUD LAYER SATURATES...SO ANTICIPATE PRECIP TO BE MORE ON THE LIGHT SIDE WITH LESS FORCING...AND HAVE CUT QPF A BIT. WITH NAM AND GFS SHOWING GOOD OVERALL SIGNALS AND HIGH MOS POPS HOWEVER WILL UP POPS AFT MIDNIGHT TO LOW END CATAGORICAL. LITTLE CHANGE IN TEMPS TODAY. SHOULD SEE AT LEAST G35 MPH THIS AFTERNOON WHEN GREATEST 1000-950MB LAPSE RATES REALIZE BEST MOMENTUM XFER. SHOULD TEMPS TREND WARMER EVEN HIR GUSTS INTO LOW END ADVISORY RANGE COULD BE REALIZED. WITH CLOUD COVER/PRECIP AND WELL MIXED BL TONIGHT HAVE RAISED TEMPS A FEW DEGREES. && .LONG TERM... FRIDAY THROUGH WEDNESDAY PICTURE NOT A WHOLE LOT CLEARER FOR MUCH OF THE LONG TERM PERIOD THAN LAST NIGHT. RAIN IS EXPECTED TO CONTINUE INTO FRIDAY AS FIRST LOW MOVES ACROSS THE AREA WITH A COLD FRONT BEGINNING ITS SE MVMT ACROSS THE AREA SOMETIME FRI NGT OR SATURDAY. HAVE NOT INCREASED TO CAT POPS ANYWHERE ON FRI AS OF YET AS TRENDS HAVE BEGAN TO TAKE MUCH OF THE HIGHER PRECIP AMOUNTS AND COVERAGE TO THE SOUTH OF THE AREA. STILL APPEARS TO BE ENOUGH LIGHTER PRECIP AROUND TO MAINTAIN HIGH LIKELY POPS ALL AREAS ON FRIDAY AND EXTEND LIKELY POPS INTO FRI EVE IN SE AREAS. COLDER AIR WILL START TO FILTER IN LATE FRI NGT INTO SATURDAY. THIS AND AMOUNT OF REMAINING MSTR WILL LEAD TO A TRICKY SCENARIO IN TERMS OF PRECIP TYPE AND COVERAGE. NAM THERMAL FIELDS WOULD SUGGEST THAT ANY PRECIP WOULD REMAIN IN THE FORM OF RAIN...BUT WITH SFC TEMPS NEAR FREEZING COULD END UP FREEZING. THE GFS PROFILES SUGGEST MAINLY SNOW AS 850 MB TEMPS DROP TO AROUND -5 TO -7 C BY SAT AFTERNOON. THIS UNCERTANTITY HAS PLAGUED THE FORECAST FOR THE PAST FEW DAYS NOW AND APPEARS NO CLEARER NOW. MIX PRECIP WAS DROPPED A FEW DAYS AGO AND LOOK LIKE WILL BE FORCED TO THROW THIS BACK IN NW AREA LATE FRI NGT AND NW HALF OF SO ON SAT WITH JUST RAIN SE. FINAL SURGE OF WARMER AIR BEGINS SAT NGT INTO SUNDAY IN ADVANCE OF PESKY UPPER LOW OVER THE SW US BEGINNING TO EJECT AS ANOTHER WAVE AND 120+KT JET STREAK GIVE IT A KICK OUT. HOW MUCH MSTR AND WARM AIR ARRIVES FOR SUNDAY WILL BE KEY IN PCPN CHANCES AS WELL AS TYPE. THINK LIGHT PRECIP WILL ONCE AGAIN MATERIALIZE OVER MUCH OF THE CWA BY SUNDAY WITH HIGHEST CHC POPS REMAINING THERE. HOWEVER...DRIER AIR MASS AND SLOWER KICK OUT OF SYSTEM MAY PRECLUDE ARRIVAL OF PRECIP UNTIL LATE SUNDAY OR SUNDAY NIGHT. IT IS SUNDAY NIGHT AND MONDAY THAT MAY END UP THE MOST FAVORABLE PERIOD FOR SIGNIFICANT PRECIP WHICH COULD BE IN THE FORM OF SNOW OR ICE ESPECIALLY ACROSS NW HALF OF CWA. TRACK OF SFC LOW GENERALLY OVER OR SE OF THE CWA WITH MAIN CONSENSUS TRACKING ACROSS EASTERN OHIO ON MONDAY. ANY DEVIATION IN THIS WILL DRASTICALLY AFFECT THE ANTICIPATED LOCATION OF THE HEAVIEST PRECIP. PAST SEVERAL MODELS RUNS HAVE PLACED THE HEAVIEST SNOW FROM N ILLINOIS INTO PARTS OF CNTRL/NORTHERN LWR MI. HOWEVER...TRENDS STILL SUGGESTING THAT A BUFFER ZONE OF A MIXED BAG OF PRECIP COULD SET UP SOUTH OF THIS BAND WHICH WOULD INCLUDE PARTS OF THE CWA. MANY QUESTIONS REMAIN TO BE ANSWERED SO STAY TUNED TO LATER FORECASTS. BLAST OF ARCTIC AIR STILL ARRIVING BY MON NGT/TUES WITH TEMPS HEADING BELOW NORMAL FOR THE FIRST TIME IN SEVERAL WEEKS. ANY SNOW COVER COULD PLAY HAVOC WITH TEMPS AS WELL...ESPECIALLY AT NIGHT. WITH COLDER AIR OVER THE GREAT LAKES...LAKE EFFECT SNOW WILL LIKELY OCCUR BUT INTENSITY AND COVERAGE REMAIN TRICKY AS EITHER NW OR N FLOW COULD SET UP OVER LK MI NEXT WEEK. WILL LEAVE GRIDS ALONE FOR THIS TIME FRAME. && .AVIATION... VFR XPCD THROUGH THE PD. VIGOROUS LEAD SHORTWAVE IN SRN SK...WITH ASSOCD STRONG SFC LOW IN MN...SPLITTING AWAY FROM MAIN ENERGY IN NW WA. LLJ DEVELOPING ACROSS NRN IL AND WILL CONTINUE TO MOV EWD AS JET AXIS VEERS SLIGHTLY EARLLY THIS AM. SECOND GATE KIWX VWP TO 47 KTS IN SRN SK WITH STRONG SFC LOW IN MN...SECONDARY ENERGY/WAVE SPLITTING OFF INTO NW WA. THOUGH SOME MINOR SFC GUSTS POSBL THIS AM...CLEARLY SUFFICIENT DECOUPLING HAS OCCURRED ACRS NRN IN PER 05 UTC SFC ANALYSIS...WARRANTING CONTINUED MENTION OF LLWS AT BOTH SITES. HAVE FURTHER INCREASED WS020 WIND SPEED TO 60KTS AT KSBN PER KLOT VWP/WOLCOTT PROFILER/NAM12/RUC POINT SNDGS. GREATER MIXING BY MID/LATE MORNING AND BY AFTERNOON WIND GUST/MOMENTUM XFER POTENTIAL FOR AT LEAST G32 KTS. RAFL TO ARRIVE BEYOND 06 UTC AND WILL PROVIDE TIMING DETAILS WITH 12 UTC ISSUANCE...THOUGH AT LEAST MVFR BY 12 UTC FRI ANTICIPATED. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST FRIDAY FOR LMZ043-LMZ046. && $$ SHORT TERM/AVIATION...MURPHY LONG TERM...FISHER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 105 AM EST THU JAN 11 2007 .AVIATION... VFR XPCD THROUGH THE PD. VIGOROUS LEAD SHORTWAVE IN SRN SK...WITH ASSOCD STRONG SFC LOW IN MN...SPLITTING AWAY FROM MAIN ENERGY IN NW WA. LLJ DEVELOPING ACROSS NRN IL AND WILL CONTINUE TO MOV EWD AS JET AXIS VEERS SLIGHTLY EARLLY THIS AM. SECOND GATE KIWX VWP TO 47 KTS IN SRN SK WITH STRONG SFC LOW IN MN...SECONDARY ENERGY/WAVE SPLITTING OFF INTO NW WA. THOUGH SOME MINOR SFC GUSTS POSBL THIS AM...CLEARLY SUFFICIENT DECOUPLING HAS OCCURRED ACRS NRN IN PER 05 UTC SFC ANALYSIS...WARRANTING CONTINUED MENTION OF LLWS AT BOTH SITES. HAVE FURTHER INCREASED WS020 WIND SPEED TO 60KTS AT KSBN PER KLOT VWP/WOLCOTT PROFILER/NAM12/RUC POINT SNDGS. GREATER MIXING BY MID/LATE MORNING AND BY AFTERNOON WIND GUST/MOMENTUM XFER POTENTIAL FOR AT LEAST G32 KTS. RAFL TO ARRIVE BEYOND 06 UTC AND WILL PROVIDE TIMING DETAILS WITH 12 UTC ISSUANCE...THOUGH AT LEAST MVFR BY 12 UTC FRI ANTICIPATED. && .SHORT TERM... TONIGHT AND AND THURSDAY... LATEST SFC ANALYSIS SHOWS RIDGE EXTENDING UP FROM TN/OH VALLEY INTO EASTERN GREAT LAKES. VIS SAT SHOWING BAND OF MID-LEVEL CLOUDS AHEAD OF WARM FRONT ON BACK SIDE OF SFC HIGH MOVING THROUGH THE AREA ATTM. BACK EDGE OF CLOUDS PUSHING THROUGH WESTERN ILLINOIS AND EXPECTING CLEARING IN OUR AREA LATER THIS EVENING AS WARM FRONT LIFTS QUICKLY NORTHWARD. SFC HIGH SLIDES EAST BRINGING STRONGER GRADIENT OVER THE AREA TONIGHT. DESPITE SOME POSSIBLE DECOUPLING EARLY ON...ESPECIALLY IN EASTERN CWA...NOT LOOKING FOR MUCH IN THE WAY OF DIURNAL COOLING AS CLOUD COVER EARLY EVENING AND WAA AFTER MIDNIGHT SHOULD WORK TO LIMIT RADIATIONAL COOLING TONIGHT AND KEEP TEMPS NEAR GUIDANCE. LOOK FOR A DECENT AMOUNT OF SUNSHINE EARLY ON TOMORROW BEFORE CLOUDS ARE ON THE INCREASE ONCE AGAIN BY AFTERNOON. MORNING SUN SHOULD SET THE STAGE FOR GUSTY WINDS WITH 15-20KT SUSTAINED AND MIXING DOWN GUSTS TO 30KT. GOOD WAA WILL SEE NEARLY A 10C JUMP IN 850MB TEMPS FROM NOW TO THURSDAY AFTERNOON. UPSTREAM TEMPS THAT WERE NOT AFFECTED BY MID CLOUDS GENERALLY IN THE MID-UPPER 40S WITH SOME 50S FURTHER BACK IN W/SW MO SO WILL BLEND MET/MAV GUIDANCE AND GO AROUND 45 NE AND NEAR 50 SW. && .LONG TERM... SIMILAR SCENARIO BETWEEN THE GFS AND NAM-WRF FOR TOMORROW NIGHT...BUT A DIFFERENCE LIES WITHIN THE RAIN CHANCES BETWEEN THE TWO. GFS OF COURSE IS SHOWING HIGHER CHANCE/MUCH MORE QPF THAN THE NAM-WRF IS...BUT WITH HIGH GUIDANCE POPS FOR TOMORROW NIGHT...ESPECIALLY AFTER MIDNIGHT...AND PAST FEW MODEL RUNS SHOWING THE SURFACE TROUGH IN THE AREA...HAVE INCREASED RAIN CHANCES FOR TOMORROW NIGHT. BY 12Z FRIDAY THE SURFACE TROUGH WILL BE JUST TO THE WEST OF OUR CWA. THIS TROUGH IS THEN PROGGED TO MOVE INTO THE CWA ON FRIDAY...RAIN CHANCES FOR THIS TIME MAY LIKELY HAVE TO BE INCREASED BUT KEPT LIKELY CHANCES FOR THE TIME BEING. THEN FRIDAY NIGHT THE TROUGH BEGINS TO MOVE EAST OF THE CWA...DECREASING THE RAIN CHANCES. ANY PRECIP ON SATURDAY COULD TAKE ON A DIFFERENT FORM...BUT THIS FAR OUT DID NOT WANT TO TRY AND GET CUTE WITH PRECIP TYPES AND WHERE AT. MODEL SOUNDINGS ARE SHOWING THE SATURDAY TIME FRAME TO BE AROUND THE FREEZING MARK...SOME EVEN LATE FRIDAY NIGHT...KEEPING WHAT FORM THE PRECIP WILL TAKE TRICKY. THEREFORE WILL NOT CHANGE THE TYPE OF PRECIP FOR SATURDAY THROUGH SATURDAY NIGHT THAT IS IN THE FORECAST BUT DID MODIFY POPS A LITTLE TO SHOW A LESSER PRECIP CHANCE FOR SATURDAY AND SATURDAY NIGHT THAN FRIDAY NIGHT AND SUNDAY. THEN THERE HAVE BEEN SOME MODEL TIMING CHANGES/DIFFERENCES FOR THE LOW TO EJECT OUT OF THE SOUTH CENTRAL UNITED STATES FOR NEXT WEEK. SO NO CHANGES FOR NEXT WEEK...BUT IS LOOKING LIKE SUNDAY HAS A GOOD CHANCE TO BE WET WITH A WEAK LOW MOVING NORTHEASTWARD UP THE SURFACE TROUGH TO OUR SOUTHEAST...THEN ANOTHER LOW TO SOUTHEASTERN MISSOURI/SOUTHERN ILLINOIS BY SUNDAY EVENING. BY MONDAY MORNING THE LOW IS CURRENTLY PROGGED TO BE OVER NORTHWESTERN OHIO AND THEN ON TO THE NORTHEAST DURING MONDAY. DID NOT CHANGE THE PRECIP TYPE FOR SUNDAY NIGHT YET EVEN THOUGH ITS LOOKING LIKE THE REAL COLD AIR PUSH INTO THE CWA WILL NOT BE UNTIL THE DAYTIME MONDAY...NOT LOOKING COLD ENOUGH IN THE TEMPERATURE PROFILE FOR ALL SNOW UNTIL MONDAY. THEN DECENT FETCH DOWN LAKE MICHIGAN MONDAY NIGHT FOR LAKE EFFECT SNOW TO TAKE SHAPE. THE LAKE EFFECT SNOW CHANCES THEN LOOK LIKE THEY COULD CONTINUE THROUGH TUESDAY NIGHT. THEN WITH THE HIGH PRESSURE MOVING IN ON WEDNESDAY AND CHANGING THE WIND DIRECTION TO THE SOUTHWEST...THE LAKE EFFECT SNOW WILL END. BUT LIKE MENTIONED ABOVE...THERE HAVE BEEN TIMING CHANGES IN THE MODELS FOR NEXT WEEK SO MADE NO CHANGES FOR THEN FOR NOW. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY THROUGH 7 PM EST THURSDAY FOR LMZ043-LMZ046. && $$ AVIATION...MURPHY SHORT TERM...LOGSDON LONG TERM....LOTHAMER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 330 AM CST FRI JAN 12 2007 .SYNOPSIS... ARCTIC BOUNDARY NOW THROUGH STATE AS OF 03Z WITH STRONG PUSH OF COLD AIR INTO THE NORTHERN PLAINS. MILD AIR IN THE 50S CONTINUES SOUTH OF THE FRONT WITH SUBZERO TEMPS GENERALLY ALONG AND NORTH OF I94 IN THE DAKOTAS. STRONG ARCTIC HIGH BUILDING INTO EASTERN MT ATTM WITH GREATEST PRESSURE RISES JUST BEHIND BOUNDARY IN EASTERN NEBRASKA AND KANSAS. IA REMAINS SHROUDED IN LOW STRATUS EXCEPT FOR THE FAR NW COUNTIES ATTM. A FEW FLURRIES REPORTED OVER SOUTHWEST SECTIONS TOO. UPPER AIR ANALYSIS SHOWS SECONDARY FRONTAL FEATURE OVER NORTHERN MN ALONG LEADING EDGE OF DEEPEST COLD AIR. ONLY SLIGHT REFLECTION CURRENTLY SEEN AT SFC. MAIN CHALLENGE TONIGHT WILL BE THE EXTENT OF SOUTHWARD MOVEMENT OF THE LOW STRATUS. CURRENT 11-3MU SHOWS SOME SOUTHWARD DRIFT BUT NOT MUCH. LARGER SCALE WATER VAPOR IMAGERY STILL SHOWS WESTERN TROUGH DIGGING SOUTH WITH MULTIPLE WAVES AT THE BASE OF THE TROUGH THOUGH SOME WEAKENING OF ENERGY ONGOING ATTM. .SHORT TERM (TODAY...SUN NIGHT)...MODELS IN SOME AGREEMENT TODAY TO BEGIN BREAKING UP CLOUDS AS WE HEAD INTO THE MORNING TO AFTERNOON HOURS. NAM12 AND RUC MODELS ARE MORE ADAMANT ABOUT HOLDING ONTO THE CLOUD COVER WHILE NAM/GFS PREFER TO BREAK THINGS UP A BIT. CLOUD TRENDS SUPPORT SOME PC SKIES LATER THIS MORNING THOUGH MOS GUIDANCE STILL HOLDS ONTO CLOUD COVER. INCREASING WINDS ALOFT WITH APPROACHING JET MAXES WILL LIKELY INCREASE HIGH LEVEL CLOUDS LATER IN THE AFTERNOON/EVENING EVEN IF BREAKS OCCUR THROUGH EARLY AFTERNOON. BEFORE THE MAIN UPPER TROUGH EJECTS NORTHEAST LATE SUNDAY INTO EARLY MONDAY THERE WILL LIKELY BE A FEW MINOR RIPPLES IN THE FLOW. MODELS ATTEMPTING TO RESOLVE THEM WITH SOME DIFFICULTY BUT THE GFS PICKS UP ON ONE OVERNIGHT TNT INTO EARLY SATURDAY MORNING. SOUNDINGS SHOW A BRIEF PERIOD OF LIFT WITH FLURRIES OR OR LIGHT FREEZING DRIZZLE POSSIBLE TNT WITH NAM SOUNDINGS DRYING OUT FASTER THAN THE GFS SOUNDINGS. WITH MAIN WAVE NOW COMING INTO PLAY LATER IN DAY ON SUNDAY...AM HOLDING OFF ON GREATER QPF AND SNOWFALL FOR THAT PERIOD AS QG FORCING ARRIVES TOWARD EVENING. AS UPPER LEVEL TROUGH LIFTS OVER THE STATE...DEFORMATION ZONE FORMS ON BACK SIDE OF SYSTEM WHICH SHOULD HELP PROLONG SNOWFALL INTO THE NIGHT AND EARLY MONDAY. BLOWING SNOW STILL APPEARS TO BE A PROBLEM WITH COLD TEMPS AND LIGHTER FLUFFY VARIETY EXPECTED. CURRENTLY EURO/GFS AND GEM SEEM TO HAVE THE BETTER HANDLE ON THE TIMING AND STRENGTH OF THE LOW. PROBLEM REMAINS THE AMT OF QPF WITH THE SYSTEM WHICH VARIES FROM ABOUT A HALF INCH WITH THE GFS TO NEARLY THREE QUARTERS WITH THE GEM. WITH TEMPS IN THE TEENS THROUGH THE BEST PERIOD OF SNOWFALL...HIGH SNOW TO WATER RATIOS EVEN .30 TO .40 WILL PROVIDE FOR AMTS OVER 6 INCHES. WITH UNCERTAINTY AS TO DETAILS OF PATH AND QPF...DONT FEEL CONFIDENT ISSUING A WATCH YET...BUT IF THE NEXT 2 RUNS CONFIRM THE PRESENT TRENDS...WATCH WILL PROBABLY BE NECESSARY LATER SUNDAY INTO THE NIGHT HOURS. SNOW CONTINUES INTO MONDAY MORNING WITH SOME BLOWING. .EXTENDED (MON...THUR)...COLD WEATHER TO FOLLOW WITH LITTLE IF ANY WARM UP UNTIL MID WEEK. MODELS HINT AT ANOTHER ARCTIC SHOT BY THE END OF THE OUTLOOK PERIOD. CERTAINLY THE COLDEST TEMPS IN QUITE SOME TIME WITH OVERNIGHT LOWS NEAR TO BELOW ZERO MON NIGHT/TUES NIGHT OVER SNOW COVERED AREAS ESPECIALLY. OF COURSE...ALL DEPENDS ON DEPTH OF SNOWPACK AND STORM THIS WEEKEND. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE && $$ REV ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 900 PM CST THU JAN 11 2007 .DISCUSSION... CONUNDRUM THIS EVE CENTERS AROUND FRZG DRZL POTENTIAL AND FATE OF CURRENT ADVY. LG WV TROUGH SETTLING INTO WRN CONUS WITH BROAD SWLY FLOW AHEAD INTO PLAINS. 120+KT JET SEGMENT NOTED FROM KS INTO UPPER OH RIVER VALLEY WITH LARGE PCPN SHIELD ON LEADING EDGE. SHRT WV WITH THIS FEATURE ADVANCING THROUGH MID/UPR MS VALLEY INTO GREAT LAKES PUSHING DEEPER MOISTURE OFF TO THE E. LITTLE DEEP UVM OR QG FORCING NOTED OVER IA...ALTHOUGH THERE IS SOME TO OUR N AS SHRT WV EJECTS OUT OF NRN PORTION OF TROUGH. SOME H85/H7 FN CONVERGENCE BUT MOISTURE NOT SUFFICIENT FOR RESPONSE. LGT RAIN/DRZL THAT APPEARS TO BE DIMINISHING IN RADAR TRENDS LOOKS TO BE DRIVEN BY THETA-E ADVECTION AND UVM IN SATURATED H9/H8 LAYER. 02Z SFC ANLYS PLACES CDFNT ACROSS SERN IA WITH SVRL EMBEDDED WVS. CANNOT REALLY PICK OUT A PRIMARY ONE...BUT LATEST RUC PUSHES ALL THESE LOW LEVEL MECHANISMS OFF TO THE EAST WITH 925MB TROUGH BY 06Z. HOWEVER RUC ALSO LINGERS THIS SATURATED LAYER ALONG AND S OF I80 THROUGH 06Z AND LINES UP WITH ECHOES TO OUR W. OAX REPORTS FLURRIES/FRZG DRZL HAVING MINIMAL EFFECT EVEN IN COLDER AIR THUS WILL KEEP MENTION OF PATCHY FRZG DRZL OR FLURRIES GOING WHERE APPROPRIATE AS IT MOVES FROM W TO E...BUT DROP HEADLINE. DO NOT EXPECT CONDITIONS THAT WOULD BE IMPLIED BY FRZG RAIN ADVY AND FRZG DRZL ADVY IS NO LONGER A VALID HEADLINE. BETTER LIKELIHOOD MAY EVEN BE FARTHER N INTO COLDER AIR OUTSIDE OF CURRENT HEADLINE...BUT NOT SUBSTANTIAL ENOUGH TO WARRANT NEW ONE. WET ROADS MAY START FREEZING FROM EXISTING MOISTURE TOO AS COLD ADVECTION CONTINUES. IEM FREEZE APP HAS SUB-FRZG ROAD TEMPS ALG AND NW OF ADAIR-BOONE-IOWA FALLS LINE AND SLOWLY ADVANCING SE. WILL HIT HARD IN NOWCASTS THAT SLICK SPOTS MAY DEVELOP...BUT LIKELY NOT AGGRAVATED MUCH BY ADDITIONAL MOISTURE. ALSO DROPPED HOURLY TEMP/DEWPOINTS TO SUPPORT MORE AGGRESSIVE COLD/DRY ADVECTION. 02Z SFC ANLYS ALSO SHOWED WIDESPREAD SIGNIFICANT PRES RISES BEHIND CFP. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1133 AM CST FRI JAN 12 2007 .UPDATE... COLD AIR HAS REALLY SURGED INTO KANSAS OVERNIGHT...AND CONTINUES ITS SOUTHEASTWARD PROGRESS DURING THE DAY TODAY. LOWEST 3000FT OR SO OF THE SOUNDINGS IN SOUTH CENTRAL KANSAS ARE BELOW -6.6C...THE CRITICAL TEMPERATURE AND DEPTH TO BE ABLE TO GET SNOW CRYSTALS DESPITE THE WARM AIR ALOFT. THEREFORE...WITH THE TEMPERATURES EXPECTED TO REMAIN NEARLY STEADY OR FALL A FEW MORE DEGREES...EXPECT THE PRECIPITATION TYPE IN THIS REGION TO REMAIN SNOW. FURTHER SOUTHEAST...WITH SLIGHTLY WARMER TEMPERATURES EXPECT MORE OF A MIXTURE OF FREEZING RAIN AND SLEET...AND MAYBE SOME SNOW MIXED IN AT TIMES. MADE THESE CHANGES IN THE FORECAST AND LOWERED TEMPERATURES TO COME MORE IN LINE WITH THE QUICKER ARCTIC AIR INTRUSION. SCHRECK && .PREV DISCUSSION... /ISSUED 321 AM CST FRI JAN 12 2007/ DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE PRECIPITATION TYPE DURING THE NEXT 48 HOURS AND HOW MUCH ACCUMULATION WILL TAKE PLACE. TODAY: LATEST SURFACE ANALYSIS SHOWING THE COLD ARCTIC AIR CONTINUING TO PLUNGE ITS WAY THROUGH THE FORECAST AREA. TEMPERATURES HAVE NOW DROPPED WELL INTO THE TEENS ACROSS CENTRAL KANSAS WITH TEMPERATURES FLIRTING WITH THE FREEZING MARK IN SOUTHEAST KANSAS. THESE TEMPERATURES WILL CONTINUE TO TUMBLE AS THE MORNING WEARS ON. THE NEXT CONCERN IS SOME PRECIPITATION TRYING TO DEVELOP ACROSS SOUTHERN OKLAHOMA. THIS IS ASSOCIATED WITH A WEAK UPPER LEVEL WAVE MOVING THROUGH THAT REGION WHICH IS DISPLAYED ON THE 305K THETA SURFACE. THIS AREA OF LIFT WILL LIFT NORTHEAST INTO SOUTHEAST KANSAS BY MID MORNING WHICH COULD BRING SOME ICY CONDITIONS TO AREAS MAINLY EAST OF THE KANSAS TURNPIKE. QPF AMOUNTS ARE QUESTIONABLE AT THIS POINT...BUT I WOULD NOT SURPRISED IF SOME FOLKS SEE A TENTH TO TWO TENTHS OF AN INCH OF RAIN...BUT IT WILL TAKE A LITTLE FOR THE GROUND TEMPERATURES TO COOL OFF BEFORE ANY SIGNIFICANT ICING HAPPENS. THE NAM-WRF SOLUTION IS EVEN SHOWING SOME LIFT DEVELOP DURING THE AFTERNOON ACROSS EASTERN OKLAHOMA WHICH COULD BRING ANOTHER ROUND OF PRECIPITATION. RIGHT NOW...THIS LOOKS LIKE A FREEZING RAIN SITUATION DUE TO SUCH WARM AIR ALOFT. AT FIRST GLANCE...WE FELT CONFIDENT ENOUGH TO REMOVE THE WINTER WEATHER ADVISORY FOR PORTIONS OF SOUTH CENTRAL KANSAS. HOWEVER...BASED ON THE LATEST RUC/NAM-WRF SOLUTIONS THEY ARE ADVERTISING THE LOW LEVEL FLOW BACKING WHICH WILL INCREASE THE ISENTROPIC LIFT DURING THE AFTERNOON. WE WILL GO AHEAD AND MENTION A FREEZING RAIN ADVISORY FOR AREAS ALONG AND EAST OF THE TURNPIKE WHILE AREAS WEST OF THE TURNPIKE WE WILL KEEP THE WINTER WEATHER ADVISORY GOING THROUGH 00Z. TONIGHT: WE ARE PLANNING ON KEEPING THE WINTER STORM WATCH GOING FOR NOW SINCE THERE IS SO MUCH UNCERTAINTY IN THE PERTURBATIONS IN SOUTHWEST FLOW ALOFT. THE NAM IS PICKING UP ON ANOTHER WAVE MOVING THROUGH THE FORECAST AREA TONIGHT WHILE THE GFS/UKMET ARE NOT SHOWING MUCH SUPPORT IN THIS. WE ARE GOING TO PLAY IT SAFE FOR NOW SINCE THERE IS SO MUCH UNCERTAINTY IN THE UPPER LEVEL PATTERN. IF ANYTHING DOES DEVELOP THEN WE COULD SEE MORE MIXED PRECIPITATION DEVELOPING MAINLY IN CENTRAL KANSAS DUE TO COLDER AIR ALOFT WITH MORE FREEZING RAIN AND DRIZZLE DEVELOPING ELSEWHERE. SATURDAY-SUNDAY: LATEST WATER VAPOR LOOP IS SHOWING THE UPPER LEVEL TROF CONTINUING TO DIG. THE LATEST GFS AND UKMET ARE TENDING TO SLOW DOWN THE POSITION OF THIS TROF TOWARDS SUNDAY. THIS WILL TEND TO FAVOR MORE IN THE WAY OF FREEZING RAIN WITH PERIODS OF SLEET ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS THROUGH SUNDAY. CENTRAL KANSAS COULD STILL SEE SOME SNOW ON SUNDAY...BUT AMOUNTS ARE STILL TOO DIFFICULT TO TELL AT THIS JUNCTURE. MONDAY-TUESDAY: THIS UPPER LEVEL TROF IS EXPECTED TO SETTLE OVER OUR AREA DURING THESE TWO DAYS WHICH WILL KEEP THINGS UNSEASONABLY COLD BUT DRY. COX && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 16 9 22 19 / 70 60 70 80 HUTCHINSON 13 8 20 16 / 50 60 70 80 NEWTON 14 8 21 19 / 60 60 70 80 ELDORADO 17 10 22 18 / 80 60 70 80 WINFIELD-KWLD 20 12 25 20 / 90 60 70 80 RUSSELL 11 6 14 11 / 10 60 70 80 GREAT BEND 11 6 16 13 / 10 60 70 80 SALINA 12 7 16 15 / 20 60 70 80 MCPHERSON 13 8 18 16 / 50 60 70 80 COFFEYVILLE 23 14 26 23 / 100 60 70 80 CHANUTE 19 11 25 21 / 100 60 70 80 IOLA 18 11 25 21 / 100 60 70 80 PARSONS-KPPF 21 12 26 22 / 100 60 70 80 && .ICT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST THIS AFTERNOON FOR KSZ071-072- 095-096-098>100. WINTER STORM WATCH FROM 6 PM CST THIS EVENING THROUGH SUNDAY AFTERNOON FOR KSZ032-033-047>053-067>072-082-083-091>096-098>100. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ051- 052-067-068-082-083-091-092. FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ053- 069-070-093-094. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 321 AM CST FRI JAN 12 2007 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE PRECIPITATION TYPE DURING THE NEXT 48 HOURS AND HOW MUCH ACCUMULATION WILL TAKE PLACE. TODAY: LATEST SURFACE ANALYSIS SHOWING THE COLD ARCTIC AIR CONTINUING TO PLUNGE ITS WAY THROUGH THE FORECAST AREA. TEMPERATURES HAVE NOW DROPPED WELL INTO THE TEENS ACROSS CENTRAL KANSAS WITH TEMPERATURES FLIRTING WITH THE FREEZING MARK IN SOUTHEAST KANSAS. THESE TEMPERATURES WILL CONTINUE TO TUMBLE AS THE MORNING WEARS ON. THE NEXT CONCERN IS SOME PRECIPITATION TRYING TO DEVELOP ACROSS SOUTHERN OKLAHOMA. THIS IS ASSOCIATED WITH A WEAK UPPER LEVEL WAVE MOVING THROUGH THAT REGION WHICH IS DISPLAYED ON THE 305K THETA SURFACE. THIS AREA OF LIFT WILL LIFT NORTHEAST INTO SOUTHEAST KANSAS BY MID MORNING WHICH COULD BRING SOME ICY CONDITIONS TO AREAS MAINLY EAST OF THE KANSAS TURNPIKE. QPF AMOUNTS ARE QUESTIONABLE AT THIS POINT...BUT I WOULD NOT SURPRISED IF SOME FOLKS SEE A TENTH TO TWO TENTHS OF AN INCH OF RAIN...BUT IT WILL TAKE A LITTLE FOR THE GROUND TEMPERATURES TO COOL OFF BEFORE ANY SIGNIFICANT ICING HAPPENS. THE NAM-WRF SOLUTION IS EVEN SHOWING SOME LIFT DEVELOP DURING THE AFTERNOON ACROSS EASTERN OKLAHOMA WHICH COULD BRING ANOTHER ROUND OF PRECIPITATION. RIGHT NOW...THIS LOOKS LIKE A FREEZING RAIN SITUATION DUE TO SUCH WARM AIR ALOFT. AT FIRST GLANCE...WE FELT CONFIDENT ENOUGH TO REMOVE THE WINTER WEATHER ADVISORY FOR PORTIONS OF SOUTH CENTRAL KANSAS. HOWEVER...BASED ON THE LATEST RUC/NAM-WRF SOLUTIONS THEY ARE ADVERTISING THE LOW LEVEL FLOW BACKING WHICH WILL INCREASE THE ISENTROPIC LIFT DURING THE AFTERNOON. WE WILL GO AHEAD AND MENTION A FREEZING RAIN ADVISORY FOR AREAS ALONG AND EAST OF THE TURNPIKE WHILE AREAS WEST OF THE TURNPIKE WE WILL KEEP THE WINTER WEATHER ADVISORY GOING THROUGH 00Z. TONIGHT: WE ARE PLANNING ON KEEPING THE WINTER STORM WATCH GOING FOR NOW SINCE THERE IS SO MUCH UNCERTAINTY IN THE PERTURBATIONS IN SOUTHWEST FLOW ALOFT. THE NAM IS PICKING UP ON ANOTHER WAVE MOVING THROUGH THE FORECAST AREA TONIGHT WHILE THE GFS/UKMET ARE NOT SHOWING MUCH SUPPORT IN THIS. WE ARE GOING TO PLAY IT SAFE FOR NOW SINCE THERE IS SO MUCH UNCERTAINTY IN THE UPPER LEVEL PATTERN. IF ANYTHING DOES DEVELOP THEN WE COULD SEE MORE MIXED PRECIPITATION DEVELOPING MAINLY IN CENTRAL KANSAS DUE TO COLDER AIR ALOFT WITH MORE FREEZING RAIN AND DRIZZLE DEVELOPING ELSEWHERE. SATURDAY-SUNDAY: LATEST WATER VAPOR LOOP IS SHOWING THE UPPER LEVEL TROF CONTINUING TO DIG. THE LATEST GFS AND UKMET ARE TENDING TO SLOW DOWN THE POSITION OF THIS TROF TOWARDS SUNDAY. THIS WILL TEND TO FAVOR MORE IN THE WAY OF FREEZING RAIN WITH PERIODS OF SLEET ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS THROUGH SUNDAY. CENTRAL KANSAS COULD STILL SEE SOME SNOW ON SUNDAY...BUT AMOUNTS ARE STILL TOO DIFFICULT TO TELL AT THIS JUNCTURE. MONDAY-TUESDAY: THIS UPPER LEVEL TROF IS EXPECTED TO SETTLE OVER OUR AREA DURING THESE TWO DAYS WHICH WILL KEEP THINGS UNSEASONABLY COLD BUT DRY. COX && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 22 15 22 19 / 30 60 70 80 HUTCHINSON 19 14 20 16 / 30 60 70 80 NEWTON 21 14 21 19 / 30 60 70 80 ELDORADO 23 16 23 18 / 40 60 70 80 WINFIELD-KWLD 25 18 25 19 / 40 60 70 80 RUSSELL 15 10 14 10 / 20 60 70 80 GREAT BEND 15 11 16 13 / 20 60 70 80 SALINA 17 14 16 15 / 20 60 70 80 MCPHERSON 19 13 18 16 / 20 60 70 80 COFFEYVILLE 32 23 26 23 / 80 60 70 80 CHANUTE 29 21 25 21 / 70 60 70 80 IOLA 28 20 25 21 / 70 60 70 80 PARSONS-KPPF 30 22 26 22 / 80 60 70 80 && .ICT WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ053- 069>072-093>096-098>100. WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY AFTERNOON FOR KSZ032-033-047>053-067>072-082-083-091>096-098>100. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ051- 052-067-068-082-083-091-092. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 948 PM EST FRI JAN 12 2007 .UPDATE... VERY INTERESTING WEATHER ACROSS THE CENTRAL CONUS TODAY AND TONIGHT...WITH COLD FRONT SLICING ACROSS THE HEARTLAND OF THE COUNTRY FROM NEAR DETROIT TO INDY TO DALLAS PRODUCING A MONSTER ICE STORM...FOR US HERE IN CENTRAL KENTUCKY AND SOUTH CENTRAL INDIANA WE WILL JUST SEE LIQUID PRECIP FOR THE NEXT FEW DAYS. TEMPERATURES ARE HOLDING NEARLY STEADY IN THE MID 50S ACROSS MUCH OF THE AREA WITH THE SOUTHERLY FLOW AND THE ATMOSPHERE HAS MOISTEN SUBSTANTIALLY IN THE LAST 24 HOURS AS DEWPOINT DEPRESSIONS ARE SHRINKING TO LESS THAN 3 TO 5 DEGREES ACROSS THE REGION WITH THE BLUEGRASS REGION LAGGING SOME HERE WITH DEWPOINTS STILL TRYING TO TOP 50. SHORT RANGE MODELS SUCH AS THE 00Z RUC AND THE 00Z NAM ARE KEEPING THE MAJORITY OF THE STEADY AND HEAVIER PRECIP ACROSS MO/IL/IN WITH THE EDGE NEAR OUR SOUTHERN INDIANA COUNTIES. SOME LIGHT PRECIP WILL STILL BE POSSIBLE ACROSS THE REST OF THE FORECAST AREA BUT WILL BE MORE SCATTERED IN NATURE. HAVE LOWERED POPS ACROSS THE ENTIRE SOUTHEASTERN HALF OF THE AREA INTO THE 50 TO 60 RANGE AS THE BEST MID LEVEL FORCING...SEEN IN THE 700 OMEGAS...REMAINS WELL TO THE NORTH THROUGHOUT THE REST OF THE OVERNIGHT STARTING TO SAG SOUTH ALONG WITH THE FRONTAL BOUNDARY AS WE APPROACH 12Z SATURDAY. THE CURRENT 00Z NAM HAS INITIALIZED WELL PICKING UP ON THE DEVELOPING PRECIP NEAR THE MS RVR AROUND THE AR/MS BORDER AND SHOW IT MOVING ALONG THE MS RVR AND THEN TURNING MORE TOWARDS THE REGION AS THE COLD FRONT APPROACHES THE FORECAST AREA FROM THE NORTHWEST. MODERATE OR HEAVY RAINFALL LOOKS TO BE UNLIKELY BEFORE THE DAYBREAK HOURS ACROSS THE FORECAST AREA...THOUGH THE POSSIBILITY FOR SUCH IS STILL VERY HIGH ON SATURDAY...AND ON INTO MONDAY SO THE FLOOD WATCH WILL CONTINUE ACROSS THE REGION. SCHOTT && .PREV DISCUSSION... /ISSUED 300 PM EDT FRI JAN 12 2007/ SHORT TERM (TONIGHT AND SAT)... THE FLOOD WATCH KICKS IN TONIGHT ACRS OUR ENTIRE FA...HOWEVER SIGNIFICANT RAINS SHUD BE CONFINED TO OUR NRN FA TNGT (SRN INDIANA)...WITH LIGHTER AMOUNTS ACRS CENTRAL KY. HEAVIER RAINS WILL DEVELOP IN CENTRAL KY SAT. EVOVING TROF/UPR LO...EXTENDING FROM MONTANA INTO SRN CA...PROGRESSES VERY SLOWLY EWD THRU THE PERIOD WITH AXIS PROGGED FROM WYOMING TO THE CA/AZ BORDER BY 00Z SUN...RESULTING IN BROAD MOIST SW FLO CONTINUING ACRS THE LOWER OH VLY. CDFNT...WHICH PASSED STL AT 18Z...WILL MAKE STEADY SLOW PROGRESS SEWD TIL SAT MRNG...REACHING NEAR A LINE FROM SOUTH OF PAH TO LOUISVILLE AND NEWD NEAR THE OH RIVER TO CVG. WAVY FRONT THEN BECOMES QUASISTATIONARY SAT...LIKELY STALLING ACRS CENTRAL KY. THIS IS BASICALLY A GFS FCST WITH ENSEMBLE MEMBERS/NCEP IN SUPPORT. AT THE PRESENT...LO LVLS ARE STILL SATURATING AND RAINS HAVE BEEN LIGHT. THE MOIST COLUMN WILL CONTINUE TO DEEPEN TNGT AND SAT WITH FORCING/LIFT ALONG THE FRONT BECOMING THE FOCUS FOR HEAVIEST RAINS TNGT ACRS SCNTRL INDIANA AS THE FRONT MOVES THRU THAT PART OF OUR FORECAST AREA...WITH MODEL QPF SPITTING OUT ONE HALF TO ONE INCH AMOUNTS. LO LVL SWLY FLO WILL BE PERSISTENT ALONG THE FRONT...SUPPORTING THE POTENTIAL FOR TRAINING ALONG THE BOUNDARY. HEAVIER RAINS WILL SHIFT SWD WITH THE FRONT SAT INTO CENTRAL KY...AGAIN WITH RAINFALL AMOUNTS EXPECTED FROM ONE HALF TO ONE INCH. STREAM LEVELS WILL BEGIN TO CLIMB OVER SCNTRL INDIANA LATE TNGT INTO SAT. DITTO FOR CENTRAL KY STREAMS SAT. THE PRIMARY FLOOD/FLASH FLOOD THREAT WILL BEGIN SAT NIGHT WITH AN INCREASING THREAT SUN INTO SUN NIGHT. STILL EXPECTING WIDESPREAD 2-4 INCH 72 HR TOTALS WITH LOCALLY HEAVIER AMOUNTS EXCEEDING 5 INCHES AS STATED IN OUR FLOOD WATCH AND HAZARDOUS WEATHER OUTLOOK...MOST OF THE RAINFALL AFTER SAT. GREATER DETAIL FOLLOWS BELOW... KIRKPATRICK LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)... ..EXCESSIVE RAINFALL TO IMPACT THE REGION SATURDAY NIGHT THROUGH MONDAY MORNING... SATURDAY NIGHT THROUGH MONDAY NIGHT... LATEST SUITE OF SHORT-MEDIUM RANGE MODEL DATA CONTINUES TO SUPPORT ONGOING FCST FOR EXCESSIVE RAINS. FROM A SYNOPTIC STANDPOINT...THE FORECAST SETUP IS A CLASSIC TEXTBOOK EXCESSIVE RAIN/FLOOD EVENT THAT OCCURS IN THE OHIO VALLEY. COMBINATION OF QUASI-STATIONARY FRONTAL BOUNDARY...ABUNDANT MOISTURE AND SEVERAL VORTICITY MAXIMUMA WILL BRING PERIODS OF RAINS TO THE REGION. THE MORNING WRF AND GFS RUNS CONTINUE TO SHOW AXIS OF HEAVIEST PRECIPITATION GENERALLY TRANSLATING SOUTH INTO KENTUCKY LATE SATURDAY NIGHT AND SUNDAY. BY SUNDAY...BOTH MODELS SHOW DECENT SFC WAVE RIDING NE ALONG THE FRONT THAT WILL SIMPLY ADD MORE FUEL TO THE FIRE FOR THE RAINS. AS THIS WAVE MOVES NORTHEAST...BRUNT OF PRECIPITATION ACCUMULATION WILL OCCUR DURING THIS TIME PERIOD. WHILE OVERALL INSTABILITY IS LACKING...STRONG FORCING FROM SFC CONVERGENCE ALONG FRONT AS WELL AS LARGE SCALE FORCED ASCENT FROM APPROACHING SFC WAVE WILL BRING PERIODS OF HEAVIER/CONVECTIVE RAINS TO THE REGION MAINLY SUNDAY AFTERNOON/EVE. ADDITIONALLY TOTAL-TOTALS ARE FORECAST TO RISE INTO THE UPPER 40S AND WITH SOME ELEVATED INSTABILITY...HAVE OPTED TO KEEP SCT THUNDER IN THE FCST...BUT OVERALL SEVERE THREAT LOOKS MORE MINIMAL AT THIS TIME. AS FOR RAINFALL AMOUNTS...TOTAL PRECIPITATION ACCUMULATIONS OF 2 TO 4 INCHES STILL LOOK GOOD FOR THIS FORECAST PERIOD. SOME LOCALLY HIGHER AMOUNTS ARE POSSIBLE ESPECIALLY IF A THUNDERSTORM DEVELOPS. THEREFORE THE FLOOD WATCH WILL CONTINUE. GIVEN HIGH CONFIDENCE OF RAINFALL...HAVE INCREASED POPS TO 100 PERCENT FOR SATURDAY NIGHT THROUGH EARLY MONDAY MORNING. TEMPERATURES WILL CONTINUE TO BE CHALLENGING ON SUNDAY AS FRONTAL BOUNDARY WILL BE BISECTING THE REGION. THE WRF AND GFS FRONTAL SOLUTIONS ARE IN BETTER AGREEMENT...THOUGH THE WRF IS SLIGHTLY FARTHER SOUTH THAN THE GFS. THIS IS MOST LIKELY DUE TO IT BEING ABLE TO HANDLE THE ARCTIC AIRMASS TO OUR NORTH SOMEWHAT BETTER THAN THE GFS. IN A NUTSHELL...A GRADIENT OF TEMPERATURES ARE LIKELY WITH HIGHS RANGING IN THE MID TO UPPER 40S ACROSS SOUTHERN INDIANA TO THE MID AND UPPER 50S ACROSS SOUTHERN KY. AS SFC WAVE LIFTS NORTHEAST OF THE AREA LATE SUNDAY NIGHT AND EARLY MONDAY...PRECIPITATION WILL GRADUALLY DIMINISH IN INTENSITY. MODIFIED POLAR AIRMASS WILL THEN BUILD INTO THE REGION AS PRECIPITATION EXITS. THEREFORE...THE IDEA OF RAIN SHOWERS CHANGING TO SNOW SHOWERS ON MONDAY STILL LOOKS GOOD AT THIS POINT. AT THIS TIME...A CHANGE OVER IN OUR NORTHWEST MONDAY MORNING LOOKS REASONABLE. A CHANGEOVER IN THE LOUISVILLE AREA WOULD COMMENCE IN THE AFTERNOON AND IN OUR EAST...IT WOULD BE LATER IN THE EVENING. HIGHS FOR MONDAY WILL LIKELY BE IN THE MORNING WITH READINGS FALLING THROUGHOUT THE DAY. GENERALLY WILL TREND TEMPS CLOSE TO THE RAW 2M GFS OUTPUT. TUESDAY THROUGH FRIDAY... NOT MUCH CHANGE IN THE FORECAST THROUGH THIS TIME PERIOD. WITH FRONT CONTINUING TO OUR SOUTH AND HIGH PRESSURE BUILDING IN FROM THE UPPER PLAINS...NORTHERLY WINDS WILL GET THE LAKE-EFFECT SNOW MACHINE GOING TO OUR NORTH. DOWN THIS FAR SOUTH...FEEL THAT SCT FLURRIES WILL BE POSSIBLE DURING THE DAY ON TUESDAY AND WILL LEAVE AS SUCH. BETTER CHC FOR SNOW SHOWERS WOULD EXIST OVER FAR EAST KY IN THE FAVORED UPSLOPE REGIONS. DRY FORECAST IS ANTICIPATED FOR WEDNESDAY THROUGH FRIDAY AS HIGH PRESSURE CONTINUES TO BUILD OVER THE REGION. TEMPERATURES AT THE BEGINNING OF THIS PD WILL BE WELL BELOW NORMAL WITH HIGHS IN THE UPPER 20S TO LOWER 30S AND OVERNIGHT LOWS IN THE UPPER TEENS. SOME MODERATION IN THE TEMPERATURES WILL OCCUR BY THURSDAY AND FRIDAY WITH TEMPERATURES WARMING SLIGHTLY INTO THE MID AND UPPER 30S. GENERALLY STUCK CLOSE TO THE HPC GUIDANCE THROUGH THIS PERIOD. -MJ .LMK WATCHES/WARNINGS/ADVISORIES... KY...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR KYZ023>043-045>049- 053>057-061>067-070>078-081-082. IN...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR INZ076>079-083-084- 089>092. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1035 AM EST FRI JAN 12 2007 .UPDATE...RUC AND LAPS ANALYSIS SHOW THAT THE SFC TROUGH/COLD FRONT IS PRETTY MUCH THROUGH THE MOST OF N LOWER. THE NW FLOW IN E UPPER AND SFC TEMPERATURES FALLING INTO THE UPPER 20S ALONG LAKE SUPERIOR SHORELINE AT WHITEFISH POINT AND GRAND MARAIS SHOWING THAT THE COLD AIR IS BEGINNING TO OOZE INTO THE REGION. MID 30S IS THE RULE OVER MOST N LOWER WITH THE TEMPERATURES EXPECTED TO FALL DURING THE AFTERNOON. WINDS ARE BEGINNING TO SHIFT NORTH IN NW LOWER WITH RAWS SITE BEAR(SLEEPING BEAR DUNES NEAR EMPIRE) AND GRAND TRAVERSE LIGHT SHOWING NORTH WINDS AND MOST OF THE ASOS/AWOS SITES SHOWING NW WINDS. INTERIOR SITES AND NE LOWER SITES ARE EITHER CALM OR WINDS LIGHT SW. HIGHS HAVE BEEN REACHED OR WILL BE REACHED SOON, SO THE MAIN CONCERNS WILL BE THE HOURLY TEMPERATURES FALLING DURING THE DAY AND THE CHANCE FOR SNOW AS THE COLDER 850 AIR, AND SPECIFICALLY THE -10C LINE, ADVANCING INTO THE E UPPER AND N LOWER FOR THE AFTERNOON. AS OF 15Z RUC40 ANALYSIS/1HR FORECAST -10C WAS THROUGH MOST OF WHITEFISH BAY TO CURTIS LINE AND ADVANCING STEADILY. 12Z NAM IS MUCH SLOWER WITH THE -10C AIR AROUND MONTREAL RIVER, ONTARIO TO GRAND MARAIS, MI LINE. WITH KERY ALREADY SHOWING SNOW/FLURRIES WOULD THINK THAT THE 14Z RUC40 IS CLOSER TO REALITY. SO THINK THAT THE CURRENT FORECAST TRANSITIONS OF SNOW/DRIZZLE ARE CURRENTLY GOOD, BUT SFC TEMPERATURES NEED TO BE ADJUSTED SLIGHTLY. ZONES OUT SHORTLY. LUTZ && .PREV DISCUSSION...ISSUED 400 AM EST FRI JAN 12 2007 COLD FRONT EARLY THIS MORNING EXTENDED FROM NEAR THE SAULT...SW ACROSS LAKE MI AND SE WI...TO MISSOURI. RADAR AND SURFACE OBS SUPPORT DRIZZLE AND PATCHY LIGHT RAIN ACROSS FORECAST AREA. AS EXPECTED...FREEZING PRECIP HAS HELD OFF THUS FAR AS SURFACE TEMPS HAVE HELD ABOVE FREEZING IN ADVANCE OF FRONT. FRONT IS FORECAST TO DROP SE ACROSS THE REGION TODAY...REACHING SE LOWER MI BY LATE THIS AFTERNOON. AS COLDER AIR FILTERS SEWD BEHIND FRONT...FORECAST CONCERNS WILL INCLUDE PRECIP TYPE/COVERAGE THROUGH TONIGHT. TODAY AND TONIGHT...IR/WV LOOP SHOWS LITTLE IN THE WAY OF DEEP/LAYERED MOISTURE UPSTREAM...SUGGESTING THAT ANY PRECIP THAT FALLS TODAY WILL REMAIN ON THE LIGHT SIDE. THIS IS CONSISTENT WITH NAM/GFS MODEL SOUNDINGS...WITH SHALLOW MOISTURE GENERALLY CONFINED TO TEMPS OF -8C AND WARMER. CAA PATTERN WILL SUPPORT PROGRESSIVELY COOLER AIR FROM NW TO SE DURING THE DAY. AS A RESULT...EXPECT DRIZZLE OR PATCHY VERY LIGHT RAIN ACROSS NRN LOWER...WITH SOME PATCHY LIGHT MIXED PRECIP IN ERN UPPER EARLY. ANTICIPATE A GRADUAL TRANSITION TO SPOTTY LIGHT SNOW SHOWERS DURING THE AFTERNOON. HOWEVER...WILL RETAIN SOME PATCHY DRIZZLE THROUGH THE AFTERNOON IN SE AREAS...WHERE COOLER AIR ARRIVES LAST. COOLER AIR CONTINUES TO OVERSPREAD REGION TONIGHT...WITH 850 MB TEMPS FALLING TO AROUND -12C. N/NW WINDS WILL SUPPORT SOME LAKE EFFECT SNOW IN NW LOWER AND E UPPER THIS EVENING. HOWEVER...WITH SURFACE RIDGE DROPPING S THROUGH LAKE SUPERIOR...ANTI-CYCLONIC FLOW...INVERSION HEIGHTS NEAR 3 KFT...AND 850-700 MB RH HOVERING AROUND 60%...DON/T EXPECT MUCH ACCUMULATION. SATURDAY...COLD FRONT WILL DROP TO VICINITY OF OHIO RIVER AND STALL. LIGHT NORTHERLY FLOW ACROSS NRN MICHIGAN COUPLED WITH 850 MB TEMPS OF -12 TO -14C WILL SUPPORT MORNING FLURRIES EARLY NEAR LAKES MICHIGAN...HURON...AND SUPERIOR. HOWEVER...WITH SURFACE RIDGE DROPPING INTO NRN LOWER BY AFTERNOON...EXPECT FLURRIES TO END WITH PARTLY TO MOSTLY CLOUDY SKIES FOR THE AFTERNOON. SUNDAY...STALLED FRONT WILL REMAIN WELL S OF REGION...AS WAVES OF ENERGY PUSH ENEWD ALONG FRONT SPREADING SOME MOISTURE INTO CENTRAL AND SRN LOWER MI. MEANWHILE...A SURFACE TROUGH WILL DROP THROUGH THE NRN LAKES AND PROVIDE A REINFORCING SHOT OF COLDER AIR. UPSHOT... EXPECT MOSTLY CLOUDY SKIES WITH PATCHY LIGHT SNOW OR SNOW SHOWERS AND LITTLE IF ANY ACCUMULATION. SMITH SUNDAY NIGHT THROUGH TUESDAY...MOST POTENTIAL FOR SIGNIFICANT SNOWFALL OVER THE NEXT 7 DAYS FROM SUNDAY NIGHT THROUGH MONDAY. AT THIS TIME...NOT INCLINED TO MAKE ANY CHANGES TO THE ONGOING FORECAST. MODELS HAVE ACTUALLY BEEN DIVERGING THE PAST FEW RUNS...SO CANNOT PIN DOWN A MORE DEFINITIVE STORM TRACK AS OF THIS TIME. AS MENTIONED IN PREVIOUS DISCUSSIONS... THE TRACK OF A DEVELOPING STORM SYSTEM WILL PLAY A BIG ROLE AS TO HOW MUCH SNOW NORTHERN MICHIGAN SEES EARLY NEXT WEEK. THE 00Z GFS CONTINUES TO TREND FURTHER SOUTH WITH THE STORM TRACK...TAKING THE SYSTEM FROM CENTRAL KENTUCKY... THROUGH MARYLAND...THEN OFF INTO THE NORTHERN ATLANTIC. MEANWHILE...THE MORE CONSISTENT ECMWF KEEPS A NORTHERLY TRACK FROM SOUTHERN MISSOURI...THROUGH NORTHERN OHIO...AND INTO NORTHERN NEW ENGLAND. THE GFS SOLUTION WOULD YIELD LESS WIDESPREAD SNOWFALL... WITH MORE EMPHASIS ON LAKE EFFECT...WHILE THE ECMWF WOULD PROVIDE MORE OF A SUBSTANTIAL SNOWFALL TO THE AREA...ESPECIALLY NORTHEAST LOWER MICHIGAN...WHERE SNOWFALL WOULD BE ENHANCED WITH 850MB TEMPS STARTING OFF AROUND -8C...THEN FALLING RAPIDLY. MODELS SEEM TO AGREE ON KEEPING A LAKE INDUCED TROUGH OVER THE GREAT LAKES INTO TUESDAY. NORTH TO NORTHWEST FLOW WILL PROVIDE LAKE EFFECT SNOW SHOWERS TO LOCATIONS ALONG THE LAKE MICHIGAN AND LAKE HURON COASTLINES. OTHERWISE...THE TREND IN OVERALL SNOWFALL WILL BE ON THE DECLINE...ESPECIALLY ACROSS INTERIOR LOCATIONS OF NORTHERN MICHIGAN. KAS && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 412 PM EST THU JAN 11 2007 .SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING EXTENDING FROM HUDSON BAY TO NORTHERN CALIFORNIA AND RIDGING OVER THE SOUTHEAST U.S.. THERE ARE A FEW WEAK SHRTWVS MOVING THROUGH THE SW FLOW BETWEEN THE TROUGH AND RIDGE...BUT DUE TO THE PRESENCE OF DRY AIR IN THE MID-LEVELS AS SEEN ON 12Z SOUNDING...NOT MUCH IS OCCURRING WITH THEM. ONE OF THE SHRTWVS IS MOVING THROUGH EASTERN NEBRASKA...AND WHEN COMBINED WITH SOME UPPER DIVERGENCE IN THE RIGHT REAR QUADRANT OF A 130KT JET MAX MOVING THROUGH NORTHERN ONTARIO AND 800-600MB FRONTOGENESIS...HAS HELPED TO PRODUCE BANDS OF LIGHT TO MODERATE REFLECTIVITIES IN MINNESOTA. HOWEVER...AGAIN WITH THE PRESENCE OF DRY AIR...VERY FEW LOCATIONS ARE REPORTING SNOWFALL. CLOSER TO HOME...TEMPERATURES ARE AGAIN ABOVE NORMAL AHEAD OF A COLD FRONT. THIS COLD FRONT EXTENDS FROM A 1009 MB LOW IN NORTHERN LAKE SUPERIOR...ACROSS THE WESTERN U.P. AND INTO THE TEXAS PANHANDLE. BEHIND THE COLD FRONT...NORTHWEST WINDS CONTINUE TO ADVECT IN COLD AIR FROM THE PLAINS. RIGHT NOW READINGS ARE IN THE SINGLE DIGITS BELOW ZERO F OVER NORTH DAKOTA AND EVEN NEAR 20 BELOW F OVER CENTRAL MANITOBA. THE ACTUAL SURFACE HIGH ASSOCIATED WITH THE COLD READINGS IS LOCATED IN CENTRAL SASKATCHEWAN (PRESSURE NEAR 1040MB). && .DISCUSSION... SHRTWV OVER EASTERN NEBRASKA IS PROGGED TO MOVE ACROSS THE CWA LATER TONIGHT...ALLOWING THE COLD FRONT TO BEGIN MAKING MORE OF A PUSH EASTWARD. THIS SHRTWV...COMBINED WITH THE UPPER DIVERGENCE AND FRONTOGENESIS MENTIONED EARLIER...MAY SUPPORT SOME LIGHT SNOW OVER THE CWA TONIGHT. HOWEVER...WITH THE DRY AIR IN THE MID LEVELS... ACTUAL PCPN AMOUNTS SHOULD REMAIN SMALL. WAS NEARLY TEMPTED TO MENTION SOME FREEZING DRIZZLE DUE TO THE LOW LEVELS MOISTENING UP BEHIND THE COLD FRONT...BUT THE SEEDER-FEEDER PROCESS LOOKS TO OCCUR AT THE TIME THE LOW LEVELS MOISTEN...SO KEPT THE FREEZING DRIZZLE MENTION OUT. ALSO...AS THE COLD FRONT PASSES...THE COLDER AIR SEEN OVER NORTHERN MINNESOTA AND THE PLAINS WILL ADVECT INTO THE CWA...ALLOWING FOR SOME LES TO START UP. LOW INVERSION HEIGHTS AND LACK OF CONVERGENCE WILL KEEP THE SNOW LIGHT. THEREFORE SNOW ACCUMULATION AMOUNTS FOR ALL OF TONIGHT SHOULD ONLY BE AN INCH OR LESS. HAVE RAISED TEMPERATURES IN THE EASTERN CWA AS IT LOOKS LIKE THE COLD AIR WILL TAKE THE LONGEST TO GET THERE...AND ALSO MATCHES BETTER WITH MAV/MET GUIDANCE. COLDEST TEMPERATURES EXPECTED OUT WEST WHERE COLDER AIR MAKES IT IN FIRST. ON FRI...THE UPPER TROUGH IS PROGGED TO SPLIT IN TWO AS A RESULT OF A POLAR LOW DROPPING S THROUGH THE NUNAVUT REGION WHICH INDUCES RIDGING OVER SOUTH CENTRAL CANADA. THIS MOTION ALLOWS FOR THE HIGH PRESSURE AREA OVER SASKATCHEWAN TO DROP DOWN INTO THE DAKOTAS. NORTHERLY FLOW ON THE EAST SIDE OF THE HIGH WILL CONTINUE TO DRAG COLDER AIR INTO UPPER MICHIGAN...AS NOTED TOO BY 850MB TEMPS ON THE GFS/NAM FALLING TO -16 TO -20C BY 00Z SAT. THEREFORE MOST IF NOT ALL LOCATIONS SHOULD SEE THEIR HIGHS IN THE MORNING...WITH READINGS FALLING THROUGH THE DAY. THIS COLD ADVECTION IS ALSO ASSOCIATED WITH DRY AIR...ESPECIALLY GIVEN THAT RIGHT NOW PICKLE LAKE ONTARIOS DEWPOINT IS -17F. SO ALTHOUGH LAKE EFFECT SNOW SHOWERS ARE EXPECTED DUE TO THE COLD AIR...THAT DRY AIR AND CONTINUED LOW INVERSION HEIGHTS SHOULD KEEP SNOWFALL AMOUNTS AT AN INCH OR LESS...ESPECIALLY WITH NO CONVERGENCE AREAS ANTICIPATED. FOR FRI NIGHT INTO SAT...GFS/UKMET/ECMWF ALL SHOW THE UPPER LOW OVER THE NUNAVUT AREA DROPPING INTO HUDSON BAY...MAINTAINING A WESTERLY FLOW ALOFT AT 500MB OVER UPPER MICHIGAN. THE RESULT OF THE LOW DROPPING SOUTHWARD IS TO CAUSE THE HIGH PRESSURE AREA OVER THE DAKOTAS TO EXPAND EASTWARD. IN FACT...BY 18Z SAT...THE MODELS SUGGEST THAT THE AREA WILL DROP S OF THE AREA. THEREFORE...LIGHT LAKE EFFECT SNOW SHOWERS THAT ARE OCCURRING OVER THE NORTHERN U.P. WILL CONTINUE INTO SAT MORNING...BEFORE THE WINDS TURN WSW AND PUSH MUCH OF THE LAKE EFFECT OFFSHORE. IT APPEARS THAT WITH THE WINDS LIGHTENING DUE TO THE HIGH PRESSURE RIDGE BUILDING IN FRI NIGHT... LAND BREEZES ARE EXPECTED TO BECOME MORE OF AN INFLUENCE... ALLOWING FOR SOME AREAS OF CONVERGENCE TO DEVELOP. HOWEVER... SOUNDINGS CONTINUE TO SHOW LOW INVERSION HEIGHTS (UNDER 5000FT) AND PLENTY OF DRY AIR...SO EVEN CONVERGENT BANDS SHOULD NOT PRODUCE MUCH SNOW. TEMPERATURES WILL BE RELATIVELY COOL FRI NIGHT... ESPECIALLY GIVEN THE COLD AIR THAT ENTERED THE CWA ON FRI. HOWEVER...THESE READINGS ARE AROUND NORMAL. IF MORE CLEARING OCCURS...ESPECIALLY IN THE INTERIOR...SOME BELOW ZERO READINGS ARE LIKELY. RETURN FLOW SETTING UP ON SAT SHOULD ALLOW TEMPERATURES TO REBOUND A BIT...BACK UP INTO THE UPPER TEENS/LOW 20S. IN FACT...THE GFS SHOWS 850MB TEMPS WARMING TO AROUND -12C BY 00Z SUN. SAT NIGHT INTO SUN...UPPER LOW OVER HUDSON BAY IS PROGGED TO MOVE INTO NW QUEBEC SUN MORNING AND THEN INTO NEWFOUNDLAND BY 00Z MON. A COLD FRONT ASSOCIATED WITH THIS UPPER LOW IS EXPECTED TO MOVE INTO THE CWA SUN MORNING...FOLLOWED BY ANOTHER CANADIAN HIGH PRESSURE AREA WHICH BUILDS INTO THE DAKOTAS LATE SUN. DRY AIR AHEAD OF THE FRONT SHOULD KEEP IT PRECIPITATION FREE. HOWEVER...ANOTHER SURGE OF COLD AIR BEHIND THE FRONT WILL RESULT IN MORE LAKE EFFECT SNOW. AGAIN...THE AIR SINCE IT IS OF ARCTIC ORIGIN WILL NOT HAVE MUCH MOISTURE WITH IT...KEEPING THE LAKE EFFECT LIGHT. ALTHOUGH COOLER AIR IS HEADING INTO THE CWA...850MB TEMPS FALLING TO NEAR -19C BY 00Z MON PER THE GFS...SURFACE TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL DUE TO NORTHERLY FLOW BRINGING LAKE SUPERIOR MODIFIED AIR INTO THE CWA. EXTENDED (MON THROUGH THU)...OPERATIONAL MODELS ARE IN OVERALL GOOD AGREEMENT DURING THIS TIME PERIOD...SUGGESTING IN THE MEAN TROUGHING TO REMAIN OVER THE GREAT LAKES AND RIDGING IN WESTERN NORTH AMERICA...A TYPICAL WINTER TIME PATTERN. AS THE SYSTEM IN THE OHIO VALLEY MOVES OFF TO THE NE SUN NIGHT...NORTHERLY FLOW BEHIND IT WILL CONTINUE TO DRAG COLDER BUT DRY AIR SOUTHWARD ACROSS LAKE SUPERIOR. BY 00Z TUE...THE ECMWF SHOWS 850MB TEMPS FALLING ABOUT 6C FROM 00Z MON TO -19C. THEREFORE EXPECT SOME LAKE EFFECT SNOW TO OCCUR...BUT NOTHING TOO HEAVY DUE TO THE DRY AIR AND LOW INVERSION HEIGHTS AS SEEN ON GFS SOUNDINGS. THIS POOL OF COLD AIR WILL BEGIN TO HEAD OFF TO THE E ON TUE AS A PORTION OF THE WESTERN NORTH AMERICA RIDGE IS PUSHED INTO CENTRAL CANADA. LAKE EFFECT WILL PROBABLY PERSIST INTO TUE...BUT WITH A SURFACE RIDGE MOVING IN RESULTING IN EVEN DRIER AIR AND LOWER INVERSIONS... NOT EXPECTING A LOT OF SNOWFALL. ON WED...THE RIDGE AXIS OVER CENTRAL CANADA WILL MOVE SE OVER UPPER MICHIGAN AS A RESULT OF A CLIPPER SYSTEM MOVING DOWN FROM THE NORTHWEST TERRITORIES. THE 06Z GFS/00Z ECMWF BOTH DEPICT THIS CLIPPER TO BE LOCATED OVER NW ONTARIO. BOTH MODELS DEPICT THE BETTER LIFT STAYING NORTH OF LAKE SUPERIOR...AND WITH A DRY AIRMASS ALREADY IN PLACE FROM TUE...PREFER NOT TO INSERT ANY POPS FOR THE CLIPPER. HOWEVER...WSW WARM AIR ADVECTION AHEAD OF THE CLIPPER WILL RESULT IN A BREEZY DAY. BY 00Z THU...THE ECMWF SHOWS 850MB TEMPS CLIMBING UP TO 10C...SO LAKE EFFECT WILL LIKELY NOT SHUT OFF BUT JUST RE-ALIGN TO THE WIND DIRECTION. FOR WED NIGHT INTO THU...A TROUGH ASSOCIATED WITH THE CLIPPER ALONG WITH AN UPPER LEVEL SHRTWV ARE PROGGED TO MOVE ACROSS THE CWA...SO KEPT SOME LOW CHANCE POPS IN FOR THOSE. OVERALL THOUGH...THROUGHOUT THE EXTENDED...IT DOES NOT APPEAR THAT MUCH PRECIPITATION IS GOING TO OCCUR. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1125 AM EST THU JAN 11 2007 .UPDATE... WATER VAPOR IMAGERY SHOWS A SHORTWAVE TRACKING THRU ONTARIO. AT THE SFC...ASSOCIATED BROAD SFC LOW APPEARS TO BE CENTERED OVER FAR NRN LAKE SUPERIOR. TROFFINESS HANGS BACK ACROSS NRN MN WITH ARCTIC AIR JUST TO THE N IN ONTARIO AND MANITOBA. FARTHER W...ARCTIC AIR IS SURGING S ACROSS THE DAKOTAS. UPPER DIVERGENCE IN RIGHT ENTRANCE OF JET ASSOCIATED WITH ONTARIO SHORTWAVE IS LEADING TO RADAR RETURNS IN NE MN...BUT HAVE NOT SEEN ANY SFC OBS INDICATING PCPN. LOW-LEVEL JET HAS SHIFTED E OF FCST AREA...AND WITH BAGGY PRES GRADIENT DEVELOPING...WINDS ARE DIMINISHING FROM W TO E THIS MORNING. GOING FCST IS IN GOOD SHAPE FOR THE AFTN AND REQUIRES LITTLE IF ANY CHANGE. AS UPPER JET TRANSLATES E THIS AFTN...UPPER DIVERGENCE WILL ALSO SHIFT E. GIVEN THE RADAR RETURNS IN NE MN...IT IS NOT OUT OF THE QUESTION THAT A FEW -SHSN MAY DEVELOP OVER THE FAR W TOWARD EVENING. OTHERWISE...EXPECT A DRY AFTN. CLOUDS SHOULD GENERALLY HOLD TOUGH THRU THE AFTN...BUT VIS SATELLITE IMAGERY INDICATES CLOUDS ARE FAIRLY THIN ACROSS NRN WI INTO SRN UPPER MI. THIS MAY ALLOW TEMPS TO GET A COUPLE OF DEGREES HIGHER THAN 36-38F IN THE GOING FCST. && .PREV DISCUSSION... ISSUED AT 330 AM EST 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WSW FLOW ALF BTWN DEEPENING TROF OVER THE PAC NW (12Z-24Z H3 HGT FALLS UP TO 200M THERE WITH SHRTWV DIGGING ALG THE PAC NW COAST) AND UPR RDG AXIS MOVING INTO SE ONTARIO. STRONG SHRTWV EMBEDDED WITHIN THIS FLOW IS MOVING INTO SRN MANITOBA...WITH ONLY WEAK SFC LO OVER ERN ND JUST NW OF FAR. STRONG ISENTROPIC ASCENT NOTED IN ADVANCE OF THIS SHRTWV... AND MQT VWP SHOWS S WINDS UP TO 55KT AT 3K FT MSL. GALE FORCE WINDS OBSVD OVER LK SUP FM ISLE ROYALE TO STANNARD ROCK. STRONG WAD HAS CONTRIBUTED TO EXTENSIVE MID CLD DECK OVER THE UPR GRT LKS...BUT DRY AIR SHOWN ON THE 00Z GRB RAOBS/ TAMDAR SDNG FM SAW BTWN H9-775 OR SO HAS RESTRICTED SN FOR THE MOST PART TO THE COLD SIDE OF H85 WARM FNT...LOCATED AT 00Z FM CKC-CMX-ERY...WHERE 0Z GFS F6 ALSO SHOWS SOME UPR DVGC. LTL IF ANY PCPN NOTED CLOSER TO THE SFC LO AND ALG ATTENDANT LO PRES TROF STRETCHING TO THE SW AS 00Z BIS/ABR/MPX SDNGS EXCESSIVELY DRY. MUCH COLDER AIR OBSVD OVER MT/ADJOINING AREAS IN SRN CAN. MAIN FCST CONCERNS THIS PACKAGE ARE PCPN CHCS ASSOCIATED WITH SHRTWV/SFC LO TO THE WNW TDAY AND THEN DISTURBANCES IN WSW FLOW ALF IN THE WAKE OF THIS SHRTWV LATER AS VERY COLD AIR TO THE NW POISED TO MOVE INTO THE UPR GRT LKS. FOR TDAY...NAM/GFS/UKMET SHOW SFC LO OVER NE MN THIS MRNG MOVING ACRS NRN LK SUP INTO SE ONTARIO BY 00Z AS SHRTV NR LK WINNIPEG SHEARS ENE ACRS ONTARIO...WITH ATTENDANT LO PRES TROF DRIFTING INTO THE CNTRL ZNS BY 00Z FRI. GIVEN EXCESSIVELY DRY AIRMASS UPSTREAM AT BIS/MPX/ ABR...PREFER THE DRIER NAM FCST (ZERO QPF) AS SHARPER ISENTROPIC LIFT/H85-5 QVECTOR CNVGC/LINGERING UPR DVGC/DEEPER MSTR EXIT EARLY THIS MRNG AND GIVE WAY TO DRYING ALF/H85-5 QVECTOR DVGC BY 18Z. IN FACT...GFS FCST SDNGS DEPICT THIS MID LVL DRYING QUITE WELL ABV INCREASINGLY SHALLOW MOIST LYR. TDAY WL BE WARMEST DAY OF NEXT WEEK AT LEAST AS SW FLOW IN ADVANCE OF APRCHG LO PRES TROF ADVECTS WARMER AIR FM THE SW...WHERE HI TEMPS REACHED NR 40 OR SRN MN ON WED...INTO THE FA. GFS/UKMET/NAM SHOW A STRIPE OF HIER MID LVL RH DVLPG OVER THE NRN PLAINS THIS AFTN AND STREAKING ENE INTO THE WRN CWA LATE TDAY/TNGT/ FRI AS WAVES OF UPR DVGC IN RRQ OF H3 JET MAXES/SHRTWVS SHEARING ENEWD THRU WSW FLOW ALF IN CONFLUENCE ZN BTWN NRN/SRN BRANCHES AS WELL AS ACCOMPANYING H8-7 FGEN OVER RELATIVELY SHALLOW COLD AIR TO THE NW OF ARCTIC BNDRY NOW SEPARATING VERY COLD AIR IN MT/SRN CAN FM WARMER AIR STILL IN THE NRN PLAINS/MN THAT IS FCST TO GRDLY OOZE SE ACRS THE UPR LKS. THINK TRYING TO TIME EACH OF THESE WAVES WL BE FRUITLESS ATTM...SO WL CARRY CHC POPS ACRS MOST OF THE AREA THRU FRI TO ACCOUNT FOR THIS FGEN FORCING/POTENTIAL LES AS COLDER AIR GRDLY OVERSPRDS THE FA. IN GENERAL...WL GO WITH HIER CHC POPS TO THE NW EARLY IN THE PD AND GRDLY SHIFT THE HIER POPS TO THE SE AS ARCTIC BNDRY DRIFTS SLOWLY SE WITH TIME. RELATIVELY SHALLOW DEPTH OF COLD AIR AS WELL AS NEUTRAL-ALMOST ACYC LARGER SCALE LLVL FLOW WOULD SUG ANY LES WL BE ON THE LGT SIDE DESPITE ARRIVAL OF MUCH COLDER AIR BLO SHALLOW INVRN (GFS/NAM SHOW INVRN BASE TEMPS APRCHG -20C OVER THE NW BY LATE FRI). WL TEND TOWARD THE LO SIDE OF MOS GUIDANCE GIVEN HI STABILITY/SHALLOW NATURE OF ENCROACHING ARCTIC AIR. ON FRI NGT/SAT...UPR CONFLUENCE ZN PROGGED TO PUSH FAR ENUF S THAT DRY ARCTIC HI PRES CENTER DRIFTS OVER THE FA. WL DIMINISH POPS TO NO HIER THAN 30 NR LK SUP ON LATE FRI NGT/SAT TO REFLECT INCRSGLY HOSTILE CONDITIONS FOR LES. MADE A FEW CHGS TO THE SAT NGT/SUN PD TO REFLECT TREND TOWARD MORE AGGRESSIVE NRN BRANCH THAT WL AT LEAST DELAY THE PROGRESSION OF THE SW UPR TROF TO THE NE. IN GENERAL CUT POPS A BIT DURING THIS TIME WITH GREATER INFLUENCE OF DRIER NRN BRANCH. COORDINATED WITH GRB. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (UPDATE) KC (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 330 AM EST THU JAN 11 2007 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WSW FLOW ALF BTWN DEEPENING TROF OVER THE PAC NW (12Z-24Z H3 HGT FALLS UP TO 200M THERE WITH SHRTWV DIGGING ALG THE PAC NW COAST) AND UPR RDG AXIS MOVING INTO SE ONTARIO. STRONG SHRTWV EMBEDDED WITHIN THIS FLOW IS MOVING INTO SRN MANITOBA...WITH ONLY WEAK SFC LO OVER ERN ND JUST NW OF FAR. STRONG ISENTROPIC ASCENT NOTED IN ADVANCE OF THIS SHRTWV... AND MQT VWP SHOWS S WINDS UP TO 55KT AT 3K FT MSL. GALE FORCE WINDS OBSVD OVER LK SUP FM ISLE ROYALE TO STANNARD ROCK. STRONG WAD HAS CONTRIBUTED TO EXTENSIVE MID CLD DECK OVER THE UPR GRT LKS...BUT DRY AIR SHOWN ON THE 00Z GRB RAOBS/ TAMDAR SDNG FM SAW BTWN H9-775 OR SO HAS RESTRICTED SN FOR THE MOST PART TO THE COLD SIDE OF H85 WARM FNT...LOCATED AT 00Z FM CKC-CMX-ERY...WHERE 0Z GFS F6 ALSO SHOWS SOME UPR DVGC. LTL IF ANY PCPN NOTED CLOSER TO THE SFC LO AND ALG ATTENDANT LO PRES TROF STRETCHING TO THE SW AS 00Z BIS/ABR/MPX SDNGS EXCESSIVELY DRY. MUCH COLDER AIR OBSVD OVER MT/ADJOINING AREAS IN SRN CAN. MAIN FCST CONCERNS THIS PACKAGE ARE PCPN CHCS ASSOCIATED WITH SHRTWV/SFC LO TO THE WNW TDAY AND THEN DISTURBANCES IN WSW FLOW ALF IN THE WAKE OF THIS SHRTWV LATER AS VERY COLD AIR TO THE NW POISED TO MOVE INTO THE UPR GRT LKS. FOR TDAY...NAM/GFS/UKMET SHOW SFC LO OVER NE MN THIS MRNG MOVING ACRS NRN LK SUP INTO SE ONTARIO BY 00Z AS SHRTV NR LK WINNIPEG SHEARS ENE ACRS ONTARIO...WITH ATTENDANT LO PRES TROF DRIFTING INTO THE CNTRL ZNS BY 00Z FRI. GIVEN EXCESSIVELY DRY AIRMASS UPSTREAM AT BIS/MPX/ ABR...PREFER THE DRIER NAM FCST (ZERO QPF) AS SHARPER ISENTROPIC LIFT/H85-5 QVECTOR CNVGC/LINGERING UPR DVGC/DEEPER MSTR EXIT EARLY THIS MRNG AND GIVE WAY TO DRYING ALF/H85-5 QVECTOR DVGC BY 18Z. IN FACT...GFS FCST SDNGS DEPICT THIS MID LVL DRYING QUITE WELL ABV INCREASINGLY SHALLOW MOIST LYR. TDAY WL BE WARMEST DAY OF NEXT WEEK AT LEAST AS SW FLOW IN ADVANCE OF APRCHG LO PRES TROF ADVECTS WARMER AIR FM THE SW...WHERE HI TEMPS REACHED NR 40 OR SRN MN ON WED...INTO THE FA. GFS/UKMET/NAM SHOW A STRIPE OF HIER MID LVL RH DVLPG OVER THE NRN PLAINS THIS AFTN AND STREAKING ENE INTO THE WRN CWA LATE TDAY/TNGT/ FRI AS WAVES OF UPR DVGC IN RRQ OF H3 JET MAXES/SHRTWVS SHEARING ENEWD THRU WSW FLOW ALF IN CONFLUENCE ZN BTWN NRN/SRN BRANCHES AS WELL AS ACCOMPANYING H8-7 FGEN OVER RELATIVELY SHALLOW COLD AIR TO THE NW OF ARCTIC BNDRY NOW SEPARATING VERY COLD AIR IN MT/SRN CAN FM WARMER AIR STILL IN THE NRN PLAINS/MN THAT IS FCST TO GRDLY OOZE SE ACRS THE UPR LKS. THINK TRYING TO TIME EACH OF THESE WAVES WL BE FRUITLESS ATTM...SO WL CARRY CHC POPS ACRS MOST OF THE AREA THRU FRI TO ACCOUNT FOR THIS FGEN FORCING/POTENTIAL LES AS COLDER AIR GRDLY OVERSPRDS THE FA. IN GENERAL...WL GO WITH HIER CHC POPS TO THE NW EARLY IN THE PD AND GRDLY SHIFT THE HIER POPS TO THE SE AS ARCTIC BNDRY DRIFTS SLOWLY SE WITH TIME. RELATIVELY SHALLOW DEPTH OF COLD AIR AS WELL AS NEUTRAL-ALMOST ACYC LARGER SCALE LLVL FLOW WOULD SUG ANY LES WL BE ON THE LGT SIDE DESPITE ARRIVAL OF MUCH COLDER AIR BLO SHALLOW INVRN (GFS/NAM SHOW INVRN BASE TEMPS APRCHG -20C OVER THE NW BY LATE FRI). WL TEND TOWARD THE LO SIDE OF MOS GUIDANCE GIVEN HI STABILITY/SHALLOW NATURE OF ENCROACHING ARCTIC AIR. ON FRI NGT/SAT...UPR CONFLUENCE ZN PROGGED TO PUSH FAR ENUF S THAT DRY ARCTIC HI PRES CENTER DRIFTS OVER THE FA. WL DIMINISH POPS TO NO HIER THAN 30 NR LK SUP ON LATE FRI NGT/SAT TO REFLECT INCRSGLY HOSTILE CONDITIONS FOR LES. MADE A FEW CHGS TO THE SAT NGT/SUN PD TO REFLECT TREND TOWARD MORE AGGRESSIVE NRN BRANCH THAT WL AT LEAST DELAY THE PROGRESSION OF THE SW UPR TROF TO THE NE. IN GENERAL CUT POPS A BIT DURING THIS TIME WITH GREATER INFLUENCE OF DRIER NRN BRANCH. COORDINATED WITH GRB. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING E HALF LAKE SUPERIOR UNTIL 8 AM EST. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 747 PM CST THU JAN 11 2007 .DISCUSSION... UPDATED WIND CHILL ADVISORY TO SPREAD INTO A COUPLE MORE COUNTIES OVERNIGHT. TEMPERATURES ARE DROPPING QUICKLY AS SHALLOW ARCTIC AIRMASS SURGES TO THE SOUTH/EAST ALONG AND WEST OF THE MINNESOTA RIVER VALLEY. LIGHT SNOW CLIPPING THE FAR NORTHERN CWA...WITH A DUSTING TO NEAR AN INCH POSSIBLE AS WEAK SHORT WAVE MOVES/RIDES SOUTHWEST/NORTHEAST ORIENTED 25H JET MOVING ACROSS NORTHERN MN. ALONG WITH THIS FORCING...00Z RUC INDICATING BAND OF 600 MB FULL WIND FRONTOGENESIS MOVING ACROSS NORTHERN CWA THROUGH ABOUT 06Z AS WELL. UPPED THE POPS THIS REGION TO LIKELY AND ADDED LESS THAN 1 INCH ACCUMULATION POSSIBLE OVERNIGHT. APPEARS BEST CHANCE NORTH OF A LINE FROM NEAR KAXN-KLXL-KJMR. $$ .PREV DISCUSSION... /ISSUED 549 PM CST THU JAN 11 2007/ UPDATE...ADDED THE 00Z TAF DISCUSSION. PREV DISCUSSION... /ISSUED 334 PM CST THU JAN 11 2007/ DISCUSSION... COLD AIR POURING IN THIS AFTERNOON...WHICH HAS SURE BEEN SCARCE THIS SEASON. CURRENT SURFACE TEMPS UPSTREAM ARE COLDER THAN SHORT TERM MODEL TRENDS BUT LATEST RUC HAS BETTER HANDLE. MIN TEMPS SHOULD BE BELOW ZERO IN THE FAR NORTHWEST OR WEST COUNTIES. WIND CHILL VALUES WILL BE CLOSE TO CRITERIA...MAINLY LATE TONIGHT AND FRIDAY MORNING. WITH ABRUPT CHANGE...WILL GO AHEAD WITH AN ADVISORY FOR A FEW COUNTIES. WEAK WAVE STREAKING ENE ACROSS N CENTRAL SD WILL CAUSE SOME LIGHT SNOW IN FAR N CWA MAINLY THIS EVENING. OTHERWISE KIND OF IN A HOLDING PATTERN UNTIL SATURDAY NIGHT. GFS ENSEMBLE POPS OF LESS THAN 0.10 INCH KEEPING BEST CHANCES GENERALLY SOUTH OF AREA UNTIL SUNDAY OR SUNDAY NIGHT. THIS IS IS ABOUT WHAT WE CURRENTLY HAVE IN OUR GRIDS. ECMWF SHOWING A HINT OF A WEAK WAVE LIFTING OUT AHEAD OF SYSTEM LIFTING OUT ON SUNDAY WILL KEEP THE SMALL CHANCE SATURDAY NIGHT. ONCE AGAIN A SPLIT FLOW SITUATION WHICH HAS BEEN THE CASE MOST OF THE FALL AND EARLY WINTER..SO EXPECT A FAIRLY SHARP CUT OFF IN PRECIP AGAIN. LOOKS LIKE A COUPLE OF COLD NIGHTS AFTER THIS SYSTEM MOVES THROUGH..WITH MORE WIDESPREAD SUB ZERO MIN TEMPS. FAIRLY DRY NW FLOW SO SLIM CHANCE OF PRECIP...THERE IS A HINT OF A WAVE IN NW FLOW ABOUT TUESDAY OR WEDNESDAY BUT WILL LEAVE DRY FOR NOW. AVIATION...21Z RUC SHOWING SATURATION/UPGLIDE ON THE 280K THETA SURFACE ACROSS EAST CENTRAL AND SOUTH CENTRAL MN AND WEST CENTRAL WI. THIS CORRESPONDS PRETTY WELL WITH THE MVFR CEILINGS AT KMSP...KRNH AND KEAU. BELIEVE AS THE EVENING PROGRESS...KMSP WILL BREAK OUT OF THE LOW CEILINGS. BACK EDGE OF THE STRATUS LATE THIS AFTERNOON WAS PROGRESSING EAST AT 7 KNOTS. KEPT KEAU DOWN THROUGH LATE TOMORROW MORNING. TO THE WEST...MID LEVEL FRONTOGENESIS ACROSS THE CENTRAL DAKOTAS THROUGH NE MN WILL CONTINUE TO PROMOTE AN AREA OF FORCING THAT WILL SLIDE ACROSS THE NW CWA THIS EVENING. KEPT THE MENTION OF SNOW TO KAXN. INDICATED A SMALL PERIOD OF MVFR CEILINGS DURING THE EARLY MORNING HOURS AT KSTC AND KMSP AS THE ARCTIC AIR SURGES IN. BUFKIT PROFILE DATA FOR ALL OF THE MN TAF SITES INDICATES 20 TO 22 KNOT WIND GUSTS THROUGH MUCH OF THE TAF PERIOD WITH SUSTAINED WINDS NEAR 15 KNOTS. $$ && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY UNTIL 12 PM CST FRIDAY FOR CHIPPEWA-DOUGLAS- LAC QUI PARLE-POPE-STEVENS-SWIFT-TODD-YELLOW MEDICINE COUNTY(IES). WI...NONE. && $$ RAH/DWE mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 549 PM CST THU JAN 11 2007 .UPDATE...ADDED THE 00Z TAF DISCUSSION. && .PREV DISCUSSION... /ISSUED 334 PM CST THU JAN 11 2007/ DISCUSSION... COLD AIR POURING IN THIS AFTERNOON...WHICH HAS SURE BEEN SCARCE THIS SEASON. CURRENT SURFACE TEMPS UPSTREAM ARE COLDER THAN SHORT TERM MODEL TRENDS BUT LATEST RUC HAS BETTER HANDLE. MIN TEMPS SHOULD BE BELOW ZERO IN THE FAR NORTHWEST OR WEST COUNTIES. WIND CHILL VALUES WILL BE CLOSE TO CRITERIA...MAINLY LATE TONIGHT AND FRIDAY MORNING. WITH ABRUPT CHANGE...WILL GO AHEAD WITH AN ADVISORY FOR A FEW COUNTIES. WEAK WAVE STREAKING ENE ACROSS N CENTRAL SD WILL CAUSE SOME LIGHT SNOW IN FAR N CWA MAINLY THIS EVENING. OTHERWISE KIND OF IN A HOLDING PATTERN UNTIL SATURDAY NIGHT. GFS ENSEMBLE POPS OF LESS THAN 0.10 INCH KEEPING BEST CHANCES GENERALLY SOUTH OF AREA UNTIL SUNDAY OR SUNDAY NIGHT. THIS IS IS ABOUT WHAT WE CURRENTLY HAVE IN OUR GRIDS. ECMWF SHOWING A HINT OF A WEAK WAVE LIFTING OUT AHEAD OF SYSTEM LIFTING OUT ON SUNDAY WILL KEEP THE SMALL CHANCE SATURDAY NIGHT. ONCE AGAIN A SPLIT FLOW SITUATION WHICH HAS BEEN THE CASE MOST OF THE FALL AND EARLY WINTER..SO EXPECT A FAIRLY SHARP CUT OFF IN PRECIP AGAIN. LOOKS LIKE A COUPLE OF COLD NIGHTS AFTER THIS SYSTEM MOVES THROUGH..WITH MORE WIDESPREAD SUB ZERO MIN TEMPS. FAIRLY DRY NW FLOW SO SLIM CHANCE OF PRECIP...THERE IS A HINT OF A WAVE IN NW FLOW ABOUT TUESDAY OR WEDNESDAY BUT WILL LEAVE DRY FOR NOW. && .AVIATION...21Z RUC SHOWING SATURATION/UPGLIDE ON THE 280K THETA SURFACE ACROSS EAST CENTRAL AND SOUTH CENTRAL MN AND WEST CENTRAL WI. THIS CORRESPONDS PRETTY WELL WITH THE MVFR CEILINGS AT KMSP...KRNH AND KEAU. BELIEVE AS THE EVENING PROGRESS...KMSP WILL BREAK OUT OF THE LOW CEILINGS. BACK EDGE OF THE STRATUS LATE THIS AFTERNOON WAS PROGRESSING EAST AT 7 KNOTS. KEPT KEAU DOWN THROUGH LATE TOMORROW MORNING. TO THE WEST...MID LEVEL FRONTOGENESIS ACROSS THE CENTRAL DAKOTAS THROUGH NE MN WILL CONTINUE TO PROMOTE AN AREA OF FORCING THAT WILL SLIDE ACROSS THE NW CWA THIS EVENING. KEPT THE MENTION OF SNOW TO KAXN. INDICATED A SMALL PERIOD OF MVFR CEILINGS DURING THE EARLY MORNING HOURS AT KSTC AND KMSP AS THE ARCTIC AIR SURGES IN. BUFKIT PROFILE DATA FOR ALL OF THE MN TAF SITES INDICATES 20 TO 22 KNOT WIND GUSTS THROUGH MUCH OF THE TAF PERIOD WITH SUSTAINED WINDS NEAR 15 KNOTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 12 PM CST FRIDAY FOR CHIPPEWA-DOUGLAS-LAC QUI PARLE-POPE-STEVENS-SWIFT COUNTY(IES). WI...NONE. && $$ JPR/RAH mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1110 AM CST THU JAN 11 2007 .AVIATION... /18Z TAF CYCLE/...DIFFICULT FORECAST CEILING WISE...WITH POCKETS OF EITHER 1-1.5KFT CEILINGS OR 10KFT CEILINGS SCATTERED THROUGH THE AREA. HAVE GENERALLY GONE WITH THE TREND OF BRINGING A BRIEF BREAK IN THE LOW CLOUDS FOLLOWED BY ADDITIONAL /AND LOWER/ STRATUS DURING THE AFTERNOON...CONTINUING INTO OVERNIGHT...AS THE BRUNT OF THE LOW LEVEL COLD ADVECTION MOVES INTO THE AREA. WINDS WILL REMAIN FROM THE NORTHWEST AT 12 TO 15 KTS...WITH HIGHER GUSTS...THROUGH THE PERIOD. BROUGHT A CHANCE OF LIGHT SNOW SHOWERS INTO AXN AFTER 00Z TONIGHT...UNDER A REGION OF Q-VECTOR CONVERGENCE...HIGHER SREF POPS...AND LOWER CONDENSATION PRESSURE DEFICITS. THE ONLY OTHER TAF SITE THAT MAY SEE SOME PRECIPITATION LATE TONIGHT IS EAU...THAT BEING OF THE FLURRY OR FREEZING DRIZZLE VARIETY...BUT CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME TO INCLUDE. WILL PASS ON TO ONCOMING SHIFT...HOWEVER...FOR THE 00Z ISSUANCE. && .PREV DISCUSSION... /ISSUED 936 AM CST THU JAN 11 2007/ UPDATE... COLD FRONT HAS CLEARED MUCH OF THE FORECAST AREA...SANS THE EASTERN TWO TIERS OF COUNTIES IN WEST CENTRAL WISCONSIN. MANY LOCATIONS HAVE MET THEIR DAILY HIGHS ALREADY...WITH PLENTY OF COLD AIR ADVECTION MOVING IN BEHIND THE FRONT. HOURLY TEMPERATURE GRIDS FEATURE A STEADY TO FALLING TEMPERATURE TREND...MIRRORING THE TREND IN THE 06Z MAV. CLOUD COVER IS A BIT ERRATIC...WITH A FEW AREAS OF STRATOCU IN THE WESTERN FORECAST AREA...WITH SOME SCT TO OVC MID AND HIGH CLOUDS ELSEWHERE. LARGER AREA OF STRATOCU LOCATED IN SOUTHERN CANADA AND NORTHERN MINNESOTA/NORTHWEST WISCONSIN CURRENTLY SHOULD MAKE A SOUTHWARD SPREAD AS MAIN AREA OF LOW LEVEL COLD ADVECTION MOVES SOLIDLY INTO THE FORECAST AREA...WHICH SUPPORTS THE PARTLY TO MOSTLY CLOUDY FORECAST WE HAVE OUT THERE CURRENTLY. SLIGHT CHANCE OF SNOW DURING THE LATE AFTERNOON IN THE NORTHWEST ALSO LOOKS GOOD...WITH FAIRLY HIGH POPS FEATURED ON THE 09Z SREF...AND A PRONOUNCED AREA OF 500 TO 300 MB Q-VECTOR CONVERGENCE AND LOW CONDENSATION PRESSURE DEFICITS ON THE 280K SURFACE ON THE 12Z RUC/NAM. UPDATED PRODUCTS ALREADY AVAILABLE. PREV DISCUSSION... /ISSUED 411 AM CST THU JAN 11 2007/ DISCUSSION... SFC LOW PRESSURE ALONG THE CENTRAL MN/NW WI BORDER AT 10Z. PRESSURE FALLS INDICATE IT WILL MOVE ENE THIS MORNING AND DRAG COOLER AIR INTO THE WESTERN CWA. FIRST CONCERN WILL BE TEMP TRENDS THROUGHOUT THE DAY. TEMPS ROSE ACROSS THE EAST CENTRAL AND EASTERN CWA AROUND MIDNIGHT AND HAVE HELD FAIRLY STEADY SINCE AS AXIS OF WARMEST H85 TEMPS ENTERED THE EASTERN CWA. COLDER AIR FILTERING INTO THE NORTHWEST HAS BROUGHT A DOWNWARD TREND IN TEMPS PAST FEW HOURS AND EXPECT THIS TO CONTINUE THROUGH THE MORNING. HAVE INDICATED THIS IN THE GRIDS...WITH FAIRLY STEADY TEMPS ACROSS THE EAST HALF...WITH STEADY OR FALLING ACROSS THE WEST AS LOW PRESSURE MOVING NE INTO KANSAS HELPS TIGHTEN TEMP GRADIENT AND INHIBITS COLDER AIR ACROSS NRN PLAINS FROM BLASTING IN. NEXT CONCERN WILL BE LOW PRECIP CHANCES. HAVE KEPT SLIGHT CHANCE FOR SOME DRIZZLE AND FLURRIES ACROSS THE EXTREME SE AS MOISTURE RIDES UP INTO WISCONSIN AND IOWA AND INVERTED TROUGH DEVELOPS FROM NW MO THRU CENT WI. HAVE ADDED SLIGHT CHANCE FOR LIGHT SNOW LATE THIS AFTERNOON AND EARLY THIS EVENING ACROSS THE FAR NORTHWEST CWA AS MID LEVEL TEMP GRADIENT TIGHTENS BRINGING A BAND OF FRONTOGENESIS WITH INCREASED MID LEVEL MOISTURE AND Q VECTOR DIVERGENCE. WITH LIFT IN THE SNOW GROWTH ZONE SOME LIGHT SNOW MAY REACH THE GROUND...BUT BETTER MOISTURE IS JUST OUTSIDE THE CWA. HAVE ALSO INCLUDED FLURRIES THIS EVENING ACROSS THE ENTIRE AREA AS SOUNDINGS INDICATE MOIST INVERSION WITH LOW STRATUS AND SOME SYNOPTIC LIFT. COLDER AIR IS FINALLY ABLE TO WORK ACROSS THE ENTIRE AREA TOMORROW AS SFC LOW PRES PULLS OFF INTO QUEBEC...ALLOWING BAROCLINIC ZONE TO SAG SOUTHEAST. EXPECT VERY COLD BUT DRY CONDITIONS FRIDAY INTO SATURDAY. SATURDAY THROUGH MONDAY...SEEING A SLOWING TREND IN THE MODELS WITH THE EJECTION OF SOUTHWEST U.S. UPPER LEVEL LOW. THE MODELS HAVE BEEN TO FAST WITH THE EJECTION OF PREVIOUS SOUTHWEST U.S. LOWS THIS SEASON AND AM SEEING THIS AGAIN WITH THE UPCOMING SYSTEM. CANADIAN GLOBAL MODEL LOOKS TO BE THE MOST REASONABLE AT THIS POINT WITH A SOLUTION THAT REFLECTS THE TREND THAT THE GFS AND ECMWF ARE WORKING TOWARDS. CANADIAN INDICATES THAT UPPER LOW WILL CLOSE OFF OVER KS/NE BY 12Z MONDAY AND MAKE PROGRESS ENE ACROSS IA THROUGH MONDAY. THIS WOULD SET UP PRECIPITATION THAT MAY EFFECT SOUTHERN AND SOUTHEASTERN CWA SUNDAY NIGHT INTO MONDAY MORNING. SEVERAL CONCERNS FOR THIS TIME FRAME. FIRST IS SHORTWAVE TROF MOVING IN ON THE HEELS OF MAIN UPPER LOW EARLY SUNDAY. IF THIS FEATURE COMES TO FRUITION IT MAY WORK TO KICK THE LOW OUT A BIT FURTHER NORTH THAN CURRENTLY PROGGED AND SPREAD PRECIP FURTHER INTO THE CWA. ANOTHER CONCERN IS GFS AND CANADIAN DEPICTION OF NORTHERN STREAM SHORTWAVE TROF RIDING DOWN THROUGH CENTRAL CANADA AND INTERACTING WITH MAIN UPPER LOW IN CLOSE PROXIMITY TO THE CWA. A SIMILAR SCENARIO PLAYED OUT AT THE BEGINNING OF THE MONTH. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ KAT/MDB mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 936 AM CST THU JAN 11 2007 .UPDATE... COLD FRONT HAS CLEARED MUCH OF THE FORECAST AREA...SANS THE EASTERN TWO TIERS OF COUNTIES IN WEST CENTRAL WISCONSIN. MANY LOCATIONS HAVE MET THEIR DAILY HIGHS ALREADY...WITH PLENTY OF COLD AIR ADVECTION MOVING IN BEHIND THE FRONT. HOURLY TEMPERATURE GRIDS FEATURE A STEADY TO FALLING TEMPERATURE TREND...MIRRORING THE TREND IN THE 06Z MAV. CLOUD COVER IS A BIT ERRATIC...WITH A FEW AREAS OF STRATOCU IN THE WESTERN FORECAST AREA...WITH SOME SCT TO OVC MID AND HIGH CLOUDS ELSEWHERE. LARGER AREA OF STRATOCU LOCATED IN SOUTHERN CANADA AND NORTHERN MINNESOTA/NORTHWEST WISCONSIN CURRENTLY SHOULD MAKE A SOUTHWARD SPREAD AS MAIN AREA OF LOW LEVEL COLD ADVECTION MOVES SOLIDLY INTO THE FORECAST AREA...WHICH SUPPORTS THE PARTLY TO MOSTLY CLOUDY FORECAST WE HAVE OUT THERE CURRENTLY. SLIGHT CHANCE OF SNOW DURING THE LATE AFTERNOON IN THE NORTHWEST ALSO LOOKS GOOD...WITH FAIRLY HIGH POPS FEATURED ON THE 09Z SREF...AND A PRONOUNCED AREA OF 500 TO 300 MB Q-VECTOR CONVERGENCE AND LOW CONDENSATION PRESSURE DEFICITS ON THE 280K SURFACE ON THE 12Z RUC/NAM. UPDATED PRODUCTS ALREADY AVAILABLE. && .PREV DISCUSSION... /ISSUED 411 AM CST THU JAN 11 2007/ DISCUSSION... SFC LOW PRESSURE ALONG THE CENTRAL MN/NW WI BORDER AT 10Z. PRESSURE FALLS INDICATE IT WILL MOVE ENE THIS MORNING AND DRAG COOLER AIR INTO THE WESTERN CWA. FIRST CONCERN WILL BE TEMP TRENDS THROUGHOUT THE DAY. TEMPS ROSE ACROSS THE EAST CENTRAL AND EASTERN CWA AROUND MIDNIGHT AND HAVE HELD FAIRLY STEADY SINCE AS AXIS OF WARMEST H85 TEMPS ENTERED THE EASTERN CWA. COLDER AIR FILTERING INTO THE NORTHWEST HAS BROUGHT A DOWNWARD TREND IN TEMPS PAST FEW HOURS AND EXPECT THIS TO CONTINUE THROUGH THE MORNING. HAVE INDICATED THIS IN THE GRIDS...WITH FAIRLY STEADY TEMPS ACROSS THE EAST HALF...WITH STEADY OR FALLING ACROSS THE WEST AS LOW PRESSURE MOVING NE INTO KANSAS HELPS TIGHTEN TEMP GRADIENT AND INHIBITS COLDER AIR ACROSS NRN PLAINS FROM BLASTING IN. NEXT CONCERN WILL BE LOW PRECIP CHANCES. HAVE KEPT SLIGHT CHANCE FOR SOME DRIZZLE AND FLURRIES ACROSS THE EXTREME SE AS MOISTURE RIDES UP INTO WISCONSIN AND IOWA AND INVERTED TROUGH DEVELOPS FROM NW MO THRU CENT WI. HAVE ADDED SLIGHT CHANCE FOR LIGHT SNOW LATE THIS AFTERNOON AND EARLY THIS EVENING ACROSS THE FAR NORTHWEST CWA AS MID LEVEL TEMP GRADIENT TIGHTENS BRINGING A BAND OF FRONTOGENESIS WITH INCREASED MID LEVEL MOISTURE AND Q VECTOR DIVERGENCE. WITH LIFT IN THE SNOW GROWTH ZONE SOME LIGHT SNOW MAY REACH THE GROUND...BUT BETTER MOISTURE IS JUST OUTSIDE THE CWA. HAVE ALSO INCLUDED FLURRIES THIS EVENING ACROSS THE ENTIRE AREA AS SOUNDINGS INDICATE MOIST INVERSION WITH LOW STRATUS AND SOME SYNOPTIC LIFT. COLDER AIR IS FINALLY ABLE TO WORK ACROSS THE ENTIRE AREA TOMORROW AS SFC LOW PRES PULLS OFF INTO QUEBEC...ALLOWING BAROCLINIC ZONE TO SAG SOUTHEAST. EXPECT VERY COLD BUT DRY CONDITIONS FRIDAY INTO SATURDAY. SATURDAY THROUGH MONDAY...SEEING A SLOWING TREND IN THE MODELS WITH THE EJECTION OF SOUTHWEST U.S. UPPER LEVEL LOW. THE MODELS HAVE BEEN TO FAST WITH THE EJECTION OF PREVIOUS SOUTHWEST U.S. LOWS THIS SEASON AND AM SEEING THIS AGAIN WITH THE UPCOMING SYSTEM. CANADIAN GLOBAL MODEL LOOKS TO BE THE MOST REASONABLE AT THIS POINT WITH A SOLUTION THAT REFLECTS THE TREND THAT THE GFS AND ECMWF ARE WORKING TOWARDS. CANADIAN INDICATES THAT UPPER LOW WILL CLOSE OFF OVER KS/NE BY 12Z MONDAY AND MAKE PROGRESS ENE ACROSS IA THROUGH MONDAY. THIS WOULD SET UP PRECIPITATION THAT MAY EFFECT SOUTHERN AND SOUTHEASTERN CWA SUNDAY NIGHT INTO MONDAY MORNING. SEVERAL CONCERNS FOR THIS TIME FRAME. FIRST IS SHORTWAVE TROF MOVING IN ON THE HEELS OF MAIN UPPER LOW EARLY SUNDAY. IF THIS FEATURE COMES TO FRUITION IT MAY WORK TO KICK THE LOW OUT A BIT FURTHER NORTH THAN CURRENTLY PROGGED AND SPREAD PRECIP FURTHER INTO THE CWA. ANOTHER CONCERN IS GFS AND CANADIAN DEPICTION OF NORTHERN STREAM SHORTWAVE TROF RIDING DOWN THROUGH CENTRAL CANADA AND INTERACTING WITH MAIN UPPER LOW IN CLOSE PROXIMITY TO THE CWA. A SIMILAR SCENARIO PLAYED OUT AT THE BEGINNING OF THE MONTH. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ KAT/MDB mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 801 PM CST FRI JAN 12 2007 .UPDATE... HAVE GONE AHEAD AND ADDED BOND...FAYETTE AND CLINTON COUNTIES TO THE ICE STORM WARNING. THE RUC SEEMS TO HAVE THE BEST HANDLE ON THE SURFACE TEMPERATURES...AND IT MOVES THE FREEZING LINE INTO THESE COUNTIES BETWEEN 06-09Z. WHERE FREEZING RAIN HAS STARTED...MOST LOCATIONS HAVE RECEIVED AT LEAST A LIGHT GLAZE ON TREES AND SIGNS. PRECIPITATION TYPE IS MOSTLY SLEET NORTH OF A JEF-TROY MO-WHITE HALL LINE...WITH 1 INCH ACCUMULATIONS SLEET ACCUMULATION REPORTED ALREADY IN QUINCY AND NORTHERN LINCOLN COUNTY. BASED ON THE RADAR AND MODELS...STILL THINK THAT THE PRECIPITATION WILL FILL IN OVER THE SRN COUNTIES LATER TONIGHT...AND PRETTY MUCH THE ENTIRE CWA WILL SEE STEADY PRECIPITATION TONIGHT...SOME OF IT HEAVY AT TIMES. BRITT && .DISCUSSION... ICE STORM TO LAST THROUGH SUNDAY...SOME LOCATIONS MAY SEE GREATER THAN AN INCH OF ICE ACCUMULATION. EXTREMELY DANGEROUS SITUATION UNFOLDING ACROSS THE MIDWEST. COLD FRONT CONTINUES TO MOVE SOUTH THROUGH THE CWA WITH FREEZING TEMPERATURES FOLLOWING QUICK BEHIND. RAIN CHANGING TO FREEZING RAIN AND SLEET...WITH SOME MINOR ACCUMULATION OR GLAZING ALREADY REPORTED ACROSS CENTRAL AND NORTHEAST MISSOURI THIS AFTERNOON. FIRST OF THREE DISTURBANCES TO AFFECT THE REGION TAKING SHAPE...WITH LARGE PRECIPITATION SHIELD EXPANDING NORTHEAST FROM OKLAHOMA INTO SOUTHWEST MISSOURI. DECIDED TO UPDATE EVERYONE TO ICE STORM WARNING AROUND NOON TODAY...AS MODELS STILL ARE UNDERESTIMATING THE COLD AIR INTRUSION. UNBELIEVABLE...AT 130 PM KIRKSVILLE SITTING AT 18 DEGREES WITH A DEWPOINT OF 16 DEGREES AND NORTH WIND OF 11KTS. SHOULD SEE FREEZING LINE ENTER ST. LOUIS METROPOLITAN AREA DURING THIS EVENINGS RUSH HOUR..AS OFFICE TEMPERATURE IN WELDON SPRING IS ALREADY 36 DEGREES. STILL MAY NOT HAVE FREEZING LINE FAR ENOUGH SOUTH GIVEN UPSTREAM OBSERVATIONS BUT WILL LET LATER SHIFTS DETERMINE IF ICE WARNING SHOULD BE EXPANDED FURTHER SOUTH. SIGNIFICANT ICING UP TO ONE INCH WILL OCCUR TONIGHT...WITH THE GREATEST ACCUMULATIONS BETWEEN THE INTERSTATE 70 AND 44 CORRIDORS...INCLUDING THE ST. LOUIS METROPOLITAN AREA. GIVEN WHAT HAS HAPPENED IN THE PAST...EXPECT WIDESPREAD POWER OUTAGES. A LITTLE RELIEF ON SATURDAY...AS ONLY MINOR ADDITIONAL ICE ACCUMULATIONS ARE EXPECTED AS THIS FIRST WAVE EXITS..BUT TEMPERATURES WILL REMAIN BELOW FREEZING. BY SATURDAY NIGHT...THE SECOND WAVE ARRIVES WITH UP TO ANOTHER QUARTER INCH OF ICE POSSIBLE. THE THIRD WAVE ARRIVES SUNDAY WITH UP TO ANOTHER INCH OF ICE POSSIBLE ACROSS THE SAME PORTIONS OF THE CWA. ARCTIC AIR BUILDS IN BEHIND THIS FINAL WAVE WITH BITTERLY COLD TEMPERATURES EXPECTED. GIVEN POTENTIAL OF RAINFALL EXCEEDING FLASH FLOOD GUIDANCE SOUTH OF INTERSTATE 70 HAVE DECIDED TO ISSUE A FLOOD WATCH FOR SOUTHERN COUNTIES AND MENTION HEAVY RAIN/FREEZING RAIN IN ZONE FORECAST. ARCTIC AIR MASS BUILDS ACROSS REGION THROUGH THE EXTENDED WITH BELOW NORMAL TEMPERATURES EXPECTED. CVKING && .AVIATION... FOR THE 00Z TAFS...FIRST AND VERY SIGNIFCANT WAVE OF PCPN MOVING THRU THE FA NOW. WITH VERY LARGE WARM WEDGE OF AIR ALOFT...AND THIS IS INTERSECTING SHALLOW LAYER AND LEADING EDGE OF ARCTIC AIR AT THE SURFACE...SO LOOK FOR PROLONGED PERIOD OF FZRA TONIGHT. THIS FIRST WAVE IS EXPECTED TO EXIT EITHER LATE TONIGHT...FOR KUIN AND KCOU TERMINALS...OR EARLY SATURDAY MORNING FOR KSTL/KSUS TERMINALS. AFTER THIS...PCPN WILL BE VERY SPOTTY IN COVERAGE FOR REMAINDER OF THE VALID TAF PERIOD. LO CIGS OF MVFR AND IFR VARIETIES TO BOUNCE AROUND BETWEEN THE CATEGORIES FOR THE FIRST HALF OF TONIGHT DUE TO LIQUID PCPN...BUT SHOULD SETTLE MORE INTO THE IFR CATEGORY BY LATER TONIGHT AND SATURDAY...ESPECIALLY AFTER PCPN WINDS DOWN OR STOPS. PCPN WAVE NUMBER TWO WILL BE IMPACTING THE AREA LATE SATURDAY AFTERNOON AND NIGHT...BUT NOT BE AS HEAVY WITH THE QPF. TES && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLOOD WATCH FROM 1 AM CST SATURDAY THROUGH LATE SUNDAY NIGHT FOR CRAWFORD-IRON-MADISON-REYNOLDS-ST. FRANCOIS-STE. GENEVIEVE- WASHINGTON. ICE STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR AUDRAIN- BOONE-CALLAWAY-COLE-CRAWFORD-FRANKLIN-GASCONADE-JEFFERSON- KNOX-LEWIS-LINCOLN-MARION-MONITEAU-MONROE-MONTGOMERY-OSAGE- PIKE-RALLS-SHELBY-ST. CHARLES-ST. LOUIS-ST. LOUIS CITY- WARREN-WASHINGTON. IL...FLOOD WATCH FROM 1 AM CST SATURDAY THROUGH LATE SUNDAY NIGHT FOR RANDOLPH IL-WASHINGTON IL. ICE STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR ADAMS IL- BOND IL-BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL- JERSEY IL-MACOUPIN IL-MADISON IL-MONROE IL-MONTGOMERY IL- PIKE IL-ST. CLAIR IL. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 557 AM CST FRI JAN 12 2007 .DISCUSSION... TOUGH FCST FOR FIRST MID SHIFT. ALL IN ALL THE PREVIOUS FCST WAS TRENDING IN THE RIGHT DIRECTION WITH SOME SIGNIFICANT ICING EXPECTED ACROSS PORTIONS OF THE AREA OVER THE NEXT FEW DAYS THEN SLEET AND SOME SNOW ON THE TAIL END. THE MODELS STILL APPEAR TO BE HAVING GREAT DIFFICULTY WITH TIMING AND STRENGTH OF THE COLD AIR ASSOCIATED WITH THE ARCTIC FRONT. THE FRONT HAS MOVED THRU KUIN AND KCOU IN THE LAST HOUR OR SO AND THE FREEZING LINE LAGS THE FRONT BY ONLY 75-80 NM. VERY MILD AIR AHEAD OF THE FRONT WILL BE DISPLACED THROUGHOUT THE DAY BY THE COLD ARCTIC AIR AS IT MOVES SEWD WITH FALLING TEMPERATURES IN THE WAKE OF THE FRONT. THE FRONT SHOULD MOVE THROUGH THE ST LOUIS AREA 15-17Z AND EXIT THE CWA NEAR 00Z. THE RUC ACTUALLY HAS THE BEST HANDLE WITH THE SURFACE TEMPERATURES AND THEY WERE LARGELY FOLLOWED THRU 18Z OR SO THEN SOME EXTRAPOLATION WAS USED THRU 00Z TNGT. THE FREEZING LINE SHOULD RESIDE 25 NM OR SO NW OF STL AT 00Z. FROM THAT POINT ON THE EXACT PUSH OF COLD AIR IS MORE QUESTIONABLE AS MUCH OF THE GUIDANCE HAS THE FREEZING LINE WAVERING ON A NE/SW AXIS BI-SECTING OR JUST SE OF KSTL THRU SUNDAY AFTERNOON...IMPACTED BY SURFACE WAVES TRAVELLING ALONG THE FRONT. PCPN LOOKS LIKE IT SHOULD COME IN 3 DISTINCT WAVES WITH THIS PROLONGED STORM SYSTEM. MUCH OF THE PCPN WITH THE FIRST 2 ROUNDS WITH BE VIA LIFT ASSOCD WITH WAA/ISENTROPIC UPGLIDE MODULATED BY WK MID LVL DISTURBANCES. THE LAST ROUND WILL BE ASSOCD WITH THE LIFTING MID-UPR SYSTEM. PCPN WITH THE FIRST ROUND IS IN THE DEVELOPMENT STAGE ATTM AND WE SHOULD CONT TO SEE RAIN DEVELOP THROUGH THE MORNING BECOMING FAIRLY WIDESPREAD ACROSS THE SRN 2/3RDS OF THE CWA BY AFTERNOON. RAIN THROUGH THE EVENING SHOULD BE FOCUSED ACROSS MUCH IN THE SAME AREA GRADUALLY SHUNTING SE OVERNIGHT. THE NEXT ROUND SHOULD THEN GET GOING SATURDAY AFTERNOON AND THE FINAL ROUND ON SUNDAY INTO SUNDAY EVENING. WITH THE FREEZING AIR POISED JUST NW OF STL BY 00Z TNGT I UPGRADED THE WATCH TO A WINTER STORM WARNING FOR KCOU AND KUIN AREAS BEGINNING LATER THIS MORNING WITH FREEZING RAIN EXPECTED. KEEP THE WATCH GOING FOR THE CORIDOOR THRU THE STL METRO AREA DUE TO THE UNCERTAINTY WITH THE WAVERING FREEZING LINE. FOR THE ENTIRE 3 DAY EVENT COULD SEE ICE ACCUMULATIONS OF ONE-HALF TO THREE- QUARTERS OF AN INCH JUST SOUTH OF AN AXIS FROM KCOU TO KIJX. TREES AND POWER LINES WILL BE MOST VULNERABLE. STILL ANTICIPATING SOME DECENT 2-3 INCHES RAINS ACROSS SE MO AND SRN IL WHICH MAY PROMPT SOME SMALL STREAM AND RIVER FLOODING...AS SUCH HAVE KEPT THE ESF GOING. GLASS && .AVIATION... FOR THE 12Z TAFS...ARCTIC COLD FRONT HAS JUST PASSED THROUGH UIN AND COU AND SHOULD CONT MOVG SEWD THRU STL AND SUS ARND 18Z WITH THE SFC WND VEERING ARND TO THE NW BHND THE CDFNT. STRATUS CLOUDS ALONG WITH FOG HAVE DVLPD IN UIN AND COU BHND THE CDFNT. THIS LOW LVL CLOUDINESS SHOULD ADVCT SEWD INTO THE STL METRO AREA LTR THIS MRNG INTO THE AFTN HRS AND WILL FCST FALLING CEILINGS FOR STL AND SUS...DROPPING TO ARND 1000 FT BY AFTN. A SFC WV WILL DVLP ALNG THE SEWD MOVG CDFNT BRINGING RAIN TO THE CWA THIS AFTN AND TGT. LOOKING AT THE MDL FCST SOUNDINGS THE TEMPERATURE SHOULD DROP TO 32 DEGREES F OR BLW IN UIN AND COU THIS AFTN CHANGING THE RAIN TO FREEZING RAIN. THERE IS MORE UNCERTAINTY WHEN THE RAIN WILL CHANGE OVER TO FREEZING RAIN IN THE STL METRO AREA AS MDLS HAVE THE SFC TEMPERATURE DROPPING CLOSE TO THE FREEZING MARK TGT. WILL MENTION A TEMPO GRP OF FREEZING RAIN IN STL AND SUS LT TGT AT THE END OF THE TAF FCST PERIOD. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY EVENING FOR CRAWFORD-FRANKLIN-JEFFERSON-ST. CHARLES-ST. LOUIS-ST. LOUIS CITY-WASHINGTON. WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST SUNDAY NIGHT FOR GASCONADE-LINCOLN-MONTGOMERY-OSAGE-WARREN. WINTER STORM WARNING FROM 9 AM THIS MORNING TO MIDNIGHT CST SUNDAY NIGHT FOR AUDRAIN-BOONE-CALLAWAY-COLE-KNOX-LEWIS- MARION-MONITEAU-MONROE-PIKE-RALLS-SHELBY. IL...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY EVENING FOR CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL- MONROE IL-MONTGOMERY IL-ST. CLAIR IL. WINTER STORM WARNING FROM 9 AM THIS MORNING TO MIDNIGHT CST SUNDAY NIGHT FOR ADAMS IL-BROWN IL-PIKE IL. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 1023 AM PST FRI JAN 12 2007 .SYNOPSIS...A COLD UPPER LOW WILL SLOWLY MIGRATE ACROSS THE SOUTHERN GREAT BASIN AND MOJAVE DESERT TODAY AND SATURDAY. SNOW SHOWERS WILL OCCUR OVER MUCH OF THE REGION WITH HEAVIER SNOW BANDS OCCURRING OVER LINCOLN AND MOHAVE COUNTIES. TEMPERATURES WILL BE WELL BELOW NORMAL THROUGH THE WEEKEND AND INTO NEXT WEEK. && .UPDATED...MODELS INDICATE BEST FORCING NOW THROUGH 2 PM FOR LAS VEGAS VALLEY. RADAR DETECTING HEAVIEST SNOW BANDS IN SOUTHERN CLARK COUNTY AND CENTRAL MOHAVE COUNTY. MEASURABLE SNOW FOR THE LAS VEGAS VALLEY LOOKING MORE UNLIKELY BUT WILL KEEP SNOW ADVISORY UP AND CONCENTRATE WORDING MORE FOR SEARCHLIGHT...BOULDER CITY AND THE HIGHER TERRAIN OF NORTHEAST CLARK COUNTY THROUGH 6 PM. WHILE UPDATING WILL ISSUE A HARD FREEZE WARNING FOR ALL THE LOWER DESERTS OF SOUTHERN NEVADA...EASTERN CALIFORNIA AND NORTHWEST ARIZONA TONIGHT AND HARD FREEZE WATCH SATURDAY NIGHT INTO SUNDAY MORNING FOR THE SAME LOCATIONS. && .AVIATION...CLOUD BASES WILL LOWER THROUGH OUT THE REST OF THE MORNING AND AFTERNOON AND BRING CIGS IN THE LAS VEGAS VALLEY TO 7000 TO 6000 FT. SNOW SHOWERS ARE POSSIBLE BUT THEY WILL BE BE LIGHT AND BRING CIGS TO 4000 FT AND VIS TO 5 MILES AT WORST. HEAVIER SNOWS WILL LIKELY AFFECT THE MORMON MESA AND PEACH SPRINGS CORRIDORS WHERE A COUPLE OF INCHES OF SNOW MAY FALL. SKIES WILL CLEAR OUT AROUND MIDNIGHT AND BE THAT WAY THROUGH TOMORROW MORNING. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .SHORT TERM...SO MUCH TO TALK ABOUT THIS MORNING. WILL HIT THE HIGH POINTS HERE...THE INTERESTED READER MAY WANT TO REFER TO THE RNOWSWVEF...RNOSPSVEF...AND RNOHWOVEF PRODUCTS FOR MORE DETAILS. IN LINCOLN COUNTY...SIGNIFICANT SNOW BEGAN A FEW HOURS EARLIER THAN EXPECTED. THE SHERIFFS OFFICE IN PIOCHE REPORTED SIX INCHES ON THE GROUND AT 1 AM...SO UPGRADED THE SNOW ADVISORY TO A HEAVY SNOW WARNING. ALSO MOVED THE EXPIRATION TIME BACK FROM 4 AM SATURDAY TO 10 PM THIS EVENING AS IT APPEARS THE SIGNIFICANT SNOW WILL BE OVER BY THEN. IN CLARK COUNTY...THE COLD FRONT ROLLED THROUGH LAS VEGAS BETWEEN 2 AND 3 AM THIS MORNING. POST FRONTAL SNOW SHOWERS WERE FALLING AS FAR SOUTH AS INDIAN SPRINGS...BUT WERE NOT MAKING IT ACROSS THE MOUNTAINS INTO THE LAS VEGAS VALLEY. THE WINTER STORM WATCH IS A REAL CONUNDRUM. NAM...GFS...AND RUC MODELS ARE HINTING MORE STRONGLY AT A DRY SLOT AFFECTING THE INTERSTATE 15 CORRIDOR THIS AFTERNOON. HOWEVER...THEY ALSO STILL SHOW SOME UPWARD MOTION THROUGH A SATURATED LAYER IN OR NEAR THE -12C TO -18C "SWEET SPOT" FOR DENDRITIC SNOW CRYSTAL GROWTH. THERE IS MORE UNCERTAINTY THAN NORMAL WITH THIS FORECAST...BUT THE MIDPOINT OF THE POSSIBLE RANGE OF OUTCOMES FALLS INTO THE SNOW ADVISORY CATEGORY...SO UPGRADED THE WATCH TO AN ADVISORY. THE SNOW MAY BE MORE SHOWERY IN NATURE AS THE COLD UPPER LOW MOVES OVERHEAD. IN MOHAVE COUNTY...THE MODELS ALL SUGGEST BETTER MOISTURE AVAILABILITY SOUTHEAST OF THE POSSIBLE DRY SLOT. PREVIOUS SHIFT HAD ALREADY ISSUED A SNOW ADVISORY THERE...AND THIS STILL LOOKS GOOD. RESIDUAL MOISTURE WILL LINGER THROUGH MUCH OF SATURDAY...THEN THE BEST WINDOW OF OPPORTUNITY FOR CLEAR SKIES COMES ON SUNDAY MORNING. BIG QUESTION AFFECTING HOW COLD IT WILL GET IS WHETHER OR NOT THE NORTH WINDS WILL RELAX BY THEN. IF THE WINDS RELAX...TEMPERATURES WILL REALLY BOTTOM OUT...BUT IF THE WINDS ARE STILL BLOWING THE WIND CHILLS WILL BE WORSE...SO EITHER WAY IT WILL BE DANGEROUS TO UNSHELTERED FOLKS. SPS AND HWO HAVE BEEN/WILL BE ISSUED FOR THIS. THE MOST RECENT EVENTS SIMILAR TO THIS ONE AT MCCARRAN AIRPORT WERE A LOW OF 23F ON JANUARY 31 2002...AND A LOW OF 20F ON DECEMBER 22 1998. IF MCCARRAN REACHES 23F AS FORECAST ON SUNDAY MORNING...MANY PARTS OF THE VALLEY WILL BE IN THE TEENS. WRAP THOSE PIPES...DRIP THOSE FAUCETS...BRING THOSE PLANTS AND PETS INSIDE...ET CETERA. .LONG TERM...SHORTWAVE MOVING THROUGH THE CWA MONDAY WILL BRING A REINFORCING SHOT OF COOLER AIR...GUSTY WINDS DOWN THE COLORADO RIVER AND A FEW CLOUDS. EXPECT ANY PRECIPITATION TO REMAIN WELL EAST OF THE AREA AND WILL KEEP THE CURRENT ZERO POPS IN THE FORECAST. RIDGING WILL DEVELOP OVER THE AREA WEDNESDAY BUT EXPECT TEMPERATURES TO REMAIN BELOW NORMAL DUE TO LIGHT WINDS AND DAILY MORNING INVERSIONS. GFS IS SHOWING A LOW TO MOVE DOWN THE CA COAST AND EVENTUALLY PINCH OFF THE RIDGE AND FORM A REX BLOCK OVER THE WESTERN STATES. THE GFS/DGEX/ECMWF ARE HINTING AT THE LOW EVENTUALLY TURNING EAST AND PUSHING INTO THE CWA. RIGHT NOW THE MODELS ARE SHOWING LITTLE MOISTURE ASSOCIATED WITH THIS SYSTEM AND MAINLY JUST AN INCREASE IN CLOUDS. HAVE NOT INTRODUCED ANY POPS INTO THE FORECAST AND WILL WAIT FOR FUTURE MODEL RUNS. && .VEF WATCHES/WARNINGS/ADVISORIES... .NV...SNOW ADVISORY ZONE 15 THROUGH 6 PM TODAY. SNOW ADVISORY ZONES 16 20 AND 22 THROUGH 6 PM TODAY. .AZ...SNOW ADVISORY ZONES 1 AND 3 THROUGH 11 PM THIS EVENING. .CA...NONE. $$ PIERCE/JACQUES/MORGAN/GORELOW HTTP://WEATHER.GOV/LASVEGAS nv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 925 AM EST THU JAN 11 2007 .SHORT TERM /THIS AFTERNOON/...UPDATED SURFACE HIGH PRESSURE CENTERED OVER DELMARVA AND EASTERN VA WILL CONTINUE TO DOMINATE THE WEATHER ACROSS THE CAROLINAS THROUGH THIS AFTERNOON. KEPT MAX TEMPS THIS AFTERNOON A CATEGORY BELOW THE LATEST GUIDANCE WHICH HAS BEEN RUNNING A LITTLE WARM WITH THIS AIRMASS. SOUNDING EXTRAPOLATIONS ALSO SUGGEST STAYING ON THE COOLER SIDE OF GUIDANCE UNDER NEAR FULL SUN. MID TERM /TONIGHT THROUGH SATURDAY NIGHT/... UPPER RIDGE TO DOMINATE THE MID TERM. AT THE SFC...AN EAST-WEST RIDGE AXIS WILL EXTEND ACROSS OR IN THE VICINITY OF THE ILM CWA FROM THE HIGH CENTER LOCATED OFFSHORE FROM HAT. LATE TONIGHT AND FRIDAY...MODELS SHOW A KINK IN THE SFC PRESSURE FIELD OFF THE CAROLINA COASTS...AKA INVERTED SFC TROF. SOMEWHAT WEAK BUT MAY BE ENOUGH CONVERGENCE AND MOISTURE TO PRODUCE ONSHORE MOVEMENT OF LOW LEVEL CLOUDS. MODEL TIME HEIGHT PLOTS INDICATE VERY SHALLOW MOISTURE...EXTENDING ONLY UP TO 850MB. AS A RESULT...WILL REMOVE POPS ACROSS THE ILM CWA BUT LEAVE A SMALL CHANCE OVER THE ADJACENT OFFSHORE WATERS. SFC TROF TO DISSIPATE OR WASH OUT FRIDAY NIGHT. FOR SATURDAY...WITH STATIONARY FRONTAL BNDRY JUST NW OF THE ILM CWA...CULD OBSERVE DEBRIS CLOUDINESS ACROSS THE ILM CWA FROM PCPN MOVING ALONG IT. WILL KEEP SOME TYPE OF CLOUDINESS ACROSS THE REGION FRIDAY NIGHT THRU SAT NIGHT...BUT REMAIN PCPN FREE. TEMPS WILL DEPEND ON THE AMOUNT OF CLOUDINESS AND ONSHORE WINDS. OVERALL...WILL INDICATE A WARMING TREND WITH WIDESPREAD 70S LIKELY ON SATURDAY. JUST ANOTHER SUMMER...I MEAN WINTER WEEKEND SHAPING UP FOR THE ILM CWA. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... SUNDAY WILL BE NEARLY ANOTHER REPEAT OF SATURDAY...WITH WELL ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS DUE TO UPPER LEVEL RIDGING AND HIGH PRESSURE AT THE SURFACE WELL OFFSHORE. AN UPPER LEVEL TROUGH MOVING ACROSS THE SOUTHERN GREAT LAKES REGION AND AN ASSOCIATED SURFACE LOW MOVING INTO WESTERN NEW ENGLAND WILL ALLOW A COLD FRONT TO SWEEP ACROSS THE AREA ON MONDAY. THIS WILL RESULT IN A SMALL CHANCE OF SHOWERS MONDAY INTO MONDAY NIGHT. ALTHOUGH THE FRONT SHOULD BE OFFSHORE ON TUESDAY...THERE IS A SLIGHT CHANCE THAT SHOWERS COULD DEVELOP BEHIND THE FRONT AND AFFECT THE AREA. AN UNUSUALLY STRONG 1050 MB HIGH OVER THE CENTRAL PLAINS WILL BUILD OVER THE AREA LATE TUESDAY...AND PERSIST THROUGH WEDNESDAY. THIS WILL CAUSE 850 MB TEMPERATURES TO PLUMMET...FALLING TO AS LOW AS -10 CELSIUS BY WEDNESDAY IF THE LATEST GFS IS CORRECT. MEANWHILE...A WAVE OF LOW PRESSURE IS EXPECTED TO DEVELOP WELL OFFSHORE ALONG THE OLD FRONTAL BOUNDARY. THIS LOW COULD BRING SOME MOISTURE BACK INTO COASTAL AREAS SO WILL CARRY A SLIGHT CHANCE OF SHOWERS FOR THESE LOCATIONS AS A RESULT. IF THE LOW AND/OR ASSOCIATED MOISTURE ARE ANY CLOSER TO THE COAST...PRECIPITATION TYPE ISSUES COULD BE A CONCERN...ESPECIALLY FOR INLAND LOCATIONS TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION... VFR EXPECTED THROUGH THE TAF FORECAST PERIOD. HIGH PRESSURE SHIFTS EAST...ALLOWING NORTHEAST WINDS TO SHIFT TO SOUTHEAST BY LATE AFTERNOON. DID NOT PUT ANY FOG IN THE TAFS FOR THE OVERNIGHT HOURS...BUT WOULD NOT BE SURPRISED TO SEE 5-6 SM BR RIGHT AT SUNRISE WITH FAIRLY LIGHT WINDS ABOVE THE BOUNDARY LAYER. && .MARINE... SHORT TERM /THIS AFTERNOON/...UPDATED PLAN TO FOLLOW THE RUC THROUGH THE AFTERNOON. THIS SCENARIO HOLDS ONTO NORTHEASTERLY FLOW VERSUS VEERING IT DIRECTLY ONSHORE AS SOME OF THE OTHER SHORT RANGE MODELS INDICATE. FEEL WITH HIGH PRESSURE RIDGING IN FROM THE NORTH AND DEVELOPMENT OF A WEAK COASTAL TROUGH THAT THE RUC HAS A GOOD HANDLE ON THE SITUATION. OTHERWISE...NO MAJOR CHANGES WITH THE MORNING UPDATE. MID TERM /TONIGHT THROUGH SATURDAY NIGHT/... UPPER RIDGE AND ITS SFC COUNTERPART TO DOMINATE THE WX AND OCEAN CONDITIONS DURING THE MID TERM. THE CENTER OF THE SFC HIGH WILL DRIFT OFFSHORE FROM CAPE HATTERAS BY LATE FRIDAY. AM NOT ALL THAT CONFIDENT WITH THE IDEA AND SOLUTION FROM VARIOUS MODELS WITH REGARDS TO THE SHALLOW SFC COASTAL TROF AND ITS POSSIBLE MOVEMENT WESTWARD. FOR NOW HAVE INDICATED A LONGER PERIOD OF NE-E WINDS ON FRIDAY WITH VEERING TO SE AND S DIRECTIONS THERE-AFTER. UNLIKE THE NAM...THE GFS WANTS TO SUPPRESS THE SFC HIGH SOMEWHAT...RESULTING IN THE EAST TO WEST SFC RDG AXIS EXTENDING SOUTH OF THE ILM WATERS. THIS TO CAUSE A WESTERLY COMPONENT IN THE WINDS. WILL HOLD OFF WITH THE SW-W WINDS UNTIL MODEL TREND/CONSISTENCY BECOMES MORE PREVALENT. OVERALL...WIND SPEEDS 15 KT OR LESS. SEAS 4 FT OR LESS. LONG TERM /SUNDAY THROUGH MONDAY/... HIGH PRESSURE WILL REMAIN WELL OFFSHORE ON SUNDAY...WITH A SOUTHERLY FLOW PERSISTING ACROSS THE COASTAL WATERS. WINDS SHOULD INCREASE ON SUNDAY NIGHT AND MONDAY AHEAD OF AN APPROACHING COLD FRONT. SEAS COULD APPROACH SMALL CRAFT ADVISORY CRITERIA DUE TO THE STRENGTHENING SOUTHERLY FLOW AND GOOD FETCH ACROSS THE COASTAL WATERS. WINDS SHOULD SHIFT OFFSHORE LATE MONDAY AS THE COLD FRONT MOVES OFFSHORE. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...NONE. && $$ SHORT TERM...PFAFF AVIATION...DL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1033 AM CST THU JAN 11 2007 .UPDATE... NO CHANGES WERE MADE TO THE GRIDS. THE MAIN CONCERN IN THE FIRST PERIOD ARE THE GUSTY SOUTHERLY WINDS... AS THE FORECAST AREA REMAINS IN THE WARM SECTOR. A FEW LOCATIONS ACROSS WESTCENTRAL AND NORTHCENTRAL OKLAHOMA HAD INCREASED TO NEAR WIND ADVISORY CRITERIA. HOWEVER... LATEST RUC SUGGEST A WEAKENING IN THE PRESSURE GRADIENT AS THE SURFACE LOW MOVES ACROSS CENTRAL KANSAS. AS A RESULT... THE WINDS ARE EXPECTED TO WEAKEN SLIGHTLY AND STAY BELOW ADVISORY LEVELS. && .SHORT TERM... .LONG TERM... && .PREV DISCUSSION... /ISSUED 552 AM CST THU JAN 11 2007/ DISCUSSION...THE IMPENDING WINTER STORM HAS BEEN WELL ADVERTISED...BUT CHOSE TO RAMP UP TO A WINTER STORM WATCH AS SOME OF THE MESOSCALE DETAILS ARE BECOMING BETTER DEFINED. A FEW CYCLES AGO...THE MODELS TRENDED TOWARD A CLOSED UPPER LOW IN THE BASE OF THE WESTERN TROUGH...AND THIS HAS NOT CHANGED. THE UPPER LOW WAS LOCATED NEAR SEATTLE THIS MORNING AND SATELLITE SHOWED IT DROPPING ALMOST DUE SOUTH ALONG THE WEST COAST...WITH A COMPACT JET DIVING INTO THE BASE OF THE TROUGH. UPPER AIR ANALYSIS AT 00Z INDICATED STRONG COLD ADVECTION INTO THE BASE OF THE 700-500 MB TROUGH AT 00Z...AND MODELS ARE VERY SIMILAR IN TAKING THE CLOSED LOW TOWARD NORTHERN ARIZONA BY SATURDAY MORNING. A SIGNIFICANT CHANGE IN THE MODELS...HOWEVER...HAS BEEN TO DRAMATICALLY SPEED THE ARRIVAL OF SUB FREEZING TEMPERATURES ON FRIDAY. THIS HAD BEEN ANTICIPATED...BUT NOW IS APPEARING ALMOST A SURE THING AS THE LEADING EDGE OF CANADIAN AIR WAS ALREADY INTO NORTHEAST COLORADO AND SOUTHERN NEBRASKA EARLY THIS MORNING. EXPECT THE FRONT TO REACH NORTHERN OKLAHOMA BY EVENING AND I-44 AND BEYOND BY FRIDAY MORNING. THE MODELS MAY STILL NOT BE FAST ENOUGH...BUT THEY ARE STARTING TO CATCH ON. AND IN THE LATTER HALF OF THE WEEKEND THE NAM WAS PREFERRED AS IT KEEPS THE COLD AIR IN PLACE AND HAS A MORE REALISTIC PRESSURE PATTERN...NOT ALLOWING ANY STRONG CYCLOGENESIS OR SURFACE TROUGHS TO OCCUR IN THE COLD AIR AS THE GFS HAS BEEN DOING. BOTH THE NAM AND GFS PRODUCE A LOT OF LIQUID PRECIP WHICH COINCIDES WITH SUB FREEZING TEMPERATURES AT THE SURFACE. CONFIDENCE IS INCREASING TOWARD A MAJOR ICE STORM TO AFFECT THE REGION...WITH EVERYONE SEEING AT LEAST SOME FREEZING DRIZZLE AND FREEZING RAIN...BUT WITH SOME AREAS SEEING MUCH MORE. THE HEAVIER ICE ACCUMULATIONS APPEAR MOST LIKELY ALONG AND EITHER SIDE OF INTERSTATE 44...AFFECTING THE METRO AREAS FROM WICHITA FALLS TO LAWTON TO OKLAHOMA CITY...AND INCLUDING SOUTHERN OKLAHOMA. EXPECTING THE HEAVIER PRECIP TO COME IN TWO WAVES...THE FIRST ON FRIDAY INTO FRIDAY NIGHT WITH A SUB TROPICAL JET EJECTING OUT OF NORTHERN MEXICO. THIS WILL LEAD TO AN EXTENSIVE PERIOD OF ENHANCED WARM ADVECTION ALOFT IN THE RIGHT REAR OF THE JET. THE SECOND EVENT WILL COVER A LARGER AREA AS THE MAIN UPPER WAVE EJECTS FROM THE ROCKIES. THROUGHOUT ALL THIS...THERE WILL BE DEEPER MOISTURE AND POTENTIAL FOR CONVECTIVE ENHANCEMENT ALONG THE RED RIVER UP THROUGH CENTRAL OKLAHOMA. TEMPERATURES WILL BE CLOSER TO FREEZING ALONG THE RED RIVER IN SOUTHERN OKLAHOMA...BUT MUCH COLDER TOWARD WESTERN NORTH TEXAS AND CENTRAL OKLAHOMA. WILL HOPE THAT THE HEAVIEST AMOUNTS END UP NEAR OR SOUTH OF THE FREEZING LINE...BUT IF A WORST CASE SCENARIO WERE TO OCCUR THERE COULD BE A SWATH OF ICE ACCUMULATION MEASURED IN INCHES. IN ADDITION...WINDS WILL BECOME GUSTY ON SUNDAY...AND COULD BRING DOWN TREE LIMBS AND POWER LINES WEIGHTED DOWN BY THE ICE. NO CHANGES MADE BEYOND SUNDAY. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 63 40 40 22 / 10 40 70 70 HOBART OK 70 41 41 22 / 10 20 40 50 WICHITA FALLS TX 71 59 59 26 / 10 30 80 80 GAGE OK 66 28 28 17 / 0 10 30 40 PONCA CITY OK 59 35 35 19 / 10 30 50 50 DURANT OK 60 60 62 34 / 20 40 80 80 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR OKZ004>047-050-051. TX...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR TXZ083>090. && $$ 67/23 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 913 PM CST FRI JAN 12 2007 .UPDATE... UPDATE IS MAINLY FOR EXTENDING THE ICE STORM WARNING ONE SET OF COUNTIES FURTHER SOUTH WHICH INCLUDES THE NORTHERN CONCHO VALLEY AND NORTHERN HEARTLAND. ARCTIC COLD FRONT IS NOW LOCATED SOUTH OF A KBWD TO KSJT LINE...AND TEMPERATURES HAVE FALLEN INTO THE MID TO UPPER 20S ACROSS THE BIG COUNTRY. STRONG SUB TROPICAL JET WITH DISTURBANCES MOVING NORTHEAST SHOULD KEEP SCATTERED AREAS OF PCPN GOING THROUGH TONIGHT. LATEST MODEL RUN INDICATING MAIN UPPER LEVEL TROF LIFTING NORTHEAST ACROSS AREA SATURDAY NIGHT AND SUNDAY...LEADING TO NEXT ROUND OF FZRA AND POSSIBLE SIGNIFICANT ICE ACCUMULATIONS ACROSS THE NORTHERN HALF OF WEST CENTRAL TEXAS. && .PREV DISCUSSION... /ISSUED 618 PM CST FRI JAN 12 2007/ AVIATION... WIDESPREAD PCPN CONTINUES ACROSS THE EASTERN 2/3 WEST CENTRAL TEXAS. THE PCPN IS IN THE FORM OF FZRA ACROSS THE NORTHERN BIG COUNTRY. THE ARCTIC COLD FRONT IS LOCATED NEAR A KDFW-KBWD-KSJT LINE. THE FRONT WILL CONTINUE TO MOVE SOUTH DURING TONIGHT AND SATURDAY. THERE MAY BE A BREAK IN THE PCPN LATER TONIGHT...AND THEN BECOME WIDESPREAD ON SATURDAY AS A STRONG UPPER LEVEL SYSTEM MOVES ACROSS THE ARCTIC AIRMASS OVER NORTHERN AND CENTRAL TEXAS. THE PCPN TYPE WILL REMAIN FZRA ACROSS THE BIG COUNTRY THROUGH SATURDAY...WITH POSSIBLE FZRA ALONG A KBWD TO KSJT TO MERTZON LINE ON SATURDAY. IFR CIGS OF BLO OVC010 EXPECTED ACROSS THE MUCH OF WEST CENTRAL TEXAS THROUGH 14/00Z. PREV DISCUSSION... /ISSUED 557 PM CST FRI JAN 12 2007/ UPDATE...UPDATE ALREADY ISSUED TO ACCOUNT FOR TEMEPRATURE TRENDS ALREADY COOLER THAN GRIDS. FREEZING LINE NOW APPROACHING KABI WITH SOME TROUBLE SPOTS ACROSS HASKELL AND THROCKMORTON COUNTIES ALREADY OCCURING. ANTICIPATE THAT WE MAY HAVE TO PUSH THE WARNING ONE MORE ROW OF COUNTIES TO THE SOUTH THIS EVENING...BUT WOULD LIKE TO LOOK AT A LITTLE MORE INFORMATION BEFORE MAKING THAT FINAL CALL THIS EVENING. BRAZZELL PREV DISCUSSION... /ISSUED 310 PM CST FRI JAN 12 2007/ WINTER RETURNS WITH A VENGEANCE... SHORT TERM... A DIFFICULT FORECAST OVER THE NEXT FEW DAYS AS AN ARCTIC AIR MASS MOVES SOUTH ACROSS THE CWA. THE CHALLENGES WITH THIS FORECAST ARE HOW FAR SOUTH THE FREEZING PRECIPITATION WILL OCCUR AND HOW MUCH WILL ACCUMULATE. THERE IS A GOOD CHANCE FOR PRECIPITATION THIS WEEKEND BUT HOW FAR SOUTH THE ARCTIC FRONT PROGRESSES BEFORE IT STALLS WILL BE THE DETERMINING FACTOR. THE MODELS HAVE BEEN TOO SLOW WITH THE SOUTHWARD PROGRESSION OF THE ARCTIC FRONT...WITH THE RUC/NAM MODELS APPEARING TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT. THE FRONT IS ALREADY ALONG THE I-20 CORRIDOR AND TEMPERATURES ARE FALLING. TEMPERATURES ARE AT OR BELOW FREEZING ACROSS THE NORTHERN BIG COUNTRY AND THE RAIN THAT IS FALLING ACROSS THE BIG COUNTRY WILL CHANGE OVER TO FREEZING RAIN AFTER SUNSET. WITH THE STRONGEST LIFT ON SATURDAY NIGHT AND SUNDAY MORNING EXPECT THE LARGEST FREEZING RAIN ACCUMULATIONS TO OCCUR DURING THIS TIME PERIOD. ACROSS THE BIG COUNTRY IN GENERAL EXPECT ICE ACCUMULATIONS TONIGHT THROUGH SUNDAY TO BE BETWEEN ONE QUARTER TO ONE HALF OF INCH...SOME ISOLATED AREAS COULD SEE ICE ACCUMULATIONS UP TO ONE INCH. ACROSS THE HEARTLAND AND CONCHO VALLEY EXPECT LESS ICE ACCUMULATION TO OCCUR WITH TOTALS SATURDAY NIGHT THROUGH SUNDAY LESS THAN ONE QUARTER OF AN INCH. TEMPERATURES WILL NOT REBOUND QUICKLY SO WHAT ICE THAT ACCUMULATES WILL STAY AROUND THROUGH THE EARLY PART OF NEXT WEEK. LONG TERM... MODELS DIVERGE THE BEGINNING OF THE WEEK WITH THE GFS SHOWING AN UPPER RIDGE BUILDING INTO THE WEST COAST WITH THE MAIN LOBE OF THE UPPER TROUGH DIGGING FROM THE CENTRAL PLAINS INTO THE SOUTHWEST UNDERCUTTING THE ADVANCING WEST COAST RIDGE. GFS EVENTUALLY MERGES THIS FEATURE WITH A WEST COAST TROUGH MOVING SOUTH ALONG THE PACIFIC COAST AND RETROGRADES THE ENTIRE PACKAGE. PREFER THE NAM THAT HAS THE UPPER LEVEL TROUGH AXIS MOVING EAST OF THE AREA LATE SUNDAY AND THE WEST COAST RIDGE BUILDING EAST INTO THE WESTERN STATES. WITH THIS SCENARIO...PRECIPITATION ENDS QUICKER OVER THE FORECAST AREA WITH THE PRECIPITATION SHIELD MOVING EAST AHEAD OF THE UPPER TROUGH BY MONDAY AFTERNOON. TEMPERATURES WILL CLIMB SLOWLY THROUGH THE END OF THE WEEK TO AROUND SEASONAL NORMALS BY THE COMING WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 26 29 28 31 / 70 60 70 70 SAN ANGELO 31 36 32 40 / 60 60 70 70 JUNCTION 45 47 39 46 / 60 70 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR CALLAHAN-FISHER- HASKELL-JONES-NOLAN-SHACKELFORD-TAYLOR-THROCKMORTON. WINTER STORM WATCH FROM 6 AM CST SATURDAY THROUGH SUNDAY AFTERNOON FOR CONCHO-IRION-MCCULLOCH-SAN SABA-TOM GREEN. ICE STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR BROWN-COKE-COLEMAN-RUNNELS-STERLING. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 618 PM CST FRI JAN 12 2007 .AVIATION... WIDESPREAD PCPN CONTINUES ACROSS THE EASTERN 2/3 WEST CENTRAL TEXAS. THE PCPN IS IN THE FORM OF FZRA ACROSS THE NORTHERN BIG COUNTRY. THE ARCTIC COLD FRONT IS LOCATED NEAR A KDFW-KBWD-KSJT LINE. THE FRONT WILL CONTINUE TO MOVE SOUTH DURING TONIGHT AND SATURDAY. THERE MAY BE A BREAK IN THE PCPN LATER TONIGHT...AND THEN BECOME WIDESPREAD ON SATURDAY AS A STRONG UPPER LEVEL SYSTEM MOVES ACROSS THE ARCTIC AIRMASS OVER NORTHERN AND CENTRAL TEXAS. THE PCPN TYPE WILL REMAIN FZRA ACROSS THE BIG COUNTRY THROUGH SATURDAY...WITH POSSIBLE FZRA ALONG A KBWD TO KSJT TO MERTZON LINE ON SATURDAY. IFR CIGS OF BLO OVC010 EXPECTED ACROSS THE MUCH OF WEST CENTRAL TEXAS THROUGH 14/00Z. && .PREV DISCUSSION... /ISSUED 557 PM CST FRI JAN 12 2007/ UPDATE...UPDATE ALREADY ISSUED TO ACCOUNT FOR TEMEPRATURE TRENDS ALREADY COOLER THAN GRIDS. FREEZING LINE NOW APPROACHING KABI WITH SOME TROUBLE SPOTS ACROSS HASKELL AND THROCKMORTON COUNTIES ALREADY OCCURING. ANTICIPATE THAT WE MAY HAVE TO PUSH THE WARNING ONE MORE ROW OF COUNTIES TO THE SOUTH THIS EVENING...BUT WOULD LIKE TO LOOK AT A LITTLE MORE INFORMATION BEFORE MAKING THAT FINAL CALL THIS EVENING. BRAZZELL PREV DISCUSSION... /ISSUED 310 PM CST FRI JAN 12 2007/ .WINTER RETURNS WITH A VENGEANCE... SHORT TERM... A DIFFICULT FORECAST OVER THE NEXT FEW DAYS AS AN ARCTIC AIR MASS MOVES SOUTH ACROSS THE CWA. THE CHALLENGES WITH THIS FORECAST ARE HOW FAR SOUTH THE FREEZING PRECIPITATION WILL OCCUR AND HOW MUCH WILL ACCUMULATE. THERE IS A GOOD CHANCE FOR PRECIPITATION THIS WEEKEND BUT HOW FAR SOUTH THE ARCTIC FRONT PROGRESSES BEFORE IT STALLS WILL BE THE DETERMINING FACTOR. THE MODELS HAVE BEEN TOO SLOW WITH THE SOUTHWARD PROGRESSION OF THE ARCTIC FRONT...WITH THE RUC/NAM MODELS APPEARING TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT. THE FRONT IS ALREADY ALONG THE I-20 CORRIDOR AND TEMPERATURES ARE FALLING. TEMPERATURES ARE AT OR BELOW FREEZING ACROSS THE NORTHERN BIG COUNTRY AND THE RAIN THAT IS FALLING ACROSS THE BIG COUNTRY WILL CHANGE OVER TO FREEZING RAIN AFTER SUNSET. WITH THE STRONGEST LIFT ON SATURDAY NIGHT AND SUNDAY MORNING EXPECT THE LARGEST FREEZING RAIN ACCUMULATIONS TO OCCUR DURING THIS TIME PERIOD. ACROSS THE BIG COUNTRY IN GENERAL EXPECT ICE ACCUMULATIONS TONIGHT THROUGH SUNDAY TO BE BETWEEN ONE QUARTER TO ONE HALF OF INCH...SOME ISOLATED AREAS COULD SEE ICE ACCUMULATIONS UP TO ONE INCH. ACROSS THE HEARTLAND AND CONCHO VALLEY EXPECT LESS ICE ACCUMULATION TO OCCUR WITH TOTALS SATURDAY NIGHT THROUGH SUNDAY LESS THAN ONE QUARTER OF AN INCH. TEMPERATURES WILL NOT REBOUND QUICKLY SO WHAT ICE THAT ACCUMULATES WILL STAY AROUND THROUGH THE EARLY PART OF NEXT WEEK. LONG TERM... MODELS DIVERGE THE BEGINNING OF THE WEEK WITH THE GFS SHOWING AN UPPER RIDGE BUILDING INTO THE WEST COAST WITH THE MAIN LOBE OF THE UPPER TROUGH DIGGING FROM THE CENTRAL PLAINS INTO THE SOUTHWEST UNDERCUTTING THE ADVANCING WEST COAST RIDGE. GFS EVENTUALLY MERGES THIS FEATURE WITH A WEST COAST TROUGH MOVING SOUTH ALONG THE PACIFIC COAST AND RETROGRADES THE ENTIRE PACKAGE. PREFER THE NAM THAT HAS THE UPPER LEVEL TROUGH AXIS MOVING EAST OF THE AREA LATE SUNDAY AND THE WEST COAST RIDGE BUILDING EAST INTO THE WESTERN STATES. WITH THIS SCENARIO...PRECIPITATION ENDS QUICKER OVER THE FORECAST AREA WITH THE PRECIPITATION SHIELD MOVING EAST AHEAD OF THE UPPER TROUGH BY MONDAY AFTERNOON. TEMPERATURES WILL CLIMB SLOWLY THROUGH THE END OF THE WEEK TO AROUND SEASONAL NORMALS BY THE COMING WEEKEND. .PRELIMINARY POINT TEMPS/POPS... ABILENE 26 29 28 31 / 70 60 70 70 SAN ANGELO 31 36 32 40 / 60 60 70 70 JUNCTION 45 47 39 46 / 60 70 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR CALLAHAN-FISHER- HASKELL-JONES-NOLAN-SHACKELFORD-TAYLOR-THROCKMORTON. WINTER STORM WATCH FROM 6 AM CST SATURDAY THROUGH SUNDAY AFTERNOON FOR CONCHO-IRION-MCCULLOCH-SAN SABA-TOM GREEN. WINTER STORM WATCH FROM MIDNIGHT CST TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-COKE-COLEMAN-RUNNELS-STERLING. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 557 PM CST FRI JAN 12 2007 .UPDATE...UPDATE ALREADY ISSUED TO ACCOUNT FOR TEMEPRATURE TRENDS ALREADY COOLER THAN GRIDS. FREEZING LINE NOW APPROACHING KABI WITH SOME TROUBLE SPOTS ACROSS HASKELL AND THROCKMORTON COUNTIES ALREADY OCCURING. ANTICIPATE THAT WE MAY HAVE TO PUSH THE WARNING ONE MORE ROW OF COUNTIES TO THE SOUTH THIS EVENING...BUT WOULD LIKE TO LOOK AT A LITTLE MORE INFORMATION BEFORE MAKING THAT FINAL CALL THIS EVENING. BRAZZELL && .PREV DISCUSSION... /ISSUED 310 PM CST FRI JAN 12 2007/ ..WINTER RETURNS WITH A VENGEANCE... SHORT TERM... A DIFFICULT FORECAST OVER THE NEXT FEW DAYS AS AN ARCTIC AIR MASS MOVES SOUTH ACROSS THE CWA. THE CHALLENGES WITH THIS FORECAST ARE HOW FAR SOUTH THE FREEZING PRECIPITATION WILL OCCUR AND HOW MUCH WILL ACCUMULATE. THERE IS A GOOD CHANCE FOR PRECIPITATION THIS WEEKEND BUT HOW FAR SOUTH THE ARCTIC FRONT PROGRESSES BEFORE IT STALLS WILL BE THE DETERMINING FACTOR. THE MODELS HAVE BEEN TOO SLOW WITH THE SOUTHWARD PROGRESSION OF THE ARCTIC FRONT...WITH THE RUC/NAM MODELS APPEARING TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT. THE FRONT IS ALREADY ALONG THE I-20 CORRIDOR AND TEMPERATURES ARE FALLING. TEMPERATURES ARE AT OR BELOW FREEZING ACROSS THE NORTHERN BIG COUNTRY AND THE RAIN THAT IS FALLING ACROSS THE BIG COUNTRY WILL CHANGE OVER TO FREEZING RAIN AFTER SUNSET. WITH THE STRONGEST LIFT ON SATURDAY NIGHT AND SUNDAY MORNING EXPECT THE LARGEST FREEZING RAIN ACCUMULATIONS TO OCCUR DURING THIS TIME PERIOD. ACROSS THE BIG COUNTRY IN GENERAL EXPECT ICE ACCUMULATIONS TONIGHT THROUGH SUNDAY TO BE BETWEEN ONE QUARTER TO ONE HALF OF INCH...SOME ISOLATED AREAS COULD SEE ICE ACCUMULATIONS UP TO ONE INCH. ACROSS THE HEARTLAND AND CONCHO VALLEY EXPECT LESS ICE ACCUMULATION TO OCCUR WITH TOTALS SATURDAY NIGHT THROUGH SUNDAY LESS THAN ONE QUARTER OF AN INCH. TEMPERATURES WILL NOT REBOUND QUICKLY SO WHAT ICE THAT ACCUMULATES WILL STAY AROUND THROUGH THE EARLY PART OF NEXT WEEK. LONG TERM... MODELS DIVERGE THE BEGINNING OF THE WEEK WITH THE GFS SHOWING AN UPPER RIDGE BUILDING INTO THE WEST COAST WITH THE MAIN LOBE OF THE UPPER TROUGH DIGGING FROM THE CENTRAL PLAINS INTO THE SOUTHWEST UNDERCUTTING THE ADVANCING WEST COAST RIDGE. GFS EVENTUALLY MERGES THIS FEATURE WITH A WEST COAST TROUGH MOVING SOUTH ALONG THE PACIFIC COAST AND RETROGRADES THE ENTIRE PACKAGE. PREFER THE NAM THAT HAS THE UPPER LEVEL TROUGH AXIS MOVING EAST OF THE AREA LATE SUNDAY AND THE WEST COAST RIDGE BUILDING EAST INTO THE WESTERN STATES. WITH THIS SCENARIO...PRECIPITATION ENDS QUICKER OVER THE FORECAST AREA WITH THE PRECIPITATION SHIELD MOVING EAST AHEAD OF THE UPPER TROUGH BY MONDAY AFTERNOON. TEMPERATURES WILL CLIMB SLOWLY THROUGH THE END OF THE WEEK TO AROUND SEASONAL NORMALS BY THE COMING WEEKEND. PRELIMINARY POINT TEMPS/POPS... ABILENE 27 32 30 31 / 70 60 70 70 SAN ANGELO 31 37 32 40 / 60 60 70 70 JUNCTION 48 53 39 46 / 60 70 70 70 SJT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR CALLAHAN-FISHER- JONES-NOLAN-SHACKELFORD-TAYLOR. WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON FOR CONCHO-IRION-MCCULLOCH-SAN SABA-TOM GREEN. WINTER STORM WATCH FROM MIDNIGHT CST TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-COKE-COLEMAN-RUNNELS-STERLING. ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR HASKELL-THROCKMORTON. $$ && .PRELIMINARY POINT TEMPS/POPS... ABILENE 26 29 28 31 / 70 60 70 70 SAN ANGELO 31 36 32 40 / 60 60 70 70 JUNCTION 45 47 39 46 / 60 70 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR CALLAHAN-FISHER- JONES-NOLAN-SHACKELFORD-TAYLOR. WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON FOR CONCHO-IRION-MCCULLOCH-SAN SABA-TOM GREEN. WINTER STORM WATCH FROM MIDNIGHT CST TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-COKE-COLEMAN-RUNNELS-STERLING. ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR HASKELL-THROCKMORTON. && $$ 27/27 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 310 PM CST FRI JAN 12 2007 ...WINTER RETURNS WITH A VENGEANCE... SHORT TERM... A DIFFICULT FORECAST OVER THE NEXT FEW DAYS AS AN ARCTIC AIR MASS MOVES SOUTH ACROSS THE CWA. THE CHALLENGES WITH THIS FORECAST ARE HOW FAR SOUTH THE FREEZING PRECIPITATION WILL OCCUR AND HOW MUCH WILL ACCUMULATE. THERE IS A GOOD CHANCE FOR PRECIPITATION THIS WEEKEND BUT HOW FAR SOUTH THE ARCTIC FRONT PROGRESSES BEFORE IT STALLS WILL BE THE DETERMINING FACTOR. THE MODELS HAVE BEEN TOO SLOW WITH THE SOUTHWARD PROGRESSION OF THE ARCTIC FRONT...WITH THE RUC/NAM MODELS APPEARING TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT. THE FRONT IS ALREADY ALONG THE I-20 CORRIDOR AND TEMPERATURES ARE FALLING. TEMPERATURES ARE AT OR BELOW FREEZING ACROSS THE NORTHERN BIG COUNTRY AND THE RAIN THAT IS FALLING ACROSS THE BIG COUNTRY WILL CHANGE OVER TO FREEZING RAIN AFTER SUNSET. WITH THE STRONGEST LIFT ON SATURDAY NIGHT AND SUNDAY MORNING EXPECT THE LARGEST FREEZING RAIN ACCUMULATIONS TO OCCUR DURING THIS TIME PERIOD. ACROSS THE BIG COUNTRY IN GENERAL EXPECT ICE ACCUMULATIONS TONIGHT THROUGH SUNDAY TO BE BETWEEN ONE QUARTER TO ONE HALF OF INCH...SOME ISOLATED AREAS COULD SEE ICE ACCUMULATIONS UP TO ONE INCH. ACROSS THE HEARTLAND AND CONCHO VALLEY EXPECT LESS ICE ACCUMULATION TO OCCUR WITH TOTALS SATURDAY NIGHT THROUGH SUNDAY LESS THAN ONE QUARTER OF AN INCH. TEMPERATURES WILL NOT REBOUND QUICKLY SO WHAT ICE THAT ACCUMULATES WILL STAY AROUND THROUGH THE EARLY PART OF NEXT WEEK. LONG TERM... MODELS DIVERGE THE BEGINNING OF THE WEEK WITH THE GFS SHOWING AN UPPER RIDGE BUILDING INTO THE WEST COAST WITH THE MAIN LOBE OF THE UPPER TROUGH DIGGING FROM THE CENTRAL PLAINS INTO THE SOUTHWEST UNDERCUTTING THE ADVANCING WEST COAST RIDGE. GFS EVENTUALLY MERGES THIS FEATURE WITH A WEST COAST TROUGH MOVING SOUTH ALONG THE PACIFIC COAST AND RETROGRADES THE ENTIRE PACKAGE. PREFER THE NAM THAT HAS THE UPPER LEVEL TROUGH AXIS MOVING EAST OF THE AREA LATE SUNDAY AND THE WEST COAST RIDGE BUILDING EAST INTO THE WESTERN STATES. WITH THIS SCENARIO...PRECIPITATION ENDS QUICKER OVER THE FORECAST AREA WITH THE PRECIPITATION SHIELD MOVING EAST AHEAD OF THE UPPER TROUGH BY MONDAY AFTERNOON. TEMPERATURES WILL CLIMB SLOWLY THROUGH THE END OF THE WEEK TO AROUND SEASONAL NORMALS BY THE COMING WEEKEND. PRELIMINARY POINT TEMPS/POPS... ABILENE 27 32 30 31 / 70 60 70 70 SAN ANGELO 31 37 32 40 / 60 60 70 70 JUNCTION 48 53 39 46 / 60 70 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR CALLAHAN-FISHER- JONES-NOLAN-SHACKELFORD-TAYLOR. WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON FOR CONCHO-IRION-MCCULLOCH-SAN SABA-TOM GREEN. WINTER STORM WATCH FROM MIDNIGHT CST TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-COKE-COLEMAN-RUNNELS-STERLING. ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR HASKELL-THROCKMORTON. && $$ 28/15 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 935 AM CST FRI JAN 12 2007 .UPDATE... WITH THE PROXIMITY OF THE COLD FRONT AND THE ONGOING PRECIPITATION HAVE ISSUED AN ICE STORM WARNING FOR HASKELL AND THROCKMORTON COUNTIES FROM 18Z TODAY THROUGH MONDAY. && .PREV DISCUSSION... /ISSUED 904 AM CST FRI JAN 12 2007/ UPDATE... DESPITE A LOT OF UNCERTAINTY HAVE EXTENDED WINTER STORM WATCH TO THE SOUTH TO INCLUDE STERLING...COKE...RUNNELS ...COLEMAN AND BROWN COUNTIES. THESE COUNTIES ARE ON THE BORDER OF WHERE THE FREEZING DRIZZLE AND FREEZING RAIN IS EXPECTED TO OCCUR. PREV DISCUSSION... /ISSUED 649 AM CST FRI JAN 12 2007/ AVIATION... A LOW-LEVEL JET WILL CONTINUE TO PRODUCE LOW-LEVEL WIND SHEAR ACROSS WEST CENTRAL TEXAS THIS MORNING. LOW CLOUDS WILL CONTINUE TO REDEVELOP AND MOVE INTO THE AREA THIS MORNING. CEILINGS WILL CONTINUE TO DROP INTO THE MVFR CATEGORY TODAY. A STRONG COLD FRONTAL BOUNDARY IS EXPECTED TO REACH THE ABILENE TERMINAL SHORTLY AFTER 00Z. IN ADDITION...EXPECT LIGHT RAIN TODAY. EXPECT FREEZING RAIN OR FREEZING DRIZZLE ACROSS THE BIG COUNTRY AFTER MIDNIGHT TONIGHT AS COLD ARCTIC AIR PUSHES SURFACE TEMPERATURES TO OR BELOW THE FREEZING MARK. FREEZING RAIN OR FREEZING DRIZZLE WILL THEN CONTINUE ACROSS THE BIG COUNTRY THROUGH 12Z TOMORROW MORNING. 23/HUBER PREV DISCUSSION... /ISSUED 435 AM CST FRI JAN 12 2007/ DISCUSSION... A COMPLICATED FORECAST WILL CONTINUE THROUGH THE WEEKEND AS THE ARCTIC FRONT CONTINUES TO CRASH THROUGH THE SOUTHERN PLAINS. LATEST SFC ANALYSIS SHOWS ARCTIC FRONT LOCATED FROM KTUL TO KOKC TO KCDS. EXPECT THE FRONT TO PUSH INTO THE BIG COUNTRY REACHING AN I-20 LINE BETWEEN 21Z AND 00Z. RUC/NAM SOLUTIONS SEEM TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT WITH THE GFS INITIALIZING SLIGHTLY WARMER WITH THE COLD AIR. GFS CONTINUES TO BE SLOWER WITH THE FRONTAL PUSH AS WELL. THE MAIN CHALLENGE CONTINUES TO BE HOW MUCH PROGRESS THE FRONT MAKES BEFORE STALLING AHEAD OF THE UPPER LEVEL TROUGH THAT IS EXPECTED TO PULL OUT OF THE SOUTHERN ROCKIES. BOTH 00Z AND 06Z NAM/GFS RUNS BRING THE FRONT INTO THE CONCHO VALLEY/HEARTLAND FRI NIGHT. THINK THE FRONT MAY STALL SOUTH OF A KSJT TO KBBD LINE BY SAT MORNING. FRONT WILL BE MAIN FORCING FOR PRECIPITATION DURING THE WEEKEND WITH STRONG ISENTROPIC LIFT OVER THE FRONTAL SURFACE THROUGH MUCH OF THE WEEKEND. SHOULD SEE CONTINUAL FREEZING DRIZZLE WHERE TEMPS NEAR THE SFC ARE COLD ENOUGH. OTHERWISE...FRONT SHOULD BE ON THE MOVE MORE ON SUNDAY AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE PLAINS. STRONG FRONTOGENETIC LIFT WILL BE POSSIBLE SUN NIGHT AS 850MB FRONT FINALLY PUSHES THROUGH THE REGION. WILL CARRY POPS THROUGH THIS TIME PERIOD. HIGH PRESSURE SHOULD CONTINUE TO BUILD INTO THE REGION MON AND TUE. WHILE PRECIP CHANCES LOOK GOOD THROUGH THE WEEKEND...OTHER FORECAST CHALLENGE WILL BE PRECIP TYPE. EXPECT ISOLATED THUNDERSTORMS AND SHOWERS AHEAD OF THE FRONT AND POSSIBLY LAST INTO THIS EVENING FOR THE BIG COUNTRY AS THERE MAY BE SOME ELEVATED INSTABILITY FOR CONVECTION. OTHERWISE THUNDERSTORM ACTIVITY WILL BE CONFINED TO WARM SECTOR SOUTH OF THE FRONT THROUGH THE WEEKEND. WILL LIKELY SEE FREEZING TEMPS WORK THEIR WAY INTO THE BIG COUNTRY MAINLY ALONG I-20 NORTHWARD TONIGHT INTO SAT MORNING. TEMPS MAY WARM A LITTLE TO ABOVE FREEZING ON SAT SO MAY SEE A MIX OF FREEZING RAIN AND RAIN DURING THE DAY. THREAT OF FREEZING RAIN WILL CONTINUE SAT NIGHT AS UPPER LEVEL TROUGH PULLS INTO THE PLAINS WITH SEVERAL DISTURBANCES IN THE JET. MAIN QUESTION WILL BE HOW FAR SOUTH FREEZING TEMPS WILL EXTEND. FOR NOW WILL KEEP FREEZING TEMPS CONFINED TO THE BIG COUNTRY AND KEEP MOST OF THE CONCHO VALLEY AND HEARTLAND NEAR OR ABOVE FREEZING WITH PRECIP TYPE BEING RAIN. TEMPS ON SUNDAY SHOULD DROP DURING THE DAY WITH PRECIP CHANCES DROPPING OFF INTO MONDAY. A WINTER STORM WATCH WILL CONTINUE FOR THE BIG COUNTRY BUT COULD BE UPGRADED. RIGHT NOW IT LOOKS LIKE ICE ACCUMULATIONS WILL REMAIN BELOW CRITERIA BUT THIS COULD CHANGE IF FREEZING TEMPS MOVE INTO THE AREA FASTER THAN EXPECTED. THIS MAY BE POSSIBLE CONSIDERING THE FRONTAL MOVEMENT BEING FASTER THAN WHAT THE MODELS HAVE BEEN SHOWING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 29 36 28 / 50 60 60 70 SAN ANGELO 67 50 51 38 / 50 50 60 70 JUNCTION 67 59 62 56 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-CALLAHAN-COKE-COLEMAN-FISHER-JONES-NOLAN-RUNNELS- SHACKELFORD-STERLING-TAYLOR. ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR HASKELL-THROCKMORTON. && $$ 28/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 904 AM CST FRI JAN 12 2007 .UPDATE... DESPITE A LOT OF UNCERTAINITY HAVE EXTENDED WINTER STORM WATCH TO THE SOUTH TO INCLUDE STERLING...COKE...RUNNELS ...COLEMAN AND BROWN COUNTIES. THESE COUNTIES ARE ON THE BORDER OF WHERE THE FREESING DRIZZLE AND FREEZING RAIN IS EXPECTED TO OCCUR. && .PREV DISCUSSION... /ISSUED 649 AM CST FRI JAN 12 2007/ AVIATION... A LOW-LEVEL JET WILL CONTINUE TO PRODUCE LOW-LEVEL WIND SHEAR ACROSS WEST CENTRAL TEXAS THIS MORNING. LOW CLOUDS WILL CONTINUE TO REDEVELOP AND MOVE INTO THE AREA THIS MORNING. CEILINGS WILL CONTINUE TO DROP INTO THE MVFR CATEGORY TODAY. A STRONG COLD FRONTAL BOUNDARY IS EXPECTED TO REACH THE ABILENE TERMINAL SHORTLY AFTER 00Z. IN ADDITION...EXPECT LIGHT RAIN TODAY. EXPECT FREEZING RAIN OR FREEZING DRIZZLE ACROSS THE BIG COUNTRY AFTER MIDNIGHT TONIGHT AS COLD ARCTIC AIR PUSHES SURFACE TEMPERATURES TO OR BELOW THE FREEZING MARK. FREEZING RAIN OR FREEZING DRIZZLE WILL THEN CONTINUE ACROSS THE BIG COUNTRY THROUGH 12Z TOMORROW MORNING. 23/HUBER PREV DISCUSSION... /ISSUED 435 AM CST FRI JAN 12 2007/ DISCUSSION... A COMPLICATED FORECAST WILL CONTINUE THROUGH THE WEEKEND AS THE ARCTIC FRONT CONTINUES TO CRASH THROUGH THE SOUTHERN PLAINS. LATEST SFC ANALYSIS SHOWS ARCTIC FRONT LOCATED FROM KTUL TO KOKC TO KCDS. EXPECT THE FRONT TO PUSH INTO THE BIG COUNTRY REACHING AN I-20 LINE BETWEEN 21Z AND 00Z. RUC/NAM SOLUTIONS SEEM TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT WITH THE GFS INITIALIZING SLIGHTLY WARMER WITH THE COLD AIR. GFS CONTINUES TO BE SLOWER WITH THE FRONTAL PUSH AS WELL. THE MAIN CHALLENGE CONTINUES TO BE HOW MUCH PROGRESS THE FRONT MAKES BEFORE STALLING AHEAD OF THE UPPER LEVEL TROUGH THAT IS EXPECTED TO PULL OUT OF THE SOUTHERN ROCKIES. BOTH 00Z AND 06Z NAM/GFS RUNS BRING THE FRONT INTO THE CONCHO VALLEY/HEARTLAND FRI NIGHT. THINK THE FRONT MAY STALL SOUTH OF A KSJT TO KBBD LINE BY SAT MORNING. FRONT WILL BE MAIN FORCING FOR PRECIPITATION DURING THE WEEKEND WITH STRONG ISENTROPIC LIFT OVER THE FRONTAL SURFACE THROUGH MUCH OF THE WEEKEND. SHOULD SEE CONTINUAL FREEZING DRIZZLE WHERE TEMPS NEAR THE SFC ARE COLD ENOUGH. OTHERWISE...FRONT SHOULD BE ON THE MOVE MORE ON SUNDAY AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE PLAINS. STRONG FRONTOGENETIC LIFT WILL BE POSSIBLE SUN NIGHT AS 850MB FRONT FINALLY PUSHES THROUGH THE REGION. WILL CARRY POPS THROUGH THIS TIME PERIOD. HIGH PRESSURE SHOULD CONTINUE TO BUILD INTO THE REGION MON AND TUE. WHILE PRECIP CHANCES LOOK GOOD THROUGH THE WEEKEND...OTHER FORECAST CHALLENGE WILL BE PRECIP TYPE. EXPECT ISOLATED THUNDERSTORMS AND SHOWERS AHEAD OF THE FRONT AND POSSIBLY LAST INTO THIS EVENING FOR THE BIG COUNTRY AS THERE MAY BE SOME ELEVATED INSTABILITY FOR CONVECTION. OTHERWISE THUNDERSTORM ACTIVITY WILL BE CONFINED TO WARM SECTOR SOUTH OF THE FRONT THROUGH THE WEEKEND. WILL LIKELY SEE FREEZING TEMPS WORK THEIR WAY INTO THE BIG COUNTRY MAINLY ALONG I-20 NORTHWARD TONIGHT INTO SAT MORNING. TEMPS MAY WARM A LITTLE TO ABOVE FREEZING ON SAT SO MAY SEE A MIX OF FREEZING RAIN AND RAIN DURING THE DAY. THREAT OF FREEZING RAIN WILL CONTINUE SAT NIGHT AS UPPER LEVEL TROUGH PULLS INTO THE PLAINS WITH SEVERAL DISTURBANCES IN THE JET. MAIN QUESTION WILL BE HOW FAR SOUTH FREEZING TEMPS WILL EXTEND. FOR NOW WILL KEEP FREEZING TEMPS CONFINED TO THE BIG COUNTRY AND KEEP MOST OF THE CONCHO VALLEY AND HEARTLAND NEAR OR ABOVE FREEZING WITH PRECIP TYPE BEING RAIN. TEMPS ON SUNDAY SHOULD DROP DURING THE DAY WITH PRECIP CHANCES DROPPING OFF INTO MONDAY. A WINTER STORM WATCH WILL CONTINUE FOR THE BIG COUNTRY BUT COULD BE UPGRADED. RIGHT NOW IT LOOKS LIKE ICE ACCUMULATIONS WILL REMAIN BELOW CRITERIA BUT THIS COULD CHANGE IF FREEZING TEMPS MOVE INTO THE AREA FASTER THAN EXPECTED. THIS MAY BE POSSIBLE CONSIDERING THE FRONTAL MOVEMENT BEING FASTER THAN WHAT THE MODELS HAVE BEEN SHOWING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 29 36 28 / 50 60 60 70 SAN ANGELO 67 50 51 38 / 50 50 60 70 JUNCTION 67 59 62 56 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-CALLAHAN-COKE-COLEMAN-FISHER-HASKELL-JONES-NOLAN- RUNNELS-SHACKELFORD-STERLING-TAYLOR-THROCKMORTON. && $$ 28/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 649 AM CST FRI JAN 12 2007 .AVIATION... A LOW-LEVEL JET WILL CONTINUE TO PRODUCE LOW-LEVEL WIND SHEAR ACROSS WEST CENTRAL TEXAS THIS MORNING. LOW CLOUDS WILL CONTINUE TO REDEVELOP AND MOVE INTO THE AREA THIS MORNING. CEILINGS WILL CONTINUE TO DROP INTO THE MVFR CATEGORY TODAY. A STRONG COLD FRONTAL BOUNDARY IS EXPECTED TO REACH THE ABILENE TERMINAL SHORTLY AFTER 00Z. IN ADDITION...EXPECT LIGHT RAIN TODAY. EXPECT FREEZING RAIN OR FREEZING DRIZZLE ACROSS THE BIG COUNTRY AFTER MIDNIGHT TONIGHT AS COLD ARCTIC AIR PUSHES SURFACE TEMPERATURES TO OR BELOW THE FREEZING MARK. FREEZING RAIN OR FREEZING DRIZZLE WILL THEN CONTINUE ACROSS THE BIG COUNTRY THROUGH 12Z TOMORROW MORNING. 23/HUBER && .PREV DISCUSSION... /ISSUED 435 AM CST FRI JAN 12 2007/ DISCUSSION... A COMPLICATED FORECAST WILL CONTINUE THROUGH THE WEEKEND AS THE ARCTIC FRONT CONTINUES TO CRASH THROUGH THE SOUTHERN PLAINS. LATEST SFC ANALYSIS SHOWS ARCTIC FRONT LOCATED FROM KTUL TO KOKC TO KCDS. EXPECT THE FRONT TO PUSH INTO THE BIG COUNTRY REACHING AN I-20 LINE BETWEEN 21Z AND 00Z. RUC/NAM SOLUTIONS SEEM TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT WITH THE GFS INITIALIZING SLIGHTLY WARMER WITH THE COLD AIR. GFS CONTINUES TO BE SLOWER WITH THE FRONTAL PUSH AS WELL. THE MAIN CHALLENGE CONTINUES TO BE HOW MUCH PROGRESS THE FRONT MAKES BEFORE STALLING AHEAD OF THE UPPER LEVEL TROUGH THAT IS EXPECTED TO PULL OUT OF THE SOUTHERN ROCKIES. BOTH 00Z AND 06Z NAM/GFS RUNS BRING THE FRONT INTO THE CONCHO VALLEY/HEARTLAND FRI NIGHT. THINK THE FRONT MAY STALL SOUTH OF A KSJT TO KBBD LINE BY SAT MORNING. FRONT WILL BE MAIN FORCING FOR PRECIPITATION DURING THE WEEKEND WITH STRONG ISENTROPIC LIFT OVER THE FRONTAL SURFACE THROUGH MUCH OF THE WEEKEND. SHOULD SEE CONTINUAL FREEZING DRIZZLE WHERE TEMPS NEAR THE SFC ARE COLD ENOUGH. OTHERWISE...FRONT SHOULD BE ON THE MOVE MORE ON SUNDAY AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE PLAINS. STRONG FRONTOGENETIC LIFT WILL BE POSSIBLE SUN NIGHT AS 850MB FRONT FINALLY PUSHES THROUGH THE REGION. WILL CARRY POPS THROUGH THIS TIME PERIOD. HIGH PRESSURE SHOULD CONTINUE TO BUILD INTO THE REGION MON AND TUE. WHILE PRECIP CHANCES LOOK GOOD THROUGH THE WEEKEND...OTHER FORECAST CHALLENGE WILL BE PRECIP TYPE. EXPECT ISOLATED THUNDERSTORMS AND SHOWERS AHEAD OF THE FRONT AND POSSIBLY LAST INTO THIS EVENING FOR THE BIG COUNTRY AS THERE MAY BE SOME ELEVATED INSTABILITY FOR CONVECTION. OTHERWISE THUNDERSTORM ACTIVITY WILL BE CONFINED TO WARM SECTOR SOUTH OF THE FRONT THROUGH THE WEEKEND. WILL LIKELY SEE FREEZING TEMPS WORK THEIR WAY INTO THE BIG COUNTRY MAINLY ALONG I-20 NORTHWARD TONIGHT INTO SAT MORNING. TEMPS MAY WARM A LITTLE TO ABOVE FREEZING ON SAT SO MAY SEE A MIX OF FREEZING RAIN AND RAIN DURING THE DAY. THREAT OF FREEZING RAIN WILL CONTINUE SAT NIGHT AS UPPER LEVEL TROUGH PULLS INTO THE PLAINS WITH SEVERAL DISTURBANCES IN THE JET. MAIN QUESTION WILL BE HOW FAR SOUTH FREEZING TEMPS WILL EXTEND. FOR NOW WILL KEEP FREEZING TEMPS CONFINED TO THE BIG COUNTRY AND KEEP MOST OF THE CONCHO VALLEY AND HEARTLAND NEAR OR ABOVE FREEZING WITH PRECIP TYPE BEING RAIN. TEMPS ON SUNDAY SHOULD DROP DURING THE DAY WITH PRECIP CHANCES DROPPING OFF INTO MONDAY. A WINTER STORM WATCH WILL CONTINUE FOR THE BIG COUNTRY BUT COULD BE UPGRADED. RIGHT NOW IT LOOKS LIKE ICE ACCUMULATIONS WILL REMAIN BELOW CRITERIA BUT THIS COULD CHANGE IF FREEZING TEMPS MOVE INTO THE AREA FASTER THAN EXPECTED. THIS MAY BE POSSIBLE CONSIDERING THE FRONTAL MOVEMENT BEING FASTER THAN WHAT THE MODELS HAVE BEEN SHOWING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 29 36 28 / 50 60 60 70 SAN ANGELO 67 50 51 38 / 50 50 60 70 JUNCTION 67 59 62 56 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR CALLAHAN-FISHER-HASKELL-JONES-NOLAN-SHACKELFORD-TAYLOR- THROCKMORTON. && $$ 23/HUBER tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 435 AM CST FRI JAN 12 2007 .DISCUSSION... A COMPLICATED FORECAST WILL CONTINUE THROUGH THE WEEKEND AS THE ARCTIC FRONT CONTINUES TO CRASH THROUGH THE SOUTHERN PLAINS. LATEST SFC ANALYSIS SHOWS ARCTIC FRONT LOCATED FROM KTUL TO KOKC TO KCDS. EXPECT THE FRONT TO PUSH INTO THE BIG COUNTRY REACHING AN I-20 LINE BETWEEN 21Z AND 00Z. RUC/NAM SOLUTIONS SEEM TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT WITH THE GFS INITIALIZING SLIGHTLY WARMER WITH THE COLD AIR. GFS CONTINUES TO BE SLOWER WITH THE FRONTAL PUSH AS WELL. THE MAIN CHALLENGE CONTINUES TO BE HOW MUCH PROGRESS THE FRONT MAKES BEFORE STALLING AHEAD OF THE UPPER LEVEL TROUGH THAT IS EXPECTED TO PULL OUT OF THE SOUTHERN ROCKIES. BOTH 00Z AND 06Z NAM/GFS RUNS BRING THE FRONT INTO THE CONCHO VALLEY/HEARTLAND FRI NIGHT. THINK THE FRONT MAY STALL SOUTH OF A KSJT TO KBBD LINE BY SAT MORNING. FRONT WILL BE MAIN FORCING FOR PRECIPITATION DURING THE WEEKEND WITH STRONG ISENTROPIC LIFT OVER THE FRONTAL SURFACE THROUGH MUCH OF THE WEEKEND. SHOULD SEE CONTINUAL FREEZING DRIZZLE WHERE TEMPS NEAR THE SFC ARE COLD ENOUGH. OTHERWISE...FRONT SHOULD BE ON THE MOVE MORE ON SUNDAY AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE PLAINS. STRONG FRONTOGENETIC LIFT WILL BE POSSIBLE SUN NIGHT AS 850MB FRONT FINALLY PUSHES THROUGH THE REGION. WILL CARRY POPS THROUGH THIS TIME PERIOD. HIGH PRESSURE SHOULD CONTINUE TO BUILD INTO THE REGION MON AND TUE. WHILE PRECIP CHANCES LOOK GOOD THROUGH THE WEEKEND...OTHER FORECAST CHALLENGE WILL BE PRECIP TYPE. EXPECT ISOLATED THUNDERSTORMS AND SHOWERS AHEAD OF THE FRONT AND POSSIBLY LAST INTO THIS EVENING FOR THE BIG COUNTRY AS THERE MAY BE SOME ELEVATED INSTABILITY FOR CONVECTION. OTHERWISE THUNDERSTORM ACTIVITY WILL BE CONFINED TO WARM SECTOR SOUTH OF THE FRONT THROUGH THE WEEKEND. WILL LIKELY SEE FREEZING TEMPS WORK THEIR WAY INTO THE BIG COUNTRY MAINLY ALONG I-20 NORTHWARD TONIGHT INTO SAT MORNING. TEMPS MAY WARM A LITTLE TO ABOVE FREEZING ON SAT SO MAY SEE A MIX OF FREEZING RAIN AND RAIN DURING THE DAY. THREAT OF FREEZING RAIN WILL CONTINUE SAT NIGHT AS UPPER LEVEL TROUGH PULLS INTO THE PLAINS WITH SEVERAL DISTURBANCES IN THE JET. MAIN QUESTION WILL BE HOW FAR SOUTH FREEZING TEMPS WILL EXTEND. FOR NOW WILL KEEP FREEZING TEMPS CONFINED TO THE BIG COUNTRY AND KEEP MOST OF THE CONCHO VALLEY AND HEARTLAND NEAR OR ABOVE FREEZING WITH PRECIP TYPE BEING RAIN. TEMPS ON SUNDAY SHOULD DROP DURING THE DAY WITH PRECIP CHANCES DROPPING OFF INTO MONDAY. A WINTER STORM WATCH WILL CONTINUE FOR THE BIG COUNTRY BUT COULD BE UPGRADED. RIGHT NOW IT LOOKS LIKE ICE ACCUMULATIONS WILL REMAIN BELOW CRITERIA BUT THIS COULD CHANGE IF FREEZING TEMPS MOVE INTO THE AREA FASTER THAN EXPECTED. THIS MAY BE POSSIBLE CONSIDERING THE FRONTAL MOVEMENT BEING FASTER THAN WHAT THE MODELS HAVE BEEN SHOWING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 29 36 28 / 50 60 60 70 SAN ANGELO 67 50 51 38 / 50 50 60 70 JUNCTION 67 59 62 56 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR CALLAHAN-FISHER-HASKELL-JONES-NOLAN-SHACKELFORD-TAYLOR- THROCKMORTON. && $$ 10 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 1153 PM CST WED JAN 10 2007 .AVIATION... MAIN PROBLEM CONCERNS THE DEVELOPMENT OF THE LOW CLOUD DECK. THE MODEL GUIDANCE LINED UP WITH THE CURRENT OBSERVATIONS FAIRLY WELL...MOS GUIDANCE WAS OKAY ON A SCALE OF NOT GOOD...OKAY...AND GOOD. LIKED HOW THE RUC...NAM12...AND GFS ALL LINED UP THE BEST LOW-LEVEL MOISTURE OVER THE EASTERN AND WESTERN COUNTIES EARLY... THEN FILLED IN THE CENTRAL AREAS LATER TONIGHT. THUS...EXPECT MVFR CEILINGS TO DEVELOP BETWEEN 08Z AND 10Z OVER MOST OF THE SITES FROM HOU NORTH TO UTS AND WEST TO CLL. SGR AND LBX MAY LAG AN HOUR TO 11Z AND GLS TO 14Z. THE CONFIDENCE LEVEL IS GOOD OVER THE INLAND SITES NORTH OF INTERSTATE 10 AND THE TWO BIG AIRPORTS IN HOUSTON. THURSDAY LOOKS TO BE A DIFFICULT DAY. THE MODEL GUIDANCE WAS SUGGESTING SOME BRIEF VFR BREAKS DURING THE AFTERNOON AS THE SURFACE WINDS PICK UP. THE MAV GUIDANCE LOOKS REASONABLE IN BRINGING IN SEA FOG AT GLS DURING THE EVENING. && .PREV DISCUSSION... /ISSUED 827 PM CST WED JAN 10 2007/ UPDATE... CLOUDS INCREASING A BIT FASTER THAN PROGGED. SATELLITE DERIVED PW SHOWS MOISTURE INCREASING FROM THE GULF AND THIS SHOWS UP WELL IN THE 11-3.9 SATELLITE IMAGERY. THINK MIN TEMP FORECAST IS OK...BUT WILL WATCH CLOUD TRENDS AND IF AN OVERCAST DEVELOPS...WILL LIKELY RAISE MIN TEMPS A FEW DEGREES. WILL UPDATE ZONES TO TWEAK SKY COVER OTHERWISE NO CHANGES. && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 66 52 67 62 73 / 0 0 10 20 40 HOUSTON (IAH) 66 51 69 61 73 / 0 0 10 10 20 GALVESTON (GLS) 63 57 69 62 71 / 0 0 10 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...43 AVIATION/MARINE...40 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1035 PM CST WED JAN 10 2007 .AVIATION... NO MAJOR CHANGES TO PREVIOUS THINKING. STRATUS HAS BEEN SLOWER TO DEVELOP THAN PREVIOUSLY FORECAST. CURRENT THINKING HAS MVFR CIGS DEVELOPING BY 08Z FOR ACT AND 09Z FOR THE METROPLEX SITES. CIGS MAY DROP AS LOW AS IFR TOMORROW MORNING...AND WILL CONTINUE TO REMAIN IN THE MVFR CATEGORY THRU THE DAY. RAIN CHANCES STILL LOOK BEST BEYOND THIS TAF CYCLE. /13 && .UPDATE... 935 PM CST WED JAN 10 2007 MINOR UPDATES TO TRENDS TONIGHT AND TO RAISE LOWS IN URBAN AREAS... AND LOWER THEM IN THE EAST A FEW DEGREES...AS LOW CLOUD COVER PER RUC/NAM LOOK TO BE IN LINE WITH MOST STRATUS SLOW TO FORM THROUGH 06Z...BUT SHOULD SURGE QUICKLY AFTERWARDS. THUS WE`LL CONTINUE TO SEE TEMPS SLOWLY DROP ACROSS MOST AREAS...THEN REMAIN STEADY OR EVEN RISE SLIGHTLY TOWARD MORNING WITH THE STRATUS AND STRONG S/SELY WNDS. ALSO ADJUSTED MSTR/RH/DEW PTS. UPDATES OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 505 PM CST WED JAN 10 2007/ AVIATION... MAIN CHALLENGE FOR THE TAFS WILL BE THE LOW CLOUDS WHICH WILL START TO DEVELOP OVERNIGHT. 40-45 KT LOW LEVEL JET WILL HELP ATMOSPHERE QUICKLY SATURATE. EXPECT MVFR CIGS TO BE PREDOMINANT...ALTHOUGH IFR CIGS WILL BE POSSIBLE. CIGS WILL NOT IMPROVE MUCH WITH DAYBREAK AND AGAIN EXPECT OVC MVFR THRU THE DAY. SOUTHERLY WINDS WILL CONTINUE... WITH SPEEDS DROPPING OFF ONLY SLIGHTLY THIS EVENING AND INCREASING AGAIN BY TOMORROW AFTERNOON. BEST RAIN CHANCES LOOK TO BE BEYOND THIS TAF SET. /13 DISCUSSION... 323 PM CST WED JAN 10 2007 SOUTH WINDS HAVE QUICKLY RETURNED TO THE AREA WITH A LARGE REGION OF 4-6 MB 3 HOUR PRESSURE FALLS ACROSS THE ENTIRE CENTRAL PART OF THE COUNTRY. THESE WINDS WILL USHER IN GULF MOISTURE IN THE OVERNIGHT HOURS...ALLOWING FOR RAPID SATURATION OF THE LOW LEVELS. CLOUDY SKIES WILL PREVAIL BY SUNRISE AS LOW CLOUDS MOVE IN FROM THE SOUTH AND HIGH AND MID LEVEL PACIFIC MOISTURE STREAMS IN FROM THE SOUTHWEST. MOISTURE BECOMES DEEP ENOUGH FOR STREAMER SHOWERS WITHIN WARM ADVECTION ZONE OF THE LOW LEVEL JET BY THURSDAY NIGHT. BETTER CHANCES OF RAIN WILL BEGIN ON FRIDAY AS CAP ERODES AND MOIST/UNSTABLE ENVIRONMENT IS IN PLACE. SUBTLE LIFTING IS EVIDENT ON THE COMPUTER MODELS...BUT UPPER TROUGH WILL BE FAIRLY FAR AWAY AND WENT WITH THE DRIER NAM SOLUTION FRIDAY. STILL DO EXPECT SCATTERED CONVECTION...BUT WILL NOT BUY INTO THE LIKELY POPS ADVERTISED BY THE MAV MOS UNTIL LATE FRIDAY NIGHT. MEANWHILE...ARCTIC AIRMASS IS NOW BEGINNING TO NOSE INTO MONTANA BEHIND POWERFUL SURFACE LOW IN SOUTH DAKOTA. 1050 MB ARCTIC HIGH WILL BUILD SOUTH INTO THE NORTHERN PLAINS BY FRIDAY MORNING WITH SINGLE DIGIT TEMPERATURES AS FAR SOUTH AS NEBRASKA. UPPER LEVEL TROUGH WILL ALSO DIG SOUTH ACROSS THE WEST COAST WHICH IS THE PRIMARY CULPRIT FOR FRONTAL TIMING UNCERTAINTIES AND FREEZING RAIN CHANCES OVER THE NW CWA. SOUTHWEST FLOW AROUND THE UPPER TROUGH WILL TRY TO HOLD THE FRONT BACK...BUT THIS AIRMASS WILL BE EXTRAORDINARILY DENSE...AND A SHALLOW 50-100 MB DEEP LAYER OF ARCTIC AIR WILL SPILL SOUTHWARD INTO OKLAHOMA BY FRIDAY. A GOOD ANALOGY TO THIS PROCESS WOULD BE LIKE POURING WATER ON A TABLE WITH THE WATER SPREADING OUTWARDS. THE NAM MODEL TYPICALLY DOES A BETTER JOB WITH SHALLOW ARCTIC AIRMASSES...AND HAS THE FRONT MOVING THOUGH FASTER/STRONGER THAN THE OTHER MODELS. SEE NO REASON NOT TO FOLLOW THE NAM FORECAST CLOSELY GIVEN ITS TRACK RECORD. WE EXPECT THE FRONT TO REACH THE NW CWA FRIDAY EVENING AND GRADUALLY MARCH SOUTH SATURDAY. WE HAVE THE FRONT CROSSING THE METROPLEX AT 9 AM SATURDAY...WACO AT 7 PM...AND FINALLY CLEARING THE SE ZONES BY 3 AM SUNDAY. POST FRONTAL RAIN/FOG/DRIZZLE WILL BE FAIRLY WIDESPREAD AS ISENTROPIC LIFT ENSUES WITH 40-50 KT SOUTHERLY LOW LEVEL FLOW ABOVE THE FRONT REMAINING INTACT. FREEZING TEMPS ARE EXPECTED TO MOVE INTO THE NW CWA BY SATURDAY EVENING AND REACH A PARIS TO DALLAS TO COMANCHE LINE BY SUNDAY MORNING. ANY LINGERING PRECIP WOULD FALL AS FREEZING RAIN. IT IS STILL TOO EARLY TO ANTICIPATE POSSIBLE ACCUMULATION OR IMPACTS...AND ANY SLIGHT DEVIATION IN THE FORECAST TEMPS WOULD GREATLY AFFECT THE ICE POTENTIAL. THE PRECIPITATION SHOULD FINALLY EXIT FROM WEST TO EAST DURING THE DAY SUNDAY WITH GENERALLY PARTLY CLOUDY AND DRY CONDITIONS EXPECTED INTO THE MIDDLE OF NEXT WEEK. IT WILL BE COLD...AND STAY RATHER CHILLY THROUGH WEDNESDAY. TEMPERATURES AROUND 20 FOR LOWS AND THE MIDDLE TO UPPER 30S FOR HIGHS APPEAR REASONABLE GIVEN THE SLOWLY MODIFYING LOW LEVEL THICKNESSES. WENT JUST A LITTLE COLDER THAN 12Z MEX MOS FOR LOWS...BUT 5-10 DEGREES COLDER FOR THE HIGHS. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 51 65 60 68 55 / 10 10 30 40 80 WACO, TX 53 66 61 70 62 / 10 10 30 40 40 PARIS, TX 45 59 58 66 57 / 10 10 30 40 80 DENTON, TX 50 64 58 67 48 / 10 10 30 40 80 MCKINNEY, TX 50 63 59 67 53 / 10 10 30 40 80 DALLAS, TX 52 65 61 69 58 / 10 10 30 40 80 TERRELL, TX 49 63 60 69 60 / 10 10 30 40 80 CORSICANA, TX 51 64 62 70 62 / 10 10 30 40 60 TEMPLE, TX 52 66 62 71 62 / 10 10 30 40 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/13/92 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 917 PM CST THU JAN 11 2007 .UPDATE...SOME LIGHT RAIN AND DRIZZLE HAS AFFECTED SOUTHWEST CORNER OF WI AND SMALL PART OF ADJACENT NORTHEAST IOWA ZONES THIS EVENING. THIS WAS ASSOCIATED WITH WAVE ADVANCING ALONG SURFACE FRONT...WHICH WAS STILL LITERALLY CRAWLING ACROSS SOUTHWEST CORNER OF WI. IN ADDITION...AREAS OF FOG DEVELOPED IN MOIST BOUNDARY LAYER WITH LIGHT WINDS IN THIS AREA. LATEST RUC INDICATED FORCING ASSOCIATED WITH ISENTROPIC LIFT ON THE 290K SURFACE...AS WELL AS Q-G CONVERGENCE...WAS ON THE WANE. THIS WAS CORROBORATED BY DECREASE IN PRECIPITATION OVER AFOREMENTIONED PART OF THE FORECAST AREA. DATA BASE HAS BEEN UPDATED TO INCORPORATE LATEST PRECIPITATION TRENDS...WHICH WILL HAVE DRIZZLE AND FOG ENDING BETWEEN 03Z-06Z THIS EVENING ACROSS SOUTHERN MOST SECTIONS OF THE FORECAST AREA. PLAN TO UPDATE ZONES BY 0330Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ THOMPSON wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1107 AM CST THU JAN 11 2007 .UPDATE... LATEST 16Z SURFACE ANALYSIS INDICATES SURFACE COLD FRONT EXTENDING FROM NORTHWEST WISCONSIN INTO NORTHEAST IOWA. TEMPERATURES OUT AHEAD OF FRONT WELL INTO THE UPPER 30S TO MIDDLE 40S. BEHIND THE FRONT TEMPERATURES IN THE MIDDLE TO UPPER 20S. LATEST 15Z RUC INDICATES SURFACE COLD FRONT TO CONTINUE TO MOVE ACROSS THE FORECAST AREA THIS AFTERNOON. 15Z RUC INDICATES SURFACE LOW OVER NORTHEAST KANSAS WILL MOVE NORTHEAST ALONG FRONT AND INTO SOUTHERN IOWA BY 00Z FRIDAY. BOTH THE 12Z NAM AND 15Z RUC CONTINUE TO INDICATE GOOD LOW LEVEL MOISTURE AND WEAK VERTICAL MOTION UP TO 750MB BY 21Z ACROSS SOUTHERN FORECAST AREA...AND WEAK ISENTROPIC LIFT AT 290K SURFACE. BOTH THE 12Z NAM AND 15Z RUC FORECAST SOUNDINGS INDICATE NO INTRODUCTION OF ICE INTO LOW LEVELS COMBINED WITH TEMPERATURES ABOVE FREEZING ALOFT AND AT SURFACE ACROSS SOUTHERN FORECAST AREA. PRECIPITATION WILL REMAIN ALL RAIN ACROSS SOUTHERN FORECAST AREA. WILL CONTINUE WITH PREVIOUS FORECAST THIS AFTERNOON AND UPDATE FOR MORNING WORDING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ DTJ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 105 AM EST SAT JAN 13 2007 .AVIATION... COLD FRONT HAD MOVED SOUTH OF FWA BY 06Z...WITH MUCH COLDER AIR SPREADING IN FROM THE NORTH. PRECIPITATION SHOULD BE ENDING VERY CLOSE TO THE TIME IT WILL BE COLD ENOUGH FOR SLEET AT SBN...SO HAVE INCLUDED A BRIEF MENTION OF SLEET AT SBN. NEXT ROUND OF PRECIPITATION TONIGHT SHOULD STILL BE A CLOSE CALL BETWEEN LIQUID...FREEZING AND FROZEN...BUT FOR NOW WENT WITH LIGHT FREEZING RAIN/SLEET AT SBN AND JUST RAIN AT FWA. CIGS SHOULD BE MAINLY IFR THROUGH THE TAF PERIOD. && .UPDATE... AT 02Z...A COLD FRONT WAS LOCATED FROM SRN ONTARIO...FAR SE MICHIGAN...THEN IT EXTENDED SW INTO NE...CNTRL...AND SW INDIANA. THE FRONT WILL CONTINUE TO SAG THROUGH THE REMAINDER OF THE FCST AREA OVERNIGHT. UPR LVL DIVERGENCE IN ASSOCIATION WITH WEAK WX DISTURBANCES AND UPR LVL JET DYNAMICS WILL TEAM UP WITH ISENTROPIC LIFT/OVERRUNNING OVER THE AFOREMENTIONED FRONTAL BOUNDARY TONIGHT. HENCE...PCPN WILL BE WIDESPREAD FOR MOST OF THE REGION. LATEST RUC SOUNDINGS SUGGEST THAT SOME SLEET MAY MIX IN ACRS THE NRN AND NWRN CWFA LATE TONIGHT AS COLDER AIR IN THE LOW LVLS SLOWLY FILTERS SOUTHEAST. HAVE MADE SOME MINOR ADJUSTMENTS TO THE ZONES/GRIDS. BELIEVE CHC/S FOR SNOW ARE SLIM TONIGHT BASED ON LATEST MODEL SOUNDINGS...SO HAVE REMOVED SNOW AND HAVE GONE WITH JUST A CHC OF SLEET. HAVE ALSO MODIFIED OVERNIGHT LOWS A TAD...WHICH WILL RANGE FROM THE LOWER 30S N AND NW TO THE UPPER 30S SOUTHEAST. TEMPERATURES WILL FALL TO AROUND 32 DEGREES IN THE N AND NW BY SATURDAY MORNING. HAVE OPTED TO LEAVE OUT FREEZING RAIN CHC/S DUE TO THE BORDERLINE VALUE. THERE COULD BE A CHC OF FREEZING RAIN EARLY ON SATURDAY IF TEMPS DIP TO 31 DEGREES BRIEFLY. MIDNIGHT SHIFT SHOULD HAVE A BETTER HANDLE ON THIS POSSIBILITY AS THEY WATCH HOW FAR TEMPERATURES DROP OVERNIGHT. && .PREV DISCUSSION... SHORT TERM... BETWEEN TONIGHT AND TOMORROW THE BEST CHANCE FOR PRECIPITATION IS TONIGHT. THE SURFACE TROUGH IS IN THE AREA THROUGH TONIGHT AND WILL BE PULLING AWAY SOME FROM THE CWA TOMORROW. EVEN TOMORROW THE MORNING HOURS HAVE A BETTER CHANCE THAN THE AFTERNOON HOURS DO. WITH THE TROUGH SLIDING THROUGH THE SOUTHEASTERN HALF OF THE CWA THIS EVENING AND JUST TO OUR EAST AND SOUTHEAST TONIGHT...THIS WILL GIVE THE SOUTHERN PART OF THE CWA A BETTER CHANCE FOR PRECIP THAN THE NORTHERN PART. ALSO THIS WILL CAUSE TEMPERATURE PROFILES TO BE COLDER IN THE NORTHERN PART THAN IN THE SOUTHERN PART AND MORE SO NEAR THE SURFACE. THEREFORE AS TONIGHT WEARS ON FROM NORTH TO SOUTH...A MIX OF PRECIP HAS A CHANCE TO FORM. A LITTLE TRICKY TO SEE IF SURFACE TEMPERATURES ARE GOING TO GET COLD ENOUGH TONIGHT FOR FREEZING RAIN TO COME INTO THE MIX IN OUR NORTHERN COUNTIES...BUT DID NOT LOOK LIKE A BIG ENOUGH CHANCE TO MENTION IN THE FORECAST. IF SURFACE TEMPERATURES START DROPPING OFF MORE THAN EXPECTED AND THE SURFACE TROUGH MOVES FURTHER EAST AND SOUTH THAN EXPECTED...THEN SOME LIGHT FREEZING RAIN IS POSSIBLE FOR LATE TONIGHT INTO TOMORROW FOR OUR NORTHERN PART. BUT THERE IS SOME UNCERTAINTY IN HOW MUCH COLD AIR IS GOING TO PENETRATE INTO THE NORTHERN HALF OF THE CWA. ANY FREEZING OR FROZEN TYPE PRECIP TO FALL TONIGHT OR TOMORROW IS NOT EXPECTED TO AMOUNT TO AS MUCH AS THE SYSTEM NEXT WEEK IS LOOKING. LEFT TEMPERATURES ALONE FOR THE MOST PART EXCEPT TO DROP THE NORTH BY A DEGREE FOR TOMORROW. LONG TERM... CDFNT DROPPING SE INTO THE AREA THIS AFTN WILL STALL OVER THE OH RVR VALLEY ON SAT. DEEP TROF OVER WRN U.S. WILL CONT WSW-SW FLOW ALOFT OVER OUR AREA. WK DISTURBANCES MOVG NE AHEAD OF THE MAIN TROF WILL RESULT IN ONCL BACKING OF WINDS ALOFT AND ENHANCED OVER-RUNNING POTENTIAL. TIMING OF THESE WK SHRTWV`S IS HARD TO PIN DOWN AT THIS JUNCTURE AS MODELS NOT SURPRISINGLY ARE IN CONSIDERABLE DISAGREEMENT ON A COUPLE OF SUCH WAVES SAT NGT AND SUND. THUS, LEFT POPS FOR SAT NGT IN CHC CATEGORY FOR NOW AND CONTD WITH LOW QPF. OVERLAYING MSP SOUNDING WITH MODEL SOUNDINGS INDICATES ALL MODELS INITIALIZED THE ARCTIC AIRMASS TOO WARM BELOW 950MB AND NOT QUITE WARM ENOUGH WITH THE WARM LAYER ALOFT AROUND 700MB. THUS, HEDGED TOWARD A LITTLE WARMER AIR ALOFT AND COLDER AIR NEAR THE SFC FOR PTYPE AND MIN/MAX CONSIDERATIONS THIS WEEKEND. SGFNT PRECIP FROM THIS SCENARIO IS EXPECTED SUN AFTN-EVE AS STRONG TROF LIFTS ENE ACROSS CENTRAL PLAINS ENHANCING OVER-RUNNING OF SFC BOUNDARY. LEANED TOWARD GFS TIMING WHICH IS FASTER THAN NAM. STILL A GOOD POTENTIAL FOR FREEZING RAIN IN OUR AREA WITH THIS PATTERN. HELD OFF ON WATCH FOR NOW SINCE SGFNT PRECIP EXPECTED TO BEGIN LATE IN 4TH PD AT THE EARLIEST. HWVR, THERE IS POTENTIAL THAT WEAKER SHRTWV`S MOVG THROUGH THE AREA COULD NECESSITATE AN ADVISORY SOONER. NAM/GFS CONSISTENT INDICATING DRY SLOT WILL PUNCH INTO THE AREA LATE SUNDAY NGT BRINGING SGFNT PRECIP TO AN END WITH DEFORMATION ZONE PRECIP STAYING TO THE NORTH OF THE CWA. NORMALLY THIS IS NOT A SCENARIO FAVORABLE FOR HEAVY SNOW, BUT WITH VERY MOIST AMS (700MB MIXING RATIO AROUND 4G/KG SUN EVE) OVER-RUNNING THE ARCTIC BOUNDARY, CAN`T RULE THIS OUT. SOME LINGERING LIGHT SNOW PSBL MONDAY AS UPPER TROF SHEARS OUT ACROSS THE GRTLKS. GOING CHC OF LAKE EFFECT SNOW SHOWERS CONTINUES FOR MON NGT-TUE NGT AS INSTABILITY EXPECTED TO BECOME EXTREME, HWVR, INVERSION HEIGHTS AT THIS POINT LOOK RATHER LOW FOR SGFNT LAKE EFFECT SNOW. RIDGE EXPECTED TO MOVE ACROSS THE AREA WED WITH ANOTHER FRONT APPROACHING ON THU. THIS SHOULD BE A DRY PD BUT WITH PASSAGE OF THE CDFNT WILL BRING A RENEWED CHC OF LAKE EFFECT SNOW SHOWERS ALONG WITH COLDER TEMPS AGAIN FRI. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 3 PM EST FOR LMZ043-LMZ046. && $$ UPDATE...HICKMAN AVIATION...SKIPPER SHORT TERM...98 LONG TERM....01 in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 331 AM CST SAT JAN 13 2007 .DISCUSSION... THE MAIN CONCERN FOR TODAY THROUGH SUNDAY WILL BE PRECIPITATION TYPE AND HOW MUCH SNOW OR ICE WILL BE POSSIBLE DURING THE NEXT COUPLE OF DAYS. TODAY: LATEST IR LOOP AND SURFACE ANALYSIS SHOWING A FAIRLY STRONG WAVE MOVING THROUGH THE TEXAS PANHANDLE WITH EVEN SOME LIGHTNING STRIKES ASSOCIATED WITH IT. THIS WAVE WILL CONTINUE TO LIFT NORTHEAST THIS MORNING AND INCREASE THE ISENTROPIC ASCENT MARKEDLY ACROSS THE FORECAST AREA TODAY. THE 00Z GFS/RUC SEEM TO HANDLE THE STRENGTH OF THIS WAVE BASED ON THE IR AND WATER VAPOR LOOPS. AS A RESULT...WE ARE FAVORING THESE SOLUTIONS FOR THE POTENTIAL FOR SOME DECENT SNOW AND SLEET ACCUMULATIONS TODAY. WE ARE MAKING SOME ADJUSTMENTS TO THE PRECIPITATION TYPE OVER THE ENTIRE AREA SINCE IT APPEARS LIKE MOST OF BOUNDARY LAYER TEMPERATURES AROUND -10 DEG C WHICH IS SUPPORTIVE OF PRECIPITATION REFREEZING BEFORE IT REACHES THE GROUND. THEREFORE...WE ARE LOOKING AT MORE OF A SNOW OR SLEET POTENTIAL ACROSS SOUTHEAST KANSAS TODAY. THE MAIN CONCERN RIGHT NOW...IS SOUTH CENTRAL KANSAS WHERE THEY COULD SEE MORE IN THE WAY OF SNOW WITH ACCUMULATIONS UP TO 4 INCHES BY LATE AFTERNOON. THE GFS DOES SHOW SOME COOLING AROUND 700MB DUE TO LATENT HEAT PROCESS...BUT WE BELIEVE IT MAY NOT BE COOLING THAT COLUMN ENOUGH DUE TO SUCH STRONG LIFT IN THAT REGION. THE COBB TECHNIQUE IS ALSO SUPPORTIVE OF THIS. MEANWHILE...FOLKS IN CENTRAL KANSAS COULD SEE AT LEAST 2 INCHES OF SNOW. WE WENT AHEAD AND UPGRADED THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING AND CONTINUED IT THROUGH SUNDAY SINCE WE ARE ANTICIPATING THIS WHOLE EVENT TO PRODUCE 6 INCHES OF SNOW OR MORE OVER MOST OF CENTRAL AND SOUTH CENTRAL KANSAS. THE WINTER STORM WARNING STILL LOOKS GOOD FOR THE REMAINDER OF THE AREA SINCE THE SLEET AND SNOW ACCUMULATIONS WILL BE SIGNIFICANT. TONIGHT-SUNDAY: THE MODELS ARE ADVERTISING ANOTHER BREAK IN THE PRECIPITATION THIS EVENING...BEFORE THE MAIN UPPER TROF MOVES INTO THE WESTERN SECTIONS OF OUR FORECAST AREA OVERNIGHT. THIS TROF SHOULD BRING ANOTHER ROUND OF SNOW AND SLEET TO THE AREA WITH THE BEST CHANCE OF SNOW ACROSS CENTRAL AND SOUTH CENTRAL KANSAS WHERE ANOTHER 2 TO 5 INCHES OF SNOW WILL BE POSSIBLE BY SUNDAY EVENING WITH THE HIGHEST AMOUNTS EXPECTED TO BE IN CENTRAL KANSAS WHERE THEY WILL BE CLOSEST TO THE MID LEVEL BAROCLINIC ZONE. THERE WILL ALSO BE SOME AID FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET WHICH WILL INCREASE THE ISENTROPIC ASCENT WITH ADDITIONAL LIFT FROM MID LEVEL FRONTOGENETICAL CIRCULATIONS. WE MAY END UP INCREASING SNOW AMOUNTS EVEN MORE IN LATER FORECASTS. SUNDAY NIGHT-WEDNESDAY: WE SHOULD BEGIN TO SEE THE SNOW MOVING OUT OF THE PICTURE SUNDAY NIGHT. THEN THE ARCTIC HIGH WILL BEGIN TO SETTLE OVER US DURING THE NEXT COUPLE OF DAYS. WE LOWERED HIGHS AND LOWS SEVERAL DEGREES ESPECIALLY ON MONDAY AND TUESDAY WHERE THE SURFACE RIDGE BEGINS TO PARK OVER THE AREA. WITH LOTS OF SNOW COVER AND NORTHERLY FLOW OVER US...WE WILL BE HARD PRESSED TO MAKE INTO THE 20S WITH LOWS POSSIBLY DROPPING BELOW ZERO. COX && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 20 15 19 10 / 100 70 100 40 HUTCHINSON 18 14 17 8 / 100 70 100 40 NEWTON 19 14 18 9 / 100 80 100 40 ELDORADO 20 14 18 10 / 100 90 100 40 WINFIELD-KWLD 20 15 19 12 / 100 80 100 30 RUSSELL 15 10 14 5 / 100 70 100 50 GREAT BEND 17 12 16 6 / 100 80 100 50 SALINA 18 14 17 7 / 100 80 100 50 MCPHERSON 18 14 17 7 / 100 70 100 40 COFFEYVILLE 22 19 23 16 / 100 100 100 30 CHANUTE 21 17 21 14 / 100 100 100 40 IOLA 21 17 21 13 / 100 100 100 40 PARSONS-KPPF 21 19 22 15 / 100 100 100 30 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM CST SUNDAY FOR KSZ032-033- 047>053-067>072-082-083-091>096-098>100. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1110 PM CST FRI JAN 12 2007 .AVIATION... SCATTERED AREAS OF PCPN WILL CONTINUE ACROSS WEST CENTRAL TEXAS TONIGHT. THE PCPN WILL REMAIN FZRA ACROSS THE BIG COUNTRY. THE ARCTIC COLD FRONT IS LOCATED JUST NORTH OF THE I-10 CORRIDOR. PCPN WILL BECOME MORE WIDESPREAD ON SATURDAY AS A STRONG UPPER LEVEL SYSTEM MOVES ACROSS THE ARCTIC AIRMASS OVER NORTHERN AND CENTRAL TEXAS. THE PCPN TYPE WILL REMAIN FZRA ACROSS THE BIG COUNTRY THROUGH SATURDAY...WITH POSSIBLE FZRA ALONG A KBWD TO KSJT TO MERTZON LINE ON SATURDAY. IFR CIGS OF BLO OVC010 ARE EXPECTED ACROSS WEST CENTRAL TEXAS THROUGH 14/06Z. 21 && .PREV DISCUSSION... /ISSUED 1105 PM CST FRI JAN 12 2007/ UPDATE...UPDATED ONCE MORE TO ACCOUNT FOR CURRENT TEMPERATURE TRENDS WHICH WERE SLIGHTLY COOLER BEHIND THE FRONT THAN FORECAST. EXTRAPOLATED TRENDS OUT THROUGH TOMORROW MORNING AND PUSHED THE FRONT A LITTLE FURTHER TO THE SOUTH OF I-10. WHILE MUCH OF THE WIDESPREAD RAIN HAS ENDED FOR THE TIME BEING...KSJT RADAR INDICATES ISENTROPIC LIFT IS INCREASING AND ECHOES ARE ONCE AGAIN BEGINNING TO INCREASE. EXPECT THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE OVERNIGHT AS NEXT DISTURBANCE IS CURRENTLY MOVING INTO THE BIG BEND REGION. PERIODIC DISTURBANCES WILL CONTINUE TO MOVE ACROSS THE REGION. FREEZING LINE PER MESONET DATA FROM ROBERT LEE TO NEAR BROWNWOOD. WHERE THE LIGHT FREEZING RAIN IS NOT OCCURRING NORTH OF THIS LINE...AREAS OF FOG AND FREEZING DRIZZLE WILL CONTINUE TO PRODUCE LIGHT ICE ACCUMULATIONS UNTIL MORE SUBSTANTIAL PRECIPITATION STARTS LATER. BRAZZELL PREV DISCUSSION... /ISSUED 913 PM CST FRI JAN 12 2007/ UPDATE... UPDATE IS MAINLY FOR EXTENDING THE ICE STORM WARNING ONE SET OF COUNTIES FURTHER SOUTH WHICH INCLUDES THE NORTHERN CONCHO VALLEY AND NORTHERN HEARTLAND. ARCTIC COLD FRONT IS NOW LOCATED SOUTH OF A KBWD TO KSJT LINE...AND TEMPERATURES HAVE FALLEN INTO THE MID TO UPPER 20S ACROSS THE BIG COUNTRY. STRONG SUB TROPICAL JET WITH DISTURBANCES MOVING NORTHEAST SHOULD KEEP SCATTERED AREAS OF PCPN GOING THROUGH TONIGHT. LATEST MODEL RUN INDICATING MAIN UPPER LEVEL TROF LIFTING NORTHEAST ACROSS AREA SATURDAY NIGHT AND SUNDAY...LEADING TO NEXT ROUND OF FZRA AND POSSIBLE SIGNIFICANT ICE ACCUMULATIONS ACROSS THE NORTHERN HALF OF WEST CENTRAL TEXAS. PREV DISCUSSION... /ISSUED 557 PM CST FRI JAN 12 2007/ UPDATE...UPDATE ALREADY ISSUED TO ACCOUNT FOR TEMEPRATURE TRENDS ALREADY COOLER THAN GRIDS. FREEZING LINE NOW APPROACHING KABI WITH SOME TROUBLE SPOTS ACROSS HASKELL AND THROCKMORTON COUNTIES ALREADY OCCURING. ANTICIPATE THAT WE MAY HAVE TO PUSH THE WARNING ONE MORE ROW OF COUNTIES TO THE SOUTH THIS EVENING...BUT WOULD LIKE TO LOOK AT A LITTLE MORE INFORMATION BEFORE MAKING THAT FINAL CALL THIS EVENING. BRAZZELL PREV DISCUSSION... /ISSUED 310 PM CST FRI JAN 12 2007/ WINTER RETURNS WITH A VENGEANCE... SHORT TERM... A DIFFICULT FORECAST OVER THE NEXT FEW DAYS AS AN ARCTIC AIR MASS MOVES SOUTH ACROSS THE CWA. THE CHALLENGES WITH THIS FORECAST ARE HOW FAR SOUTH THE FREEZING PRECIPITATION WILL OCCUR AND HOW MUCH WILL ACCUMULATE. THERE IS A GOOD CHANCE FOR PRECIPITATION THIS WEEKEND BUT HOW FAR SOUTH THE ARCTIC FRONT PROGRESSES BEFORE IT STALLS WILL BE THE DETERMINING FACTOR. THE MODELS HAVE BEEN TOO SLOW WITH THE SOUTHWARD PROGRESSION OF THE ARCTIC FRONT...WITH THE RUC/NAM MODELS APPEARING TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT. THE FRONT IS ALREADY ALONG THE I-20 CORRIDOR AND TEMPERATURES ARE FALLING. TEMPERATURES ARE AT OR BELOW FREEZING ACROSS THE NORTHERN BIG COUNTRY AND THE RAIN THAT IS FALLING ACROSS THE BIG COUNTRY WILL CHANGE OVER TO FREEZING RAIN AFTER SUNSET. WITH THE STRONGEST LIFT ON SATURDAY NIGHT AND SUNDAY MORNING EXPECT THE LARGEST FREEZING RAIN ACCUMULATIONS TO OCCUR DURING THIS TIME PERIOD. ACROSS THE BIG COUNTRY IN GENERAL EXPECT ICE ACCUMULATIONS TONIGHT THROUGH SUNDAY TO BE BETWEEN ONE QUARTER TO ONE HALF OF INCH...SOME ISOLATED AREAS COULD SEE ICE ACCUMULATIONS UP TO ONE INCH. ACROSS THE HEARTLAND AND CONCHO VALLEY EXPECT LESS ICE ACCUMULATION TO OCCUR WITH TOTALS SATURDAY NIGHT THROUGH SUNDAY LESS THAN ONE QUARTER OF AN INCH. TEMPERATURES WILL NOT REBOUND QUICKLY SO WHAT ICE THAT ACCUMULATES WILL STAY AROUND THROUGH THE EARLY PART OF NEXT WEEK. LONG TERM... MODELS DIVERGE THE BEGINNING OF THE WEEK WITH THE GFS SHOWING AN UPPER RIDGE BUILDING INTO THE WEST COAST WITH THE MAIN LOBE OF THE UPPER TROUGH DIGGING FROM THE CENTRAL PLAINS INTO THE SOUTHWEST UNDERCUTTING THE ADVANCING WEST COAST RIDGE. GFS EVENTUALLY MERGES THIS FEATURE WITH A WEST COAST TROUGH MOVING SOUTH ALONG THE PACIFIC COAST AND RETROGRADES THE ENTIRE PACKAGE. PREFER THE NAM THAT HAS THE UPPER LEVEL TROUGH AXIS MOVING EAST OF THE AREA LATE SUNDAY AND THE WEST COAST RIDGE BUILDING EAST INTO THE WESTERN STATES. WITH THIS SCENARIO...PRECIPITATION ENDS QUICKER OVER THE FORECAST AREA WITH THE PRECIPITATION SHIELD MOVING EAST AHEAD OF THE UPPER TROUGH BY MONDAY AFTERNOON. TEMPERATURES WILL CLIMB SLOWLY THROUGH THE END OF THE WEEK TO AROUND SEASONAL NORMALS BY THE COMING WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 25 29 28 31 / 70 60 70 70 SAN ANGELO 31 36 32 40 / 60 60 70 70 JUNCTION 41 47 39 46 / 60 70 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR CALLAHAN-FISHER- HASKELL-JONES-NOLAN-SHACKELFORD-TAYLOR-THROCKMORTON. WINTER STORM WATCH FROM 6 AM CST SATURDAY THROUGH SUNDAY AFTERNOON FOR CONCHO-IRION-MCCULLOCH-SAN SABA-TOM GREEN. ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR BROWN-COKE-COLEMAN- RUNNELS-STERLING. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1105 PM CST FRI JAN 12 2007 .UPDATE...UPDATED ONCE MORE TO ACCOUNT FOR CURRENT TEMPERATURE TRENDS WHICH WERE SLIGHTLY COOLER BEHIND THE FRONT THAN FORECAST. EXTRAPOLATED TRENDS OUT THROUGH TOMORROW MORNING AND PUSHED THE FRONT A LITTLE FURTHER TO THE SOUTH OF I-10. WHILE MUCH OF THE WIDESPREAD RAIN HAS ENDED FOR THE TIME BEING...KSJT RADAR INDICATES ISENTROPIC LIFT IS INCREASING AND ECHOES ARE ONCE AGAIN BEGINNING TO INCREASE. EXPECT THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE OVERNIGHT AS NEXT DISTURBANCE IS CURRENTLY MOVING INTO THE BIG BEND REGION. PERIODIC DISTURBANCES WILL CONTINUE TO MOVE ACROSS THE REGION. FREEZING LINE PER MESONET DATA FROM ROBERT LEE TO NEAR BROWNWOOD. WHERE THE LIGHT FREEZING RAIN IS NOT OCCURRING NORTH OF THIS LINE...AREAS OF FOG AND FREEZING DRIZZLE WILL CONTINUE TO PRODUCE LIGHT ICE ACCUMULATIONS UNTIL MORE SUBSTANTIAL PRECIPITATION STARTS LATER. BRAZZELL && .PREV DISCUSSION... /ISSUED 913 PM CST FRI JAN 12 2007/ UPDATE... UPDATE IS MAINLY FOR EXTENDING THE ICE STORM WARNING ONE SET OF COUNTIES FURTHER SOUTH WHICH INCLUDES THE NORTHERN CONCHO VALLEY AND NORTHERN HEARTLAND. ARCTIC COLD FRONT IS NOW LOCATED SOUTH OF A KBWD TO KSJT LINE...AND TEMPERATURES HAVE FALLEN INTO THE MID TO UPPER 20S ACROSS THE BIG COUNTRY. STRONG SUB TROPICAL JET WITH DISTURBANCES MOVING NORTHEAST SHOULD KEEP SCATTERED AREAS OF PCPN GOING THROUGH TONIGHT. LATEST MODEL RUN INDICATING MAIN UPPER LEVEL TROF LIFTING NORTHEAST ACROSS AREA SATURDAY NIGHT AND SUNDAY...LEADING TO NEXT ROUND OF FZRA AND POSSIBLE SIGNIFICANT ICE ACCUMULATIONS ACROSS THE NORTHERN HALF OF WEST CENTRAL TEXAS. PREV DISCUSSION... /ISSUED 618 PM CST FRI JAN 12 2007/ AVIATION... WIDESPREAD PCPN CONTINUES ACROSS THE EASTERN 2/3 WEST CENTRAL TEXAS. THE PCPN IS IN THE FORM OF FZRA ACROSS THE NORTHERN BIG COUNTRY. THE ARCTIC COLD FRONT IS LOCATED NEAR A KDFW-KBWD-KSJT LINE. THE FRONT WILL CONTINUE TO MOVE SOUTH DURING TONIGHT AND SATURDAY. THERE MAY BE A BREAK IN THE PCPN LATER TONIGHT...AND THEN BECOME WIDESPREAD ON SATURDAY AS A STRONG UPPER LEVEL SYSTEM MOVES ACROSS THE ARCTIC AIRMASS OVER NORTHERN AND CENTRAL TEXAS. THE PCPN TYPE WILL REMAIN FZRA ACROSS THE BIG COUNTRY THROUGH SATURDAY...WITH POSSIBLE FZRA ALONG A KBWD TO KSJT TO MERTZON LINE ON SATURDAY. IFR CIGS OF BLO OVC010 EXPECTED ACROSS THE MUCH OF WEST CENTRAL TEXAS THROUGH 14/00Z. PREV DISCUSSION... /ISSUED 557 PM CST FRI JAN 12 2007/ UPDATE...UPDATE ALREADY ISSUED TO ACCOUNT FOR TEMEPRATURE TRENDS ALREADY COOLER THAN GRIDS. FREEZING LINE NOW APPROACHING KABI WITH SOME TROUBLE SPOTS ACROSS HASKELL AND THROCKMORTON COUNTIES ALREADY OCCURING. ANTICIPATE THAT WE MAY HAVE TO PUSH THE WARNING ONE MORE ROW OF COUNTIES TO THE SOUTH THIS EVENING...BUT WOULD LIKE TO LOOK AT A LITTLE MORE INFORMATION BEFORE MAKING THAT FINAL CALL THIS EVENING. BRAZZELL PREV DISCUSSION... /ISSUED 310 PM CST FRI JAN 12 2007/ WINTER RETURNS WITH A VENGEANCE... SHORT TERM... A DIFFICULT FORECAST OVER THE NEXT FEW DAYS AS AN ARCTIC AIR MASS MOVES SOUTH ACROSS THE CWA. THE CHALLENGES WITH THIS FORECAST ARE HOW FAR SOUTH THE FREEZING PRECIPITATION WILL OCCUR AND HOW MUCH WILL ACCUMULATE. THERE IS A GOOD CHANCE FOR PRECIPITATION THIS WEEKEND BUT HOW FAR SOUTH THE ARCTIC FRONT PROGRESSES BEFORE IT STALLS WILL BE THE DETERMINING FACTOR. THE MODELS HAVE BEEN TOO SLOW WITH THE SOUTHWARD PROGRESSION OF THE ARCTIC FRONT...WITH THE RUC/NAM MODELS APPEARING TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT. THE FRONT IS ALREADY ALONG THE I-20 CORRIDOR AND TEMPERATURES ARE FALLING. TEMPERATURES ARE AT OR BELOW FREEZING ACROSS THE NORTHERN BIG COUNTRY AND THE RAIN THAT IS FALLING ACROSS THE BIG COUNTRY WILL CHANGE OVER TO FREEZING RAIN AFTER SUNSET. WITH THE STRONGEST LIFT ON SATURDAY NIGHT AND SUNDAY MORNING EXPECT THE LARGEST FREEZING RAIN ACCUMULATIONS TO OCCUR DURING THIS TIME PERIOD. ACROSS THE BIG COUNTRY IN GENERAL EXPECT ICE ACCUMULATIONS TONIGHT THROUGH SUNDAY TO BE BETWEEN ONE QUARTER TO ONE HALF OF INCH...SOME ISOLATED AREAS COULD SEE ICE ACCUMULATIONS UP TO ONE INCH. ACROSS THE HEARTLAND AND CONCHO VALLEY EXPECT LESS ICE ACCUMULATION TO OCCUR WITH TOTALS SATURDAY NIGHT THROUGH SUNDAY LESS THAN ONE QUARTER OF AN INCH. TEMPERATURES WILL NOT REBOUND QUICKLY SO WHAT ICE THAT ACCUMULATES WILL STAY AROUND THROUGH THE EARLY PART OF NEXT WEEK. LONG TERM... MODELS DIVERGE THE BEGINNING OF THE WEEK WITH THE GFS SHOWING AN UPPER RIDGE BUILDING INTO THE WEST COAST WITH THE MAIN LOBE OF THE UPPER TROUGH DIGGING FROM THE CENTRAL PLAINS INTO THE SOUTHWEST UNDERCUTTING THE ADVANCING WEST COAST RIDGE. GFS EVENTUALLY MERGES THIS FEATURE WITH A WEST COAST TROUGH MOVING SOUTH ALONG THE PACIFIC COAST AND RETROGRADES THE ENTIRE PACKAGE. PREFER THE NAM THAT HAS THE UPPER LEVEL TROUGH AXIS MOVING EAST OF THE AREA LATE SUNDAY AND THE WEST COAST RIDGE BUILDING EAST INTO THE WESTERN STATES. WITH THIS SCENARIO...PRECIPITATION ENDS QUICKER OVER THE FORECAST AREA WITH THE PRECIPITATION SHIELD MOVING EAST AHEAD OF THE UPPER TROUGH BY MONDAY AFTERNOON. TEMPERATURES WILL CLIMB SLOWLY THROUGH THE END OF THE WEEK TO AROUND SEASONAL NORMALS BY THE COMING WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 25 29 28 / 50 70 60 70 SAN ANGELO 67 31 36 32 / 50 60 60 70 JUNCTION 67 41 47 39 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR CALLAHAN-FISHER- HASKELL-JONES-NOLAN-SHACKELFORD-TAYLOR-THROCKMORTON. WINTER STORM WATCH FROM 6 AM CST SATURDAY THROUGH SUNDAY AFTERNOON FOR CONCHO-IRION-MCCULLOCH-SAN SABA-TOM GREEN. ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR BROWN-COKE-COLEMAN- RUNNELS-STERLING. && $$ 27/27 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 720 AM CST SAT JAN 13 2007 .UPDATE... LATEST RADAR DATA SHOWS SOME IMPRESSIVE RETURNS OVER NORTHERN OKLAHOMA MOVING NORTHEAST INTO SOUTHERN KANSAS...MOST LIKELY AREAS OF VERY HEAVY SLEET. LOCAL 12Z RAOB SOUNDINGS SUGGEST MAINLY SLEET FOR PRECIP TYPE ACROSS SOUTHERN KANSAS WITH A POSSIBLE CHANGE OVER TO SNOW LATER IN THE DAY. IR SATELLITE IMAGERY ACTUALLY SHOWED A FEW POCKETS OF WARMER TEMPS OVER CENTRAL AND SOUTH CENTRAL KANSAS EARLY THIS MORNING...THIS CREATED A VOID OF ICE CRYSTALS IN THE THERMAL PROFILE AND RESULTANT PRECIP WAS FREEZING DRIZZLE...HOWEVER WE EXPECT MORE SLEET AND SNOW DURING THE DAY AS COOLER CLOUD TOPS MOVE ACROSS THE REGION. SLEET ACCUMULATION IS LIKELY ACROSS SOUTHERN KANSAS WITH SOME LOCATIONS WITNESSING AN INCH OR MORE OF SLEET. MEANWHILE...A BUBBLE OF WARMER AIR ALOFT WAS PRESENT OVER CENTRAL OKLAHOMA EXTENDING NORTHWARD INTO SOUTHEAST KANSAS. THIS COULD YIELD ANOTHER EPISODE OF FREEZING RAIN ACROSS SOUTHEAST KANSAS. AS A RESULT...WE WILL INSERT A FREEZING RAIN/SLEET MIX FOR TODAY OVER THAT AREA. JAKUB && .PREV DISCUSSION... /ISSUED 508 AM CST SAT JAN 13 2007/ UPDATE... WE JUST SENT OUT A QUICK UPDATE TO INTRODUCE SLEET AND SNOW MIX THROUGH ABOUT 14Z. JUST MADE A COUPLE OF CALLS TO HARPER AND RUSSELL COUNTIES AND THEY ARE REPORTING SLEET THAT IS COVERING THE GROUND. THIS PRECIPITATION APPEARS TO BE ON THE LEADING EDGE OF THE WAVE MOVING ACROSS THE TEXAS PANHANDLE. LATEST IR SATELLITE LOOP IS SHOWING HIGHER TOPS MOVING ACROSS THAT REGION WHICH IS AN INDICATION OF MORE GROWTH IN THE DENDRITE REGION WHICH WOULD SUPPORT MORE IN THE WAY OF SNOW. AS A RESULT...IT STILL LOOKS LIKE WE COULD GET SOME DECENT SNOW LATE THIS MORNING INTO THE AFTERNOON. COX DISCUSSION... WE JUST SENT OUT A QUICK UPDATE TO INTRODUCE SLEET AND SNOW MIX THROUGH ABOUT 14Z. JUST MADE A COUPLE OF CALLS TO HARPER AND RUSSELL COUNTIES AND THEY ARE REPORTING SLEET THAT IS COVERING THE GROUND. THIS PRECIPITATION APPEARS TO BE ON THE LEADING EDGE OF THE WAVE MOVING ACROSS THE TEXAS PANHANDLE. LATEST IR SATELLITE LOOP IS SHOWING HIGHER TOPS MOVING ACROSS THAT REGION WHICH IS AN INDICATION OF MORE GROWTH IN THE DENDRITE REGION WHICH WOULD SUPPORT MORE IN THE WAY OF SNOW. AS A RESULT...IT STILL LOOKS LIKE WE COULD GET SOME DECENT SNOW LATE THIS MORNING INTO THE AFTERNOON. PREV DISCUSSION... /ISSUED 331 AM CST SAT JAN 13 2007/ DISCUSSION... THE MAIN CONCERN FOR TODAY THROUGH SUNDAY WILL BE PRECIPITATION TYPE AND HOW MUCH SNOW OR ICE WILL BE POSSIBLE DURING THE NEXT COUPLE OF DAYS. TODAY: LATEST IR LOOP AND SURFACE ANALYSIS SHOWING A FAIRLY STRONG WAVE MOVING THROUGH THE TEXAS PANHANDLE WITH EVEN SOME LIGHTNING STRIKES ASSOCIATED WITH IT. THIS WAVE WILL CONTINUE TO LIFT NORTHEAST THIS MORNING AND INCREASE THE ISENTROPIC ASCENT MARKEDLY ACROSS THE FORECAST AREA TODAY. THE 00Z GFS/RUC SEEM TO HANDLE THE STRENGTH OF THIS WAVE BASED ON THE IR AND WATER VAPOR LOOPS. AS A RESULT...WE ARE FAVORING THESE SOLUTIONS FOR THE POTENTIAL FOR SOME DECENT SNOW AND SLEET ACCUMULATIONS TODAY. WE ARE MAKING SOME ADJUSTMENTS TO THE PRECIPITATION TYPE OVER THE ENTIRE AREA SINCE IT APPEARS LIKE MOST OF BOUNDARY LAYER TEMPERATURES AROUND -10 DEG C WHICH IS SUPPORTIVE OF PRECIPITATION REFREEZING BEFORE IT REACHES THE GROUND. THEREFORE...WE ARE LOOKING AT MORE OF A SNOW OR SLEET POTENTIAL ACROSS SOUTHEAST KANSAS TODAY. THE MAIN CONCERN RIGHT NOW...IS SOUTH CENTRAL KANSAS WHERE THEY COULD SEE MORE IN THE WAY OF SNOW WITH ACCUMULATIONS UP TO 4 INCHES BY LATE AFTERNOON. THE GFS DOES SHOW SOME COOLING AROUND 700MB DUE TO LATENT HEAT PROCESS...BUT WE BELIEVE IT MAY NOT BE COOLING THAT COLUMN ENOUGH DUE TO SUCH STRONG LIFT IN THAT REGION. THE COBB TECHNIQUE IS ALSO SUPPORTIVE OF THIS. MEANWHILE...FOLKS IN CENTRAL KANSAS COULD SEE AT LEAST 2 INCHES OF SNOW. WE WENT AHEAD AND UPGRADED THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING AND CONTINUED IT THROUGH SUNDAY SINCE WE ARE ANTICIPATING THIS WHOLE EVENT TO PRODUCE 6 INCHES OF SNOW OR MORE OVER MOST OF CENTRAL AND SOUTH CENTRAL KANSAS. THE WINTER STORM WARNING STILL LOOKS GOOD FOR THE REMAINDER OF THE AREA SINCE THE SLEET AND SNOW ACCUMULATIONS WILL BE SIGNIFICANT. TONIGHT-SUNDAY: THE MODELS ARE ADVERTISING ANOTHER BREAK IN THE PRECIPITATION THIS EVENING...BEFORE THE MAIN UPPER TROF MOVES INTO THE WESTERN SECTIONS OF OUR FORECAST AREA OVERNIGHT. THIS TROF SHOULD BRING ANOTHER ROUND OF SNOW AND SLEET TO THE AREA WITH THE BEST CHANCE OF SNOW ACROSS CENTRAL AND SOUTH CENTRAL KANSAS WHERE ANOTHER 2 TO 5 INCHES OF SNOW WILL BE POSSIBLE BY SUNDAY EVENING WITH THE HIGHEST AMOUNTS EXPECTED TO BE IN CENTRAL KANSAS WHERE THEY WILL BE CLOSEST TO THE MID LEVEL BAROCLINIC ZONE. THERE WILL ALSO BE SOME AID FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET WHICH WILL INCREASE THE ISENTROPIC ASCENT WITH ADDITIONAL LIFT FROM MID LEVEL FRONTOGENETICAL CIRCULATIONS. WE MAY END UP INCREASING SNOW AMOUNTS EVEN MORE IN LATER FORECASTS. SUNDAY NIGHT-WEDNESDAY: WE SHOULD BEGIN TO SEE THE SNOW MOVING OUT OF THE PICTURE SUNDAY NIGHT. THEN THE ARCTIC HIGH WILL BEGIN TO SETTLE OVER US DURING THE NEXT COUPLE OF DAYS. WE LOWERED HIGHS AND LOWS SEVERAL DEGREES ESPECIALLY ON MONDAY AND TUESDAY WHERE THE SURFACE RIDGE BEGINS TO PARK OVER THE AREA. WITH LOTS OF SNOW COVER AND NORTHERLY FLOW OVER US...WE WILL BE HARD PRESSED TO MAKE INTO THE 20S WITH LOWS POSSIBLY DROPPING BELOW ZERO. COX && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 20 15 19 10 / 100 70 100 40 HUTCHINSON 18 14 17 8 / 100 70 100 40 NEWTON 19 14 18 9 / 100 50 100 40 ELDORADO 20 14 18 10 / 100 50 100 40 WINFIELD-KWLD 20 15 19 12 / 100 70 100 30 RUSSELL 15 10 14 5 / 100 70 100 50 GREAT BEND 17 12 16 6 / 100 80 100 50 SALINA 18 14 17 7 / 100 40 100 50 MCPHERSON 18 14 17 7 / 100 50 100 40 COFFEYVILLE 22 19 23 16 / 100 60 100 30 CHANUTE 21 17 21 14 / 100 60 100 40 IOLA 21 17 21 13 / 100 60 100 40 PARSONS-KPPF 21 19 22 15 / 100 60 100 30 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM CST SUNDAY FOR KSZ032-033- 047>053-067>072-082-083-091>096-098>100. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 508 AM CST SAT JAN 13 2007 .UPDATE... WE JUST SENT OUT A QUICK UPDATE TO INTRODUCE SLEET AND SNOW MIX THROUGH ABOUT 14Z. JUST MADE A COUPLE OF CALLS TO HARPER AND RUSSELL COUNTIES AND THEY ARE REPORTING SLEET THAT IS COVERING THE GROUND. THIS PRECIPITATION APPEARS TO BE ON THE LEADING EDGE OF THE WAVE MOVING ACROSS THE TEXAS PANHANDLE. LATEST IR SATELLITE LOOP IS SHOWING HIGHER TOPS MOVING ACROSS THAT REGION WHICH IS AN INDICATION OF MORE GROWTH IN THE DENDRITE REGION WHICH WOULD SUPPORT MORE IN THE WAY OF SNOW. AS A RESULT...IT STILL LOOKS LIKE WE COULD GET SOME DECENT SNOW LATE THIS MORNING INTO THE AFTERNOON. COX && .DISCUSSION... WE JUST SENT OUT A QUICK UPDATE TO INTRODUCE SLEET AND SNOW MIX THROUGH ABOUT 14Z. JUST MADE A COUPLE OF CALLS TO HARPER AND RUSSELL COUNTIES AND THEY ARE REPORTING SLEET THAT IS COVERING THE GROUND. THIS PRECIPITATION APPEARS TO BE ON THE LEADING EDGE OF THE WAVE MOVING ACROSS THE TEXAS PANHANDLE. LATEST IR SATELLITE LOOP IS SHOWING HIGHER TOPS MOVING ACROSS THAT REGION WHICH IS AN INDICATION OF MORE GROWTH IN THE DENDRITE REGION WHICH WOULD SUPPORT MORE IN THE WAY OF SNOW. AS A RESULT...IT STILL LOOKS LIKE WE COULD GET SOME DECENT SNOW LATE THIS MORNING INTO THE AFTERNOON. && .PREV DISCUSSION... /ISSUED 331 AM CST SAT JAN 13 2007/ DISCUSSION... THE MAIN CONCERN FOR TODAY THROUGH SUNDAY WILL BE PRECIPITATION TYPE AND HOW MUCH SNOW OR ICE WILL BE POSSIBLE DURING THE NEXT COUPLE OF DAYS. TODAY: LATEST IR LOOP AND SURFACE ANALYSIS SHOWING A FAIRLY STRONG WAVE MOVING THROUGH THE TEXAS PANHANDLE WITH EVEN SOME LIGHTNING STRIKES ASSOCIATED WITH IT. THIS WAVE WILL CONTINUE TO LIFT NORTHEAST THIS MORNING AND INCREASE THE ISENTROPIC ASCENT MARKEDLY ACROSS THE FORECAST AREA TODAY. THE 00Z GFS/RUC SEEM TO HANDLE THE STRENGTH OF THIS WAVE BASED ON THE IR AND WATER VAPOR LOOPS. AS A RESULT...WE ARE FAVORING THESE SOLUTIONS FOR THE POTENTIAL FOR SOME DECENT SNOW AND SLEET ACCUMULATIONS TODAY. WE ARE MAKING SOME ADJUSTMENTS TO THE PRECIPITATION TYPE OVER THE ENTIRE AREA SINCE IT APPEARS LIKE MOST OF BOUNDARY LAYER TEMPERATURES AROUND -10 DEG C WHICH IS SUPPORTIVE OF PRECIPITATION REFREEZING BEFORE IT REACHES THE GROUND. THEREFORE...WE ARE LOOKING AT MORE OF A SNOW OR SLEET POTENTIAL ACROSS SOUTHEAST KANSAS TODAY. THE MAIN CONCERN RIGHT NOW...IS SOUTH CENTRAL KANSAS WHERE THEY COULD SEE MORE IN THE WAY OF SNOW WITH ACCUMULATIONS UP TO 4 INCHES BY LATE AFTERNOON. THE GFS DOES SHOW SOME COOLING AROUND 700MB DUE TO LATENT HEAT PROCESS...BUT WE BELIEVE IT MAY NOT BE COOLING THAT COLUMN ENOUGH DUE TO SUCH STRONG LIFT IN THAT REGION. THE COBB TECHNIQUE IS ALSO SUPPORTIVE OF THIS. MEANWHILE...FOLKS IN CENTRAL KANSAS COULD SEE AT LEAST 2 INCHES OF SNOW. WE WENT AHEAD AND UPGRADED THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING AND CONTINUED IT THROUGH SUNDAY SINCE WE ARE ANTICIPATING THIS WHOLE EVENT TO PRODUCE 6 INCHES OF SNOW OR MORE OVER MOST OF CENTRAL AND SOUTH CENTRAL KANSAS. THE WINTER STORM WARNING STILL LOOKS GOOD FOR THE REMAINDER OF THE AREA SINCE THE SLEET AND SNOW ACCUMULATIONS WILL BE SIGNIFICANT. TONIGHT-SUNDAY: THE MODELS ARE ADVERTISING ANOTHER BREAK IN THE PRECIPITATION THIS EVENING...BEFORE THE MAIN UPPER TROF MOVES INTO THE WESTERN SECTIONS OF OUR FORECAST AREA OVERNIGHT. THIS TROF SHOULD BRING ANOTHER ROUND OF SNOW AND SLEET TO THE AREA WITH THE BEST CHANCE OF SNOW ACROSS CENTRAL AND SOUTH CENTRAL KANSAS WHERE ANOTHER 2 TO 5 INCHES OF SNOW WILL BE POSSIBLE BY SUNDAY EVENING WITH THE HIGHEST AMOUNTS EXPECTED TO BE IN CENTRAL KANSAS WHERE THEY WILL BE CLOSEST TO THE MID LEVEL BAROCLINIC ZONE. THERE WILL ALSO BE SOME AID FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET WHICH WILL INCREASE THE ISENTROPIC ASCENT WITH ADDITIONAL LIFT FROM MID LEVEL FRONTOGENETICAL CIRCULATIONS. WE MAY END UP INCREASING SNOW AMOUNTS EVEN MORE IN LATER FORECASTS. SUNDAY NIGHT-WEDNESDAY: WE SHOULD BEGIN TO SEE THE SNOW MOVING OUT OF THE PICTURE SUNDAY NIGHT. THEN THE ARCTIC HIGH WILL BEGIN TO SETTLE OVER US DURING THE NEXT COUPLE OF DAYS. WE LOWERED HIGHS AND LOWS SEVERAL DEGREES ESPECIALLY ON MONDAY AND TUESDAY WHERE THE SURFACE RIDGE BEGINS TO PARK OVER THE AREA. WITH LOTS OF SNOW COVER AND NORTHERLY FLOW OVER US...WE WILL BE HARD PRESSED TO MAKE INTO THE 20S WITH LOWS POSSIBLY DROPPING BELOW ZERO. COX && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 20 15 19 10 / 100 70 100 40 HUTCHINSON 18 14 17 8 / 100 70 100 40 NEWTON 19 14 18 9 / 100 80 100 40 ELDORADO 20 14 18 10 / 100 90 100 40 WINFIELD-KWLD 20 15 19 12 / 100 80 100 30 RUSSELL 15 10 14 5 / 100 70 100 50 GREAT BEND 17 12 16 6 / 100 80 100 50 SALINA 18 14 17 7 / 100 80 100 50 MCPHERSON 18 14 17 7 / 100 70 100 40 COFFEYVILLE 22 19 23 16 / 100 100 100 30 CHANUTE 21 17 21 14 / 100 100 100 40 IOLA 21 17 21 13 / 100 100 100 40 PARSONS-KPPF 21 19 22 15 / 100 100 100 30 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM CST SUNDAY FOR KSZ032-033- 047>053-067>072-082-083-091>096-098>100. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1016 AM EST SAT JAN 13 2007 .MORNING UPDATE (THIS AFTERNOON/TONIGHT)... CURRENT MORNING SFC ANALYSIS REVEALS COLD FRONT FROM NEAR CMH SW TO JUST WEST OF MEM. PRETTY GOOD TEMPERATURE GRADIENT NOTED ACROSS THE FAR NW PORTION OF THE DISTRICT WITH READINGS IN THE MID AND UPPER 50S ACROSS MUCH OF THE FA...BUT UP NEAR JASPER TEMPERATURES HAVE DROPPED INTO THE MID 40S. AREA RADARS SHOWING NEXT ROUND OF LIGHT TO MODERATE RAIN MOVING IN FROM THE WEST WHICH WILL PASS THROUGH THE FA THIS AFTERNOON. EASTERN SECTIONS WILL SEE A GENERAL DOWNWARD TREND IN PRECIPITATION LATE THIS MORNING BEFORE INCREASING AGAIN IN THE AFTERNOON. LOOKING AT THE LATEST SHORT TERM GUIDANCE...THE RUC MODELS (13KM/40KM) SEEM TO HAVE A VERY GOOD HANDLE ON TEMPERATURES THIS MORNING. THE RUC MODELS SEEM TO BRING THE FRONT TO ABOUT LOUISVILLE LATE THIS EVENING AND THEN STALLING IT OUT. THE NET RESULT WOULD BE TEMPERATURES ACROSS OUR SOUTHERN INDIANA COUNTIES WOULD FALL DURING THE AFTERNOON INTO THE MID AND UPPER 40S WITH ALL OF THE KY COUNTIES TEMPERATURES HOLDING STEADY IN THE MID TO UPPER 50S. CURRENT FORECAST IS GOOD SHAPE RIGHT NOW...BUT WILL NEED TO MAKE SOME MINOR ADJUSTMENTS TO THE TEMP GRIDS TO REFLECT CURRENT RUC TRENDS. ON THE HYDROLOGICAL SIDE...AT THE PRESENT TIME WE ARE IN GOOD SHAPE. THE LIGHT TO MODERATE RAINS THUS FAR HAVE NOT RESULTED IN EXCESSIVE RUNOFF. HOWEVER...MAIN BULK OF PRECIPITATION ACCUMULATION IS FORECAST TO IMPACT THE REGION LATE TONIGHT AND ON SUNDAY. THEREFORE...CURRENT FLOOD WATCH WILL REMAIN IN EFFECT. UPDATED FORECAST SUITE WILL BE AVAILABLE BY 1100 AM EST. -MJ PREVIOUS DISCUSSION FOLLOWS... .SHORT TERM (TODAY AND TONIGHT)... CURRENTLY...DEEP SWRLY FLOW IS DOMINATING ACROSS THE REGION. A COLD FRONT IS QUICKLY APPROACHING FROM THE WEST AND IS PUSHING THROUGH EVV ATTM. LOW-LEVEL COLD AIR IS FILTERING IN BEHIND THE FRONT FASTER THAN MODELS HAD ANTICIPATED. LARGE AMOUNT OF ISENTROPIC LIFT OVER THE COLD AIR HAS LED TO QUITE AN ICING EVENT OVER PORTIONS OF OK INTO MO. LARGE TEMP GRADIENT PRESENT AS WELL...AS PAH WAS AT 60 DEGREES AND CAPE GIRARDEAU AT 39 DEGREES AT 2AM EST. DESPITE COLD FRONT QUICKLY APPROACHING...A LOW PRESSURE WAVE OVER THE TEXARKANA REGION RIDING NEWD ALONG THE FRONT WILL HELP SLOW THE FRONT`S PROGRESSION...AND WILL BE RESPONSIBLE FOR OUR FIRST WAVE OF POTENTIALLY HEAVY PRECIP...WHICH IS CURRENTLY OVER WRN KY. THIS AREA SHOULD EXPAND AND FILTER INTO OUR CWA THROUGHOUT THE MORNING. MAY EVEN SEE A RUMBLE OF THUNDER OR TWO WITH THIS FIRST BATCH OF RAINFALL GIVEN UPSTREAM TRENDS. WILL ONLY MENTION ISLD THREAT WEST OF I-65 THIS MORNING. AFTER THIS MORNING`S MAIN AREA OF PRECIP...A LULL IN THE PRECIP SHOULD OCCUR THIS AFTERNOON BEFORE ANOTHER LOW PRESSURE WAVE RIDES NEWD ALONG THE FRONT TONIGHT...CAUSING ANOTHER BOUT OF POTENTIALLY HEAVY RAIN. THOUGH RAIN ONSET IS LATER THAN ANTICIPATED...STILL THINK THE FLOOD WATCH IS WARRANTED THROUGH THE WEEKEND. PWATS ARE OVER AN INCH NOW...AND NAM BUFKIT SOUNDINGS INDICATE NEAR 1.5 INCHES THIS EVENING...WHICH IS SUPPORTED BY THE 4-5 STD DEVIATIONS ABV NORMAL POSED BY THE SHORT-RANGE ENSEMBLES. ALSO...NAM AND GFS INDICATE SOME ELEVATED INSTABILITY WITH LI`S AROUND ZERO TONIGHT...WHICH WILL AID IN OVERALL PRECIP AMOUNTS GIVEN THIS CONVECTION. STILL THINK SOME LOCATIONS COULD SEE 2-3 INCHES OF RAINFALL...WITH ISOLATED LOCATIONS SEEING 4 INCHES OR MORE. HOWEVER...GIVEN THE SLOW ONSET THINK A WIDESPREAD FLOODING EVENT IS NOT LIKELY...THOUGH A MINOR AND MORE ISOLATED FLOODING EVENT IS CERTAINLY POSSIBLE...SO WILL CONTINUE FLOOD WATCH. MAY DOWN PLAY AMOUNTS A WEE BIT BUT THAT IS ALL. THE FRONT WILL BE CLOSELY ALIGNED WITH THE OHIO RIVER AROUND SUNRISE AND SHOULD BE IN NEARLY THE SAME LOCATION OR JUST SE BY MIDNIGHT TONIGHT. WILL KEEP CATEGORICAL POPS GOING...WITH MENTION OF LOCALLY HEAVY RAINFALL. FOR AVIATION CONCERNS...HAVE LOW-LEVEL WIND SHEAR IN ALL THE TAF SITES THIS MORNING GIVEN THE STRONG SWRLY JET OF 40-45 KTS OVER THE CWA NOW...EVIDENT FROM AREA VWPS AND SDF ACARS SOUNDINGS. MAY SEE SOME GUSTY WINDS HERE AND THERE...BUT NOTHING OUT OF HAND AS CLOUDY SKIES SHOULD HELP INHIBIT LARGER GUSTS. TEMPS WILL BE TRICKY TODAY...AND COULD HAVE QUITE THE GRADIENT ACROSS THE CWA...ESPECIALLY BY MIDDAY. TEMPS MAY DROP AND/OR STEADY OUT ACROSS THE NW...WITH CURRENT READINGS IN THE UPPER 50S DROPPING TO THE UPPER 40S AND HOLDING THERE. THE SERN CWA COULD SEE HIGHS A FEW DEGREES WARMER THAN CURRENT READINGS...AND SHOULD STICK AROUND 60 FOR THE MOST PART. OVERNIGHT LOWS WILL NOT BUDGE MUCH AND SHOULD BE JUST A FEW DEGREES COLDER THAN HIGHS TODAY. AL .LONG TERM (SUNDAY THROUGH FRIDAY)... SUNDAY AND MONDAY... FORECAST CHALLENGE WILL BE PLACEMENT OF THE COLD FRONT AT THE BEGINNING OF THIS PERIOD. LATEST SHORT RANGE MODELS DID NOT INITIALIZE SHALLOW COLD AIR WELL AND FEEL IT WILL BE FURTHER SOUTH THAN MODELS SUGGEST. SURFACE WAVE SHOULD SHIFT THE COLD AIR NORTH SOME DURING THE AFTERNOON SUNDAY AND AT THIS TIME WE WILL KEEP PRECIPITATION ACROSS THE NORTH IN THE FORM OF RAIN. THE AXIS OF HEAVY RAIN SUNDAY AND SUNDAY NIGHT STILL LOOKS TO BE ALONG THE OHIO RIVER WHERE AN INCH TO AN INCH AND A HALF WILL BE POSSIBLE. LIGHTEST AMOUNTS WILL OCCUR ACROSS THE SOUTHEAST PORTION OF THE COUNTY FORECAST AREA. WE WILL HOLD ONTO ISOLATED THUNDERSTORMS SOUTH OF THE OHIO RIVER SUNDAY WHERE BEST DYNAMICS EXIST...ALTHOUGH INSTABILITY WILL BE LACKING. TEMPERATURES WILL BE A CONCERN AS WELL AS A 10 TO 15 DEGREE GRADIENT WILL BE NOTED ACROSS THE COLD FRONT. HIGHS SUNDAY WILL TOP OUT IN THE LOWER 40S ACROSS SOUTHERN INDIANA WITH UPPER 50S EXPECTED NEAR THE TENNESSEE BORDER. ONCE THE SURFACE LOW MOVES NORTHEAST OF THE REGION THE MODIFIED ARCTIC AIR WILL ENTER THE FORECAST AREA MONDAY. HIGHEST TEMPERATURES WILL OCCUR DURING THE MORNING. LIGHT SNOW SHOWERS WILL BE POSSIBLE MONDAY BUT NO ACCUMULATION IS EXPECTED. JA TUESDAY THROUGH FRIDAY... NOT MUCH CHANGE IN THE FORECAST THROUGH THIS TIME PERIOD. WITH FRONT CONTINUING TO OUR SOUTH AND HIGH PRESSURE BUILDING IN FROM THE UPPER PLAINS...NORTHERLY WINDS WILL GET THE LAKE-EFFECT SNOW MACHINE GOING TO OUR NORTH. DOWN THIS FAR SOUTH...FEEL THAT SCT FLURRIES WILL BE POSSIBLE DURING THE DAY ON TUESDAY AND WILL LEAVE AS SUCH. BETTER CHC FOR SNOW SHOWERS WOULD EXIST OVER FAR EAST KY IN THE FAVORED UPSLOPE REGIONS. DRY FORECAST IS ANTICIPATED FOR WEDNESDAY THROUGH FRIDAY AS HIGH PRESSURE CONTINUES TO BUILD OVER THE REGION. TEMPERATURES AT THE BEGINNING OF THIS PD WILL BE WELL BELOW NORMAL WITH HIGHS IN THE UPPER 20S TO LOWER 30S AND OVERNIGHT LOWS IN THE UPPER TEENS. SOME MODERATION IN THE TEMPERATURES WILL OCCUR BY THURSDAY AND FRIDAY WITH TEMPERATURES WARMING SLIGHTLY INTO THE MID AND UPPER 30S. GENERALLY STUCK CLOSE TO THE HPC GUIDANCE THROUGH THIS PERIOD. MJ && .LMK WATCHES/WARNINGS/ADVISORIES... KY...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR KYZ023>043-045>049- 053>057-061>067-070>078-081-082. IN...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR INZ076>079-083-084- 089>092. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 556 AM CST SAT JAN 13 2007 .DISCUSSION... ...ICE STORM WARNING CONTINUES ACROSS MUCH OF THE REGION THROUGH SUNDAY NIGHT... THE FIRST WAVE OF THE STORM HAS PRODUCED A PRETTY GOOD HIT ON THE AREA. IF THERE IS ANY SAVING GRACE IT IS THAT A GOOD DEAL OF THE PCPN ACRS NE MO/WEST CENTRAL IL INTO CENTRAL MO HAS BEEN IN THE FORM OF SLEET AND THIS HAS REDUCED THE AMOUNT OF ICE GLAZE FROM FREEZING RAIN. SLEET HAS BEEN REPORTED AS FAR EAST AS TROY AND WARRENTON. OUR BEST ESTIMATE FROM SPOTTER REPORTS IS THE ZR ICE GLAZE RANGES FROM AROUND ONE-QUARTER INCH FROM WESTERN ST LOUIS METRO UPWARDS TO A HALF-INCH HEADING TOWARDS COLUMBIA. WE ARE GETTING REPORTS OF DOWNED TREES AND POWER LINES AND ASSOCIATED POWER OUTAGES WITHIN THIS CORRIDOR. THE CURRENT SOLID WAVE OF PCPN IS SHOWING A DECIDED BACK EDGE...RUNNING THRU NE AND CNTRL MO. THIS WAVE OF PCPN SHOULD CONT TO SHIFT EAST THIS MORNING...AND BELIEVE IT WILL EXIT MOST OF THE REGION WITH MAYBE THE EXCEPTION OF FAR SE MO AND SRN IL BY MID MORNING. WEAK LOW LEVEL CAA IS CONTINUING WITH THE NNWLY WINDS ACROSS THE REGION... AND KFAM IS NOW DOWN TO FREEZING. AS A RESULT HAVE ISSUED A FREEZING RAIN ADVISORY TODAY FOR THE REGION FROM FARMINGTON TO SPARTA TO NASHVILLE. ADDITIONAL ICE GLAZE THIS MORNING EXPECTED TO REMAIN LESS THAN A QUARTER INCH OVER PORTIONS OF ECNTRL MO INTO SW IL. AFTER THIS MAIN BATCH OF PCPN EXITS EAST...THINK WE WILL ONLY SEE PERIODIC BATCHES OF LIGHT PCPN SKIRT ACROSS THE AREA...NOTHING LIKE THE INTENSITY WE HAVE SEEN THE LAST 18H OR SO. THIS SHOULD CONTRIBUTE NO MORE THAN A LIGHT ICE GLAZE. EXPECTING PCPN TNGT WILL ALSO BE RELATIVELY LIGHT WITHIN THE COLD AIR...WITH THE HEAVIEST PCPN HAVING SHIFTED S AND SE OF THE CWFA. ONCE AGAIN ANY ADDITIONAL ICE GLAZE TONIGHT WILL BE LIGHT. THE FINAL ROUND OF PCPN ASSOCIATED WITH THIS PROLONGED EVENT WILL IMPACT THE REGION ON SUNDAY AS STRONG LARGE SCALE ASCENT OVERSPREADS THE REGION IN ASSOCIATION WITH THE EJECTING MID-UPR LEVEL TROF. THIS ROUND OF THE STORM SHOULD BE AS BAD OR WORSE THAN THIS FIRST WAVE WE HAVE BEEN EXPERIENCING WITH WDSPRD PCPN AMOUNTS OF AT LEAST ONE- HALF INCH. MODEL SOUNDINGS AND P-TYPE ALGORITHMS SHOW THE MAJORITY OF THE PCPN FROM CENTRAL MO INTO WEST CENTRAL IL SHOULD BE IN THE FORM OF SLEET. SIGNIFICANT ICING FROM FREEZING RAIN LIKELY IN MUCH THE SAME LOCATION WE HAVE JUST EXPERIENCED...NAMELY ST LOUIS METRO TO ABOUT 50 MILES WEST. ADDITIONAL ICE ACCUMS OF AROUND ONE-HALF INCH APPEAR QUITE REASONABLE GIVEN QPF IN THE .50-.75 RANGE. THIS ADDITIONAL ICE ACCUMULATION ALONG WITH GUSTY NW WINDS LATE SUNDAY NIGHT AND MONDAY COULD BE DEVASTATING GIVEN OUR CURRENT SITUATION WITH ICE ALREADY WEIGHING HEAVILY ON TREES AND POWER LINES. THE POTENTIAL FOR WIDESPREAD POWER OUTAGES ACROSS EASTERN MO INTO WESTERN ILLINOIS IS VERY REAL. ACROSS NE MO INTO WEST CENTRAL ILLINOIS THE COLD AIR SHOULD DEEPEN ENUF BY SUNDAY EVENING FOR A BAND OF 2-3 INCHES OF SNOW. FINALLY...THE RAIN HAS BEGUN TO IMPACT SOME OF THE RIVERS AND STREAMS ACROSS SRN MO. WE HAVE SOME REPORTS OF THE TYPICAL FLOODED LOW WATER CROSSINGS AND THE RIVERS SHOULD BEGIN TO RESPOND TODAY. THUS THE FLOOD WATCH STILL LOOKS QUITE GOOD IN THIS AREA. A SIDE NOTE - THE NORMAL MODEL GUIDANCE SUITE OF THE GFS AND NAM CONTINUES TO HAVE PROBLEMS WITH THE INTENSITY AND EXTENT OF THE COLD AIR. THE OPERATIONAL RUC AND DEVELOPMENTAL RUC THROUGH 48H APPEAR TO HAVE THE BEST HANDLE ON THE SURFACE TEMPERATURE PROFILE. GLASS && .AVIATION... FOR THE 12Z TAFS...FREEZING RAIN AND SLEET HAS FINALLY ENDED IN UIN AND COU. LOOKING AT RADAR TRENDS PCPN SHOULD BE PULLING E OF STL AND SUS BY 14Z SAT. ALTHOUGH THE P TYPE HAS BEEN FZRA IN STL AND SUS THRU THE LT NGT HRS...INCLUDED A TEMPO GRP OF PL TIL 14Z AS WFO LSX JUST W OF SUS HAS BEEN EXPERIENCING BOTH FZRA AND PL DURING THE LAST HR. CEILING HGTS SHOULD RISE SLIGHTLY LTR THIS MRNG TO ARND 1500-2000 FT WITH NLY SFC WNDS CONTG N-NW OF ARCTIC CDFNT. LOOKING AT MDL QPF FCSTS AND UPWARD VERTICAL MOTION FIELDS IT APRS THAT THERE MAY BE A BATCH OF LGT FREEZING RAIN/SLEET MOVG THRU THE CWA DURING THE LT AFTN AND EVNG HRS. INCLUDED 5SM WITH -FZRAPL IN UIN AND COU...AND -FZRA IN STL AND SUS LT THIS AFTN AND THIS EVNG. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR CRAWFORD-IRON-MADISON- REYNOLDS-ST. FRANCOIS-STE. GENEVIEVE-WASHINGTON. ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR AUDRAIN-BOONE- CALLAWAY-COLE-CRAWFORD-FRANKLIN-GASCONADE-JEFFERSON-KNOX- LEWIS-LINCOLN-MARION-MONITEAU-MONROE-MONTGOMERY-OSAGE-PIKE- RALLS-SHELBY-ST. CHARLES-ST. LOUIS-ST. LOUIS CITY-WARREN- WASHINGTON. FREEZING RAIN ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR ST. FRANCOIS-STE. GENEVIEVE. IL...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR RANDOLPH IL-WASHINGTON IL. ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR ADAMS IL-BOND IL- BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-MONROE IL-MONTGOMERY IL-PIKE IL- ST. CLAIR IL. FREEZING RAIN ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR RANDOLPH IL-WASHINGTON IL. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1059 AM CST SAT JAN 13 2007 .UPDATE... CALLS MADE TO AREA OBSERVERS/SPOTTERS THIS MORNING INDICATE PRECIPITATION TYPE HAS BEEN PREDOMINATELY SLEET...MIXED WITH SNOW GENERALLY NORTHWEST OF THE TURNPIKE. ACCUMULATIONS HAVE GENERALLY BEEN AROUND 1/2 INCH...WITH ISOLATED 1 INCH AMOUNTS. DESPITE WARM WEDGE AROUND BETWEEN 900-700MB...ENOUGH COLD AIR IS PRESENT BELOW THE INVERSION TO REFREEZE THE RAIN DROPS INTO SLEET OVER SOUTHEAST KANSAS. MAY STILL GET A BIT OF FREEZING RAIN MIXED WITH THE SLEET OVER EXTREME SOUTHEAST KANSAS...BUT NOT ANTICIPATING MAJOR GLAZING ISSUES DUE TO FREEZING RAIN. BATCH OF PRECIPITATION CURRENTLY PUSHING ACROSS THE FORECAST AREA IS ASSOCIATED WITH A SUBTLE SHORTWAVE MOVING ACROSS WESTERN OKLAHOMA. THINKING THE MODERATE TO HEAVY SLEET WILL SLOWLY COME TO AN END FROM WEST TO EAST ACROSS THE FORECAST AREA AS THE AFTERNOON PROGRESSES...AS LIFT AHEAD OF THE SHORTWAVE PUSHES OFF TO THE EAST/NORTHEAST. HOWEVER...WILL LIKELY CONTINUE TO GET VERY LIGHT SLEET/SNOW DUE TO RESIDUAL WEAK LIFT AND COLD LOW-LEVEL TEMPERATURES. ANTICIPATING MAYBE ANOTHER 0.5-1.0 INCHES OF SLEET ACCUMULATION THIS AFTERNOON GENERALLY EAST OF THE TURNPIKE. SO FAR WINTER STORM WARNING CRITERIA HAS BEEN HARD TO COME BY. HOWEVER...FOR CONSISTENCY WILL ALLOW THE WINTER STORM WARNING TO CONTINUE UNTIL 6 PM SUNDAY AREAWIDE FOR THE TIME BEING. FOCUS THIS UPDATE HAS BEEN ON SHORT-TERM ISSUES. AN UPDATE ON THE SNOW POTENTIAL FOR TONIGHT AND SUNDAY WILL BE ISSUED AROUND 3-4 PM. KLEINSASSER && .PREV DISCUSSION... /ISSUED 720 AM CST SAT JAN 13 2007/ UPDATE... LATEST RADAR DATA SHOWS SOME IMPRESSIVE RETURNS OVER NORTHERN OKLAHOMA MOVING NORTHEAST INTO SOUTHERN KANSAS...MOST LIKELY AREAS OF VERY HEAVY SLEET. LOCAL 12Z RAB SOUNDINGS SUGGEST MAINLY SLEET FOR PRECIP TYPE ACROSS SOUTHERN KANSAS WITH A POSSIBLE CHANGE OVER TO SNOW LATER IN THE DAY. IR SATELLITE IMAGERY ACTUALLY SHOWED A FEW POCKETS OF WARMER TEMPS OVER CENTRAL AND SOUTH CENTRAL KANSAS EARLY THIS MORNING...THIS CREATED A VOID OF ICE CRYSTALS IN THE THERMAL PROFILE AND RESULTANT PRECIP WAS FREEZING DRIZZLE...HOWEVER WE EXPECT MORE SLEET AND SNOW DURING THE DAY AS COOLER CLOUD TOPS MOVE ACROSS THE REGION. SLEET ACCUMULATION IS LIKELY ACROSS SOUTHERN KANSAS WITH SOME LOCATIONS WITNESSING AN INCH OR MORE OF SLEET. MEANWHILE...A BUBBLE OF WARMER AIR ALOFT WAS PRESENT OVER CENTRAL OKLAHOMA EXTENDING NORTHWARD INTO SOUTHEAST KANSAS. THIS COULD YIELD ANOTHER EPISODE OF FREEZING RAIN ACROSS SOUTHEAST KANSAS. AS A RESULT...WE WILL INSERT A FREEZING RAIN/SLEET MIX FOR TODAY OVER THAT AREA. JAKUB PREV DISCUSSION... /ISSUED 508 AM CST SAT JAN 13 2007/ UPDATE... WE JUST SENT OUT A QUICK UPDATE TO INTRODUCE SLEET AND SNOW MIX THROUGH ABOUT 14Z. JUST MADE A COUPLE OF CALLS TO HARPER AND RUSSELL COUNTIES AND THEY ARE REPORTING SLEET THAT IS COVERING THE GROUND. THIS PRECIPITATION APPEARS TO BE ON THE LEADING EDGE OF THE WAVE MOVING ACROSS THE TEXAS PANHANDLE. LATEST IR SATELLITE LOOP IS SHOWING HIGHER TOPS MOVING ACROSS THAT REGION WHICH IS AN INDICATION OF MORE GROWTH IN THE DENDRITE REGION WHICH WOULD SUPPORT MORE IN THE WAY OF SNOW. AS A RESULT...IT STILL LOOKS LIKE WE COULD GET SOME DECENT SNOW LATE THIS MORNING INTO THE AFTERNOON. COX DISCUSSION... WE JUST SENT OUT A QUICK UPDATE TO INTRODUCE SLEET AND SNOW MIX THROUGH ABOUT 14Z. JUST MADE A COUPLE OF CALLS TO HARPER AND RUSSELL COUNTIES AND THEY ARE REPORTING SLEET THAT IS COVERING THE GROUND. THIS PRECIPITATION APPEARS TO BE ON THE LEADING EDGE OF THE WAVE MOVING ACROSS THE TEXAS PANHANDLE. LATEST IR SATELLITE LOOP IS SHOWING HIGHER TOPS MOVING ACROSS THAT REGION WHICH IS AN INDICATION OF MORE GROWTH IN THE DENDRITE REGION WHICH WOULD SUPPORT MORE IN THE WAY OF SNOW. AS A RESULT...IT STILL LOOKS LIKE WE COULD GET SOME DECENT SNOW LATE THIS MORNING INTO THE AFTERNOON. PREV DISCUSSION... /ISSUED 331 AM CST SAT JAN 13 2007/ DISCUSSION... THE MAIN CONCERN FOR TODAY THROUGH SUNDAY WILL BE PRECIPITATION TYPE AND HOW MUCH SNOW OR ICE WILL BE POSSIBLE DURING THE NEXT COUPLE OF DAYS. TODAY: LATEST IR LOOP AND SURFACE ANALYSIS SHOWING A FAIRLY STRONG WAVE MOVING THROUGH THE TEXAS PANHANDLE WITH EVEN SOME LIGHTNING STRIKES ASSOCIATED WITH IT. THIS WAVE WILL CONTINUE TO LIFT NORTHEAST THIS MORNING AND INCREASE THE ISENTROPIC ASCENT MARKEDLY ACROSS THE FORECAST AREA TODAY. THE 00Z GFS/RUC SEEM TO HANDLE THE STRENGTH OF THIS WAVE BASED ON THE IR AND WATER VAPOR LOOPS. AS A RESULT...WE ARE FAVORING THESE SOLUTIONS FOR THE POTENTIAL FOR SOME DECENT SNOW AND SLEET ACCUMULATIONS TODAY. WE ARE MAKING SOME ADJUSTMENTS TO THE PRECIPITATION TYPE OVER THE ENTIRE AREA SINCE IT APPEARS LIKE MOST OF BOUNDARY LAYER TEMPERATURES AROUND -10 DEG C WHICH IS SUPPORTIVE OF PRECIPITATION REFREEZING BEFORE IT REACHES THE GROUND. THEREFORE...WE ARE LOOKING AT MORE OF A SNOW OR SLEET POTENTIAL ACROSS SOUTHEAST KANSAS TODAY. THE MAIN CONCERN RIGHT NOW...IS SOUTH CENTRAL KANSAS WHERE THEY COULD SEE MORE IN THE WAY OF SNOW WITH ACCUMULATIONS UP TO 4 INCHES BY LATE AFTERNOON. THE GFS DOES SHOW SOME COOLING AROUND 700MB DUE TO LATENT HEAT PROCESS...BUT WE BELIEVE IT MAY NOT BE COOLING THAT COLUMN ENOUGH DUE TO SUCH STRONG LIFT IN THAT REGION. THE COBB TECHNIQUE IS ALSO SUPPORTIVE OF THIS. MEANWHILE...FOLKS IN CENTRAL KANSAS COULD SEE AT LEAST 2 INCHES OF SNOW. WE WENT AHEAD AND UPGRADED THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING AND CONTINUED IT THROUGH SUNDAY SINCE WE ARE ANTICIPATING THIS WHOLE EVENT TO PRODUCE 6 INCHES OF SNOW OR MORE OVER MOST OF CENTRAL AND SOUTH CENTRAL KANSAS. THE WINTER STORM WARNING STILL LOOKS GOOD FOR THE REMAINDER OF THE AREA SINCE THE SLEET AND SNOW ACCUMULATIONS WILL BE SIGNIFICANT. TONIGHT-SUNDAY: THE MODELS ARE ADVERTISING ANOTHER BREAK IN THE PRECIPITATION THIS EVENING...BEFORE THE MAIN UPPER TROF MOVES INTO THE WESTERN SECTIONS OF OUR FORECAST AREA OVERNIGHT. THIS TROF SHOULD BRING ANOTHER ROUND OF SNOW AND SLEET TO THE AREA WITH THE BEST CHANCE OF SNOW ACROSS CENTRAL AND SOUTH CENTRAL KANSAS WHERE ANOTHER 2 TO 5 INCHES OF SNOW WILL BE POSSIBLE BY SUNDAY EVENING WITH THE HIGHEST AMOUNTS EXPECTED TO BE IN CENTRAL KANSAS WHERE THEY WILL BE CLOSEST TO THE MID LEVEL BAROCLINIC ZONE. THERE WILL ALSO BE SOME AID FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET WHICH WILL INCREASE THE ISENTROPIC ASCENT WITH ADDITIONAL LIFT FROM MID LEVEL FRONTOGENETICAL CIRCULATIONS. WE MAY END UP INCREASING SNOW AMOUNTS EVEN MORE IN LATER FORECASTS. SUNDAY NIGHT-WEDNESDAY: WE SHOULD BEGIN TO SEE THE SNOW MOVING OUT OF THE PICTURE SUNDAY NIGHT. THEN THE ARCTIC HIGH WILL BEGIN TO SETTLE OVER US DURING THE NEXT COUPLE OF DAYS. WE LOWERED HIGHS AND LOWS SEVERAL DEGREES ESPECIALLY ON MONDAY AND TUESDAY WHERE THE SURFACE RIDGE BEGINS TO PARK OVER THE AREA. WITH LOTS OF SNOW COVER AND NORTHERLY FLOW OVER US...WE WILL BE HARD PRESSED TO MAKE INTO THE 20S WITH LOWS POSSIBLY DROPPING BELOW ZERO. COX && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 17 12 19 10 / 100 70 100 40 HUTCHINSON 15 10 17 8 / 100 70 100 40 NEWTON 16 11 18 9 / 100 50 100 40 ELDORADO 17 12 18 10 / 100 50 100 40 WINFIELD-KWLD 19 14 19 12 / 100 70 100 30 RUSSELL 13 8 14 5 / 100 70 100 50 GREAT BEND 13 8 16 6 / 100 80 100 50 SALINA 14 9 17 7 / 100 40 100 50 MCPHERSON 15 9 17 7 / 100 50 100 40 COFFEYVILLE 23 17 23 16 / 100 60 100 30 CHANUTE 21 16 21 14 / 100 60 100 40 IOLA 21 15 21 13 / 100 60 100 40 PARSONS-KPPF 22 17 22 15 / 100 60 100 30 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM CST SUNDAY FOR KSZ032-033- 047>053-067>072-082-083-091>096-098>100. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 403 PM CST SAT JAN 13 2007 .DISCUSSION... LOCALLY HEAVY RAINFALL CONTINUES ACROSS THE NORTHERN HALF OF NORTHEAST TEXAS...SOUTHEAST OKLAHOMA AND SOUTHWEST ARKANSAS THIS AFTERNOON AND NOT EXPECTING THIS TO CHANGE MUCH ANY TIME SOON. FLASH FLOOD WATCHES WERE POSTED EARLY THIS MORNING FOR THIS REGION AND THE ONLY ADJUSTMENT WAS TO EXTEND THE WATCH INTO SUNDAY EVENING AS THE HEAVY RAIN SHOULD BE COMING TO AND END SUNDAY NIGHT. THIS LARGE AREA OF PRECIPITATION WILL EVENTUALLY BEGIN TO FILL IN FURTHER SOUTH AND EAST THUS HAVE KEPT POPS RATHER HIGH ACROSS NORTHWEST LOUISIANA BUT HAVE TRIMED POPS BACK TO CHANCE TONIGHT AND SUNDAY ACROSS OUR EXTREME EASTERN PARISHES. COLD FRONT HAS SLOWED TO A CRAWL TODAY...NOW LOCATED NEAR A HOT SPRINGS...TEXARKANA...MARSHALL...MOUNT ENTERPRISE LINE. HAVE FOLLOWED THE RUC FCST CLOSELY OVER THE NEXT 12HRS WHICH ONLY BRINGS THE FRONT A LITTLE FURTHER EAST OVERNIGHT...INTO THE SHREVEPORT/BOSSIER CITY AREA NEAR OR SHORTLY AFTER MIDNIGHT. THIS FRONT WILL AGAIN PULL UP NEARLY STATIONARY DURING THE DAY SUNDAY AS A SECONDARY SHOT OF COLD ARCTIC AREA DIVES DOWN OUT OF SOUTHERN OKLAHOMA AND NORTH TEXAS WHICH PROMISES TO KICK THE ORIGIONAL BOUNDARY THROUGH ALL OF THE REGION BY LATE SUNDAY NIGHT INTO EARLY MONDAY. MEDIUM RANGE PROGS REMAIN UNCERTAIN AT THIS TIME CONCERNING THE DEGREE OF OVERRUNNING MOISTURE SUNDAY NIGHT INTO MONDAY BUT THE NAM PROG...WHICH OF LATE HAS BEEN FAR SUPERIOR TO THE GFS...PUSHES THE 32 DEGREE ISOTHERM INTO A GOOD PORTION OF NORTHEAST TEXAS...SOUTHEAST OKLAHOMA AND SOUTHWEST ARKANSAS BEGINNING LATE SUNDAY NIGHT THROUGH AT LEAST THE FIRST HALF OF THE DAY MONDAY. FOR THIS REASON...HAVE POSTED A WINTER STORM WATCH FOR SUNDAY NIGHT AND MONDAY ALONG AND NORTH OF A LINE FROM JACKSONVILLE AND TEXARKANA TEXAS TO LEWISVILLE AND PRESCOTT ARKANSAS. AT THIS TIME...IT DOES NOT APPEAR THAT FREEZING RAINFALL AMOUNTS WILL BE EXCESSIVE BUT THE WATCH IS A GOOD START THIS FAR IN ADVANCE SUCH THAT IF IT APPEARS LIKE CONDITIONS WARRANT...THE WATCH CAN BE EXPANDED OR UPGRADED TO AN ADVISORY OR WARNING ISSUED BY LATER SHIFTS. FOR THE EXTENDED PACKAGE...TROUGH CONTINUES TO RELOAD ACROSS THE SOUTHWEST CONUS AND THUS WE REMAIN IN A MOIST SOUTHWEST FLOW REGIME THROUGH THE WEEK AND INTO NEXT WEEKEND. HAVE INTRODUCED SLIGHT CHANCE POPS THROUGH MUCH OF THE UPCOMING WEEK AND BETTER CHANCES FOR THUNDERSTORMS BY LATE NEXT WEEK/ NEXT WEEKEND WITH THE APPROACH OF ANOTHER COLD FRONT. 13 && .AVIATION... IFR/LIFR CIGS WILL CONTINUE UNDER THE RAIN AREA ALONG/BEHIND THE COLD FRONT...WHICH HAS NOW SHIFTED JUST E OF TXK...TO N CADDO PARISH...TO JUST E OF MARSHALL...TO DKR AS OF 21Z. EMBEDDED THUNDER CONTINUES AS WELL...ALTHOUGH THESE CAN BE HANDLED IN TEMPO GROUPS IN THE 00Z TAF ISSUANCE. CIGS HAVE BECOME VFR FARTHER E ACROSS DEEP E TX AND MUCH OF N LA...ALTHOUGH THIS WILL NOT LAST LONG AS MVFR/IFR STRATUS DEVELOPS TONIGHT. ADDITIONAL RAINFALL REDEVELOPMENT WILL OCCUR FARTHER E INTO SW AR/NW LA/DEEP E TX...INCLUDING THE ELD/SHV/LFK TERMINALS...THUS WILL PREVAIL MVFR/IFR CIGS/VSBYS AT THESE LOCATIONS TONIGHT. RAINFALL WILL REMAIN PERSISTENT OVER ALL BUT THE MLU TERMINAL THROUGHOUT MUCH OF THE TAF PERIOD. FROZEN PCP WILL REMAIN ACROSS E/S OK AND N TX THROUGH 00Z MONDAY...BEFORE RAIN BEGINS TO CHANGE OVER TO -FZRA OVER MCCURTAIN CO. OK/DEQ PRIOR TO 6Z. /15/ && .PRELIMINARY POINT TEMPS/POPS... SHV 56 58 37 40 / 80 90 100 70 MLU 65 74 48 48 / 50 50 100 70 DEQ 40 40 31 38 / 100 100 100 50 TXK 48 50 32 38 / 100 100 100 50 ELD 57 64 39 41 / 80 100 100 70 TYR 39 40 31 38 / 100 100 100 50 GGG 47 47 32 39 / 100 100 100 50 LFK 58 64 37 40 / 80 90 100 70 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH UNTIL 9 PM SUNDAY FOR THE FOLLOWING ZONES: HEMPSTEAD...HOWARD...LAFAYETTE...LITTLE RIVER...MILLER...NEVADA...AND SEVIER. WINTER STORM WATCH FROM 9 PM SUNDAY TO NOON MONDAY FOR THE FOLLOWING ZONES: HEMPSTEAD...HOWARD...LAFAYETTE...LITTLE RIVER...MILLER...NEVADA...AND SEVIER. LA...NONE. OK...FLASH FLOOD WATCH UNTIL 9 PM SUNDAY FOR THE FOLLOWING ZONES: AND MCCURTAIN. WINTER STORM WATCH FROM 9 PM SUNDAY TO NOON MONDAY FOR THE FOLLOWING ZONES: AND MCCURTAIN. TX...FLASH FLOOD WATCH UNTIL 9 PM SUNDAY FOR THE FOLLOWING ZONES: BOWIE...CAMP...CASS...CHEROKEE...FRANKLIN...GREGG...HARRISON... MARION...MORRIS...RED RIVER...RUSK...SMITH...TITUS...UPSHUR... AND WOOD. WINTER STORM WATCH FROM 9 PM SUNDAY TO NOON MONDAY FOR THE FOLLOWING ZONES: BOWIE...CAMP...CASS...CHEROKEE...FRANKLIN...GREGG...HARRISON... MARION...MORRIS...PANOLA...RED RIVER...RUSK...SMITH...TITUS... UPSHUR...AND WOOD. && $$ 13/15 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 1050 AM CST SAT JAN 13 2007 .UPDATE... SECOND WAVE OF WINTRY PRECIP TO ARRIVE THIS AFTERNOON AS REGIONAL RADAR SHOWS IMPRESSIVE PRECIPITATION DEVELOPMENT TO THE SOUTHWEST. NORTHWEST COUNTIES SHOULD SEE A SLEET/FZRA MIX WITH UP TO AN ADDITIONAL INCH OF SLEET ACCUMULATION...WHILE THE REMAINDER OF THE ADVISED AND WARNED AREA SEES FREEZING RAIN...WITH BETWEEN A TENTH AND A QUARTER OF AN INCH OF ADDITIONAL ICE ACCUMULATION. OVER A 100,000 PEOPLE ARE NOW WITHOUT POWER ACCORDING TO AMEREN ELECTRIC COMPANY. CVKING && .DISCUSSION... ...ICE STORM WARNING CONTINUES ACROSS MUCH OF THE REGION THROUGH SUNDAY NIGHT... THE FIRST WAVE OF THE STORM HAS PRODUCED A PRETTY GOOD HIT ON THE AREA. IF THERE IS ANY SAVING GRACE IT IS THAT A GOOD DEAL OF THE PCPN ACRS NE MO/WEST CENTRAL IL INTO CENTRAL MO HAS BEEN IN THE FORM OF SLEET AND THIS HAS REDUCED THE AMOUNT OF ICE GLAZE FROM FREEZING RAIN. SLEET HAS BEEN REPORTED AS FAR EAST AS TROY AND WARRENTON. OUR BEST ESTIMATE FROM SPOTTER REPORTS IS THE ZR ICE GLAZE RANGES FROM AROUND ONE-QUARTER INCH FROM WESTERN ST LOUIS METRO UPWARDS TO A HALF-INCH HEADING TOWARDS COLUMBIA. WE ARE GETTING REPORTS OF DOWNED TREES AND POWER LINES AND ASSOCIATED POWER OUTAGES WITHIN THIS CORRIDOR. THE CURRENT SOLID WAVE OF PCPN IS SHOWING A DECIDED BACK EDGE...RUNNING THRU NE AND CNTRL MO. THIS WAVE OF PCPN SHOULD CONT TO SHIFT EAST THIS MORNING...AND BELIEVE IT WILL EXIT MOST OF THE REGION WITH MAYBE THE EXCEPTION OF FAR SE MO AND SRN IL BY MID MORNING. WEAK LOW LEVEL CAA IS CONTINUING WITH THE NNWLY WINDS ACROSS THE REGION... AND KFAM IS NOW DOWN TO FREEZING. AS A RESULT HAVE ISSUED A FREEZING RAIN ADVISORY TODAY FOR THE REGION FROM FARMINGTON TO SPARTA TO NASHVILLE. ADDITIONAL ICE GLAZE THIS MORNING EXPECTED TO REMAIN LESS THAN A QUARTER INCH OVER PORTIONS OF ECNTRL MO INTO SW IL. AFTER THIS MAIN BATCH OF PCPN EXITS EAST...THINK WE WILL ONLY SEE PERIODIC BATCHES OF LIGHT PCPN SKIRT ACROSS THE AREA...NOTHING LIKE THE INTENSITY WE HAVE SEEN THE LAST 18H OR SO. THIS SHOULD CONTRIBUTE NO MORE THAN A LIGHT ICE GLAZE. EXPECTING PCPN TNGT WILL ALSO BE RELATIVELY LIGHT WITHIN THE COLD AIR...WITH THE HEAVIEST PCPN HAVING SHIFTED S AND SE OF THE CWFA. ONCE AGAIN ANY ADDITIONAL ICE GLAZE TONIGHT WILL BE LIGHT. THE FINAL ROUND OF PCPN ASSOCIATED WITH THIS PROLONGED EVENT WILL IMPACT THE REGION ON SUNDAY AS STRONG LARGE SCALE ASCENT OVERSPREADS THE REGION IN ASSOCIATION WITH THE EJECTING MID-UPR LEVEL TROF. THIS ROUND OF THE STORM SHOULD BE AS BAD OR WORSE THAN THIS FIRST WAVE WE HAVE BEEN EXPERIENCING WITH WDSPRD PCPN AMOUNTS OF AT LEAST ONE- HALF INCH. MODEL SOUNDINGS AND P-TYPE ALGORITHMS SHOW THE MAJORITY OF THE PCPN FROM CENTRAL MO INTO WEST CENTRAL IL SHOULD BE IN THE FORM OF SLEET. SIGNIFICANT ICING FROM FREEZING RAIN LIKELY IN MUCH THE SAME LOCATION WE HAVE JUST EXPERIENCED...NAMELY ST LOUIS METRO TO ABOUT 50 MILES WEST. ADDITIONAL ICE ACCUMS OF AROUND ONE-HALF INCH APPEAR QUITE REASONABLE GIVEN QPF IN THE .50-.75 RANGE. THIS ADDITIONAL ICE ACCUMULATION ALONG WITH GUSTY NW WINDS LATE SUNDAY NIGHT AND MONDAY COULD BE DEVASTATING GIVEN OUR CURRENT SITUATION WITH ICE ALREADY WEIGHING HEAVILY ON TREES AND POWER LINES. THE POTENTIAL FOR WIDESPREAD POWER OUTAGES ACROSS EASTERN MO INTO WESTERN ILLINOIS IS VERY REAL. ACROSS NE MO INTO WEST CENTRAL ILLINOIS THE COLD AIR SHOULD DEEPEN ENUF BY SUNDAY EVENING FOR A BAND OF 2-3 INCHES OF SNOW. FINALLY...THE RAIN HAS BEGUN TO IMPACT SOME OF THE RIVERS AND STREAMS ACROSS SRN MO. WE HAVE SOME REPORTS OF THE TYPICAL FLOODED LOW WATER CROSSINGS AND THE RIVERS SHOULD BEGIN TO RESPOND TODAY. THUS THE FLOOD WATCH STILL LOOKS QUITE GOOD IN THIS AREA. A SIDE NOTE - THE NORMAL MODEL GUIDANCE SUITE OF THE GFS AND NAM CONTINUES TO HAVE PROBLEMS WITH THE INTENSITY AND EXTENT OF THE COLD AIR. THE OPERATIONAL RUC AND DEVELOPMENTAL RUC THROUGH 48H APPEAR TO HAVE THE BEST HANDLE ON THE SURFACE TEMPERATURE PROFILE. GLASS && .AVIATION... FOR THE 18Z TAFS... IFR CONDITIONS TO CONTINUE THROUGH TAF PERIOD WITH A PERIOD OF FREEZING RAIN AND SLEET EXPECTED TO BEGIN THIS AFTERNOON AND CONTINUE INTO THIS EVENING. WINDS WILL REMAIN OUT OF THE NORTH BETWEEN 5 AND 10 KTS. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR CRAWFORD-IRON-MADISON- REYNOLDS-ST. FRANCOIS-STE. GENEVIEVE-WASHINGTON. ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR AUDRAIN-BOONE- CALLAWAY-COLE-CRAWFORD-FRANKLIN-GASCONADE-JEFFERSON-KNOX- LEWIS-LINCOLN-MARION-MONITEAU-MONROE-MONTGOMERY-OSAGE-PIKE- RALLS-SHELBY-ST. CHARLES-ST. LOUIS-ST. LOUIS CITY-WARREN- WASHINGTON. FREEZING RAIN ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR ST. FRANCOIS-STE. GENEVIEVE. IL...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR RANDOLPH IL-WASHINGTON IL. ICE STORM WARNING UNTIL 6 AM CST MONDAY FOR ADAMS IL-BOND IL- BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-MONROE IL-MONTGOMERY IL-PIKE IL- ST. CLAIR IL. FREEZING RAIN ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR RANDOLPH IL-WASHINGTON IL. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1244 PM EST SAT JAN 13 2007 .AVIATION /18Z-18Z/... THE MORE CONCENTRATED AREA OF RAINFALL HAS REALIGNED ITSELF ALONG AND SOUTH OF THE FRNTL BNDRY POSN EXTNDG FROM NEAR KCVG TO KILN TO KLHQ. NORTH OF THE BNDRY...-RA AND/OR -DZ WAS BEING REPORTED. THE BNDRY WILL CONTINUE TO DROP SOUTH THIS AFTN...EVENTUALLY STALLING OUT SOMEWHERE FAIRLY CLOSE TO THE OHIO RIVER. THIS WILL MAKE THE WIND DIR SOMEWHAT PROBLEMATIC FOR ALL TAFS BUT KDAY OVERNIGHT DUE TO RELATIVE PROXIMITY OF BNDRY. HAVE LEFT -RA IN TAFS THIS AFTN WITH THE BULK OF THE PCPN SETTLING SOUTH OF THE TAFS IN NRN KY BY 00Z IN ACCORDANCE WITH THE FRNTL BNDRY. MODEL SOUNDINGS THIS EVNG DO SUPPORT SOME -DZ POTENTIAL...AND HAVE INCLUDED IN TEMPOS AT KCMH/KLCK/KDAY/KILN. ANOTHER WAVE OF LO PRES CURRENTLY IN ARKANSAS WILL LIFT NORTH ALONG FRNTL BNDRY AND MOVE INTO THE REGION TOWARDS DAYBREAK SUN. THIS WILL KEEP THE BREAK FROM MORE SUBSTANTIAL PCPN FAIRLY SHORTLIVED THIS EVNG...WITH WIDESPREAD PCPN COVERAGE AFFECTING ALL TAFS BTWN 06-10Z AND CONTINUING THRU THE REMAINDER OF THE FCST PERIOD. VSBYS MAY IMPROVE SOME THIS AFTN...OSCILLATING BTWN IFR AND VFR. AFT DARK...PREDOMINANT MVFR VSBYS ARE EXPECTED WITH IFR VSBYS WITH HEVAIER RAIN LATE TONIGHT INTO SUN. WITH STRONG INVERSION NOTED ON MODEL SOUNDINGS AT AROUND 1000 FT AGL...EXPECT CIGS TO REMAIN AT IFR AND LOWER THRU FCST PERIOD. RYAN && .PREV DISCUSSION... /ISSUED 1140 AM EST SAT JAN 13 2007/ SHORT TERM /THIS AFTERNOON/... FRNTL BNDRY SLOWLY DROPPING SOUTH THIS MRNG...AND IS NOW LOCATED FROM SRN INDIANA NE THRU NRN CINCY SUBURBS...TO JUST NORTH OF KILN CONTINUING NE INTO NRN FAIRFIELD CO JUST SOUTH OF CMH METRO. PCPN COVERAGE AND INTENSITY HAS DIMINISHED AS FIRST SFC WAVE HAS MOVED WELL TO EAST INTO CNTRL PA...AND AXIS OF BNDRY LYR FORCING ALONG 850 LLJ HAS SHIFTED SOUTH TO NEAR THE OHIO RIVER. HEAVIEST RAIN SO FAR HAS FALLEN FROM THE WHITEWATER VLY EAST INTO THE SRN DAYTON METRO AREA IN GREENE AND NRN WARREN COS WITH 1.25-1.5 INCHES...THE BULK OF WHICH HAS OCCURRED SINCE LAST EVNG. A SOLID 0.75 TO 1 INCH HAS FALLEN ELSEWHERE ACRS NRN FCST AREA...WITH LIGHTER AMOUNTS NEAR AND SOUTH OF THE OHIO RIVER. FCST UPDATE MAINLY TO FOCUS ON PCPN COVERAGE AND TEMP PROFILES FOR AFTN. 12Z NAM/RUC BOTH HAVE A NICE HANDLE ON CURRENT FRNTL BNDRY POSN. FRONT WILL CONTINUE TO SLIDE SOUTH THIS AFTN...EVENTUALLY STALLING OUT SOMEWHERE ACRS SRN PORTIONS OF FCST AREA THIS EVNG. LOWERED POPS FASTER ALONG AND NORTH OF I-70 THIS AFTN AS THIS AREA SHOULD SEE A SVRL HOUR BREAK FROM HEAVIER PCPN. MODEL SOUNDINGS AND CURRENT OBS THOUGH DO SUPPORT POTENTIAL FOR -SHRA AND/OR -DZ THRU AFTN HOURS. CAT POPS WILL CONTINUE ACRS SRN 1/2 FCST AREA INTO TONIGHT AS BNDRY STALLS AND NEXT SFC WAVE OVER SW ARKANSAS LIFTS NE ALONG BNDRY. HAVE INDICATED STEADY OR FALLING TEMPS JUST ABOUT EVERYWHERE THIS AFTN AS TEMPS ARE AND WILL CONTINUE TO TUMBLE WITH FROPA. THIS FORCED A CHANGE IN TEMPS TONIGHT AS EVENING LOWS ARE EXPECTED WITH SFC WAVE APPCHG FROM THE SW. THIS SHOULD ALLOW TEMPS TO REMAIN STEADY...OR BEGIN TO RISE LATER IN THE OVERNIGHT. FCST UPDATE OUT...PREV DISCUSSION FOLLOWS. RYAN PREV DISCUSSION... /ISSUED 412 AM EST SAT JAN 13 2007/ SHORT TERM /TODAY THROUGH MONDAY/... CDFNT IS NOW INTO THE EXTREME NW COUNTIES RUNNING FROM NR FDY- AOH-MIE ATTM. CDFNT WILL SLOWLY DROP THRU THE FA AREA TODAY...PUSHING AXIS OF HEAVY RAINS SOUTHWARD TOWARDS SRN OH/NRN KY. THE NRN COUNTIES WILL SEE A DRYING TREND DURING THE AFTN. BY 00Z SUN THE FRONT WILL STRETCH FROM NE TN INTO CNTRL WV. 40 KT H8 JET WILL HELP ENHANCE PCPN ACROSS THE SOUTH TONIGHT. MODELS BEGIN TO DIFFER TONIGHT. NAM PUSHES A LOW ACROSS THE REGION...WHILE THE GFS JUST ENHANCES AN INVERTED TROF. EITHER WAY CATEGORICAL POPS CAN BE EXPECTED. BOTH MODELS HAVE INCREASED THE WARMTH OF THE ATMOSPHERE...SO DONT EXPECT ANY FREEZING/FROZEN PCPN ON THE NORTHERN EDGE. ON SUNDAY...ADDITIONAL ISENTROPIC LIFT IS PROVIDED AS LOW PRESSURE WAVES RUN ALONG THE FRONT...WHICH HAS WORKED BACK NORTH INTO THE REGION. GFS AND NAM DIVERGE ONCE AGAIN LATE SUNDAY NIGHT INTO MONDAY. THE GFS PUSHES A WEAKER LOW INTO WV BY 12Z...WHILE THE NAM WINDS UP A LOW AND PULLS IT NORTH ALONG THE OHIO/INDIANA BORDER. PREFER THE GFS SOLUTION...THEREFORE WILL MIX A LITTLE SLEET ON THE BACKSIDE BEFORE THE RAIN CHANGES TO SNOW AS THE COLDER AIR WORDS IN. THE THREAT OF A HEAVY FREEZING RAIN/SLEET EVENT HAS DIMINISHED WITH THIS RUN. WE WILL SEE IF THE MODELS CONTINUE WITH THIS TREND. AS FOR TEMPS. IT WAS TRICKY TODAY...TRYING TO FIGURE WHERE THE CDFNT WOULD BE AT 12Z. IS APPEARS THAT THE FNT IS A LITTLE FARTHER NORTH THAN THE MODELS THOUGHT AT 06Z...SO WENT WITH A WARMER TEMPS THAN THE GFS MOS WAS GIVING...ESPECIALLY IN THE NORTH. WENT CLOSER TO THE ETA MOS. WENT A BLEND OF THE ETA/GFS MOS FOR TONIGHT...THEN WENT CLOSE TO GFS MOS FOR PERIODS 3 THRU 5. SITES LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... SLOWED THE CHANGE OVER TO SNOW IN THE E/SE MONDAY NIGHT BY STARTING OFF WITH EITHER A MIX OR ALL RAIN. ALSO PUSHED LOW TEMPS MONDAY NIGHT UP A COUPLE OF DEGREES. SITES && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH THROUGH MONDAY MORNING FOR OHZ053>055-060>065-070>074- 077>082-088. KY...FLOOD WATCH THROUGH MONDAY MORNING FOR KYZ089>100. IN...FLOOD WATCH THROUGH MONDAY MORNING FOR INZ050-058-059-066-073>075- 080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1140 AM EST SAT JAN 13 2007 .SHORT TERM /THIS AFTERNOON/... FRNTL BNDRY SLOWLY DROPPING SOUTH THIS MRNG...AND IS NOW LOCATED FROM SRN INDIANA NE THRU NRN CINCY SUBURBS...TO JUST NORTH OF KILN CONTINUING NE INTO NRN FAIRFIELD CO JUST SOUTH OF CMH METRO. PCPN COVERAGE AND INTENSITY HAS DIMINISHED AS FIRST SFC WAVE HAS MOVED WELL TO EAST INTO CNTRL PA...AND AXIS OF BNDRY LYR FORCING ALONG 850 LLJ HAS SHIFTED SOUTH TO NEAR THE OHIO RIVER. HEAVIEST RAIN SO FAR HAS FALLEN FROM THE WHITEWATER VLY EAST INTO THE SRN DAYTON METRO AREA IN GREENE AND NRN WARREN COS WITH 1.25-1.5 INCHES...THE BULK OF WHICH HAS OCCURRED SINCE LAST EVNG. A SOLID 0.75 TO 1 INCH HAS FALLEN ELSEWHERE ACRS NRN FCST AREA...WITH LIGHTER AMOUNTS NEAR AND SOUTH OF THE OHIO RIVER. FCST UPDATE MAINLY TO FOCUS ON PCPN COVERAGE AND TEMP PROFILES FOR AFTN. 12Z NAM/RUC BOTH HAVE A NICE HANDLE ON CURRENT FRNTL BNDRY POSN. FRONT WILL CONTINUE TO SLIDE SOUTH THIS AFTN...EVENTUALLY STALLING OUT SOMEWHERE ACRS SRN PORTIONS OF FCST AREA THIS EVNG. LOWERED POPS FASTER ALONG AND NORTH OF I-70 THIS AFTN AS THIS AREA SHOULD SEE A SVRL HOUR BREAK FROM HEAVIER PCPN. MODEL SOUNDINGS AND CURRENT OBS THOUGH DO SUPPORT POTENTIAL FOR -SHRA AND/OR -DZ THRU AFTN HOURS. CAT POPS WILL CONTINUE ACRS SRN 1/2 FCST AREA INTO TONIGHT AS BNDRY STALLS AND NEXT SFC WAVE OVER SW ARKANSAS LIFTS NE ALONG BNDRY. HAVE INDICATED STEADY OR FALLING TEMPS JUST ABOUT EVERYWHERE THIS AFTN AS TEMPS ARE AND WILL CONTINUE TO TUMBLE WITH FROPA. THIS FORCED A CHANGE IN TEMPS TONIGHT AS EVENING LOWS ARE EXPECTED WITH SFC WAVE APPCHG FROM THE SW. THIS SHOULD ALLOW TEMPS TO REMAIN STEADY...OR BEGIN TO RISE LATER IN THE OVERNIGHT. FCST UPDATE OUT...PREV DISCUSSION FOLLOWS. RYAN && .PREV DISCUSSION... /ISSUED 642 AM EST SAT JAN 13 2007/ AVIATION /12Z-12Z/... FCST IS NOT CHANGING MUCH FOR THE NEXT 24 HOURS. PROXIMITY OF THE FRONT WILL KEEP CIGS AOB 1KFT FOR THE MOST PART ACROSS THE BOARD. ONE OR TWO SITES WILL POP OUT OF THE LOW STUFF FROM TIME TO TIME...BUT THIS WILL BE THE EXCEPTION VERSUS THE RULE FOR THIS SET OF TAFS. HAVE TRIED TO LOWER THE CHANCES FOR RAIN LATER THIS AFTERNOON AND EVENING FOR MUCH OF THE REGION AS THE PRECIP SHOULD TURN OFF FROM NW-SE. HOWEVER...COULDN`T IN GOOD CONSCIENCE GO ENTIRELY DRY SO I ADDED A FEW HOURS OF DZ UNDERNEATH THE CONTINUED LOW CIGS. ANOTHER WAVE WILL THEN APPROACH THE REGION FROM THE SOUTHWEST OVERNIGHT...SPREADING MORE CATEGORICAL POPS FROM SW-NE AFTER ABOUT 6Z. FRANKS SHORT TERM /TODAY THROUGH MONDAY/... CDFNT IS NOW INTO THE EXTREME NW COUNTIES RUNNING FROM NR FDY- AOH-MIE ATTM. CDFNT WILL SLOWLY DROP THRU THE FA AREA TODAY...PUSHING AXIS OF HEAVY RAINS SOUTHWARD TOWARDS SRN OH/NRN KY. THE NRN COUNTIES WILL SEE A DRYING TREND DURING THE AFTN. BY 00Z SUN THE FRONT WILL STRETCH FROM NE TN INTO CNTRL WV. 40 KT H8 JET WILL HELP ENHANCE PCPN ACROSS THE SOUTH TONIGHT. MODELS BEGIN TO DIFFER TONIGHT. NAM PUSHES A LOW ACROSS THE REGION...WHILE THE GFS JUST ENHANCES AN INVERTED TROF. EITHER WAY CATEGORICAL POPS CAN BE EXPECTED. BOTH MODELS HAVE INCREASED THE WARMTH OF THE ATMOSPHERE...SO DONT EXPECT ANY FREEZING/FROZEN PCPN ON THE NORTHERN EDGE. ON SUNDAY...ADDITIONAL ISENTROPIC LIFT IS PROVIDED AS LOW PRESSURE WAVES RUN ALONG THE FRONT...WHICH HAS WORKED BACK NORTH INTO THE REGION. GFS AND NAM DIVERGE ONCE AGAIN LATE SUNDAY NIGHT INTO MONDAY. THE GFS PUSHES A WEAKER LOW INTO WV BY 12Z...WHILE THE NAM WINDS UP A LOW AND PULLS IT NORTH ALONG THE OHIO/INDIANA BORDER. PREFER THE GFS SOLUTION...THEREFORE WILL MIX A LITTLE SLEET ON THE BACKSIDE BEFORE THE RAIN CHANGES TO SNOW AS THE COLDER AIR WORDS IN. THE THREAT OF A HEAVY FREEZING RAIN/SLEET EVENT HAS DIMINISHED WITH THIS RUN. WE WILL SEE IF THE MODELS CONTINUE WITH THIS TREND. AS FOR TEMPS. IT WAS TRICKY TODAY...TRYING TO FIGURE WHERE THE CDFNT WOULD BE AT 12Z. IS APPEARS THAT THE FNT IS A LITTLE FARTHER NORTH THAN THE MODELS THOUGHT AT 06Z...SO WENT WITH A WARMER TEMPS THAN THE GFS MOS WAS GIVING...ESPECIALLY IN THE NORTH. WENT CLOSER TO THE ETA MOS. WENT A BLEND OF THE ETA/GFS MOS FOR TONIGHT...THEN WENT CLOSE TO GFS MOS FOR PERIODS 3 THRU 5. SITES LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... SLOWED THE CHANGE OVER TO SNOW IN THE E/SE MONDAY NIGHT BY STARTING OFF WITH EITHER A MIX OR ALL RAIN. ALSO PUSHED LOW TEMPS MONDAY NIGHT UP A COUPLE OF DEGREES. SITES && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLOOD WATCH THROUGH MONDAY MORNING FOR OHZ053>055-060>065- 070>074-077>082-088. KY...FLOOD WATCH THROUGH MONDAY MORNING FOR KYZ089>100. IN...FLOOD WATCH THROUGH MONDAY MORNING FOR INZ050-058-059-066- 073>075-080. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 1148 AM CST SAT JAN 13 2007 .UPDATE... UPDATED FORECAST TO INCLUDE CHANCE OF LIGHT SNOW OVER MAINLY WESTERN HALF OF CWA. RUC SEEMS TO HAVE BEST HANDLE ON THE ONGOING PRECIP /LIGHT SNOW/ OVER IA ATTM...AND BRINGS BRIEF PERIOD OF LIFT AND DEEP SATURATION ACROSS THE CWA DURING THE AFTERNOON. QPF AMOUNTS SHOULD BE LIGHT...WITH RUC GENERATING A COUPLE HUNDREDTHS...HOWEVER WITH VSBYS UPSTEAM DROPPING AROUND 1SM AT TIMES...COULD SEE UP TO HALF INCH OF SNOW. MAY NEED TO EVENTUALLY DRAG SNOW CHANCES FURTHER EAST...BUT WILL HOLD OFF FOR TIME BEING. ALSO WATCHING THE POTENTIAL FOR A FEW LAKE EFFECT SNOW SHOWERS FM LAKE MICHIGAN...WITH MILWAUKEE TERMINAL DOPPLER RADAR INDICATING A VERY WEAK BAND TRYING TO FORM ATTM. WITH RETURNS GNRLLY AOB 15DBZ...WILL CONTINUE TO KEEP MENTION OF A FEW FLURRIES. MAF && .PREV DISCUSSION... /ISSUED 257 AM CST SAT JAN 13 2007/ DISCUSSION...FORECAST FOCUS IS ON ACCUMULATION SNOW FOR SUNDAY EVENING THROUGH MONDAY MORNING. TODAY SHOULD GENERALLY BE QUIET WITH ONLY SOME LAKE EFFECT FLURRIES OR PATCHY FREEZING DRIZZLE. INVERSION IS ONLY AROUND 3K FEET AND BUFFY IS INDICATING THE POSSIBILITY OF PATCHY FREEZING DRIZZLE DUE TO THE LACK OF ICE CRYSTALS ABOVE 7K FEET. DELTA-T AROUND 12 DEGREES. A MID LEVEL DISTURBANCE MOVES ACROSS THE CWA TONIGHT. THERE IS SOME FRONTOGENETIC FORCING BETWEEN H850 AND H700...BUT LITTLE ADDITIONAL DYNAMICS. THE NAM SOLUTION TONIGHT IS MUCH STRONGER WITH THE MID AND UPPER LEVEL DYNAMICS...AND CONSEQUENTLY CRANKS OUT BETWEEN 1 AND 2 INCHES. THE NAM HOWEVER SEEMS TOO STRONG COMPARED TO THE REST OF THE MODELS. I WILL GENERALLY STAY WITH GFS POPS. SNOW ACCUMULATIONS WILL MAINLY BE LESS THAN 1/2 INCH. A MORE VIGOROUS SYSTEM MOVES ACROSS SOUTHERN WISCONSIN FROM SUNDAY EVENING THROUGH MONDAY MORNING. THERE IS SIGNIFICANT DIFFERENCES BETWEEN GFS AND NAM SOLUTION...WITH THE NAM BRINGING THE SURFACE LOW AND H850 BAROCLINIC ZONE MUCH FURTHER NORTH. THE NAM APPEARS TO BE THE OUTLIER HERE. I PREFER THE GFS SOLUTION WHICH KEEPS THE SURFACE SYSTEM AND H850 BAROCLINIC ZONE MUCH FURTHER SOUTH. HPC ALSO FAVORS GFS AND ECMWF SOLUTION. HPC SNOW AMOUNTS BRINGS 4 INCHES TO NEAR THE ILLINOIS BORDER...BUT SOUTHERN WISCONSIN HAS 2-3 INCHES AS PER THE GFS QPF WITH A 15 TO 1 RATIO. WITHOUT THE LOWER LEVEL FORCING...ONLY SOME VORTICITY CENTERS AND MID LEVEL FRONTOGENETIC FORCING IS AVAILABLE. AT THIS TIME...IT APPEARS THAT THE LAKE WILL HAVE MINIMAL INFLUENCE ON SNOW AMOUNTS. THE INVERSION STAYS BETWEEN 3-5K FEET THROUGH THE CRITICAL PERIOD...AND DELTA-T NEVER EXCEEDS 14 DEGREES. WILL STAY CLOSE TO GFS SOLUTION WITH POPS AND SNOW AMOUNTS. MKX WATCHES/WARNINGS/ADVISORIES... NONE. $$ && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99 wi