Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 02/18/09

AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
500 AM PST MON FEB 16 2009 .DISCUSSION... VERTICALLY STACKED LOW PRESSURE SYSTEM REMAINS CENTERED NEAR 40N/129W THIS MORNING WHILE A NORTH TO SOUTH ORIENTED BAROCLINIC ZONE REMAINS NEARLY STATIONARY ACROSS THE INTERIOR OF NORTHERN CALIFORNIA. HEAVIEST PRECIPITATION CONTINUES TO BE FOCUSED INTO THE NORTH END OF THE SACRAMENTO VALLEY AND MOUNTAINS NORTH OF REDDING AND ALONG THE WEST SIDE OF THE SACRAMENTO VALLEY WHERE OROGRAPHIC ENHANCEMENT HAS BEEN THE STRONGEST WITH THE SOUTH TO SOUTHEAST LOW-LEVEL FLOW. AROUND 1.5 TO 2 INCHES OF RAIN HAS FALLEN IN THE PAST 24 HOURS ACROSS THE REDDING AREA WHILE UP TO 3.5 INCHES HAVE FALLEN IN THE MOUNTAINS TO THE NORTH. IN THE SACRAMENTO AREA...MOST 24 HOUR RAINFALL AMOUNTS HAVE BEEN AROUND 1/2 AN INCH WHILE VACAVILLE STANDS OUT WITH A LITTLE OVER AN INCH. MANY AREAS ON THE WEST SLOPES OF THE NORTHERN SIERRA HAVE ONLY SEEN AROUND 1/2 INCH TO AN INCH AS THE MAIN PRECIPITATION BAND HAS MOSTLY STAYED TO THE WEST. THE OFFSHORE LOW IS FORECAST TO EDGE A LITTLE CLOSER TO THE COAST TODAY WHICH WILL INCH THE BAROCLINIC ZONE FURTHER TO THE EAST BRINGING A RETURN OF MORE SIGNIFICANT PRECIPITATION TO THE NORTHERN SIERRA BY LATER THIS MORNING. EXPECT TO SEE MORE IMPRESSIVE PRECIPITATION AMOUNTS (FOR THIS YEAR) THE NEXT 24 HOURS AS THE REGION WILL REMAIN UNDER MODERATELY STRONG UPWARD VERTICAL MOTION TO THE NORTH OF THE UPPER JET THROUGH SOCAL. STILL SEEING SOME GUSTY SOUTHEASTERLY WINDS IN THE VALLEY EARLY THIS MORNING AS THE NEXT FRONTAL BAND MOVES ONTO THE COAST. SURFACE GRADIENTS ARE MUCH WEAKER THAN 24 HOURS AGO...BUT KDAX VAD WIND PROFILE HAS SHOWN SOME STRENGTHENING OF THE LOW-LEVEL JET THE PAST COUPLE OF HOURS. HOWEVER...GRADIENTS ARE EXPECTED TO WEAKEN FURTHER BY 18Z...SO WHAT WE/RE SEEING NOW IS PROBABLY GOING TO BE THE STRONGEST WINDS TODAY. UPPER LOW MOVES OVERHEAD NORTHERN CALIFORNIA TUESDAY AS SURFACE LOW CONTINUES TO FILL. WE/LL LIKELY CONTINUE TO SEE LOTS OF SHOWERS UNDER THE COLD AND UNSTABLE AIRMASS...AND A FEW THUNDERSTORMS CANNOT BE RULED OUT FOR THE VALLEY AND FOOTHILLS IF LOCAL CLEARING ALLOWS FURTHER DESTABILIZATION. THE NORTHERN SIERRA WILL LIKELY SEE PLENTY OF SNOW WITH THIS PATTERN AS MORE FAVORABLE UPSLOPE FLOW DEVELOPS AND MID-LEVEL LAPSE RATES STEEPEN. LOOKS LIKE WE/LL FINALLY BEGIN TO SEE MORE SETTLED WEATHER RETURN WEDNESDAY AS RIDGING BUILDS ACROSS NORTHERN CALIFORNIA AHEAD OF ANOTHER LOW THAT DROPS SOUTHWARD FROM THE GULF OF ALASKA ALONG 140W. && .EXTENDED DISCUSSION (THURSDAY THROUGH MONDAY)... SHORTWAVE RIDGE STILL HANGING ON OVER THE WEST COAST THURSDAY THROUGH FRIDAY WITH SPLIT FLOW OVER THE PACIFIC THAT HAS LEFT A CUTOFF LOW NEAR 140W. A VIGOROUS SHORT WAVE TROUGH DESCENDS OUT OF THE GULF OF ALASKA ON SAT AND ACTS AS A KICKER...BEGINNING PRECIP OVER THE REGION SAT AFTN AND CONTINUING THROUGH MONDAY. THE ECMWF AND GEM KEPT THE LOW BETWEEN 130W AND 140W AND A KICKER FINALLY PULLS THE LOW TOWARD THE COAST ON MON. NEEDLESS TO SAY...THE NUMERICAL MODELS ARE HAVING DIFFICULTY WITH THE HANDLING OF THIS SYSTEM NEXT WEEKEND. WENT WITH PERSISTENCE AND GFS FOR OUR PRECIP FORECAST. && .AVIATION... STEADY RAIN CONTINUES IN THE VALLEY AND NRN MTNS TODAY WITH PRECIP TO REACH HYR SIERNEV LATER TODAY AS PROGRESSION OF LOW IS SLOW. VFR CIGS OVER THE VALLEY WITH LCL MVFR DURING HEAVIER SHOWERS WITH LOWERED VSBYS BETWEEN 3-5SM. BREEZY SLY WIND SRN SAC AND NRN SJ VALLEY THRU AROUND 22-00Z. RADAR SHOWS 1000FT WIND 16030KT OVER CENTRAL VALLEY...CREATING LLWS OVER NRN SAC VALLEY DUE TO N SFC FLOW. AMDAR SOUNDING SHOW FREEZING LVL AROUND 4500FT DECREASING TO NEAR 4000FT BY TUE MORN. RIDGETOP GUSTS ACROSS THE SIERRA LIKELY TO BE 40 KTS. SHSN COULD CAUSE MTNS OBSCURATION WITH IFR/MVFR CIGS AND VSBYS 1-3SM...LOCALLY LOWER. AT KSMF...A BAND OF STEADY -RA CONTINUES TO AFFECT THE TERMINAL AREA TODAY WITH RA WEST AROUND THE BAY AREA INTO WRN DELTA. SSE WIND G25-30KT GRADUALLY WEAKENING THRU 22Z. JMC && .STO WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 4 AM PST WEDNESDAY FOR WEST SLOPE NORTHERN SIERRA NEVADA-WESTERN PLUMAS COUNTY/LASSEN PARK. WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST TUESDAY FOR MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO NORTHERN LAKE COUNTY-SHASTA LAKE AREA/NORTHERN SHASTA COUNTY. WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO NORTHERN LAKE COUNTY-SHASTA LAKE AREA/NORTHERN SHASTA COUNTY. WINTER WEATHER ADVISORY UNTIL 4 PM PST TUESDAY FOR BURNEY BASIN/EASTERN SHASTA COUNTY. && $$
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
910 PM EST TUE FEB 17 2009 ...SEVERE WEATHER POSSIBLE WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT... .DISCUSSION...00 UTC SURFACE ANALYSIS HAS SEVERAL INTERESTING FEATURES THIS EVENING. A 991 MB SURFACE LOW WAS ANALYZED NEAR TOPEKA KANSAS. A WARM FRONT EXTENDED ACROSS CENTRAL OKLAHOMA SOUTHEASTWARD INTO NORTHERN LA AND SOUTH CENTRAL MS. THIS WARM FRONTAL BOUNDARY ESSENTIALLY INDICATES THE LEADING EDGE OF GREATER THAN 50 DEGREE DEWPOINTS AND THE SOUTHERLY WIND SHIFT. MUCH MORE MOIST AIR WAS LOCATED ACROSS COASTAL TEXAS WHERE DEWPOINTS WERE IN THE MID 60S. A DRY LINE WAS ANALYZED ACROSS CENTRAL TEXAS FROM NEAR THE EASTERN PORTION OF THE PANHANDLE SOUTHWARD TOWARD DEL RIO. THE COLD FRONT WAS LOCATED FURTHER WEST ACROSS THE WESTERN PANHANDLE DOWN INTO SOUTHEASTERN NEW MEXICO. A SECOND COLD FRONT WAS ACROSS SOUTH DAKOTA...INDICATING THE LEADING EDGE OF THE TRULY COLD AIRMASS THAT WILL ARRIVE BY THE END OF THE WEEK. VAPOR IMAGERY AND 500 MB ANALYSIS AT 00 UTC SHOWS A RATHER COMPLEX PATTERN ACROSS THE NORTHERN CONUS WITH ESSENTIALLY ZONAL FLOW ACROSS THE SOUTHEASTERN CONUS. A DEEPENING TROF IS NOW MOVING INTO NORTH DAKOTA AND PUSHING OFF TO THE SOUTHEAST. AS THIS TROF DEEPENS...THE STORM SYSTEM ACROSS THE CENTRAL PLAINS WILL PUSH FURTHER EAST AND BRING THE POTENTIAL FOR STORMY WEATHER TO OUR REGION. LOCALLY...THE 00 UTC KTAE SOUNDING SHOWS A VERY DRY LAYER FROM THE SURFACE UP TO ABOUT 750 MB WITH A MOIST LAYER ABOVE. RADAR DATA FROM AROUND THE REGION SHOW SOME LIGHT RETURNS...BUT SURFACE OBSERVATIONS HAVE ONLY SHOWN VERY LIGHT RAIN. ONLY TRACE AMOUNTS HAVE BEEN REPORTED...AND THE DRIER AIR IN THE LOW LEVELS IS LIKELY EVAPORATING MUCH OF THE PRECIP BEFORE IT CAN REACH THE SURFACE. THE BEST CHANCE FOR MEASURABLE RAINFALL WILL LIKELY BE ALONG THE US-82 CORRIDOR THIS EVENING AND POINTS NORTHWARD. THE BIG FOCUS WILL SHIFT TO THE POTENTIAL FOR STRONG TO SEVERE STORMS ON WEDNESDAY AFTERNOON/NIGHT ACROSS THE REGION. THE AREA CONTINUES TO BE OUTLINED IN A SLIGHT RISK. THIS SYSTEM CONTINUES TO GENERATE VERY FAVORABLE KINEMATIC PROFILES /0-6 KM SHEAR VALUES OF 55 TO 65 KNOTS/ AHEAD OF THE FRONTAL BOUNDARY WITH A 45 TO 50 KNOT 850 MB JET PRESENT. THE INSTABILITY CONTINUES TO BE THE MAIN CONCERN AND HOW MUCH WILL BE PRESENT REMAINS VERY UNCERTAIN. THE NAM INDICATES MUCAPES THROUGHOUT THE EVENING HOURS BETWEEN 500 J/KG AND 1000 J/KG...WHEREAS THE GFS SHOWS VALUES LESS THAN 500 J/KG. THE OVERALL TREND IN THE MODELS HAS BEEN FOR A LITTLE MORE INSTABILITY...SO I WOULDN`T BE SURPRISED TO SEE A FEW SEVERE STORMS WEDNESDAY AFTERNOON AND EVENING...ESPECIALLY ACROSS THE WESTERN HALF OF OUR REGION WHERE THE COMBINATION OF INSTABILITY AND SHEAR WILL BE MAXIMIZED. AREAS FURTHER EAST...GENERALLY EAST OF AN ALBANY TO TALLAHASSEE LINE SHOULD NOT LET THEIR GUARD DOWN EITHER...EVEN THOUGH THE ATTENDANT LINE OF STORMS MAY GRADUALLY WEAKEN AFTER MIDNIGHT. CURRENT FORECAST FOR THIS TIME RANGE INCLUDES MENTION OF SEVERE STORMS...AND SEE NO REASON TO MAKE ANY CHANGES THERE AT THIS TIME. REMAINDER OF SHORT TERM FORECAST LOOKS GOOD...MAY MAKE A FEW UPDATES TO THE ZONES TO HANDLE THE LIGHT PRECIP OCCURRING PRIOR TO MIDNIGHT...BUT NO OTHER SUBSTANTIVE CHANGES NEEDED AT THIS TIME. HAVE A GREAT NIGHT! && .AVIATION...SMOKE FROM YET ANOTHER PRESCRIBED BURN IN N CENTRAL WAKULLA COUNTY IS BEING TRANSPORTED TOWARD THE NW. AIRCRAFT APPROACHING TLH FROM THE SW OR W MAY NEED TO DIVERT AROUND THE PLUME. AT THIS TIME...WE DO NOT ANTICIPATE THE SMOKE FUMIGATING TO THE SURFACE AT THIS TERMINAL OVERNIGHT AS WINDS WILL MAINTAIN AN ELY COMPONENT. WINDS WILL INCREASE CONSIDERABLY WITHIN 1-2 KFT OF THE GROUND BEFORE DAYBREAK AND LOW LEVEL WIND SHEAR IS FORECAST AT ALL TERMINALS. THE SHEAR WILL BE MAXIMIZED ROUGHLY FROM 08-14Z. AFTER THAT TIME...THE ELEVATED WINDS WILL MIX DOWN IN SSWLY GUSTS THROUGH THE DAY. CONVECTION ASSOCIATED WITH A PRE-FRONTAL SQUALL LINE WILL BEGIN TO IMPACT THE TERMINALS TOWARD THE END OF THE TAF PERIOD. THE BEST CHANCE FOR STORMS WILL OCCUR AFTER THE END OF THE TAF PERIOD AT TLH AND VLD. CEILINGS WILL LOWER THROUGH THE DAY...BUT REMAIN VFR OUTSIDE OF TS...WHERE MVFR CIGS ARE FORECAST. && .MARINE...WINDS ARE GRADUALLY INCREASING THIS EVENING AND ARE JUST ABOUT INTO THE EXERCISE CAUTION CATEGORY ACROSS THE WESTERN LEGS. DO NOT EXPECT ADVISORY CONDITIONS PRIOR TO 12Z...SO WILL LET MIDNIGHT SHIFT HANDLE THE ISSUANCE OF ANY ADVISORY OVER THE WATERS...BUT IT LOOKS LIKE IT WILL BE NEEDED BY THE AFTERNOON HOURS ON WEDNESDAY. && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY EVENING FOR THE FOLLOWING ZONES: BAY...CALHOUN...COASTAL WALTON...DIXIE...FRANKLIN...GADSDEN...GULF...HOLMES... INLAND WALTON...JACKSON...JEFFERSON...LAFAYETTE...LEON... LIBERTY...MADISON...TAYLOR...WAKULLA...WASHINGTON. GM...NONE. && $$ AVIATION...WOOL REST OF DISCUSSION...GODSEY
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
553 AM CST MON FEB 16 2009 .DISCUSSION... 401 AM CST FORECAST CONCERNS ARE FEW IN NEAR TERM WITH LAKE EFFECT CLOUDS AND FLURRIES RAPIDLY DISSIPATING OVER NORTHWEST INDIANA. MID WEEK STORM SYSTEM CONTINUES TO POSE SIGNIFICANT CHALLENGES AS MODELS CONTINUE GRAPPLE WITH DETAILS OF EVOLUTION AND SURFACE LOW TRACK...WHICH HAS LARGE IMPLICATIONS ON FORECAST FOR NORTHERN ILLINOIS AND NORTHWEST INDIANA. REGIONAL RADAR MOSAIC HAS DEPICTED GRADUAL DECREASE IN COVERAGE AND INTENSITY OF LIGHT LAKE EFFECT SNOW SHOWERS OVER FAR SOUTHERN LAKE MICHIGAN OVER THE LAST SEVERAL HOURS. THIS BAND...WHICH WAS OVER LAKE/PORTER AND EASTERN COOK COUNTY LAST EVENING...HAS WEAKENED AND SHIFTED EAST INTO WFO IWX FORECAST AREA EARLY THIS MORNING. GOES 11-3.9 MICRON CHANNEL STILL INDICATES A LITTLE LAKE INDUCED STRATOCU INTO NORTHERN PORTER COUNTY AND COULD SEE A STRAY FLURRY FROM THESE CLOUDS EARLY THIS MORNING BEFORE THEY TOO DISSIPATE/SHIFT EAST AS LOW WIND FIELD WEAKENS/BACKS NORTHWEST WITH APPROACH OF HIGH PRESSURE FROM THE WEST. FARTHER TO THE WEST...AREA OF MID CLOUDS ACROSS IA/MN IN LOW LEVEL WARM ADVECTION ZONE WEST OF SURFACE RIDGE EXPECTED TO REMAIN MAINLY NORTHWEST OF FORECAST AREA UNTIL LATE TODAY AS LOW LEVEL JET ORIENTED INTO WISCONSIN AND ISENTROPIC FORECASTS FROM NAM INDICATE ONLY GRADUAL DECREASE IN CONDENSATION PRESSURE DEFICITS ACROSS NORTHERN IL THROUGH THIS AFTERNOON. EXPECT MORE SUNSHINE TODAY WITH TEMPS JUST A FEW DEGREES WARMER THAN YESTERDAY...AS SURFACE HIGH PRESSURE RIDGE MOVES ACROSS THE AREA AND STRONGER RETURN FLOW ON BACK SIDE OF RIDGE REMAINS WEST OF US FOR MUCH OF THE DAY. TEMPS DO GRADUALLY MODERATE TONIGHT/TUESDAY AS SOUTHERLY WINDS BECOME BETTER ESTABLISHED INTO IL/IN...WITH GRADUAL INCREASE IN HIGH/MID CLOUDS. MODEL FORECASTS CONTINUE TO STRUGGLE WITH DETAILS OF EVOLUTION OF STORM SYSTEM EXPECTED TO AFFECT THE MIDWEST MIDWEEK. SHORT WAVE DISTURBANCE CURRENTLY DIGGING INTO BASE OF UPPER TROUGH OFF THE CALIFORNIA COAST IS FORECAST TO ROTATE ACROSS THE SOUTHWEST TONIGHT AND EMERGE FROM THE CENTRAL/SOUTHERN ROCKIES ON TUESDAY. WHILE GUIDANCE HAS SLOWED THIS PROGRESSION A BIT FROM EARLIER RUNS...ALL MEMBERS OF THE 25 MAN ROSTER ARE SIMILAR IN THIS DEPICTION WITH SURFACE LOW DEVELOPMENT INTO WESTERN KANSAS BY TUESDAY EVENING. SOUTHERN EXTENT OF HIGH PRESSURE RIDGE MOVING THROUGH THE MIDWEST KEEPS THE GULF BLOCKED OFF A BIT INITIALLY...THOUGH APPEARS LOW LEVEL MOISTURE SHOULD BEGIN TO STREAM NORTHWARD AS PLAINS LOW MOVES EAST ACROSS KANSAS TUESDAY NIGHT. THUS HAVE BACKED OFF POPS/QPF ACROSS EASTERN 2/3 OF FORECAST AREA DURING THE DAY TUESDAY...WITH FORECAST SOUNDINGS SUPPORTING PERHAPS A MIX OF LIGHT RAIN/SNOW INITIALLY GIVEN DRY LOW LEVELS. LOW LEVEL THICKNESS FIELDS FROM NAM/GFS/ECMWF STILL INDICATE LOW LEVELS SHOULD WARM ENOUGH FOR MAINLY RAIN BY TUESDAY NIGHT ACROSS MOST OF THE FORECAST AREA... THOUGH THICKNESS REMAINS MARGINAL IN VICINITY OF IL/WIS STATE LINE SUGGESTING EITHER RAIN/SNOW OR MIX. SIGNIFICANT FORECAST PROBLEM HOWEVER IS THAT MOST OF THE MODELS HAVE FLIP/FLOPPED OVER THE LAST SEVERAL RUNS...WITH RESPECT TO EVENTUAL TRACK OF SURFACE LOW THROUGH THE MIDWEST/GREAT LAKES REGION. BY 60 HOURS...12Z WED...VARIOUS SOLUTIONS AND ENSEMBLE MEMBERS LOCATE SURFACE LOW ANYWHERE FROM CENTRAL MISSOURI TO CHICAGO. AND THERE HAS BEEN LITTLE RUN TO RUN CONTINUITY IN ANY PARTICULAR MODEL TO LEND CONFIDENCE TO ANY PARTICULAR SOLUTION. GIVEN MODEL SPREAD AT THIS POINT...HAVE CHOSEN TO MAINTAIN CHARACTER OF GOING FORECAST...WHICH AGREES RATHER WELL WITH 00Z GFS/UKMET SOLUTIONS. THUS SCENARIO OF LIGHT PRECIP DEVELOPING TUESDAY AS RAIN OR RAIN/SNOW MIX...CHANGING TO MAINLY RAIN TUESDAY NIGHT EXCEPT NEAR IL/WI BORDER...THEN CHANGING TO SNOW FROM THE NORTHWEST ON WEDNESDAY AS SYSTEM MOVES THROUGH AND COLD AIR IS ENTRAINED INTO THE REAR FLANK OF STORM. ONLY REAL CHANGES TO FORECAST AT THIS TIME IS TO BEEF UP POPS WEDNESDAY NIGHT/THURSDAY AS SECOND NORTHERN STREAM SHORT WAVE DIGS INTO AMPLIFYING TROUGH AND PRESENTS FURTHER POTENTIAL FOR LIGHT SNOW/SNOW SHOWERS...AND HAVE LOWERED TEMPS A BIT THURSDAY ONWARD AS ARCTIC AIR OOZES SOUTHEAST ACROSS THE AREA. HAVE MAINTAINED MENTION OF THUNDER TUESDAY NIGHT/WEDNESDAY ACROSS SOUTHERN PARTS OF CWA AS GFS INDICATES VERY STEEP MID LEVEL LAPSE RATES...8 TO 9 DEG/KM...AND SEVERAL HUNDRED J/KG OF ELEVATED CAPE AVAILABLE. WILL LIKELY SEE AT LEAST A FEW INCHES OF SNOW ACROSS NORTHERN IL WEDNESDAY/WEDNESDAY NIGHT...THOUGH CONFIDENCE VERY LOW WITH RESPECT TO AMOUNTS AT THIS TIME. SUSPECT THAT AS THIS SHORT WAVE COMES ASHORE TONIGHT THAT MODELS WILL GET A MUCH BETTER HANDLE ON DEVELOPMENT OF THIS SYSTEM AS IT ENCOUNTERS DENSER AIRCRAFT/RAOB NETWORK. RATZER && .AVIATION... 552 AM CST 1200 UTC TAFS...SURFACE HIGH PRESSURE ACROSS THE MID/UPPER MISSISSIPPI RIVER VALLEY WILL PROVIDE LIGHT WINDS TODAY. SOUTHWEST WINDS WILL DEVELOP TOWARD MIDDAY AS THE HIGH BEGINS TO SLIDE TO THE EAST...WITH SPEEDS GENERALLY AROUND 5 KNOTS THIS AFTERNOON. BAND OF 6-8K FT CLOUDINESS ASSOCIATED WITH LOW LEVEL WARM ADVECTION IS NOTED EARLY THIS MORNING FROM CENTRAL IOWA INTO EASTERN MINNESOTA. THE STRONGEST WARM ADVECTION IS LIKELY TO REMAIN NORTH INTO WISCONSIN AND NOT EXPECTING THIS BAND OF CLOUDINESS TO EXTEND AS FAR SOUTH AS NORTHERN ILLINOIS THIS AFTERNOON. FOR SKY COVER TODAY...JUST EXPECTING SOME CIRRUS TO MOVE ACROSS THE AREA THIS AFTERNOON. MID LEVEL WARM ADVECTION WILL INCREASE TONIGHT WHICH SHOULD RESULT IN INCREASING COVERAGE OF MID AND HIGH CLOUDINESS. WINDS THIS EVENING WILL BACK TO THE SOUTH AND SPEEDS SHOULD INCREASE TO AROUND 10 KNOTS. EXPECTING GUSTINESS TO INCREASE BY MID MORNING TUESDAY WITH BETTER MIXING AND SOME GUSTS TO 20 KNOTS POSSIBLE. MARSILI && .MARINE... 315 AM CST THE MAIN MARINE FORECAST ISSUES ARE STRENGTHENING SOUTH TO SOUTHWEST WINDS TONIGHT AND POTENTIAL FOR GALES LATE WEDNESDAY AFTERNOON THROUGH THURSDAY. SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE WESTERN GREAT LAKES THIS MORNING WITH WIND SPEEDS GENERALLY LESS THAN 10 KNOTS. THE CENTER OF THIS HIGH WILL MOVE SOUTH OF LAKE MICHIGAN WHICH WILL RESULT IN WINDS BECOMING SOUTHWEST THIS AFTERNOON. AN UPPER LEVEL DISTURBANCE ACROSS SOUTHERN CANADA WILL ALLOW FOR WEAK LOW PRESSURE TO DEVELOP ACROSS NORTHERN MINNESOTA TODAY. FALLING PRESSURES ASSOCIATED WITH THIS LOW COMBINED WITH THE DEPARTING RIDGE SHOULD RESULT IN A STRONG ENOUGH SFC PRESSURE GRADIENT FOR SOME GUSTS TO 25 KNOTS TONIGHT INTO TUESDAY. A STRONGER LOW WILL THEN BEGIN TO DEVELOP ACROSS THE CENTRAL PLAINS TUESDAY NIGHT AND TRACK ACROSS FAR SOUTHERN LAKE MICHIGAN OR JUST SOUTH OF THE LAKE WEDNESDAY AFTERNOON. NORTHWEST GALES TO 40 KNOTS ARE LIKELY FROM LATE WEDNESDAY AFTERNOON INTO THURSDAY WITH STRONG COLD ADVECTION. A SECONDARY UPPER TROUGH WILL ALSO BE DIVING INTO THE WESTERN GREAT LAKES WEDNESDAY NIGHT DEEPENING THE LOW AS IT MOVES EAST OF LAKE MICHIGAN WHICH SHOULD ALSO SUPPORT LIKELIHOOD OF GALES. ONSET OF FORECASTED GALES STILL BEYOND THE WATCH PHASE AT THIS TIME SO NO HEADLINES WILL BE ISSUED THIS MORNING. WINDS AND WAVES SHOULD BEGIN TO DIMINISH THURSDAY EVENING. ANOTHER LOW IS EXPECTED TO MOVE ACROSS THE MID MISSISSIPPI RIVER VALLEY INTO THE OHIO RIVER VALLEY FRIDAY/SATURDAY RESULTING IN STRENGTHENING NORTH TO NORTHWEST WINDS TOWARD THE END OF THE FORECAST PERIOD. MARSILI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
401 AM CST MON FEB 16 2009 .DISCUSSION... 401 AM CST FORECAST CONCERNS ARE FEW IN NEAR TERM WITH LAKE EFFECT CLOUDS AND FLURRIES RAPIDLY DISSIPATING OVER NORTHWEST INDIANA. MID WEEK STORM SYSTEM CONTINUES TO POSE SIGNIFICANT CHALLENGES AS MODELS CONTINUE GRAPPLE WITH DETAILS OF EVOLUTION AND SURFACE LOW TRACK...WHICH HAS LARGE IMPLICATIONS ON FORECAST FOR NORTHERN ILLINOIS AND NORTHWEST INDIANA. REGIONAL RADAR MOSAIC HAS DEPICTED GRADUAL DECREASE IN COVERAGE AND INTENSITY OF LIGHT LAKE EFFECT SNOW SHOWERS OVER FAR SOUTHERN LAKE MICHIGAN OVER THE LAST SEVERAL HOURS. THIS BAND...WHICH WAS OVER LAKE/PORTER AND EASTERN COOK COUNTY LAST EVENING...HAS WEAKENED AND SHIFTED EAST INTO WFO IWX FORECAST AREA EARLY THIS MORNING. GOES 11-3.9 MICRON CHANNEL STILL INDICATES A LITTLE LAKE INDUCED STRATOCU INTO NORTHERN PORTER COUNTY AND COULD SEE A STRAY FLURRY FROM THESE CLOUDS EARLY THIS MORNING BEFORE THEY TOO DISSIPATE/SHIFT EAST AS LOW WIND FIELD WEAKENS/BACKS NORTHWEST WITH APPROACH OF HIGH PRESSURE FROM THE WEST. FARTHER TO THE WEST...AREA OF MID CLOUDS ACROSS IA/MN IN LOW LEVEL WARM ADVECTION ZONE WEST OF SURFACE RIDGE EXPECTED TO REMAIN MAINLY NORTHWEST OF FORECAST AREA UNTIL LATE TODAY AS LOW LEVEL JET ORIENTED INTO WISCONSIN AND ISENTROPIC FORECASTS FROM NAM INDICATE ONLY GRADUAL DECREASE IN CONDENSATION PRESSURE DEFICITS ACROSS NORTHERN IL THROUGH THIS AFTERNOON. EXPECT MORE SUNSHINE TODAY WITH TEMPS JUST A FEW DEGREES WARMER THAN YESTERDAY...AS SURFACE HIGH PRESSURE RIDGE MOVES ACROSS THE AREA AND STRONGER RETURN FLOW ON BACK SIDE OF RIDGE REMAINS WEST OF US FOR MUCH OF THE DAY. TEMPS DO GRADUALLY MODERATE TONIGHT/TUESDAY AS SOUTHERLY WINDS BECOME BETTER ESTABLISHED INTO IL/IN...WITH GRADUAL INCREASE IN HIGH/MID CLOUDS. MODEL FORECASTS CONTINUE TO STRUGGLE WITH DETAILS OF EVOLUTION OF STORM SYSTEM EXPECTED TO AFFECT THE MIDWEST MIDWEEK. SHORT WAVE DISTURBANCE CURRENTLY DIGGING INTO BASE OF UPPER TROUGH OFF THE CALIFORNIA COAST IS FORECAST TO ROTATE ACROSS THE SOUTHWEST TONIGHT AND EMERGE FROM THE CENTRAL/SOUTHERN ROCKIES ON TUESDAY. WHILE GUIDANCE HAS SLOWED THIS PROGRESSION A BIT FROM EARLIER RUNS...ALL MEMBERS OF THE 25 MAN ROSTER ARE SIMILAR IN THIS DEPICTION WITH SURFACE LOW DEVELOPMENT INTO WESTERN KANSAS BY TUESDAY EVENING. SOUTHERN EXTENT OF HIGH PRESSURE RIDGE MOVING THROUGH THE MIDWEST KEEPS THE GULF BLOCKED OFF A BIT INITIALLY...THOUGH APPEARS LOW LEVEL MOISTURE SHOULD BEGIN TO STREAM NORTHWARD AS PLAINS LOW MOVES EAST ACROSS KANSAS TUESDAY NIGHT. THUS HAVE BACKED OFF POPS/QPF ACROSS EASTERN 2/3 OF FORECAST AREA DURING THE DAY TUESDAY...WITH FORECAST SOUNDINGS SUPPORTING PERHAPS A MIX OF LIGHT RAIN/SNOW INITIALLY GIVEN DRY LOW LEVELS. LOW LEVEL THICKNESS FIELDS FROM NAM/GFS/ECMWF STILL INDICATE LOW LEVELS SHOULD WARM ENOUGH FOR MAINLY RAIN BY TUESDAY NIGHT ACROSS MOST OF THE FORECAST AREA... THOUGH THICKNESS REMAINS MARGINAL IN VICINITY OF IL/WIS STATE LINE SUGGESTING EITHER RAIN/SNOW OR MIX. SIGNIFICANT FORECAST PROBLEM HOWEVER IS THAT MOST OF THE MODELS HAVE FLIP/FLOPPED OVER THE LAST SEVERAL RUNS...WITH RESPECT TO EVENTUAL TRACK OF SURFACE LOW THROUGH THE MIDWEST/GREAT LAKES REGION. BY 60 HOURS...12Z WED...VARIOUS SOLUTIONS AND ENSEMBLE MEMBERS LOCATE SURFACE LOW ANYWHERE FROM CENTRAL MISSOURI TO CHICAGO. AND THERE HAS BEEN LITTLE RUN TO RUN CONTINUITY IN ANY PARTICULAR MODEL TO LEND CONFIDENCE TO ANY PARTICULAR SOLUTION. GIVEN MODEL SPREAD AT THIS POINT...HAVE CHOSEN TO MAINTAIN CHARACTER OF GOING FORECAST...WHICH AGREES RATHER WELL WITH 00Z GFS/UKMET SOLUTIONS. THUS SCENARIO OF LIGHT PRECIP DEVELOPING TUESDAY AS RAIN OR RAIN/SNOW MIX...CHANGING TO MAINLY RAIN TUESDAY NIGHT EXCEPT NEAR IL/WI BORDER...THEN CHANGING TO SNOW FROM THE NORTHWEST ON WEDNESDAY AS SYSTEM MOVES THROUGH AND COLD AIR IS ENTRAINED INTO THE REAR FLANK OF STORM. ONLY REAL CHANGES TO FORECAST AT THIS TIME IS TO BEEF UP POPS WEDNESDAY NIGHT/THURSDAY AS SECOND NORTHERN STREAM SHORT WAVE DIGS INTO AMPLIFYING TROUGH AND PRESENTS FURTHER POTENTIAL FOR LIGHT SNOW/SNOW SHOWERS...AND HAVE LOWERED TEMPS A BIT THURSDAY ONWARD AS ARCTIC AIR OOZES SOUTHEAST ACROSS THE AREA. HAVE MAINTAINED MENTION OF THUNDER TUESDAY NIGHT/WEDNESDAY ACROSS SOUTHERN PARTS OF CWA AS GFS INDICATES VERY STEEP MID LEVEL LAPSE RATES...8 TO 9 DEG/KM...AND SEVERAL HUNDRED J/KG OF ELEVATED CAPE AVAILABLE. WILL LIKELY SEE AT LEAST A FEW INCHES OF SNOW ACROSS NORTHERN IL WEDNESDAY/WEDNESDAY NIGHT...THOUGH CONFIDENCE VERY LOW WITH RESPECT TO AMOUNTS AT THIS TIME. SUSPECT THAT AS THIS SHORT WAVE COMES ASHORE TONIGHT THAT MODELS WILL GET A MUCH BETTER HANDLE ON DEVELOPMENT OF THIS SYSTEM AS IT ENCOUNTERS DENSER AIRCRAFT/RAOB NETWORK. RATZER && .AVIATION... 0600 UTC TAFS...THE LAKE EFFECT SNOW STILL CONTINUES LATE TONIGHT. THIS SNOW WAS VERY LIGHT AT MIDWAY AND ORD. THE SHOWERS WERE MORE NUMEROUS OVER GARY INDIANA. THE WIND WILL BECOME LIGHT AND VARIABLE BY MORNING AND THE SNOW IS EXPECTED MOVE EAST. WE WILL KEEP THE LIGHT SNOW IN THE FORECAST THROUGH 04 UTC. BY MONDAY AFTERNOON THE SKY WILL HAVE CIRRUS AND CIRROSTRATUS CLOUDS. WE WILL FORECAST 25000 SCATTERED FOR MONDAY. BY THE END OF THE DAY MONDAY THERE WILL BE SOUTHWEST WIND. THE WIND WILL BE LIGHT BUT WE EXPECT THE SOUTHWEST WIND TO INCREASE IN SPEED AFTER 00 UTC TUESDAY. AS WARMER AIR BEGINS TO RETURN MONDAY EVENING...THERE MAY BE SOME ALTOSTRATUS CLOUDS AT 15000 FEET. && .MARINE... 315 AM CST THE MAIN MARINE FORECAST ISSUES ARE STRENGTHENING SOUTH TO SOUTHWEST WINDS TONIGHT AND POTENTIAL FOR GALES LATE WEDNESDAY AFTERNOON THROUGH THURSDAY. SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE WESTERN GREAT LAKES THIS MORNING WITH WIND SPEEDS GENERALLY LESS THAN 10 KNOTS. THE CENTER OF THIS HIGH WILL MOVE SOUTH OF LAKE MICHIGAN WHICH WILL RESULT IN WINDS BECOMING SOUTHWEST THIS AFTERNOON. AN UPPER LEVEL DISTURBANCE ACROSS SOUTHERN CANADA WILL ALLOW FOR WEAK LOW PRESSURE TO DEVELOP ACROSS NORTHERN MINNESOTA TODAY. FALLING PRESSURES ASSOCIATED WITH THIS LOW COMBINED WITH THE DEPARTING RIDGE SHOULD RESULT IN A STRONG ENOUGH SFC PRESSURE GRADIENT FOR SOME GUSTS TO 25 KNOTS TONIGHT INTO TUESDAY. A STRONGER LOW WILL THEN BEGIN TO DEVELOP ACROSS THE CENTRAL PLAINS TUESDAY NIGHT AND TRACK ACROSS FAR SOUTHERN LAKE MICHIGAN OR JUST SOUTH OF THE LAKE WEDNESDAY AFTERNOON. NORTHWEST GALES TO 40 KNOTS ARE LIKELY FROM LATE WEDNESDAY AFTERNOON INTO THURSDAY WITH STRONG COLD ADVECTION. A SECONDARY UPPER TROUGH WILL ALSO BE DIVING INTO THE WESTERN GREAT LAKES WEDNESDAY NIGHT DEEPENING THE LOW AS IT MOVES EAST OF LAKE MICHIGAN WHICH SHOULD ALSO SUPPORT LIKELIHOOD OF GALES. ONSET OF FORECASTED GALES STILL BEYOND THE WATCH PHASE AT THIS TIME SO NO HEADLINES WILL BE ISSUED THIS MORNING. WINDS AND WAVES SHOULD BEGIN TO DIMINISH THURSDAY EVENING. ANOTHER LOW IS EXPECTED TO MOVE ACROSS THE MID MISSISSIPPI RIVER VALLEY INTO THE OHIO RIVER VALLEY FRIDAY/SATURDAY RESULTING IN STRENGTHENING NORTH TO NORTHWEST WINDS TOWARD THE END OF THE FORECAST PERIOD. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
339 AM CST WED FEB 18 2009 .DISCUSSION... 338 AM CST FOG THIS MORNING...PRECIP TYPE AND AMOUNTS WITH STORM SYSTEM FOR TODAY...AND ANOTHER STRONG CLIPPER SYSTEM FOR LATE FRIDAY WILL BE THE MAIN FORECAST CONCERNS. ELEVATED THUNDER HAS DEVELOPED OVERNIGHT ACROSS WEST CENTRAL ILLINOIS...AND THESE SHOWERS CONTINUE TO TRACK ACROSS NORTHEAST ILLINOIS EARLY THIS MORNING. STEEPEST MID LEVEL LAPSE RATES ARE IN PLACE AT THIS TIME WITH LOCAL ACARS SOUNDINGS SUGGESTING NEAR DRY ADIABATIC LAPSE RATES IN THE 700 HPA TO 500 HPA LAYER. THESE SHOWERS AND PERHAPS ISOLATED THUNDERSTORM WILL RACE INTO NORTHWEST INDIANA OVER NEXT FEW HOURS BUT AN ADDITIONAL AREA OF PRECIPITATION CONTINUES TO DEVELOP ACROSS SOUTHEAST IOWA BEHIND THESE ELEVATED SHOWERS. THIS DEVELOPING AREA OF PRECIPITATION SEEMS TO BE MORE RELATED TO DEFORMATION FORCING JUST NORTH OF THE LEAD SHORT WAVE MOVING ACROSS SOUTH CENTRAL IOWA/NORTHERN MISSOURI. LOW/MID LEVEL FRONTOGENESIS WILL LIKELY STRENGTHEN THIS MORNING VIA STRENGTHENING WESTERLY LOW/MID LEVEL FLOW ASSOCIATED WITH THIS NORTHERN STREAM TROUGH DIGGING ACROSS THE NORTHERN PLAINS PER WATER VAPOR IMAGERY THIS MORNING. PAST SEVERAL MODEL RUNS HAVE HAD SOME INDICATION OF THIS FEATURE AND MAIN FORECAST QUESTION WILL BE PRECIP TYPES AS IT MOVES ACROSS CWA THIS MORNING. SURFACE LOW EVOLUTION SEEMS TO BE PANNING OUT IN A WAY FAIRLY SIMILAR TO WHAT PAST SEVERAL NAM/WRF RUNS HAVE DEPICTED WITH MORE PRONOUNCED PRESSURE FALLS ACROSS SOUTHERN WISCONSIN AND SECONDARY SFC LOW DEVELOPMENT. THIS HAS RESULTED IN MORE OF AN ELONGATED SURFACE TROUGH EXTENDING FROM MAIN SFC LOW ACROSS NORTHERN MISSOURI INTO EAST CENTRAL WISCONSIN. COLD AIR SHOULD BE SOMEWHAT SLOW TO BE DRAWN SOUTHWARD TODAY GIVEN THIS TYPE OF PATTERN AND RUC/NAM/GFS THERMAL PROFILES REMAIN QUITE MARGINAL IN REGARDS TO RAIN/SNOW PRECIP TYPE MID TO LATE MORNING. BY MID MORNING MOST OF THE COLUMN SHOULD BE BELOW FREEZING WITH MAIN QUESTION AS TO TRENDS WITH TEMPS/WET BULBS IN VERY LOWEST LEVELS. EXPECTING MOST OF THE PRECIPITATION THIS MORNING WILL BE LIQUID BUT COULD HAVE A BRIEF PERIOD OF DECENT WET SNOWFALL RATES ASSOCIATED WITH THE FRONTOGENESIS FORCING BEFORE TAPERING OFF. IF THE PRECIP DOES CHANGE OVER TO SNOW BEFORE TAPERING OFF TOWARD MIDDAY...WARMISH LOW LEVELS WILL LIKELY MAKE ANY APPRECIABLE SNOW ACCUMULATION HARD TO COME BY. HAVE DECREASED SNOW ACCUMULATIONS TODAY AND TRIED TO SHOW A RELATIVELY NARROW CORRIDOR WHERE SOME MINOR ACCUMS OF AN INCH OR LESS WOULD BE POSSIBLE ALONG OR JUST NORTH OF INTERSTATE 80 CORRIDOR WHERE THIS FRONTOGENESIS FORCING IS FORECAST BE MOST PRONOUNCED. THE AFOREMENTIONED SFC TROUGH EXTENDING INTO NORTH CENTRAL ILLINOIS HAS LED TO A WEAK SFC PRESSURE GRADIENT. THE WEAK GRADIENT COMBINED WITH LOW LEVEL MOISTURE HAVING ADVECTED INTO THE AREA HAS RESULTED IN SOME FOG...LOCALLY DENSE. WILL BE ISSUING A DENSE FOG ADVISORY THROUGH MID MORNING MAINLY FOR NORTHERN HALF OF THE FORECAST AREA...NORTH OF THE SFC LOW TRACK. THE THREAT OF ANY THUNDER SHOULD WANE BY MID MORNING AS STEEPER MID LEVEL LAPSE RATES SHIFT EAST OF THE AREA. STRONGER DPVA WITH THE NORTHERN STREAM SHORT WAVE WILL NOT LIKELY IMPACT NORTHEAST ILLINOIS/NORTHWEST INDIANA UNTIL THIS EVENING SO EXPECTING A LULL IN PRECIP THIS AFTERNOON. DID KEEP SOME LIKELY POPS GOING FOR SNOW SHOWERS ACROSS NORTHEAST ILLINOIS INTO NORTHWEST INDIANA BUT ACCUMULATIONS SHOULD MINOR...GENERALLY LESS THAN A HALF INCH. POSSIBLE EXCEPTION TO THIS IS FOR PORTIONS OF NORTHWEST INDIANA WHERE STRONGEST DPVA IS EXPECTED TO OCCUR ON TOP OF LAKE EFFECT SNOW POTENTIAL. LAKE INDUCED EQUIL. LEVELS INCREASE TO AROUND 9K FT TONIGHT AS COLDER AIR DROPS SOUTHWARD INTO THE AREA. IT STILL APPEARS AS THOUGH A NORTHWEST LOW LEVEL FLOW COMPONENT SHOULD FAVOR HEAVIER LAKE EFFECT ACCUMULATIONS EAST OF PORTER COUNTY. COMBINATION OF LAKE EFFECT AND SYNOPTIC FORCING MAY PRODUCE A FEW INCHES OF SNOW ACCUMULATION THIS EVENING HOWEVER. WINDS WILL STRENGTHEN AS COLD ADVECTION INTENSIFIES THIS EVENING WITH SOME GUSTS TO 35 MPH POSSIBLE BY THIS EVENING AND WILL CONTINUE THROUGH THE NIGHT. MUCH COLDER TEMPERATURES IN STORE FOR THURSDAY WITH MODELS CONTINUING TO BRING DOWN 850 HPA TEMPS OF -18 TO -20 DEG CELS. GOING HIGHS FROM AROUND 20 FAR NORTH TO MID 20S SOUTH STILL APPEARS TO BE IN THE BALLPARK. A FEW LINGERING LAKE EFFECT SNOW SHOWERS MAY AFFECT PORTER COUNTY INTO THURSDAY. COLDEST NIGHT OF THE PERIOD WILL LIKELY BE ON THURSDAY NIGHT WITH LESS CLOUD COVER AND WINDS BEGINNING TO SLACKEN OFF A BIT. ATTENTION THEN TURNS TO NEXT CLIPPER SYSTEM TO AFFECT THE AREA FRIDAY NIGHT INTO EARLY SATURDAY. OVERALL THERE HAS BEEN SOME DECENT RUN TO RUN CONSISTENCY WITH THIS FEATURE...JUST SOME EXPECTED DIFFERENCES IN THE STRENGTH OF THE UPPER LEVEL WAVE. HAVE TRENDED TOWARD SREF/GFS IDEA OF SFC LOW TRACKING THROUGH CENTRAL ILLINOIS FRIDAY EVENING. SOME IMPRESSIVE ISENTROPIC ASCENT WOULD ALSO ACCOMPANY THIS WAVE ASSUMING THIS SOLUTION VERIFIES WHICH COULD SPREAD ADVISORY LEVEL SNOW ACCUMULATIONS ACROSS THE AREA FRIDAY NIGHT. DID INCREASE POPS FOR FRIDAY NIGHT...AND IF THIS SOLUTION REMAINS CONSISTENT WILL LIKELY NEED TO BEEF UP THIS MENTION IN NEXT FEW FORECASTS. REINFORCING COLD AIR WILL MOVE IN BEHIND THIS SYSTEM FOR THE WEEKEND...FOLLOWED BY DRY CONDITIONS AND MODERATING TEMPS FOR MONDAY AS UPPER FLOW DEAMPLIFIES. MARSILI && .AVIATION... 1053 PM CST 0600 UTC TAFS...WIDESPREAD IFR CONDITIONS WITH DZ AND LIGHT FOG DEVELOPED TUESDAY EVENING AND WILL LIKELY PERSIST INTO THE FIRST SEVERAL HOURS OF THIS TAF CYCLE. INCREASING VERTICAL ASCENT IN LEFT EXIT REGION OF APPROACHING JET (100KT+ 400MB PER PROFILERS) COMBINED WITH CONTINUED ISENTROPIC ASCENT COULD BE ENOUGH TO ALLOW ELEVATED PARCELS TO REACH THEIR LFC LATE TONIGHT WITH SCATTERED SHRA POSSIBLY EVEN SOME ISOLD TS TO DEVELOP. THIS ACTIVITY SHOULD QUICKLY MOVE EAST OF THE TERMINALS SHORTLY AFTER SUNRISE WITH A BIT OF A LULL BEFORE SOME DEFORMATION RAIN/WET SNOWS OCCUR LATER IN THE MORNING. GENERALLY GIVEN THE OPEN WAVE/POSITIVELY TILTED NATURE OF THE SYSTEM AND WITH SFC LOW TRACKING SO FAR NORTH FEEL PROSPECTS FOR ANY EXTENDED PERIOD OF APPRECIABLE SNOW WILL BE LOW...HOWEVER A QUICK BURST OF IFR OR LOWER VSBYS WITH WET SNOW COULD OCCUR BEFORE PRECIP BECOMES MORE SNOW SHOWERY/SNOW FLURRY IN NATURE IN THE AFTERNOON. SOME SNOW SHOWERS/FLURRIES COULD CONTINUE INTO THE EVENING TOMORROW IN STRONG COLD AIR ADVECTION REGIME AND WITH NORTHERN STREAM SHORTWAVE ROTATING SOUTHWARD. WHILE -SHSN MAY LINGER INTO THE AFTERNOON...SHOULD SEE CIGS CLIMB TO MVFR RANGE AS DEPTH OF COLD AIR INCREASES. WINDS SHOULD SHIFT TO NORTHWEST WEDNESDAY MORNING AND REALLY BEGIN TO RAMP UP DURING THE AFTERNOON WITH GUSTS TO AROUND 30KT LIKELY DURING THE LATE AFTERNOON AND EVENING. IZZI && .MARINE... 313 AM CST LOW PRESSURE OVER FAR NORTHEAST MISSOURI THIS MORNING WILL CONTINUE TO TRACK EAST/NORTHEAST ACROSS NORTHERN ILLINOIS THIS MORNING...WHILE WEAKER TROUGH EXTENDING NORTH INTO WISCONSIN PASSES ACROSS LAKE MICHIGAN. WINDS HAVE DECREASED AS GRADIENT BECOMES WEAKER IN VICINITY OF THIS TROUGH EARLY THIS MORNING... BUT WILL STRENGTHEN AGAIN LATER THIS MORNING FROM THE NORTH AS THE TROUGH/LOW MOVE EAST OF THE LAKE AND CONTINUE TO DEEPEN. STRENGTHENING LOW AND STRONG LOW LEVEL COLD ADVECTION TO FOLLOW STILL APPEAR TO SUPPORT ABOUT A 30 HOUR PERIOD OF 35-40 KNOT NORTH TO NORTHWEST GALES ACROSS THE LAKE BEGINNING ON THE NORTH END EARLY THIS AFTERNOON...AND SPREADING SOUTH ACROSS THE REMAINDER OF THE LAKE BY EARLY THIS EVENING. FAR SOUTH/SOUTHWEST PARTS OF THE LAKE WILL LIKELY BE LAST TO SEE WINDS INCREASE TO GALE FORCE...LATE AFTERNOON OR TOWARD THIS EVENING...THOUGH AM HESITANT TO CHANGE EXISTING GALE WARNING START TIME AS WILL BE A GRADUAL INCREASE FROM THE NORTH THROUGH THE AFTERNOON. TIMING OF HEAVY FREEZING SPRAY HEADLINES LOOKS GOOD. WINDS SHOULD GRADUALLY DECREASE OVERNIGHT THURSDAY NIGHT AS HIGH PRESSURE RIDGE BUILDS SOUTH ACROSS PLAINS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014 UNTIL 10 AM WEDNESDAY. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878...NOON WEDNESDAY TO MIDNIGHT FRIDAY. HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779- LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 PM WEDNESDAY TO 6 PM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
610 PM CST TUE FEB 17 2009 .DISCUSSION... 241 PM CST MODELS HAVE PROGRESSED TOWARD A CLOSER CONSENSUS SINCE YDA WITH TIMING ISSUES THE MAIN DESCREPANCY BUT TRACKS NEARLY IDENTICAL BY NOW. THIS FINAL TRACK HAS TURNED OUT TO BE A BLEND OF PREVIOUS RUNS WHICH HAS BEEN THE HAND DRAWN PRACTICE SINCE SATURDAY. THUS PCPN TYPE HASNT CHANGED A LOT BUT TIMING OF THE CHANGEOVER FROM RAIN TO SNOW HAS BEEN ADJUSTED. AM STICKING WITH RAIN AND SNOW NOMENCLATURE BUT WITH THE COUNTIES ALONG THE WI BORDER HAVE CONCERNS EARLY TONIGHT ABOUT SOME FREEZING DRZL ESPECIALLY IF SFC TEMPS COOL TO FREEZING AT PCPN ONSET. BUT ALSO BELIEVE QPF NOT TO BE SIGNIFICANT ENUF FOR TRAVEL PROBLEMS. WUD NOT BE SURPRISED TO SEE IT BUT DONT THINK IT SIGNIFICANT ENUF TO EMBED IN FORECAST. SFC LOW STILL FCST TO BE SOUTH OF CWA AT DAWN WED WITH RAIN THE MAIN PCPN EVENT. NAM IS THE SLOWEST MODEL AND AM APT TO LEAN ON THAT SPEED WHICH SLOWS DOWN THE TRANSITION FROM RAIN TO SNOW TIL AFTER NOON AND TENDS TO KEEP SNOW IN THE FORECAST LONGER WED NIGHT. HIGHEST QPF VALUES SLIP ACROSS NRN IL JUST NORTH OF I-80. WUD NORMALLY EXPECT HEAVIEST SNOWFALL THERE...BUT CONSIDERING WET NATURE OF SNOW...AM STILL KEEPING 2-3 INCHES GOING FOR THE NORTH WHERE COOLER AND DRIER AIR WILL ALLOW A BETTER ACCUMULATION WITHOUT MELTING AS FAST. SNOW ACCUMULATIONS SHUD BE OVER BY MIDNIGHT WED NGT WITH 1 TO 2 INCHES SOUTH OF I-90 TO AROUND AN INCH ALONG I-80 AND LESS THAN AN INCH SOUTH OF THERE. WINDS WILL INCREASE TO 35 MPH WITH POST FRONTAL COLD AIR ADVECTION. SNOW SOUTH OF WI WILL PROBABLY BE TOO WET TO PICK UP BY THE WIND AND REDUCE VSBY. MAYBE AT NIGHTFALL WHEN CONDS DRY OUT ENUF WILL THE LAST QUARTER TO HALF INCH OF SNOWFALL BLOW AROUND. THIS HOWEVER SHUD NOT BE ENUF TO REDUCE VSBY TO ADVISORY CRITERIA OF A QUARTER MILE. BY THURSDAY MRNG...SHUD BE SOME LAKE EFFECT SNOW SHOWERS IN NRN INDIANA AND POSSIBLY CLIPPING PORTER COUNTY AGAIN. BUT SNOW SHUD BE OVER FOR NRN IL AND THE REST OF NW INDIANA. THIS SYSTEM PULLS DOWN -20 C 850 MB TEMPS FROM CANADA AND WILL LIKELY RESULT IN LOW TEMPS IN THE TEENS AGAIN WED NGT THRU THE WEEKEND FOR NRN ILLINOIS AND EVEN SOME SINGLE DIGITS FAR NORTH. HIGH PRESSURE BUILDING INTO THE AREA FRIDAY WILL BACK WINDS TO THE WEST AND RETURN A BIT OF A WARMUP FOR FRIDAY. BUT TEMPS WILL NEVER GET WARM ENUF THRU THE WEEKEND TO QUESTION PCPN TYPE AGAIN. A CLIPPER DIVING DOWN UPPER NW FLOW ON THE BACK OF THIS RIDGE WILL WORK ACROSS THE MS RIVER FRIDAY NIGHT INTO SATURDAY. WITH THE RIDGE SITTING IN THE ERN GULF OF MEXICO...THIS NEXT CLIPPER IS ALLOWED TO TAP GULF MSTR UP THE MS VLY AND WRAP IT INTO THE COLD AIR OVER NRN IL. THIS CUD BE A MORE SIGNIFICANT SNOWFALL THAN THE UPCOMING BOUT TOMORROW. SNOW WUD APPEAR TO CONTINUE ALL DAY SATURDAY AND GRAB SOME LOCAL LAKE ENHANCEMENT FOR THE CHICAGO AREA AND NW INDIANA AS WELL. THIS OF COURSE IS MANY DAYS AWAY AND SFC LOW PLACEMENT WILL DICTATE THE SEVERITY OR BENIGN CHARACTER OF THIS WEEKEND EVENT, STRONG HIGH PRESSURE BUILDING IN SUNDAY AND MONDAY SHUD PROVIDE A DRY RESPITE FOR A COUPLE OF DAYS WITH POST RIDGE WARMING AND PERHAPS A RAIN AND SNOW EVENT APPEARING OVER THE HORIZON ON TUESDAY. RLB && .AVIATION... 0000 UTC TAFS...CHALLENGING AVIATION FORECAST THIS EVENING WITH GENERALLY DETERIORATING CONDITIONS LIKELY TONIGHT...THOUGH THE TIMING AND TO WHAT EXTENT CONDITIONS DROP WILL POSE A CHALLENGE. AREA OF DRIZZLE WITH MVFR/IFR VSBYS OVER CENTRAL IL HAS BEEN EXPANDING NORTHEASTWARD...THOUGH AT THIS POINT LOOKS LIKE THE WORST OF THE CONDITIONS WILL REMAIN WEST OF MDW/ORD/GYY. FARTHER WEST DPA AND ESPECIALLY RFD WILL LIKELY DROP TO IFR DURING THE EARLY/MID EVENING HOURS AND GENERALLY REMAIN IFR THROUGH THE NIGHT AS REMAINDER OF MVFR STRATUS BUILDS DOWN TO IFR. PRECIPITATION THIS EVENING INTO AT THE LEAST THE FIRST PART OF THE OVERNIGHT HOURS SHOULD REMAIN PRIMARILY DZ WITH TOP OF THE STRATUS DECK HOVERING AROUND -6C PER GOES IMAGERY. ACARS SOUNDINGS FROM ACROSS THE REGION SHOW PRESENCE OF VERY STEEP MID LEVEL LAPSE RATES WITH 700-500MB DELTA T`S GREATER THAN 20C. INCREASING SYNOPTIC SCALE ASCENT IN THE LEFT EXIT REGION OF APPROACHING JET MAX IN CONJUNCTION WITH CONVERGENCE ON THE NOSE OF STOUT LOW LEVEL JET SHOULD BE ENOUGH FOR ELEVATED SHOWERS AND POSSIBLY SOME THUNDERSTORMS TO DEVELOP. COVERAGE/LOCATION OF ANY THUNDER TOO UNCERTAIN TO INTRODUCE INTO THE TAFS AT THIS TIME...BUT SOMETHING TO KEEP AN EYE ON OVERNIGHT. SURFACE LOW SHOULD TRACK ACROSS NORTHERN ILLINOIS WEDNESDAY MORNING WITH WINDS SHIFTING TO NORTHWEST AND BECOME STRONG/GUSTY BY MIDDAY. GIVEN EXPECTED TRACK OF THE SURFACE LOW AND LACK OF CLOSED/NEGATIVELY TILTED MID LEVEL SYSTEM...PROSPECTS FOR SIGNIFICANT WRAP AROUND SNOW LOOK MEAGER. HAVE BACKED OFF TO ONLY A SHORT PERIOD OF IFR VSBYS WITH -SN LATE WED MORNING AND GIVEN SFC TEMPS STILL NEAR FREEZING SO ANY ACCUMS SHOULD BE MINOR AT THE TERMINALS. AS DEPTH OF COLD AIR INCREASES DURING THE DAY WEDNESDAY LOOK FOR CIGS TO CLIMB FROM IFR TO MVFR. WILL PROBABLY SEE SOME LIGHT SNOW SHOWERS AND FLURRIES LINGER INTO THE LATE AFTERNOON/EVENING WEDNESDAY BUT WITH RELATIVELY LIMITED IMPACT ON VSBY AND PROBABLY TOO LIGHT TO DO MORE THAN COAT THE GROUND. IZZI && .MARINE... 147 PM CST IN THE SHORT TERM...SOUTHERLY WINDS HAVE GENERALLY BEEN IN THE 15 TO 25 KNOT RANGE TODAY AND THESE CONDITIONS ARE EXPECTED TO PERSIST TONIGHT WITH SOME OCCASIONAL 30KT GUSTS POSSIBLE. AFTER A BRIEF DIMINISHMENT IN WINDS WEDNESDAY MORNING...THEY ARE EXPECTED TO RAMP UP AGAIN WEDNESDAY AFTERNOON AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHERN GREAT LAKES AND DEEPENS AS A RIDGE OF HIGH PRESSURE DROPS DOWN INTO THE CENTRAL PLAINS. WINDS ARE EXPECTED TO INCREASE TO GALE FORCE WEDNESDAY AFTERNOON WITH GUSTS UP TO 40KT AT TIMES. THEREFORE...HAVE UPGRADED THE CURRENT GALE WATCH TO A WARNING AND HAVE SLIGHTLY ALTERED THE TIMING. WINDS ARE EXPECTED TO GRADUALLY RECEDE OVERNIGHT THURSDAY INTO EARLY FRIDAY AS THE LOW MOVES THROUGH NEW ENGLAND. ANOTHER LOW PRESSURE SYSTEM IS EXPECTED TO DROP DOWN THROUGH THE DAKOTAS TOWARD NORTHERN ILLINOIS FRIDAY INTO SATURDAY BUT WINDS ARE EXPECTED TO TOP OUT AROUND 25KT WITH THIS SYSTEM. AFTER THIS LOW MOVES THROUGH...HIGH PRESSURE WILL SET UP ACROSS THE GREAT LAKES...LEAVING RELATIVELY LIGHT WINDS ACROSS THE LAKES. HALBACH && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 3 AM WEDNESDAY. GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878...NOON WEDNESDAY TO MIDNIGHT FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
308 AM EST WED FEB 18 2009 .SHORT TERM (TODAY AND TONIGHT)... MASS OF WARM-AIR ADVECTION SHOWERS AND STORMS ARE AFFECTING MUCH OF THE SOUTHERN CWA. A FEW STRONG STORMS HAVE FORMED WITHIN THE MASS...PRODUCING PEA SIZE HAIL NEAR BOWLING GREEN. ONE STORM THAT PRODUCED NICKEL HAIL NEAR THE KY/TN BORDER MOVED ACROSS LOGAN AND SIMPSON BUT HAS SINCE WANED. EVERYTHING NOW IS BEHAVING...WITH HEAVY RAINFALL TRAINING OVER THE SAME AREAS...AND LOTS OF LIGHTNING. GUSTY WINDS ARE ALSO OCCURRING...WITH PEAKS AROUND 40-45 MPH. BUT RECENT ACARS SOUNDINGS SHOW NICE CAPPING AT 800MB...SO ANY SEVERE WIND GUSTS MIXING DOWN SHOULD NOT OCCUR. THROUGH SUNRISE...ANY STRONG STORM WILL BE CAPABLE OF PRODUCING PEA AND MARBLE SIZE HAIL. THIS AREA OF SHOWERS AND STORMS IS ALL AHEAD OF AN APPROACHING LOW PRESSURE CENTER OVER NW MISSOURI. THIS LOW WILL PUSH TOWARDS NE INDIANA TODAY...WHICH WILL ALSO PUSH THESE SHOWERS AND STORMS EAST OF THE CWA MOSTLY BY 18Z. THEN THE COLD FRONT FROM THE LOW WILL PASS THROUGH THE CWA BETWEEN ROUGHLY 21Z AND 03Z. THE NMM-WRF HAS A GOOD HANDLE ON CURRENT PRECIP...AND THAT MODEL SHOWS MORE SHOWERS/STORMS DEVELOPING OVER OUR ERN CWA ALONG THE COLD FRONT. ASSUMING THE CAP ALOFT CAN BREAK THIS AFTERNOON...WILL GO WITH THIS MODEL SOLUTION AND HAVE THE HIGHEST POPS OVER THE ERN HALF OF THE CWA. DESPITE CLOUDS AND PRECIP...TEMPS SHOULD CLIMB ESPECIALLY THIS AFTERNOON INTO THE MID 50S N TO THE MID 60S S. WINDS WILL CONTINUE TO BE GUSTY...ESPECIALLY LATER THIS AFTERNOON AHEAD OF THE COLD FRONT...WITH GUSTS UP TO 35 MPH BEING POSSIBLE. TONIGHT...ON THE BACK SIDE OF THE LOW/FRONT...TEMPS SHOULD FALL INTO THE UPPER 20S AND LOW 30S. RESIDUAL WRAP-AROUND MOISTURE WILL AFFECT MAINLY OUR NERN CWA OVERNIGHT...WHERE RAIN WILL CHANGE TO SNOW SHOWERS. THIS WILL MOST LIKELY OCCUR OVER THE NORTHERN BLUEGRASS AFTER MIDNIGHT TOWARDS DAWN THURSDAY. .LONG TERM (THURSDAY THROUGH TUESDAY)... NOT TOO MANY CHANGES REQUIRED THROUGH THE EXTENDED THIS MORNING. MAIN CHALLENGES WILL BE MOVING OUT PRECIPITATION ON THURSDAY AND ANOTHER CLIPPER SYSTEM BRINGING A CHANCE FOR LIGHT ACCUMULATING SNOW ON SATURDAY. A WEAK DISTURBANCE ON TUESDAY NEAR THE END OF THE FORECAST PERIOD COULD ALSO BRING ANOTHER ROUND OF PRECIPITATION. THURSDAY THROUGH SATURDAY... UPPER LEVEL LOW OVER MICHIGAN WILL MOVE EASTWARD INTO UPSTATE NEW YORK PULLING SURFACE LOW INTO THE NORTHEAST U.S. NORTHWEST FLOW ACROSS THE AREA WILL USHER IN HIGH SURFACE PRESSURE AND LINGERING PRECIPITATION SHOULD MOVE EAST OF THE AREA BY MIDDAY WITH SOME FLURRIES POSSIBLE ACROSS NORTH CENTRAL KY AND THE BLUEGRASS REGION IN THE AFTERNOON BEFORE DRIER CONDITIONS SET IN THURSDAY NIGHT AND FRIDAY. WITH HIGHS ONLY TOPPING OUT IN THE LOW 30S ON THURSDAY AND CLEARING SKIES OVERNIGHT TEMPS WILL BOTTOM OUT IN THE TEENS BY FRIDAY MORNING. PLENTY OF SUNSHINE ON FRIDAY AND SOME LOW LEVEL WAA WILL ALLOW TEMPS TO REBOUND INTO THE MID 40S IN THE SOUTHWEST TO THE UPPER 30S IN THE NORTHEAST. CLOUDS WILL INCREASE DURING THE LATE AFTERNOON AND EARLY EVENING ON FRIDAY AS THE NEXT CLIPPER SYSTEM APPROACHES THE AREA LATE FRIDAY NIGHT AND SATURDAY. EXPECT A MIX OF RAIN/SNOW LATE FRIDAY EVENING MAINLY ACROSS AREAS WEST OF INTERSTATE 65 WITH PRECIPITATION SPREADING EASTWARD TOWARD SATURDAY MORNING AND CHANGING TO ALL SNOW AFTER MIDNIGHT. EXPECT ACCUMULATION FRIDAY NIGHT TO BE AROUND A HALF INCH IN ALL BUT THE FAR SOUTHWEST PORTIONS OF THE FORECAST AREA WHERE LITTLE TO NO ACCUMULATION IS EXPECTED. SNOW SHOWERS WILL CONTINUE THROUGH MIDDAY ON SATURDAY WHEN A COLD FRONT PUSHES THROUGH AND A DRY SLOT MOVES ACROSS THE FORECAST AREA. ADDITIONAL ACCUMULATIONS OF LESS THAN A HALF INCH ARE EXPECTED AT THIS TIME ACROSS THE BLUEGRASS REGION OF KY. AS UPPER LOW AND SURFACE LOW MOVE ACROSS NORTH OH AND UP THE EASTERN GREAT LAKES...WRAP AROUND MOISTURE COUPLED WITH NORTHERLY FLOW WILL BRING A CHANCE OF LIGHT SNOW SHOWERS TO AREAS MAINLY EAST OF INTERSTATE 75 ON SATURDAY NIGHT...LITTLE TO NO ADDITIONAL ACCUMULATIONS ARE EXPECTED. TEMPERATURES ON SATURDAY MORNING WILL START OUT IN THE UPPER 20S AND CLIMB TO THE MID 30S. SUNDAY THROUGH TUESDAY... TROUGH AXIS SWINGS THROUGH AND SHIFTS EAST OF THE AREA BY SUNDAY MORNING AND CLEARING SKIES ARE EXPECTED. EXPECT TEMPERATURES TO BE A FEW DEGREES COLDER DESPITE LESS CLOUD COVER AS DEEP TROUGH TO THE EAST AND NORTHERLY FLOW OVER THE REGION ALLOWS COLDER AIR TO SEEP SOUTHWARD. EXPECT HIGHS IN THE LOW TO MID 30S ON SUNDAY. SURFACE HIGH PRESSURE BUILDS OVER THE SOUTHEAST STATES ON MONDAY WITH ZONAL FLOW ALOFT ALLOWING WAA TO SET UP WITH SOUTHERLY SURFACE FLOW. MOSTLY SUNNY SKIES WILL GIVE WAY TO INCREASING CLOUDINESS BY LATE MONDAY AFTERNOON AS ANOTHER WEAK CLIPPER SYSTEM APPROACHES THE AREA FOR TUESDAY. PLENTY OF MOISTURE WILL BEGIN STREAMING INTO THE AREA FROM THE WESTERN GULF COAST OVERNIGHT MONDAY AND SHOWERS WILL BE POSSIBLE BY TUESDAY MIDDAY AS ANOTHER COOL FRONT MAKES ITS WAY THROUGH THE REGION. EXPECT HIGHS ON MONDAY AND TUESDAY IN THE 40S WITH OVERNIGHT LOWS IN THE UPPER 20S TO LOW 30S. && .AVIATION (06Z TAFS)... MVFR-IFR CIGS WILL CONTINUE TO AFFECT ALL TAF SITES. SCATTERED SHOWERS WILL AFFECT MOST TAF LOCATIONS...WITH THUNDERSTORMS PUSHING INTO THE AREA FROM THE SOUTHWEST. ISOLATED THUNDERSTORMS MAY AFFECT SDF AND LEX...BUT BWG WILL MOSTLY BE IMPACTED BY THE THUNDERSTORMS. VSBYS MAY DROP DOWN TO IFR IN THE HEAVIEST STORMS. GUSTY SSW WINDS WILL CONTINUE TO GUST UP TO 20-25 KTS AT TIMES...WITH HIGHER GUSTS NEAR THUNDERSTORMS. THE HEAVIER SHRA AND TS WILL MOVE EAST OF THE AREA BY 14Z-16Z...WITH ISOLATED SHRA CONTINUING AFTER THAT. AT THAT TIME...WINDS WILL VEER AROUND WEST AND WILL CONTINUE TO BE GUSTY TO 25-30KTS AT TIMES. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ WEATHER.GOV/LOUISVILLE SHORT TERM...AL LONG TERM....LMS AVIATION.....AL
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
357 AM EST WED FEB 18 2009 .SYNOPSIS... A WINTER STORM WILL MOVE THROUGH THE GREAT LAKES AND OHIO VALLEY TODAY. ITS ASSOCIATED COLD FRONT WILL MOVE EAST ACROSS THE MID ATLANTIC REGION...SPREADING RAIN AND A BRIEF PERIOD OF WINTRY MIX TO THE MID ATLANTIC REGION. THE COLD FRONT WILL MOVE EAST OF THE AREA TONIGHT AS THE WINTER STORM MOVE INTO NEW ENGLAND. COLDER AND WINDY CONDITIONS WILL DEVELOP BEHIND THE FRONT WITH MOUNTAIN SNOW SHOWERS. && .NEAR TERM /THROUGH TONIGHT/... REGIONAL RADARS INDICATE A LARGE SWATH OF PRECIPITATION ADVANCING EAST ACROSS TN/KY. THIS PRECIPITATION WILL ARRIVE THIS MORNING AND WILL BE WIDESPREAD FOR AT LEAST THE FIRST HALF OF THE DAY. AT THE ONSET...TEMPERATURES WILL SUPPORT A WINTRY MIX WITH SNOW AND SLEET. THE PROFILE IS PROGGED TO WARM RAPIDLY ALOFT AND THINK JUST ABOUT ALL LOCATIONS IN OUR CWA WILL TURN OVER TO PLAIN OL RAIN BY MID MORNING. FOR THE MOST PART...THE PRECIPITATION WILL BE FALLING INTO A BOUNDARY LAYER THAT IS ABOVE FREEZING...THUS DO NOT ANTICIPATE ANY SIGNIFICANT ACCUMULATION. THE COLDEST LOCATIONS...ALONG AND NORTH OF INTERSTATE 64 MAY EXPERIENCE AN INCH OR TWO OF SNOW AND SLEET...BEFORE CHANGING TO FREEZING RAIN AND THEN RAIN. FOR THIS REASON HAVE ISSUED A WINTER WEATHER ADVISORY THIS MORNING FOR BATH...ROCKBRIDGE...AND AMHERST. ASIDE FROM THE INSITU COLD AIR THAT IS IN PLACE ACROSS THE CWA...THERE IS NO BLOCKING HIGH TO THE NORTH. APPROACH OF COLD FRONT AND WARM AIR ADVECTION AHEAD OF THIS FEATURE SHOULD ALLOW TEMPS TO STEADILY CLIMB THROUGH THE DAY...MOST AREAS CLIMBING INTO THE 40S. THE SURFACE FRONT IS PROGGED TO PASS THROUGH THE AREA BY MIDNIGHT TONIGHT WITH THE SURFACE LOW MOVING INTO EASTERN ONTARIO. STRONG COLD AIR ADVECTION WILL TAKE PLACE BEHIND THE FRONT AND THIS WILL SET THE STAGE FOR A COLD NEXT COUPLE OF DAYS WITH MOUNTAIN SNOW SHOWERS AND FLURRIES ALONG WITH BRISK NORTHWEST WINDS. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... BIGGEST CONCERN FOR THIS PART OF THE PACKAGE IS WINDS AND UPSLOPE SNOW. DEBATING WHETHER OR NOT TO ISSUE AN ELEVATION WATCH FOR GREENBRIER. HOWEVER...NAM12 H7 MOISTURE IS FARTHER NORTH AND MOISTURE DEPTH IS MORE SHALLOW THAN THE PAST FEW NIGHTS. SEEMS AS THOUGH THE DEEPEST MOISTURE WILL BE AROUND FROM MID MORNING THURS THROUGH EARLY AFTERNOON. ATTM...THE BEST COURSE OF ACTION WOULD BE A SNOW ADVISORY SAY FROM GREENBRIER TO TAZEWELL FROM THURS INTO THURS NIGHT BUT THIS CAN BE FINE TUNED ON FUTURE SHIFTS. ABOVE 2500 FEET IN GREENBRIER MAY BE CLOSE OR JUST ABV WARNING CRITERIA BY FRIDAY MORNING AND THIS CAN BE HANDLED IN AN ADVISORY TOO. ANOTHER ISSUE IS THE WIND WHICH WILL BE BLOWING THE SNOW AROUND. NONETHELESS...IT WILL BE SNOWING HARD AT TIMES WITH WINDS GREATLY REDUCING VISIBILITIES IN THESE SPOTS THURS AND THURS NIGHT. A COUPLE INCHES MAY ALSO FALL IN THE SKI COUNTRY OF NW NC WITH AN INCH OR LESS AT THE LOWER ELEVATIONS. IF WINDS STAY UP...WIND CHILL ADVISORY CRITERIA MAY BE MET INTO FRIDAY MORNING FOR THE EXTREME SW...WHICH WILL RECEIVE THE COLDEST AIR FIRST. CONSIDERING H85 VALUES WILL BE NEAR -15C...SHALLOW ARCTIC AIRMASS...DID KEEP TEMPS A FEW DEGREES BELOW COLDEST GUIDANCE FOR MIN/MAX ON FRIDAY. WILL ALSO NEED A WIND ADVISORY FOR NW NC AND POSSIBLY PART OF THE BLUE RIDGE IN VA THURSDAY AND THURSDAY NIGHT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... TIMING OF THE SATURDAY SYSTEM IS SIMILAR TO YESTERDAY...ALTHOUGH MAY BE SLOWER BY A FEW HOURS. STILL LOOKING AT BEST CHANCE OF PRECIP ARRIVING IN THE WEST DURING THE DAY AND MOVING EAST BY EVENING WITH UPSLOPE SNOW SHOWERS ON THE BACK SIDE LASTING INTO SUNDAY. AFTER THIS THE PATTERN FLATTENS WITH A BACKDOOR FRONT STRETCHING INTO THE MID ATLANTIC BY TUESDAY BUT NO AFFECTS IN TERM OF PRECIP FOR OUR AREA. TEMPS WILL SLOWLY MODERATE AS SFC HIGH SETTLES ACROSS THE AREA SUN-MON. THE 12Z ECMWF MODEL HAS A DIFFERENT SOLUTION INTO MONDAY AS IT FORMS A NEW LOW ALONG THE FRONT IN THE SOUTHEAST SUNDAY MORNING AND SHIFTS IT OFF THE NORTH CAROLINA/VIRGINIA COAST BY 12Z MONDAY. THIS SYSTEM WOULD BRING A GOOD SNOW TO PORTIONS OF THE AREA IF IT PANS OUT...BUT ATTM...THE OTHER MODELS ARE NOT FAVORING IT. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... RADAR RETURNS NOT PRODUCING MUCH AT THE GROUND THIS HOUR...AND WILL PROBABLY BE THE CASE OVER THE NEXT FEW HOURS WITH VERY DRY LLVLS. WOULD THINK THOUGH THERE IS A GOOD CHANCE FOR ICING ALOFT OF AIRCRAFT HOWEVER WITH THIS SETUP. VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING AS HIGH PRESSURE MAINTAINS CONTROL OF OUR AREA. OVERNIGHT...A SYSTEM WILL SWEEP THROUGH THE AREA BRINGING MVFR/IFR CIGS AND MAINLY MVFR VSBYS STARTING BETWEEN 08-12Z FROM WEST TO EAST. ACCOMPANYING THIS CLOUD COVER WILL BE A BRIEF SHOT OF SNOW/SLEET/FZRA BEFORE QUICKLY CHANGING OVER TO ALL RAIN. THE WINTRY MIX WILL LAST LONGEST AT LWB...AND SHORTEST AT BLF. AREAS OF SOUTHEAST WEST VIRGINIA AND PARTS OF SOUTHWEST VIRGINIA ALONG AND NORTH OF A KROA-KLYH LINE CAN EXPECT SNOW OR SLEET AT THE ONSET OF THE PRECIPITATION FOR A FEW HOURS. ELSEWHERE...RAIN IS EXPECTED AT THE ONSET OF THE PRECIPITATION. DURING THE MORNING WEDNESDAY...WARMER AIR ENTERING THE REGION WILL ALLOW FOR A TRANISTION TO ALL RAIN ACROSS THE AREA. THE CIG/VSBY RESTRICTIONS WILL LIKELY CONTINUE THROUGH WEDNESDAY NIGHT UNTIL A COLD FRONT MOVES THROUGH BY THURSDAY MORNING. SCT RAIN AND SNOW SHOWERS WILL CONTINUE IN THE WESTERN MOUNTAINS IN A COLD NORTHWEST FLOW THURSDAY AND FRIDAY. STRONG WINDS CAN BE EXPECTED THURSDAY/THURSDAY NIGHT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VAZ020-024- 035. NC...NONE. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...PM SHORT TERM...KM LONG TERM...WP AVIATION...KM/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
337 AM EST WED FEB 18 2009 .SYNOPSIS... HIGH PRESSURE OVER THE REGION WILL MOVE OFF THE COAST OVERNIGHT. MORE WINTRY PRECIPITATION IS EXPECTED LATE TONIGHT AND WEDNESDAY AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE REGION WEDNESDAY NIGHT. COLD AND WINDY CONDITIONS ALONG WITH SNOW SHOWERS WILL PERSIST INTO THE LATTER PART OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPSTREAM RADAR CONTINUES TO SHOW PRECIP MOVG INTO THE MTNS IN BANDED WAVES. NOT REAL GOOD COVERAGE...BUT ENOUGH FOR LIKELY POPS IN THE SW MTNS OF VA AND THE NRN MTNS OF NC LATE THIS EVENING. I HAVE ALSO PUSHED THE CHC POPS FURTHER EAST LATE THIS EVENING...THOUGH IT IS QUESTIONABLE THAT MEASURABLE PRECIP WILL REACH THE GROUND DESPITE RETURNS ON RADAR. HAVE KEPT THE CATEGORICAL/HIGH LIKELY POPS AFTER 09Z THAT WE HAD GOING. THINK BY THEN THE ATMOSPHERE WILL BE NEARLY SATURATED...AND ISENTROPIC LIFT CONTINUES INTO THE AREA. MAIN QUESTION IS P-TYPE AND WHEN IT CHANGES...AS THE WARM ADVECTION CONTINUES AS WELL. THE 00Z RNK SOUNDING HAS A WET BULB ENTIRELY BELOW ZERO...BUT THE COLUMN WILL BE WARMING FROM THE TOP DOWN CHANGING THE PRECIP FROM WHAT WILL LIKELY BE A SNOW/SLEET START INTO LIQUID AFTER JUST A FEW HOURS MOST LOCATIONS. WITHOUT A SFC HIGH PRESSURE TO HOLD A STRONG WEDGE IN PLACE...THE PATTERN DOES NOT LOOK FAVORABLE FOR THE SFC TO REMAIN COLD FOR MUCH FREEZING RAIN EITHER. BEST CHC FOR MUCH ACCUMULATION LOOKS TO BE IN THE NE- GREENBRIER...BATH... ROCKBRIDGE AND AMHERST COUNTIES. HOWEVER...WITH WHAT IS LIKELY TO BE A SNOW/SLEET MIX...WILL BE TOUGH TO GET MUCH MORE THAN AN INCH. I HAVE LOWERED WON ACCUM AMOUNTS THROUGH 12Z...THEN LEFT THE LIGHT AMOUNTS THAT WE HAD GOING IN THE NE BETWEEN 12 AND 15Z. FCST LOWS LOOKED ON TRACK...UPPER 20S TO MID 30S...WITH MINOR ADJUSTMENTS. THERE IS STILL SOME POTENTIAL FOR SNOW/SLEET ON THE ROADS RIGHT AT THE TIME OF THE MORNING COMMUTE...SO WILL KEEP A MENTION IN THE HAZARDOUS WEATHER OUTLOOK WHERE WE HAVE ANY SNOW OR SLEET IN THE FCST. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... BIGGEST CONCERN FOR THIS PART OF THE PACKAGE IS WINDS AND UPSLOPE SNOW. DEBATING WHETHER OR NOT TO ISSUE AN ELEVATION WATCH FOR GREENBRIER. HOWEVER...NAM12 H7 MOISTURE IS FARTHER NORTH AND MOISTURE DEPTH IS MORE SHALLOW THAN THE PAST FEW NIGHTS. SEEMS AS THOUGH THE DEEPEST MOISTURE WILL BE AROUND FROM MID MORNING THURS THROUGH EARLY AFTERNOON. ATTM...THE BEST COURSE OF ACTION WOULD BE A SNOW ADVISORY SAY FROM GREENBRIER TO TAZEWELL FROM THURS INTO THURS NIGHT BUT THIS CAN BE FINE TUNED ON FUTURE SHIFTS. ABOVE 2500 FEET IN GREENBRIER MAY BE CLOSE OR JUST ABV WARNING CRITERIA BY FRIDAY MORNING AND THIS CAN BE HANDLED IN AN ADVISORY TOO. ANOTHER ISSUE IS THE WIND WHICH WILL BE BLOWING THE SNOW AROUND. NONETHELESS...IT WILL BE SNOWING HARD AT TIMES WITH WINDS GREATLY REDUCING VISIBILITIES IN THESE SPOTS THURS AND THURS NIGHT. A COUPLE INCHES MAY ALSO FALL IN THE SKI COUNTRY OF NW NC WITH AN INCH OR LESS AT THE LOWER ELEVATIONS. IF WINDS STAY UP...WIND CHILL ADVISORY CRITERIA MAY BE MET INTO FRIDAY MORNING FOR THE EXTREME SW...WHICH WILL RECEIVE THE COLDEST AIR FIRST. CONSIDERING H85 VALUES WILL BE NEAR -15C...SHALLOW ARCTIC AIRMASS...DID KEEP TEMPS A FEW DEGREES BELOW COLDEST GUIDANCE FOR MIN/MAX ON FRIDAY. WILL ALSO NEED A WIND ADVISORY FOR NW NC AND POSSIBLY PART OF THE BLUE RIDGE IN VA THURSDAY AND THURSDAY NIGHT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... TIMING OF THE SATURDAY SYSTEM IS SIMILAR TO YESTERDAY...ALTHOUGH MAY BE SLOWER BY A FEW HOURS. STILL LOOKING AT BEST CHANCE OF PRECIP ARRIVING IN THE WEST DURING THE DAY AND MOVING EAST BY EVENING WITH UPSLOPE SNOW SHOWERS ON THE BACK SIDE LASTING INTO SUNDAY. AFTER THIS THE PATTERN FLATTENS WITH A BACKDOOR FRONT STRETCHING INTO THE MID ATLANTIC BY TUESDAY BUT NO AFFECTS IN TERM OF PRECIP FOR OUR AREA. TEMPS WILL SLOWLY MODERATE AS SFC HIGH SETTLES ACROSS THE AREA SUN-MON. THE 12Z ECMWF MODEL HAS A DIFFERENT SOLUTION INTO MONDAY AS IT FORMS A NEW LOW ALONG THE FRONT IN THE SOUTHEAST SUNDAY MORNING AND SHIFTS IT OFF THE NORTH CAROLINA/VIRGINIA COAST BY 12Z MONDAY. THIS SYSTEM WOULD BRING A GOOD SNOW TO PORTIONS OF THE AREA IF IT PANS OUT...BUT ATTM...THE OTHER MODELS ARE NOT FAVORING IT. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... RADAR RETURNS NOT PRODUCING MUCH AT THE GROUND THIS HOUR...AND WILL PROBABLY BE THE CASE OVER THE NEXT FEW HOURS WITH VERY DRY LLVLS. WOULD THINK THOUGH THERE IS A GOOD CHANCE FOR ICING ALOFT OF AIRCRAFT HOWEVER WITH THIS SETUP. VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING AS HIGH PRESSURE MAINTAINS CONTROL OF OUR AREA. OVERNIGHT...A SYSTEM WILL SWEEP THROUGH THE AREA BRINGING MVFR/IFR CIGS AND MAINLY MVFR VSBYS STARTING BETWEEN 08-12Z FROM WEST TO EAST. ACCOMPANYING THIS CLOUD COVER WILL BE A BRIEF SHOT OF SNOW/SLEET/FZRA BEFORE QUICKLY CHANGING OVER TO ALL RAIN. THE WINTRY MIX WILL LAST LONGEST AT LWB...AND SHORTEST AT BLF. AREAS OF SOUTHEAST WEST VIRGINIA AND PARTS OF SOUTHWEST VIRGINIA ALONG AND NORTH OF A KROA-KLYH LINE CAN EXPECT SNOW OR SLEET AT THE ONSET OF THE PRECIPITATION FOR A FEW HOURS. ELSEWHERE...RAIN IS EXPECTED AT THE ONSET OF THE PRECIPITATION. DURING THE MORNING WEDNESDAY...WARMER AIR ENTERING THE REGION WILL ALLOW FOR A TRANISTION TO ALL RAIN ACROSS THE AREA. THE CIG/VSBY RESTRICTIONS WILL LIKELY CONTINUE THROUGH WEDNESDAY NIGHT UNTIL A COLD FRONT MOVES THROUGH BY THURSDAY MORNING. SCT RAIN AND SNOW SHOWERS WILL CONTINUE IN THE WESTERN MOUNTAINS IN A COLD NORTHWEST FLOW THURSDAY AND FRIDAY. STRONG WINDS CAN BE EXPECTED THURSDAY/THURSDAY NIGHT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS/JJ SHORT TERM...KM LONG TERM...WP AVIATION...KM/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1157 PM EST TUE FEB 17 2009 .SYNOPSIS... HIGH PRESSURE OVER THE REGION WILL MOVE OFF THE COAST OVERNIGHT. MORE WINTRY PRECIPITATION IS EXPECTED LATE TONIGHT AND WEDNESDAY AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE REGION WEDNESDAY NIGHT. COLD AND WINDY CONDITIONS ALONG WITH SNOW SHOWERS WILL PERSIST INTO THE LATTER PART OF THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... UPSTREAM RADAR CONTINUES TO SHOW PRECIP MOVG INTO THE MTNS IN BANDED WAVES. NOT REAL GOOD COVERAGE...BUT ENOUGH FOR LIKELY POPS IN THE SW MTNS OF VA AND THE NRN MTNS OF NC LATE THIS EVENING. I HAVE ALSO PUSHED THE CHC POPS FURTHER EAST LATE THIS EVENING...THOUGH IT IS QUESTIONABLE THAT MEASURABLE PRECIP WILL REACH THE GROUND DESPITE RETURNS ON RADAR. HAVE KEPT THE CATEGORICAL/HIGH LIKELY POPS AFTER 09Z THAT WE HAD GOING. THINK BY THEN THE ATMOSPHERE WILL BE NEARLY SATURATED...AND ISENTROPIC LIFT CONTINUES INTO THE AREA. MAIN QUESTION IS P-TYPE AND WHEN IT CHANGES...AS THE WARM ADVECTION CONTINUES AS WELL. THE 00Z RNK SOUNDING HAS A WET BULB ENTIRELY BELOW ZERO...BUT THE COLUMN WILL BE WARMING FROM THE TOP DOWN CHANGING THE PRECIP FROM WHAT WILL LIKELY BE A SNOW/SLEET START INTO LIQUID AFTER JUST A FEW HOURS MOST LOCATIONS. WITHOUT A SFC HIGH PRESSURE TO HOLD A STRONG WEDGE IN PLACE...THE PATTERN DOES NOT LOOK FAVORABLE FOR THE SFC TO REMAIN COLD FOR MUCH FREEZING RAIN EITHER. BEST CHC FOR MUCH ACCUMULATION LOOKS TO BE IN THE NE- GREENBRIER...BATH... ROCKBRIDGE AND AMHERST COUNTIES. HOWEVER...WITH WHAT IS LIKELY TO BE A SNOW/SLEET MIX...WILL BE TOUGH TO GET MUCH MORE THAN AN INCH. I HAVE LOWERED WON ACCUM AMOUNTS THROUGH 12Z...THEN LEFT THE LIGHT AMOUNTS THAT WE HAD GOING IN THE NE BETWEEN 12 AND 15Z. FCST LOWS LOOKED ON TRACK...UPPER 20S TO MID 30S...WITH MINOR ADJUSTMENTS. THERE IS STILL SOME POTENTIAL FOR SNOW/SLEET ON THE ROADS RIGHT AT THE TIME OF THE MORNING COMMUTE...SO WILL KEEP A MENTION IN THE HAZARDOUS WEATHER OUTLOOK WHERE WE HAVE ANY SNOW OR SLEET IN THE FCST. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... WEDNESDAY NIGHT...THEN FRONT WILL BE PUSHING ACROSS THE AREA AND BE NEAR THE BLUE RIDGE AROUND 06Z THU. AROUND 12Z THU...THE FRONT WILL BE WELL EAST OF THE AREA...BUT THE DEW POINT FRONT AND STRONGER COLD AIR WILL BE DELAYED A BIT. WITH THE LOW BECOMING OCCLUDED OVER LAKE ERIE...RAIN SHOWERS WILL PERSIST DURING THE EVENING BUT DECREASE IN COVERAGE. AFTER 06Z THU...SOME LIGHT RAIN/DRIZZLE MAY LINGER ACROSS THE MOUNTAINS WITH HIGHER ELEVATIONS TRANSITIONING OVER TO SNOW. THURSDAY AFTERNOON...THIS LOW PRESSURE SYSTEM WILL BE MOVING EAST ACROSS PA. WRAP-A-ROUND MOISTURE AND A WESTERLY FLOW WILL BRING ACCUMULATING SNOW TO WESTERN SLOPES THROUGH FRIDAY. THE DIRECTION OF THE WINDS WILL BE MORE WESTERLY WITH A BRIEF CONNECTION TO THE GREAT LAKES THURSDAY AFTERNOON AND EVENING. AREAS EAST OF THESE SE WV/SW VA/NW NC WESTERN RIDGES WILL SEE VERY LITTLE ACCUMULATION. AFTER 06Z FRI...BULK OF MOISTURE PULLS TO THE NORTH AND BY SUNRISE FRIDAY...SNOW SHOWERS WILL BE PRIMARILY IN SE WV AND NORTH. BY FRIDAY NIGHT...ALL SNOW SHOWERS WILL HAVE EXITED THE AREA. ELEVATION/ASPECT DEPENDANT ADVISORIES/WARNING MAY NEED TO BE ISSUED FOR THIS EVENT. WE STILL HAVE ANOTHER 24 HOURS TO LOOK AT THIS EVENT BUT WILL ONLY HIGHLIGHT IT IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW. FOLLOWING THE FRONTAL PASSAGE THURSDAY MORNING...WINTER WILL MAKE A RETURN AND TEMPERATURES WILL LIKELY REMAIN BELOW NORMAL INTO THE WEEKEND. TEMPERATURES THURSDAY WILL NOT WARM MUCH ACROSS THE MOUNTAINS WITH MORNING HIGHS IN THE 30S. EAST OF THE BLUE RIDGE...DOWNSLOPING MAY ALLOW FOR A NORMAL DIURNAL CURVE BUT WINDY/GUSTY CONDITIONS WILL MAKE IT FEEL COLDER DURING THE AFTERNOON. THE WIND WILL PICK UP THROUGH THE DAY THURSDAY AND REMAIN INTO FRIDAY. WINDS/GUSTS COULD REACH ADVISORY CRITERIA THURSDAY AND THURSDAY NIGHT ALONG THE BLUE RIDGE. && .LONG TERM /SATURDAY THROUGH TUESDAY/... TIMING OF THE SATURDAY SYSTEM IS SIMILAR TO YESTERDAY...ALTHOUGH MAY BE SLOWER BY A FEW HOURS. STILL LOOKING AT BEST CHANCE OF PRECIP ARRIVING IN THE WEST DURING THE DAY AND MOVING EAST BY EVENING WITH UPSLOPE SNOW SHOWERS ON THE BACK SIDE LASTING INTO SUNDAY. AFTER THIS THE PATTERN FLATTENS WITH A BACKDOOR FRONT STRETCHING INTO THE MID ATLANTIC BY TUESDAY BUT NO AFFECTS IN TERM OF PRECIP FOR OUR AREA. TEMPS WILL SLOWLY MODERATE AS SFC HIGH SETTLES ACROSS THE AREA SUN-MON. THE 12Z ECMWF MODEL HAS A DIFFERENT SOLUTION INTO MONDAY AS IT FORMS A NEW LOW ALONG THE FRONT IN THE SOUTHEAST SUNDAY MORNING AND SHIFTS IT OFF THE NORTH CAROLINA/VIRGINIA COAST BY 12Z MONDAY. THIS SYSTEM WOULD BRING A GOOD SNOW TO PORTIONS OF THE AREA IF IT PANS OUT...BUT ATTM...THE OTHER MODELS ARE NOT FAVORING IT. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... RADAR RETURNS NOT PRODUCING MUCH AT THE GROUND THIS HOUR...AND WILL PROBABLY BE THE CASE OVER THE NEXT FEW HOURS WITH VERY DRY LLVLS. WOULD THINK THOUGH THERE IS A GOOD CHANCE FOR ICING ALOFT OF AIRCRAFT HOWEVER WITH THIS SETUP. VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING AS HIGH PRESSURE MAINTAINS CONTROL OF OUR AREA. OVERNIGHT...A SYSTEM WILL SWEEP THROUGH THE AREA BRINGING MVFR/IFR CIGS AND MAINLY MVFR VSBYS STARTING BETWEEN 08-12Z FROM WEST TO EAST. ACCOMPANYING THIS CLOUD COVER WILL BE A BRIEF SHOT OF SNOW/SLEET/FZRA BEFORE QUICKLY CHANGING OVER TO ALL RAIN. THE WINTRY MIX WILL LAST LONGEST AT LWB...AND SHORTEST AT BLF. AREAS OF SOUTHEAST WEST VIRGINIA AND PARTS OF SOUTHWEST VIRGINIA ALONG AND NORTH OF A KROA-KLYH LINE CAN EXPECT SNOW OR SLEET AT THE ONSET OF THE PRECIPITATION FOR A FEW HOURS. ELSEWHERE...RAIN IS EXPECTED AT THE ONSET OF THE PRECIPITATION. DURING THE MORNING WEDNESDAY...WARMER AIR ENTERING THE REGION WILL ALLOW FOR A TRANISTION TO ALL RAIN ACROSS THE AREA. THE CIG/VSBY RESTRICTIONS WILL LIKELY CONTINUE THROUGH WEDNESDAY NIGHT UNTIL A COLD FRONT MOVES THROUGH BY THURSDAY MORNING. SCT RAIN AND SNOW SHOWERS WILL CONTINUE IN THE WESTERN MOUNTAINS IN A COLD NORTHWEST FLOW THURSDAY AND FRIDAY. STRONG WINDS CAN BE EXPECTED THURSDAY/THURSDAY NIGHT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS/JJ SHORT TERM...RCS LONG TERM...WP AVIATION...KM/WP
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
627 AM EST WED FEB 18 2009 .SYNOPSIS... A WARM FRONT WILL MOVE NORTH THROUGH THE REGION THIS AFTERNOON. SHOWERS AND A FEW THUNDERSTORMS ARE ALSO EXPECTED THIS AFTERNOON INTO THIS EVENING. A COLD FRONT WILL MOVE THROUGH FROM THE WEST TONIGHT BRINGING AN END TO THE RAIN. HIGH PRESSURE WILL MOVE OVER THE AREA THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WARM FRONT TO THE SOUTH WILL APPROACH THIS MORNING. ISENTROPIC LIFT NORTH OF FRONT SHOULD ENHANCE PRECIPITATION LATER THIS MORNING. LIKE GOING 100 PERCENT CHANCE. NOTICED GSP HAD SLEET MIXED IN WITH RAIN NORTH OF CAE CWA. RAN TOP DOWN WEATHER TOOL AND IT SHOWED CONDITIONS TOO WARM FOR ANY WINTRY MIX. SO LEFT OUT. EVEN THOUGH WARM FRONT MOVES NORTH...NAM IS SHOWING LOW LEVEL INVERSION PERSISTS JUST ABOUT ALL DAY. HAD CONSIDERED THE POSSIBILITY OF H925 AND H850 WINDS MIXING DOWN IF WAA FROM SOUTH WAS SUFFICIENT. H925 WINDS SW 45 KT. H8 WINDS INCREASE TO 65 KT THIS AFTERNOON BUT DIRECTION BECOMES MORE WEST IMPLYING WEAKER WAA. SO DECIDED TO KEEP WIND SPEEDS BELOW LAKE WIND ADVY CRITERIA, ALSO...STRONG SHEAR APPROACHING FROM THE WEST REMAINS NORTH OF THE WARM FRONT AND EXITS AREA TO NORTH BY ABOUT 18Z. EVEN THOUGH WEAK WARM FRONT MOVES THROUGH...WILL KEEP HIGH TEMPERATURES MOSTLY IN THE 50S. WILL HAVE SOME LOWER 60S EXTREME SOUTH PART. WILL KEEP MENTION OF CHANCE OF THUNDERSTORMS BUT FEEL CONVECTION WILL BE MAINLY ALOFT. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... BEST CHANCE OF THUNDERSTORMS IS THIS EVENING. ISOLATED SEVERE STORMS POSSIBLE MAINLY CSRA BUT CAN`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
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
559 AM CST WED FEB 18 2009 .DISCUSSION... 338 AM CST FOG THIS MORNING...PRECIP TYPE AND AMOUNTS WITH STORM SYSTEM FOR TODAY...AND ANOTHER STRONG CLIPPER SYSTEM FOR LATE FRIDAY WILL BE THE MAIN FORECAST CONCERNS. ELEVATED THUNDER HAS DEVELOPED OVERNIGHT ACROSS WEST CENTRAL ILLINOIS...AND THESE SHOWERS CONTINUE TO TRACK ACROSS NORTHEAST ILLINOIS EARLY THIS MORNING. STEEPEST MID LEVEL LAPSE RATES ARE IN PLACE AT THIS TIME WITH LOCAL ACARS SOUNDINGS SUGGESTING NEAR DRY ADIABATIC LAPSE RATES IN THE 700 HPA TO 500 HPA LAYER. THESE SHOWERS AND PERHAPS ISOLATED THUNDERSTORM WILL RACE INTO NORTHWEST INDIANA OVER NEXT FEW HOURS BUT AN ADDITIONAL AREA OF PRECIPITATION CONTINUES TO DEVELOP ACROSS SOUTHEAST IOWA BEHIND THESE ELEVATED SHOWERS. THIS DEVELOPING AREA OF PRECIPITATION SEEMS TO BE MORE RELATED TO DEFORMATION FORCING JUST NORTH OF THE LEAD SHORT WAVE MOVING ACROSS SOUTH CENTRAL IOWA/NORTHERN MISSOURI. LOW/MID LEVEL FRONTOGENESIS WILL LIKELY STRENGTHEN THIS MORNING VIA STRENGTHENING WESTERLY LOW/MID LEVEL FLOW ASSOCIATED WITH THIS NORTHERN STREAM TROUGH DIGGING ACROSS THE NORTHERN PLAINS PER WATER VAPOR IMAGERY THIS MORNING. PAST SEVERAL MODEL RUNS HAVE HAD SOME INDICATION OF THIS FEATURE AND MAIN FORECAST QUESTION WILL BE PRECIP TYPES AS IT MOVES ACROSS CWA THIS MORNING. SURFACE LOW EVOLUTION SEEMS TO BE PANNING OUT IN A WAY FAIRLY SIMILAR TO WHAT PAST SEVERAL NAM/WRF RUNS HAVE DEPICTED WITH MORE PRONOUNCED PRESSURE FALLS ACROSS SOUTHERN WISCONSIN AND SECONDARY SFC LOW DEVELOPMENT. THIS HAS RESULTED IN MORE OF AN ELONGATED SURFACE TROUGH EXTENDING FROM MAIN SFC LOW ACROSS NORTHERN MISSOURI INTO EAST CENTRAL WISCONSIN. COLD AIR SHOULD BE SOMEWHAT SLOW TO BE DRAWN SOUTHWARD TODAY GIVEN THIS TYPE OF PATTERN AND RUC/NAM/GFS THERMAL PROFILES REMAIN QUITE MARGINAL IN REGARDS TO RAIN/SNOW PRECIP TYPE MID TO LATE MORNING. BY MID MORNING MOST OF THE COLUMN SHOULD BE BELOW FREEZING WITH MAIN QUESTION AS TO TRENDS WITH TEMPS/WET BULBS IN VERY LOWEST LEVELS. EXPECTING MOST OF THE PRECIPITATION THIS MORNING WILL BE LIQUID BUT COULD HAVE A BRIEF PERIOD OF DECENT WET SNOWFALL RATES ASSOCIATED WITH THE FRONTOGENESIS FORCING BEFORE TAPERING OFF. IF THE PRECIP DOES CHANGE OVER TO SNOW BEFORE TAPERING OFF TOWARD MIDDAY...WARMISH LOW LEVELS WILL LIKELY MAKE ANY APPRECIABLE SNOW ACCUMULATION HARD TO COME BY. HAVE DECREASED SNOW ACCUMULATIONS TODAY AND TRIED TO SHOW A RELATIVELY NARROW CORRIDOR WHERE SOME MINOR ACCUMS OF AN INCH OR LESS WOULD BE POSSIBLE ALONG OR JUST NORTH OF INTERSTATE 80 CORRIDOR WHERE THIS FRONTOGENESIS FORCING IS FORECAST BE MOST PRONOUNCED. THE AFOREMENTIONED SFC TROUGH EXTENDING INTO NORTH CENTRAL ILLINOIS HAS LED TO A WEAK SFC PRESSURE GRADIENT. THE WEAK GRADIENT COMBINED WITH LOW LEVEL MOISTURE HAVING ADVECTED INTO THE AREA HAS RESULTED IN SOME FOG...LOCALLY DENSE. WILL BE ISSUING A DENSE FOG ADVISORY THROUGH MID MORNING MAINLY FOR NORTHERN HALF OF THE FORECAST AREA...NORTH OF THE SFC LOW TRACK. THE THREAT OF ANY THUNDER SHOULD WANE BY MID MORNING AS STEEPER MID LEVEL LAPSE RATES SHIFT EAST OF THE AREA. STRONGER DPVA WITH THE NORTHERN STREAM SHORT WAVE WILL NOT LIKELY IMPACT NORTHEAST ILLINOIS/NORTHWEST INDIANA UNTIL THIS EVENING SO EXPECTING A LULL IN PRECIP THIS AFTERNOON. DID KEEP SOME LIKELY POPS GOING FOR SNOW SHOWERS ACROSS NORTHEAST ILLINOIS INTO NORTHWEST INDIANA BUT ACCUMULATIONS SHOULD MINOR...GENERALLY LESS THAN A HALF INCH. POSSIBLE EXCEPTION TO THIS IS FOR PORTIONS OF NORTHWEST INDIANA WHERE STRONGEST DPVA IS EXPECTED TO OCCUR ON TOP OF LAKE EFFECT SNOW POTENTIAL. LAKE INDUCED EQUIL. LEVELS INCREASE TO AROUND 9K FT TONIGHT AS COLDER AIR DROPS SOUTHWARD INTO THE AREA. IT STILL APPEARS AS THOUGH A NORTHWEST LOW LEVEL FLOW COMPONENT SHOULD FAVOR HEAVIER LAKE EFFECT ACCUMULATIONS EAST OF PORTER COUNTY. COMBINATION OF LAKE EFFECT AND SYNOPTIC FORCING MAY PRODUCE A FEW INCHES OF SNOW ACCUMULATION THIS EVENING HOWEVER. WINDS WILL STRENGTHEN AS COLD ADVECTION INTENSIFIES THIS EVENING WITH SOME GUSTS TO 35 MPH POSSIBLE BY THIS EVENING AND WILL CONTINUE THROUGH THE NIGHT. MUCH COLDER TEMPERATURES IN STORE FOR THURSDAY WITH MODELS CONTINUING TO BRING DOWN 850 HPA TEMPS OF -18 TO -20 DEG CELS. GOING HIGHS FROM AROUND 20 FAR NORTH TO MID 20S SOUTH STILL APPEARS TO BE IN THE BALLPARK. A FEW LINGERING LAKE EFFECT SNOW SHOWERS MAY AFFECT PORTER COUNTY INTO THURSDAY. COLDEST NIGHT OF THE PERIOD WILL LIKELY BE ON THURSDAY NIGHT WITH LESS CLOUD COVER AND WINDS BEGINNING TO SLACKEN OFF A BIT. ATTENTION THEN TURNS TO NEXT CLIPPER SYSTEM TO AFFECT THE AREA FRIDAY NIGHT INTO EARLY SATURDAY. OVERALL THERE HAS BEEN SOME DECENT RUN TO RUN CONSISTENCY WITH THIS FEATURE...JUST SOME EXPECTED DIFFERENCES IN THE STRENGTH OF THE UPPER LEVEL WAVE. HAVE TRENDED TOWARD SREF/GFS IDEA OF SFC LOW TRACKING THROUGH CENTRAL ILLINOIS FRIDAY EVENING. SOME IMPRESSIVE ISENTROPIC ASCENT WOULD ALSO ACCOMPANY THIS WAVE ASSUMING THIS SOLUTION VERIFIES WHICH COULD SPREAD ADVISORY LEVEL SNOW ACCUMULATIONS ACROSS THE AREA FRIDAY NIGHT. DID INCREASE POPS FOR FRIDAY NIGHT...AND IF THIS SOLUTION REMAINS CONSISTENT WILL LIKELY NEED TO BEEF UP THIS MENTION IN NEXT FEW FORECASTS. REINFORCING COLD AIR WILL MOVE IN BEHIND THIS SYSTEM FOR THE WEEKEND...FOLLOWED BY DRY CONDITIONS AND MODERATING TEMPS FOR MONDAY AS UPPER FLOW DEAMPLIFIES. MARSILI && .AVIATION... 1200 UTC TAFS...TAF CONCERNS ARE MANY THIS MORNING..WITH TRENDS WITH RESPECT TO VLIFR/LIFR/IFR CEILINGS/VSBYS AND PRECIP TYPE MAIN FOCI OF FORECAST. 11Z/5 AM CST SURFACE ANALYSIS DEPICTS SURFACE LOW PRESSURE OVER WESTERN IL VICINITY KMQB. INVERTED TROUGH EXTENDS NORTHEAST THROUGH KRFD INTO WI...WHILE PSEUDO WARMFRONT EXTENDS NORTHEAST/EAST TOWARD CHICAGO. WEAKENING OF PRESSURE GRADIENT AND RESULTING LIGHT SURFACE WINDS IN PROXIMITY TO TROUGH ACROSS NORTHERN ILLINOIS HAS ALLOWED VLIFR CONDITIONS TO DEVELOP OVERNIGHT IN SATURATED LOW LEVEL AIRMASS. VISIBILITIES OF 1/8 TO 1/2 MILE HAVE BEEN COMMON WITH CEILINGS 100-200 FEET NORTH OF PSEUDO WARM FRONTAL FEATURE...WHILE REMAINING LIFR SOUTH OF THIS FEATURE WITH VSBYS STILL A COUPLE OF MILES OR BETTER. IN ADDITION...A PAIR OF MID LEVEL SHORT WAVES HAVE BROUGHT RAIN ACROSS THE AREA ALONG AND SOUTH OF THE INTERSTATE 88 CORRIDOR FROM ROUGHLY KSQI TO KORD...AND THIS IS HELPING TO IMPROVE VISIBILITY IN AREAS WHERE HEAVIER RAIN FALLS. SECOND MID LEVEL WAVE IS NOW ENTERING WESTERN IL...AND WILL TRANSITION FORECAST AREA THROUGH MID MORNING. 06Z NAM TAKES THIS FEATURE AND ASSOCIATED SURFACE LOW/TROUGH TO THE IL/IN STATE LINE BY AROUND 1530Z...WITH SOME IMPROVEMENT ABOVE VLIFR EXPECTED EARLY DUE TO INCREASE IN RAIN ACROSS THE AREA. AREA OF ELEVATED THUNDERSTORMS NEAR KFSW EXPECTED TO REMAIN OFF TO THE SOUTH OF THE TERMINALS AS WAVE MOVES EAST THIS MORNING. RAIN WILL SHIFT EAST OF THE AREA BY MID MORNING AS WAVE DEPARTS...THOUGH SECOND AREA OF LIGHT PRECIPITATION ASSOCIATED WITH WEAK DEFORMATION BAND NOW MOVING INTO NORTHWEST IL WILL PUSH ACROSS THE AREA THROUGH LATE MORNING. LOW LEVEL WIND SHIFT TO NORTHWEST BEHIND SURFACE TROUGH WILL RESULT IN COOLING OF COLUMN AND CHANGEOVER OF LIGHT RAIN TO LIGHT RAIN/SNOW MIX OR SNOW. PRECIP SHOULD END BY LATE MORNING FROM WEST TO EAST AS THIS DEFORMATION BAND MOVES EAST. INCREASING NORTHWEST LOW LEVEL WIND FIELD SHOULD HELP MAINTAIN SLOW IMPROVEMENT IN VISIBILITY THROUGH THE MORNING/EARLY AFTERNOON...THOUGH FORECAST SOUNDINGS AND CURRENT UPSTREAM CONDITIONS INDICATE TERMINALS WILL REMAIN IFR THROUGH THE DAY. ANOTHER MID LEVEL TROUGH DROPS SOUTHEAST ACROSS THE FORECAST AREA LATE THIS AFTERNOON/EVENING PRESENTING THE POTENTIAL FOR A PERIOD OF SNOW SHOWERS. 06Z NAM MAINTAINS TREND OF CENTERING THIS PERIOD OF SNOW A COUPLE OF HOURS AROUND 00Z/6 PM CST...BEFORE SHIFTING EAST OF THE FORECAST AREA MID/LATE EVENING. WHILE A FEW FLURRIES MAY LINGER FROM MVFR STRATOCU DECK INTO THE OVERNIGHT HOURS...REMAINDER OF FORECAST SHOULD ENJOY A GRADUAL LIFTING OF MVFR CEILINGS. RATZER && .MARINE... 313 AM CST LOW PRESSURE OVER FAR NORTHEAST MISSOURI THIS MORNING WILL CONTINUE TO TRACK EAST/NORTHEAST ACROSS NORTHERN ILLINOIS THIS MORNING...WHILE WEAKER TROUGH EXTENDING NORTH INTO WISCONSIN PASSES ACROSS LAKE MICHIGAN. WINDS HAVE DECREASED AS GRADIENT BECOMES WEAKER IN VICINITY OF THIS TROUGH EARLY THIS MORNING... BUT WILL STRENGTHEN AGAIN LATER THIS MORNING FROM THE NORTH AS THE TROUGH/LOW MOVE EAST OF THE LAKE AND CONTINUE TO DEEPEN. STRENGTHENING LOW AND STRONG LOW LEVEL COLD ADVECTION TO FOLLOW STILL APPEAR TO SUPPORT ABOUT A 30 HOUR PERIOD OF 35-40 KNOT NORTH TO NORTHWEST GALES ACROSS THE LAKE BEGINNING ON THE NORTH END EARLY THIS AFTERNOON...AND SPREADING SOUTH ACROSS THE REMAINDER OF THE LAKE BY EARLY THIS EVENING. FAR SOUTH/SOUTHWEST PARTS OF THE LAKE WILL LIKELY BE LAST TO SEE WINDS INCREASE TO GALE FORCE...LATE AFTERNOON OR TOWARD THIS EVENING...THOUGH AM HESITANT TO CHANGE EXISTING GALE WARNING START TIME AS WILL BE A GRADUAL INCREASE FROM THE NORTH THROUGH THE AFTERNOON. TIMING OF HEAVY FREEZING SPRAY HEADLINES LOOKS GOOD. WINDS SHOULD GRADUALLY DECREASE OVERNIGHT THURSDAY NIGHT AS HIGH PRESSURE RIDGE BUILDS SOUTH ACROSS PLAINS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014 UNTIL 10 AM WEDNESDAY. IN...NONE. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878...NOON WEDNESDAY TO MIDNIGHT FRIDAY. HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779- LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 PM WEDNESDAY TO 6 PM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
915 AM EST WED FEB 18 2009 .UPDATE... MADE A FEW TWEAKS TO THE FORECAST. RATHER SOLID AREA OF LIGHT RAIN FORMED EARLIER OVER SOUTHERN INDIANA AND CONTINUES TO SLIDE TO THE ESE ACROSS SOUTHERN INDIANA AND INTO NORTHERN CENTRAL KENTUCKY. UPPED MORNING POPS TO CATEGORICAL IN THE AREAS THAT ARE TO BE AFFECTED BY THIS AREA OF RAIN. ALSO...REDUCED MORNING POPS IN THE SOUTH WHERE THE RAIN WILL MISS AND PROSPECTS FOR DEVELOPMENT THIS MORNING ARE SLIMMER. KEPT POPS IN THE CHANCE CATEGORY IN THE SOUTH. NO OTHER SIGNIFICANT CHANGES AT THIS TIME. && .SHORT TERM (TODAY AND TONIGHT)... MASS OF WARM-AIR ADVECTION SHOWERS AND STORMS ARE AFFECTING MUCH OF THE SOUTHERN CWA. A FEW STRONG STORMS HAVE FORMED WITHIN THE MASS...PRODUCING PEA SIZE HAIL NEAR BOWLING GREEN. ONE STORM THAT PRODUCED NICKEL HAIL NEAR THE KY/TN BORDER MOVED ACROSS LOGAN AND SIMPSON BUT HAS SINCE WANED. EVERYTHING NOW IS BEHAVING...WITH HEAVY RAINFALL TRAINING OVER THE SAME AREAS...AND LOTS OF LIGHTNING. GUSTY WINDS ARE ALSO OCCURRING...WITH PEAKS AROUND 40-45 MPH. BUT RECENT ACARS SOUNDINGS SHOW NICE CAPPING AT 800MB...SO ANY SEVERE WIND GUSTS MIXING DOWN SHOULD NOT OCCUR. THROUGH SUNRISE...ANY STRONG STORM WILL BE CAPABLE OF PRODUCING PEA AND MARBLE SIZE HAIL. THIS AREA OF SHOWERS AND STORMS IS ALL AHEAD OF AN APPROACHING LOW PRESSURE CENTER OVER NW MISSOURI. THIS LOW WILL PUSH TOWARDS NE INDIANA TODAY...WHICH WILL ALSO PUSH THESE SHOWERS AND STORMS EAST OF THE CWA MOSTLY BY 18Z. THEN THE COLD FRONT FROM THE LOW WILL PASS THROUGH THE CWA BETWEEN ROUGHLY 21Z AND 03Z. THE NMM-WRF HAS A GOOD HANDLE ON CURRENT PRECIP...AND THAT MODEL SHOWS MORE SHOWERS/STORMS DEVELOPING OVER OUR ERN CWA ALONG THE COLD FRONT. ASSUMING THE CAP ALOFT CAN BREAK THIS AFTERNOON...WILL GO WITH THIS MODEL SOLUTION AND HAVE THE HIGHEST POPS OVER THE ERN HALF OF THE CWA. DESPITE CLOUDS AND PRECIP...TEMPS SHOULD CLIMB ESPECIALLY THIS AFTERNOON INTO THE MID 50S N TO THE MID 60S S. WINDS WILL CONTINUE TO BE GUSTY...ESPECIALLY LATER THIS AFTERNOON AHEAD OF THE COLD FRONT...WITH GUSTS UP TO 35 MPH BEING POSSIBLE. TONIGHT...ON THE BACK SIDE OF THE LOW/FRONT...TEMPS SHOULD FALL INTO THE UPPER 20S AND LOW 30S. RESIDUAL WRAP-AROUND MOISTURE WILL AFFECT MAINLY OUR NERN CWA OVERNIGHT...WHERE RAIN WILL CHANGE TO SNOW SHOWERS. THIS WILL MOST LIKELY OCCUR OVER THE NORTHERN BLUEGRASS AFTER MIDNIGHT TOWARDS DAWN THURSDAY. .LONG TERM (THURSDAY THROUGH TUESDAY)... NOT TOO MANY CHANGES REQUIRED THROUGH THE EXTENDED THIS MORNING. MAIN CHALLENGES WILL BE MOVING OUT PRECIPITATION ON THURSDAY AND ANOTHER CLIPPER SYSTEM BRINGING A CHANCE FOR LIGHT ACCUMULATING SNOW ON SATURDAY. A WEAK DISTURBANCE ON TUESDAY NEAR THE END OF THE FORECAST PERIOD COULD ALSO BRING ANOTHER ROUND OF PRECIPITATION. THURSDAY THROUGH SATURDAY... UPPER LEVEL LOW OVER MICHIGAN WILL MOVE EASTWARD INTO UPSTATE NEW YORK PULLING SURFACE LOW INTO THE NORTHEAST U.S. NORTHWEST FLOW ACROSS THE AREA WILL USHER IN HIGH SURFACE PRESSURE AND LINGERING PRECIPITATION SHOULD MOVE EAST OF THE AREA BY MIDDAY WITH SOME FLURRIES POSSIBLE ACROSS NORTH CENTRAL KY AND THE BLUEGRASS REGION IN THE AFTERNOON BEFORE DRIER CONDITIONS SET IN THURSDAY NIGHT AND FRIDAY. WITH HIGHS ONLY TOPPING OUT IN THE LOW 30S ON THURSDAY AND CLEARING SKIES OVERNIGHT TEMPS WILL BOTTOM OUT IN THE TEENS BY FRIDAY MORNING. PLENTY OF SUNSHINE ON FRIDAY AND SOME LOW LEVEL WAA WILL ALLOW TEMPS TO REBOUND INTO THE MID 40S IN THE SOUTHWEST TO THE UPPER 30S IN THE NORTHEAST. CLOUDS WILL INCREASE DURING THE LATE AFTERNOON AND EARLY EVENING ON FRIDAY AS THE NEXT CLIPPER SYSTEM APPROACHES THE AREA LATE FRIDAY NIGHT AND SATURDAY. EXPECT A MIX OF RAIN/SNOW LATE FRIDAY EVENING MAINLY ACROSS AREAS WEST OF INTERSTATE 65 WITH PRECIPITATION SPREADING EASTWARD TOWARD SATURDAY MORNING AND CHANGING TO ALL SNOW AFTER MIDNIGHT. EXPECT ACCUMULATION FRIDAY NIGHT TO BE AROUND A HALF INCH IN ALL BUT THE FAR SOUTHWEST PORTIONS OF THE FORECAST AREA WHERE LITTLE TO NO ACCUMULATION IS EXPECTED. SNOW SHOWERS WILL CONTINUE THROUGH MIDDAY ON SATURDAY WHEN A COLD FRONT PUSHES THROUGH AND A DRY SLOT MOVES ACROSS THE FORECAST AREA. ADDITIONAL ACCUMULATIONS OF LESS THAN A HALF INCH ARE EXPECTED AT THIS TIME ACROSS THE BLUEGRASS REGION OF KY. AS UPPER LOW AND SURFACE LOW MOVE ACROSS NORTH OH AND UP THE EASTERN GREAT LAKES...WRAP AROUND MOISTURE COUPLED WITH NORTHERLY FLOW WILL BRING A CHANCE OF LIGHT SNOW SHOWERS TO AREAS MAINLY EAST OF INTERSTATE 75 ON SATURDAY NIGHT...LITTLE TO NO ADDITIONAL ACCUMULATIONS ARE EXPECTED. TEMPERATURES ON SATURDAY MORNING WILL START OUT IN THE UPPER 20S AND CLIMB TO THE MID 30S. SUNDAY THROUGH TUESDAY... TROUGH AXIS SWINGS THROUGH AND SHIFTS EAST OF THE AREA BY SUNDAY MORNING AND CLEARING SKIES ARE EXPECTED. EXPECT TEMPERATURES TO BE A FEW DEGREES COLDER DESPITE LESS CLOUD COVER AS DEEP TROUGH TO THE EAST AND NORTHERLY FLOW OVER THE REGION ALLOWS COLDER AIR TO SEEP SOUTHWARD. EXPECT HIGHS IN THE LOW TO MID 30S ON SUNDAY. SURFACE HIGH PRESSURE BUILDS OVER THE SOUTHEAST STATES ON MONDAY WITH ZONAL FLOW ALOFT ALLOWING WAA TO SET UP WITH SOUTHERLY SURFACE FLOW. MOSTLY SUNNY SKIES WILL GIVE WAY TO INCREASING CLOUDINESS BY LATE MONDAY AFTERNOON AS ANOTHER WEAK CLIPPER SYSTEM APPROACHES THE AREA FOR TUESDAY. PLENTY OF MOISTURE WILL BEGIN STREAMING INTO THE AREA FROM THE WESTERN GULF COAST OVERNIGHT MONDAY AND SHOWERS WILL BE POSSIBLE BY TUESDAY MIDDAY AS ANOTHER COOL FRONT MAKES ITS WAY THROUGH THE REGION. EXPECT HIGHS ON MONDAY AND TUESDAY IN THE 40S WITH OVERNIGHT LOWS IN THE UPPER 20S TO LOW 30S. && .AVIATION (12Z TAFS)... SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE TO AFFECT LEX AND MAYBE BWG THROUGH 13-14Z THIS MORNING BEFORE ALL RAIN MOVES OFF TO THE EAST. MVFR-IFR CIGS WILL CONTINUE THROUGH ABOUT 18Z FOR BWG AND SDF...MAYBE LONGER AT LEX. UNDER THE CLOUDY SKIES...WINDS OUT OF THE SSW WILL GUST UP TO 25 KTS GENERALLY. IF THE SUN CAN COME OUR OR A FEW CLOUDS CAN CLEAR BY 18Z...THEN GUSTS THIS AFTERNOON COULD REACH 30 KTS OR PERHAPS MORE IN A FEW SPOTS BEFORE A COLD FRONT PASSES THROUGH LATE THIS AFTERNOON. WITH THE COLD FRONTAL PASSAGE...MORE SHRA AND TS COULD FORM ALONG IT BUT THINK THE MAIN THREAT FOR THIS WOULD BE FOR LEX ONLY...AND PERHAPS JUST A FEW SHOWERS WOULD AFFECT SDF OR BWG TO A LESSER EXTENT. WITH THE FROPA...AND THROUGH THE REST OF THE TAF PERIOD...MVFR CIGS SHOULD BE THE RULE FOR LEX...MOSTLY SDF TOO...AND TO A LESSER EXTENT BWG. WINDS WILL VEER AROUND TO THE WNW BEHIND THE FRONT AND WILL BE GUSTY...UP TO 20-25KTS GENERALLY. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ WEATHER.GOV/LOUISVILLE UPDATE...13 SHORT TERM...AL LONG TERM....LMS AVIATION.....AL
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
614 AM EST WED FEB 18 2009 .UPDATE... UPDATED AVIATION DISCUSSION FOR 12Z TAFS. && .SHORT TERM (TODAY AND TONIGHT)... MASS OF WARM-AIR ADVECTION SHOWERS AND STORMS ARE AFFECTING MUCH OF THE SOUTHERN CWA. A FEW STRONG STORMS HAVE FORMED WITHIN THE MASS...PRODUCING PEA SIZE HAIL NEAR BOWLING GREEN. ONE STORM THAT PRODUCED NICKEL HAIL NEAR THE KY/TN BORDER MOVED ACROSS LOGAN AND SIMPSON BUT HAS SINCE WANED. EVERYTHING NOW IS BEHAVING...WITH HEAVY RAINFALL TRAINING OVER THE SAME AREAS...AND LOTS OF LIGHTNING. GUSTY WINDS ARE ALSO OCCURRING...WITH PEAKS AROUND 40-45 MPH. BUT RECENT ACARS SOUNDINGS SHOW NICE CAPPING AT 800MB...SO ANY SEVERE WIND GUSTS MIXING DOWN SHOULD NOT OCCUR. THROUGH SUNRISE...ANY STRONG STORM WILL BE CAPABLE OF PRODUCING PEA AND MARBLE SIZE HAIL. THIS AREA OF SHOWERS AND STORMS IS ALL AHEAD OF AN APPROACHING LOW PRESSURE CENTER OVER NW MISSOURI. THIS LOW WILL PUSH TOWARDS NE INDIANA TODAY...WHICH WILL ALSO PUSH THESE SHOWERS AND STORMS EAST OF THE CWA MOSTLY BY 18Z. THEN THE COLD FRONT FROM THE LOW WILL PASS THROUGH THE CWA BETWEEN ROUGHLY 21Z AND 03Z. THE NMM-WRF HAS A GOOD HANDLE ON CURRENT PRECIP...AND THAT MODEL SHOWS MORE SHOWERS/STORMS DEVELOPING OVER OUR ERN CWA ALONG THE COLD FRONT. ASSUMING THE CAP ALOFT CAN BREAK THIS AFTERNOON...WILL GO WITH THIS MODEL SOLUTION AND HAVE THE HIGHEST POPS OVER THE ERN HALF OF THE CWA. DESPITE CLOUDS AND PRECIP...TEMPS SHOULD CLIMB ESPECIALLY THIS AFTERNOON INTO THE MID 50S N TO THE MID 60S S. WINDS WILL CONTINUE TO BE GUSTY...ESPECIALLY LATER THIS AFTERNOON AHEAD OF THE COLD FRONT...WITH GUSTS UP TO 35 MPH BEING POSSIBLE. TONIGHT...ON THE BACK SIDE OF THE LOW/FRONT...TEMPS SHOULD FALL INTO THE UPPER 20S AND LOW 30S. RESIDUAL WRAP-AROUND MOISTURE WILL AFFECT MAINLY OUR NERN CWA OVERNIGHT...WHERE RAIN WILL CHANGE TO SNOW SHOWERS. THIS WILL MOST LIKELY OCCUR OVER THE NORTHERN BLUEGRASS AFTER MIDNIGHT TOWARDS DAWN THURSDAY. .LONG TERM (THURSDAY THROUGH TUESDAY)... NOT TOO MANY CHANGES REQUIRED THROUGH THE EXTENDED THIS MORNING. MAIN CHALLENGES WILL BE MOVING OUT PRECIPITATION ON THURSDAY AND ANOTHER CLIPPER SYSTEM BRINGING A CHANCE FOR LIGHT ACCUMULATING SNOW ON SATURDAY. A WEAK DISTURBANCE ON TUESDAY NEAR THE END OF THE FORECAST PERIOD COULD ALSO BRING ANOTHER ROUND OF PRECIPITATION. THURSDAY THROUGH SATURDAY... UPPER LEVEL LOW OVER MICHIGAN WILL MOVE EASTWARD INTO UPSTATE NEW YORK PULLING SURFACE LOW INTO THE NORTHEAST U.S. NORTHWEST FLOW ACROSS THE AREA WILL USHER IN HIGH SURFACE PRESSURE AND LINGERING PRECIPITATION SHOULD MOVE EAST OF THE AREA BY MIDDAY WITH SOME FLURRIES POSSIBLE ACROSS NORTH CENTRAL KY AND THE BLUEGRASS REGION IN THE AFTERNOON BEFORE DRIER CONDITIONS SET IN THURSDAY NIGHT AND FRIDAY. WITH HIGHS ONLY TOPPING OUT IN THE LOW 30S ON THURSDAY AND CLEARING SKIES OVERNIGHT TEMPS WILL BOTTOM OUT IN THE TEENS BY FRIDAY MORNING. PLENTY OF SUNSHINE ON FRIDAY AND SOME LOW LEVEL WAA WILL ALLOW TEMPS TO REBOUND INTO THE MID 40S IN THE SOUTHWEST TO THE UPPER 30S IN THE NORTHEAST. CLOUDS WILL INCREASE DURING THE LATE AFTERNOON AND EARLY EVENING ON FRIDAY AS THE NEXT CLIPPER SYSTEM APPROACHES THE AREA LATE FRIDAY NIGHT AND SATURDAY. EXPECT A MIX OF RAIN/SNOW LATE FRIDAY EVENING MAINLY ACROSS AREAS WEST OF INTERSTATE 65 WITH PRECIPITATION SPREADING EASTWARD TOWARD SATURDAY MORNING AND CHANGING TO ALL SNOW AFTER MIDNIGHT. EXPECT ACCUMULATION FRIDAY NIGHT TO BE AROUND A HALF INCH IN ALL BUT THE FAR SOUTHWEST PORTIONS OF THE FORECAST AREA WHERE LITTLE TO NO ACCUMULATION IS EXPECTED. SNOW SHOWERS WILL CONTINUE THROUGH MIDDAY ON SATURDAY WHEN A COLD FRONT PUSHES THROUGH AND A DRY SLOT MOVES ACROSS THE FORECAST AREA. ADDITIONAL ACCUMULATIONS OF LESS THAN A HALF INCH ARE EXPECTED AT THIS TIME ACROSS THE BLUEGRASS REGION OF KY. AS UPPER LOW AND SURFACE LOW MOVE ACROSS NORTH OH AND UP THE EASTERN GREAT LAKES...WRAP AROUND MOISTURE COUPLED WITH NORTHERLY FLOW WILL BRING A CHANCE OF LIGHT SNOW SHOWERS TO AREAS MAINLY EAST OF INTERSTATE 75 ON SATURDAY NIGHT...LITTLE TO NO ADDITIONAL ACCUMULATIONS ARE EXPECTED. TEMPERATURES ON SATURDAY MORNING WILL START OUT IN THE UPPER 20S AND CLIMB TO THE MID 30S. SUNDAY THROUGH TUESDAY... TROUGH AXIS SWINGS THROUGH AND SHIFTS EAST OF THE AREA BY SUNDAY MORNING AND CLEARING SKIES ARE EXPECTED. EXPECT TEMPERATURES TO BE A FEW DEGREES COLDER DESPITE LESS CLOUD COVER AS DEEP TROUGH TO THE EAST AND NORTHERLY FLOW OVER THE REGION ALLOWS COLDER AIR TO SEEP SOUTHWARD. EXPECT HIGHS IN THE LOW TO MID 30S ON SUNDAY. SURFACE HIGH PRESSURE BUILDS OVER THE SOUTHEAST STATES ON MONDAY WITH ZONAL FLOW ALOFT ALLOWING WAA TO SET UP WITH SOUTHERLY SURFACE FLOW. MOSTLY SUNNY SKIES WILL GIVE WAY TO INCREASING CLOUDINESS BY LATE MONDAY AFTERNOON AS ANOTHER WEAK CLIPPER SYSTEM APPROACHES THE AREA FOR TUESDAY. PLENTY OF MOISTURE WILL BEGIN STREAMING INTO THE AREA FROM THE WESTERN GULF COAST OVERNIGHT MONDAY AND SHOWERS WILL BE POSSIBLE BY TUESDAY MIDDAY AS ANOTHER COOL FRONT MAKES ITS WAY THROUGH THE REGION. EXPECT HIGHS ON MONDAY AND TUESDAY IN THE 40S WITH OVERNIGHT LOWS IN THE UPPER 20S TO LOW 30S. && .AVIATION (12Z TAFS)... SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE TO AFFECT LEX AND MAYBE BWG THROUGH 13-14Z THIS MORNING BEFORE ALL RAIN MOVES OFF TO THE EAST. MVFR-IFR CIGS WILL CONTINUE THROUGH ABOUT 18Z FOR BWG AND SDF...MAYBE LONGER AT LEX. UNDER THE CLOUDY SKIES...WINDS OUT OF THE SSW WILL GUST UP TO 25 KTS GENERALLY. IF THE SUN CAN COME OUR OR A FEW CLOUDS CAN CLEAR BY 18Z...THEN GUSTS THIS AFTERNOON COULD REACH 30 KTS OR PERHAPS MORE IN A FEW SPOTS BEFORE A COLD FRONT PASSES THROUGH LATE THIS AFTERNOON. WITH THE COLD FRONTAL PASSAGE...MORE SHRA AND TS COULD FORM ALONG IT BUT THINK THE MAIN THREAT FOR THIS WOULD BE FOR LEX ONLY...AND PERHAPS JUST A FEW SHOWERS WOULD AFFECT SDF OR BWG TO A LESSER EXTENT. WITH THE FROPA...AND THROUGH THE REST OF THE TAF PERIOD...MVFR CIGS SHOULD BE THE RULE FOR LEX...MOSTLY SDF TOO...AND TO A LESSER EXTENT BWG. WINDS WILL VEER AROUND TO THE WNW BEHIND THE FRONT AND WILL BE GUSTY...UP TO 20-25KTS GENERALLY. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ WEATHER.GOV/LOUISVILLE SHORT TERM...AL LONG TERM....LMS AVIATION.....AL
AREA FORECAST DISCUSSION...UPDATED
NWS BLACKSBURG VA
1116 AM EST WED FEB 18 2009 .SYNOPSIS... A WINTER STORM WILL MOVE THROUGH THE GREAT LAKES AND OHIO VALLEY TODAY...WITH ITS ASSOCIATED COLD FRONT PASSING EAST ACROSS THE MID ATLANTIC REGION...SPREADING RAIN AND A BRIEF PERIOD OF WINTRY MIX TO THE REGION. THE COLD FRONT WILL MOVE EAST OF THE AREA TONIGHT AS THE WINTER STORM MOVE INTO NEW ENGLAND. COLDER AND WINDY CONDITIONS WILL DEVELOP BEHIND THE FRONT WITH MOUNTAIN SNOW SHOWERS. && .NEAR TERM /THROUGH TONIGHT/... UPDATE TO REMOVE GOING ADVISORIES AS TEMPS HAVE CLIMBED ABOVE FREEZING IN MOST SPOTS WITH ONLY SPOTTY PRECIP REMAINING. INITIAL FAST MOVING SLUG OF MIXED PRECIP WITH FRONT ALOFT HAS RACED INTO THE FAR NORTHERN/EASTERN PORTIONS OF THE CWA WITH MORE SCATTERED NATURE -RA TO THE WEST. NOSE OF JET ALOFT AND THE ASSOCIATED UPPER DIFFLUENCE LIKELY TO BE THE MAIN PLAYER FOR ADDITIONAL PRECIP THRU THE AFTERNOON...WELL IN ADVANCE OF THE COLD FRONT NEARING THE MISS RIVER. LATEST WRF SHOWS MUCH OF THE ADDED SHRA ACROSS THE WEST WHERE CAN TOTALLY RULE OUT SOME EMBEDDED THUNDER ALONG INSTABILITY AXIS ESPCLY FAR WESTERN SLOPES ON THE PERIMETER OF THE INSITU WEDGE. OTRW PLAN TO LOWER POPS SOME ESPCLY AFTER 18Z WHEN THE LATEST 12Z NAM HAS QUITE A DRY SLOT WORKING IN WITH SOME BREAKS POSSIBLE WEST. NUDGED TEMPS DOWN SOME NW WHERE HOVERING NEAR FREEZING AND OVER CENTRAL ZONES NEAR THE BLUE RIDGE WHERE THE WEDGE IS STRONGER. SINCE ALSO STILL HAVE SOME TEMPS NEAR FREEZING AND AT LEAST SCTD PRECIP IN THE ADVISORY AREAS...PLAN TO LEAVE THE WSW PRODUCTS IN PLACE UNTIL NOON WHEN WILL SEND AN UPDATED ZFP FOR THE AFTERNOON. PREVIOUS DISCUSSION BELOW... REGIONAL RADARS INDICATE A LARGE SWATH OF PRECIPITATION ADVANCING EAST ACROSS TN/KY. THIS PRECIPITATION WILL ARRIVE THIS MORNING AND WILL BE WIDESPREAD FOR AT LEAST THE FIRST HALF OF THE DAY. AT THE ONSET...TEMPERATURES WILL SUPPORT A WINTRY MIX WITH SNOW AND SLEET. THE PROFILE IS PROGGED TO WARM RAPIDLY ALOFT AND THINK JUST ABOUT ALL LOCATIONS IN OUR CWA WILL TURN OVER TO PLAIN OL RAIN BY MID MORNING. FOR THE MOST PART...THE PRECIPITATION WILL BE FALLING INTO A BOUNDARY LAYER THAT IS ABOVE FREEZING...THUS DO NOT ANTICIPATE ANY SIGNIFICANT ACCUMULATION. THE COLDEST LOCATIONS...ALONG AND NORTH OF INTERSTATE 64 MAY EXPERIENCE AN INCH OR TWO OF SNOW AND SLEET...BEFORE CHANGING TO FREEZING RAIN AND THEN RAIN. FOR THIS REASON HAVE ISSUED A WINTER WEATHER ADVISORY THIS MORNING FOR BATH...ROCKBRIDGE...AND AMHERST. HAVE ALSO ISSUED A FREEZING RAIN ADVISORY FOR THE NORTHWEST MOUNTAINS OF NORTH CAROLINA...INCLUDING GRAYSON AND CARROLL COUNTIES IN VIRGINIA WHERE TEMPERATURES ARE AROUND FREEZING. ASIDE FROM THE INSITU COLD AIR THAT IS IN PLACE ACROSS THE CWA...THERE IS NO BLOCKING HIGH TO THE NORTH. APPROACH OF COLD FRONT AND WARM AIR ADVECTION AHEAD OF THIS FEATURE SHOULD ALLOW TEMPS TO STEADILY CLIMB THROUGH THE DAY...MOST AREAS CLIMBING INTO THE 40S. THE SURFACE FRONT IS PROGGED TO PASS THROUGH THE AREA BY MIDNIGHT TONIGHT WITH THE SURFACE LOW MOVING INTO EASTERN ONTARIO. STRONG COLD AIR ADVECTION WILL TAKE PLACE BEHIND THE FRONT AND THIS WILL SET THE STAGE FOR A COLD NEXT COUPLE OF DAYS WITH MOUNTAIN SNOW SHOWERS AND FLURRIES ALONG WITH BRISK NORTHWEST WINDS. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... BIGGEST CONCERN FOR THIS PART OF THE PACKAGE IS WINDS AND UPSLOPE SNOW. DEBATING WHETHER OR NOT TO ISSUE AN ELEVATION WATCH FOR GREENBRIER. HOWEVER...NAM12 H7 MOISTURE IS FARTHER NORTH AND MOISTURE DEPTH IS MORE SHALLOW THAN THE PAST FEW NIGHTS. SEEMS AS THOUGH THE DEEPEST MOISTURE WILL BE AROUND FROM MID MORNING THURS THROUGH EARLY AFTERNOON. ATTM...THE BEST COURSE OF ACTION WOULD BE A SNOW ADVISORY SAY FROM GREENBRIER TO TAZEWELL FROM THURS INTO THURS NIGHT BUT THIS CAN BE FINE TUNED ON FUTURE SHIFTS. ABOVE 2500 FEET IN GREENBRIER MAY BE CLOSE OR JUST ABV WARNING CRITERIA BY FRIDAY MORNING AND THIS CAN BE HANDLED IN AN ADVISORY TOO. ANOTHER ISSUE IS THE WIND WHICH WILL BE BLOWING THE SNOW AROUND. NONETHELESS...IT WILL BE SNOWING HARD AT TIMES WITH WINDS GREATLY REDUCING VISIBILITIES IN THESE SPOTS THURS AND THURS NIGHT. A COUPLE INCHES MAY ALSO FALL IN THE SKI COUNTRY OF NW NC WITH AN INCH OR LESS AT THE LOWER ELEVATIONS. IF WINDS STAY UP...WIND CHILL ADVISORY CRITERIA MAY BE MET INTO FRIDAY MORNING FOR THE EXTREME SW...WHICH WILL RECEIVE THE COLDEST AIR FIRST. CONSIDERING H85 VALUES WILL BE NEAR -15C...SHALLOW ARCTIC AIRMASS...DID KEEP TEMPS A FEW DEGREES BELOW COLDEST GUIDANCE FOR MIN/MAX ON FRIDAY. WILL ALSO NEED A WIND ADVISORY FOR NW NC AND POSSIBLY PART OF THE BLUE RIDGE IN VA THURSDAY AND THURSDAY NIGHT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... TIMING OF THE SATURDAY SYSTEM IS SIMILAR TO YESTERDAY...ALTHOUGH MAY BE SLOWER BY A FEW HOURS. STILL LOOKING AT BEST CHANCE OF PRECIP ARRIVING IN THE WEST DURING THE DAY AND MOVING EAST BY EVENING WITH UPSLOPE SNOW SHOWERS ON THE BACK SIDE LASTING INTO SUNDAY. AFTER THIS THE PATTERN FLATTENS WITH A BACKDOOR FRONT STRETCHING INTO THE MID ATLANTIC BY TUESDAY BUT NO AFFECTS IN TERM OF PRECIP FOR OUR AREA. TEMPS WILL SLOWLY MODERATE AS SFC HIGH SETTLES ACROSS THE AREA SUN-MON. THE 12Z ECMWF MODEL HAS A DIFFERENT SOLUTION INTO MONDAY AS IT FORMS A NEW LOW ALONG THE FRONT IN THE SOUTHEAST SUNDAY MORNING AND SHIFTS IT OFF THE NORTH CAROLINA/VIRGINIA COAST BY 12Z MONDAY. THIS SYSTEM WOULD BRING A GOOD SNOW TO PORTIONS OF THE AREA IF IT PANS OUT...BUT ATTM...THE OTHER MODELS ARE NOT FAVORING IT. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... RADAR RETURNS NOT PRODUCING MUCH AT THE GROUND THIS HOUR...AND WILL PROBABLY BE THE CASE OVER THE NEXT FEW HOURS WITH VERY DRY LLVLS. WOULD THINK THOUGH THERE IS A GOOD CHANCE FOR ICING ALOFT OF AIRCRAFT HOWEVER WITH THIS SETUP. VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING AS HIGH PRESSURE MAINTAINS CONTROL OF OUR AREA. OVERNIGHT...A SYSTEM WILL SWEEP THROUGH THE AREA BRINGING MVFR/IFR CIGS AND MAINLY MVFR VSBYS STARTING BETWEEN 08-12Z FROM WEST TO EAST. ACCOMPANYING THIS CLOUD COVER WILL BE A BRIEF SHOT OF SNOW/SLEET/FZRA BEFORE QUICKLY CHANGING OVER TO ALL RAIN. THE WINTRY MIX WILL LAST LONGEST AT LWB...AND SHORTEST AT BLF. AREAS OF SOUTHEAST WEST VIRGINIA AND PARTS OF SOUTHWEST VIRGINIA ALONG AND NORTH OF A KROA-KLYH LINE CAN EXPECT SNOW OR SLEET AT THE ONSET OF THE PRECIPITATION FOR A FEW HOURS. ELSEWHERE...RAIN IS EXPECTED AT THE ONSET OF THE PRECIPITATION. DURING THE MORNING WEDNESDAY...WARMER AIR ENTERING THE REGION WILL ALLOW FOR A TRANISTION TO ALL RAIN ACROSS THE AREA. THE CIG/VSBY RESTRICTIONS WILL LIKELY CONTINUE THROUGH WEDNESDAY NIGHT UNTIL A COLD FRONT MOVES THROUGH BY THURSDAY MORNING. SCT RAIN AND SNOW SHOWERS WILL CONTINUE IN THE WESTERN MOUNTAINS IN A COLD NORTHWEST FLOW THURSDAY AND FRIDAY. STRONG WINDS CAN BE EXPECTED THURSDAY/THURSDAY NIGHT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/PM NEAR TERM...JH/PM SHORT TERM...KM LONG TERM...WP AVIATION...KM/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1023 AM EST WED FEB 18 2009 .SYNOPSIS... A WINTER STORM WILL MOVE THROUGH THE GREAT LAKES AND OHIO VALLEY TODAY...WITH ITS ASSOCIATED COLD FRONT PASSING EAST ACROSS THE MID ATLANTIC REGION...SPREADING RAIN AND A BRIEF PERIOD OF WINTRY MIX TO THE REGION. THE COLD FRONT WILL MOVE EAST OF THE AREA TONIGHT AS THE WINTER STORM MOVE INTO NEW ENGLAND. COLDER AND WINDY CONDITIONS WILL DEVELOP BEHIND THE FRONT WITH MOUNTAIN SNOW SHOWERS. && .NEAR TERM /THROUGH TONIGHT/... INITIAL FAST MOVING SLUG OF MIXED PRECIP WITH FRONT ALOFT HAS RACED INTO THE FAR NORTHERN/EASTERN PORTIONS OF THE CWA WITH MORE SCATTERED NATURE -RA TO THE WEST. NOSE OF JET ALOFT AND THE ASSOCIATED UPPER DIFFLUENCE LIKELY TO BE THE MAIN PLAYER FOR ADDITIONAL PRECIP THRU THE AFTERNOON...WELL IN ADVANCE OF THE COLD FRONT NEARING THE MISS RIVER. LATEST WRF SHOWS MUCH OF THE ADDED SHRA ACROSS THE WEST WHERE CAN TOTALLY RULE OUT SOME EMBEDDED THUNDER ALONG INSTABILITY AXIS ESPCLY FAR WESTERN SLOPES ON THE PERIMETER OF THE INSITU WEDGE. OTRW PLAN TO LOWER POPS SOME ESPCLY AFTER 18Z WHEN THE LATEST 12Z NAM HAS QUITE A DRY SLOT WORKING IN WITH SOME BREAKS POSSIBLE WEST. NUDGED TEMPS DOWN SOME NW WHERE HOVERING NEAR FREEZING AND OVER CENTRAL ZONES NEAR THE BLUE RIDGE WHERE THE WEDGE IS STRONGER. SINCE ALSO STILL HAVE SOME TEMPS NEAR FREEZING AND AT LEAST SCTD PRECIP IN THE ADVISORY AREAS...PLAN TO LEAVE THE WSW PRODUCTS IN PLACE UNTIL NOON WHEN WILL SEND AN UPDATED ZFP FOR THE AFTERNOON. PREVIOUS DISCUSSION BELOW... REGIONAL RADARS INDICATE A LARGE SWATH OF PRECIPITATION ADVANCING EAST ACROSS TN/KY. THIS PRECIPITATION WILL ARRIVE THIS MORNING AND WILL BE WIDESPREAD FOR AT LEAST THE FIRST HALF OF THE DAY. AT THE ONSET...TEMPERATURES WILL SUPPORT A WINTRY MIX WITH SNOW AND SLEET. THE PROFILE IS PROGGED TO WARM RAPIDLY ALOFT AND THINK JUST ABOUT ALL LOCATIONS IN OUR CWA WILL TURN OVER TO PLAIN OL RAIN BY MID MORNING. FOR THE MOST PART...THE PRECIPITATION WILL BE FALLING INTO A BOUNDARY LAYER THAT IS ABOVE FREEZING...THUS DO NOT ANTICIPATE ANY SIGNIFICANT ACCUMULATION. THE COLDEST LOCATIONS...ALONG AND NORTH OF INTERSTATE 64 MAY EXPERIENCE AN INCH OR TWO OF SNOW AND SLEET...BEFORE CHANGING TO FREEZING RAIN AND THEN RAIN. FOR THIS REASON HAVE ISSUED A WINTER WEATHER ADVISORY THIS MORNING FOR BATH...ROCKBRIDGE...AND AMHERST. HAVE ALSO ISSUED A FREEZING RAIN ADVISORY FOR THE NORTHWEST MOUNTAINS OF NORTH CAROLINA...INCLUDING GRAYSON AND CARROLL COUNTIES IN VIRGINIA WHERE TEMPERATURES ARE AROUND FREEZING. ASIDE FROM THE INSITU COLD AIR THAT IS IN PLACE ACROSS THE CWA...THERE IS NO BLOCKING HIGH TO THE NORTH. APPROACH OF COLD FRONT AND WARM AIR ADVECTION AHEAD OF THIS FEATURE SHOULD ALLOW TEMPS TO STEADILY CLIMB THROUGH THE DAY...MOST AREAS CLIMBING INTO THE 40S. THE SURFACE FRONT IS PROGGED TO PASS THROUGH THE AREA BY MIDNIGHT TONIGHT WITH THE SURFACE LOW MOVING INTO EASTERN ONTARIO. STRONG COLD AIR ADVECTION WILL TAKE PLACE BEHIND THE FRONT AND THIS WILL SET THE STAGE FOR A COLD NEXT COUPLE OF DAYS WITH MOUNTAIN SNOW SHOWERS AND FLURRIES ALONG WITH BRISK NORTHWEST WINDS. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... BIGGEST CONCERN FOR THIS PART OF THE PACKAGE IS WINDS AND UPSLOPE SNOW. DEBATING WHETHER OR NOT TO ISSUE AN ELEVATION WATCH FOR GREENBRIER. HOWEVER...NAM12 H7 MOISTURE IS FARTHER NORTH AND MOISTURE DEPTH IS MORE SHALLOW THAN THE PAST FEW NIGHTS. SEEMS AS THOUGH THE DEEPEST MOISTURE WILL BE AROUND FROM MID MORNING THURS THROUGH EARLY AFTERNOON. ATTM...THE BEST COURSE OF ACTION WOULD BE A SNOW ADVISORY SAY FROM GREENBRIER TO TAZEWELL FROM THURS INTO THURS NIGHT BUT THIS CAN BE FINE TUNED ON FUTURE SHIFTS. ABOVE 2500 FEET IN GREENBRIER MAY BE CLOSE OR JUST ABV WARNING CRITERIA BY FRIDAY MORNING AND THIS CAN BE HANDLED IN AN ADVISORY TOO. ANOTHER ISSUE IS THE WIND WHICH WILL BE BLOWING THE SNOW AROUND. NONETHELESS...IT WILL BE SNOWING HARD AT TIMES WITH WINDS GREATLY REDUCING VISIBILITIES IN THESE SPOTS THURS AND THURS NIGHT. A COUPLE INCHES MAY ALSO FALL IN THE SKI COUNTRY OF NW NC WITH AN INCH OR LESS AT THE LOWER ELEVATIONS. IF WINDS STAY UP...WIND CHILL ADVISORY CRITERIA MAY BE MET INTO FRIDAY MORNING FOR THE EXTREME SW...WHICH WILL RECEIVE THE COLDEST AIR FIRST. CONSIDERING H85 VALUES WILL BE NEAR -15C...SHALLOW ARCTIC AIRMASS...DID KEEP TEMPS A FEW DEGREES BELOW COLDEST GUIDANCE FOR MIN/MAX ON FRIDAY. WILL ALSO NEED A WIND ADVISORY FOR NW NC AND POSSIBLY PART OF THE BLUE RIDGE IN VA THURSDAY AND THURSDAY NIGHT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... TIMING OF THE SATURDAY SYSTEM IS SIMILAR TO YESTERDAY...ALTHOUGH MAY BE SLOWER BY A FEW HOURS. STILL LOOKING AT BEST CHANCE OF PRECIP ARRIVING IN THE WEST DURING THE DAY AND MOVING EAST BY EVENING WITH UPSLOPE SNOW SHOWERS ON THE BACK SIDE LASTING INTO SUNDAY. AFTER THIS THE PATTERN FLATTENS WITH A BACKDOOR FRONT STRETCHING INTO THE MID ATLANTIC BY TUESDAY BUT NO AFFECTS IN TERM OF PRECIP FOR OUR AREA. TEMPS WILL SLOWLY MODERATE AS SFC HIGH SETTLES ACROSS THE AREA SUN-MON. THE 12Z ECMWF MODEL HAS A DIFFERENT SOLUTION INTO MONDAY AS IT FORMS A NEW LOW ALONG THE FRONT IN THE SOUTHEAST SUNDAY MORNING AND SHIFTS IT OFF THE NORTH CAROLINA/VIRGINIA COAST BY 12Z MONDAY. THIS SYSTEM WOULD BRING A GOOD SNOW TO PORTIONS OF THE AREA IF IT PANS OUT...BUT ATTM...THE OTHER MODELS ARE NOT FAVORING IT. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... RADAR RETURNS NOT PRODUCING MUCH AT THE GROUND THIS HOUR...AND WILL PROBABLY BE THE CASE OVER THE NEXT FEW HOURS WITH VERY DRY LLVLS. WOULD THINK THOUGH THERE IS A GOOD CHANCE FOR ICING ALOFT OF AIRCRAFT HOWEVER WITH THIS SETUP. VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING AS HIGH PRESSURE MAINTAINS CONTROL OF OUR AREA. OVERNIGHT...A SYSTEM WILL SWEEP THROUGH THE AREA BRINGING MVFR/IFR CIGS AND MAINLY MVFR VSBYS STARTING BETWEEN 08-12Z FROM WEST TO EAST. ACCOMPANYING THIS CLOUD COVER WILL BE A BRIEF SHOT OF SNOW/SLEET/FZRA BEFORE QUICKLY CHANGING OVER TO ALL RAIN. THE WINTRY MIX WILL LAST LONGEST AT LWB...AND SHORTEST AT BLF. AREAS OF SOUTHEAST WEST VIRGINIA AND PARTS OF SOUTHWEST VIRGINIA ALONG AND NORTH OF A KROA-KLYH LINE CAN EXPECT SNOW OR SLEET AT THE ONSET OF THE PRECIPITATION FOR A FEW HOURS. ELSEWHERE...RAIN IS EXPECTED AT THE ONSET OF THE PRECIPITATION. DURING THE MORNING WEDNESDAY...WARMER AIR ENTERING THE REGION WILL ALLOW FOR A TRANISTION TO ALL RAIN ACROSS THE AREA. THE CIG/VSBY RESTRICTIONS WILL LIKELY CONTINUE THROUGH WEDNESDAY NIGHT UNTIL A COLD FRONT MOVES THROUGH BY THURSDAY MORNING. SCT RAIN AND SNOW SHOWERS WILL CONTINUE IN THE WESTERN MOUNTAINS IN A COLD NORTHWEST FLOW THURSDAY AND FRIDAY. STRONG WINDS CAN BE EXPECTED THURSDAY/THURSDAY NIGHT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR VAZ015-016. WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VAZ020-024- 035. NC...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NCZ001-002-018. WV...NONE. && $$ SYNOPSIS...JH/PM NEAR TERM...JH/PM SHORT TERM...KM LONG TERM...WP AVIATION...KM/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
552 AM EST WED FEB 18 2009 .SYNOPSIS... A WINTER STORM WILL MOVE THROUGH THE GREAT LAKES AND OHIO VALLEY TODAY. ITS ASSOCIATED COLD FRONT WILL MOVE EAST ACROSS THE MID ATLANTIC REGION...SPREADING RAIN AND A BRIEF PERIOD OF WINTRY MIX TO THE MID ATLANTIC REGION. THE COLD FRONT WILL MOVE EAST OF THE AREA TONIGHT AS THE WINTER STORM MOVE INTO NEW ENGLAND. COLDER AND WINDY CONDITIONS WILL DEVELOP BEHIND THE FRONT WITH MOUNTAIN SNOW SHOWERS. && .NEAR TERM /THROUGH TONIGHT/... REGIONAL RADARS INDICATE A LARGE SWATH OF PRECIPITATION ADVANCING EAST ACROSS TN/KY. THIS PRECIPITATION WILL ARRIVE THIS MORNING AND WILL BE WIDESPREAD FOR AT LEAST THE FIRST HALF OF THE DAY. AT THE ONSET...TEMPERATURES WILL SUPPORT A WINTRY MIX WITH SNOW AND SLEET. THE PROFILE IS PROGGED TO WARM RAPIDLY ALOFT AND THINK JUST ABOUT ALL LOCATIONS IN OUR CWA WILL TURN OVER TO PLAIN OL RAIN BY MID MORNING. FOR THE MOST PART...THE PRECIPITATION WILL BE FALLING INTO A BOUNDARY LAYER THAT IS ABOVE FREEZING...THUS DO NOT ANTICIPATE ANY SIGNIFICANT ACCUMULATION. THE COLDEST LOCATIONS...ALONG AND NORTH OF INTERSTATE 64 MAY EXPERIENCE AN INCH OR TWO OF SNOW AND SLEET...BEFORE CHANGING TO FREEZING RAIN AND THEN RAIN. FOR THIS REASON HAVE ISSUED A WINTER WEATHER ADVISORY THIS MORNING FOR BATH...ROCKBRIDGE...AND AMHERST. HAVE ALSO ISSUED A FREEZING RAIN ADVISORY FOR THE NORTHWEST MOUNTAINS OF NORTH CAROLINA...INCLUDING GRAYSON AND CARROLL COUNTIES IN VIRGINIA WHERE TEMPERATURES ARE AROUND FREEZING. ASIDE FROM THE INSITU COLD AIR THAT IS IN PLACE ACROSS THE CWA...THERE IS NO BLOCKING HIGH TO THE NORTH. APPROACH OF COLD FRONT AND WARM AIR ADVECTION AHEAD OF THIS FEATURE SHOULD ALLOW TEMPS TO STEADILY CLIMB THROUGH THE DAY...MOST AREAS CLIMBING INTO THE 40S. THE SURFACE FRONT IS PROGGED TO PASS THROUGH THE AREA BY MIDNIGHT TONIGHT WITH THE SURFACE LOW MOVING INTO EASTERN ONTARIO. STRONG COLD AIR ADVECTION WILL TAKE PLACE BEHIND THE FRONT AND THIS WILL SET THE STAGE FOR A COLD NEXT COUPLE OF DAYS WITH MOUNTAIN SNOW SHOWERS AND FLURRIES ALONG WITH BRISK NORTHWEST WINDS. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... BIGGEST CONCERN FOR THIS PART OF THE PACKAGE IS WINDS AND UPSLOPE SNOW. DEBATING WHETHER OR NOT TO ISSUE AN ELEVATION WATCH FOR GREENBRIER. HOWEVER...NAM12 H7 MOISTURE IS FARTHER NORTH AND MOISTURE DEPTH IS MORE SHALLOW THAN THE PAST FEW NIGHTS. SEEMS AS THOUGH THE DEEPEST MOISTURE WILL BE AROUND FROM MID MORNING THURS THROUGH EARLY AFTERNOON. ATTM...THE BEST COURSE OF ACTION WOULD BE A SNOW ADVISORY SAY FROM GREENBRIER TO TAZEWELL FROM THURS INTO THURS NIGHT BUT THIS CAN BE FINE TUNED ON FUTURE SHIFTS. ABOVE 2500 FEET IN GREENBRIER MAY BE CLOSE OR JUST ABV WARNING CRITERIA BY FRIDAY MORNING AND THIS CAN BE HANDLED IN AN ADVISORY TOO. ANOTHER ISSUE IS THE WIND WHICH WILL BE BLOWING THE SNOW AROUND. NONETHELESS...IT WILL BE SNOWING HARD AT TIMES WITH WINDS GREATLY REDUCING VISIBILITIES IN THESE SPOTS THURS AND THURS NIGHT. A COUPLE INCHES MAY ALSO FALL IN THE SKI COUNTRY OF NW NC WITH AN INCH OR LESS AT THE LOWER ELEVATIONS. IF WINDS STAY UP...WIND CHILL ADVISORY CRITERIA MAY BE MET INTO FRIDAY MORNING FOR THE EXTREME SW...WHICH WILL RECEIVE THE COLDEST AIR FIRST. CONSIDERING H85 VALUES WILL BE NEAR -15C...SHALLOW ARCTIC AIRMASS...DID KEEP TEMPS A FEW DEGREES BELOW COLDEST GUIDANCE FOR MIN/MAX ON FRIDAY. WILL ALSO NEED A WIND ADVISORY FOR NW NC AND POSSIBLY PART OF THE BLUE RIDGE IN VA THURSDAY AND THURSDAY NIGHT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... TIMING OF THE SATURDAY SYSTEM IS SIMILAR TO YESTERDAY...ALTHOUGH MAY BE SLOWER BY A FEW HOURS. STILL LOOKING AT BEST CHANCE OF PRECIP ARRIVING IN THE WEST DURING THE DAY AND MOVING EAST BY EVENING WITH UPSLOPE SNOW SHOWERS ON THE BACK SIDE LASTING INTO SUNDAY. AFTER THIS THE PATTERN FLATTENS WITH A BACKDOOR FRONT STRETCHING INTO THE MID ATLANTIC BY TUESDAY BUT NO AFFECTS IN TERM OF PRECIP FOR OUR AREA. TEMPS WILL SLOWLY MODERATE AS SFC HIGH SETTLES ACROSS THE AREA SUN-MON. THE 12Z ECMWF MODEL HAS A DIFFERENT SOLUTION INTO MONDAY AS IT FORMS A NEW LOW ALONG THE FRONT IN THE SOUTHEAST SUNDAY MORNING AND SHIFTS IT OFF THE NORTH CAROLINA/VIRGINIA COAST BY 12Z MONDAY. THIS SYSTEM WOULD BRING A GOOD SNOW TO PORTIONS OF THE AREA IF IT PANS OUT...BUT ATTM...THE OTHER MODELS ARE NOT FAVORING IT. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... RADAR RETURNS NOT PRODUCING MUCH AT THE GROUND THIS HOUR...AND WILL PROBABLY BE THE CASE OVER THE NEXT FEW HOURS WITH VERY DRY LLVLS. WOULD THINK THOUGH THERE IS A GOOD CHANCE FOR ICING ALOFT OF AIRCRAFT HOWEVER WITH THIS SETUP. VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING AS HIGH PRESSURE MAINTAINS CONTROL OF OUR AREA. OVERNIGHT...A SYSTEM WILL SWEEP THROUGH THE AREA BRINGING MVFR/IFR CIGS AND MAINLY MVFR VSBYS STARTING BETWEEN 08-12Z FROM WEST TO EAST. ACCOMPANYING THIS CLOUD COVER WILL BE A BRIEF SHOT OF SNOW/SLEET/FZRA BEFORE QUICKLY CHANGING OVER TO ALL RAIN. THE WINTRY MIX WILL LAST LONGEST AT LWB...AND SHORTEST AT BLF. AREAS OF SOUTHEAST WEST VIRGINIA AND PARTS OF SOUTHWEST VIRGINIA ALONG AND NORTH OF A KROA-KLYH LINE CAN EXPECT SNOW OR SLEET AT THE ONSET OF THE PRECIPITATION FOR A FEW HOURS. ELSEWHERE...RAIN IS EXPECTED AT THE ONSET OF THE PRECIPITATION. DURING THE MORNING WEDNESDAY...WARMER AIR ENTERING THE REGION WILL ALLOW FOR A TRANISTION TO ALL RAIN ACROSS THE AREA. THE CIG/VSBY RESTRICTIONS WILL LIKELY CONTINUE THROUGH WEDNESDAY NIGHT UNTIL A COLD FRONT MOVES THROUGH BY THURSDAY MORNING. SCT RAIN AND SNOW SHOWERS WILL CONTINUE IN THE WESTERN MOUNTAINS IN A COLD NORTHWEST FLOW THURSDAY AND FRIDAY. STRONG WINDS CAN BE EXPECTED THURSDAY/THURSDAY NIGHT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR VAZ015-016. WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VAZ020-024- 035. NC...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NCZ001-002-018. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...PM SHORT TERM...KM LONG TERM...WP AVIATION...KM/WP