Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 02/17/07

AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
200 PM PST THU FEB 15 2007 .SYNOPSIS... HIGH PRESSURE OFF THE CALIFORNIA COAST AND WEAK OFFSHORE FLOW WILL BRING FAIR AND MUCH WARMER WEATHER THROUGH SATURDAY. LOCALLY BREEZY AT TIMES THROUGH SATURDAY...MAINLY THROUGH AND BELOW MOUNTAIN CANYONS AND PASSES. WEAK UPPER LEVEL LOW PRESSURE PASSING BY TO THE SOUTHEAST WILL CAUSE INCREASING CLOUDINESS LATE SATURDAY AND SUNDAY ALONG WITH COOLING SUNDAY. STRONGER LOW PRESSURE FROM THE NORTHWEST WILL BRING MORE CLOUDS AND COOLING WITH A CHANCE OF SHOWERS EARLY NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... LATE MORNING ACARS SOUNDING OUT OF KSAN INDICATED THE MARINE LAYER HAD LOWERED TO AROUND 250 FEET SINCE THIS MORNING. WIND DIRECTION AT KSAN SUGGESTS A WEAK EDDY WAS OVER THE COASTAL WATERS AS WELL. RIDGING OVER THE EASTERN PACIFIC IS EXPECTED TO PUSH CLOSER TO THE COAST THROUGH FRIDAY THEN MOVE OVER THE COAST ON SATURDAY. WEAK OFFSHORE FLOW IS EXPECTED TO CONTINUE THROUGH SATURDAY AS WELL. THE COMBINATION OF WEAK OFFSHORE FLOW AND A STRONG RIDGE SHOULD BRING SOME WARMING TO MOST AREAS THROUGH SATURDAY. SOME GUSTY NORTHEAST WINDS ARE EXPECTED THROUGH AND BELOW MOUNTAIN PASSES AND CANYONS BUT WINDS SHOULD REMAIN BELOW WIND ADVISORY LEVELS. ANOTHER TROUGH OF LOW PRESSURE IS EXPECTED TO MOVE CLOSER TO THE COAST ON SUNDAY THEN OVER THE COAST SUNDAY NIGHT INTO MONDAY MORNING. THE LATEST GFS MODELS INDICATE THIS SHORTWAVE SHOULD MOVE THROUGH FAIRLY QUICKLY WITH MOST OF THE SHORTWAVE OUT OF THE AREA BY TUESDAY NIGHT. THIS WOULD SUGGEST THAT MONDAY NIGHT AND TUESDAY SHOULD BE DRYING OUT. WILL LEAVE THIS TO THE NEXT SHIFT TO DECIDE ON SINCE IT IS DURING THE EXTENDED PERIOD. ALSO APPEARS A STRONGER SHORTWAVE WILL MOVE INTO THE AREA LATE IN THE WEEK. && .AVIATION... IT WILL REMAIN CLEAR THROUGH FRIDAY. OFFSHORE FLOW INCREASES FRIDAY MORNING WITH LOCAL GUSTY NE WINDS TO 25 MPH THROUGH PASSES. WINDS AT 5K FT...NORTH TO NORTHEAST 10-15 KT THROUGH FRIDAY AFTERNOON. WINDS AT 10K FT...NORTHEAST 25-35 KT THIS AFTERNOON...THEN NORTHEAST 15-25 KT TONIGHT THROUGH FRIDAY AFTERNOON. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...HORTON AVIATION/MARINE...MACHECKNIE NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
429 PM EST THU FEB 15 2007 .SHORT TERM... TONIGHT AND FRIDAY...HAVE ISSUED A WIND CHILL ADVISORY FOR MUCH OF NORTHERN INDIANA AND NORTHWEST OHIO...EXCEPT FOR AREAS NEAR THE MICHIGAN STATE LINE. THE CORE OF ARCTIC AIR IS EXPECTED TO MOVE ACROSS THE AREA TONIGHT AS SKIES BECOME CLEAR/MOSTLY CLEAR EXCEPT FOR FAR SOUTHERN LOWER MICHIGAN AND BORDERING AREAS TO THE SOUTH. PER ACARS/TAMDAR OBS...NAM/WRF HAS INITIALIZED THE UPSTREAM CORE WELL WITH 925 MB TEMPS BETWEEN -18C AND -19C...WHICH WAS EVEN COLDER THAN THE AIRMASS OVER THE AREA THIS MORNING WHEN FWA...DFI AND GUS DROPPED TO BETWEEN -8F AND -12F. SNOW DEPTHS STILL 8 INCHES TO CLOSE TO 2 FEET OVER THE SOUTHERN HALF OF THE AREA...SOUTH OF HIGHWAY 6...AND SUFFICIENT FOR EVEN RECORD COLD LOWS IF CONDITIONS ARE RIGHT. WINDS SHOULD STAY UP ENOUGH TO CAUSE WIND CHILL TEMPERATURES TO FALL TO BETWEEN -20F AND -25F TONIGHT INTO FRIDAY MORNING. NCEP GFS/MAV AND NGM/FWC MOS NOT HANDLING LOWS VERY WELL...POSTING A LARGE WARM BIAS OF AS MUCH AS 17F. NEEDLESS TO SAY...CUT MOS TEMPS SIGNIFICANTLY. CONDITIONS WILL STILL BE CHILLY FRIDAY MORNING AS RETURN FLOW INCREASES...BUT WARM AIR ADVECTION JUST BEGINNING. && .LONG TERM... FRIDAY NIGHT THROUGH THURSDAY. UPR LVL WEATHER PATTERN OVER THE UNITED STATES AND CANADA WILL UNDERGO A PATTERN SHIFT DURING THE EXTENDED PERIOD. COLD POLAR VORTEX LOCATED OVER SE CANADA AND PREDOMINATE NORTHWEST FLOW WILL GRADUALLY WEAKEN AND SHIFT NORTHWARD BY EARLY NEXT WEEK. IN THE MEANTIME...THERE WILL BE A CLIPPER SYSTEM TO CONTEND WITH IN THE IMMEDIATE LONG TERM PERIOD...AS WELL AS ANOTHER ROUND OF LAKE EFFECT SNOW IN ITS WAKE. PREFER THE 12Z GFS VERSUS THE NAM-WRF IN REGARDS TO THE UPCOMING CLIPPER SYSTEM AND WILL THUS USE CLOSELY. MID LVL S/WV WAS PUSHING ONSHORE ACRS BRITISH COLUMBIA THIS AFTN. THIS FEATURE WILL DIVE RAPIDLY SE INTO THE NRN PLAINS ON FRIDAY...THEN IT WILL HEAD TOWARD THE WRN GREAT LAKES/LOWER OHIO VALLEY FRIDAY NIGHT. DECENT ISENTROPIC LIFT/WAA AHEAD OF THE CLIPPER WILL BRING A SWATH OF SNOW TO THE REGION...BEGINNING FRIDAY EVENING AND CONTINUING INTO SATURDAY MORNING. THERE WILL ALSO BE SOME DYNAMICAL LIFT WITH THE UPR LVL S/WV...AIDING IN UPWARD VERTICAL MOTION. THE MODIFIED GARCIA METHOD AND MODEL QPF INDICATE THAT 2 TO 4 INCHES OF SNOW WILL FALL ACROSS THE REGION FROM FRIDAY NIGHT INTO SATURDAY MORNING. AS THE CLIPPER PASSES TO THE SE BY SATURDAY AFTERNOON...SNOW WILL TAPER OFF. TEMPERATURES FRIDAY NIGHT WILL BE NON DIURNAL AS WAA AND WINDS FROM THE SOUTH/SOUTHWEST ALLOW TEMPS TO RISE SLOWLY TOWARD SATURDAY MORNING. THUS...WILL GO WITH AN EARLY EVENING LOW IN THE MID TEENS WITH TEMPS WARMING TO THE UPPER TEENS TO LOWER 20S BY SATURDAY MORNING. HIGHS ON SATURDAY WILL WARM INTO THE UPPER 20S. FOR SATURDAY NIGHT INTO SUNDAY NIGHT...ONE MORE S/WV WILL DIVE SE OUT OF CENTRAL CANADA INTO THE GREAT LAKES REGION. THIS FEATURE WILL BRING A BRIEF REINFORCING SHOT OF ARCTIC AIR. THE COLD AIR MOVING ACRS THE RELATIVELY WARMER WATERS OF LAKE MICHIGAN WILL GENERATE LAKE EFFECT SNOW SHOWERS. CURRENT FORECAST FETCH OF 300 TO 320 IS EXPECTED. HAVE MAINTAINED CURRENT HIGH CHC POPS IN THE FAVORED LAKE EFFECT COUNTIES FOR SATURDAY NIGHT...AND HAVE EXTENDED THE HIGH CHC INTO SUNDAY. LAKE EFFECT SNOW SHOWERS WILL DIMINISH QUICKLY SUNDAY NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS TOWARD THE REGION. TEMPERATURES WILL REMAIN MUCH BELOW NORMAL DURING THIS PERIOD. AS STATED BEFORE...A PATTERN SHIFT IS IN THE OFFING FOR NEXT WEEK. S/WV ACTIVITY WILL COME ONSHORE ACRS THE WEST COAST...AND WILL TAKE A SRN TRAJECTORY ACRS THE SRN UNITED STATES. MEANWHILE...SOME S/WV ENERGY IN THE NRN JET STREAM (A SPLIT FLOW PATTERN) WILL PUSH A COLD FRONT THROUGH THE REGION TUESDAY/TUESDAY NIGHT. MODELS HAVE BEEN INCONSISTENT WITH THE SRN STREAM S/WV ENERGY...OSCILLATING ITS POSITION FROM RUN TO RUN. THE PATTERN THIS WINTER HAS BEEN TO TAKE THESE SRN STREAM S/WVS END FARTHER NORTH THAN FORECAST. MUCH UNCERTAINTY AT THIS POINT...SO WILL WAIT TO SEE HOW THIS ONE PANS OUT. IN THE MEANTIME...WILL JUST FOCUS ON THE NRN STREAM S/WV AND ASSOCD COLD FRONT TUESDAY/TUESDAY NIGHT. PCPN TYPE WILL BE A CONCERN AS TEMPS WILL WARM TO SLIGHTLY ABOVE FREEZING. WILL GO WITH A CHC OF RAIN OR SNOW ON TUESDAY...WITH A CHC OF SNOW TUESDAY NIGHT IN THE WAKE OF THE FRONT. HIGH PRESSURE IS FCST SETTLE ACRS THE FCST REGION WEDNESDAY AND THURSDAY. WILL FCST PARTLY CLOUDY SKIES WITH TEMPS AT OR SLIGHTLY ABOVE NORMAL. && .AVIATION... LAKE EFFECT SNOW SHOWERS SHOULD TRANSLATE EAST OF SBN THIS AFTERNOON...LEAVING MAINLY CLEAR TO PARTLY CLOUDY SKIES AS HIGH PRESSURE BUILDS INTO THE AREA. CONDITIONS SHOULD BECOME VFR. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND CHILL ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO 11 AM EST /10 AM CST/ FRIDAY FOR INZ008-009-012>018-020- 022>027-032>034. MI...NONE. OH...WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 11 AM EST FRIDAY FOR OHZ004-005-015-016-024-025. LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR LMZ043-046. && $$ SHORT TERM/AVIATION...SKIPPER LONG TERM....HICKMAN
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
230 PM EST THU FEB 15 2007 .SHORT TERM (TONIGHT-FRIDAY)... MAIN FOCUS IN THE SHORT TERM WILL BE OVER THE NEXT 6-9 HOURS. RADAR SHOWING SOMEWHAT WIDESPREAD FLURRY OR -SHSN ACTIVITY DEVELOPING FROM ROUGHLY HOP-SDF-CVG AS OF 18Z. LAPSE RATES ARE VERY STEEP ON LATEST ACARS SOUNDINGS AT SDF (THROUGH THE -15C LEVEL)...BUT LOW LEVELS ARE QUITE DRY. BEST CHANCES FOR -SHSN WILL BE ALONG RELATIVE MAX IN SFC DEWPOINTS...WHICH CURRENTLY STRETCHES FROM WRN KY UP INTO THE SDF-CVG CORRIDOR. GFS LOW LEVEL RH FIELDS PICK UP ON THIS ENHANCED CLOUDINESS AT THE 900/925MB LEVELS...AND TRANSLATE FEATURE SE INTO OUR ERN COUNTIES BY 22-00Z THIS EVENING...AND OUT OF THE CWA SHORTLY THEREAFTER. WILL INCLUDE A "LATE AFTERNOON" PERIOD IN THE ZONES FOR ISLTD -SHSN. NOT EXPECTING ANY ACCUMS OTHER THAN TRACE GIVEN THE RELATIVELY DRY LOW LEVELS. CLOUD COVER TONIGHT WILL PRESENT A CHALLENGE...WITH NAM DEVELOPING WIDESPREAD LOW STRATUS WHILE GFS IS SIGNIFICANTLY DRIER IN THE LOW LEVELS. FEEL THAT NAM IS OVERDEVELOPING LOW STRATUS THIS AFTN OVER THE SNOW FIELDS NORTH OF THE CWA...WHICH IS SEEN IN THE 6-9HR VERIFICATIONS OF THE 12Z RUN...SO WILL SIDE WITH GFS. WILL STILL MAINTAIN AT LEAST 30% CLOUD COVER OVERNIGHT WITH BANDS OF MID/HIGH LEVEL CLOUDS PASSING THROUGH. LOWS TONIGHT WILL BE VERY COLD OVER THE N 1/3 OF THE DISTRICT...MID-UPPER SINGLE DIGITS. WIND CHILLS WILL LIKELY DROP INTO THE -5 TO -10F RANGE BY DAYBREAK...SO WILL HIGHLIGHT THIS IN HAZ WX OUTLOOK SINCE IT IS BORDERLINE ADVISORY CRITERIA. OVER SRN KY...WCI VALUES SHOULD BE WARMER (~ZERO TO 5 ABOVE). SIG WX NIL DURING THE DAYLIGHT HOURS FRIDAY WITH LOW LEVEL FLOW TURNING MORE SOUTHERLY TOWARD LATE AFTN AHEAD OF APPROACHING CLIPPER. SIGNIFICANT THERMAL TROF REMAINS OVER THE CWA...AND EVEN WITH EXPECTED SUNSHINE...TEMPS WILL ONLY BE A FEW DEGREES WARMER THAN TODAY. CS .LONG TERM (FRIDAY NIGHT-THURSDAY)... ...CLIPPER SYSTEM TO BRING A PERIOD OF SNOW TO THE REGION LATE FRIDAY AND SATURDAY... FRIDAY NIGHT THROUGH SUNDAY NIGHT... OVERALL...SHORT TERM MODEL SOLUTIONS ARE COMING INTO SOMEWHAT BETTER AGREEMENT WITH THIS WEEKENDS CLIPPER SYSTEM. 12Z NAM-WRF AND GFS CONTINUE TO SHOW UPPER LEVEL WAVE AND ASSOCIATED SFC LOW TRACKING SOUTHEAST TOWARD THE OHIO VALLEY. THOUGH AS THE SFC LOW GETS HERE...IT WILL BE WEAKENING. GFS AND NAM CONTINUE TO DIFFER ON THE FORECAST TRACK OF THE SYSTEM WITH THE NAM TAKING THE LOW NORTH OF THE RIVER WITH THE GFS A BIT FURTHER SOUTH. THE GFS TIMING IS FASTER THAN THE NAM WHICH WOULD KEEP MUCH OF THE HEAVIEST PRECIPITATION FALLING DURING THE DAY ON SATURDAY. THERMAL PROFILES HAVE TRENDED COLDER OVER THE LAST FEW RUNS AND OVERALL PROFILES SUGGEST SNOW AS THE PREDOMINANT PRECIPITATION. MAIN FORECAST CHALLENGE HERE WHAT WILL BE THE OVERALL TRACK OF THE SYSTEM. SO FAR THIS SEASON...THE NAM HAS OUTPERFORMED THE GFS SOLUTION HANDS DOWN. THE QPF VALUES HAVE BEEN MORE REALISTIC AS WELL AS THE THERMAL PROFILES. THE GFS HAS ALSO TENDED TO BE COLDER AND MORE WET IN TERMS OF QPF. AT THIS TIME...I THINK THE BEST APPROACH WOULD BE TO GO WITH A BLEND OF BOTH MODELS BUT CLOSER TO THE NAM SOLUTION. QPF AMOUNTS THROUGH THE ENTIRE EVENT WILL BE LESS THAN 0.25 INCHES AND WITH EXPECTED WARMTH IN THE PBL DURING THE DAY ON SATURDAY...SNOW RATIOS WILL BE CLOSE TO CLIMO WHICH IS 12:1. SNOW AMOUNTS FROM THE NAM WOULD SUGGEST 1-2 INCHES WHILE THE GFS SUGGESTS 2-4 INCHES. FOR NOW WILL PLAN ON A GENERAL 1-3...BUT MOST LOCATIONS WOULD LIKELY SEE 1-2 INCHES. IF THE SYSTEM TRENDS FURTHER NORTH...LESS SNOW IS LIKELY. TEMPERATURES SATURDAY WILL START OFF COLD WITH OVERNIGHT LOWS IN THE UPPER TEENS TO THE LOWER 20S. STUCK CLOSER THE THE 2M GFS NUMBERS FOR SATURDAY AFTERNOON WITH HIGHS IN THE UPPER 20S TO AROUND 32. AS CLIPPER SYSTEM MOVES EAST...DEEP NORTHWEST FLOW WILL CONTINUE ACROSS THE REGION. WEAK STATIC STABILITY AND LEFT OVER MOISTURE WILL LIKELY PRODUCE SCT SNOW SHOWERS DURING THE DAY ON SUNDAY ACROSS THE NORTHEAST THIRD OF THE FA. FOR THAT REASON HAVE OPTED TO KEEP LOW CHC POPS IN THE FORECAST HERE. TEMPERATURES WILL REMAIN WELL BELOW NORMAL WITH HIGHS IN THE LOW TO MID 20S IN THE NORTH TO THE UPPER 20S IN THE SOUTH. AS HIGH PRESSURE BUILDS IN...SKIES SHOULD CLEAR OUT SUNDAY NIGHT AND TEMPS WILL RAPIDLY COOL. TEMPS MONDAY MORNING WILL BE HIGHLY DEPENDENT ON SNOW COVER. SINCE WE FEEL WE`LL HAVE SOME SNOW ON THE GROUND...LOWS IN THE UPPER SINGLE DIGITS WILL BE POSSIBLE ACROSS THE NORTHEAST SECTIONS WITH MID TEENS ACROSS THE SOUTHWEST. MONDAY THROUGH THURSDAY... EXTENDED MODEL SOLUTIONS CONTINUE TO SHOW A GENERAL MODERATION IN TEMPERATURES OVER THE UPCOMING WEEK. SFC HIGH PRESSURE IS FORECAST TO MOVE EAST OF THE REGION BY LATE MONDAY ALLOWING DEEP SOUTHWESTERLY FLOW TO RETURN TO THE REGION. COMBINATION OF DEEP SW FLOW COMING OFF THE GULF SHOULD RESULT IN SOME SCT LIGHT PRECIPITATION BY TUESDAY. INITIAL PRECIP MAY BE MIXED OR SNOW...BUT WOULD QUICKLY CHANGE TO RAIN AS TEMPS WARM. 00Z GFS ENSEMBLE SOLUTIONS SUPPORT THIS AND CURRENT FCST HAS THIS COVERED WELL. LATEST 12Z GFS HAS TRENDED MORE SOUTHERLY WITH SFC CYCLONE GOING ACROSS THE GULF COAST STATES. THIS IS IN STARK CONTRAST TO THE 06Z GFS RUN. GIVEN THE RATHER POOR RUN TO RUN CONSISTENCY GENERALLY PLAN ON STICKING CLOSE TO THE 00Z GFS ENSEMBLE PACKAGE FOR THIS PERIOD. ENSEMBLE PACKAGE IS A BIT FURTHER NORTH WITH SFC LOW GOING ACROSS THE SOUTHERN STATES. NET RESULT IS A CHANCE OF PRECIPITATION ON WEDNESDAY WITH DRIER CONDITIONS RETURNING BY THU. THERMAL PROFILES SUGGEST PRECIP ON WED WILL BE RAIN AS OVERALL ARCTIC PATTERN LOOSES ITS GRIP ON THE EASTERN THIRD OF THE COUNTRY. -MJ && .AVIATION (18Z TAFS)... PRIMARY CHALLENGE FOR THE TAFS THIS AFTERNOON WILL BE COVERAGE OF LOW STRATUS. RECENT VISIBLE SATELLITE IMAGERY IS SHOWING WIDESPREAD STRATUS (~2-3KFT AGL) DEVELOPING ALONG AND WEST OF A FFT-BWG LINE. THIS WAS CAPTURED WELL IN THE 12Z NAM LOW LEVEL RH FCSTS...WHICH SHOW STATUS DEVELOPING/ADVECTING SE THROUGH LATE AFTERNOON WITHIN PREVAILING NW BOUNDARY LAYER FLOW. RADAR IS SHOWING SOME VERY WEAK RETURNS WITHIN LOW CLOUDS...SO A FEW FLURRIES ARE POSSIBLE BUT NOTHING EXPECTED AT THIS TIME THAT WOULD RESTRICT VSBYS BELOW 7SM. INTO TONIGHT...LAST NAM FCST SOUNDINGS SHOW THAT STRATUS WOULD BUILD DOWN INTO A SUPER LOW CEILING...HOWEVER GFS IS LESS PESSIMISTIC AS IS MOS GUIDANCE. WILL SIDE WITH THE LATER GROUP...BUT MENTION SOME SCT CLOUDS BELOW 1KFT AGL IN THE EVENT THAT THE NAM VERIFIES. CS && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
110 PM EST THU FEB 15 2007 .UPDATE... QUICK EARLY AFTERNOON UPDATE TO ACCOUNT FOR MORE WIDESPREAD FLURRY OR -SHSN ACTIVITY THAN EARLIER EXPECTED. LAPSE RATES ARE VERY STEEP ON LATEST ACARS SOUNDINGS AT SDF (THROUGH THE -15C LEVEL)...BUT LOW LEVELS ARE QUITE DRY. BEST CHANCES FOR -SHSN WILL BE ALONG RELATIVE MAX IN SFC DEWPOINTS...WHICH CURRENTLY STRETCHES FROM WRN KY UP INTO THE SDF-CVG CORRIDOR. CS && .SHORT TERM (TODAY AND TONIGHT)... UPPER TROUGH MOVING ESE ACROSS FA TODAY WILL BE ACCOMPANIED BY BKN TO OVC MID LEVEL CLOUDS WITH PERHAPS SOME SCT TO BKN SC UNDERNEATH...BOTH CLEARING OUT TONIGHT. UPSTREAM RADARS FROM KS...MO...AND IA DO SHOW SOME LIGHT RETURNS FROM THIS MID DECK BUT THAT PCPN LOOKS MOSTLY TO BE ALOFT. WITH VERY DRY AIR IN PLACE...DID NOT FEEL THAT IT REALLY IS WORTH MENTIONING ANY CHANCE OF FLURRIES AT THIS TIME. BUT TEMPS SHOULD BE A BIT COOLER TODAY...PARTLY IN RESPONSE TO THE INCREASED CLOUDINESS. FOR TONIGHT MIN TEMPS A FEW DEGS COOLER WITH CLEARING SKIES AND LIGHT WINDS GIVING RISE TO GOOD RADIATIONAL COOLING. SO MIN TEMPS 8 TO 10 DEGS N TO 12 TO 14 DEGS NEAR TN BORDER. --21 .LONG TERM (FRIDAY-WEDNESDAY)... SURFACE HIGH WILL BUILD EAST ACROSS THE GULF COAST STATES AND EXTEND NORTH INTO KENTUCKY ON FRIDAY...PROVIDING A SLIGHT WARM UP FROM THE VERY COLD TEMPERATURES. HIGHS ON FRIDAY WILL BE ABOUT 5 DEGREES WARMER THAN TODAY. HOWEVER NEXT COLD FRONT WILL BE DROPPING SOUTHEAST ACROSS THE UPPER PLAINS AND HEADING TOWARD THE LOWER OHIO VALLEY FRIDAY AND FRIDAY NIGHT. MAIN CHALLENGES THIS FORECAST WILL BE TIMING THE FRONT THROUGH AND WHETHER TEMPERATURES WILL BE WARM ENOUGH FOR ANYTHING BUT SNOW ON SATURDAY. HPC PREFERS ECMWF FOR THIS SYSTEM AND WILL GENERALLY FOLLOW 14/12Z ECMWF FOR TIMING THIS SYSTEM. NAM SEEMS TOO SLOW WHILE HPC POINTS OUT THAT GFS IS A LITTLE DEEP WITH H5 TROUGH ALTHOUGH TIMING OF ONSET OF PRECIPITATION IS SIMILAR TO ECMWF AND UKMET. THIS WILL BRING SNOW INTO INTO CENTRAL KENTUCKY BY MORNING WITH MOST OF SNOWFALL OCCURRING DURING THE MORNING AND EARLY AFTERNOON HOURS. LOOKS LIKE 1 TO 1 1/2 INCHES WEST AND 1 TO 2 INCHES OVER THE EAST. UKMET SOUNDING KEEPS TEMPERATURES COOL ENOUGH FOR SNOW DURING THE DAY SATURDAY EVEN ACROSS THE SOUTH. HOWEVER FORECAST HIGHS MAY ALLOW SOME MELTING AS THE PRECIPITATION FALLS. WILL LEAVE SNOW OR RAIN IN FORECAST IN THE SOUTH FOR NOW. SNOW WILL END ACROSS THE AREA SATURDAY NIGHT WITH DRY WEATHER FOR SUNDAY THROUGH MONDAY. ANOTHER SYSTEM MOVES IN FOR THE MIDDLE OF THE WEEK. HAVE NOT MADE ANY SIGNIFICANT CHANGES FOR THIS SYSTEM. SCHOLZ && .AVIATION (18Z TAFS)... PRIMARY CHALLENGE FOR THE TAFS THIS AFTERNOON WILL BE COVERAGE OF LOW STRATUS. RECENT VISIBLE SATELLITE IMAGERY IS SHOWING WIDESPREAD STRATUS (~2-3KFT AGL) DEVELOPING ALONG AND WEST OF A FFT-BWG LINE. THIS WAS CAPTURED WELL IN THE 12Z NAM LOW LEVEL RH FCSTS...WHICH SHOW STATUS DEVELOPING/ADVECTING SE THROUGH LATE AFTERNOON WITHIN PREVAILING NW BOUNDARY LAYER FLOW. RADAR IS SHOWING SOME VERY WEAK RETURNS WITHIN LOW CLOUDS...SO A FEW FLURRIES ARE POSSIBLE BUT NOTHING EXPECTED AT THIS TIME THAT WOULD RESTRICT VSBYS BELOW 7SM. INTO TONIGHT...LAST NAM FCST SOUNDINGS SHOW THAT STRATUS WOULD BUILD DOWN INTO A SUPER LOW CEILING...HOWEVER GFS IS LESS PESSIMISTIC AS IS MOS GUIDANCE. WILL SIDE WITH THE LATER GROUP...BUT MENTION SOME SCT CLOUDS BELOW 1KFT AGL IN THE EVENT THAT THE NAM VERIFIES. CS && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
915 AM EST THU FEB 15 2007 .SHORT TERM /THIS AFTN/... DOING AN EARLY PCKG TO EXP THE ADVSRY. METEOROLOGICALLY TDA A NICE RESPITE AFTR THE PAST FEW. HV TAKEN DOWN WIND CHILL ADVSRY. SNSH HV TAPERED OFF IN THE WRN HIGHLANDS. BRZY AND COOL THIS AFTN. WOODY! && .PREV DISCUSSION... /ISSUED 335 AM EST THU FEB 15 2007/ SHORT TERM (TODAY)... WATER VAPOR LOOP SHOWS THE UPPER LEVEL REFLECTION OF THE WINTER STORM IS MOVING OUT OF NEW ENGLAND. AN UPPER LOW IS SLIDING EAST INTO QUEBEC...AS THE NEXT SHORT WAVE DROPS THROUGH THE PLAINS. ACARS 400-250MB WIND OBSERVATIONS SHOW A 175-200KT WESTERLY JET ACROSS THE GULF STATES. 04Z SURFACE ANALYSIS PLACED A 975MB OCCLUDED CYCLONE ALONG THE MAINE COAST. A COLD FRONT EXTENDED WEST THROUGH THE GULF STATES...WITH A 1038MB ANTICYCLONE SPRAWLED ACROSS THE UPPER MIDWEST. MID AND UPPER LEVEL CLOUDS ARE DEVELOPING OVERHEAD ALONG THE UPPER LEVEL JET AXIS. WHILE THE BEST OF THIS MOISTURE SHOULD SHUNT TO THE NORTHEAST THIS MORNING...SOME MID AND UPPER LEVEL CLOUDS ARE EXPECTED TO REMAIN OVERHEAD THROUGH THE AFTERNOON. MEANWHILE...UPSLOPE SNOW SHOWERS WILL DIMINISH TODAY WITH WARM ADVECTION AHEAD OF THE NEXT PAIR OF SHORT WAVES. GRADIENT WILL CONTINUE TO SUPPORT GUSTY WINDS...WITH WIND CHILLS THIS MORNING REMAINING IN THE NEGATIVE 5 TO 10 DEGREE RANGE WHERE THE ADVISORY REMAINS IN EFFECT. DESPITE CONTINUED COLD ADVECTION...TEMPERATURES SHOULD SURPASS 30F (WITH ONLY A SLOW RISE IN THE HIGHER TERRAIN). WIND CHILLS MAY DROP TO SIMILAR LEVELS OVERNIGHT IN THE MOUNTAINS WITH GUSTY WINDS REMAINING ABOVE 2500 FT. DECOUPLING IN THE LOWER TERRAIN WILL ALLOW TEMPERATURES TO DIP THROUGH THE TEENS. ANY REMAINING MID AND UPPER LEVEL MOISTURE ASSOCIATED WITH THE JET AXIS SHOULD BE SHUNTED TO THE SOUTHEAST OVERNIGHT...HOWEVER THE ARRIVAL OF A PAIR OF SHORTWAVES MAY PRODUCE ANOTHER AREA OF MID LEVEL MOISTURE FROM THE WEST. UPSLOPE SNOW SHOWERS ARE EXPECTED TO REDEVELOP AND INTENSIFY DURING THE OVERNIGHT HOURS AS THE SHORT WAVES PASS OVERHEAD. LONG TERM... UPSLOPE SNOW SHOWERS WILL COME TO AN END FRIDAY MORNING ALONG AND WEST OF THE ALLEGHENY FRONT. HIGH PRESSURE MOVES ACROSS THE SOUTHEAST CONUS FRIDAY AND FRIDAY NIGHT...ALLOWING COLD NORTHWEST WINDS ON FRIDAY TO SWING AROUND TO THE SOUTHWEST BY SATURDAY. THE NEXT WEATHER MAKER WILL MOVE THROUGH THE OHIO VALLEY ON SATURDAY...AND ACROSS THE MID ATLANTIC SATURDAY NIGHT INTO EARLY SUNDAY. THIS WEAK CLIPPER TYPE SYSTEM WILL BRING A CHANCE OF SNOW SHOWERS. IN THE WAKE OF THE CLIPPER...UPSLOPE SNOW SHOWERS WILL OCCUR OVER THE HIGHLANDS THROUGH THE REST OF THE WEEKEND. ZONAL FLOW DEVELOPS EARLY NEXT WEEK...AND THE MODELS SHOW HEIGHTS AND THICKNESSES RISING TO LEVELS THAT WOULD FAVOR TEMPERATURES CLOSER TO CLIMATOLOGY. AVIATION... VFR CONDS TDA. GRADIENT WILL SUPPORT WIND GUSTS AROUND 20KTS. MARINE... PROXIMITY NAM/GFS BUFKIT FORECAST SOUNDINGS INDICATE 20-25KT WIND GUST POTENTIAL THROUGH TONIGHT. ICE COVERAGE ACROSS THE EXTREME NORTHERN BAY IS CLOSE TO 7-9 TENTHS. SMALL CRAFT ADVISORY WIND SPEEDS WILL CONTINUE ON FRIDAY...HOWEVER EXCEPT A QUICK REDUCTION IN WIND SPEEDS FRIDAY EVENING WITH DECOUPLING. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST FRIDAY FOR ANZ530>534. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ535>537. SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EST FRIDAY FOR ANZ535>537. && $$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
335 AM EST THU FEB 15 2007 .SHORT TERM (TODAY)... WATER VAPOR LOOP SHOWS THE UPPER LEVEL REFLECTION OF THE WINTER STORM IS MOVING OUT OF NEW ENGLAND. AN UPPER LOW IS SLIDING EAST INTO QUEBEC...AS THE NEXT SHORT WAVE DROPS THROUGH THE PLAINS. ACARS 400-250MB WIND OBSERVATIONS SHOW A 175-200KT WESTERLY JET ACROSS THE GULF STATES. 04Z SURFACE ANALYSIS PLACED A 975MB OCCLUDED CYCLONE ALONG THE MAINE COAST. A COLD FRONT EXTENDED WEST THROUGH THE GULF STATES...WITH A 1038MB ANTICYCLONE SPRAWLED ACROSS THE UPPER MIDWEST. MID AND UPPER LEVEL CLOUDS ARE DEVELOPING OVERHEAD ALONG THE UPPER LEVEL JET AXIS. WHILE THE BEST OF THIS MOISTURE SHOULD SHUNT TO THE NORTHEAST THIS MORNING...SOME MID AND UPPER LEVEL CLOUDS ARE EXPECTED TO REMAIN OVERHEAD THROUGH THE AFTERNOON. MEANWHILE...UPSLOPE SNOW SHOWERS WILL DIMINISH TODAY WITH WARM ADVECTION AHEAD OF THE NEXT PAIR OF SHORT WAVES. GRADIENT WILL CONTINUE TO SUPPORT GUSTY WINDS...WITH WIND CHILLS THIS MORNING REMAINING IN THE NEGATIVE 5 TO 10 DEGREE RANGE WHERE THE ADVISORY REMAINS IN EFFECT. DESPITE CONTINUED COLD ADVECTION...TEMPERATURES SHOULD SURPASS 30F (WITH ONLY A SLOW RISE IN THE HIGHER TERRAIN). WIND CHILLS MAY DROP TO SIMILAR LEVELS OVERNIGHT IN THE MOUNTAINS WITH GUSTY WINDS REMAINING ABOVE 2500 FT. DECOUPLING IN THE LOWER TERRAIN WILL ALLOW TEMPERATURES TO DIP THROUGH THE TEENS. ANY REMAINING MID AND UPPER LEVEL MOISTURE ASSOCIATED WITH THE JET AXIS SHOULD BE SHUNTED TO THE SOUTHEAST OVERNIGHT...HOWEVER THE ARRIVAL OF A PAIR OF SHORTWAVES MAY PRODUCE ANOTHER AREA OF MID LEVEL MOISTURE FROM THE WEST. UPSLOPE SNOW SHOWERS ARE EXPECTED TO REDEVELOP AND INTENSIFY DURING THE OVERNIGHT HOURS AS THE SHORT WAVES PASS OVERHEAD. && .LONG TERM... UPSLOPE SNOW SHOWERS WILL COME TO AN END FRIDAY MORNING ALONG AND WEST OF THE ALLEGHENY FRONT. HIGH PRESSURE MOVES ACROSS THE SOUTHEAST CONUS FRIDAY AND FRIDAY NIGHT...ALLOWING COLD NORTHWEST WINDS ON FRIDAY TO SWING AROUND TO THE SOUTHWEST BY SATURDAY. THE NEXT WEATHER MAKER WILL MOVE THROUGH THE OHIO VALLEY ON SATURDAY...AND ACROSS THE MID ATLANTIC SATURDAY NIGHT INTO EARLY SUNDAY. THIS WEAK CLIPPER TYPE SYSTEM WILL BRING A CHANCE OF SNOW SHOWERS. IN THE WAKE OF THE CLIPPER...UPSLOPE SNOW SHOWERS WILL OCCUR OVER THE HIGHLANDS THROUGH THE REST OF THE WEEKEND. ZONAL FLOW DEVELOPS EARLY NEXT WEEK...AND THE MODELS SHOW HEIGHTS AND THICKNESSES RISING TO LEVELS THAT WOULD FAVOR TEMPERATURES CLOSER TO CLIMATOLOGY. && .AVIATION... MID-UPPER LEVEL MOISTURE IS DEVELOPING ALONG THE UPPER LEVEL JET AXIS ACROSS ACROSS CENTRAL VIRGINIA...AND WILL AFFECT THE TERMINALS DURING THE MORNING. GRADIENT WILL SUPPORT WIND GUSTS AROUND 20KTS...ESPECIALLY AFTER DAYBREAK. && .MARINE... 00Z MET/MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS DECREASE FROM 20KTS THIS MORNING TO 15 KTS THIS AFTERNOON...AND 12KTS TONIGHT. PROXIMITY NAM/GFS BUFKIT FORECAST SOUNDINGS INDICATE 20-25KT WIND GUST POTENTIAL THROUGH TONIGHT. ICE COVERAGE ACROSS THE EXTREME NORTHERN BAY IS CLOSE TO 7-9 TENTHS. SMALL CRAFT ADVISORY WIND SPEEDS WILL CONTINUE ON FRIDAY...HOWEVER EXCEPT A QUICK REDUCTION IN WIND SPEEDS FRIDAY EVENING WITH DECOUPLING. && .TIDES... CURRENT TIDAL DEPARTURES ARE A FOOT TO A FOOT AND A HALF BELOW ASTRONOMICAL PREDICTIONS...DUE TO A RECENT BLOWOUT. THE LUNAR CYCLE IS WANING TO A NEW MOON (8 PERCENT FULL). THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND THE NOAA EXTRATROPICAL STORM SURGE MODEL MAINTAIN CURRENT TIDAL DEPARTURES THROUGH THIS AFTERNOON. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR MDZ003>007- 501-502. VA...WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ021-028. WV...WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR WVZ050>052- 054-055-501>504. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST FRIDAY FOR ANZ530>534. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ535>537. SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EST FRIDAY FOR ANZ535>537. && SHORT TERM/AVIATION/TIDES...ROGOWSKI LONG TERM...PELOQUIN MARINE...ROGOWSKI/PELOQUIN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1155 AM EST THU FEB 15 2007 .UPDATE... ISSUED A LES ADVY FOR SOUTHERN SCHOOLCRAFT AS INTENSE SNOW BAND OFF LK SUPERIOR IS REACHING AS FAR INLAND AS BLANEY PARK PER SPOTTER REPORTS...RADAR...SATELLITE LOOP. RADAR SHOWS THE PRIMARY BAND IS AFFECTING EASTERN ALGER AND NORTHERN SCHOOLCRAFT COUNTIES. HAD REPORT FM SCHOOLCRAFT SHERIFF EARLIER OF 10 INCHES OF SNOW SINCE 8 AM ALONG MID POINT OF M-28 ON SENEY STRETCH. PRETTY IMPRESSIVE. SPOTTERS IN LUCE COUNTY REPORT REPORT SIGNIFICANTLY LESS ACCUMS...ON ORDER OF AN 1-3 INCHES IN LAST 12 HRS. ISOLD BAND OF HEAVY LES SHOULD TRANSLATE EWD INTO WEST LUCE COUNTY BY LATE AFTN AS WINDS IN BLYR ARE BACKING MORE WESTERLY. ELSEWHERE ACROSS THE CWA...IT IS PRETTY QUIET. STILL SEEING SOME MOISTURE STARVED...ICE INHIBITED ...LES OVR KEWEENAW. NOT MUCH IN WAY OF ACCUMS THERE. HOWEVER...VSBY AND SPOTTER REPORT AT KCMX SHOWING VSBY UNDER A MILE DUE TO MAINLY GUSTY WINDS/BLSN. ARE ALSO SEEING AN INCREASE IN WINDS HERE AT NWS MQT WHICH IS ALSO PRODUCING BLSN. STDM4 HAD A COUPLE GUSTS EARLIER TO NEAR GALE. OVERALL...STRONGER WINDS WILL BE THIS AFTN BUT DID ADD BLSN IN FAVORED AREAS OF KEWEENAW. SNOW SHOWERS MAY TRY TO INCREASE THERE BRIEFLY THIS AFTN AS WINDS BECOME MORE WEST...BUT EXTENSIVE ICE COVERAGE OVR WEST LK SUPERIOR WILL CUT DOWN THE EFFECTIVE OVER WATER FETCH EVEN WITH MORE FAVORABLE DIRECTION. TEMPS LOOKED FINE...MADE NO CHANGES THERE. && .DISCUSSION (330 AM EST)... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF WITH CLOSED H5 CENTER JUST NE OF LK SUP SANDWICHED BTWN RDG OFF SE CAN AND ANOTHER ONE FM THE ERN PAC EXTENDING NE INTO SW CAN. SLOWLY VEERING 330-350 DEGREE WIND BTWN ARCTIC HI PRES IN THE PLAINS AND LO PRES TO THE E AS SHOWN BY MQT VWP ADVECTING CORE OF COLDEST AIRMASS OVER NRN ONTARIO INTO THE UPR GRT LKS...H85 TEMPS AS LO AS -22C OVER ERN LK SUP PER RUC ANALYSIS. NMRS WIND PARALLEL LES BANDS NOTED ON MQT 88D TO THE E TENDING TO DRIFT SLOWLY W WITH TIME RIGHT NOW AS PATCH OF MID/HI CLD...SHOWN ON IR STLT IMAGERY AND ASSOCIATED WITH SHRTWV OVER ONTARIO ROTATING S ON WRN FLANK OF CLOSED H5 LO...IS DRIFTING ACRS THE FA. SUSPECT SLOWLY SHIFTING WINDS ACCOMPANYING THIS SHRTWV RESPONSIBLE FOR DRIFTING LES BANDS ATTM. 00Z TAMDAR SDNG FM SAW SHOWS HIER RH THRU H7 EXTENDING ABV INVRN ARND H85 ASSOCIATED WITH THIS SHRTWV...AND 00Z INL RAOB/TAMDAR SDNG FM DLH LOOKS SIMILAR. BUT 00Z YPL SDNG ON THE ACYC SIDE OF THIS REINFORCING SHRTWV SHOWS A DRIER MID LVL PROFILE ABOVE A SHARPER/LOWER INVRN ARND H880. SUB INVRN LYR IS ALSO DRIER WITH SFC DWPTS ARND -15F UPSTREAM OF LK SUP. MAIN FCST CONCERNS THIS PACKAGE REVOLVE ARND LES TRENDS/AMTS/ HEADLINES. FOR TDAY...GFS/NAM/CNDN MODELS SHOW SHRTWV ROTATING ARND CLOSED LO MOVING INTO LWR MI BY 00Z FRI. SOME DPVA/H85-5 QVECTOR CNVGC/MID LVL MSTR ASSOCIATED WITH THIS SYS FCST TO LINGER THRU THE MRNG BEFORE GIVING WAY TO DNVA/H85-5 QVECTOR DVGC/MID LVL DRYING IN THE AFTN. 00Z NAM APPEARS TO HAVE BEST HANDLE ON LATEST VEERING WIND TRENDS/ FOCUSED H95 CNVGC/DRIFTING LES BANDS...SO FOLLOWING ITS GUIDANCE MOST CLOSELY FOR FCST TDAY. MODEL SHOWS 340-350 DEGREE WIND WITH FOCUSED LLVL CNVGC OVER CNTRL ALGER/NW SCHOOLCRAFT COUNTIES EARLY THIS MRNG GRDLY BACKING TO 310-320 DEGREES BY 00Z FRI WITH MORE FOCUSED LLVL CNVGC SHIFTING INTO ERN ALGER/NE SCHOOLCRAFT/LUCE COUNTIES IN THE WAKE OF SHRTWV PASSAGE. ALTHOUGH SHIFTING WINDS THIS AFTN WL TEND TO LIMIT RESIDENCE TIME OF BANDS...WL MAINTAIN GOING WRNG FOR ALGER/NRN SCHOOLCRAFT THRU THE DAY. OPTED TO ISSUE LES ADVY FOR LUCE COUNTY BEGINNING MID MRNG AND EXTENDING THRU THE DAY WITH ARRIVAL OF BETTER CNVGC IN THE AFTN. ALTHOUGH SOME MID LVL DRYING WL BE ONGOING THEN...NAM FCST SDNG FOR ERY SHOWS ONLY WEAK INVRN DVLPG ARND 7K FT BY 00Z WITH MOIST PROFILE UP TO THAT LVL. GFS IS A LITTLE FASTER AT SHARPENING INVRN ARND H85...BUT FCST SDNG SHOWS DEEPER MSTR LINGERING THRU H75. LES CHART FOR THESE CONDITIONS WITH TEMPS FVRBL FOR DENDRITIC SN GROWTH AND LK-H85 DELTA T STILL ARND 20C WOULD YIELD UP TO 5"/12 HRS. SHORTER FETCH OVER THE W...EXACERBATED BY RECENT ICE BUILDUP...AS WELL AS SHIFTING WINDS/FASTER ARRIVAL OF MORE ACYC FLOW THIS AFTN WL LIMIT SN ACCUMULATIONS THERE TO THE SUB ADVY RANGE EVEN THOUGH THERE IS SOME FOCUSED CNVGC OVER ONTONAGON COUNTY THIS MRNG IN THE PRESENCE OF DPVA/SOME MID LVL MSTR. A SPOTTER REPORT NEAR ONTONAGON INDICATED ONLY 0.5 INCH FELL THERE THRU 9 PM YDAY EVNG. EXPECT NOTHING MORE THAN -SHSN/FLURRIES OVER THE INLAND CWA AWAY FM LK SUP LLVL MOISTENING. GFS/NAM MOS MAX TEMPS ARE VERY SIMILAR AND APPEAR RSNBL BASED ON MIXING TO INVRN BASE ON GFS FCST SDNGS. AS SHRTWV RDG/SFC RDG AXIS MOVES IN TNGT...EXPECT LINGERING LES TO END LATE OVER THE FAR E WITH CRASHING INVRN HGT BLO 3K FT/ARRIVAL OF MUCH DRIER AIR. LES WL LINGER LONGEST NEAR THE LK SUP SHORELINE E OF GRAND MARAIS. WL MAINTAIN 05Z END FOR WRNGS FOR ALGER/NRN SCHOOLCRAFT BUT KEEP ADVY FOR LUCE COUNTY GOING UNTIL 10Z. OTRW... SKIES WL CLR IN THE EVNG TO THE W BEFORE GFS/NAM INDICATE AN INCRS IN UPR LVL MSTR/HI CLD LATE WITH ISENTROPIC LIFT ON THE 290-300K SFC. ALTHOUGH THE LOWER TROP WL BE QUITE DRY...THE INFLUX OF THIS PACIFIC MSTR ALF AS WELL AS A TIGHTENING PRES GRADIENT/WLY FLOW TO THE N OF THE ARCTIC HI CENTER TRACKING WELL TO THE S WL LIMIT THE DIURNAL DROP IN TEMP. EVEN SO...PREFER THE LOWER NAM/NGM MOS GUIDANCE FOR LO TEMPS AS THERE MAY BE A WINDOW IN THE EVNG FOR TEMPS TO FALL QUICKLY BEFORE THE ARRIVAL OF THE HI CLD/HIER WINDS. NEXT CLIPPER SHRTWV FCST TO DROP SE THRU THE MIDWEST ON FRI...WELL S OF THE FA. HOWEVER...A WEAKER SHRTWV/SFC TROF PROGGED TO MOVE ACRS THE UPR GRT LKS TO THE N OF THE STRONGER FEATURE TO THE S. SOME MODELS GENERATE LGT PCPN (GENERALLY OVER THE W AND N) WHILE OTHERS ARE COMPLETELY DRY. CONSIDERING THE DRY ANTECEDENT AIRMASS IN THE LLVLS...WEAK ISENTROPIC ASCENT...MINIMAL MOS POPS (UNDER 20)...TRACK OF DEEPER LO TO THE S...AND LACK OF JET DYNAMICS/UPR DVGC...OPTED TO MAINTAIN ONLY LO CHC POPS OVER THE W/LK SUP AS IN GOING FCST WITH JUST SOME WEAK DPVA/H85-5 QVECTOR CNVGC AT TIMES DURING THE DAY. PREFER TO TEND TOWARD THE LOWER GFS MOS TEMPS PER MINIMAL ISENTROPIC LIFT AND STABLE LOOK TO FCST SDNGS. EXPECT LES TO DVLP LATER ON FRI NGT/SAT IN THE WAKE OF THIS NRN BRANCH SHRTWV/SFC TROF PASSAGE. GOING CHC -SN FRI NGT COINCIDENT WITH THE PASSAGE OF THIS FEATURE LOOKS ON TRACK AS DOES CHC -SHSN ON SAT IN THE COLD NW FLOW IN THE WAKE OF THE TROF. WL MAINTAIN HIEST POPS IN AREAS FVRD BY FCST NNW FLOW. EXPECT MODERATE LES AMTS IN THE FVRD AREAS...NOT ENUF FOR A HEADLINE ATTM. COORDINATED WITH APX/GRB. && .MQT WATCHES/WARNINGS/ADVISORIES... HEAVY FREEZING SPRAY WARNING FOR LAKE SUPERIOR. LAKE EFFECT SNOW ADVISORY 14Z TDAY THRU 10Z FRI MIZ007. LAKE EFFECT SNOW WARNING THRU 05Z FRI MIZ006-085. LAKE EFFECT SNOW ADVISORY THROUGH 00Z FRI MIZ014. && $$ UPDATE...JLA PREV DISCUSSION...KC
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1054 AM EST THU FEB 15 2007 .UPDATE...DEEP LAYER NORTH/NORTHWEST FLOW IN PLACE ACROSS THE WESTERN GREAT LAKES THIS MORNING...ON THE BACKSIDE OF STORM SYSTEM WHICH IMPACTED THE NORTHEAST ON WEDNESDAY. NORTHWEST FLOW LAKE SNOW BANDS COMING IN OFF LAKE MICHIGAN AFFECTING AREAS WEST OF I-75...LES BANDS OFF LAKE SUPERIOR STILL WEST OF CHIPPEWA COUNTY BUT IMPACTING WESTERN PORTIONS OF MACKINAC COUNTY. SOME DISORGANIZED CONVECTIVE ELEMENTS DRIFTING INTO WHITEFISH BAY... PROBABLY ASSOCIATED WITH LAND BREEZE CONVERGENCE OR SOME RESIDUAL EFFECTS OF LAND BREEZE GIVEN SOUTHWEST WIND AT ERY AND SOUTH/ SOUTHEAST WIND AT WHITEFISH POINT AND POINT IROQUOIS IMPLYING A MESOLOW OR SMALL SCALE TROUGH IN THAT VICINITY. SNOW BANDS ON NORTHERN LAKE HURON JUST CLIPPING AREAS AROUND PRESQUE ISLE. SOME COLDER CLOUDS TOPS EAST OF LAKE SUPERIOR GENERATING SOME LIGHT SNOW/FLURRIES ASSOCIATED WITH WARM ADVECTION/ISENTROPIC ASCENT AND VORTICITY LOBE EXTENDING NORTH/SOUTH ACROSS EASTERN ONTARIO. SOME OF THIS CLOUD COVER AND LIGHT SNOW GRAZING THE EASTERN END OF THE UPPER PENINSULA. 12Z APX SOUNDING PLACED INVERSION HEIGHT AROUND 800MB...850MB TEMPERATURE A BALMY -22C...LOW LEVEL FLOW HAS BECOME PREDOMINANTLY NORTHWEST (AROUND 310 DEGREES THROUGH 6K FEET PER KAPX VWP). AIRCRAFT SOUNDING OUT OF MQT SUGGESTS INVERSION HEIGHTS OFF LAKE SUPERIOR CLOSER TO 850MB. FOCUS FOR THE AFTERNOON WILL BE ON ONGOING LAKE EFFECT. ON LAKE SUPERIOR...APPEARS FLOW HAS SETTLED INTO THE 310-320 DEGREE RANGE WITH LITTLE CHANGE ANTICIPATED THROUGH THE AFTERNOON IN MEAN WIND DIRECTION OR INVERSION HEIGHT. SO POTENTIAL FOR SEVERAL INCHES OF SNOW THROUGH THE AFTERNOON ACROSS WESTERN CHIPPEWA COUNTY THOUGH BETTER SNOW BANDS ANOTHER HOUR OR TWO OFF. ALTHOUGH HASN`T SNOWED MUCH THUS FAR SINCE DAYBREAK...WILL LET THE ADVISORY RIDE AS THERE WILL PROBABLY BE SOME LOCALLY INTENSE SQUALLS THIS AFTERNOON. ON LAKE MICHIGAN...WINDS WILL BE A BIT MORE SHIFTY...ALREADY STARTING TO BACK TOWARD 290 OUT OVER LAKE MICHIGAN PER VISIBLE IMAGERY TRENDS. NO BIG CHANGES IN OVERALL LES PARAMETERS...850MB TEMPERATURES MODERATE A COUPLE DEGREES TODAY...BUT BACKING WINDS REDUCE EFFECTIVE FETCH OFF LAKE SUPERIOR...LONGEST EFFECTIVE FETCH WILL BE ACROSS FAR NORTHERN LAKE MICHIGAN WHERE THE ICE COVER IS GREATEST. THINK FOR THE AFTERNOON HOURS A GENERAL 1-3 INCHES POSSIBLE ACROSS FAVORED 290 FLOW AREAS...WILL KEEP THE CURRENT ADVISORY UP FOR ALL COUNTIES EXCEPT OTSEGO/CRAWFORD WHERE IT WAS SUNNY MUCH OF THE MORNING AND FINALLY STARTING TO SEE SOME LIGHT SNOWFALL. ANTICIPATE CLOUD COVER AND FLURRIES OR LIGHT SNOW SHOWERS TO SPREAD INLAND TODAY WITH THE DIURNAL HEATING CYCLE. SO MUCH OF NORTHEAST LOWER EXPECTED TO CLOUD UP AS THE AFTERNOON WEARS ON. JPB && .PREV DISCUSSION... /ISSUED 340 AM EST THU FEB 15 2007/ DEEP 500 MB LOW REMAINS CENTERED OVER SE ONTARIO EARLY THIS MORNING...WITH A BROAD SURFACE TROUGH EXTENDING FROM THE GREAT LAKES INTO NEW ENGLAND. LAKE EFFECT SNOW SHOWERS CONTINUE TO DEVELOP ACROSS LAKES SUPERIOR...MICHIGAN AND HURON UNDER THE DIRECTION OF NW FLOW. LOW LEVEL FLOW HAS TEMPORARILY SHIFTED NORTH ACROSS ERN LAKE SUPERIOR AND ERN UPPER MICHIGAN (ACTUALLY MORE N/NE FOR FAR ERN UPR MICHIGAN) IN RESPONSE TO A SHORT WAVE DIVING SOUTHWARD THRU CENTRAL UPPER MICHIGAN....HOLDING ALL SNOW SHOWER ACTIVITY WELL WEST OF I 75 ATTM. LOW LEVEL FLOW REMAINS FROM THE NW ACROSS NRN LAKE MICHIGAN AND NRN LAKE HURON...DIRECTING THE MOST PERSISTENT AND HIGHEST INTENSITY SNOW SHOWERS INTO THE TYPICAL SNOWBELT REGIONS OF NW/N CENTRAL LOWER MICHIGAN...WITH ANOTHER BAND WAVING ALONG THE LAKE HURON SHORELINE OF PRESQUE ISLE COUNTY. POTENTIAL FOR ADDITIONAL SNOW ACCUMULATION WITHIN THE ABOVE OUTLINED AREAS WILL REMAIN THE PRIMARY FORECAST ISSUE FOR THE NEXT 24 HOURS. RAPID WARMING AND A TEMPORARY BREAK IN SNOWFALL IS EXPECTED FOR FRIDAY BEFORE OUR NEXT CHANCE OF SNOW ARRIVES FRIDAY NIGHT AND OVER THE WEEKEND. TODAY AND TONIGHT...SHORT WAVE WILL SLOWLY DROP THRU LOWER MICHIGAN TODAY AND THIS EVENING. DELTA T`S WILL REMAIN AROUND 20 DEGREES THRU THIS EVENING AS 900-700 MB RH HOLDS AROUND 85 TO 90 PCT. INVERSION HEIGHTS WILL STAY AROUND 7 KFT THRU THIS EVENING AS WELL...WITH LITTLE CHANGE IN OVERALL LOW LEVEL NW WIND TRAJECTORIES. ONCE SHORT WAVE DROPS SOUTH INTO WISCONSIN AND LOWER MICHIGAN...LOW LEVEL WINDS SHOULD SHIFT BACK TO THE NW ACROSS ERN LAKE SUPERIOR AND ERN UPR MICHIGAN...REDIRECTING LAKE BANDS FURTHER EAST INTO CHIPPEWA COUNTY. SNOWBELT REGIONS OF NW/N CENTRAL LOWER MICHIGAN WILL CONTINUE TO RECEIVE THE MOST PERSISTENT AND HEAVIEST SNOWFALL THRU THIS EVENING. MINOR SHIFTS (UP TO 20 DEGREES) IN THE WIND THROUGHOUT THE DAY WILL ALLOW SNOW SHOWERS TO WAVE BACK AND FORTH ACROSS THIS SNOWBELT REGION... RESULTING IN A WIDER AREA OF SNOWFALL AND SLIGHTLY LESSER AMOUNTS IN ANY GIVEN LOCATION. WILL NEED TO SHIFT THE ADVISORY COUNTIES FURTHER INTO NW FLOW AREAS (I.E. CHARLEVOIX...OTSEGO AND CRAWFORD COUNTIES)...AND WILL DELETE BOTH BENZIE AND MANISTEE FROM THE ADVISORY BASED ON LATEST TRENDS AND THE EXPECTATION THAT LOW LEVEL FLOW WILL REMAIN OUT OF THE NW. IN COORDINATION WITH MQT... WILL ISSUE A LAKE EFFECT SNOW ADVISORY FOR ERN UPR MICHIGAN AS WELL. EXPECT 3-4 INCHES OF NEW SNOW FOR THE ADVISORY AREAS TODAY. SNOWFALL WILL CONTINUE INTO TONIGHT...BUT WILL BEGIN TO DIMINISH OVERNIGHT AS 850 MB TEMPS WARM TO AROUND -11C...900-700 MB RH DECREASES TO AROUND 30 PCT AND INVERSION HEIGHTS DROP TO BELOW 3 KFT BY 12Z SATURDAY. FRIDAY AND FRIDAY NIGHT...A FEW LIGHT SNOW SHOWERS MAY LINGER INTO FRIDAY MORNING AS DELTA T`S OF AROUND 10-11 C LINGER INTO EARLY FRIDAY. LOW LEVEL FLOW WILL BECOME WEST DURING THE DAY AND THEN SW AT NIGHT AS THE SURFACE RIDGE AXIS MOVES OVERHEAD DURING THE DAY AND THEN SHIFTS EAST OF THE REGION FRIDAY NIGHT. FRIDAY AFTERNOON SHOULD BE DRY...PARTLY SUNNY AND WARMER WITH HIGH TEMPS WARMING BACK INTO THE MID 20S. OUR NEXT CHANCE OF SNOW WILL ARRIVE FRIDAY NIGHT (ESPECIALLY OVERNIGHT) AS THE NEXT LOW PRESSURE SYSTEM MOVES INTO THE WRN GREAT LAKES REGION. SUFFICIENT LOW/MID LEVEL COOLING WILL OCCUR FRIDAY NIGHT TO BOTH STEEPEN LAPSE RATES AND TO ONCE AGAIN INVOLVE THE LAKES IN THE GENERATION OF SNOWFALL. WILL MAKE SOME SLIGHT INCREASES TO POPS ACROSS WRN SECTIONS OF THE CWA FOR FRIDAY NIGHT. LOW TEMPS FRIDAY NIGHT WILL DROP BACK INTO THE SINGLE DIGITS AND LOWER TEENS. SATURDAY AND SATURDAY NIGHT...WEAK SHORTWAVE AND ASSOCIATED COLD FRONT CROSS THE CWA DURING THE MORNING HOURS...WITH LOW LEVEL WINDS SHIFTING TO THE NW IN ITS WAKE. MARGINAL DELTA T/S TO START OUT THE DAY INCREASE TO THE NEGATIVE MID TEENS BY EVENING...AND NEGATIVE UPPER TEENS TO LOW 20S OVERNIGHT AS AN ARCTIC STREAM SHORTWAVE DROPS SOUTH AND REINFORCES THE COLD AIR OVER THE GREAT LAKES. INVERSION HEIGHTS GET A BOOST FROM THIS SECONDARY SHORTWAVE AND 900-700MB RH GREATER THAN 65 PCT WILL BE PRESENT THE ENTIRE PERIOD. HAVE SEEN ENOUGH EVIDENCE OVER THE LAST FEW MODEL RUNS TO BUMP UP WORDING TO LIKELY ACROSS THE NW LAKE EFFECT SNOW BELTS FROM SATURDAY AFTERNOON THROUGH SATURDAY NIGHT. SUNDAY AND SUNDAY NIGHT...ONGOING NW FLOW LAKE EFFECT SNOW WILL BE GRADUALLY DIMINISHING WITH INCREASING ANTICYCLONIC FLOW AND SUBSIDENCE...AND LOWERING INVERSION HEIGHTS. WILL MAINTAIN ONGOING CHANCE POPS ON SUNDAY ACROSS THE NW FLOW REGIMES. 850MB TEMPS REMAIN IN THE NEGATIVE MIDDLE TO UPPER TEENS TO START OUT THE NIGHT BUT QUICKLY WARM TO THE NEGATIVE LOWER TO MIDDLE TEENS BY MORNING AS THE SURFACE RIDGE AXIS PASSES ACROSS THE STATE OVERNIGHT. MODELS DEPICT A WARM FRONT ARRIVING BY MORNING AND FUTURE SHIFTS MAY WANT TO CONSIDER ADDING POPS IF THIS FEATURE PERSISTS. MONDAY INTO MONDAY NIGHT...850MB TEMPS WILL CONTINUE TO WARM DUE TO SOUTHWEST WINDS AHEAD OF A BROAD AREA OF LOW PRESSURE OVER THE GREAT PLAINS. TIMING OF FEATURES A LITTLE SKETCHY AT THIS POINT AS THE MODELS CONTINUE TO HAVE A DIFFICULT TIME DEPICTING THE UPCOMING PATTERN CHANGE. NONETHELESS..THE WARMEST AIR IN QUITE SOME TIME DUE TO ARRIVE BY EARLY NEXT WEEK WITH 850MB TEMPS WARMING INTO THE NEGATIVE SINGLE DIGITS. VERY FEW CHANGES MADE DURING THIS PERIOD WITH ONGOING UNCERTAINTY. MPC && .APX WATCHES/WARNINGS/ADVISORIES...LAKE EFFECT SNOW ADVISORY... THIS AFTERNOON...MIZ008-019>021-026-027. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
330 AM EST THU FEB 15 2007 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF WITH CLOSED H5 CENTER JUST NE OF LK SUP SANDWICHED BTWN RDG OFF SE CAN AND ANOTHER ONE FM THE ERN PAC EXTENDING NE INTO SW CAN. SLOWLY VEERING 330-350 DEGREE WIND BTWN ARCTIC HI PRES IN THE PLAINS AND LO PRES TO THE E AS SHOWN BY MQT VWP ADVECTING CORE OF COLDEST AIRMASS OVER NRN ONTARIO INTO THE UPR GRT LKS...H85 TEMPS AS LO AS -22C OVER ERN LK SUP PER RUC ANALYSIS. NMRS WIND PARALLEL LES BANDS NOTED ON MQT 88D TO THE E TENDING TO DRIFT SLOWLY W WITH TIME RIGHT NOW AS PATCH OF MID/HI CLD...SHOWN ON IR STLT IMAGERY AND ASSOCIATED WITH SHRTWV OVER ONTARIO ROTATING S ON WRN FLANK OF CLOSED H5 LO...IS DRIFTING ACRS THE FA. SUSPECT SLOWLY SHIFTING WINDS ACCOMPANYING THIS SHRTWV RESPONSIBLE FOR DRIFTING LES BANDS ATTM. 00Z TAMDAR SDNG FM SAW SHOWS HIER RH THRU H7 EXTENDING ABV INVRN ARND H85 ASSOCIATED WITH THIS SHRTWV...AND 00Z INL RAOB/TAMDAR SDNG FM DLH LOOKS SIMILAR. BUT 00Z YPL SDNG ON THE ACYC SIDE OF THIS REINFORCING SHRTWV SHOWS A DRIER MID LVL PROFILE ABOVE A SHARPER/LOWER INVRN ARND H880. SUB INVRN LYR IS ALSO DRIER WITH SFC DWPTS ARND -15F UPSTREAM OF LK SUP. MAIN FCST CONCERNS THIS PACKAGE REVOLVE ARND LES TRENDS/AMTS/ HEADLINES. FOR TDAY...GFS/NAM/CNDN MODELS SHOW SHRTWV ROTATING ARND CLOSED LO MOVING INTO LWR MI BY 00Z FRI. SOME DPVA/H85-5 QVECTOR CNVGC/MID LVL MSTR ASSOCIATED WITH THIS SYS FCST TO LINGER THRU THE MRNG BEFORE GIVING WAY TO DNVA/H85-5 QVECTOR DVGC/MID LVL DRYING IN THE AFTN. 00Z NAM APPEARS TO HAVE BEST HANDLE ON LATEST VEERING WIND TRENDS/ FOCUSED H95 CNVGC/DRIFTING LES BANDS...SO FOLLOWING ITS GUIDANCE MOST CLOSELY FOR FCST TDAY. MODEL SHOWS 340-350 DEGREE WIND WITH FOCUSED LLVL CNVGC OVER CNTRL ALGER/NW SCHOOLCRAFT COUNTIES EARLY THIS MRNG GRDLY BACKING TO 310-320 DEGREES BY 00Z FRI WITH MORE FOCUSED LLVL CNVGC SHIFTING INTO ERN ALGER/NE SCHOOLCRAFT/LUCE COUNTIES IN THE WAKE OF SHRTWV PASSAGE. ALTHOUGH SHIFTING WINDS THIS AFTN WL TEND TO LIMIT RESIDENCE TIME OF BANDS...WL MAINTAIN GOING WRNG FOR ALGER/NRN SCHOOLCRAFT THRU THE DAY. OPTED TO ISSUE LES ADVY FOR LUCE COUNTY BEGINNING MID MRNG AND EXTENDING THRU THE DAY WITH ARRIVAL OF BETTER CNVGC IN THE AFTN. ALTHOUGH SOME MID LVL DRYING WL BE ONGOING THEN...NAM FCST SDNG FOR ERY SHOWS ONLY WEAK INVRN DVLPG ARND 7K FT BY 00Z WITH MOIST PROFILE UP TO THAT LVL. GFS IS A LITTLE FASTER AT SHARPENING INVRN ARND H85...BUT FCST SDNG SHOWS DEEPER MSTR LINGERING THRU H75. LES CHART FOR THESE CONDITIONS WITH TEMPS FVRBL FOR DENDRITIC SN GROWTH AND LK-H85 DELTA T STILL ARND 20C WOULD YIELD UP TO 5"/12 HRS. SHORTER FETCH OVER THE W...EXACERBATED BY RECENT ICE BUILDUP...AS WELL AS SHIFTING WINDS/FASTER ARRIVAL OF MORE ACYC FLOW THIS AFTN WL LIMIT SN ACCUMULATIONS THERE TO THE SUB ADVY RANGE EVEN THOUGH THERE IS SOME FOCUSED CNVGC OVER ONTONAGON COUNTY THIS MRNG IN THE PRESENCE OF DPVA/SOME MID LVL MSTR. A SPOTTER REPORT NEAR ONTONAGON INDICATED ONLY 0.5 INCH FELL THERE THRU 9 PM YDAY EVNG. EXPECT NOTHING MORE THAN -SHSN/FLURRIES OVER THE INLAND CWA AWAY FM LK SUP LLVL MOISTENING. GFS/NAM MOS MAX TEMPS ARE VERY SIMILAR AND APPEAR RSNBL BASED ON MIXING TO INVRN BASE ON GFS FCST SDNGS. AS SHRTWV RDG/SFC RDG AXIS MOVES IN TNGT...EXPECT LINGERING LES TO END LATE OVER THE FAR E WITH CRASHING INVRN HGT BLO 3K FT/ARRIVAL OF MUCH DRIER AIR. LES WL LINGER LONGEST NEAR THE LK SUP SHORELINE E OF GRAND MARAIS. WL MAINTAIN 05Z END FOR WRNGS FOR ALGER/NRN SCHOOLCRAFT BUT KEEP ADVY FOR LUCE COUNTY GOING UNTIL 10Z. OTRW... SKIES WL CLR IN THE EVNG TO THE W BEFORE GFS/NAM INDICATE AN INCRS IN UPR LVL MSTR/HI CLD LATE WITH ISENTROPIC LIFT ON THE 290-300K SFC. ALTHOUGH THE LOWER TROP WL BE QUITE DRY...THE INFLUX OF THIS PACIFIC MSTR ALF AS WELL AS A TIGHTENING PRES GRADIENT/WLY FLOW TO THE N OF THE ARCTIC HI CENTER TRACKING WELL TO THE S WL LIMIT THE DIURNAL DROP IN TEMP. EVEN SO...PREFER THE LOWER NAM/NGM MOS GUIDANCE FOR LO TEMPS AS THERE MAY BE A WINDOW IN THE EVNG FOR TEMPS TO FALL QUICKLY BEFORE THE ARRIVAL OF THE HI CLD/HIER WINDS. NEXT CLIPPER SHRTWV FCST TO DROP SE THRU THE MIDWEST ON FRI...WELL S OF THE FA. HOWEVER...A WEAKER SHRTWV/SFC TROF PROGGED TO MOVE ACRS THE UPR GRT LKS TO THE N OF THE STRONGER FEATURE TO THE S. SOME MODELS GENERATE LGT PCPN (GENERALLY OVER THE W AND N) WHILE OTHERS ARE COMPLETELY DRY. CONSIDERING THE DRY ANTECEDENT AIRMASS IN THE LLVLS...WEAK ISENTROPIC ASCENT...MINIMAL MOS POPS (UNDER 20)...TRACK OF DEEPER LO TO THE S...AND LACK OF JET DYNAMICS/UPR DVGC...OPTED TO MAINTAIN ONLY LO CHC POPS OVER THE W/LK SUP AS IN GOING FCST WITH JUST SOME WEAK DPVA/H85-5 QVECTOR CNVGC AT TIMES DURING THE DAY. PREFER TO TEND TOWARD THE LOWER GFS MOS TEMPS PER MINIMAL ISENTROPIC LIFT AND STABLE LOOK TO FCST SDNGS. EXPECT LES TO DVLP LATER ON FRI NGT/SAT IN THE WAKE OF THIS NRN BRANCH SHRTWV/SFC TROF PASSAGE. GOING CHC -SN FRI NGT COINCIDENT WITH THE PASSAGE OF THIS FEATURE LOOKS ON TRACK AS DOES CHC -SHSN ON SAT IN THE COLD NW FLOW IN THE WAKE OF THE TROF. WL MAINTAIN HIEST POPS IN AREAS FVRD BY FCST NNW FLOW. EXPECT MODERATE LES AMTS IN THE FVRD AREAS...NOT ENUF FOR A HEADLINE ATTM. COORDINATED WITH APX/GRB. && .MQT WATCHES/WARNINGS/ADVISORIES... HEAVY FREEZING SPRAY WARNING FOR LAKE SUPERIOR. LAKE EFFECT SNOW ADVISORY 14Z TDAY THRU 10Z FRI MIZ007. LAKE EFFECT SNOW WARNING THRU 05Z FRI MIZ006-085. && $$ KC
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1105 AM EST SAT FEB 17 2007 .MESO UPDATE... REGIONAL RADAR MOSAIC SHOWING A HEALTHY BATCH OF SNOW OVER THE LOWER OHIO VALLEY ASSOC WITH INCOMING CLIPPER SYSTEM...BEST COVERAGE AND HIGHEST INTENSITIES FROM ROUGHLY I-65 WEST INTO WRN KY/SRN IL/SW IN AS OF 1545Z. BANDS OF SNOW HAVE BEEN PRODUCING QUICK ACCUMS OVER WRN PARTS OF THE CWA...WITH VISIBILITIES DOWN TO BELOW ONE HALF MILE BASED ON SFC OBS AND WEBCAMS. CALLS TO SPOTTERS AND COOPERATIVE OBSERVERS INDICATE A WIDESPREAD 2" SNOWFALL THUS FAR ROUGHLY WEST OF A BWG-HARDINSBURG-ENGLISH LINE...WITH A RAPID DROP OFF TO THE EAST DUE TO EARLIER DRY LOW LEVEL AIRMASS. SEE LOCAL STORM REPORTS FOR SPECIFIC REPORTS. RADAR TRENDS INDICATE THAT MOST SUBSTANTIAL PRECIP WILL LIKELY AFFECT LOCATIONS ALONG AND SOUTH OF I-64 THROUGH THE AFTN HOURS... THOUGH IT WILL LIKELY BE MORE SHOWERY/BANDED IN NATURE. ONE INTERESTING FEATURE PRESSING EASTWARD THROUGH FAR WRN KY...THAT ON EARLIER RADAR IMAGES COULD BE CALLED A "SQUALL LINE OF SNOW"...JUST HAD THAT LOOK TO IT. THIS WILL AFFECT SRN PORTIONS OF THE CWA INTO EARLY AFTN. BASED ON FCST SOUNDINGS FROM 12Z RUC MOST OF THE PRECIP THIS AFTN SHOULD BE IN THE FORM OF SNOW. HOWEVER...EARLIER ACARS SOUNDINGS AT MEMPHIS SEEMED TO SUGGEST THAT RUC IS A TOUCH TOO COOL IN THE BOUNDARY LAYER. THEREFORE WILL CONTINUE MENTION THAT RAIN MAY MIX IN WITH SNOW AT TIMES THIS AFTN OVER SRN KY. REGARDING AMOUNTS...BASED ON CURRENT REPORTS AND UPSTREAM PRECIP... WILL INCREASE TOTAL SNOWFALL AMOUNTS INTO THE 2-3" RANGE FOR MOST OF THE CWA. DUE TO BANDED/SHOWERY NATURE TO PRECIP...AMOUNTS WILL LIKELY VARY A LOT OVER SHORT DISTANCES...AND THERE COULD BE LOCALLY HIGHER AMOUNTS. SNOW WILL ALSO COME DOWN HEAVY AT TIMES GIVEN SOME RADAR RETURNS APPROACHING 40DBZ...HANDLING THIS WITH SPECIAL WX STATEMENTS. TWO AREAS THAT MAY SEE LESS ARE THE FAR NORTHERN COUNTIES (NEAR MADISON) BASED SOLELY ON RADAR INDICATIONS OF A RELATIVE MIN IN PRECIP COVERAGE...AND ALONG THE KY/TN LINE WHERE A RA/SN MIX MAY OCCUR. WILL SIMPLY MENTION THESE POSSIBILITIES IN THE WSW...LEAVING THE ALIGNMENT/TIMES THE SAME AS THEY ARE NOW. I DID INCREASE THE WIND GUSTS TONIGHT INTO THE 20-25KT RANGE BASED ON UPSTREAM OBSERVATIONS OVER MO/IL. IT`S NOW SNOWING PRETTY GOOD HERE AT THE WFO WITH DECENT SIZED FLAKES. UPDATED FCST/HEADLINES SHOULD BE OUT BY 1130 AM EST. CS && .SHORT TERM (TODAY AND TONIGHT)... A WEAKENING SURFACE LOW ALONG THE IOWA/MISSOURI BORDER AT 06Z WILL SLIDE SOUTHEAST TODAY...OPENING UP INTO A TROF BY AFTERNOON AS IT PUSHES UP THE OHIO VALLEY AND THEN CROSSES THE APPALACHIANS THIS EVENING. TWO UPPER LEVEL SHORTWAVE TROFS THAT ARE READILY VISIBLE IN SATELLITE IMAGERY WILL BE PASSING OVERHEAD. THE FIRST IMPULSE WAS LOCATED NEAR PADUCAH AT 06Z. THE SECOND...SLIGHTLY STRONGER...WAVE WAS JUST NORTH OF KANSAS CITY. THE FIRST UPPER DISTURBANCE WILL BRING A BATCH OF SNOW ACROSS THE CWFA EARLY THIS MORNING. THE SNOW MAY BECOME MODERATE AT TIMES BUT IS MOVING QUICKLY AND ANYTHING MORE THAN LIGHT SNOW WOULD ONLY LAST FOR A BRIEF PERIOD OF TIME. ACCUMULATIONS WITH THIS FIRST AREA OF SNOW SHOULD BE AROUND AN INCH. WITH SURFACE TEMPERATURES QUITE COLD FROM THE RECENT CHILLY WEATHER THE SNOW SHOULD HAVE NO PROBLEM STICKING SO SOME SLICK ROADS MAY DEVELOP THIS MORNING. AFTER A BREAK IN THE SNOW LATE THIS MORNING AND EARLY THIS AFTERNOON...THE NEXT BATCH OF LIGHT SNOW WILL MOVE THROUGH THE REGION MID-AFTERNOON INTO EARLY EVENING. THIS NEXT BATCH OF SNOW WILL ALSO BE CAPABLE OF DROPPING AROUND AN INCH OF ACCUMULATION. MOS TEMPERATURES AT 06Z WERE ALMOST ALL RUNNING TOO COOL... ESPECIALLY OVER SOUTHERN KENTUCKY. LOOKING AT POSSIBLE AFTERNOON HIGHS...IT SEEMS SOUTHERN KENTUCKY SHOULD BE ABLE TO GET A FEW DEGREES ABOVE FREEZING. THEREFORE SOME RAIN MAY MIX IN WITH THE SNOW...LIMITING ACCUMULATIONS THERE. SNOW WILL GRADUALLY DEPART FROM WEST TO EAST THIS EVENING. WITH THE SNOW LINGERING A BIT LONGER IN THE BLUE GRASS (LEXINGTON) AREA TOTAL ACCUMULATIONS THERE WILL LIKELY BE THE HIGHEST IN CENTRAL KENTUCKY...AROUND 2 TO AS MUCH AS 2 AND A HALF INCHES. THESE AMOUNTS ARE IN GENERAL AGREEMENT WITH HPC THINKING WHICH INDICATES AMOUNTS OF 1 TO 2 INCHES TODAY. WINDS WILL SHIFT TO THE WEST THIS AFTERNOON AND NORTHWEST THIS EVENING AND WILL BECOME SOMEWHAT BREEZY...WITH A FEW GUSTS TO 20 OR 25 MPH POSSIBLE. AS TEMPERATURES DROP INTO THE TEENS THIS WILL CAUSE WIND CHILLS TO FALL INTO THE SINGLE DIGITS BY LATE TONIGHT. 13 .LONG TERM (SUNDAY-FRIDAY)... A LOW PRESSURE SYSTEM WILL BE MOVING WELL NORTHEAST OF THE AREA BY SUNDAY MORNING WITH ONLY LIGHT SNOW...MAINLY OVER THE EAST LINGERING BEHIND THE LOW. THUS MAIN CONCERNS IN THE LONGER TERM WILL BE ENDING OF PRECIPITATION...HOW COLD FOR SUNDAY NIGHT BEFORE A WARMING TREND SETS IN OVER THE AREA...AND THEN PRECIPITATION WITH THE NEXT SYSTEM AT MID WEEK. SUNDAY THROUGH MONDAY.... AS MENTIONED ABOVE...MOST OF THE SNOW WILL HAVE ENDED OVER THE AREA BY 12Z WITH ONLY LINGERING LIGHT SNOW OVER THE EAST AND NORTHEAST. THIS WILL DECREASE RAPIDLY DURING THE MORNING AS THE LOW CONTINUES TO MOVE AWAY AND HIGH PRESSURE BEGINS TO NUDGE INTO CENTRAL KENTUCKY. WITH LOWER CLOUDS PERSISTING CANNOT RULE OUT A FEW FLURRIES DEVELOPING BUT THESE SHOULD NOT BE SIGNIFICANT. CLOUDS WILL BEGIN TO DECREASE DURING THE DAY SUNDAY WITH SKIES BECOMING PARTLY CLOUDY TO MOSTLY CLEAR OVER THE ENTIRE REGION OVERNIGHT. COLDEST AIR WILL BE OVER CENTRAL KENTUCKY SUNDAY MORNING BUT WITH LIGHT WINDS AND MOSTLY CLEAR SKIES...THERE WILL BE GOOD RADIATIONAL COOLING SUNDAY NIGHT. TEMPERATURES WILL FALL RAPIDLY AFTER SUNSET... BUT AS THE SURFACE HIGH MOVES EAST...WINDS WILL BECOME SOUTHERLY AND INCREASE SLIGHTLY...SLOWING THE COOLING. HAVE RAISED MINS UP A FEW DEGREES FOR THIS REASON. UPPER FLOW BECOMES MORE ZONAL ON MONDAY AND THERE WILL BE PLENTY OF SUNSHINE BEFORE CLOUDS BEGIN TO INCREASE AHEAD OF NEXT SYSTEM MONDAY NIGHT. SOUTHERLY WINDS AROUND THE BACK SIDE OF THE HIGH MOVING OFF THE EAST COAST WILL BRING WARMER AIR INTO THE LOWER OHIO VALLEY WITH TEMPERATURES RISING INTO THE 40S. WILL GO SLIGHTLY BELOW MOS GUIDANCE. MONDAY NIGHT THROUGH FRIDAY... NEXT SYSTEM MOVES EAST AHEAD OF A TROUGH ADVANCING EAST FROM THE PACIFIC NORTHWEST. CLOUDS WILL INCREASE RAPIDLY MONDAY NIGHT AND THE CLOUDS ALONG WITH A GOOD SOUTHERLY FLOW WILL KEEP TEMPERATURES FROM FALLING MUCH BELOW THE MID 30S. EXPECT TO SEE A CHANCE OF RAIN AT LEAST OVER THE WEST HALF BY TUESDAY MORNING. RAIN WILL INCREASE OVER THE AREA DURING THE DAY TUESDAY WITH A BETTER CHANCE TUESDAY NIGHT INTO WEDNESDAY AS A COLD FRONT ASSOCIATED WITH THE TROUGH PUSHES ACROSS THE REGION. THE PRECIPITATION WILL END EARLY WEDNESDAY EVENING...BEFORE TEMPERATURES FALL ENOUGH TO TURN THE PRECIPITATION BACK TO SNOW. HIGH PRESSURE WILL KEEP DRY WEATHER OVER THE AREA FOR THE REST OF THE WEEK. SCHOLZ && .AVIATION (12Z TAFS)... A PAIR OF UPPER LEVEL WAVES WILL BRING LIGHT SNOW TO THE TAF SITES TODAY...TAPERING OFF EARLY THIS EVENING. CEILINGS AND VISIBILITIES WILL VARY QUITE A BIT TODAY...GOING BACK AND FORTH FROM VFR BETWEEN PATCHES OF SNOW TO BRIEFLY IFR WITHIN THE HEAVIER SNOW SHOWERS. FOR PREVAILING CONDITIONS KEPT THE TAFS GENERALLY MVFR. THE SNOW SHOULD TAPER OFF FROM WEST TO EAST THIS EVENING. WHILE BWG AND POSSIBLY SDF SHOULD LOSE THEIR LOW CEILING OVERNIGHT...MVFR CLOUDS WILL LIKELY HANG IN THROUGHOUT THE TAF PERIOD AT LEX. 13 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 3 AM EST /2 AM CST/ TO 6 PM EST /5 PM CST/ FOR KYZ023>034-038-045-053-061>063-070>074. SNOW ADVISORY FROM 6 AM EST /5 AM CST/ TO 11 PM EST /10 PM CST/ FOR KYZ035>037-039>043-046>049-054>057-064>067-075>078-081-082. IN...SNOW ADVISORY FROM 3 AM EST /2 AM CST/ TO 6 PM EST /5 PM CST/ FOR INZ076>079-083-084-089>092. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
850 AM EST SAT FEB 17 2007 .MESO UPDATE... CURRENT FCST IS ON TRACK. BANDS OF -SN TRANSLATING SE ACROSS THE LOWER OHIO VALLEY...WITH SOME VSBYS OVER WRN KY/SRN IL/SW IN COMING IN NEAR 1SM. GENERIC RULE OF THUMB IS THAT ANYTHING BELOW 3SM WILL ACCUMULATE. SNOW IS FINALLY GETTING INTO LEX AREA...BEING DELAYED DUE TO DRIER LOW LEVELS EAST OF I-65. YOU CAN ACTUALLY SEE THE TIGHT CIRCULATION IN RADAR DATA OVER SE MO ASSOC WITH 500MB VORTICITY MAXIMUM. 12Z RUC PICKS UP CURRENT PRECIP DISTRIBUTION WELL AND SWINGS PRECIP THROUGH THE CWA DURING THE BALANCE OF THE DAY INTO THE EARLY EVENING HOURS. RADAR TRENDS SUGGEST THAT SOME OF THESE BANDS COULD PIVOT AROUND SUCH THAT LOCALIZED ACCUMS ABOVE 2" ARE POSSIBLE...BUT EXACTLY WHERE THAT SETS UP IS UNCERTAIN AT THIS TIME. ONE CONCERN WITH DECENT SW FLOW AHEAD OF CLIPPER SYSTEM IS PRECIP TYPE. 12Z RUC FCST SOUNDINGS ARE A TOUCH TOO COOL WHEN COMPARED TO RECENT ACARS AT MEMPHIS. THEREFORE FEEL THAT CURRENT FCST OF A RASN MIX IN SRN KY THIS AFTN IS REASONABLE. FOR THE MOST PART PTYPE ELSEWHERE IS EXPECTED TO BE SNOW...BUT WILL BE WATCHED CAREFULLY WITH TEMPS NEARING 30F IN MANY LOCATIONS. NO UPDATES AT THIS TIME. CS && .SHORT TERM (TODAY AND TONIGHT)... A WEAKENING SURFACE LOW ALONG THE IOWA/MISSOURI BORDER AT 06Z WILL SLIDE SOUTHEAST TODAY...OPENING UP INTO A TROF BY AFTERNOON AS IT PUSHES UP THE OHIO VALLEY AND THEN CROSSES THE APPALACHIANS THIS EVENING. TWO UPPER LEVEL SHORTWAVE TROFS THAT ARE READILY VISIBLE IN SATELLITE IMAGERY WILL BE PASSING OVERHEAD. THE FIRST IMPULSE WAS LOCATED NEAR PADUCAH AT 06Z. THE SECOND...SLIGHTLY STRONGER...WAVE WAS JUST NORTH OF KANSAS CITY. THE FIRST UPPER DISTURBANCE WILL BRING A BATCH OF SNOW ACROSS THE CWFA EARLY THIS MORNING. THE SNOW MAY BECOME MODERATE AT TIMES BUT IS MOVING QUICKLY AND ANYTHING MORE THAN LIGHT SNOW WOULD ONLY LAST FOR A BRIEF PERIOD OF TIME. ACCUMULATIONS WITH THIS FIRST AREA OF SNOW SHOULD BE AROUND AN INCH. WITH SURFACE TEMPERATURES QUITE COLD FROM THE RECENT CHILLY WEATHER THE SNOW SHOULD HAVE NO PROBLEM STICKING SO SOME SLICK ROADS MAY DEVELOP THIS MORNING. AFTER A BREAK IN THE SNOW LATE THIS MORNING AND EARLY THIS AFTERNOON...THE NEXT BATCH OF LIGHT SNOW WILL MOVE THROUGH THE REGION MID-AFTERNOON INTO EARLY EVENING. THIS NEXT BATCH OF SNOW WILL ALSO BE CAPABLE OF DROPPING AROUND AN INCH OF ACCUMULATION. MOS TEMPERATURES AT 06Z WERE ALMOST ALL RUNNING TOO COOL... ESPECIALLY OVER SOUTHERN KENTUCKY. LOOKING AT POSSIBLE AFTERNOON HIGHS...IT SEEMS SOUTHERN KENTUCKY SHOULD BE ABLE TO GET A FEW DEGREES ABOVE FREEZING. THEREFORE SOME RAIN MAY MIX IN WITH THE SNOW...LIMITING ACCUMULATIONS THERE. SNOW WILL GRADUALLY DEPART FROM WEST TO EAST THIS EVENING. WITH THE SNOW LINGERING A BIT LONGER IN THE BLUE GRASS (LEXINGTON) AREA TOTAL ACCUMULATIONS THERE WILL LIKELY BE THE HIGHEST IN CENTRAL KENTUCKY...AROUND 2 TO AS MUCH AS 2 AND A HALF INCHES. THESE AMOUNTS ARE IN GENERAL AGREEMENT WITH HPC THINKING WHICH INDICATES AMOUNTS OF 1 TO 2 INCHES TODAY. WINDS WILL SHIFT TO THE WEST THIS AFTERNOON AND NORTHWEST THIS EVENING AND WILL BECOME SOMEWHAT BREEZY...WITH A FEW GUSTS TO 20 OR 25 MPH POSSIBLE. AS TEMPERATURES DROP INTO THE TEENS THIS WILL CAUSE WIND CHILLS TO FALL INTO THE SINGLE DIGITS BY LATE TONIGHT. 13 .LONG TERM (SUNDAY-FRIDAY)... A LOW PRESSURE SYSTEM WILL BE MOVING WELL NORTHEAST OF THE AREA BY SUNDAY MORNING WITH ONLY LIGHT SNOW...MAINLY OVER THE EAST LINGERING BEHIND THE LOW. THUS MAIN CONCERNS IN THE LONGER TERM WILL BE ENDING OF PRECIPITATION...HOW COLD FOR SUNDAY NIGHT BEFORE A WARMING TREND SETS IN OVER THE AREA...AND THEN PRECIPITATION WITH THE NEXT SYSTEM AT MID WEEK. SUNDAY THROUGH MONDAY.... AS MENTIONED ABOVE...MOST OF THE SNOW WILL HAVE ENDED OVER THE AREA BY 12Z WITH ONLY LINGERING LIGHT SNOW OVER THE EAST AND NORTHEAST. THIS WILL DECREASE RAPIDLY DURING THE MORNING AS THE LOW CONTINUES TO MOVE AWAY AND HIGH PRESSURE BEGINS TO NUDGE INTO CENTRAL KENTUCKY. WITH LOWER CLOUDS PERSISTING CANNOT RULE OUT A FEW FLURRIES DEVELOPING BUT THESE SHOULD NOT BE SIGNIFICANT. CLOUDS WILL BEGIN TO DECREASE DURING THE DAY SUNDAY WITH SKIES BECOMING PARTLY CLOUDY TO MOSTLY CLEAR OVER THE ENTIRE REGION OVERNIGHT. COLDEST AIR WILL BE OVER CENTRAL KENTUCKY SUNDAY MORNING BUT WITH LIGHT WINDS AND MOSTLY CLEAR SKIES...THERE WILL BE GOOD RADIATIONAL COOLING SUNDAY NIGHT. TEMPERATURES WILL FALL RAPIDLY AFTER SUNSET... BUT AS THE SURFACE HIGH MOVES EAST...WINDS WILL BECOME SOUTHERLY AND INCREASE SLIGHTLY...SLOWING THE COOLING. HAVE RAISED MINS UP A FEW DEGREES FOR THIS REASON. UPPER FLOW BECOMES MORE ZONAL ON MONDAY AND THERE WILL BE PLENTY OF SUNSHINE BEFORE CLOUDS BEGIN TO INCREASE AHEAD OF NEXT SYSTEM MONDAY NIGHT. SOUTHERLY WINDS AROUND THE BACK SIDE OF THE HIGH MOVING OFF THE EAST COAST WILL BRING WARMER AIR INTO THE LOWER OHIO VALLEY WITH TEMPERATURES RISING INTO THE 40S. WILL GO SLIGHTLY BELOW MOS GUIDANCE. MONDAY NIGHT THROUGH FRIDAY... NEXT SYSTEM MOVES EAST AHEAD OF A TROUGH ADVANCING EAST FROM THE PACIFIC NORTHWEST. CLOUDS WILL INCREASE RAPIDLY MONDAY NIGHT AND THE CLOUDS ALONG WITH A GOOD SOUTHERLY FLOW WILL KEEP TEMPERATURES FROM FALLING MUCH BELOW THE MID 30S. EXPECT TO SEE A CHANCE OF RAIN AT LEAST OVER THE WEST HALF BY TUESDAY MORNING. RAIN WILL INCREASE OVER THE AREA DURING THE DAY TUESDAY WITH A BETTER CHANCE TUESDAY NIGHT INTO WEDNESDAY AS A COLD FRONT ASSOCIATED WITH THE TROUGH PUSHES ACROSS THE REGION. THE PRECIPITATION WILL END EARLY WEDNESDAY EVENING...BEFORE TEMPERATURES FALL ENOUGH TO TURN THE PRECIPITATION BACK TO SNOW. HIGH PRESSURE WILL KEEP DRY WEATHER OVER THE AREA FOR THE REST OF THE WEEK. SCHOLZ && .AVIATION (12Z TAFS)... A PAIR OF UPPER LEVEL WAVES WILL BRING LIGHT SNOW TO THE TAF SITES TODAY...TAPERING OFF EARLY THIS EVENING. CEILINGS AND VISIBILITIES WILL VARY QUITE A BIT TODAY...GOING BACK AND FORTH FROM VFR BETWEEN PATCHES OF SNOW TO BRIEFLY IFR WITHIN THE HEAVIER SNOW SHOWERS. FOR PREVAILING CONDITIONS KEPT THE TAFS GENERALLY MVFR. THE SNOW SHOULD TAPER OFF FROM WEST TO EAST THIS EVENING. WHILE BWG AND POSSIBLY SDF SHOULD LOSE THEIR LOW CEILING OVERNIGHT...MVFR CLOUDS WILL LIKELY HANG IN THROUGHOUT THE TAF PERIOD AT LEX. 13 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 3 AM EST /2 AM CST/ TO 6 PM EST /5 PM CST/ FOR KYZ023>034-038-045-053-061>063-070>074. SNOW ADVISORY FROM 6 AM EST /5 AM CST/ TO 11 PM EST /10 PM CST/ FOR KYZ035>037-039>043-046>049-054>057-064>067-075>078-081-082. IN...SNOW ADVISORY FROM 3 AM EST /2 AM CST/ TO 6 PM EST /5 PM CST/ FOR INZ076>079-083-084-089>092. && $$
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PST SAT FEB 17 2007 .SYNOPSIS... UPPER LEVEL LOW PRESSURE APPROACHING FROM THE NORTHWEST WILL CAUSE CONSIDERABLE COOLING SUNDAY AND MONDAY WITH INCREASING CLOUDINESS. THIS LOW WILL BRING A CHANCE OF SHOWERS SUNDAY NIGHT THROUGH MONDAY NIGHT. FAIR AND BRIEFLY WARMER TUESDAY AND WEDNESDAY UNDER WEAK HIGH PRESSURE. ANOTHER LOW PRESSURE SYSTEM WILL BRING A CHANCE OF SHOWERS LATER NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES. .SHORT TERM (TONIGHT-TUE)... IT WAS VERY WARM TODAY WITH MOSTLY SUNNY SKIES EXCEPT FOR A FEW HIGH CLOUDS. EARLY AFTERNOON ACARS SOUNDINGS SHOWED ELY WINDS IN THE LOW LEVELS INCREASING TO ABOUT 25 KT AT 10 KFT AND WLY WINDS ALOFT. OFFSHORE GRADIENTS WITH ABOUT -10 MB SAN-TPH AND THERE WERE LOCAL GUSTY WINDS THROUGH AND BELOW MOUNTAIN CANYONS AND PASSES. THE MAINLY GRADIENT DRIVEN WINDS WILL CONTINUE LOCALLY STRONG BELOW CANYONS AND PASSES...MAINLY IN THE INLAND EMPIRE AND SANTA ANA MOUNTAINS. THE WINDS WILL GRADUALLY DECREASE THIS EVENING. HIGH CLOUDS WILL MOVE IN FROM THE SW TONIGHT AND SUN AS THE UPPER HIGH SHIFTS TO THE E AND A TROUGH APPROACHES FROM THE NW. MOISTURE IN THE LOW LEVELS WILL INCREASE LATE SUN NIGHT AND MON AS THE TROUGH MOVES ONSHORE RESULTING IN AN INCREASING CHANCE OF SHOWERS...MAINLY OVER AND W OF THE MOUNTAINS. DECREASING CHANCE OF SHOWERS MON NIGHT AS THE TROUGH MOVES E. MOISTURE IS LIMITED WITH THIS SYSTEM SO PRECIPITATION TOTALS SHOULD GENERALLY BE LESS THAN A QUARTER INCH...WITH POSSIBLY A FEW LOCAL LARGER AMOUNTS NEAR W FACING MOUNTAIN SLOPES. THE SNOW LEVEL WILL START OUT WELL ABOVE 7000 FT BUT WILL LOWER TO 5000-6000 FT MON THEN LOWERING A BIT MORE MON NIGHT. GUSTY WINDS WILL ALSO ACCOMPANY THIS SYSTEM...MAINLY IN THE MOUNTAINS AND DESERTS. MUCH COOLER SUN AND MON. DECREASING CLOUDINESS AND WARMER TUE AS A SHORT WAVE RIDGE MOVES IN FROM THE W AND BRIEF WEAK OFFSHORE FLOW DEVELOPS. .LONG TERM (WED-SAT)... CONTINUED FAIR WED WITH ONLY MINOR TEMP CHANGES FROM TUE AS THE SHORT WAVE RIDGE MOVES INLAND. ANOTHER PAC TROUGH WILL BRING MORE CLOUDS...COOLING AND A CHANCE OF SHOWERS THU INTO FRI. HOWEVER...THE EXACT STRENGTH AND TIMING OF THIS SYSTEM ARE STILL UNCERTAIN. EXPECT DECREASING CLOUDINESS AND A LITTLE WARMING SAT AS THE LOW MOVES E. && .AVIATION... SEA BREEZE WILL BE AFFECTING ELEVATIONS BELOW FL010 UNTIL 1700 PST/0100 UTC. LOW LEVEL WIND SHEAR AND MODERATE TO OCCASIONAL SEVERE TURBULENCE OVER AND WEST OF MOUNTAINS UNTIL 2200 PST/0600 UTC DUE TO CONTINUING EAST WINDS 15-25 KT IN THE FL010-FL050 LAYER AND MOUNTAIN GAP WINDS GUSTING 35-40 KT. AFTER 2200 PST/0600 UTC UPPER LOW APPROACHING FROM THE SOUTHWEST WILL CAUSE THE WINDS BELOW FL100 TO BACK TO SOUTHEAST 10-15 KT. REGION SHOULD REMAIN CLOUD FREE BELOW FL140...HOWEVER ABOVE THIS LAYER THERE WILL BE THICKENING AND LOWERING CIRRO/ALTOSTRATUS LEADING TO LIGHT ICING IN CLOUDS BETWEEN FL150-FL200 IS POSSIBLE AFTER 0400 PST/1200 UTC SUNDAY. && .MARINE... A LARGE WEST NORTHWEST SWELL WILL MOVE INTO THE COASTAL WATERS LATE SUNDAY THROUGH TUESDAY AND BE ACCOMPANIED WITH VERY CHOPPY SEAS DUE TO STRONG NORTHWEST WINDS. SPRING TIDES ARE MODERATING AND DO NOT EXPECT WIDESPREAD OR SIGNIFICANT COASTAL FLOODING PROBLEMS...BUT MODERATE BEACH EROSION IS POSSIBLE FROM ENCINITAS SOUTHWARD TO IMPERIAL BEACH DURING THE HIGH TIDES. ALREADY ISSUED HIGH SURF ADVISORY. NEXT SIFT WILL LIKELY ISSUE THE SMALL CRAFT ADVISORIES. && .SGX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FOR THE INLAND EMPIRE AND SANTA ANA MOUNTAINS UNTIL 10 PM TONIGHT. SEE LAXNPWSGX. HIGH RIP CURRENT RISK AT THE BEACHES SUN AND MON. SEE LAXSRFSGX HIGH SURF ADVISORY IN EFFECT FOR SAN DIEGO BEACHES FROM 2 PM SUNDAY TO 2 PM PST TUESDAY. SEE LAXCFWSGX. && $$ PUBLIC...DVA AVIATION/MARINE...BALFOUR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1215 PM EST SAT FEB 17 2007 .AVIATION (18Z TAFS)... WIDESPREAD BANDS OF -SN CONTINUE OVER THE REGION...AND EXPECT THIS TO CONTINUE THROUGH THE AFTN HOURS AT THE TAF SITES. PREVAILING VSBYS SHOULD BE IN THE 3-5SM RANGE...BUT WITHIN BANDS OF HEAVIER SNOW THEY COULD DROP DOWN TO BELOW 1SM. OUTSIDE OF HEAVIER SNOW BANDS...CIGS ARE NOT TERRIBLY LOW...GENERALLY NO LESS THAN 1KFT AGL. BASED ON LATEST FCST SOUNDINGS AND UPSTREAM OBSERVATIONS...FEEL THAT CIGS WILL CONTINUE TO RANGE FROM 1-2KFT THROUGH THE EVENING HOURS. ONE CHANGE TO THE ONGOING TAFS WAS TO INCREASE WIND GUSTS THIS EVENING AND OVERNIGHT...AS COLD FRONT SWEEPS ACROSS THE REGION WINDS WILL TURN MORE W/NW AND GUST TO NEAR 25KTS. ALSO ADDED MENTION OF SOME P6SM -SHSN TOMORROW...AS FCST SOUNDINGS SHOW POTENTIAL FOR -SHSN...ESPECIALLY OVER SDF/LEX TAF SITES. CS && .MESO UPDATE... ONE ADDITIONAL NOTE: BASED ON OBSERVATIONS AROUND THE AREA...A LOT OF THE SNOW IS MELTING ON ROADWAYS...BUT STICKING TO GRASSY SURFACES AND ROOFTOPS. TEMPERATURES NEAR FREEZING PLUS TREATMENTS BY HIGHWAY DEPTS ARE HELPING MELT SNOW ON PRIMARY ROADWAYS. WILL CONTINUE ADVISORY BUT HAVE MENTIONED SPECIFICALLY IN THE ZONES THAT MOST OF THE SNOW ACCUMULATION WILL BE ON GRASSY SURFACES AND UNTREATED ROADWAYS. EVEN SO...HEAVY SNOW BURSTS COULD STILL RESULT IN SLICK SPOTS...SOMETHING TO WATCH. REMAINDER OF PREVIOUS DISCUSSION BELOW: REGIONAL RADAR MOSAIC SHOWING A HEALTHY BATCH OF SNOW OVER THE LOWER OHIO VALLEY ASSOC WITH INCOMING CLIPPER SYSTEM...BEST COVERAGE AND HIGHEST INTENSITIES FROM ROUGHLY I-65 WEST INTO WRN KY/SRN IL/SW IN AS OF 1545Z. BANDS OF SNOW HAVE BEEN PRODUCING QUICK ACCUMS OVER WRN PARTS OF THE CWA...WITH VISIBILITIES DOWN TO BELOW ONE HALF MILE BASED ON SFC OBS AND WEBCAMS. CALLS TO SPOTTERS AND COOPERATIVE OBSERVERS INDICATE A WIDESPREAD 2" SNOWFALL THUS FAR ROUGHLY WEST OF A BWG-HARDINSBURG-ENGLISH LINE...WITH A RAPID DROP OFF TO THE EAST DUE TO EARLIER DRY LOW LEVEL AIRMASS. SEE LOCAL STORM REPORTS FOR SPECIFIC REPORTS. RADAR TRENDS INDICATE THAT MOST SUBSTANTIAL PRECIP WILL LIKELY AFFECT LOCATIONS ALONG AND SOUTH OF I-64 THROUGH THE AFTN HOURS... THOUGH IT WILL LIKELY BE MORE SHOWERY/BANDED IN NATURE. ONE INTERESTING FEATURE PRESSING EASTWARD THROUGH FAR WRN KY...THAT ON EARLIER RADAR IMAGES COULD BE CALLED A "SQUALL LINE OF SNOW"...JUST HAD THAT LOOK TO IT. THIS WILL AFFECT SRN PORTIONS OF THE CWA INTO EARLY AFTN. BASED ON FCST SOUNDINGS FROM 12Z RUC MOST OF THE PRECIP THIS AFTN SHOULD BE IN THE FORM OF SNOW. HOWEVER...EARLIER ACARS SOUNDINGS AT MEMPHIS SEEMED TO SUGGEST THAT RUC IS A TOUCH TOO COOL IN THE BOUNDARY LAYER. THEREFORE WILL CONTINUE MENTION THAT RAIN MAY MIX IN WITH SNOW AT TIMES THIS AFTN OVER SRN KY. REGARDING AMOUNTS...BASED ON CURRENT REPORTS AND UPSTREAM PRECIP... WILL INCREASE TOTAL SNOWFALL AMOUNTS INTO THE 2-3" RANGE FOR MOST OF THE CWA. DUE TO BANDED/SHOWERY NATURE TO PRECIP...AMOUNTS WILL LIKELY VARY A LOT OVER SHORT DISTANCES...AND THERE COULD BE LOCALLY HIGHER AMOUNTS. SNOW WILL ALSO COME DOWN HEAVY AT TIMES GIVEN SOME RADAR RETURNS APPROACHING 40DBZ...HANDLING THIS WITH SPECIAL WX STATEMENTS. TWO AREAS THAT MAY SEE LESS ARE THE FAR NORTHERN COUNTIES (NEAR MADISON) BASED SOLELY ON RADAR INDICATIONS OF A RELATIVE MIN IN PRECIP COVERAGE...AND ALONG THE KY/TN LINE WHERE A RA/SN MIX MAY OCCUR. WILL SIMPLY MENTION THESE POSSIBILITIES IN THE WSW...LEAVING THE ALIGNMENT/TIMES THE SAME AS THEY ARE NOW. I DID INCREASE THE WIND GUSTS TONIGHT INTO THE 20-25KT RANGE BASED ON UPSTREAM OBSERVATIONS OVER MO/IL. IT`S NOW SNOWING PRETTY GOOD HERE AT THE WFO WITH DECENT SIZED FLAKES. UPDATED FCST/HEADLINES SHOULD BE OUT BY 1130 AM EST. CS && .SHORT TERM (TODAY AND TONIGHT)... A WEAKENING SURFACE LOW ALONG THE IOWA/MISSOURI BORDER AT 06Z WILL SLIDE SOUTHEAST TODAY...OPENING UP INTO A TROF BY AFTERNOON AS IT PUSHES UP THE OHIO VALLEY AND THEN CROSSES THE APPALACHIANS THIS EVENING. TWO UPPER LEVEL SHORTWAVE TROFS THAT ARE READILY VISIBLE IN SATELLITE IMAGERY WILL BE PASSING OVERHEAD. THE FIRST IMPULSE WAS LOCATED NEAR PADUCAH AT 06Z. THE SECOND...SLIGHTLY STRONGER...WAVE WAS JUST NORTH OF KANSAS CITY. THE FIRST UPPER DISTURBANCE WILL BRING A BATCH OF SNOW ACROSS THE CWFA EARLY THIS MORNING. THE SNOW MAY BECOME MODERATE AT TIMES BUT IS MOVING QUICKLY AND ANYTHING MORE THAN LIGHT SNOW WOULD ONLY LAST FOR A BRIEF PERIOD OF TIME. ACCUMULATIONS WITH THIS FIRST AREA OF SNOW SHOULD BE AROUND AN INCH. WITH SURFACE TEMPERATURES QUITE COLD FROM THE RECENT CHILLY WEATHER THE SNOW SHOULD HAVE NO PROBLEM STICKING SO SOME SLICK ROADS MAY DEVELOP THIS MORNING. AFTER A BREAK IN THE SNOW LATE THIS MORNING AND EARLY THIS AFTERNOON...THE NEXT BATCH OF LIGHT SNOW WILL MOVE THROUGH THE REGION MID-AFTERNOON INTO EARLY EVENING. THIS NEXT BATCH OF SNOW WILL ALSO BE CAPABLE OF DROPPING AROUND AN INCH OF ACCUMULATION. MOS TEMPERATURES AT 06Z WERE ALMOST ALL RUNNING TOO COOL... ESPECIALLY OVER SOUTHERN KENTUCKY. LOOKING AT POSSIBLE AFTERNOON HIGHS...IT SEEMS SOUTHERN KENTUCKY SHOULD BE ABLE TO GET A FEW DEGREES ABOVE FREEZING. THEREFORE SOME RAIN MAY MIX IN WITH THE SNOW...LIMITING ACCUMULATIONS THERE. SNOW WILL GRADUALLY DEPART FROM WEST TO EAST THIS EVENING. WITH THE SNOW LINGERING A BIT LONGER IN THE BLUE GRASS (LEXINGTON) AREA TOTAL ACCUMULATIONS THERE WILL LIKELY BE THE HIGHEST IN CENTRAL KENTUCKY...AROUND 2 TO AS MUCH AS 2 AND A HALF INCHES. THESE AMOUNTS ARE IN GENERAL AGREEMENT WITH HPC THINKING WHICH INDICATES AMOUNTS OF 1 TO 2 INCHES TODAY. WINDS WILL SHIFT TO THE WEST THIS AFTERNOON AND NORTHWEST THIS EVENING AND WILL BECOME SOMEWHAT BREEZY...WITH A FEW GUSTS TO 20 OR 25 MPH POSSIBLE. AS TEMPERATURES DROP INTO THE TEENS THIS WILL CAUSE WIND CHILLS TO FALL INTO THE SINGLE DIGITS BY LATE TONIGHT. 13 .LONG TERM (SUNDAY-FRIDAY)... A LOW PRESSURE SYSTEM WILL BE MOVING WELL NORTHEAST OF THE AREA BY SUNDAY MORNING WITH ONLY LIGHT SNOW...MAINLY OVER THE EAST LINGERING BEHIND THE LOW. THUS MAIN CONCERNS IN THE LONGER TERM WILL BE ENDING OF PRECIPITATION...HOW COLD FOR SUNDAY NIGHT BEFORE A WARMING TREND SETS IN OVER THE AREA...AND THEN PRECIPITATION WITH THE NEXT SYSTEM AT MID WEEK. SUNDAY THROUGH MONDAY.... AS MENTIONED ABOVE...MOST OF THE SNOW WILL HAVE ENDED OVER THE AREA BY 12Z WITH ONLY LINGERING LIGHT SNOW OVER THE EAST AND NORTHEAST. THIS WILL DECREASE RAPIDLY DURING THE MORNING AS THE LOW CONTINUES TO MOVE AWAY AND HIGH PRESSURE BEGINS TO NUDGE INTO CENTRAL KENTUCKY. WITH LOWER CLOUDS PERSISTING CANNOT RULE OUT A FEW FLURRIES DEVELOPING BUT THESE SHOULD NOT BE SIGNIFICANT. CLOUDS WILL BEGIN TO DECREASE DURING THE DAY SUNDAY WITH SKIES BECOMING PARTLY CLOUDY TO MOSTLY CLEAR OVER THE ENTIRE REGION OVERNIGHT. COLDEST AIR WILL BE OVER CENTRAL KENTUCKY SUNDAY MORNING BUT WITH LIGHT WINDS AND MOSTLY CLEAR SKIES...THERE WILL BE GOOD RADIATIONAL COOLING SUNDAY NIGHT. TEMPERATURES WILL FALL RAPIDLY AFTER SUNSET... BUT AS THE SURFACE HIGH MOVES EAST...WINDS WILL BECOME SOUTHERLY AND INCREASE SLIGHTLY...SLOWING THE COOLING. HAVE RAISED MINS UP A FEW DEGREES FOR THIS REASON. UPPER FLOW BECOMES MORE ZONAL ON MONDAY AND THERE WILL BE PLENTY OF SUNSHINE BEFORE CLOUDS BEGIN TO INCREASE AHEAD OF NEXT SYSTEM MONDAY NIGHT. SOUTHERLY WINDS AROUND THE BACK SIDE OF THE HIGH MOVING OFF THE EAST COAST WILL BRING WARMER AIR INTO THE LOWER OHIO VALLEY WITH TEMPERATURES RISING INTO THE 40S. WILL GO SLIGHTLY BELOW MOS GUIDANCE. MONDAY NIGHT THROUGH FRIDAY... NEXT SYSTEM MOVES EAST AHEAD OF A TROUGH ADVANCING EAST FROM THE PACIFIC NORTHWEST. CLOUDS WILL INCREASE RAPIDLY MONDAY NIGHT AND THE CLOUDS ALONG WITH A GOOD SOUTHERLY FLOW WILL KEEP TEMPERATURES FROM FALLING MUCH BELOW THE MID 30S. EXPECT TO SEE A CHANCE OF RAIN AT LEAST OVER THE WEST HALF BY TUESDAY MORNING. RAIN WILL INCREASE OVER THE AREA DURING THE DAY TUESDAY WITH A BETTER CHANCE TUESDAY NIGHT INTO WEDNESDAY AS A COLD FRONT ASSOCIATED WITH THE TROUGH PUSHES ACROSS THE REGION. THE PRECIPITATION WILL END EARLY WEDNESDAY EVENING...BEFORE TEMPERATURES FALL ENOUGH TO TURN THE PRECIPITATION BACK TO SNOW. HIGH PRESSURE WILL KEEP DRY WEATHER OVER THE AREA FOR THE REST OF THE WEEK. SCHOLZ && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 3 AM EST /2 AM CST/ TO 6 PM EST /5 PM CST/ FOR KYZ023>034-038-045-053-061>063-070>074. SNOW ADVISORY FROM 6 AM EST /5 AM CST/ TO 11 PM EST /10 PM CST/ FOR KYZ035>037-039>043-046>049-054>057-064>067-075>078-081-082. IN...SNOW ADVISORY FROM 3 AM EST /2 AM CST/ TO 6 PM EST /5 PM CST/ FOR INZ076>079-083-084-089>092. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1145 AM EST SAT FEB 17 2007 .MESO UPDATE... ONE ADDITIONAL NOTE: BASED ON OBSERVATIONS AROUND THE AREA...A LOT OF THE SNOW IS MELTING ON ROADWAYS...BUT STICKING TO GRASSY SURFACES AND ROOFTOPS. TEMPERATURES NEAR FREEZING PLUS TREATMENTS BY HIGHWAY DEPTS ARE HELPING MELT SNOW ON PRIMARY ROADWAYS. WILL CONTINUE ADVISORY BUT HAVE MENTIONED SPECIFICALLY IN THE ZONES THAT MOST OF THE SNOW ACCUMULATION WILL BE ON GRASSY SURFACES AND UNTREATED ROADWAYS. EVEN SO...HEAVY SNOW BURSTS COULD STILL RESULT IN SLICK SPOTS...SOMETHING TO WATCH. REMAINDER OF PREVIOUS DISCUSSION BELOW: REGIONAL RADAR MOSAIC SHOWING A HEALTHY BATCH OF SNOW OVER THE LOWER OHIO VALLEY ASSOC WITH INCOMING CLIPPER SYSTEM...BEST COVERAGE AND HIGHEST INTENSITIES FROM ROUGHLY I-65 WEST INTO WRN KY/SRN IL/SW IN AS OF 1545Z. BANDS OF SNOW HAVE BEEN PRODUCING QUICK ACCUMS OVER WRN PARTS OF THE CWA...WITH VISIBILITIES DOWN TO BELOW ONE HALF MILE BASED ON SFC OBS AND WEBCAMS. CALLS TO SPOTTERS AND COOPERATIVE OBSERVERS INDICATE A WIDESPREAD 2" SNOWFALL THUS FAR ROUGHLY WEST OF A BWG-HARDINSBURG-ENGLISH LINE...WITH A RAPID DROP OFF TO THE EAST DUE TO EARLIER DRY LOW LEVEL AIRMASS. SEE LOCAL STORM REPORTS FOR SPECIFIC REPORTS. RADAR TRENDS INDICATE THAT MOST SUBSTANTIAL PRECIP WILL LIKELY AFFECT LOCATIONS ALONG AND SOUTH OF I-64 THROUGH THE AFTN HOURS... THOUGH IT WILL LIKELY BE MORE SHOWERY/BANDED IN NATURE. ONE INTERESTING FEATURE PRESSING EASTWARD THROUGH FAR WRN KY...THAT ON EARLIER RADAR IMAGES COULD BE CALLED A "SQUALL LINE OF SNOW"...JUST HAD THAT LOOK TO IT. THIS WILL AFFECT SRN PORTIONS OF THE CWA INTO EARLY AFTN. BASED ON FCST SOUNDINGS FROM 12Z RUC MOST OF THE PRECIP THIS AFTN SHOULD BE IN THE FORM OF SNOW. HOWEVER...EARLIER ACARS SOUNDINGS AT MEMPHIS SEEMED TO SUGGEST THAT RUC IS A TOUCH TOO COOL IN THE BOUNDARY LAYER. THEREFORE WILL CONTINUE MENTION THAT RAIN MAY MIX IN WITH SNOW AT TIMES THIS AFTN OVER SRN KY. REGARDING AMOUNTS...BASED ON CURRENT REPORTS AND UPSTREAM PRECIP... WILL INCREASE TOTAL SNOWFALL AMOUNTS INTO THE 2-3" RANGE FOR MOST OF THE CWA. DUE TO BANDED/SHOWERY NATURE TO PRECIP...AMOUNTS WILL LIKELY VARY A LOT OVER SHORT DISTANCES...AND THERE COULD BE LOCALLY HIGHER AMOUNTS. SNOW WILL ALSO COME DOWN HEAVY AT TIMES GIVEN SOME RADAR RETURNS APPROACHING 40DBZ...HANDLING THIS WITH SPECIAL WX STATEMENTS. TWO AREAS THAT MAY SEE LESS ARE THE FAR NORTHERN COUNTIES (NEAR MADISON) BASED SOLELY ON RADAR INDICATIONS OF A RELATIVE MIN IN PRECIP COVERAGE...AND ALONG THE KY/TN LINE WHERE A RA/SN MIX MAY OCCUR. WILL SIMPLY MENTION THESE POSSIBILITIES IN THE WSW...LEAVING THE ALIGNMENT/TIMES THE SAME AS THEY ARE NOW. I DID INCREASE THE WIND GUSTS TONIGHT INTO THE 20-25KT RANGE BASED ON UPSTREAM OBSERVATIONS OVER MO/IL. IT`S NOW SNOWING PRETTY GOOD HERE AT THE WFO WITH DECENT SIZED FLAKES. UPDATED FCST/HEADLINES SHOULD BE OUT BY 1130 AM EST. CS && .SHORT TERM (TODAY AND TONIGHT)... A WEAKENING SURFACE LOW ALONG THE IOWA/MISSOURI BORDER AT 06Z WILL SLIDE SOUTHEAST TODAY...OPENING UP INTO A TROF BY AFTERNOON AS IT PUSHES UP THE OHIO VALLEY AND THEN CROSSES THE APPALACHIANS THIS EVENING. TWO UPPER LEVEL SHORTWAVE TROFS THAT ARE READILY VISIBLE IN SATELLITE IMAGERY WILL BE PASSING OVERHEAD. THE FIRST IMPULSE WAS LOCATED NEAR PADUCAH AT 06Z. THE SECOND...SLIGHTLY STRONGER...WAVE WAS JUST NORTH OF KANSAS CITY. THE FIRST UPPER DISTURBANCE WILL BRING A BATCH OF SNOW ACROSS THE CWFA EARLY THIS MORNING. THE SNOW MAY BECOME MODERATE AT TIMES BUT IS MOVING QUICKLY AND ANYTHING MORE THAN LIGHT SNOW WOULD ONLY LAST FOR A BRIEF PERIOD OF TIME. ACCUMULATIONS WITH THIS FIRST AREA OF SNOW SHOULD BE AROUND AN INCH. WITH SURFACE TEMPERATURES QUITE COLD FROM THE RECENT CHILLY WEATHER THE SNOW SHOULD HAVE NO PROBLEM STICKING SO SOME SLICK ROADS MAY DEVELOP THIS MORNING. AFTER A BREAK IN THE SNOW LATE THIS MORNING AND EARLY THIS AFTERNOON...THE NEXT BATCH OF LIGHT SNOW WILL MOVE THROUGH THE REGION MID-AFTERNOON INTO EARLY EVENING. THIS NEXT BATCH OF SNOW WILL ALSO BE CAPABLE OF DROPPING AROUND AN INCH OF ACCUMULATION. MOS TEMPERATURES AT 06Z WERE ALMOST ALL RUNNING TOO COOL... ESPECIALLY OVER SOUTHERN KENTUCKY. LOOKING AT POSSIBLE AFTERNOON HIGHS...IT SEEMS SOUTHERN KENTUCKY SHOULD BE ABLE TO GET A FEW DEGREES ABOVE FREEZING. THEREFORE SOME RAIN MAY MIX IN WITH THE SNOW...LIMITING ACCUMULATIONS THERE. SNOW WILL GRADUALLY DEPART FROM WEST TO EAST THIS EVENING. WITH THE SNOW LINGERING A BIT LONGER IN THE BLUE GRASS (LEXINGTON) AREA TOTAL ACCUMULATIONS THERE WILL LIKELY BE THE HIGHEST IN CENTRAL KENTUCKY...AROUND 2 TO AS MUCH AS 2 AND A HALF INCHES. THESE AMOUNTS ARE IN GENERAL AGREEMENT WITH HPC THINKING WHICH INDICATES AMOUNTS OF 1 TO 2 INCHES TODAY. WINDS WILL SHIFT TO THE WEST THIS AFTERNOON AND NORTHWEST THIS EVENING AND WILL BECOME SOMEWHAT BREEZY...WITH A FEW GUSTS TO 20 OR 25 MPH POSSIBLE. AS TEMPERATURES DROP INTO THE TEENS THIS WILL CAUSE WIND CHILLS TO FALL INTO THE SINGLE DIGITS BY LATE TONIGHT. 13 .LONG TERM (SUNDAY-FRIDAY)... A LOW PRESSURE SYSTEM WILL BE MOVING WELL NORTHEAST OF THE AREA BY SUNDAY MORNING WITH ONLY LIGHT SNOW...MAINLY OVER THE EAST LINGERING BEHIND THE LOW. THUS MAIN CONCERNS IN THE LONGER TERM WILL BE ENDING OF PRECIPITATION...HOW COLD FOR SUNDAY NIGHT BEFORE A WARMING TREND SETS IN OVER THE AREA...AND THEN PRECIPITATION WITH THE NEXT SYSTEM AT MID WEEK. SUNDAY THROUGH MONDAY.... AS MENTIONED ABOVE...MOST OF THE SNOW WILL HAVE ENDED OVER THE AREA BY 12Z WITH ONLY LINGERING LIGHT SNOW OVER THE EAST AND NORTHEAST. THIS WILL DECREASE RAPIDLY DURING THE MORNING AS THE LOW CONTINUES TO MOVE AWAY AND HIGH PRESSURE BEGINS TO NUDGE INTO CENTRAL KENTUCKY. WITH LOWER CLOUDS PERSISTING CANNOT RULE OUT A FEW FLURRIES DEVELOPING BUT THESE SHOULD NOT BE SIGNIFICANT. CLOUDS WILL BEGIN TO DECREASE DURING THE DAY SUNDAY WITH SKIES BECOMING PARTLY CLOUDY TO MOSTLY CLEAR OVER THE ENTIRE REGION OVERNIGHT. COLDEST AIR WILL BE OVER CENTRAL KENTUCKY SUNDAY MORNING BUT WITH LIGHT WINDS AND MOSTLY CLEAR SKIES...THERE WILL BE GOOD RADIATIONAL COOLING SUNDAY NIGHT. TEMPERATURES WILL FALL RAPIDLY AFTER SUNSET... BUT AS THE SURFACE HIGH MOVES EAST...WINDS WILL BECOME SOUTHERLY AND INCREASE SLIGHTLY...SLOWING THE COOLING. HAVE RAISED MINS UP A FEW DEGREES FOR THIS REASON. UPPER FLOW BECOMES MORE ZONAL ON MONDAY AND THERE WILL BE PLENTY OF SUNSHINE BEFORE CLOUDS BEGIN TO INCREASE AHEAD OF NEXT SYSTEM MONDAY NIGHT. SOUTHERLY WINDS AROUND THE BACK SIDE OF THE HIGH MOVING OFF THE EAST COAST WILL BRING WARMER AIR INTO THE LOWER OHIO VALLEY WITH TEMPERATURES RISING INTO THE 40S. WILL GO SLIGHTLY BELOW MOS GUIDANCE. MONDAY NIGHT THROUGH FRIDAY... NEXT SYSTEM MOVES EAST AHEAD OF A TROUGH ADVANCING EAST FROM THE PACIFIC NORTHWEST. CLOUDS WILL INCREASE RAPIDLY MONDAY NIGHT AND THE CLOUDS ALONG WITH A GOOD SOUTHERLY FLOW WILL KEEP TEMPERATURES FROM FALLING MUCH BELOW THE MID 30S. EXPECT TO SEE A CHANCE OF RAIN AT LEAST OVER THE WEST HALF BY TUESDAY MORNING. RAIN WILL INCREASE OVER THE AREA DURING THE DAY TUESDAY WITH A BETTER CHANCE TUESDAY NIGHT INTO WEDNESDAY AS A COLD FRONT ASSOCIATED WITH THE TROUGH PUSHES ACROSS THE REGION. THE PRECIPITATION WILL END EARLY WEDNESDAY EVENING...BEFORE TEMPERATURES FALL ENOUGH TO TURN THE PRECIPITATION BACK TO SNOW. HIGH PRESSURE WILL KEEP DRY WEATHER OVER THE AREA FOR THE REST OF THE WEEK. SCHOLZ && .AVIATION (12Z TAFS)... A PAIR OF UPPER LEVEL WAVES WILL BRING LIGHT SNOW TO THE TAF SITES TODAY...TAPERING OFF EARLY THIS EVENING. CEILINGS AND VISIBILITIES WILL VARY QUITE A BIT TODAY...GOING BACK AND FORTH FROM VFR BETWEEN PATCHES OF SNOW TO BRIEFLY IFR WITHIN THE HEAVIER SNOW SHOWERS. FOR PREVAILING CONDITIONS KEPT THE TAFS GENERALLY MVFR. THE SNOW SHOULD TAPER OFF FROM WEST TO EAST THIS EVENING. WHILE BWG AND POSSIBLY SDF SHOULD LOSE THEIR LOW CEILING OVERNIGHT...MVFR CLOUDS WILL LIKELY HANG IN THROUGHOUT THE TAF PERIOD AT LEX. 13 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 3 AM EST /2 AM CST/ TO 6 PM EST /5 PM CST/ FOR KYZ023>034-038-045-053-061>063-070>074. SNOW ADVISORY FROM 6 AM EST /5 AM CST/ TO 11 PM EST /10 PM CST/ FOR KYZ035>037-039>043-046>049-054>057-064>067-075>078-081-082. IN...SNOW ADVISORY FROM 3 AM EST /2 AM CST/ TO 6 PM EST /5 PM CST/ FOR INZ076>079-083-084-089>092. && $$