SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 940 AM PST WED JAN 18 2006 UPDATED AVIATION SECTION .SHORT TERM...HAVE ISSUED AN UPDATE THIS MORNING TO REFRESH WORDING. SURFACE TROUGH WAS CENTERED OVER SANTA BARBARA CHANNEL THIS MORNING. ISOLATED SHOWERS WERE TAPERING OFF OVER SANTA BARBARA COUNTY AND LATEST RUC INITIALIZED TROUGH AND TREND REASONABLY WELL. REMNANTS OF SURFACE TROUGH AND MOISTURE WILL MOVE OVER LA COUNTY BY EARLY AFTERNOON AND ISOLATED SHOWERS WILL END BY EARLY AFTERNOON SOUTH OF POINT CONCEPTION. WILL CONTINUE TO MENTION ISOLATED SHOWERS ALONG THE COAST NORTH OF POINT CONCEPTION THIS AFTERNOON AS ISOLATED SHOWERS UPSTREAM MOVE SOUTH WITHIN THE ACCELERATING NORTHWEST FLOW. UPPER JET MOVES ASHORE SUPPORTING STRONG COLD ADVECTION AND DESCENDING FLOW OVER THE AREA OVERNIGHT. STRONG AND POTENTIALLY DAMAGING NORTHWEST WINDS WILL ACCELERATE OVER SANTA BARBARA AND VENTURA COUNTY MOUNTAINS AND SOUTH SANTA BARBARA COAST OVERNIGHT. LONG TERM...AVIATION...MARINE DISCUSSION WRITTEN BY PREVIOUS SHIFT. .LONG TERM (FRI NIGHT-TUESDAY)... MODELS CONT TO HAVE A TOUGH TIME WITH THE EXTENDED PERIOD. ALL MODELS HAVE BACKED OFF THE PREVIOUS SOLUTION WHICH SHOWED A DECENT CHANCE OF RAIN ACROSS THE AREA ON SUN INTO MON. NOW...THEY SHOW GENERALLY NWLY FLOW ALF WITH VARIOUS SHORT WAVE TROUGHS MOVING THROUGH THE FLOW...BUT THE ATMOSPHERE REMAINS FAIRLY DRY. AT THIS TIME...AND UPON COORDINATION WITH SURROUNDING OFFICES...HAVE DROPPED POPS FOR SUN THRU MON. SHOULD CONT ON THE COOL SIDE INTO EARLY NEXT WEEK. BRUNO && .AVIATION... WEAK COLD FRONT CONTINUES TO MOVE SOUTHWARD INTO VENTURA COUNTY THIS MORNING. AT THIS POINT...IT APPEARS THAT THIS FRONT WILL BE DRY BUT SHOULD BRING SOME INCREASING LOWER LEVEL CLOUDS INTO LA/VTU COUNTIES FOR THE REMAINDER OF THE DAY. MEANWHILE...A MOIST ATMOSPHERE WILL CONTINUE TO BRING MVFR CONDITIONS TO KPRB...KSMX...AND KSBP THROUGH THE DAY...WITH LOCAL IFR CONDITIONS NEAR ISOLATED SHOWERS. A FEW AREAS OF CONCERN TODAY WILL BE THE NORTHERN SLOPES OF THE TEHACHAPI MTNS WITH VISBYS AOB 005 WITH -SHSN THIS EVENING AND OVERNIGHT HOURS. STRONG WINDS WILL DEVELOP ACROSS THE SBA MOUNTAINS AND SBA SOUTH COAST FOOTHILLS WHICH WILL AFFECT KSBA WITH SOME STRONG UDDFS AND LLWS BY THIS EVENING. KLAX WILL SEE EAST TO SE WINDS LESS THAN 6 KT THIS MORNING...THEN BECOMING W AT 12 KT BY NOON AND CONTINUE THROUGH THE EVENING...FINALLY BECOMING NORTHERLY OVERNIGHT. .MARINE... ANOTHER LARGE W SWELL WILL AFFECT THE COASTAL WATERS OF CENTRAL AND SOUTHERN CALIFORNIA THIS AFTERNOON THROUGH FRIDAY MORNING. SWELLS WILL RANGE BETWEEN 12 AND 16 FT N OF POINT CONCEPTION...TO 6 TO 10 FT IN THE INNER WATERS. SWELL PERIOD WILL BE BETWEEN 15-17 SECONDS. HIGH SURF ADVISORY IN EFFECT FOR THE CENTRAL COAST VALID FROM THIS EVENING THROUGH THURSDAY NIGHT...WHERE BREAKERS OF 10 TO 15 FEET WILL BE COMMON. LOCAL SETS AS HIGH AS 18 FEET WILL BE POSSIBLE DURING THE PEAK OF THE EVENT ON THURSDAY. WITH A SWELL DIRECTION OF 280 DEGREES...A GOOD PORTION OF THIS SWELL ENERGY IS EXPECTED TO MOVE INTO THE INNER COASTAL WATERS. FOR NOW...WILL JUST HIGHLIGHT THE LIKELIHOOD OF ABOVE NORMAL SURF FOR WEST FACING BEACHES SOUTH OF POINT CONCEPTION...WHERE BREAKERS OF 5 TO 7 FEET WITH LOCAL SETS TO 9 FEET CAN BE EXPECTED. LATER SHIFTS MAY NEED TO UPGRADE AREAS SOUTH OF POINT CONCEPTION TO A HIGH SURF ADVISORY. KAPLAN .LOX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY (SEE LAXNPWLOX). SMALL CRAFT ADVISORY (SEE LAXCWFLOX). HIGH SURF ADVISORY (SEE LAXCFWLOX). && $$ PUBLIC...FORWOOD AVIATION...GOMBERG ca SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 900 AM PST WED JAN 18 2006 .SHORT TERM...HAVE ISSUED AN UPDATE THIS MORNING TO REFRESH WORDING. SURFACE TROUGH WAS CENTERED OVER SANTA BARBARA CHANNEL THIS MORNING. ISOLATED SHOWERS WERE TAPERING OFF OVER SANTA BARBARA COUNTY AND LATEST RUC INITIALIZED TROUGH AND TREND REASONABLY WELL. REMNANTS OF SURFACE TROUGH AND MOISTURE WILL MOVE OVER LA COUNTY BY EARLY AFTERNOON AND ISOLATED SHOWERS WILL END BY EARLY AFTERNOON SOUTH OF POINT CONCEPTION. WILL CONTINUE TO MENTION ISOLATED SHOWERS ALONG THE COAST NORTH OF POINT CONCEPTION THIS AFTERNOON AS ISOLATED SHOWERS UPSTREAM MOVE SOUTH WITHIN THE ACCELERATING NORTHWEST FLOW. UPPER JET MOVES ASHORE SUPPORTING STRONG COLD ADVECTION AND DESCENDING FLOW OVER THE AREA OVERNIGHT. STRONG AND POTENTIALLY DAMAGING NORTHWEST WINDS WILL ACCELERATE OVER SANTA BARBARA AND VENTURA COUNTY MOUNTAINS AND SOUTH SANTA BARBARA COAST OVERNIGHT. LONG TERM...AVIATION...MARINE DISCUSSION WRITTEN BY PREVIOUS SHIFT. .LONG TERM (FRI NIGHT-TUESDAY)... MODELS CONT TO HAVE A TOUGH TIME WITH THE EXTENDED PERIOD. ALL MODELS HAVE BACKED OFF THE PREVIOUS SOLUTION WHICH SHOWED A DECENT CHANCE OF RAIN ACROSS THE AREA ON SUN INTO MON. NOW...THEY SHOW GENERALLY NWLY FLOW ALF WITH VARIOUS SHORT WAVE TROUGHS MOVING THROUGH THE FLOW...BUT THE ATMOSPHERE REMAINS FAIRLY DRY. AT THIS TIME...AND UPON COORDINATION WITH SURROUNDING OFFICES...HAVE DROPPED POPS FOR SUN THRU MON. SHOULD CONT ON THE COOL SIDE INTO EARLY NEXT WEEK. BRUNO && .AVIATION... AS WEAK COLD FRONT CONTINUES TO MOVE S ACROSS POINT CONCEPTION THIS MORNING...IT WILL CONTINUE TO FALL APART AS IT REACHES VENTURA AND LOS ANGELES COUNTIES. SPOTTY SHOWERS WILL BE CONFINED TO SAN LUIS OBISPO COUNTY AND A FEW DROPS IN THE MOST NORTHERN AREAS OF SANTA BARBARA COUNTY WILL BE POSSIBLE THIS MORNING. OTHERWISE...CIGS WILL REMAIN IN MVFR CATEGORY THROUGH MOST OF THE DAY TO THE NORTH...WITH LOCAL IFR CONDS NEAR SHOWERS. AREAS S OF POINT CONCEPTION WILL CONTINUE TO SEE HIGH CLOUDS STREAM IN OVER THE AREA WITH LOW CLOUDS DEVELOPING LATER IN THE EVENING WHICH SHOULD BRING POSSIBLE MVFR CIGS AND VSBYS AFTER SUNSET. A FEW AREAS OF CONCERN TODAY WILL BE THE NORTHERN SLOPES OF THE TEHACHAPI MTNS WITH VISBYS AOB 005 WITH -SHSN THIS EVENING AND OVERNIGHT HOURS. STRONG WINDS WILL DEVELOP ACROSS THE SBA MOUNTAINS AND SBA SOUTH COAST FOOTHILLS WHICH WILL AFFECT KSBA WITH SOME MODERATE LLWS BY LATE THIS AFTERNOON. KLAX WILL SEE EAST TO SE WINDS LESS THAN 6 KT THIS MORNING...THEN BECOMING W AT 12 KT BY NOON AND CONTINUE THROUGH THE EVENING. KAPLAN .MARINE... ANOTHER LARGE W SWELL WILL AFFECT THE COASTAL WATERS OF CENTRAL AND SOUTHERN CALIFORNIA THIS AFTERNOON THROUGH FRIDAY MORNING. SWELLS WILL RANGE BETWEEN 12 AND 16 FT N OF POINT CONCEPTION...TO 6 TO 10 FT IN THE INNER WATERS. SWELL PERIOD WILL BE BETWEEN 15-17 SECONDS. HIGH SURF ADVISORY IN EFFECT FOR THE CENTRAL COAST VALID FROM THIS EVENING THROUGH THURSDAY NIGHT...WHERE BREAKERS OF 10 TO 15 FEET WILL BE COMMON. LOCAL SETS AS HIGH AS 18 FEET WILL BE POSSIBLE DURING THE PEAK OF THE EVENT ON THURSDAY. WITH A SWELL DIRECTION OF 280 DEGREES...A GOOD PORTION OF THIS SWELL ENERGY IS EXPECTED TO MOVE INTO THE INNER COASTAL WATERS. FOR NOW...WILL JUST HIGHLIGHT THE LIKELIHOOD OF ABOVE NORMAL SURF FOR WEST FACING BEACHES SOUTH OF POINT CONCEPTION...WHERE BREAKERS OF 5 TO 7 FEET WITH LOCAL SETS TO 9 FEET CAN BE EXPECTED. LATER SHIFTS MAY NEED TO UPGRADE AREAS SOUTH OF POINT CONCEPTION TO A HIGH SURF ADVISORY. KAPLAN .LOX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY (SEE LAXNPWLOX). SMALL CRAFT ADVISORY (SEE LAXCWFLOX). HIGH SURF ADVISORY (SEE LAXCFWLOX). && $$ PUBLIC...FORWOOD AVIATION...GOMBERG ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1020 AM CST WED JAN 18 2006 .DISCUSSION... 16Z SURFACE CHART SHOWS RIDGE AXIS BUILDING INTO CENTRAL ILLINOIS. LOW CLOUD COVER PERSISTS ACROSS THE EASTERN KILX CWA...BUT HAS CLEARED LOCATIONS ALONG AND WEST OF I-55. BASED ON LATEST SATELLITE LOOPS AND 12Z NAM/RUC RH PROFILES...CLOUDS WILL CLEAR THE EAST SHORTLY AFTER 18Z. MID-LEVEL CLOUDS ASSOCIATED WITH WEAK SHORT-WAVE SLIDING INTO THE GREAT LAKES WILL REMAIN JUST NORTH OF THE AREA THIS AFTERNOON. MEANWHILE...A SECOND WAVE WILL PUSH EASTWARD FROM THE PLAINS STATES...SPREADING SCT MID CLOUDS ACROSS WEST-CENTRAL ILLINOIS BY LATE AFTERNOON/EVENING. BOTTOM LINE WILL BE A MOSTLY SUNNY AFTERNOON ACROSS THE KILX CWA...WITH INCREASING CLOUDS NOTED BY LATE IN THE DAY. CURRENT TEMPS AROUND THE AREA RANGE FROM THE MIDDLE 20S NORTH...TO THE LOWER 30S SOUTH. FORECAST HIGHS APPEAR TO BE ON TRACK...BUT HAVE TWEAKED DOWN JUST A BIT BASED ON SLIGHTLY SLOWER THAN ANTICIPATED MORNING RISES. && PREV DISCUSSION... UPPER LEVEL LOW RIGHT OVERHEAD WITH TROF EXTENDING INTO THE GULF STATES. SFC LOW NE OF LAKE HURON...AND FRONT DRAPED ALONG THE ERN SEABOARD. STILL IN A BIT OF CYCLONIC FLOW...AND LOW LEVEL CLOUDS LINGER ACROSS THE CWA. FOLLOWING SATELLITE TRENDS...THE BACK EDGE OF THE CLOUD DECK SHOULD BE MAKING ITS WAY INTO THE WRN CWA BY MID MORNING. SCATTERED FLURRIES NORTH OF INTERSTATE 74 ARE SHOWING A DWINDLING TREND AS WELL...ALREADY ENDING IN ERN IA. FORECAST CHALLENGES IN THE SHORT TERM ARE THE PROGRESSION OF THE CLOUD DECK AND FLURRIES...AND THE RESULTING EFFECT ON HIGH TEMPS FOR THE DAY. FORECAST CHALLENGE OF THE LONG TERM REMAINS FRI/SAT SYSTEM. MODEL PERFORMANCE...WITH A WEEK OF STRUGGLING WITH CONSISTENCY...IS IT ANY WONDER THAT THE MODELS DIVERGE PRECISELY WHEN THE UPPER LEVEL LOW IS MOVING OVER ILLINOIS IN THE MODEL WITH THE MOST RUN TO RUN CONSISTENCY OF LATE? THE GFS NOW SHOWS A CLOSED LOW WITH THE FRI/SAT SYSTEM...WHILE THE ECMWF HAS LITTLE MORE THAN A WEAK SHORTWAVE. WHEREAS THE NAM BRINGS THE SYSTEM THROUGH...IT IS A TOUCH WEAKER AND SLOWER...AND THE UPPER LEVEL LOW IS IN CENTRAL IL AT FH84...WHERE THE NAM LEAVES OFF. AM SURE THAT FORECASTS WILL TAKE ON FAR MORE DETAIL WITH THIS SYSTEM FROM HERE ON OUT. AS IT IS...NAM AND CAN GLOBAL STARTING TO LOOK SIMILAR...BUT CANNOT RULE OUT THE CONSISTENCY OF THE GFS. SHORT TERM...TODAY THROUGH FRIDAY... HIGH PRESSURE BUILDING BACK INTO THE AREA BEHIND TODAYS EXITING STRATOCU DECK. TEMPS SHOULD BE ON THE RISE WITH THE RETURN OF THE SUNSHINE...AND WILL BE ONLY SLIGHTLY WARMER THAN YESTERDAYS. SRLY FLOW KICKS BACK IN AGAIN BY THIS EVENING...FEEDING THE WARMER AIR BACK INTO THE AREA...AS A HIGH BUILDS IN OVER THE GULF STATES. MOISTURE RETURN FROM THIS FLOW WILL ALSO BEGIN AT THE LOW LEVELS...THOUGH LAYER RH WILL BE SLIGHTLY LIMITED...WITH RATHER RAPID ZONAL FLOW FROM THE MID LEVELS UP. MODELS SHOW A RATHER WEAK SFC FEATURE MOVING THROUGH THURSDAY. HPC HAS AGREED WITH THEIR HAND PROGS...AND HAVE A WARM FRONT APPROACHING THE CWA FROM THE SW. CONSIDERING THE LOW LEVEL MOISTURE...WILL LEAVE THE SLIGHT POPS IN THE FCST AT THIS TIME...THOUGH THE BETTER DYNAMICS CERTAINLY COME ALONG LATE ON FRIDAY...AND INTO SATURDAY. BY FRIDAY AFTERNOON...ANOTHER SFC BOUNDARY IS SETTING UP IN ASSOCIATION WITH A LOW MOVING OUT OF THE SW...MUCH BETTER MOISTURE FIELDS...AND BETTER REPRESENTATION IN THICKNESS FIELDS AS WELL. POPS SPREADING FROM THE SOUTH...INTO THE ENTIRE CWA...AND INTO THE OVERNIGHT HOURS ON SAT AM. PLENTY OF CLOUDS AND ALREADY WARM TEMPS SHOULD KEEP THIS SYSTEM IN THE RAIN CATEGORY FOR FRIDAY...AND INTO FRIDAY NIGHT. AFTER MIDNIGHT...CHANCES FOR THUNDER INCREASE FURTHER SOUTH...AND WILL KEEP THUNDER GRIDS IN THE SE...WITH ISOLATED THUNDER JUST NORTH OF THAT UP TO INTERSTATE 72. LONG TERM...SATURDAY THROUGH TUESDAY... STORM SYSTEM PROGGED TO BEGIN MOVING QUICKLY AT ABOUT THE SAME TIME ENOUGH CAA HAS TAKEN PLACE TO SEE THE SWITCH OVER TO SNOW. SATURDAY MORNING SHOULD BEGIN WITH SNOW...WITH THE BEST CHANCES FOR ACCUMULATION CLOSEST TO THE COOLER SFC TEMPS ALONG AND NW OF THE RIVER. HAVE KEPT THE FCST ALL RAIN SLIGHTLY LONGER GIVEN THE WARM TEMPS...AND THE TENDENCY OF THE SYSTEMS TO BE SLOWER TO EVOLVE OF LATE. TEMPS SHOULD FALL OR REMAIN STEADY THROUGHOUT MOST OF SATURDAY...THOUGH STILL SLIGHTLY ABOVE NORMAL. THE PATTERN WILL OF SLIGHTLY ABOVE NORMAL TEMPS SHOULD CONTINUE...WITH ANOTHER SYSTEM PROGGED TO KICK OUT OF THE SW FOR THE NEXT ROUND MID WORK WEEK. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BARNES/HJS il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1230 PM EST WED JAN 18 2006 .AVIATION... LATEST SFC OBS AND VIS SAT SHOWING CLEARING SKIES NEAR SBN AND EXPECT SCT CONDITIONS THERE BY 19Z. WEAKENING TREND IN ECHOES NOTED ON KIWX RADAR LOOP AS DRY AIR MOVES INTO THE AREA AND UPPER SHORT WAVE CONTINUES SOUTHEAST PUSH TOWARD SOUTHERN INDIANA. ANY FLURRIES STILL IN VICINITY OF FWA AT ISSUANCE TIME WILL HAVE NO IMPACT ON VSBYS SO NO PLAN TO MENTION IN TAF. MVFR CIGS AT FWA SHOULD ALSO SCATTER OUT WITHIN A COUPLE HOURS THIS AFTERNOON. BREEZY CONDITIONS ACROSS THE AREA THROUGH THE AFTERNOON HOURS WILL KEEP MENTION OF G25 AT BOTH SITES. DIMINISHING WINDS AND VFR CONDITIONS EXPECTED REMAINDER OF TAF PERIOD WITH MID LEVEL CLOUDS ON LEADING EDGE OF WAA EXPECTED TO MOVE IN OVERNIGHT. && .UPDATE... WATER VAPOR LOOP SHOWING SHORT WAVE DIVING SOUTHEAST INTO NORTHERN ILLINOIS TRIGGERING LIGHT SNOW/FLURRIES OVER THE AREA. SKIES CLEARING OUT TO OUR WEST WITH CLOUDS BEGINNING TO BREAK UP OVER SOUTHERN AND WESTERN PORTIONS OF OUR CWA. LATEST RUC HAS SHORT WAVE CONTINUING SOUTHEAST MOVEMENT INTO OHIO VALLEY THIS AFTERNOON AND SHOULD ALLOW FLURRIES TO MOVE OUT OF THE AREA ALONG WITH SOME CLEARING SKIES. 850MB THERMAL TROUGH OVER THE AREA RIGHT NOW WILL SHIFT EAST THIS AFTERNOON. PERSISTENT W/SW FLOW WILL TRANSITION QUICKLY INTO WAA LATER TODAY WHICH ALONG WITH SOME SUN SHOULD ALLOW SOME RECOVERY IN THE WESTERN CWA...BUT SEE LITTLE CHANCE FOR MUCH CHANGE IN THE EAST. WILL STILL BACK DOWN HIGHS A COUPLE IN THE WEST AND PROBABLY HOLD TEMPS STEADY IN THE EAST. && .PREV DISCUSSION... SHORT TERM... BASED ON MOVEMENT OF VORT MAX OVER SW OH ON WATER VAPOR IMAGERY, EXPECT THE SNOW IN THE DEFORMATION ZONE TO ITS NW AND OVER ERN PORTION OF OUR CWA WILL LIFT NE OF THE CWA BY DAYBREAK, HWVR WITH SNOW STILL ONGOING AT ZFP ISSUANCE TIME, WILL HAVE TO MENTION SNOW TAPERING OFF EARLY THIS MORNING OVER ERN PORTIONS. OTRWS, WITH MOIST CYCLONIC FLOW OVER THE AREA THIS MORNING, WILL HAVE A CHC OF FLURRIES, BUT DROPPED SNOW SHOWER POPS. INVERSION BASED AROUND 3K FT WITH LOW LEVELS DRYING, A WNW FETCH, AND DELTA T'S ONLY AROUND 13C SUGGESTS MEASURABLE LES UNLIKELY TODAY. LOW LEVEL CAA WILL TRANSITION TO WAA THIS AFTN AS SFC RIDGE MOVES INTO THE AREA. DRIER AIR AND FAIRLY STRONG LOW LEVEL FLOW SHOULD RESULT IN SOME CLRG, ESPECIALLY OVER WRN PORTIONS OF CWA. TAMDAR SOUNDINGS UPSTREAM AT RFD THIS MORNING SHOW LOW LEVELS WELL MIXED, AND WITH A COUPLE INCHES OF NEW SNOW ON THE GROUND HERE, TEMPS WILL STRUGGLE TO RISE THIS AFTN WITH HIGHS MAINLY IN THE L30S. SFC RIDGE WILL MOVE ACROSS THE CWA THIS EVE. NAM FCSTG STRONGER GRADIENT AND WAA THAN GFS WITH RISING TEMPS OVERNIGHT. EXPECT THERE WILL BE SOME RADIATIONAL COOLING WITH SNOW COVER REMAINING INTO TNGT AND SOME BREAKS IN WAA MID/HI CLOUDS ALLOWING FOR BOUNDARY LAYER DECOUPLING... THUS WENT A LITTLE BLO COOLEST MOS MINS. LONG TERM... THURSDAY THROUGH TUESDAY THE VERY ACTIVE HIGH ZONAL FLOW WILL CONTINUE THROUGH AT LEAST THE FIRST HALF OF THE MEDIUM RANGE PERIOD. THE FIRST PACIFIC SHORTWAVE TO AFFECT THE PERIOD WILL TRAVERSE THE ROCKIES TODAY AND SPAWN WEAK LEE CYCLOGENESIS OVER THE HIGH PLAINS. THIS SHORTWAVE WILL REMAIN LOW AMPLITUDE AND AS SUCH MAINTAIN ONLY A WEAK SURFACE REFLECTION. THE PRIMARY INFLUENCE OF THIS FIRST SHORTWAVE WILL BE TO ONCE AGAIN TURN THE LOW/MID LEVEL FLOW S/SW AND BRING A RETURN TO WELL ABOVE NORMAL TEMPS. HIGH TEMPS BOTH THU AND FRI WILL RANGE FROM THE MID 40S NORTH TO UPPER 40S SOUTH. HAVE KEPT TEMPS A LITTLE BELOW GUIDANCE FOR THU IN ANTICIPATION THAT A MINOR AMOUNT OF SNOW WILL STILL BE ON THE GROUND TO TEMPER THE WARMUP SOMEWHAT. HAVE INTRODUCED LOW CHANCE POPS FOR FRI WITH A BAROCLINIC ZONE CROSSING THE CWA INITIALLY...THEN STALLING JUST SOUTH OF THE CWA WITH INCREASING WAA/ISENTROPIC LIFT BY LATE AFTERNOON ATOP THE STALLING SURFACE FRONT AS THE NEXT SYSTEM ORGANIZES UPSTREAM. THE NEXT MUCH STRONGER PACIFIC SHORTWAVE CAN BE SEEN ON WATER VAPOR IMAGERY EARLY THIS MORNING CENTERED NEAR 44N 135W AND APPROACHING THE PACIFIC NORTHWEST. IMPRESSIVE SATELLITE PRESENTATION WITH A WELL DEFINED MID LEVEL CIRCULATION AND IMPLIED COLD POOL. MODEL GUIDANCE IN GENERAL AGREEMENT IN TAKING THIS SHORTWAVE ACROSS THE ROCKIES AND YIELDING ANOTHER LEE CYCLONE ON FRI. AS TO BE EXPECTED AT THIS TIME STEP...MODELS DIFFER WITH RESPECT TO THE EXACT TRACK AND DETAILS OF THE SYSTEM. 12Z/17 GFS HAD TRENDED TOWARD A FARTHER NORTH AND WARMER SOLUTION...WHILE THE 00Z/18 RUN HAS TRENDED THE OTHER WAY TOWARD A MORE SOUTHERLY AND COLDER SOLUTION. GIVEN THE MODEL DIFFERENCES WILL FOLLOW A MEAN SOLUTION OF THE AVAILABLE MEDIUM RANGE GUIDANCE...INCLUDING THE GFS/ECMWF/UKMET/GEM. THIS WILL ALSO ALLOW FOR ONLY MINOR CHANGES TO FORECAST CONTINUITY. WILL CONTINUE WITH ALL RAIN FOR FRI NGT INTO SAT AND RAISE POPS TO HIGH CHANCE FRI NGT AND LIKELY FOR SAT. WHILE THE LATEST GFS/NAM SOLUTIONS WOULD SUGGEST SOME POTENTIAL FOR SNOW ACROSS THE NORTH FRI NGT/SAT IT IS PRUDENT TO WAIT FOR SEVERAL MORE MODEL ITERATIONS BEFORE JUMPING ON THE COLDER SOLUTION. HAVE DECREASED TEMPS FOR FRI NGT THROUGH SAT BY A FEW DEGREES HOWEVER AS THE 12Z/17 MEX GUIDANCE WAS WARM COMPARED TO OTHER PREVIOUS AND CURRENT MODEL RUNS. WITH THE PATTERN REMAINING PROGRESSIVE THIS SYSTEM WILL PULL OUT ON SAT NGT WITH RAIN POSSIBLY CHANGING TO SOME SNOW BEFORE ENDING AS WRAP AROUND MOISTURE CROSSES THE CWA. THEN HIGH PRESSURE BUILDS IN FOR SUN WITH COOL BUT STILL ABOVE NORMAL TEMPS. NEXT PACIFIC SHORTWAVE ALREADY DIGGING THROUGH THE INTERMOUNTAIN WEST ON SUNDAY. SIGNIFICANT MODEL DIFFERENCES AND RUN TO RUN DISCONTINUITIES WITH RESPECT TO THE HANDLING OF THIS NEXT PACIFIC SHORTWAVE. GFS/ECMWF BOTH HINTING AT SOME POTENTIAL FOR YET ANOTHER SYSTEM FOR MON OR TUE NEXT WEEK. GIVEN THE SIGNIFICANT TIMING AND TRACK DIFFERENCES WITH THIS SYSTEM WILL REFRAIN FROM INTRODUCING POPS AT THIS TIME UNTIL THE TIMING CAN BE BETTER DETERMINED. .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR LMZ043 AND LMZ046. && $$ SHORT TERM/AVIATION...JT LONG TERM....HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1130 AM EST WED JAN 18 2006 .UPDATE... WATER VAPOR LOOP SHOWING SHORT WAVE DIVING SOUTHEAST INTO NORTHERN ILLINOIS TRIGGERING LIGHT SNOW/FLURRIES OVER THE AREA. SKIES CLEARING OUT TO OUR WEST WITH CLOUDS BEGINNING TO BREAK UP OVER SOUTHERN AND WESTERN PORTIONS OF OUR CWA. LATEST RUC HAS SHORT WAVE CONTINUING SOUTHEAST MOVEMENT INTO OHIO VALLEY THIS AFTERNOON AND SHOULD ALLOW FLURRIES TO MOVE OUT OF THE AREA ALONG WITH SOME CLEARING SKIES. 850MB THERMAL TROUGH OVER THE AREA RIGHT NOW WILL SHIFT EAST THIS AFTERNOON. PERSISTANT W/SW FLOW WILL TRANSITION QUICKLY INTO WAA LATER TODAY WHICH ALONG WITH SOME SUN SHOULD ALLOW SOME RECOVERY IN THE WESTERN CWA...BUT SEE LITTLE CHANCE FOR MUCH CHANGE IN THE EAST. WILL STILL BACK DOWN HIGHS A COUPLE IN THE WEST AND PROBABLY HOLD TEMPS STEADY IN THE EAST. .AVIATION... LOW PRESSURE OVER SE ONTARIO WILL MOVE NE INTO QUEBEC TODAY WHILE A RIDGE MOVES EAST FROM THE MS RVR VALLEY ACROSS NRN INDIANA TONIGHT. BACK EDGE OF STRATO CU DECK WITH GENERALLY MVFR CIGS WAS MOVG EAST ACROSS WI/NW IL THIS MORNING AND SHOULD CLEAR SBN/FWA THIS AFTN. SOME MID/HIGH CLOUDS EXPECTED TONIGHT IN THE DVLPG STRONG WAA REGIME. && .PREV DISCUSSION... SHORT TERM... BASED ON MOVEMENT OF VORT MAX OVER SW OH ON WATER VAPOR IMAGERY, EXPECT THE SNOW IN THE DEFORMATION ZONE TO ITS NW AND OVER ERN PORTION OF OUR CWA WILL LIFT NE OF THE CWA BY DAYBREAK, HWVR WITH SNOW STILL ONGOING AT ZFP ISSUANCE TIME, WILL HAVE TO MENTION SNOW TAPERING OFF EARLY THIS MORNING OVER ERN PORTIONS. OTRWS, WITH MOIST CYCLONIC FLOW OVER THE AREA THIS MORNING, WILL HAVE A CHC OF FLURRIES, BUT DROPPED SNOW SHOWER POPS. INVERSION BASED AROUND 3K FT WITH LOW LEVELS DRYING, A WNW FETCH, AND DELTA T'S ONLY AROUND 13C SUGGESTS MEASURABLE LES UNLIKELY TODAY. LOW LEVEL CAA WILL TRANSITION TO WAA THIS AFTN AS SFC RIDGE MOVES INTO THE AREA. DRIER AIR AND FAIRLY STRONG LOW LEVEL FLOW SHOULD RESULT IN SOME CLRG, ESPECIALLY OVER WRN PORTIONS OF CWA. TAMDAR SOUNDINGS UPSTREAM AT RFD THIS MORNING SHOW LOW LEVELS WELL MIXED, AND WITH A COUPLE INCHES OF NEW SNOW ON THE GROUND HERE, TEMPS WILL STRUGGLE TO RISE THIS AFTN WITH HIGHS MAINLY IN THE L30S. SFC RIDGE WILL MOVE ACROSS THE CWA THIS EVE. NAM FCSTG STRONGER GRADIENT AND WAA THAN GFS WITH RISING TEMPS OVERNIGHT. EXPECT THERE WILL BE SOME RADIATIONAL COOLING WITH SNOW COVER REMAINING INTO TNGT AND SOME BREAKS IN WAA MID/HI CLOUDS ALLOWING FOR BOUNDARY LAYER DECOUPLING... THUS WENT A LITTLE BLO COOLEST MOS MINS. LONG TERM... THURSDAY THROUGH TUESDAY THE VERY ACTIVE HIGH ZONAL FLOW WILL CONTINUE THROUGH AT LEAST THE FIRST HALF OF THE MEDIUM RANGE PERIOD. THE FIRST PACIFIC SHORTWAVE TO AFFECT THE PERIOD WILL TRAVERSE THE ROCKIES TODAY AND SPAWN WEAK LEE CYCLOGENESIS OVER THE HIGH PLAINS. THIS SHORTWAVE WILL REMAIN LOW AMPLITUDE AND AS SUCH MAINTAIN ONLY A WEAK SURFACE REFLECTION. THE PRIMARY INFLUENCE OF THIS FIRST SHORTWAVE WILL BE TO ONCE AGAIN TURN THE LOW/MID LEVEL FLOW S/SW AND BRING A RETURN TO WELL ABOVE NORMAL TEMPS. HIGH TEMPS BOTH THU AND FRI WILL RANGE FROM THE MID 40S NORTH TO UPPER 40S SOUTH. HAVE KEPT TEMPS A LITTLE BELOW GUIDANCE FOR THU IN ANTICIPATION THAT A MINOR AMOUNT OF SNOW WILL STILL BE ON THE GROUND TO TEMPER THE WARMUP SOMEWHAT. HAVE INTRODUCED LOW CHANCE POPS FOR FRI WITH A BAROCLINIC ZONE CROSSING THE CWA INITIALLY...THEN STALLING JUST SOUTH OF THE CWA WITH INCREASING WAA/ISENTROPIC LIFT BY LATE AFTERNOON ATOP THE STALLING SURFACE FRONT AS THE NEXT SYSTEM ORGANIZES UPSTREAM. THE NEXT MUCH STRONGER PACIFIC SHORTWAVE CAN BE SEEN ON WATER VAPOR IMAGERY EARLY THIS MORNING CENTERED NEAR 44N 135W AND APPROACHING THE PACIFIC NORTHWEST. IMPRESSIVE SATELLITE PRESENTATION WITH A WELL DEFINED MID LEVEL CIRCULATION AND IMPLIED COLD POOL. MODEL GUIDANCE IN GENERAL AGREEMENT IN TAKING THIS SHORTWAVE ACROSS THE ROCKIES AND YIELDING ANOTHER LEE CYCLONE ON FRI. AS TO BE EXPECTED AT THIS TIME STEP...MODELS DIFFER WITH RESPECT TO THE EXACT TRACK AND DETAILS OF THE SYSTEM. 12Z/17 GFS HAD TRENDED TOWARD A FARTHER NORTH AND WARMER SOLUTION...WHILE THE 00Z/18 RUN HAS TRENDED THE OTHER WAY TOWARD A MORE SOUTHERLY AND COLDER SOLUTION. GIVEN THE MODEL DIFFERENCES WILL FOLLOW A MEAN SOLUTION OF THE AVAILABLE MEDIUM RANGE GUIDANCE...INCLUDING THE GFS/ECMWF/UKMET/GEM. THIS WILL ALSO ALLOW FOR ONLY MINOR CHANGES TO FORECAST CONTINUITY. WILL CONTINUE WITH ALL RAIN FOR FRI NGT INTO SAT AND RAISE POPS TO HIGH CHANCE FRI NGT AND LIKELY FOR SAT. WHILE THE LATEST GFS/NAM SOLUTIONS WOULD SUGGEST SOME POTENTIAL FOR SNOW ACROSS THE NORTH FRI NGT/SAT IT IS PRUDENT TO WAIT FOR SEVERAL MORE MODEL ITERATIONS BEFORE JUMPING ON THE COLDER SOLUTION. HAVE DECREASED TEMPS FOR FRI NGT THROUGH SAT BY A FEW DEGREES HOWEVER AS THE 12Z/17 MEX GUIDANCE WAS WARM COMPARED TO OTHER PREVIOUS AND CURRENT MODEL RUNS. WITH THE PATTERN REMAINING PROGRESSIVE THIS SYSTEM WILL PULL OUT ON SAT NGT WITH RAIN POSSIBLY CHANGING TO SOME SNOW BEFORE ENDING AS WRAP AROUND MOISTURE CROSSES THE CWA. THEN HIGH PRESSURE BUILDS IN FOR SUN WITH COOL BUT STILL ABOVE NORMAL TEMPS. NEXT PACIFIC SHORTWAVE ALREADY DIGGING THROUGH THE INTERMOUNTAIN WEST ON SUNDAY. SIGNIFICANT MODEL DIFFERENCES AND RUN TO RUN DISCONTINUITIES WITH RESPECT TO THE HANDLING OF THIS NEXT PACIFIC SHORTWAVE. GFS/ECMWF BOTH HINTING AT SOME POTENTIAL FOR YET ANOTHER SYSTEM FOR MON OR TUE NEXT WEEK. GIVEN THE SIGNIFICANT TIMING AND TRACK DIFFERENCES WITH THIS SYSTEM WILL REFRAIN FROM INTRODUCING POPS AT THIS TIME UNTIL THE TIMING CAN BE BETTER DETERMINED. .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR LMZ043 AND LMZ046. && $$ SHORT TERM/AVIATION...JT LONG TERM....HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1050 PM EST WED JAN 18 2006 .UPDATE... MAIN FCST CONCERN IS POSSIBLE EXTENSION OF ADVY OVER THE ERN FCST AREA. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF CENTERED FROM JAMES BAY TO THE ERN GREAT LAKES CONTINUING TO MOVE E THIS EVENING WHILE FLAT RIDGE IS SLIDING E TO THE UPPER MISSISSIPPI VALLEY. 850MB THERMAL TROF WITH TEMPS AROUND -15C PER TAMDAR SOUNDING FROM FLIGHT OUT OF KSAW THIS EVENING IS BEGINNING TO PUSH E OF ERN LAKE SUPERIOR ATTM. WITH PASSAGE OF THERMAL TROF...WAA/LOWERING OF INVERSION HEIGHTS CAUSED A RAPID DIMINISHING OF LES INTO NW UPPER MI A FEW HRS AGO. THE WEAKENING TREND HAS NOT YET APPEARED IN LES AFFECTING ERN ALGER/NRN LUCE COUNTIES. KMQT RADAR SHOWS ONE DOMINANT BAND IMPACTING THE LAKESHORE AREAS FROM GRAND MARAIS EASTWARD...BUT IT IS SHIFTING SLIGHTLY N AS LAND BREEZE COMPONENT TO WIND STRENGTHENS. SPOTTER AT TWO HEART REPORTED A 12HR SNOW ACCUMULATION OF 4 INCHES AS OF ABOUT 01Z...BUT THERE WAS CONSIDERABLE BLSN AT OBSERVATION TIME DUE TO OPEN EXPOSURE TO STRONG WINDS ACROSS THE LAKE. AWAY FROM LES...STRATOCU HAS EXPANDED THIS EVENING OVER NEARLY ALL OF UPPER MI UNDERNEATH SUBSIDENCE INVERSION. WHERE SKIES HAVE REMAINED CLEAR ALONG THE WISCONSIN BORDER...TEMPS HAVE PLUMMETED TO AROUND ZERO IN A FEW SPOTS. WITH WAA GETTING UNDERWAY OVER ERN LAKE SUPERIOR IN ADDITION TO AIRMASS BECOMING DRIER AND INVERSION CONTINUING TO LOWER PER 00Z KINL SOUNDING AND AIRCRAFT SOUNDING FROM FLIGHT OUT OF KDLH...EXPECT LES TO WIND DOWN STEADILY OVERNIGHT. HOWEVER...STRENGTHENING LAND BREEZE (THUS ENHANCED CONVERGENCE) MAY ACT TO MAINTAIN THE CURRENT DOMINANT SRN LES BAND AFFECTING MAINLY FAR NRN LUCE COUNTY ATTM. SINCE 950-850MB WIND DIRECTION CHANGES LITTLE...THIS BAND MAY CONTINUE TO IMPACT FAR NRN LUCE COUNTY MUCH OF THE NIGHT. SO HAVE OPTED TO EXTEND LUCE COUNTY ADVY UNTIL 11Z FOR 1 TO 3 INCHES OF ADDITIONAL SNOWFALL. WILL ALLOW ALGER TO EXPIRE AT MIDNIGHT. LINGERING -SHSN/FLURRIES WILL CONTINUE TO DIMINISH ELSEWHERE TO THE W. AS FOR CLOUDS...NOT SURE THE STATOCU THAT HAS EXPANDED THIS EVENING WILL GET PUSHED OUT DURING THE NIGHT SINCE SFC RIDGE AXIS ONLY DRIFTS E...STRETCHING NW TO SE ACROSS FCST AREA BY 12Z. WILL PROBABLY SEE WRN EDGE OF STRATOCU EDGE E OVERNIGHT...BUT WHATEVER CLEARING DOES OCCUR WILL BE REPLACED BY MID/HIGH CLOUDS SPREADING E ACROSS MN/NW WI ATTM. MAKES FOR A TRICKY TEMP FCST...BUT COLDEST TEMPS SHOULD REMAIN CONFINED TO THE AREAS THAT HAVE BEEN CLEAR MOST OF THE EVENING ALONG THE WI BORDER. TEMPS AS LOW AS AROUND ZERO SHOULD STEADY OUT AND THEN RISE A BIT AS CLOUDS INCREASE. MOST AREAS THAT HAVE A STRATOCU DECK NOW SHOULD SEE MINS IN THE 10 TO 20F RANGE...ASSUMING SKIES DON'T CLEAR OUT FOR A WHILE. && .PREV DISCUSSION... ISSUED AT 331 PM EST THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR SNOW TONIGHT AND THURSDAY. WATER VAPOR IMAGERY AND RUC/NAM SHOWING A NEAR ZONAL FLOW BETWEEN A SHORTWAVE OVER THE EAST COAST AND ANOTHER OVER THE PACIFIC NORTHWEST. A WEAK SHORTWAVE IS OVER THE FORECAST AREA...EASTERN DAKOTAS AND IOWA...AND OVER WYOMING. SURFACE ANALYSIS INDICATE A LARGE LOW PRESSURE SYSTEM OVER QUEBEC AND THE EAST COAST...A RIDGE STRETCHING FROM MANITOBA SOUTH INTO CENTRAL TENNESSEE...AND ANOTHER DEEP LOW DEVELOPING OVER THE DAKOTAS. A WARM FRONT ACCOMPANYING THIS DAKOTA LOW EXTENDS SOUTHEAST INTO THE MIDDLE MISSISSIPPI RIVER VALLEY. ANOTHER LOW IS OVER CENTRAL SASKATCHEWAN. AN 850MB THERMAL TROUGH IS OVER ONTARIO PRODUCING A LAKE-850MB DELTA-T OF AROUND 17C. THIS IS PRODUCING A FEW LAKE EFFECT SNOW BANDS ACROSS THE FORECAST AREA. THE SHORTWAVE OVER THE FORECAST AREA WILL SHIFT INTO QUEBEC TONIGHT. THE SURFACE LOW WILL MOVE OUT OF THE NORTHERN PLAINS AND SWING TO THE SOUTH OF THE FORECAST AREA FORCING A RIDGE TO FORM ACROSS UPPER MICHIGAN. THE 850MB THERMAL TROUGH WILL RELOCATE OVER WESTERN QUEBEC OVERNIGHT...INDICATING WARM AIR ADVECTION AND A REDUCING IN LAKE EFFECT SNOWS OVER THE AREA FROM WEST TO EAST. THE CURRENT GRIDS ALREADY SHOW THIS SO WILL LEAVE THESE ALONE FOR NOW. ANOTHER WEAK SHORTWAVE WILL RELOCATE OVER THE FORECAST AREA ON THURSDAY AND STRETCH SOUTHWEST INTO IOWA. ANOTHER SHORTWAVE OVER SOUTHWESTERN SASKATCHEWAN WILL RELOCATE OVER SOUTHERN MANITOBA AND CENTRAL NORTH DAKOTA. THE SURFACE LOW WILL SHIFT NORTHEAST OUT OF KANSAS INTO NORTHWEST ILLINOIS. WRAP AROUND MOISTURE WILL SPREAD INTO THE SOUTHERN PART OF THE FORECAST AREA. ISENTROPIC ASCENT AND SHORTWAVE ENERGY WILL SQUEEZE SOME SNOW OUT OF THIS AIR MASS. NGM/NAM/GEM SHOW SCATTERED LIGHT PRECIPITATION...WHILE GFS SHOWS A QPF AROUND .11 INCH...WILL FAVOR THE MAJORITY ON THESE.THICKNESS FAVOR THIS PRECIPITATION WILL BE SNOW OVER THE AREA. THE GRIDS STILL LOOK REASONABLE. A MID LEVEL LOW WILL BE OVER HUDSON BAY THURSDAY NIGHT...WHILE WEAK SHORTWAVE SWEEPS THROUGH ONTARIO AND LAKE SUPERIOR. GFS/GEM DEVELOP A CLOSED LOW OVER SOUTH CENTRAL COLORADO. A SURFACE RIDGE WILL SPREAD OUT OF THE CENTRAL PLAINS AND REACH INTO THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY NIGHT. THIS WILL DRAW IN COOLER DRIER AIR ACROSS THE AREA AND WILL TEND TO REDUCE THE CHANCE OF SNOW FROM WEST TO EAST. AS THIS LOW MOVES TO THE EAST OF THE FORECAST AREA...COLD AIR WILL ADVECT IN. ANOTHER WEAK SHORTWAVE WILL SWEEP THROUGH THE FORECAST AREA ON FRIDAY. THE SURFACE HIGH WILL SPREAD INTO SOUTHEAST MINNESOTA...PRODUCING A WESTERLY FLOW ACROSS THE FORECAST AREA. THERE IS SOME WEAK COLD AIR ADVECTION OVER THE AREA. AN 850MB THERMAL TROUGH WILL MOVE INTO ONTARIO PRODUCING A WATER-850MB DELTA-T OF AROUND 15C OVER LAKE SUPERIOR. THIS WILL BE ENOUGH TO PRODUCE SOME LAKE EFFECT SNOWS ALONG THE NORTH SHORE. GRIDS STILL REFLECT THIS. ANOTHER SHORTWAVE WILL SWING ACROSS THE FORECAST AREA FRIDAY NIGHT. THE SURFACE RIDGE WILL REMAIN OVER THE AREA PRODUCING LIGHT NORTHEAST WINDS. THIS SHOULD PRODUCE ONLY WEAK LAKE EFFECT SNOWS OVER THE NORTHERN PART OF THE CWA. ANOTHER WEAK SHORTWAVE CAUGHT IN THE FLOW ACROSS THE NORTHERN CONUS WILL SWEEP THROUGH THE FORECAST AREA ON SATURDAY. THIS WILL PRODUCE A WEAK NORTHEAST WIND. A THERMAL TROUGH OVER THE AREA WILL LIKE MAKE FOR A DELTA-T OF 13C TO 17C. THIS WILL LIKELY KEEP SOME LAKE EFFECT SNOWS GOING OVER THE AREA. THE SHORTWAVE OVER LOWER MICHIGAN WILL RACE TO MAINE SATURDAY NIGHT WHILE THE SHORTWAVE OVER THE DAKOTAS SHIFTS INTO NORTHERN MINNESOTA. ANOTHER SHORTWAVE WILL SWEEP INTO SASKATCHEWAN...WHILE A RIDGE WILL PUSH ON TO CANADIAN PACIFIC COAST. THE SURFACE LOW WILL MOVE OUT NORTH DAKOTA INTO NORTHERN MINNESOTA...WHILE THE RIDGE OVER THE FORECAST AREA MOVES INTO EASTERN ONTARIO. CONDITIONS STILL APPEAR TO BE DRY...BUT WILL HAVE INCREASING CLOUD COVER. THE SHORTWAVE OVER MINNESOTA WILL MOVE INTO THE WESTERN U.P. ON SUNDAY...WHILE A CLOSED LOW DEVELOP OVER THE ARIZONA. THE SASKATCHEWAN SHORTWAVE WILL MOVE INTO NORTH DAKOTA AND MANITOBA. A WEAK CANADIAN COLD FRONT WILL MOVE INTO NORTHERN MINNESOTA AND CENTRAL ONTARIO. LOW LEVEL MOISTURE WILL BE QUITE LIMITED SO THERE WILL ONLY BE A CHANCE OF SOME SNOW AROUND THE FORECAST AREA. THE SHORTWAVE OVER MINNESOTA WILL RELOCATE OVER THE UPPER MICHIGAN ON MONDAY. HOWEVER...AT THE SURFACE A RIDGE WILL DO THE SAME...DRAWING STABLE AND LITTLE DRIER AIR OVER THE AREA. A WEAK SHORTWAVE AND A COLD FRONT WILL SWEEP QUICKLY THROUGH THE FORECAST AREA ON TUESDAY. A RIDGE WILL BE OVER THE FORECAST AREA ON WEDNESDAY...WHILE A SHORTWAVE AND LOW CENTER DEVELOPS OVER THE NORTHERN PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVY MIZ006 UNTIL 05Z. LAKE EFFECT SNOW ADVY MIZ007 UNTIL 11Z. && $$ ROLFSON (UPDATE) DLG (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 657 PM EST WED JAN 18 2006 .UPDATE... WILL ALLOW ADVY FOR NRN HOUGHTON AND KEWEENAW COUNTIES TO EXPIRE AS SCHEDULED AT 00Z. WITH 850MB THERMAL TROF NOW E OF WRN LAKE SUPERIOR PER 18Z GFS/18Z NAM/21Z RUC...LES HAS SHOWN A DEFINITE WEAKENING TREND PER RECENT OBS FROM KCMX AS WAA/FALLING INVERSION HEIGHTS ARE MAKING AN IMPACT. WINDS ARE ALSO DIMINISHING AT DISW4/ROAM4/PILM4... SO WINDS AND BLSN WILL ALSO BE DIMINISHING ON THE KEWEENAW VERY SOON. && .PREV DISCUSSION... ISSUED AT 331 PM EST THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR SNOW TONIGHT AND THURSDAY. WATER VAPOR IMAGERY AND RUC/NAM SHOWING A NEAR ZONAL FLOW BETWEEN A SHORTWAVE OVER THE EAST COAST AND ANOTHER OVER THE PACIFIC NORTHWEST. A WEAK SHORTWAVE IS OVER THE FORECAST AREA...EASTERN DAKOTAS AND IOWA...AND OVER WYOMING. SURFACE ANALYSIS INDICATE A LARGE LOW PRESSURE SYSTEM OVER QUEBEC AND THE EAST COAST...A RIDGE STRETCHING FROM MANITOBA SOUTH INTO CENTRAL TENNESSEE...AND ANOTHER DEEP LOW DEVELOPING OVER THE DAKOTAS. A WARM FRONT ACCOMPANYING THIS DAKOTA LOW EXTENDS SOUTHEAST INTO THE MIDDLE MISSISSIPPI RIVER VALLEY. ANOTHER LOW IS OVER CENTRAL SASKATCHEWAN. AN 850MB THERMAL TROUGH IS OVER ONTARIO PRODUCING A LAKE-850MB DELTA-T OF AROUND 17C. THIS IS PRODUCING A FEW LAKE EFFECT SNOW BANDS ACROSS THE FORECAST AREA. THE SHORTWAVE OVER THE FORECAST AREA WILL SHIFT INTO QUEBEC TONIGHT. THE SURFACE LOW WILL MOVE OUT OF THE NORTHERN PLAINS AND SWING TO THE SOUTH OF THE FORECAST AREA FORCING A RIDGE TO FORM ACROSS UPPER MICHIGAN. THE 850MB THERMAL TROUGH WILL RELOCATE OVER WESTERN QUEBEC OVERNIGHT...INDICATING WARM AIR ADVECTION AND A REDUCING IN LAKE EFFECT SNOWS OVER THE AREA FROM WEST TO EAST. THE CURRENT GRIDS ALREADY SHOW THIS SO WILL LEAVE THESE ALONE FOR NOW. ANOTHER WEAK SHORTWAVE WILL RELOCATE OVER THE FORECAST AREA ON THURSDAY AND STRETCH SOUTHWEST INTO IOWA. ANOTHER SHORTWAVE OVER SOUTHWESTERN SASKATCHEWAN WILL RELOCATE OVER SOUTHERN MANITOBA AND CENTRAL NORTH DAKOTA. THE SURFACE LOW WILL SHIFT NORTHEAST OUT OF KANSAS INTO NORTHWEST ILLINOIS. WRAP AROUND MOISTURE WILL SPREAD INTO THE SOUTHERN PART OF THE FORECAST AREA. ISENTROPIC ASCENT AND SHORTWAVE ENERGY WILL SQUEEZE SOME SNOW OUT OF THIS AIR MASS. NGM/NAM/GEM SHOW SCATTERED LIGHT PRECIPITATION...WHILE GFS SHOWS A QPF AROUND .11 INCH...WILL FAVOR THE MAJORITY ON THESE.THICKNESS FAVOR THIS PRECIPITATION WILL BE SNOW OVER THE AREA. THE GRIDS STILL LOOK REASONABLE. A MID LEVEL LOW WILL BE OVER HUDSON BAY THURSDAY NIGHT...WHILE WEAK SHORTWAVE SWEEPS THROUGH ONTARIO AND LAKE SUPERIOR. GFS/GEM DEVELOP A CLOSED LOW OVER SOUTH CENTRAL COLORADO. A SURFACE RIDGE WILL SPREAD OUT OF THE CENTRAL PLAINS AND REACH INTO THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY NIGHT. THIS WILL DRAW IN COOLER DRIER AIR ACROSS THE AREA AND WILL TEND TO REDUCE THE CHANCE OF SNOW FROM WEST TO EAST. AS THIS LOW MOVES TO THE EAST OF THE FORECAST AREA...COLD AIR WILL ADVECT IN. ANOTHER WEAK SHORTWAVE WILL SWEEP THROUGH THE FORECAST AREA ON FRIDAY. THE SURFACE HIGH WILL SPREAD INTO SOUTHEAST MINNESOTA...PRODUCING A WESTERLY FLOW ACROSS THE FORECAST AREA. THERE IS SOME WEAK COLD AIR ADVECTION OVER THE AREA. AN 850MB THERMAL TROUGH WILL MOVE INTO ONTARIO PRODUCING A WATER-850MB DELTA-T OF AROUND 15C OVER LAKE SUPERIOR. THIS WILL BE ENOUGH TO PRODUCE SOME LAKE EFFECT SNOWS ALONG THE NORTH SHORE. GRIDS STILL REFLECT THIS. ANOTHER SHORTWAVE WILL SWING ACROSS THE FORECAST AREA FRIDAY NIGHT. THE SURFACE RIDGE WILL REMAIN OVER THE AREA PRODUCING LIGHT NORTHEAST WINDS. THIS SHOULD PRODUCE ONLY WEAK LAKE EFFECT SNOWS OVER THE NORTHERN PART OF THE CWA. ANOTHER WEAK SHORTWAVE CAUGHT IN THE FLOW ACROSS THE NORTHERN CONUS WILL SWEEP THROUGH THE FORECAST AREA ON SATURDAY. THIS WILL PRODUCE A WEAK NORTHEAST WIND. A THERMAL TROUGH OVER THE AREA WILL LIKE MAKE FOR A DELTA-T OF 13C TO 17C. THIS WILL LIKELY KEEP SOME LAKE EFFECT SNOWS GOING OVER THE AREA. THE SHORTWAVE OVER LOWER MICHIGAN WILL RACE TO MAINE SATURDAY NIGHT WHILE THE SHORTWAVE OVER THE DAKOTAS SHIFTS INTO NORTHERN MINNESOTA. ANOTHER SHORTWAVE WILL SWEEP INTO SASKATCHEWAN...WHILE A RIDGE WILL PUSH ON TO CANADIAN PACIFIC COAST. THE SURFACE LOW WILL MOVE OUT NORTH DAKOTA INTO NORTHERN MINNESOTA...WHILE THE RIDGE OVER THE FORECAST AREA MOVES INTO EASTERN ONTARIO. CONDITIONS STILL APPEAR TO BE DRY...BUT WILL HAVE INCREASING CLOUD COVER. THE SHORTWAVE OVER MINNESOTA WILL MOVE INTO THE WESTERN U.P. ON SUNDAY...WHILE A CLOSED LOW DEVELOP OVER THE ARIZONA. THE SASKATCHEWAN SHORTWAVE WILL MOVE INTO NORTH DAKOTA AND MANITOBA. A WEAK CANADIAN COLD FRONT WILL MOVE INTO NORTHERN MINNESOTA AND CENTRAL ONTARIO. LOW LEVEL MOISTURE WILL BE QUITE LIMITED SO THERE WILL ONLY BE A CHANCE OF SOME SNOW AROUND THE FORECAST AREA. THE SHORTWAVE OVER MINNESOTA WILL RELOCATE OVER THE UPPER MICHIGAN ON MONDAY. HOWEVER...AT THE SURFACE A RIDGE WILL DO THE SAME...DRAWING STABLE AND LITTLE DRIER AIR OVER THE AREA. A WEAK SHORTWAVE AND A COLD FRONT WILL SWEEP QUICKLY THROUGH THE FORECAST AREA ON TUESDAY. A RIDGE WILL BE OVER THE FORECAST AREA ON WEDNESDAY...WHILE A SHORTWAVE AND LOW CENTER DEVELOPS OVER THE NORTHERN PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVY MIZ006-007 UNTIL 05Z. GALE WARNING E HALF OF LAKE SUPERIOR. && $$ ROLFSON (UPDATE) DLG (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 331 PM EST WED JAN 18 2006 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR SNOW TONIGHT AND THURSDAY. WATER VAPOR IMAGERY AND RUC/NAM SHOWING A NEAR ZONAL FLOW BETWEEN A SHORTWAVE OVER THE EAST COAST AND ANOTHER OVER THE PACIFIC NORTHWEST. A WEAK SHORTWAVE IS OVER THE FORECAST AREA...EASTERN DAKOTAS AND IOWA...AND OVER WYOMING. SURFACE ANALYSIS INDICATE A LARGE LOW PRESSURE SYSTEM OVER QUEBEC AND THE EAST COAST...A RIDGE STRETCHING FROM MANITOBA SOUTH INTO CENTRAL TENNESSEE...AND ANOTHER DEEP LOW DEVELOPING OVER THE DAKOTAS. A WARM FRONT ACCOMPANYING THIS DAKOTA LOW EXTENDS SOUTHEAST INTO THE MIDDLE MISSISSIPPI RIVER VALLEY. ANOTHER LOW IS OVER CENTRAL SASKATCHEWAN. AN 850MB THERMAL TROUGH IS OVER ONTARIO PRODUCING A LAKE-850MB DELTA-T OF AROUND 17C. THIS IS PRODUCING A FEW LAKE EFFECT SNOW BANDS ACROSS THE FORECAST AREA. THE SHORTWAVE OVER THE FORECAST AREA WILL SHIFT INTO QUEBEC TONIGHT. THE SURFACE LOW WILL MOVE OUT OF THE NORTHERN PLAINS AND SWING TO THE SOUTH OF THE FORECAST AREA FORCING A RIDGE TO FORM ACROSS UPPER MICHIGAN. THE 850MB THERMAL TROUGH WILL RELOCATE OVER WESTERN QUEBEC OVERNIGHT...INDICATING WARM AIR ADVECTION AND A REDUCING IN LAKE EFFECT SNOWS OVER THE AREA FROM WEST TO EAST. THE CURRENT GRIDS ALREADY SHOW THIS SO WILL LEAVE THESE ALONE FOR NOW. ANOTHER WEAK SHORTWAVE WILL RELOCATE OVER THE FORECAST AREA ON THURSDAY AND STRETCH SOUTHWEST INTO IOWA. ANOTHER SHORTWAVE OVER SOUTHWESTERN SASKATCHEWAN WILL RELOCATE OVER SOUTHERN MANITOBA AND CENTRAL NORTH DAKOTA. THE SURFACE LOW WILL SHIFT NORTHEAST OUT OF KANSAS INTO NORTHWEST ILLINOIS. WRAP AROUND MOISTURE WILL SPREAD INTO THE SOUTHERN PART OF THE FORECAST AREA. ISENTROPIC ASCENT AND SHORTWAVE ENERGY WILL SQUEEZE SOME SNOW OUT OF THIS AIR MASS. NGM/NAM/GEM SHOW SCATTERED LIGHT PRECIPITATION...WHILE GFS SHOWS A QPF AROUND .11 INCH...WILL FAVOR THE MAJORITY ON THESE.THICKNESS FAVOR THIS PRECIPITATION WILL BE SNOW OVER THE AREA. THE GRIDS STILL LOOK REASONABLE. A MID LEVEL LOW WILL BE OVER HUDSON BAY THURSDAY NIGHT...WHILE WEAK SHORTWAVE SWEEPS THROUGH ONTARIO AND LAKE SUPERIOR. GFS/GEM DEVELOP A CLOSED LOW OVER SOUTH CENTRAL COLORADO. A SURFACE RIDGE WILL SPREAD OUT OF THE CENTRAL PLAINS AND REACH INTO THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY NIGHT. THIS WILL DRAW IN COOLER DRIER AIR ACROSS THE AREA AND WILL TEND TO REDUCE THE CHANCE OF SNOW FROM WEST TO EAST. AS THIS LOW MOVES TO THE EAST OF THE FORECAST AREA...COLD AIR WILL ADVECT IN. ANOTHER WEAK SHORTWAVE WILL SWEEP THROUGH THE FORECAST AREA ON FRIDAY. THE SURFACE HIGH WILL SPREAD INTO SOUTHEAST MINNESOTA...PRODUCING A WESTERLY FLOW ACROSS THE FORECAST AREA. THERE IS SOME WEAK COLD AIR ADVECTION OVER THE AREA. AN 850MB THERMAL TROUGH WILL MOVE INTO ONTARIO PRODUCING A WATER-850MB DELTA-T OF AROUND 15C OVER LAKE SUPERIOR. THIS WILL BE ENOUGH TO PRODUCE SOME LAKE EFFECT SNOWS ALONG THE NORTH SHORE. GRIDS STILL REFLECT THIS. ANOTHER SHORTWAVE WILL SWING ACROSS THE FORECAST AREA FRIDAY NIGHT. THE SURFACE RIDGE WILL REMAIN OVER THE AREA PRODUCING LIGHT NORTHEAST WINDS. THIS SHOULD PRODUCE ONLY WEAK LAKE EFFECT SNOWS OVER THE NORTHERN PART OF THE CWA. ANOTHER WEAK SHORTWAVE CAUGHT IN THE FLOW ACROSS THE NORTHERN CONUS WILL SWEEP THROUGH THE FORECAST AREA ON SATURDAY. THIS WILL PRODUCE A WEAK NORTHEAST WIND. A THERMAL TROUGH OVER THE AREA WILL LIKE MAKE FOR A DELTA-T OF 13C TO 17C. THIS WILL LIKELY KEEP SOME LAKE EFFECT SNOWS GOING OVER THE AREA. THE SHORTWAVE OVER LOWER MICHIGAN WILL RACE TO MAINE SATURDAY NIGHT WHILE THE SHORTWAVE OVER THE DAKOTAS SHIFTS INTO NORTHERN MINNESOTA. ANOTHER SHORTWAVE WILL SWEEP INTO SASKATCHEWAN...WHILE A RIDGE WILL PUSH ON TO CANADIAN PACIFIC COAST. THE SURFACE LOW WILL MOVE OUT NORTH DAKOTA INTO NORTHERN MINNESOTA...WHILE THE RIDGE OVER THE FORECAST AREA MOVES INTO EASTERN ONTARIO. CONDITIONS STILL APPEAR TO BE DRY...BUT WILL HAVE INCREASING CLOUD COVER. THE SHORTWAVE OVER MINNESOTA WILL MOVE INTO THE WESTERN U.P. ON SUNDAY...WHILE A CLOSED LOW DEVELOP OVER THE ARIZONA. THE SASKATCHEWAN SHORTWAVE WILL MOVE INTO NORTH DAKOTA AND MANITOBA. A WEAK CANADIAN COLD FRONT WILL MOVE INTO NORTHERN MINNESOTA AND CENTRAL ONTARIO. LOW LEVEL MOISTURE WILL BE QUITE LIMITED SO THERE WILL ONLY BE A CHANCE OF SOME SNOW AROUND THE FORECAST AREA. THE SHORTWAVE OVER MINNESOTA WILL RELOCATE OVER THE UPPER MICHIGAN ON MONDAY. HOWEVER...AT THE SURFACE A RIDGE WILL DO THE SAME...DRAWING STABLE AND LITTLE DRIER AIR OVER THE AREA. A WEAK SHORTWAVE AND A COLD FRONT WILL SWEEP QUICKLY THROUGH THE FORECAST AREA ON TUESDAY. A RIDGE WILL BE OVER THE FORECAST AREA ON WEDNESDAY...WHILE A SHORTWAVE AND LOW CENTER DEVELOPS OVER THE NORTHERN PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1000 AM EST WED JAN 18 2006 .UPDATED... THE GRR 88D RADAR TRENDS SUGGEST THAT WHAT THE MODEL SOUNDINGS AND TAMDAR SHOWS IS TRUE. THAT IS...SNOW SHOWERS ACROSS THE COUNTY WARNING AREA...WILL CONTINUE THROUGH EARLY AFTERNOON. TAMDAR SOUNDING SHOW THE INVERSION LEVEL NEAR 800 MB AND THE TOP OF THE MOISTURE NEAR 750 MB. BOTH THE NAM AND RUC FORECAST SUGGEST THIS WILL CONTINUE TO BE THE CASE INTO THE AFTERNOON... THAT IS... WEST WINDS AROUND 25 KNOTS IN THE CLOUD BEARING LAYER WITH TEMPERATURES IN THE CLOUD NEAR BETWEEN -10C AND -13C. CLASSIC FOR SNOW FLAKE NUCLEATION. WHILE THE CLEARING LINE IS 1/2 WAY ACROSS LAKE MICHIGAN...GIVEN HOW COLD THE AIR UPSTREAM IS... I WILL KEEP SNOW SHOWERS IN THE FORECAST TILL MID AFTERNOON THEN DIMINISH TO FLURRIES BEFORE ENDING THIS EVENING. THAT IS THE CLEARING LINE WILL NOT MAKE IT ON SHORE TILL EARLY EVENING. ACCUMULATIONS SHOULD BE LIGHT... GENERALLY AN INCH OR LESS. TEMPERATURES WILL NOT RISE MUCH GIVEN ITS IN THE UPPER TEENS TO LOWER 20S ACROSS WI AT 15Z. TEMPERATURES COULD EVEN FALL A LITTLE BIT THIS AFTERNOON... MOSTLY THOUGH THEY WILL STAY IN THE 20S. && .GRR WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY NEARSHORE WATERS ST. JOSEPH TO MANISTEE THROUGH LATE TONIGHT. && $$ WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 955 PM CST WED JAN 18 2006 .DISCUSSION... MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES DUE TO WILD FLUCTUATIONS OVER WESTERN MO/EASTERN KS WHERE SOUTH WINDS HAVE PICKED UP OVER THE PAST 2 HOURS. HAVE ALSO RAISED LOW TEMPERATURES FROM STJ TO MKC. DESPITE THE VERY LOW DEWPOINTS IF THE WINDS STAY UP AROUND 10 KTS ALL NIGHT THEN THE CURRENT LOW TEMPERATURES WILL PROVE TO BE TOO LOW. CONFIDENCE NOT PARTICULARLY HIGH THAT WE WILL SEE SUSTAINED WINDS THAT HIGH. ALL IT TAKES IS AN HOUR OR TWO FOR WINDS TO DROP OFF TO LESS THAN 5 KTS AND THE TEMPERATURE WILL TAKE A NOSEDIVE. MJ && .PREV DISCUSSION... 355 PM... THE MAIN WEATHER CONCERN FOR THE NEXT FEW DAYS IS THE POTENTIAL FOR SIGNIFICANT SNOWS OVER NORTHERN MISSOURI FRIDAY INTO FRIDAY NIGHT. AN IMPRESSIVE COLD CORE LOW OVER COASTAL OREGON IS MOVING INLAND THIS AFTERNOON. IT IS TOUGH TO DETERMINE HOW THE 12Z MODELS INITIALIZED THIS SYSTEM SINCE THE CENTER WAS STILL WELL OVER THE OCEAN AT THE TIME THE MORNING RAOBS WERE LAUNCHED. RUN TO RUN CONTINUITY HAS BEEN PROBLEMATIC WITH THE GFS. THE 00Z RUN WAS MORE ENERGETIC THAN THE LATER 06Z AND 12Z RUNS. FOR THIS FORECAST...I HAVE DISCOUNTED THE FAST AND FLAT NAM IN FAVOR OF A GFS/UKMET COMPROMISE. THIS COMPROMISE SEEMS TO BE CLOSEST TO A MODEL CONSENSUS...WITH THE PROGRESSIVE NAM AND HIGHLY ENERGIZED CANADIAN MODELS ON OPPOSING ENDS OF THE SPECTRUM. GULF MOISTURE WILL BE SLOW TO RETURN TO THE CENTRAL UNITED STATES AHEAD OF THIS SYSTEM...OR ELSE THE POTENTIAL FOR FLOODING RAINS WOULD BE A CONCERN THURSDAY NIGHT INTO FRIDAY. BUT AS OF THIS AFTERNOON...SURFACE DEWPOINTS REMAINED IN THE TEENS AND TWENTIES OVER MUCH OF TEXAS. BUOYS OVER THE CENTRAL GULF ARE ONLY MEASURING DEWPOINTS IN THE 40S WITH A PREVAILING NORTH WIND. SO DESPITE STRONG WARM ADVECTION THURSDAY AND THURSDAY NIGHT...PRECIPITATION IS NOT EXPECTED TO DEVELOP UNTIL FRIDAY MORNING WHEN A STRONG INFLUX OF GULF MOISTURE INTERACTS WITH A STRENGTHENING FRONTAL BOUNDARY BISECTING MISSOURI. I HAVE CHANGED LITTLE FROM THE PREVIOUS FORECAST WHEN IT COMES TO THE RAIN SNOW LINE. EVAPORATIVE PROCESSES IN THE LOWEST TEN THOUSAND FEET OF THE FORECAST SOUNDING SUGGEST THAT LIQUID PRECIPITATION WILL CHANGE TO SNOW ALONG AND NORTH OF HIGHWAY 36 ON FRIDAY MORNING...AND SNOW SHOULD SURGE SOUTHWARD DURING THE AFTERNOON AS COLD AIR IS INGESTED INTO THE STORM. THE MOST SUBSTANTIAL ACCUMULATIONS APPEAR TO BE ALONG AN AXIS FROM SAINT JOSEPH TO CHILLICOTHE TO NORTH OF KIRKSVILLE...BUT FORECASTING ACCUMULATIONS REMAIN A LOW CONFIDENCE ENDEAVOR AT THIS POINT. ONCE THE UPPER LOW OVER OREGON CAN BE SAMPLED BETTER BY THE NORTH AMERICAN UPPER AIR NETWORK...THE MODELS SHOULD BE ABLE TO PINPOINT THE TRACK AND INTENSITY OF THIS STORM BETTER. KOCH && .AVIATION DISCUSSION... 1122 AM... LOW LEVEL WIND SHEAR HAS BEEN ADDED TO THE 18Z TAFS FOR EARLY EVENING. HEIGHTS ARE LOWERING OVER THE CENTRAL ROCKIES THIS AFTERNOON IN RESPONSE TO THE ADVANCING UPPER LOW MAKING LANDFALL ON THE COAST OF OREGON. A LEAD SHORTWAVE TROUGH IS EVIDENT ON WATER VAPOR IMAGERY NEAR THE FOUR CORNERS AT THIS HOUR. 16Z WIND PROFILERS OVER NORTHERN OKLAHOMA VALIDATE THE RUC AND NAM TRENDS THAT 2000FT WINDS WILL INCREASE TO AROUND 40KTS BETWEEN 00Z AND 04Z AS THE FOUR CORNERS SHORTWAVE TRAVERSES THE SOUTHERN ROCKIES. KOCH && .PREV DISCUSSION... 328 AM WED... ...POTENT WINTER STORM TO IMPACT NORTHERN MISSOURI LATE FRIDAY... SURFACE HIGH PRESSURE WAS PASSING THROUGH THE REGION EARLY THIS MORNING WITH CLEAR SKIES AND SEASONABLY CHILLY TEMPERATURES. MEANWHILE...UPSTREAM CIRRUS WAS PLENTIFUL AND BEGINNING SPILL OVER THE CONTINENTAL DIVIDE IN ASSOCIATION WITH A WEAK SHORTWAVE TROUGH THAT WILL PASS NORTH OF THE AREA TOMORROW. UNSEASONABLY MILD TEMPERATURES WILL BE THE MAIN STORY FOR THE NEXT 48 HOURS AS STRONG MID LEVEL ZONAL FLOW PROMOTES DOWNSLOPE WARMING ACROSS THE PLAINS. FOR TODAY...THE WARMUP WILL BE SUPPRESSED TO A SMALL DEGREE BY INCREASING HIGH CLOUD COVER FROM THE NORTHWEST AND THE PRESENCE OF WEAK SOUTHERLY LOW LEVEL FLOW THAT WILL NOT BEGIN TO STRENGTHEN UNTIL LATE. STILL...ALL BUT FAR NE MO SHOULD BE INTO THE 50S THIS AFTERNOON. A SIMILAR DAY IS EXPECTED ON THURSDAY...WITH THE THERMAL GRADIENT ALIGNED NORTHWEST TO SOUTHEAST AS THE INITIAL LEAD WAVE MENTIONED ABOVE DROPS A SUBTLE SURFACE BOUNDARY INTO THE AREA. AGAIN LOOKING FOR READINGS SOME 15 TO 20 DEGREES ABOVE NORMAL. THE MAIN EVENT WILL BEGIN TO UNFOLD THURSDAY NIGHT AS A POTENT STORM SYSTEM CURRENTLY ORGANIZING OFF THE OREGON COAST DIGS INTO THE SOUTHERN ROCKIES. WATER VAPOR IMAGERY SHOWS A MOIST SUBTROPICAL JET PLUME NOSING INTO SOUTHERN CALIFORNIA EARLY THIS MORNING. AS UPSTREAM JET ENERGY ARRIVES...THIS PLUME WILL BEGIN TO SHARPEN AND BUCKLE...RESULTING IN DEEP NORTHWARD MOISTURE TRANSPORT. RAPID SURFACE CYCLOGENESIS WILL OCCUR OVER THE TEXAS PANHANDLE...WITH THE SURFACE LOW THEN EXPECTED TO TRACK ALONG AN INCREASINGLY SHARP BAROCLINIC ZONE ALONG THE INTERSTATE 44 CORRIDOR. NORTH OF THE SURFACE BOUNDARY...A SYNOPTICALLY FORCED LOW LEVEL JET WILL DELIVER THE INITIAL MEANS FOR LARGE SCALE ASCENT ON FRIDAY...WITH STRONG LOW LEVEL WARM/MOIST ADVECTION BEING FORCED ISENTROPICALLY THROUGH A SHARPENING FRONTAL ZONE. THIS WILL ACT UPON A PRE-EXISTING LAYER OF WEAK-MODERATE POTENTIAL INSTABILITY ABOVE 850MB. ELEVATED THUNDERSTORMS COULD BECOME FAIRLY WIDESPREAD ON FRIDAY AND HAVE BROUGHT THEM FURTHER NORTH PER GFS SOUNDINGS. AS THE SURFACE LOW REACHES SOUTHWEST MISSOURI FRIDAY EVENING... STRENGTHENING NORTHERLY AGEOSTROPHIC FLOW WILL PROMOTE A STEADY COOLING OF THE BOUNDARY LAYER...AIDED FURTHER BY DIABATIC COOLING PROCESSES AS PRECIPITATION CONTINUES AMIDST STRONG ISENTROPIC ASCENT AND MID LEVEL FRONTOGENESIS. AS A RESULT...PRECIPITATION SHOULD UNDERGO A STEADY TRANSITION FROM RAIN TO SNOW FROM NORTHWEST TO SOUTHEAST FRIDAY NIGHT AS LOW LEVEL FLOW BACKS. THE UPPER LOW WILL THEN ATTEMPT TO CLOSE OFF TOWARD 12Z SATURDAY...DRAWING THE WARM CONVEYOR BELT WESTWARD INTO A DEVELOPING TROWAL REGION FOR ENHANCED ASCENT ALONG THE MO/IA BORDER. A RESULTANT NARROW SWATH OF HEAVY WET SNOW WILL BE MAXIMIZED WHERE WARM ADVECTION AND WRAPAROUND SNOWS ARE CO-LOCATED. THE GFS HAS BEEN VERY CONSISTENT WITH PAINTING THIS AREA ACROSS FAR NORTHERN MO...SOMEWHERE ALONG AND NORTH OF A ST. JOSEPH TO CHILLICOTHE TO KIRKSVILLE LINE. ALTHOUGH THIS PROGRESSIVE SYSTEM WILL HAVE TO BATTLE AN INITIALLY MILD BOUNDARY LAYER...THE SYNOPTIC TRACK CERTAINLY FAVORS SIGNIFICANT ACCUMULATIONS ACROSS NORTHERN MISSOURI. THIS ISNT A CLOSED BOOK BY ANY MEANS...BUT THE TRENDS REMAIN VERY CONSISTENT. WILL CONTINUE TO HIT THIS IN THE HWO AND A WATCH MAY BE REQUIRED IN THE NEXT 24-36 HOURS. PRECIPITATION WILL EXIT NORTHEAST MO BY MIDDAY SATURDAY AND HAVE TRENDED TEMPS DOWNWARD SATURDAY AND ESPECIALLY SATURDAY NIGHT AS HIGH PRESSURE SETTLES OVER THE PROJECTED SNOWPACK. BOOKBINDER && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 355 PM CST WED JAN 18 2006 THE MAIN WEATHER CONCERN FOR THE NEXT FEW DAYS IS THE POTENTIAL FOR SIGNIFICANT SNOWS OVER NORTHERN MISSOURI FRIDAY INTO FRIDAY NIGHT. AN IMPRESSIVE COLD CORE LOW OVER COASTAL OREGON IS MOVING INLAND THIS AFTERNOON. IT IS TOUGH TO DETERMINE HOW THE 12Z MODELS INITIALIZED THIS SYSTEM SINCE THE CENTER WAS STILL WELL OVER THE OCEAN AT THE TIME THE MORNING RAOBS WERE LAUNCHED. RUN TO RUN CONTINUITY HAS BEEN PROBLEMATIC WITH THE GFS. THE 00Z RUN WAS MORE ENERGETIC THAN THE LATER 06Z AND 12Z RUNS. FOR THIS FORECAST...I HAVE DISCOUNTED THE FAST AND FLAT NAM IN FAVOR OF A GFS/UKMET COMPROMISE. THIS COMPROMISE SEEMS TO BE CLOSEST TO A MODEL CONSENSUS...WITH THE PROGRESSIVE NAM AND HIGHLY ENERGIZED CANADIAN MODELS ON OPPOSING ENDS OF THE SPECTRUM. GULF MOISTURE WILL BE SLOW TO RETURN TO THE CENTRAL UNITED STATES AHEAD OF THIS SYSTEM...OR ELSE THE POTENTIAL FOR FLOODING RAINS WOULD BE A CONCERN THURSDAY NIGHT INTO FRIDAY. BUT AS OF THIS AFTERNOON...SURFACE DEWPOINTS REMAINED IN THE TEENS AND TWENTIES OVER MUCH OF TEXAS. BUOYS OVER THE CENTRAL GULF ARE ONLY MEASURING DEWPOINTS IN THE 40S WITH A PREVAILING NORTH WIND. SO DESPITE STRONG WARM ADVECTION THURSDAY AND THURSDAY NIGHT...PRECIPITATION IS NOT EXPECTED TO DEVELOP UNTIL FRIDAY MORNING WHEN A STRONG INFLUX OF GULF MOISTURE INTERACTS WITH A STRENGTHENING FRONTAL BOUNDARY BISECTING MISSOURI. I HAVE CHANGED LITTLE FROM THE PREVIOUS FORECAST WHEN IT COMES TO THE RAIN SNOW LINE. EVAPORATIVE PROCESSES IN THE LOWEST TEN THOUSAND FEET OF THE FORECAST SOUNDING SUGGEST THAT LIQUID PRECIPITATION WILL CHANGE TO SNOW ALONG AND NORTH OF HIGHWAY 36 ON FRIDAY MORNING...AND SNOW SHOULD SURGE SOUTHWARD DURING THE AFTERNOON AS COLD AIR IS INGESTED INTO THE STORM. THE MOST SUBSTANTIAL ACCUMULATIONS APPEAR TO BE ALONG AN AXIS FROM SAINT JOSEPH TO CHILLICOTHE TO NORTH OF KIRKSVILLE...BUT FORECASTING ACCUMULATIONS REMAIN A LOW CONFIDENCE ENDEAVOR AT THIS POINT. ONCE THE UPPER LOW OVER OREGON CAN BE SAMPLED BETTER BY THE NORTH AMERICAN UPPER AIR NETWORK...THE MODELS SHOULD BE ABLE TO PINPOINT THE TRACK AND INTENSITY OF THIS STORM BETTER. KOCH && .AVIATION DISCUSSION... 1122 AM... LOW LEVEL WIND SHEAR HAS BEEN ADDED TO THE 18Z TAFS FOR EARLY EVENING. HEIGHTS ARE LOWERING OVER THE CENTRAL ROCKIES THIS AFTERNOON IN RESPONSE TO THE ADVANCING UPPER LOW MAKING LANDFALL ON THE COAST OF OREGON. A LEAD SHORTWAVE TROUGH IS EVIDENT ON WATER VAPOR IMAGERY NEAR THE FOUR CORNERS AT THIS HOUR. 16Z WIND PROFILERS OVER NORTHERN OKLAHOMA VALIDATE THE RUC AND NAM TRENDS THAT 2000FT WINDS WILL INCREASE TO AROUND 40KTS BETWEEN 00Z AND 04Z AS THE FOUR CORNERS SHORTWAVE TRAVERSES THE SOUTHERN ROCKIES. KOCH && .PREV DISCUSSION... 328 AM WED... ...POTENT WINTER STORM TO IMPACT NORTHERN MISSOURI LATE FRIDAY... SURFACE HIGH PRESSURE WAS PASSING THROUGH THE REGION EARLY THIS MORNING WITH CLEAR SKIES AND SEASONABLY CHILLY TEMPERATURES. MEANWHILE...UPSTREAM CIRRUS WAS PLENTIFUL AND BEGINNING SPILL OVER THE CONTINENTAL DIVIDE IN ASSOCIATION WITH A WEAK SHORTWAVE TROUGH THAT WILL PASS NORTH OF THE AREA TOMORROW. UNSEASONABLY MILD TEMPERATURES WILL BE THE MAIN STORY FOR THE NEXT 48 HOURS AS STRONG MID LEVEL ZONAL FLOW PROMOTES DOWNSLOPE WARMING ACROSS THE PLAINS. FOR TODAY...THE WARMUP WILL BE SUPPRESSED TO A SMALL DEGREE BY INCREASING HIGH CLOUD COVER FROM THE NORTHWEST AND THE PRESENCE OF WEAK SOUTHERLY LOW LEVEL FLOW THAT WILL NOT BEGIN TO STRENGTHEN UNTIL LATE. STILL...ALL BUT FAR NE MO SHOULD BE INTO THE 50S THIS AFTERNOON. A SIMILAR DAY IS EXPECTED ON THURSDAY...WITH THE THERMAL GRADIENT ALIGNED NORTHWEST TO SOUTHEAST AS THE INITIAL LEAD WAVE MENTIONED ABOVE DROPS A SUBTLE SURFACE BOUNDARY INTO THE AREA. AGAIN LOOKING FOR READINGS SOME 15 TO 20 DEGREES ABOVE NORMAL. THE MAIN EVENT WILL BEGIN TO UNFOLD THURSDAY NIGHT AS A POTENT STORM SYSTEM CURRENTLY ORGANIZING OFF THE OREGON COAST DIGS INTO THE SOUTHERN ROCKIES. WATER VAPOR IMAGERY SHOWS A MOIST SUBTROPICAL JET PLUME NOSING INTO SOUTHERN CALIFORNIA EARLY THIS MORNING. AS UPSTREAM JET ENERGY ARRIVES...THIS PLUME WILL BEGIN TO SHARPEN AND BUCKLE...RESULTING IN DEEP NORTHWARD MOISTURE TRANSPORT. RAPID SURFACE CYCLOGENESIS WILL OCCUR OVER THE TEXAS PANHANDLE...WITH THE SURFACE LOW THEN EXPECTED TO TRACK ALONG AN INCREASINGLY SHARP BAROCLINIC ZONE ALONG THE INTERSTATE 44 CORRIDOR. NORTH OF THE SURFACE BOUNDARY...A SYNOPTICALLY FORCED LOW LEVEL JET WILL DELIVER THE INITIAL MEANS FOR LARGE SCALE ASCENT ON FRIDAY...WITH STRONG LOW LEVEL WARM/MOIST ADVECTION BEING FORCED ISENTROPICALLY THROUGH A SHARPENING FRONTAL ZONE. THIS WILL ACT UPON A PRE-EXISTING LAYER OF WEAK-MODERATE POTENTIAL INSTABILITY ABOVE 850MB. ELEVATED THUNDERSTORMS COULD BECOME FAIRLY WIDESPREAD ON FRIDAY AND HAVE BROUGHT THEM FURTHER NORTH PER GFS SOUNDINGS. AS THE SURFACE LOW REACHES SOUTHWEST MISSOURI FRIDAY EVENING... STRENGTHENING NORTHERLY AGEOSTROPHIC FLOW WILL PROMOTE A STEADY COOLING OF THE BOUNDARY LAYER...AIDED FURTHER BY DIABATIC COOLING PROCESSES AS PRECIPITATION CONTINUES AMIDST STRONG ISENTROPIC ASCENT AND MID LEVEL FRONTOGENESIS. AS A RESULT...PRECIPITATION SHOULD UNDERGO A STEADY TRANSITION FROM RAIN TO SNOW FROM NORTHWEST TO SOUTHEAST FRIDAY NIGHT AS LOW LEVEL FLOW BACKS. THE UPPER LOW WILL THEN ATTEMPT TO CLOSE OFF TOWARD 12Z SATURDAY...DRAWING THE WARM CONVEYOR BELT WESTWARD INTO A DEVELOPING TROWAL REGION FOR ENHANCED ASCENT ALONG THE MO/IA BORDER. A RESULTANT NARROW SWATH OF HEAVY WET SNOW WILL BE MAXIMIZED WHERE WARM ADVECTION AND WRAPAROUND SNOWS ARE CO-LOCATED. THE GFS HAS BEEN VERY CONSISTENT WITH PAINTING THIS AREA ACROSS FAR NORTHERN MO...SOMEWHERE ALONG AND NORTH OF A ST. JOSEPH TO CHILLICOTHE TO KIRKSVILLE LINE. ALTHOUGH THIS PROGRESSIVE SYSTEM WILL HAVE TO BATTLE AN INITIALLY MILD BOUNDARY LAYER...THE SYNOPTIC TRACK CERTAINLY FAVORS SIGNIFICANT ACCUMULATIONS ACROSS NORTHERN MISSOURI. THIS ISNT A CLOSED BOOK BY ANY MEANS...BUT THE TRENDS REMAIN VERY CONSISTENT. WILL CONTINUE TO HIT THIS IN THE HWO AND A WATCH MAY BE REQUIRED IN THE NEXT 24-36 HOURS. PRECIPITATION WILL EXIT NORTHEAST MO BY MIDDAY SATURDAY AND HAVE TRENDED TEMPS DOWNWARD SATURDAY AND ESPECIALLY SATURDAY NIGHT AS HIGH PRESSURE SETTLES OVER THE PROJECTED SNOWPACK. BOOKBINDER && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 1122 AM CST WED JAN 18 2006 .AVIATION DISCUSSION... LOW LEVEL WIND SHEAR HAS BEEN ADDED TO THE 18Z TAFS FOR EARLY EVENING. HEIGHTS ARE LOWERING OVER THE CENTRAL ROCKIES THIS AFTERNOON IN RESPONSE TO THE ADVANCING UPPER LOW MAKING LANDFALL ON THE COAST OF OREGON. A LEAD SHORTWAVE TROUGH IS EVIDENT ON WATER VAPOR IMAGERY NEAR THE FOUR CORNERS AT THIS HOUR. 16Z WIND PROFILERS OVER NORTHERN OKLAHOMA VALIDATE THE RUC AND NAM TRENDS THAT 2000FT WINDS WILL INCREASE TO AROUND 40KTS BETWEEN 00Z AND 04Z AS THE FOUR CORNERS SHORTWAVE TRAVERSES THE SOUTHERN ROCKIES. KOCH && .PREV DISCUSSION... 328 AM WED... ...POTENT WINTER STORM TO IMPACT NORTHERN MISSOURI LATE FRIDAY... SURFACE HIGH PRESSURE WAS PASSING THROUGH THE REGION EARLY THIS MORNING WITH CLEAR SKIES AND SEASONABLY CHILLY TEMPERATURES. MEANWHILE...UPSTREAM CIRRUS WAS PLENTIFUL AND BEGINNING SPILL OVER THE CONTINENTAL DIVIDE IN ASSOCIATION WITH A WEAK SHORTWAVE TROUGH THAT WILL PASS NORTH OF THE AREA TOMORROW. UNSEASONABLY MILD TEMPERATURES WILL BE THE MAIN STORY FOR THE NEXT 48 HOURS AS STRONG MID LEVEL ZONAL FLOW PROMOTES DOWNSLOPE WARMING ACROSS THE PLAINS. FOR TODAY...THE WARMUP WILL BE SUPPRESSED TO A SMALL DEGREE BY INCREASING HIGH CLOUD COVER FROM THE NORTHWEST AND THE PRESENCE OF WEAK SOUTHERLY LOW LEVEL FLOW THAT WILL NOT BEGIN TO STRENGTHEN UNTIL LATE. STILL...ALL BUT FAR NE MO SHOULD BE INTO THE 50S THIS AFTERNOON. A SIMILAR DAY IS EXPECTED ON THURSDAY...WITH THE THERMAL GRADIENT ALIGNED NORTHWEST TO SOUTHEAST AS THE INITIAL LEAD WAVE MENTIONED ABOVE DROPS A SUBTLE SURFACE BOUNDARY INTO THE AREA. AGAIN LOOKING FOR READINGS SOME 15 TO 20 DEGREES ABOVE NORMAL. THE MAIN EVENT WILL BEGIN TO UNFOLD THURSDAY NIGHT AS A POTENT STORM SYSTEM CURRENTLY ORGANIZING OFF THE OREGON COAST DIGS INTO THE SOUTHERN ROCKIES. WATER VAPOR IMAGERY SHOWS A MOIST SUBTROPICAL JET PLUME NOSING INTO SOUTHERN CALIFORNIA EARLY THIS MORNING. AS UPSTREAM JET ENERGY ARRIVES...THIS PLUME WILL BEGIN TO SHARPEN AND BUCKLE...RESULTING IN DEEP NORTHWARD MOISTURE TRANSPORT. RAPID SURFACE CYCLOGENESIS WILL OCCUR OVER THE TEXAS PANHANDLE...WITH THE SURFACE LOW THEN EXPECTED TO TRACK ALONG AN INCREASINGLY SHARP BAROCLINIC ZONE ALONG THE INTERSTATE 44 CORRIDOR. NORTH OF THE SURFACE BOUNDARY...A SYNOPTICALLY FORCED LOW LEVEL JET WILL DELIVER THE INITIAL MEANS FOR LARGE SCALE ASCENT ON FRIDAY...WITH STRONG LOW LEVEL WARM/MOIST ADVECTION BEING FORCED ISENTROPICALLY THROUGH A SHARPENING FRONTAL ZONE. THIS WILL ACT UPON A PRE-EXISTING LAYER OF WEAK-MODERATE POTENTIAL INSTABILITY ABOVE 850MB. ELEVATED THUNDERSTORMS COULD BECOME FAIRLY WIDESPREAD ON FRIDAY AND HAVE BROUGHT THEM FURTHER NORTH PER GFS SOUNDINGS. AS THE SURFACE LOW REACHES SOUTHWEST MISSOURI FRIDAY EVENING... STRENGTHENING NORTHERLY AGEOSTROPHIC FLOW WILL PROMOTE A STEADY COOLING OF THE BOUNDARY LAYER...AIDED FURTHER BY DIABATIC COOLING PROCESSES AS PRECIPITATION CONTINUES AMIDST STRONG ISENTROPIC ASCENT AND MID LEVEL FRONTOGENESIS. AS A RESULT...PRECIPITATION SHOULD UNDERGO A STEADY TRANSITION FROM RAIN TO SNOW FROM NORTHWEST TO SOUTHEAST FRIDAY NIGHT AS LOW LEVEL FLOW BACKS. THE UPPER LOW WILL THEN ATTEMPT TO CLOSE OFF TOWARD 12Z SATURDAY...DRAWING THE WARM CONVEYOR BELT WESTWARD INTO A DEVELOPING TROWAL REGION FOR ENHANCED ASCENT ALONG THE MO/IA BORDER. A RESULTANT NARROW SWATH OF HEAVY WET SNOW WILL BE MAXIMIZED WHERE WARM ADVECTION AND WRAPAROUND SNOWS ARE CO-LOCATED. THE GFS HAS BEEN VERY CONSISTENT WITH PAINTING THIS AREA ACROSS FAR NORTHERN MO...SOMEWHERE ALONG AND NORTH OF A ST. JOSEPH TO CHILLICOTHE TO KIRKSVILLE LINE. ALTHOUGH THIS PROGRESSIVE SYSTEM WILL HAVE TO BATTLE AN INITIALLY MILD BOUNDARY LAYER...THE SYNOPTIC TRACK CERTAINLY FAVORS SIGNIFICANT ACCUMULATIONS ACROSS NORTHERN MISSOURI. THIS ISNT A CLOSED BOOK BY ANY MEANS...BUT THE TRENDS REMAIN VERY CONSISTENT. WILL CONTINUE TO HIT THIS IN THE HWO AND A WATCH MAY BE REQUIRED IN THE NEXT 24-36 HOURS. PRECIPITATION WILL EXIT NORTHEAST MO BY MIDDAY SATURDAY AND HAVE TRENDED TEMPS DOWNWARD SATURDAY AND ESPECIALLY SATURDAY NIGHT AS HIGH PRESSURE SETTLES OVER THE PROJECTED SNOWPACK. BOOKBINDER && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 930 AM CST WED JAN 18 2006 FORECAST CHALLENGE CONCERNS CLOUD TRENDS AND TEMPERATURES. PERSISTENT BAND OF MVFR CIGS SHOWING SLIGHT EROSION OVER FAR SW FA WHERE RUC SHOWING LEAST AMOUNT OF LOW LEVEL RH. UPSTREAM SHORTWAVE SPREADING VFR CIGS EASTWARD THROUGH CENTRAL DAKOTAS. SO WHILE SOME BREAKS POSSIBLE ACROSS SOUTH THIS AM FEEL CLOUDS TO SPREAD BACK IN. FARTHER NORTH UNDER DEEPER LAYERERD RH AND WEAK MIXING EXPECT CLOUDS TO HOLD. AS A RESULT EXPECT LITTLE OVERALL CHANGE WITH TEMPERATURES. FLURRIES CONFINED ALONG AND EAST OF SURFACE RIDGE AXIS SO WILL MAINTAIN FLURRIES ACCORDINGLY INTO THIS AFTERNOON. CHANGES TO UPDATE WILL BE MINOR. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 912 AM EST WED JAN 18 2006 .SHORT TERM (REST OF TODAY)... QUICK UPDATE TO ZONES TO CLEAN UP MORNING WORDING. EXPECT WINDS TO REMAIN ON THE STRONG SIDE THROUGH EARLY AFTERNOON. THEN THE GRADIENT SHOULD WEAKEN LATER TODAY ALLOWING WINDS TO DECREASE LATE THIS AFTERNOON. && .PREVIOUS DISCUSSION... (ISSUED 228 AM EST WED JAN 18 2006) SHORT TERM (TODAY THROUGH FRIDAY)... CURRENT RADAR SHOWING SHOWERS MOVING ACROSS MIDLANDS WITH THE BACK EDGE OF PRECIPITATION IN THE PIEDMONT. LATEST 06Z RUC MODEL IN AGREEMENT WITH 00Z MODELS INDICATING PRECIPITATION WILL BE EAST OF THE CWA BY 12Z...SO WILL GO WITH A DRY FORECAST FOR TODAY. SOME MORNING CLOUDS EXPECTED...MAINLY NORTH OF CAE WITH BOUNDARY LAYER REMAINING QUITE MOIST...DRY AIR SPREADING NORTHEAST FROM ALABAMA/GEORGIA THIS MORNING. MOST AREAS SHOULD BE MOSTLY SUNNY BY LATE MORNING/EARLY AFTERNOON. BUFKIT SOUNDING/VAD WIND PROFILES SUGGEST GOOD MIXING TODAY WITH STRONG DOWNWARD VERTICAL MOTION. COLD AIR ADVECTION THROUGH EARLY AFTERNOON...THEN WEAK WARM ADVECTION DEVELOPS. WINDS SHOULD BE 20 TO 30 MPH WITH GUSTS TO 40 THROUGH MID AFTERNOON...SO CURRENT LAKE WIND ADVISORY APPROPRIATE. TEMPERATURE FORECAST...20 DEGREES COOLER THAN YESTERDAY. WINDS WILL DIMINISH EARLY THIS EVENING AS SURFACE RIDGE OVER SOUTH GEORGIA. SOME HIGH CLOUDS POSSIBLE OVERNIGHT WITH WEAK SHORT WAVES MOVING EAST OVER THE AREA IN FAST FLOW ALOFT...BUT MOSTLY CLEAR SEEMS OK. RADIATION SCHEME A LITTLE COOLER THAN MOS CONSENSUS...BUT WITH A FEW CLOUDS AND RIDGE SOUTH OF THE AREA WILL GO ABOVE LOCAL RADIATION VALUES ESPECIALLY IN THE CENTRAL AND NORTH MIDLANDS. RIDGE OFFSHORE THURSDAY SO WARM UP BEGINS. MOS CONSENSUS THROUGH FRIDAY. MODELS SHOW MOISTURE ADVECTION FRIDAY INTO THE REGION AHEAD OF NEXT SYSTEM...SO A FEW MORE CLOUDS EXPECTED. LONG TERM (FRIDAY NIGHT THROUGH TUESDAY)... NO CHANGES TO EXTENDED PERIOD. AVIATION... SHOWERS AND MVFR CONDITIONS ASSOCIATED WITH THE COLD FRONT WILL MOVE EAST OF THE TERMINALS EARLY THIS MORNING. THE RUC INDICATES VFR CONDITION SHOULD BEGIN AROUND 13Z AND THIS DRYING SHOULD CONTINUE DURING THE REST OF THE PERIOD. IT WILL REMAIN BREEZY. USED THE MAV WIND GUIDANCE. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 315 PM CST WED JAN 18 2006 .SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT CONCERNS FOR THE SHORT TERM CENTER AROUND PRECIPITATION CHANCES TONIGHT INTO EARLY THURSDAY. CURRENTLY HAVE AN UPPER WAVE PUSHING EAST OUT OF EASTERN MT/WY...WITH AN AREA OF SFC LOW PRESSURE SITUATED FROM EASTERN MT SOUTHEASTWARD INTO WESTERN SOUTH DAKOTA. CURRENTLY HAVE SOME VERY LIGHT SNOW SHOWERS ALONG THE BORDER OF ND/SD TO THE WEST OF ABERDEEN PUSHING EASTWARD. THIS AREA OF PRECIPITATION IS ASSOCIATED WITH A WARM FRONT SLOWLY PUSHING EAST...THAT WILL BECOME HUNG UP ACROSS THE CWA THIS EVENING. WARM FRONT BEGINS TO PUSH BACK TO THE SOUTH AS THE SFC TROUGH BEGINS TO PUSH EAST AND CAA BEGINS. RIGHT NOW MODELS IN SOME DISAGREEMENT OVER HOW TO HANDLE THIS SYSTEM AS IT MOVES THROUGH TONIGHT...WITH THE GFS LOOKING THE MOST CONSISTENT FROM PREVIOUS RUNS. THEREFORE HAVE USED THE GFS FOR THIS FORECAST PACKAGE...ALTHOUGH FEEL IT MAY BE A BIT OVERDONE. ABR SOUNDING EARLY TODAY INDICATED A SIGNIFICANT AMOUNT OF DRY AIR ALOFT...AND EXPECT THAT TO INHIBIT PRECIPITATION CHANCES SOMEWHAT ACROSS THE CWA TONIGHT. BETTER PUSH OF MOISTURE INTO THE CWA LATE TONIGHT...BUT BY THEN BEST FORCING WILL BE SITUATED MORE TO THE EAST. THEREFORE LEFT POPS IN THE SLIGHT CHANCE TO CHANCE CATEGORY ACROSS MOST AREAS...WITH THE BEST CHANCE FOR PRECIPITATION ACROSS THE NORTHEAST CORNER LATER THIS EVENING. BUFKIT AND RUC SOUNDINGS INDICATE TEMPS ABOVE FREEZING IN THE LOWER LEVELS ACROSS THE SOUTHERN HALF OF THE CWA THIS EVENING...WITH MOSTLY NEAR FREEZING OR BELOW TEMPERATURES ACROSS THE NORTHERN HALF OF THE CWA. THEREFORE WENT WITH SNOW WORDING ACROSS THE NORTH...AND DRIZZLE OR FREEZING DRIZZLE ACROSS THE SOUTHERN HALF OF THE CWA THIS EVENING. THEN SHOULD SEE ANY PRECIPITATION LATER TONIGHT FALL AS SNOW AS THE COLDER AIR SINKS INTO THE AREA. KEPT QPF AMOUNTS VERY LIGHT...AS AM NOT REAL IMPRESSED WITH THIS WAVE. EXPECT ONLY TRACE AMOUNTS TO A FEW HUNDREDTHS OF PRECIPITATION AT MOST SITES. CLOUDS ARE CURRENTLY COVERING THE NORTH/EASTERN CWA...WITH SUNNY SKIES ACROSS THE SOUTH. EXPECT CLOUDS TO INCREASE ACROSS THE CWA TONIGHT AS THE WAVE PUSHES EAST...WITH CLOUDS STICKING AROUND THROUGH MUCH OF THURSDAY. ANOTHER WEAK WAVE TO PUSH ACROSS THE NORTHEASTERN ZONES FRIDAY MORNING...BUT TIME HEIGHT SECTIONS LOOK REALLY DRY WITH THIS WAVE...SO LEFT THE PERIOD DRY. OTHERWISE UPPER LEVEL FLOW REMAINS OUT OF THE WEST/NORTHWEST THROUGH THE REMAINDER OF THE SHORT TERM. MODELS CONTINUE TO SHOW WEAK WAVES TRAVELING THROUGH THE REGION INTO THE WEEKEND...BUT JET STREAM SHIFTS TO THE NORTH A BIT WITH MOST OF THE WAVES MOVING ACROSS NORTH DAKOTA/SOUTHERN CANADA. .LONG TERM...SUNDAY THROUGH WEDNESDAY DOES STILL APPEAR THAT A MID LEVEL RIDGE WILL BUILD ACROSS THE WESTERN CONUS NORTH OF NEARLY CUTOFF ENERGY OVER THE SOUTHWESTERN CONUS. THIS SHOULD STILL SPELL A PERIOD OF RELATIVELY INACTIVE WEATHER OVER THE COUNTY WARNING AREA. BY LATE IN THE PERIOD...THE LATEST GFS RUN IS QUITE EAGER TO FLATTEN WESTERN RIDGE AND BOOT ENERGY NORTHEAST INTO THE CENTRAL PLAINS. THIS MIGHT BE A LITTLE PREMATURE BASED ON OTHER LONG RANGE MODELS. THUS...FOR NOW WILL MAINTAIN DRY FORECAST. TEMPERATURES ONLY MODIFIED SLIGHTLY FROM PREVIOUS GRIDS. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ ALBRECHT/TDK sd AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 548 AM MST WED JAN 18 2006 UPDATED FOR AVIATION PORTION OF THE DISCUSSION .DISCUSSION...CURRENT SURFACE MAP HAS TROF OF LOW PRESSURE ACROSS EASTERN MONTANA INTO WESTERN SOUTH DAKOTA. SOUTHWESTERLY WINDS HAVE KEPT TEMPERATURES RATHER MILD OVERNIGHT. WATER VAPOR IMAGERY SHOWS FAST MOVING SHORTWAVE IN WYOMING. CURRENT SPEED HAS THIS MOVING INTO WESTERN SOUTH DAKOTA THIS MORNING. OVERALL 00Z GFS/NAM IN DECENT AGREEMENT THROUGH THE PERIOD. 06Z RUC/NAM SEEM TO HAVE A BETTER HANDLE ON CURRENT WAVE MOVING THROUGH WYOMING...BRINGING BEST LIFT ACROSS NORTHWEST SOUTH DAKOTA TODAY. TONIGHT...BETTER FOCUS SHIFTS SOUTHWARD AS UPPER LEVEL TROF DIGS ACROSS THE WESTERN U.S. FOR THURSDAY/FRIDAY AREA WILL BE UNDER WEAK TROF IN NORTHERN JET STEAM...WHILE STRONG WAVE MOVES ACROSS THE CENTRAL/SOUTHERN ROCKIES. HAVE TRIMMED BACK POPS ACROSS THE AREA...AS THIS IS TYPICALLY A DRY PATTERN FOR THE FORECAST AREA. EXTENDED...DRY AND RELATIVELY MILD WX PATTERN TO CONTINUE INTO EARLY NEXT WEEK. SOME WEAK SHORTWAVE ENERGY WILL CROSS THE NORTHERN PLAINS IN NEAR ZONAL FLOW...BUT WITH SIGNIFICANT LOW LEVEL MOISTURE LACKING...ANY CHANCES LOOK MINIMAL ENOUGH TO KEEP FORECAST DRY. && .AVIATION...VFR CONDITIONS CAN BE EXPECTED OVER MOST OF THE AREA WITH SOME LIGHT SNOW EXPECTED OVER NORTHEASTERN PORTIONS OF WYOMING AND NORTHWESTERN PORTIONS OF SOUTH DAKOTA BY LATE AFTERNOON. THERE MAY BE SOME MVFR CEILINGS AND SNOW ACROSS THE NORTHERN PORTIONS OF TWEB ROUTE 260 TO BISMARK AFTER 18Z. && .UNR...WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 815 PM MST WED JAN 18 2006 .SYNOPSIS...A COLD UPPER LEVEL TROUGH WILL SETTLE OVER THE GREAT BASIN THROUGH THURSDAY. HIGH PRESSURE ALOFT WILL FOLLOW FOR FRIDAY...THEN A WEAK WEATHER DISTURBANCE WILL IMPACT THE AREA FRIDAY NIGHT THROUGH SATURDAY. && .DISCUSSION...SIGNIFICANT SNOW STORM TAKING SHAPE. BAROCLINIC ZONE THAT BROUGHT 4-5 INCH SNOWFALL RATES TO THE MOUNTAINS AND A PERIOD OF HEAVY SNOW TO THE NORTHERN VALLEYS IS OVER CENTRAL UTAH AND HAS BEEN PRODUCING MODERATE TO HEAVY SNOW FROM DELTA TO PRICE. UPDATED EARLIER TO ACCOUNT FOR SNOWFALL IN PRICE. TO THE NORTH RADAR RETURNS ARE BEGINNING TO INCREASE ACROSS THE DESERTS AND SOUTHERN WASATCH FRONT. APPEARS THAT THE SNOW EVENT IN THE NORTH IS NOT GOING TO BE A TRADITIONAL TERRAIN ENHANCEMENT SCENARIO. 00Z NAM AND RUC ARE INLINE WITH THE 18Z GFS AND NAM RUNS. SIGNIFICANT COOLING ALOFT TONIGHT WILL FURTHER STEEPEN LAPSE RATES AND CREATE DRY ADIABATIC LAPSE RATES OVERNIGHT. IN THIS INSTABILITY AND MOIST LAYER MODELS DEVELOP A 12-15 HOUR PERIOD OF DEEP OMEGA OVER CENTRAL AND NORTHERN UTAH TONIGHT INTO THURSDAY AM. THE HEAVIEST SNOW APPEARS TO BE TARGETED FOR AREAS BETWEEN OGDEN TO THE SANPETE VALLEY. A WELL DEFINED 700 MB WAVE ON ALL MODELS DROPS INTO NORTHERN UTAH NEAR 06Z BUT MAKES LITTLE PROGRESS AS IT TENDS TO DEEPEN AND WAIT FOR THE 500 MB TROUGH THAT IS NOW HANGING BACK OVER NORTHWEST NEVADA. 700 MB WINDS OVER THE GSL DO VEER TO THE NORTHWEST AFTER MIDNIGHT AS THE DEEPENING OCCURS. THERE IS ALSO A SURFACE REFLECTION THAT IS NOW JUST ACROSS THE BORDER IN NEVADA AND WILL MOVE ACROSS THE DESERTS AND REACH THE GSL NEAR MIDNIGHT. THIS BROAD UPPER TROUGH COULD KEEP SNOWFALL GOING INTO THE MORNING HOURS FOR CENTRAL AND NORTHERN UTAH. COLD AND DEEP AIR MASS SHOULD ALLOW FOR GREAT DENTRITIC SNOW GROWTH TONIGHT AND THURSDAY MORNING. THE BAROCLINIC ZONE GETS PUSHED SLOWLY SOUTHWARD OVERNIGHT WHILE JET ENERGY NEARLY PARALLEL ROUNDS THE BASE OF THE MEAN UPPER TROUGH OVER THE GREAT BASIN AND EXITS ACROSS SOUTHEAST UTAH LATE TONIGHT. THIS PROVIDES LARGE SCALE DIVERGENCE OVER MOST OF UTAH. THUS SNOW SHOULD ALSO OCCUR IN SOUTHWEST UTAH AND SOUTH CENTRAL UTAH OVERNIGHT. 00Z NAM IS NOW GENERATING SOME PRECIPITATION IN THESE AREAS AND RADAR ALREADY DEPICTS DEVELOPING PRECIPITATION IN SOUTHWEST UTAH. AS THE JET STREAK ON WATER VAPOR IN SOUTH CENTRAL NEVADA CUTS ACROSS SOUTHERN UTAH TONIGHT IT MAY GIVE THE BAROCLINIC ZONE A PUSH SOUTHWARD....WHICH SPLITS SOUTH CENTRAL UTAH FROM THE STRONGER FORCING IN THE NORTH AND THE BAROCLINIC ZONE. THIS AREA IS HAVING THE HEAVY SNOW NOW WITH 2 INCHES REPORTED IN DELTA AND OBSERVATIONS DEPICTING STEADY SNOW EXTENDING TO RICHFIELD AND PRICE. WILL KEEP WARNINGS AND ADVISORIES IN PLACE...BUT WILL NEED TO MAKE CHANGES. I-15 CORRIDOR OF SOUTHWEST UTAH COULD GET A COUPLE INCHES OF SNOW AS DYNAMICS PASS BY OVERNIGHT BUT BEST OROGRAPHIC LIFT OCCURS ON THURSDAY IN THE NORTHWEST FLOW. MAY NEED TO EXPAND ADVISORY INTO CASTLE COUNTRY AS BAROCLINIC ZONE IS SLOW TO DEPART SOUTH THIS EVENING AND NORTHWEST DOWNSLOPING FLOW DOES NOT DEVELOP UNTIL LATE TONIGHT. ALSO THE DESERTS OF NORTHWEST UTAH COULD GET SIGNIFICANT SNOWFALL OVERNIGHT...LIKE DUGWAY AREA SO WILL ADD AT LEAST ADVISORY THERE...AND CONSIDER UPGRADE FOR SANPETE VALLEY AND WEST CENTRAL UTAH ZONE 15 AS MUCH OF THESE AREAS WILL BE IN THE SWATH OF GOOD SYNOPTIC LIFT OVERNIGHT. THE UPPER TROUGH THAT MOVES OVER UTAH TONIGHT DIGS INTO CENTRAL UTAH AND SHIFT WINDS AT 500 MB TO NORTHWEST IN NORTHERN UTAH EARLY THURSDAY MORNING. THIS TROUGH APPEARS TO CATCH UP WITH THE SLOWLY SOUTHWARD MOVING BAROCLINIC ZONE AND SHOULD ENHANCE PRECIPITATION NEAR THE ARIZONA BORDER TOMORROW MORNING. ADDITIONAL ENERGY AND COLDEST POCKET OF AIR IS NOW OVER NORTHERN CALIFORNIA AND THIS HEADS EAST TO SOUTHEAST INTO ALL OF WESTERN UTAH LATE TONIGHT. COLDEST ALOFT SPILLS OVER UTAH ON THURSDAY WITH -31 AT 500 MB SO GOOD INSTABILITY WILL KEEP SNOW SHOWERS EVEN AFTER GOOD SYNOPTIC LIFT DIMINISHES THURSDAY MORNING. SNOW SHOWERS FOR THE I-15 CORRIDOR VALLEYS AND THE MOUNTAINS WITH NORTHWEST FACING SLOPES GETTING THE GREATEST ACCUMULATIONS. SNOW RAPIDLY DECREASING THURSDAY NIGHT BUT WILL LINGER LONGEST ON THE I-15 CORRIDOR. NOT MUCH OF A SHORT WAVE RIDGE ON FRIDAY BUT FLOW ALOFT DOES BACK TO WESTERLY AND WARM AIR ADVECTION DEVELOPS. COULD DEVELOP SOME LIGHT SNOW IN THE BEAR RIVER RANGE. A FAST MOVING SHORT WAVE TROUGH IS ON TRACK TO DIG ACROSS NORTHERN UTAH LATER FRIDAY NIGHT AND SATURDAY MORNING. THIS WOULD BE A RATHER QUICK SHOT OF SNOW TO THE NORTHERN VALLEYS AND MOUNTAINS. THEN SURFACE HIGH WILL QUICKLY BUILD IN FROM IDAHO AND INSTABILITY SNOW SHOWERS WILL DIMINISH. SOME SNOWFALL COULD REACH INTO THE CENTRAL UTAH AS THE MEAN UPPER TROUGH DIGS OVER THE STATE. && .AVIATION...SEE SLCTAFSLC. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...WINTER STORM WARNING UTZ007>009 UNTIL 6 PM THURSDAY. ...HEAVY SNOW WARNING UTZ001>004 UNTIL 6 PM THURSDAY. ...HEAVY SNOW WARNING UTZ014 TONIGHT THRU THURSDAY MORNING ...SNOW ADVISORY UTZ006-010-015-017 UNTIL 6 PM THURSDAY. ...SNOW ADVISORY UTZ005 TONIGHT WY...SNOW ADVISORY UNTIL 6 PM THURSDAY FOR WYZ021. && $$ PUBLIC...TARDY AVIATION...SMITH ut AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 245 AM MST THU JAN 19 2006 SOUTHWEST AND SOUTH-CENTRAL ARIZONA...AND SOUTHEAST CALIFORNIA FORECAST DISCUSSION .SYNOPSIS... THE FIRST IN A SERIES OF PACIFIC WEATHER DISTURBANCES WILL MOVE THROUGH ARIZONA TODAY AND TONIGHT. BREEZY AND COOL WEATHER CAN BE EXPECTED OUT OF THIS SYSTEM...AS RATHER LOW HUMIDITY LEVELS PERSIST FROM SOUTHEAST CALIFORNIA INTO SOUTH-CENTRAL ARIZONA. A WEAK HIGH PRESSURE SYSTEM WILL RESULT IN MOSTLY SUNNY SKIES ON FRIDAY. ANOTHER LOW PRESSURE SYSTEM WILL BRUSH BY OUR AREA ON SATURDAY...BUT ONCE AGAIN NO SHOWERS ARE EXPECTED. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL THROUGH EARLY NEXT WEEK. && .SHORT TERM... TODAY THROUGH SATURDAY... THICK BAND OF HIGH LEVEL CLOUDS MOVING THROUGH AZ AT THIS TIME AHEAD OF A DEEPENING TROUGH. 07Z RUC PUT ONE VORT LOBE OVER RIVERSIDE COUNTY WHILE THE DOMINANT SYSTEM WAS JUST NORTHWEST OF LAS VEGAS. PIREP BEFORE MIDNIGHT INDICATED TOPS NEAR 27K FT...AND KIWA VAD WIND PROFILE SHOWED CLOUDS ABOUT 10 THSD FT THICK. LAST EVENINGS SOUNDINGS WERE AGAIN VERY DRY...WITH MODERATE TO STRONG WESTERLY FLOW ALOFT. 700MB FLOW INCREASES TO 35-40KTS OVER SW AZ BY 12Z AND WILL SHOW BREEZY TO WINDY FOR LOWER COLORADO RIVER VALLEY AND SOUTHEAST CALIFORNIA TODAY. PREDAWN WINDS AT IMPERIAL EVEN BECAME GUSTY FOR AWHILE. STILL NOT MUCH MOISTURE WITH THIS SYSTEM...BUT MODEL SOUNDINGS SHOW A THICKENING AND LOWERING OF CLOUDS AHEAD OF THE COLD FRONT. HIGHER ELEVATIONS EAST OF GLOBE MAY SEE SOME VIRGA...AND THATS ABOUT IT. UPPER RIDGE WILL NOT BE SIGNIFICANT AT ALL FRIDAY. NEW GFS CALLS FOR A SPLIT FLOW TO FORM OVER SRN CALIFORNIA. BY 12Z SATURDAY THE LATEST GFS HAS ABOUT THE SAME TIMING OF THE TROUGH...COMPARED TO THE PREVIOUS RUN...BUT HEIGHTS NOT QUITE AS LOW. WE STILL EXPECT THE COLDEST MORNING TO BE SATURDAY MORNING AT MOST SITES. LOW TEMPERATURES LIKELY TO DIP INTO UPPER 20S IN THE COLDEST SPOTS AROUND THE METRO PHOENIX AREA. && .LONG TERM... SATURDAY NIGHT THROUGH WEDNESDAY... NOT MUCH CHANGE IN THE EXTENDED PERIOD AS MEDIUM RANGE MODEL SOLUTIONS AGREE THAT THE WESTERN US WILL CONTINUE TO BE DOMINATED BY A BROAD UPPER LEVEL TROUGH. MORE UNCERTAINTY RESIDES IN SEVERAL STRONGER SHORTWAVES STILL FORECAST TO MOVE THROUGH THE MEAN FLOW...AND THESE FEATURES WILL EVENTUALLY DICTATE TEMP TRENDS...AS WELL AS PRECIP CHANCES THROUGH EARLY NEXT WEEK. EXPECTING A MAINLY ZONAL UPPER FLOW PATTERN ON FRIDAY AND SATURDAY WITH VARIABLE AMOUNTS OF HIGH CLOUDS. TEMPS EXPECTED TO REMAIN A FEW DEGREES BELOW NORMAL DUE TO WEAK CAA ON FRIDAY...AND COOL BOUNDARY LAYER TEMPS. MORE SIGNIFICANT LOW PRESSURE SYSTEM WILL DEVELOP OVER THE PAC NW ON SATURDAY AND THEN BEGIN TO DROP SOUTHWARD TOWARD THE REGION ON SUNDAY. LATEST 12Z OPERATIONAL RUNS FROM THE GFS/ECMWF/UKMET/CANADIAN (AS WELL AS VARIOUS ENSEMBLE MEMBERS) SHOWING QUITE A BIT OF VARIABILITY WITH THE TRACK OF THE LOW...GENERALLY PRODUCING A CLOSED LOW ANYWHERE FROM KLAX TO KFLG BY 12Z MONDAY. DUE TO UNCERTAINTY IN THE STRENGTH/TIMING/MOISTURE AVAILABILITY OF THE SYSTEM...DECIDED TO PLAY THE PERSISTENCE GAME AND KEPT THE FORECAST DRY THROUGH TUESDAY. THIS SYSTEM BARES WATCHING HOWEVER...ESPECIALLY IF THE MODEL SOLUTIONS BEGIN TRACK THE LOW FURTHER WEST AND/OR SOUTH...AND THUS SHOW A BIT MORE MOISTURE BEING ENTRAINED INTO THE SYSTEM...STAY TUNED. && .AVIATION...12Z TAFS...TAFS ADEQUATELY DEPICT EXPECTED WEATHER. SEE TAFS PHXTAFPHX...PHXTAFIWA...PHXTAFYUM...LAXTAFBLH AND LAXTAFIPL FOR MORE DETAILED INFORMATION. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX SIPPLE/ELLIS az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 455 AM EST THU JAN 19 2006 .DISCUSSION... MAIN FCST CONCERNS ARE SNOW CHANCES/AMOUNTS TODAY INTO THIS EVENING. WV IMAGERY...00Z RAOBS AND RUC ANALYSIS INDICATED A LOW AMPLITUDE PATTERN WITH A BROAD TROF OVER THE WRN CONUS AND CONFLUENT MID/UPR LVL FLOW OVER THE GRT LAKES BTWN A FLAT RDG OVER THE CNTRL CONUS AND A TROF OVER ERN CANADA. MAIN UPSTREAM SHRTWV WAS MOVING NE THROUGH CNTRL SD WITH ANOTHER OVER NW IA. AT THE SFC...A RDG EXTENDED FROM WRN ONTARIO. UPSTREAM...A BROAD 1001 MB LOW WAS LOCATED OVER CNTRL NEB/KS WITH A WARM FRONT THROUGH NRN IA TO NEAR THE WI/IL BORDER. RADARS AND SFC OBS INDICATED MAIN BATCH OF PCPN AS SNOW OVER CNTRL INTO NW SD WHILE SOME LIGHT RAIN HAD DEVELOPED OVER NW IA. TODAY INTO THIS EVENING...EVEN THOUGH MOISTURE INFLOW INTO THE SYSTEM MOVING OUT OF THE PLAINS IS NOT IMPRESSIVE...VIGOROUS MID/UPR LVL DYNAMICS SHOULD BRING AN AREA OF LIGHT TO MODERATE SNOW INTO UPPER MI. MDLS SUGGEST THAT UPWARD MOTION WILL BE ENHANCED BY FAIRLY STRONG UPR LVL DIV WITH COUPLED UPR LVL JET STRUCTURE AND ASSOCIATED AREAS OF 700-500 FRONTOGENESIS FROM 18Z-24Z. DECENT SNOWFLAKE GROWTH IS ALSO EXPECTED...PER NAM/GFS OMEGA IN -12C TO -17C LYR. HOWEVER...SIGNIFICANT DIFFERENCES REMAIN IN HOW MDLS PLACE MAX UPWARD MOTION AND ASSOCIATED QPF. THE NAM CONFINES A GREATER PORTION OF THE PCPN AREA IN NRN WI INTO FAR S UPR MI WHERE GREATEST ISOBAR PACKING IS EVIDENT IN THE 290K-295K LYR IN RESPONSE TO CONFLUENT FLOW TO THE NORTH. THE GFS ON THE OTHER HAND...KEEPS GREATER FOCUS ON THE SD SHRTWV AND SHOWS GREATER SATURATION/ LOW COND PRES DEF FARTHER NORTH WITH TYPICALLY BROADER AREA THROUGH UPR MI. GIVEN UPSTREAM PCPN TRENDS...CANNOT RULE OUT EITHER SCENARIO WITH POSSIBILITY OF MORE THAN ONE SIGNIFICANT PCPN BAND DEVELOPING. IN LINE WITH THE CONSENSUS...WENT WITH CATEGORICAL POPS TAPERING TO CHANCE VALUES OVER THE KEWEENAW. USED QPF FROM VALUES AT OR SLIGHTLY BLO NAM/GFS BLEND AND SNOW WATER RATIO AROUND 16/1...ESTIMATED FROM ROEBBER EXPERIMENTAL ALGORITHM. THIS WOULD GIVE 2-3 INCH AMOUNTS OVER FROM THE S INTO CWA. GIVEN VIGOROUS DYNAMICS AND POSSIBILITY OF EVEN HIGHER SNOW/WATER RATIOS...WOULD NOT BE SURPRISED TO SEE A NARROW STRIPE OF 4-5 INCH AMOUNTS. HOWEVER....CONFIDENCE IN LOCATION OF SUCH HEAVIER AMOUNTS IS LOW AND HAVE OPTED NOT TO ISSUE HEADLINES YET. FRI INTO FRI NIGHT...WEAK CAA IN THE WAKE OF THE LOW PUSHES 850 MB TEMPS TO NEAR -10C...WHICH WILL BE MARGINAL FOR LES. SO... ONLY CHANCE SHSN WERE INCLUDED FOR LOCATIONS FAVORED BY WNW FLOW...PER GFS/UKMET. THE NAM KEEPS THE COLDER AIR...MAINLY NORTH OF LAKE SUPERIOR. WINDS FCST TO VEER MORE NW AS RDG BUILDS TOWARD THE AREA AND STRENGTHENING LOW PRES MOVES TOWARD THE ERN LAKES. SAT INTO SAT NIGHT...THE UKMET AND LAST COUPLE GFS RUNS SUGGEST ANOTHER SHRTWV AND ASSOCIATED FGEN WILL MOVE FROM THE NRN PLAINS INTO THE WRN LAKES SUPPORTING CHANCE FOR ANOTHER BAND OF SNOW INTO UPR MI. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE UPTON NY 300 AM EST THU JAN 19 2006 .NEAR TERM (TODAY)... WSW WINDS CONTINUE TO DIMINISH. SCATTERED STRATO/ALTO CUMULUS WAVE CLOUDS DUCTING ALONG AT THE BASE OF THE SUBSIDENCE INVERSION NORTH OF THE REGION. RUC SOUNDINGS SEEM TO DEPICT THIS NICELY. START TODAY SUNNY. MINOR SHORT WAVE LOCATED NEAR KANSAS CITY AS OF 06Z TRACKS ACROSS THE REGION IN THE MID TO LATE AFTERNOON (19Z TO 23Z) WITH BKN HIGH DECK. GFS HAS THIS FEATURE NICELY INITIALIZED AND HAVE FOLLOWED IT'S EXTRAPOLATION OF RH FIELD AT 500-300HPA. TEMPS...MOS TEMPS ARE CLOSE TO ONE ANOTHER AND HAVE NO REAL REASON TO DEVIATE. && .SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)...SW FLOW ALOFT WILL KEEP THINGS MILD AND DRY THROUGH FRIDAY NIGHT. WILL AGAIN GO WITH MOS (A BLEND OF MAV AND FWC) TEMPS. ONSHORE (JANUARY SEA BREEZE?) KEEPS TEMPS DOWN A TAD ALONG THE COAST (LONG ISLAND) ON FRIDAY. GFS DOES SHOW SOME WEAK COLD ADVECTION AT 850 ON FRIDAY WITH 850 HPA TEMPS DROPPING ABOUT 2 DEGREES C TO +3 BY 00Z. OVERALL JANUARY THAW CONTINUES ON FRIDAY. PARTLY CLOUDY SKY WITH JET CIRRUS MAINLY NORTH. FOR SATURDAY...21Z SREF...00Z NAM AND GFS ALL FAIRLY CONSISTENT IN FORECASTING A LIGHT PRECIPITATION EVENT WITH A COLD FROPA AROUND 18Z. POPS IN THE HIGH CHANCE LEVEL...BUT MAY BE TOO HIGH. ONLY A FEW HUNDREDTHS OF QPF EXPECTED. REMOVED PCPN FROM SATURDAY NIGHT BASED ON FRONT CLEARING REGION. && .LONG TERM (SUNDAY THROUGH WEDNESDAY)...SOMEWHAT OF A COOL DOWN...BUT STILL SLIGHTLY ABOVE NORMAL. LOW CONFIDENCE IN GFS...BUT HAVE ADDED CHANCE FOR MIXED PCPN LATE MONDAY INTO TUESDAY AS SYSTEM PASSES SOUTH OF THE REGION. THIS IN COLLABORATION WITH SURROUND COASTAL OFFICES. && .HYDROLOGY...ALL WATCHES WERE DISCONTINUED IN CT AS BOSFLWBOX WARNING NOW IN EFFECT. NO SIG PCPN EXPECT THROUGH WEEKEND. && .AVIATION... VFR CONDS EXPECTED OVER THE NEXT 24 HOURS. WINDS AND GUSTS WILL PICK UP FROM W 15-20KT WITH GUSTS 20-25KT AFTER DAYBREAK WITH DAYTIME MIXING...BUT THEN DIMINISH AFTER 16Z AS PRESSURE GRADIENT CONTINUES TO WEAKEN. SOME HIGH AND MID DECK LATE THIS AFTERNOON/EVENING AS SURFACE RIDGING BUILDS INTO THE AREA. && .MARINE... WESTERLY PRESSURE GRADIENT AND CAA WILL WANE THROUGH THE MORNING AS LOW PRESSURE TRACKS INTO THE CANADIAN MARITIMES AND SOUTHERN HIGH BUILDS INTO WESTERN ATLANTIC. WILL TRIM GALES TO ONLY CENTRAL AND EASTERN OCEAN WATERS AND EASTERN SOUND THIS MORNING WITH GUSTS UP TO 40 KT...WHICH SHOULD FALL TO SCA BY LATE MORNING. SCA WINDS FOR REMAINDER OF WATERS. WINDS FALL BELOW SCA OVER ALL WATERS TONIGHT...BUT WILL CONTINUE SCA ON OCEAN WATERS AS SEAS SHOULD REMAIN AROUND 5 FT WITH PROLONGED SW FETCH AROUND WESTERN ATLANTIC HIGH. SW WINDS SHOULD INCREASE TO SCA ON THE OCEAN ONCE AGAIN ON SATURDAY AHEAD OF NEXT FRONTAL SYSTEM...AND THEN SCA POSSIBLE ON ALL WATERS LATE SAT/SAT NIGHT WITH CAA AND TIGHT NW GRADIENT BEHIND DEPARTING LOW. MORE TRANQUIL CONDITIONS SUNDAY NIGHT INTO EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE WATERS. LOW WATER PROBLEMS POSSIBLE THIS MORNING ACROSS WESTERN SOUND WITH TIDAL DEPARTURES OF 3 TO 3.5 FT...DUE TO STRONG WESTERLY FLOW. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NJ...NONE. NY...NONE. MARINE...GALE WARNING FOR ANZ330-350-353 UNTIL 11 AM THURSDAY. ...SMALL CRAFT ADVISORY FOR ANZ330 FROM 11 AM THURSDAY TO 4 PM THURSDAY. ...SMALL CRAFT ADVISORY FOR ANZ350-353 FROM 11 AM THURSDAY TO 1 PM SUNDAY. ...LOW WATER ADVISORY FOR ANZ335 UNTIL 11 AM THURSDAY. ...SMALL CRAFT ADVISORY FOR ANZ335-338 UNTIL 11 AM THURSDAY. ...SMALL CRAFT ADVISORY FOR ANZ355 UNTIL 1 PM SUNDAY.&& $$ TONGUE AVIATION/MARINE...VAZ ny AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE UPTON NY 1055 AM EST THU JAN 19 2006 .NEAR TERM (REST OF TODAY)... MADE MINOR CHANGES IN GRIDS TO CLOUD COVER/WINDS AND HOURLY TEMPS/DEWPOINTS FOR TODAY...BUT CORE OF FORECAST IS ON TRACK...SO MAIN REASON FOR ISSUING UPDATED ZONES IS TO REMOVE MORNING WORDING. NICE TO HAVE A QUIET DAY TODAY WITH HIGH PRES RIDGING IN SFC AND ALOFT. WILL HAVE INCRS IN HIGH CLDS THIS AFTN IN RESPONSE TO WARM FRONT APPROACHING AT 925-850HPA (REALLY JUST A WIND SHIFT LINE AT THE SURFACE WITH NO REAL THERMAL DISTINCTION). && .MARINE... WITH GUSTS BELOW 34KT FOR PAST COUPLE OF HOURS AND DIMINISHING TREND NOTED IN SUSTAINED WINDS AS WELL (IN ADDITION TO LOWER WIND SPEEDS MOVING IN ALOFT) AM LOWERING GALE TO SCA THIS PACKAGE. SEAS THOUGH OVER SOUND AND COASTAL WATERS REMAIN SOLIDLY IN SCA CRITERIA AS WELL. THANKS TO BOX FOR COORD. && .AVIATION... VFR FOR NEXT 24 HOURS...HAVE REMOVED GUSTINESS FROM TAFS AS MOST LOCATIONS NO LONGER ARE REPORTING GUSTS MORE THAN 10 KT ABOVE SUSTANED VALUES. WINDS ALOFT ARE DIMINISHING JUST ENOUGH TO KEEP TAF SIGHTS JUST BELOW THRESHOLD FOR LLWS...STILL COULD BE A BIT BUMPY WHILE TAKING OFF/LANDING THROUGH MID AFTN THOUGH. && PREVIOUS DISCUSSION... (ISSUED 300 AM EST THU JAN 19 2006) NEAR TERM (TODAY)... WSW WINDS CONTINUE TO DIMINISH. SCATTERED STRATO/ALTO CUMULUS WAVE CLOUDS DUCTING ALONG AT THE BASE OF THE SUBSIDENCE INVERSION NORTH OF THE REGION. RUC SOUNDINGS SEEM TO DEPICT THIS NICELY. START TODAY SUNNY. MINOR SHORT WAVE LOCATED NEAR KANSAS CITY AS OF 06Z TRACKS ACROSS THE REGION IN THE MID TO LATE AFTERNOON (19Z TO 23Z) WITH BKN HIGH DECK. GFS HAS THIS FEATURE NICELY INITIALIZED AND HAVE FOLLOWED IT'S EXTRAPOLATION OF RH FIELD AT 500-300HPA. TEMPS...MOS TEMPS ARE CLOSE TO ONE ANOTHER AND HAVE NO REAL REASON TO DEVIATE. SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... SW FLOW ALOFT WILL KEEP THINGS MILD AND DRY THROUGH FRIDAY NIGHT. WILL AGAIN GO WITH MOS (A BLEND OF MAV AND FWC) TEMPS. ONSHORE (JANUARY SEA BREEZE?) KEEPS TEMPS DOWN A TAD ALONG THE COAST (LONG ISLAND) ON FRIDAY. GFS DOES SHOW SOME WEAK COLD ADVECTION AT 850 ON FRIDAY WITH 850 HPA TEMPS DROPPING ABOUT 2 DEGREES C TO +3 BY 00Z. OVERALL JANUARY THAW CONTINUES ON FRIDAY. PARTLY CLOUDY SKY WITH JET CIRRUS MAINLY NORTH. FOR SATURDAY...21Z SREF...00Z NAM AND GFS ALL FAIRLY CONSISTENT IN FORECASTING A LIGHT PRECIPITATION EVENT WITH A COLD FROPA AROUND 18Z. POPS IN THE HIGH CHANCE LEVEL...BUT MAY BE TOO HIGH. ONLY A FEW HUNDREDTHS OF QPF EXPECTED. REMOVED PCPN FROM SATURDAY NIGHT BASED ON FRONT CLEARING REGION. LONG TERM (SUNDAY THROUGH WEDNESDAY)... SOMEWHAT OF A COOL DOWN...BUT STILL SLIGHTLY ABOVE NORMAL. LOW CONFIDENCE IN GFS...BUT HAVE ADDED CHANCE FOR MIXED PCPN LATE MONDAY INTO TUESDAY AS SYSTEM PASSES SOUTH OF THE REGION. THIS IN COLLABORATION WITH SURROUND COASTAL OFFICES. HYDROLOGY... ALL WATCHES WERE DISCONTINUED IN CT AS BOSFLWBOX WARNING NOW IN EFFECT. NO SIG PCPN EXPECT THROUGH WEEKEND. AVIATION... VFR CONDS EXPECTED OVER THE NEXT 24 HOURS. WINDS AND GUSTS WILL PICK UP FROM W 15-20KT WITH GUSTS 20-25KT AFTER DAYBREAK WITH DAYTIME MIXING...BUT THEN DIMINISH AFTER 16Z AS PRESSURE GRADIENT CONTINUES TO WEAKEN. SOME HIGH AND MID DECK LATE THIS AFTERNOON/EVENING AS SURFACE RIDGING BUILDS INTO THE AREA. MARINE... WESTERLY PRESSURE GRADIENT AND CAA WILL WANE THROUGH THE MORNING AS LOW PRESSURE TRACKS INTO THE CANADIAN MARITIMES AND SOUTHERN HIGH BUILDS INTO WESTERN ATLANTIC. WILL TRIM GALES TO ONLY CENTRAL AND EASTERN OCEAN WATERS AND EASTERN SOUND THIS MORNING WITH GUSTS UP TO 40 KT...WHICH SHOULD FALL TO SCA BY LATE MORNING. SCA WINDS FOR REMAINDER OF WATERS. WINDS FALL BELOW SCA OVER ALL WATERS TONIGHT...BUT WILL CONTINUE SCA ON OCEAN WATERS AS SEAS SHOULD REMAIN AROUND 5 FT WITH PROLONGED SW FETCH AROUND WESTERN ATLANTIC HIGH. SW WINDS SHOULD INCREASE TO SCA ON THE OCEAN ONCE AGAIN ON SATURDAY AHEAD OF NEXT FRONTAL SYSTEM...AND THEN SCA POSSIBLE ON ALL WATERS LATE SAT/SAT NIGHT WITH CAA AND TIGHT NW GRADIENT BEHIND DEPARTING LOW. MORE TRANQUIL CONDITIONS SUNDAY NIGHT INTO EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE WATERS. LOW WATER PROBLEMS POSSIBLE THIS MORNING ACROSS WESTERN SOUND WITH TIDAL DEPARTURES OF 3 TO 3.5 FT...DUE TO STRONG WESTERLY FLOW. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NJ...NONE. NY...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ350-353-355 UNTIL 1 PM SUNDAY. ...SMALL CRAFT ADVISORY FOR ANZ330-335 UNTIL 4 PM THURSDAY. && $$ NEAR TERM/MARINE/AVIATION...MALOIT ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 935 AM EST THU JAN 19 2006 .TODAY...PATCH OF CLOUDINESS OVER WESTERN NORTH CAROLINA WILL QUICKLY PASS THROUGH THE FORECAST AREA EARLY THIS AFTERNOON. GFS SHOWS MOISTURE THINNING OUT AS IT MOVES EAST SO ZONE FORECAST OF MOSTLY SUNNY STILL LOOKS GOOD. NO CHANGES NEEDED THIS MORNING. && .AVIATION...LATEST RUC CROSS SECTIONS SHOW MOISTURE ABOVE H5 ACROSS NRN SECTIONS OF THE TWEB ROUTE TO THE NORTH OF ECG AND HAVE INCLUDED SCT-BKN AC/CI IN THAT REGION. REST OF THE AREA SHOULD BE GENERALLY CLEAR THRU TONIGHT WITH VFR CONDITIONS PREVAILING. && .MARINE...SEAS HAVE DECREASED TO 5 FT OR LESS OVER ALL CSTL WATERS AND WILL LET SCA EXPIRE AT 15Z. AXIS OF SFC HIGH PRES RIDGE ALONG THE CAROLINA COAST WITH LIGHT GRADIENT ACROSS THE REGION. ANTICIPATE A COUPLE OF BENIGN DAYS TO FOLLOW. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FOR AMZ150-152-154-156- 158 UNTIL 10 AM THURSDAY. && $$ nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 918 AM EST THU JAN 19 2006 .SHORT TERM (REST OF TODAY)... SURFACE ANALYSIS SHOWS STRONG SOUTHERLY FLOW AHEAD OF A DEVELOPING LOW IN THE CENTRAL PLAINS. SATELLITE IMAGERY SHOWS BKN TO OVC AC DECK WORKING ACROSS REGION IN THE STRONG WARM AIR ADVECTION. MORNING SOUNDING SHOWS ~50KT AT 1000KFT AND LOTS OF DRY AIR IN THE LOWER PART OF THE ATMOSPHERE. HAVE UPDATED GRIDS AND ZONES TO LOWER TEMPS A DEGREE OR TWO. USING MORNING SOUNDING AND LOOKING AT LATEST NAM AND RUC IT LOOKS LIKE TEMPS ACROSS THE SOUTH WILL MAKE IT TO THE MID 50S WITH NORTHERN KENTUCKY SQUEAKING INTO THE UPPER 50S. WIND GUSTS LOOK GOOD FOR NOW BUT WILL MONITOR TO SEE IF THEY NEED TO BE BUMPED UP SINCE 50KTS IS NOT TO FAR OFF. TIPTON && .PREVIOUS DISCUSSION... (ISSUED 617 AM EST THU JAN 19 2006) AVIATION (12Z-12Z)... EXPECT TO SEE A CONTINUATION OF THE AC AND CIRRUS THROUGH THIS MORNING AS AREA OF MID LEVEL ISENTROPIC LIFT PUSHES ACROSS THE REGION. COULD SEE SOME CLEARING EARLY THIS AFTERNOON BEFORE BETTER ISENTROPIC LIFT DEVELOPS IN THE LOWER LEVELS LATE THIS AFTERNOON AND INTO TONIGHT. AS IT DOES...EXPECT SC DECK TO FORM ACROSS AREA AND SLOWLY LOWER INTO MVFR CONDITIONS OVERNIGHT. COULD EVEN SEE A FEW SPRINKLES OR LIGHT RAIN SHOWERS LATE IN THE TAF PERIOD BUT CHANCE APPEARS LOW ENOUGH TO LEAVE MENTION OUT OF TAFS ATTM. PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 410 AM EST THU JAN 19 2006 SHORT TERM (TODAY THROUGH SATURDAY)... CURRENT SURFACE ANALYSIS DEPICTS HIGH PRESSURE CENTERED OVER WEST VIRGINIA THIS MORNING WITH DEVELOPING LOW PRESSURE SYSTEM ACROSS THE CENTRAL PLAINS. WITH WAA KICKING IN...TEMPERATURES ARE SLOWLY RISING ACROSS THE REGION. REGION WILL EXPERIENCE ABOVE NORMAL TEMPERATURES TODAY (BY AS MUCH AS 20 DEGREES ABOVE NORMAL). WITH GOOD LOW LEVEL JET IN PLACE TODAY...COULD SEE SOME GUSTS TO 30 MPH. ISENTROPIC LIFT INCREASES OVERNIGHT INTO FRIDAY AHEAD LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS. GFS IS SLOWER THAN THE NAM WITH THE APPROACH OF THIS SYSTEM. HAVE SPEED UP CURRENT FORECAST POPS A BIT...BUT NOT AS QUICK AS THE NAM. HAVE HIGHEST POPS NEAR COLD FRONT WHICH LOOKS TO BE EAST OF CWA BY 12Z. HAVE ENDED ALL POPS BY SATURDAY AFTERNOON. FOR TEMPS...TODAY THRU FRIDAY...HAVE STUCK CLOSE TO MAV/MET NUMBERS...FWC NUMBERS SEEM TOO COLD. USED A BLEND REMAINDER OF FORECAST PERIOD. RLG LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... ONLY CHANCE TO EXTENDED WAS TO ADD PRECIP ON SUNDAY NIGHT AND MONDAY WITH APPROACH OF LOW PRESSURE SYSTEM FROM THE GULF REGION. PREVIOUS DISCUSSIONS FOLLOWS. (ISSUED 351 PM EST WED JAN 18 2006) EXTENDED MODELS ARE IN REASONABLE AGREEMENT IN THE EXTENDED WITH MORE VARIABILITY TOWARDS DAY 7. AT 500MB SOUTHWEST FLOW WILL DRIVE OUR WEATHER THROUGH THE EXTENDED. SATURDAY AN OPEN WAVE WILL RAPIDLY MOVE THROUGH THE OHIO VALLEY. ECMWF AND UKMET ARE A BIT FASTER THAN GFS BUT ALL SAME PATTERN. SUNDAY WILL BE DRY WITH HIGH PRESSURE. FOR MONDAY THE GFS IS BRINGING PRECIP BACK INTO FORECAST AREA AS IT DEVELOPS A LOW WHICH MOVES ACROSS THE TENNESSEE VALLEY. THE UKMET AND ECMWF DO NOT RESEMBLE THIS PATTERN. HOWEVER, DOING A DPROG/DT ON THE GFS IT HAS BEEN TRENDING TOWARD THIS SOLUTION FOR THE LAST 3 OR 4 RUNS. WILL NOT BUY OFF ON IT YET...HOWEVER WILL NOT IGNORE IT. THUS WILL GO WITH 25 POPS FOR MONDAY INTO MONDAY NIGHT. THE REST OF THE EXTENDED WILL BE DRY. TEMPERATURES THROUGH EXTENDED WILL REMAIN ABOVE NORMAL. TIPTON && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SHORT TERM... oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 950 AM EST THU JAN 19 2006 .DISCUSSION... HIGH PRESSURE CONTINUES AT THE SURFACE AND ALOFT TODAY...HIGH CLOUDS ARE SHIFTING TO THE EAST THIS MORNING. TEMPERATURES ARE A LITTLE SLOW IN WARMING BUT THE RUC AND OTHER SHORT TERM MODELS BUILD HEIGHTS WITH RIDGING ALOFT TODAY. ALSO A GOOD SOUTHWEST WIND DEVELOPS BY LATE MORNING OR EARLY AFTERNOON WHICH WILL WARM TEMPERATURES RAPIDLY EVEN WITH A FEW HIGH CLOUDS. WILL MAKE MINOR CHANGE TO WIND DIRECTION WITH NO OTHER CHANGES. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ TD tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1030 AM CST THU JAN 19 2006 .DISCUSSION... MORNING SURFACE ANALYSIS SHOWS LOW PRESSURE CENTERED OVER NORTHWEST MISSOURI...WITH WARM FRONT EXTENDING ACROSS FAR NORTHERN ILLINOIS. SOUTHERLY WINDS BRINGING MUCH WARMER AIR INTO THE KILX CWA...AS 16Z TEMPS HAVE RISEN INTO THE UPPER 40S AND LOWER 50S. THESE READINGS ARE A GOOD 15 TO 20 DEGREES WARMER THAN THEY WERE 24 HOURS AGO. SATELLITE IMAGERY SHOWS MOSTLY SUNNY SKIES ACROSS MUCH OF THE REGION...WITH HIGH CLOUDS STREAMING ACROSS THE PLAINS STATES INTO MISSOURI. STRONG RETURN FLOW OF LOW-LEVEL MOISTURE NOTED...WITH SURFACE DEWPOINTS CLIMBING INTO THE MIDDLE 40S ACROSS SOUTHERN ILLINOIS. LOW CLOUDS BEGINNING TO DEVELOP ALONG THIS MOISTURE PLUME FROM ARKANSAS NORTHEASTWARD INTO SOUTHERN ILLINOIS. BASED ON SATELLITE TRENDS AND NAM/RUC 925MB RH FIELDS...EXPECT CLOUDS TO CONTINUE TO DEVELOP NORTHEASTWARD DURING THE AFTERNOON. MOSTLY SUNNY SKIES WILL GRADUALLY GIVE WAY TO INCREASING CLOUDS...ESPECIALLY ACROSS THE E AND SE CWA. HAVE TWEAKED SKY GRIDS TO REFLECT THIS. HAVE ALSO BUMPED WINDS UP ALONG AND SOUTH OF I-72...AS AREA PROFILERS ARE SHOWING 50KT 925MB WINDS ACROSS SOUTHEAST MISSOURI INTO SOUTHERN ILLINOIS. WINDS ARE A BIT WEAKER FURTHER NORTH...WITH WINCHESTER PROFILER SHOWING 35 TO 40KT. HAVE ALSO RAISED HIGH TEMPS JUST A BIT...DUE TO STRONG WAA AND ABUNDANT SUNSHINE THIS MORNING. TEMPS WILL RANGE FROM THE MIDDLE 50S FAR NORTH...TO THE LOWER 60S SOUTHEAST. && .PREV DISCUSSION... MAIN CHALLENGE THIS FORECAST IS THE SYSTEM FOR FRIDAY THROUGH SATURDAY... WHERE THE RAIN SNOW LINE WILL SET UP AND HOW MUCH SNOW. THE MODELS STILL HAVE NOT SETTLED INTO ONE PRIMARY SOLUTION...WITH CHANGES FROM RUN TO RUN CONTINUING. MOST MODELS INDICATED A SLIGHT DECREASE IN THE STRENGTH OF THE LOW...KEEPING THE TROUGH POSITIVELY TILTED AND PROGRESSIVE. THE 00Z NAM TRENDED TOWARD THE 12Z AND 00Z GFS. THE GFS IS IN RELATIVE AGREEMENT WITH THE NAVY NOGAPS...THE MM5...AND THE UKMET. ALL THE MODELS CONTINUE TO INCREASE THE SPEED OF THE SYSTEM...WITH PRECIP MOVING IN FRIDAY AFTERNOON...AND MAKING SATURDAY DRY. HPC GAVE THE NOD TO THE GFS...AND WILL FOLLOW IT FOR THE DETAILS. SHORT TERM...TODAY THROUGH SATURDAY... AN INITIAL LOW PRESSURE SYSTEM IS EXPECTED TO MOVE BY TO OUR NW TODAY. A WARM FRONTAL BOUNDARY JUST TO THE NORTH OF OUR CWA WILL BE CLOSE TO THE PATH OF THE LOW. THE BULK OF THE MOISTURE WITH THIS LOW WILL BE NORTH OF THE TRACK. THE ONLY THING THAT SHOULD RESULT IS A FLOW OF MID AND HIGH CLOUDS FROM SW TO NE. THE PRIMARY LOW WILL EJECT FROM THE SC PLAINS ON FRIDAY MORNING... REACHING TO JUST SOUTH OF ST LOUIS BY 00Z SAT. ONCE AGAIN THE MAIN FORCING AND FOCUS FOR PRECIP WILL BE ALONG AND NORTH OF THE LOW... SO I INCREASED THE FRIDAY AFTERNOON POPS TO LIKELY IN THE NW HALF OF THE CWA. PRECIP TYPE WILL BE A CHALLENGE... WITH THE AIR COLUMN WARM ENOUGH FOR MOSTLY RAIN EVERYWHERE THROUGH 00Z. THE STRENGTH OF THE UVV MAY BE ENOUGH TO STRETCH AND COOL THE COLUMN TO BRING A RAPID CHANGE TO SNOW NORTHWEST OF THE ILLINOIS RIVER. ACCUMULATION UP TO AN INCH WILL BE POSSIBLE THERE THROUGH 00Z SAT...WITH THE BULK OF ADDITIONAL SNOW COMING BEFORE MIDNIGHT IN THE DEFORMATION ZONE. THERE APPEARS TO BE ENOUGH MOISTURE AND COOL AIR FOR 2 TO 4 INCHES ON SNOW ALONG AND NORTHWEST OF THE ILLINOIS RIVER. A SHARP CUTOFF TO THE RAIN SNOW LINE IS LIKELY...DUE TO THE WARM AIR IN PLACE AND WAA SOUTH OF THE WARM FRONT. SINCE 2 TO 4 INCHES IS IN THE ADVISORY CATEGORY... NO HEADLINES ARE NEEDED THIS FORECAST. WILL KEEP CLOSE WATCH ON THE THE TRACK AND STRENGTH OF THE LOW IN FUTURE RUNS FOR POSSIBLE HEADLINES. THE SYSTEM IS EXPECTED TO BE WELL EAST OF IL BY 12Z SATURDAY...AND I PULLED ALL MENTION OF PRECIP ON SATURDAY. HIGH PRESSURE SHOULD RAPIDLY BUILD IN BEHIND THE LOW... PROVIDING SOME BREAKS IN THE CLOUD COVER BY AFTERNOON. SATURDAY WILL BE A LITTLE COLDER THAN FRIDAY...BUT STILL ABOVE NORMAL. LONG TERM...SUNDAY THROUGH WEDNESDAY... ANOTHER SYSTEM IS ON TAP FOR SUNDAY NIGHT AND MONDAY. IT SHOULD PASS JUST SOUTH OF ILLINOIS... PROVIDING A CHANCE OF RAIN OR SNOW MAINLY FOR AREAS SOUTH OF I-70. OTHERWISE... PARTLY CLOUDY SKIES AND ABOVE NORMAL TEMPS SHOULD CONTINUE THROUGH MID NEXT WEEK. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BARNES/SHIMON il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 1111 AM CST THU JAN 19 2006 .DISCUSSION... EXTENSIVE CU FIELD STREAMING N ACROSS E TX AND N LA ATTM...WITH ONLY THE RUC MODEL INITIALIZING WELL OF THIS CLOUD FIELD AROUND 900MB. BASED ON 12Z KSHV/KLCH RAOBS...VERY STEEP CAP SHOULD REMAIN IN PLACE FOR A BETTER PART OF THE DAY...THUS TRAPPING CU IN OVER THE AREA AS STRONG WARM ADVECTION CONTINUES. WILL UPDATE THE ZONES TO GO MOSTLY CLOUDY MAINLY ALONG/S OF I-20 AND ALSO NW ZONES. ENOUGH MIXING ALONG I-30 MAY KEEP SKIES FROM GOING OVERCAST...ALLOWING TEMPS TO REACH FORECAST HIGHS. QUESTION HOW MUCH ADDITIONAL WARMING WE MAY SEE ELSEWHERE...ALTHOUGH DID LOWER MAX TEMPS A DEGREE OR SO IN THE UPDATE. WILL LET THE CURRENT LAKE WIND ADV. RUN THROUGH LATE AFTERNOON...AS WINDS ARE GUSTING IN EXCESS OF 25 KTS OVER MUCH OF THE ADV. AREA ATTM. THE EXCEPTION MAY BE OVER E/SE ZONES...BUT IF CLOUDS THIN BY AFTERNOON...MIXING WILL WORK THE STRONGER WINDS DOWNWARD TOWARDS THE SFC. OTHERWISE...CURRENT FORECAST IS IN GOOD SHAPE. && .PRELIMINARY POINT TEMPS/POPS... SHV 74 58 72 42 / 0 0 20 20 MLU 71 54 72 47 / 0 0 10 40 DEQ 72 50 72 40 / 0 0 20 10 TXK 73 58 72 42 / 0 0 20 20 ELD 72 54 72 42 / 0 0 20 20 TYR 75 59 74 40 / 0 0 20 20 GGG 75 58 72 40 / 0 0 20 20 LFK 74 57 77 45 / 0 0 10 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...LAKE WIND ADVISORY UNTIL 6 PM THURSDAY FOR THE FOLLOWING ZONES: COLUMBIA...HEMPSTEAD...HOWARD...LAFAYETTE...LITTLE RIVER...MILLER...NEVADA...SEVIER...AND UNION AR. LA...LAKE WIND ADVISORY UNTIL 6 PM THURSDAY FOR THE FOLLOWING ZONES: BIENVILLE...BOSSIER...CADDO...CALDWELL...CLAIBORNE...DE SOTO...GRANT...JACKSON...LA SALLE...LINCOLN...NATCHITOCHES...OUACHITA...RED RIVER...SABINE LA...UNION LA...WEBSTER...AND WINN. OK...LAKE WIND ADVISORY UNTIL 6 PM THURSDAY FOR THE FOLLOWING ZONES: AND MCCURTAIN. TX...LAKE WIND ADVISORY UNTIL 6 PM THURSDAY FOR THE FOLLOWING ZONES: ANGELINA...BOWIE...CAMP...CASS...CHEROKEE...FRANKLIN...GREGG...HARRISON...M RIVER...RUSK...SABINE TX...SAN AUGUSTINE...SHELBY...SMITH...TITUS...UPSHUR...AND WOOD. && $$ 15 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1142 AM EST THU JAN 19 2006 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE POTENTIAL FOR SNOW THIS AFTERNOON AND EVENING. WATER VAPOR IMAGERY AND RUC/NAM SHOWING A LONGWAVE TROUGH OVER THE CANADIAN MARITIME...NEARLY ZONAL FLOW ACROSS THE CONUS...AND ANOTHER LONGWAVE TROUGH DIGGING INTO THE SIERRA NEVADA. A WEAK SHORTWAVES EJECTED OUT AHEAD OF THIS LONGWAVE TROUGH ARE OVER MINNESOTA... EASTERN NEBRASKA...THE DAKOTAS...AND OVER COLORADO. THE SURFACE ANALYSIS INDICATE A LOW OVER NORTHEAST KANSAS AND OVER CENTRAL MANITOBA. A WARM FRONT EXTENDS AHEAD OF THE IOWA LOW ACROSS THE NORTHERN OHIO RIVER VALLEY. A COLD FRONT IS DRAPED ACROSS SOUTH CENTRAL CANADA FROM THE LOW OVER WINNIPEG. THE WEAK SHORTWAVE OVER WISCONSIN WILL SHIFT ACROSS THE SOUTHERN U.P. THIS AFTERNOON...WHILE THE SHORTWAVE OVER THE DAKOTAS MOVES INTO NORTHERN MINNESOTA AND WESTERN LAKE SUPERIOR. THE MANITOBA SURFACE LOW WILL MOVE NORTHEAST INTO NORTHEAST MANITOBA...WHILE THE KANSAS LOW MOVE INTO EASTERN IOWA. THIS LATTER ONE WILL DIRECT THE WARM FRONT INTO LOWER MICHIGAN. 290K ISENTROPIC ANALYSIS INDICATE SIGNIFICANT ASCENT OVER THE FORECAST AREA THIS AFTERNOON AHEAD OF THE APPROACHING WARM FRONT AND ACCOMPANYING LOW. THE MIXING RATIO WILL BE AROUND 3G/KG OVER THE SOUTHERN PART OF THE U.P. AND 2G/KG OVER THE NORTH THIS AFTERNOON AS PER NAM/RUC. THICKNESSES VALUES SEEM TO SUGGEST THAT OVERRUNNING OF THE FRONT WILL LIKELY PRODUCE A WET SNOW. LOOKING AT THE QPF VALUES FROM RUC/GEM/GFS/NAM SHOWING THE HEAVIEST CONCENTRATION WILL BE OVER THE SOUTHERN AND FAR WESTERN COUNTIES. THIS ALSO COINCIDES WELL WITH THE BEST UPPER LEVEL DYNAMICS. STILL KEEPING WITH THE 16/1 RATIO FOR THIS AFTERNOON... KEEP A VALUES UP TO 3 INCHES OVER THE SOUTHERN AND WESTERN U.P. THE NAM FORECAST SOUNDINGS FOR THIS AFTERNOON...SUGGEST THAT THERE IS EVEN SOME POTENTIAL OF LIGHT FREEZING RAIN OVER THE MNM AREA...HOWEVER...THE RUC DOES NOT SUPPORT THIS. WILL STILL ADD A CHANCE FOR -FZRA FOR SOUTHERN MENOMINEE COUNTY. THE CONDITIONS WILL CONTINUE INTO THE EVENING HOURS. MODELS MOVE THE SHORTWAVE OUT OF THE AREA THIS EVENING...AND BRINGS THE MINNESOTA SHORTWAVE OVER THE NORTHERN U.P. AT THE LOW LEVEL...WILL LOSE THE ISENTROPIC ASCENT AS THE SURFACE LOW MOVES INTO LOWER MICHIGAN. THE CANADIAN COLD FRONT WILL SLIDE INTO NORTHWEST ONTARIO. QPF VALUES SUGGEST SNOW WILL SHIFT A LITTLE NORTH BUT WILL GENERALLY WEAKEN BY LATE EVENING. CURRENT GRIDS LOOK GOOD. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1056 AM CST THU JAN 19 2006 .UPDATE... 12Z RUC USING THE 600 MB DEFORMATION VECTORS...AND THE 12Z NAM USING THE CONVEREGENCE OF THE FN VECTORS TO IDENTIFY LIFT AT 600 MB...BOTH SHIFT THE STRONG LIFT NORTH OF THE TWIN CITIES FOR THE REST OF TODAY. THE 12Z NAM 40KM N-S CROSS SECTION THROUGH CENTRAL MN IDENTIFY THE USUAL SUSPECTS FOR BANDED SNOW...NEGATIVE SATURATED EPV...FAVORABLE SNOW GROWTH TEMPERATURES...AND LIFT. HAVE SLICED OFF THE ADVISORY ACROSS THE TWIN CITIES TO DUNN COUNTY WI SOUTHWARD. ALL THE AVAILABLE MOISTURE IS BEING SQUEEZED OUT IN THE AREA RESPONDING TO FRONTOGENETICAL FORCING ACROSS NORTH PARTS OF CENTRAL MN AND WEST CENTRAL WI. && .PREV DISCUSSION... /ISSUED 345 AM CST THU JAN 19 2006/ DISCUSSION...TODAY THROUGH SATURDAY NIGHT INTERESTING FCST SHAPING UP OVER THE NEXT 12 TO 18 HRS...WITH SYSTEM CURRENTLY IN THE CNTRL PLAINS SET TO IMPACT THE AREA TODAY AND INTO THIS EVENING. ECHOES THAT DEVELOPED DURING THE LATE EVENING HRS ACRS THE NRN HALF OF THE CWA IN RESPONSE TO A VORT MAX THAT MOVED OUT OF THE DAKOTAS HAVE PRETTY MUCH DISSIPATED. VERY LITTLE PCPN ACTUALLY REACHED THE GROUND FROM THESE ECHOES...WITH VERY DRY AIR REMAINING ALOFT...AS EVIDENCED BY THE 19/00Z KMPX RAOB. INSPECTION OF THE LOCAL 88D MOSAIC AND SFC OBS IN SODAK SHOWS THAT THE MAIN SHOW HAS ALREADY BEGUN ACRS ERN SODAK...WITH A BAND OF ENHANCED REFLECTIVITY FROM APPROX PIERRE TO ABERDEEN. THIS PCPN HAS DEVELOPED IN RESPONSE TO A VORT MAX EVIDENT IN WV IMAGERY IN S CNTRL SODAK. SFC LO IS FCST TO MOVE TO THE ENE TODAY...TREKKING THRU SRN IA TO THE WI/IL BRDR BY 00Z TNGT. THIS MOVEMENT WILL PLACE PORTIONS OF CNTRL MN AND W CNTRL WI IN A FAVORABLE REGION OF MID LVL FRONTOGENESIS FROM MID MRNG AND INTO THE LATE AFTN HRS...RESULTING IN A BAND OF ENHANCED SNOW TOTALS...POSSIBLY APPROACHING 4 INCHES IN SPOTS /WHICH IS SUPPORTED BY THE NAM AND GFS BUFR DATA AS WELL AS THE COBB OUTPUT FROM THE BUFR DATA/. AFOREMENTIONED VORT MAX /CURRENTLY IN S CNTRL SODAK/ WILL ALSO TRAVERSE THIS AREA...WHICH WILL ENHANCE THE LIFT FROM ROUGHTLY RWF TO MSP TO RCX. N TO S ORIENTED CROSS SECTIONS THRU BOTH THE TWIN CITIES AND W CNTRL WI SHOW A 3 TO 6 HR PERIOD OF HIGH OMEGA VALUES...IN ADDITION TO A NEARLY VERTICAL AGEOSTROPHIC CIRCULATION. A FAIRLY DEEP LAYER OF NEGATIVE EPV ALSO EXISTS IN THE H5 TO H6 LAYER...ALONG WITH SPECIFIC HUMIDITIES OF 2 TO 3 G/KG IN THE SNOW PRODUCTION LAYER. NAM BUFR OUTPUT PAINTS THE BULLSEYE OF MAX OMEGA OCCURRING IN THE RGN OF MOST EFFICIENT SNOW GROWTH. WITH ALL THESE INGREDIENTS COMING TOGETHER...CONCERN EXISTS THAT A FEW AREAS /MAYBE A NARROW STRIPE/ MAY SEE TOTALS IN THE 4 TO 6 INCH RANGE. AS A RESULT...HAVE ELECTED TO ISSUE A SNOW ADVISORY FOR MAINLY E CNTRL MN AND W CNTRL WI. AFTER MIDNGT TNGT...MUCH OF THE PCPN THRU THE REMAINDER OF THE SHORT TERM SHUD REMAIN TO THE N OF THE FA AS A COUPLE OF UPR WAVES MOVE ACRS NRN MN AND INTO THE WRN GRTLKS...MAINLY ON SAT AND SAT NGT. HAVE PUT IN SOME FLURRIES ON SAT NGT ACRS W CNTRL WI. TEMP WISE...WARM AND MOIST PACIFIC AIR SHUD REMAIN OVER THE AREA...LEAVING TEMPS WELL ABOVE NORMAL. MANY THANKS TO ABR...DLH...ARX...AND FGF FOR THE COORD THIS MRNG. LONGER TERM...SUNDAY THROUGH THURSDAY THIS PERIOD IS EXPECTED TO FEATURE A GRADUAL WARMING TREND WITH NEAR OR ABOVE FREEZING TEMPERATURES FOR DAYTIME MAXES WITH MIN TEMPERATURES RANGING THROUGH THE TEENS. LATEST GFS AND ECMWF SHOW A BASIC WEST TO NORTHWEST FLOW WHICH SHOULD REFLECT MODIFIED PACIFIC AIR FORCED OVER THE NORTHERN ROCKIES AND ENDING UP OVER THE UPPER MIDWEST. HEAVY DUTY ARCTIC AIR IS DISPLACED WELL NORTHEAST OF OUR REGION DURING THIS PERIOD. IN SUMMARY...BASICALLY A MILD DRY PERIOD. $$ && .MPX WATCHES/WARNINGS/ADVISORIES... MN...SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR ANOKA-BENTON- CHISAGO-ISANTI-KANABEC-MILLE LACS-MORRISON-SHERBURNE- STEARNS-TODD-WASHINGTON-WRIGHT COUNTY(IES). WI...SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BARRON-POLK-RUSK COUNTY(IES). && $$ RJN mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1156 AM EST THU JAN 19 2006 .AVIATION (18Z-18Z)... SURFACE ANALYSIS SHOWS STRONG SOUTHERLY FLOW OVER TAF SITES AS LOW DEVELOPS OVER THE CENTRAL PLAINS. SATELLITE IMAGERY SHOWS AC HAS MOVED OFF TO THE NORTHEAST WITH STRATA CU DEVELOPING IN THE WARM AIR ADVECTION FROM SRN INDIANA INTO ARKANSAS. LATEST NAM SHOWS SOME LOW LEVEL CONVERGENCE IN THE IN THE SOUTHERLY FLOW WORKING ALL THE WAY UP INTO OHIO THIS AFT. THUS WILL GO WITH SCT-BKN CU DECK DEVELOPING. BEST STRATA CU DECK WILL DEVELOP TO THE NORTH AND WEST OF TAF SITES THIS AFT INTO THIS EVENING. ONCE DECK (MVFR) ROLES IN TONIGHT THEN IT WILL BE WITH US THROUGH FORECAST. CONCERN THAT CLOUD DECK WILL LOWER TO BELOW 2 KFT AROUND OR AFTER 12Z BUT WILL KEEP THE 2.5 KFT FOR NOW. ALSO THERE IS THE THREAT OF SOME LIGHT PRECIP AFTER 06Z BUT WILL LEAVE OUT AS IT SHOULDN'T RESTRICT VISIBILITY AND IT MAY BE MORE HIT AND MISS. TIPTON && .PREVIOUS DISCUSSION... (ISSUED 918 AM EST THU JAN 19 2006) SHORT TERM (REST OF TODAY)... SURFACE ANALYSIS SHOWS STRONG SOUTHERLY FLOW AHEAD OF A DEVELOPING LOW IN THE CENTRAL PLAINS. SATELLITE IMAGERY SHOWS BKN TO OVC AC DECK WORKING ACROSS REGION IN THE STRONG WARM AIR ADVECTION. MORNING SOUNDING SHOWS ~50KT AT 1000KFT AND LOTS OF DRY AIR IN THE LOWER PART OF THE ATMOSPHERE. HAVE UPDATED GRIDS AND ZONES TO LOWER TEMPS A DEGREE OR TWO. USING MORNING SOUNDING AND LOOKING AT LATEST NAM AND RUC IT LOOKS LIKE TEMPS ACROSS THE SOUTH WILL MAKE IT TO THE MID 50S WITH NORTHERN KENTUCKY SQUEAKING INTO THE UPPER 50S. WIND GUSTS LOOK GOOD FOR NOW BUT WILL MONITOR TO SEE IF THEY NEED TO BE BUMPED UP SINCE 50KTS IS NOT TO FAR OFF. TIPTON PREVIOUS DISCUSSION... (ISSUED 617 AM EST THU JAN 19 2006) AVIATION (12Z-12Z)... EXPECT TO SEE A CONTINUATION OF THE AC AND CIRRUS THROUGH THIS MORNING AS AREA OF MID LEVEL ISENTROPIC LIFT PUSHES ACROSS THE REGION. COULD SEE SOME CLEARING EARLY THIS AFTERNOON BEFORE BETTER ISENTROPIC LIFT DEVELOPS IN THE LOWER LEVELS LATE THIS AFTERNOON AND INTO TONIGHT. AS IT DOES...EXPECT SC DECK TO FORM ACROSS AREA AND SLOWLY LOWER INTO MVFR CONDITIONS OVERNIGHT. COULD EVEN SEE A FEW SPRINKLES OR LIGHT RAIN SHOWERS LATE IN THE TAF PERIOD BUT CHANCE APPEARS LOW ENOUGH TO LEAVE MENTION OUT OF TAFS ATTM. PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 410 AM EST THU JAN 19 2006 SHORT TERM (TODAY THROUGH SATURDAY)... CURRENT SURFACE ANALYSIS DEPICTS HIGH PRESSURE CENTERED OVER WEST VIRGINIA THIS MORNING WITH DEVELOPING LOW PRESSURE SYSTEM ACROSS THE CENTRAL PLAINS. WITH WAA KICKING IN...TEMPERATURES ARE SLOWLY RISING ACROSS THE REGION. REGION WILL EXPERIENCE ABOVE NORMAL TEMPERATURES TODAY (BY AS MUCH AS 20 DEGREES ABOVE NORMAL). WITH GOOD LOW LEVEL JET IN PLACE TODAY...COULD SEE SOME GUSTS TO 30 MPH. ISENTROPIC LIFT INCREASES OVERNIGHT INTO FRIDAY AHEAD LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS. GFS IS SLOWER THAN THE NAM WITH THE APPROACH OF THIS SYSTEM. HAVE SPEED UP CURRENT FORECAST POPS A BIT...BUT NOT AS QUICK AS THE NAM. HAVE HIGHEST POPS NEAR COLD FRONT WHICH LOOKS TO BE EAST OF CWA BY 12Z. HAVE ENDED ALL POPS BY SATURDAY AFTERNOON. FOR TEMPS...TODAY THRU FRIDAY...HAVE STUCK CLOSE TO MAV/MET NUMBERS...FWC NUMBERS SEEM TOO COLD. USED A BLEND REMAINDER OF FORECAST PERIOD. RLG LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... ONLY CHANCE TO EXTENDED WAS TO ADD PRECIP ON SUNDAY NIGHT AND MONDAY WITH APPROACH OF LOW PRESSURE SYSTEM FROM THE GULF REGION. PREVIOUS DISCUSSIONS FOLLOWS. (ISSUED 351 PM EST WED JAN 18 2006) EXTENDED MODELS ARE IN REASONABLE AGREEMENT IN THE EXTENDED WITH MORE VARIABILITY TOWARDS DAY 7. AT 500MB SOUTHWEST FLOW WILL DRIVE OUR WEATHER THROUGH THE EXTENDED. SATURDAY AN OPEN WAVE WILL RAPIDLY MOVE THROUGH THE OHIO VALLEY. ECMWF AND UKMET ARE A BIT FASTER THAN GFS BUT ALL SAME PATTERN. SUNDAY WILL BE DRY WITH HIGH PRESSURE. FOR MONDAY THE GFS IS BRINGING PRECIP BACK INTO FORECAST AREA AS IT DEVELOPS A LOW WHICH MOVES ACROSS THE TENNESSEE VALLEY. THE UKMET AND ECMWF DO NOT RESEMBLE THIS PATTERN. HOWEVER, DOING A DPROG/DT ON THE GFS IT HAS BEEN TRENDING TOWARD THIS SOLUTION FOR THE LAST 3 OR 4 RUNS. WILL NOT BUY OFF ON IT YET...HOWEVER WILL NOT IGNORE IT. THUS WILL GO WITH 25 POPS FOR MONDAY INTO MONDAY NIGHT. THE REST OF THE EXTENDED WILL BE DRY. TEMPERATURES THROUGH EXTENDED WILL REMAIN ABOVE NORMAL. TIPTON && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1204 PM CST THU JAN 19 2006 .UPDATE...BIGGEST CHANGE TO CURRENT DATA BASE WAS TO RAISE MAXIMUM TEMPERATURES FOR THIS AFTERNOON OVER MOST OF THE FORECAST AREA. BASED ON THIS...FORECAST SNOWFALL AMOUNTS WERE DECREASED FOR AREAS GENERALLY ALONG AND NORTH OF A LINE FROM KRST TO KMFI. STILL THINKING WIZ017 AND WIZ029 SHOULD RECEIVE ANOTHER ROUND OF SNOWFALL LOOKING AT REGIONAL RADAR DATA...AS WELL AS LATEST NAM AND RUC. && THOMPSON .PREV DISCUSSION... (ISSUED 1030 AM CST THU JAN 19 2006) UPDATE...LATEST RADAR TRENDS INDICATED BAND OF FREEZING RAIN...SLEET AND SNOW HAD SHIFTED NORTHWARD AND WILL CONTINUE TO DO SO THIS MORNING. THEREFORE...WINTER WEATHER ADVISORY CANCELLED FOR ALL EXCEPT WIZ029...CLARK CO...WHICH SHOULD BE ALLOWED TO EXPIRE ON TIME AT 18Z. REST OF THE FORECAST GENERALLY UNCHANGED. THOMPSON PREV DISCUSSION... (ISSUED 915 AM CST THU JAN 19 2006) UPDATE...BASED ON LATEST RADAR AND SURFACE OBSERVATIONS...A WINTRY MIX OF PRECIPITATION OCCURING THIS MORNING ACROSS NORTHERN PORTIONS OF THE FORECAST AREA. TELEPHONE CALLS TO LAW ENFORCEMENT OFFICIALS AND REPORTS FROM WEATHER OBSERVERS INDICATED ROADS WERE BECOMING SLIPPERY. THUS...HAVE ISSUED A WINTER WEATHER ADVISORY THROUGH NOON TODAY FOR AFOREMETIONED AREAS. PLEASE REFERENCES LATEST WINTER WEATHER STATEMENTS FOR FURTHER DETAILS. THOMPSON PREV DISCUSSION... (ISSUED 230 AM CST THU JAN 19 2006) SHORT TERM...TODAY THROUGH SATURDAY THE FORECAST FOCUS IN THE SHORT TERM IS TWO FOLD...FIRST ON A SHORTWAVE TO BRING PCPN TO REGION TODAY/TONIGHT...THEN A POTENTIAL WINTER STORM THAT MAY...OR MAY NOT...AFFECT PORTIONS OF THE LOCAL AREA ON FRI NIGHT/SAT. THE NAM AND GFS ARE IN BETTER AGREEMENT WITH A SHORTWAVE TO SPIN ACROSS THE UPPER MISSISSIPPI RIVER VALLEY TODAY...AS THE NAM COMES MORE INLINE WITH GFS. THIS 500 MB FEATURE WILL MOVE FROM THE PLAINS TO ACROSS NORTHERN WI TONIGHT...WITH AN ACCOMPANYING SFC LOW TRACKING INTO SOUTHERN WI BY THIS EVENING. QG CONVERGENCE ISN/T ALL THAT IMPRESSIVE...WITH THE BEST FORCING IN THE 700:SFC LAYERS EAST OF THE FORECAST AREA BY 18Z. THIS WOULDN/T HAVE HAD MUCH IMPACT THOUGH...AS THE DEEPEST SATURATION ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LOOKS TO BE NORTH OF THE SFC LOW...PER THE RH FIELDS AND TIME/HEIGHT X-SECTIONS. FN VECTORS IN THE 700:500 MB LAYER DOES INDICATE THE POTENTIAL FOR SOME BANDING...NORTHWEST OF THE LOW FROM CENTRAL MN INTO NORTHERN WI. THE DEFORMATION FIELDS AND OMEGA IN THIS SAME LAYER REVEALS SIMILAR FORCING/POTENTIAL. THE NAM ALSO POINTS TO SOME -EPV IN THE 700:600 MB LAYER...LOCATED NEAR THE SOUTHERN EDGE OF THE MODELED QPF...AND CO-LOCATED WITH SOME QG CONVERGENCE. THIS ALSO HINTS AT THE POTENTIAL FOR SOME ENHANCED BANDING. SO...WHAT AT FIRST LOOKED LIKE A RATHER INNOCUOUS SHORTWAVE TROUGH THAT COULD PRODUCE AROUND AN INCH OR TWO OF SNOW...SHOWS SOME PROMISE FOR A NARROW BAND OF SEVERAL INCHES HIGHER. TOUGH TO PINPOINT THAT...AS IT WILL LIKELY BE RATHER NARROW IF IT DEVELOPS...BUT THE MORE PROBABLE AREA FOR THE GREATER SNOW AMOUNTS CURRENTLY LOOKS TO BE ROUGHLY A CENTRAL MN...MSP...TO NORTHERN WI...PHILLIPS LINE. MORE LOCALLY...THE BEST SNOW CHANCES FOR TODAY SHOULD LIE FROM AN AUSTIN TO BLACK RIVER FALLS LINE...WITH THE BETTER ACCUMULATIONS NORTH OF NEILLSVILLE. ABOUT 2-4 INCHES LOOKS POSSIBLE IN THE FAR NORTHERN PARTS OF THE FORECAST AREA...WITH 1-2 SOUTH OF THERE. THE SNOW WILL CONTINUE TO SHIFT NORTHEAST AND EXIT THIS EVENING...AS THE WHOLE SYSTEM MOVES NORTHEAST INTO SOUTHERN CANADA. ON FRIDAY...A MUCH TALKED ABOUT DEVELOPING WINTER STORM WILL START MOVING OUT OF THE SOUTHERN PLAINS...WITH THE SFC LOW MOVING NORTHEAST THROUGH CENTRAL ILL FRI NIGHT. WHILE THE MODELS HAVE SETTLED ON THE TRACK...AND ARE CLOSER IN THEIR TIMING...THERE CONTINUES TO BE SOME VARIANCES IN HOW FAR NORTH/SOUTH THE LOW WILL GO. THE NAM IS SOUTH OF THE GFS...AND WOULD THEREFORE KEEP THE BRUNT OF ITS SNOW...IF NOT ALL OF ITS SNOW...SOUTH OF THE FORECAST AREA. AFTER HAVING MARKEDLY DIFFERENT TAKES ON THIS WINTER STORM...THE EC AND GFS HAVE COME INTO MORE AGREEMENT NOT ONLY WITH TRACK AND TIMING...BUT IN STRENGTH. THE GFS MIGHT BE A BIT TOO STRONG...BUT OVERALL LIKE ITS AND THE EC/S SOLUTION. THIS WOULD STILL KEEP THE BRUNT OF THIS WINTER STORM TO THE SOUTH...BUT THE NORTHERN EXTENT OF ITS PCPN WOULD EXTEND INTO THE SOUTHEASTERN 1/3 OF THE FORECAST AREA. STRONG QG CONVERGENCES AND ISENTROPIC UPGLIDE ACCOMPANIES THE SYSTEM...AS ONE WOULD EXPECT...BUT IT ALSO LIES MAINLY TO THE SOUTHEAST. SO...IT LOOKS LIKE THE FORECAST AREA WILL GET A GLANCING BLOW FROM THE WINTER STORM...ALTHOUGH THIS STILL COULD AMOUNT TO 1 TO 3 INCHES OF SNOW ACROSS THE FAR SOUTHEAST...MOSTLY SOUTH OF AN ELKADER TO MUSCODA LINE. THE SNOW SHOULD WRAP UP BEFORE SAT MORNING...AS THE SYSTEM MOVES OFF TOWARD THE NEW ENGLAND STATES. ANOTHER SHORTWAVE TROUGH WILL MOVE THROUGH THE NORTHERN STREAM...AND BEAR DOWN ON THE UPPER MISSISSIPPI RIVER VALLEY FOR SAT/SAT NIGHT. ITS CURRENT TRACK WOULD KEEP ITS BEST SNOW CHANCES TO THE NORTH. OVERALL...SNOW WILL SPREAD ACROSS MUCH OF THE AREA TODAY...ALTHOUGH NORTHEAST IA AND SOUTHWEST WI MIGHT BE HARD PRESSED FOR SOME FLURRIES. SOME SNOW ACCUMULATION IS LIKELY...WITH THE HIGHER AMOUNTS IN THE NORTH. A WINTER STORM WILL THEN PASS JUST SOUTHEAST OF THE FORECAST AREA ON FRI NIGHT/SAT...BUT SHOULD STILL BRING SOME SNOW TO THE FAR SOUTHEAST. LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY OVERALL...THE EXTENDED MODELS ARE IN FAIRLY GOOD AGREEMENT THIS GO AROUND...WITH THE DGEX BEING A BIT SLOWER AND FARTHER SOUTH WITH A SYSTEM ON MON/TUES...WHICH PROBABLY WOULDN/T IMPACT THE LOCAL AREA ANYWAY. AS THEY WERE YESTERDAY...THE MODELS HAVE LATCHED ON TO ONE STORM TRACK FOR THE BREWING WINTER STORM FOR FRI NIGHT/SAT...KICKING THE SFC LOW OUT ACROSS THE NEW ENGLAND STATES BY SAT NIGHT. A COUPLE 500 MB SHORTWAVE TROUGHS THEN LOOK TO TRACK THROUGH THE MISSISSIPPI RIVER VALLEY ON SUN NIGHT/MON...BUT CURRENTLY LOOK TO SPLIT THE LOCAL AREA. ONE WILL HOLD IN THE NORTHERN STREAM...AND MOVE ACROSS NORTHERN MN/WI...WHILE THE OTHER LOOKS TO TAKE A SIMILAR TRACK TO THE SAT SYSTEM...MOVING NORTHEAST ACROSS THE OH RIVER VALLEY. THIS WOULD KEEP THE BRUNT OF BOTH SYSTEMS EITHER NORTH OF SOUTH OF THE FORECAST AREA. YET ANOTHER SHORTWAVE WOULD DROP BEHIND THE NORTHERN SYSTEM...SPINNING ACROSS THE NORTHERN/EASTERN GREAT LAKES TUES/TUES NIGHT. AGAIN THOUGH...THE MODELS WOULD KEEP THE BETTER PCPN CHANCES AWAY FROM THE LOCAL AREA. SO...FAIRLY ACTIVE WEATHER EXPECTED FOR THE WEEKEND INTO THE EARLY PART OF NEXT WEEK...IT JUST CURRENTLY LOOKS AS IF THESE SYSTEMS WILL KEEP THE PCPN CHANCES AWAY FROM THE LOCAL AREA. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ THOMPSON wi