FXUS61 KRLX 011046
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
534 AM EST TUE DEC 1 2009
.SYNOPSIS...
HIGH PRESSURE TODAY. LOW PRESSURE PASSES THURSDAY MORNING...FOLLOWED
BY COLDER WEATHER THURSDAY NIGHT AND FRIDAY. THE WEEKEND BRINGS A
WEAK DISTURBANCE FOLLOWED BY A HIGH PRESSURE.
&&
.NEAR TERM /THROUGH TONIGHT/...
NORTHWEST FLOW ALOFT WILL FLATTEN OUT AND BECOME MORE ZONAL ON THE
PERIPHERY OF A SOUTHERN STREAM RIDGE AS IT PASSES TO THE SOUTH.
TOWARDS THE END OF THE NEAR TERM...FLOW BECOMES SHARPLY
SOUTHWESTERLY WITH A STRONG UPPER LEVEL SYSTEM CURRENTLY AFFECTING
THE SOUTH PLAINS PUSHING EAST TO THE LOWER MISSISSIPPI VALLEY. AT
THE SURFACE...HIGH PRESSURE CENTERED SOUTH OF THE I-64 CORRIDOR WILL
PASS EAST OFF THE VIRGINIA/NORTH CAROLINA COAST AS THE
AFOREMENTIONED UPPER LEVEL APPROACHES. VARIOUS VORTICITY MAXIMA WILL
ARRIVE IN THE SOUTHWEST VIRGINIA COUNTIES JUST PRIOR TO 12Z
WEDNESDAY...WHEN THE FIRST OF THE SLIGHT CHANCE POPS RETURN TO THE
GRIDS.
THIS WILL BE CASE OF MOISTENING FROM THE TOP DOWN...SO COULD SEE
SOME RADAR RETURNS AT FIRST THAT DO NOT QUITE MAKE IT TO THE
SURFACE...AND PRIMING WILL BE REQUIRED IN THE DRIER AIR IN THE LOW
LEVELS. THIS ADDS A BIT OF DIFFICULTY TO PINPOINTING THE TIMING OF
THE RAIN IN THE SOUTHERN ZONES DESPITE THE PRESENCE OF FORCING.
GUIDANCE NUMBERS DO NOT HAVE MUCH SPREAD FOR MAX TEMPERATURES
TODAY...SO HAVE NOT STRAYED FAR FROM THEM GIVEN A RELATIVELY
BAROTROPIC SCENARIO AND NOT MUCH TO DEAL WITH IN TERMS OF CLOUD
COVER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
THE NAM AND ECMWF SHOW SIMILAR SOLUTIONS ON THE POTENT SOUTHERN
STREAM LOW PRESSURE SYSTEM TRACKING NORTHEASTWARD FROM THE SOUTHERN
PLAINS...INTO THE OHIO VALLEY WEDNESDAY...WITH A COLD FRONT PUSHING
EAST ACROSS THE AREA WEDNESDAY NIGHT. WHILE THE GEM/GFS H5 WAVE AND
ASSOCIATED VORT MAX LOOK FURTHER EAST...THE NAM AND SREF SHOW A MORE
CONSISTENT SOLUTIONS AND ARE RECOMMENDED. KEPT CATEGORICAL POPS WED
AND WED NIGHT ACROSS THE ENTIRE AREA...BUT ADJUSTED THEM FOLLOWING
DETAILS FROM THE NAM/SREF SOLNS. CATEGORICAL POPS REMAIN ALONG
ELEVATIONS OF 3KFT AND HIGHER ON THURSDAY AS WEST TO NORTHWEST FLOW
PUSHES MOISTURE FROM LAKE MICHIGAN INTO OUR NORTHEAST MOUNTAINS
UNDER STRONG COLD ADVECTION...ALLOWING UPSLOPE SNOW TO DEVELOP. MOST
OF THE PRECIP THURSDAY WILL BE RAIN SHOWERS...CHANGING TO SNOW
SHOWERS HIGHER ELEVATIONS OF THE NORTHERN MOUNTAINS THURSDAY
AFTERNOON...BUT WITH LITTLE SNOW ACCUMULATION. LOW LEVEL COLD AIR
FINALLY COMES IN THURSDAY NIGHT...WITH RAIN SHOWERS CHANGING TO SNOW
SHOWERS THURSDAY NIGHT EVERYWHERE...BUT MOST OF THE ACTIVITY WILL BE
IN MOUNTAIN UPSLOPE AREAS...BRINGING LIGHT SNOW ACCUMULATIONS TO THE
MOUNTAINS BY FRIDAY MORNING. THEREFORE...KEPT POPS ACROSS THE
NORTHEAST MOUNTAINS THU NIGHT AND FRI...AND REMOVED THEM COMPLETELY
ACROSS THE LOWLANDS.
THE PREFERRED SOLUTIONS HAVE SHOWN A SLIGHT DECREASE IN THE H8 JET
AHEAD OF THE FRONT IN THEIR LAST RUNS FROM 70 TO AROUND 50 KNOTS.
HOWEVER...STRONG WIND GUSTS ARE STILL EXPECTED AS BUFKIT INDICATES
MOMENTUM TRANSFER OF NEAR 35 KNOTS WED AND WED NIGHT. THE NAM
ISENTROPIC SFC SHOWS DOWNGLIDE DYNAMICS MORE LIKELY TO AFFECT THE
HIGHER ELEVATIONS...AND IN LESS EXTENT THE LOWLANDS.
THEREFORE...INCREASE WIND GUSTS ONCE AGAIN. A WIND ADVISORY MAY BE
REQUIRED WED AND WED NIGHT.
GENERALLY WENT WITH THE SREF/GMOS COMPROMISE FOR TEMPERATURES
THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
MODELS DIFFER IN TIMING OF SYSTEMS THROUGH THE PERIOD.
NORTHWESTERLY FLOW TURNS MORE WESTERLY ON FRIDAY AND ANY SNOW
SHOWER ACTIVITY WILL GRADUALLY DIMINISH...EXCEPT FOR THE EASTERN
MOUNTAINS OF WV. COLDEST TEMPERATURES OF THE SEASON SO FAR ARE ON
TAP AS 85H TEMPS OF -7 TO -12 MOVE IN DURING THE DAY ON FRIDAY.
UNCERTAINTY IN THE TIMING OF FORECAST SYSTEMS..AS GFS BRINGS
ANOTHER SHORT WAVE AROUND THE MEAN TROF AND OVER THE REGION ON
FRIDAY NIGHT AND SATURDAY. HOWEVER ECMWF IS SLOWER BUT STILL HAS
SAME WAVE MOVING THROUGH ON SATURDAY. ONLY KEPT SLIGHT CHC POPS IN
DUE TO UNCERTAINTY. TEMPS WILL HOVER AROUND FREEZING IN THE
LOWLANDS AND 20S IN THE HIGHER ELEVATIONS OF THE EASTERN
MOUNTAINS..AS 85H TEMPS -13 TO -14 RANGE.
MODELS BRING IN HIGH PRESSURE FOR SUNDAY AND MONDAY WITH
TEMPERATURES MODERATING BACK INTO THE 30S AND LOWER 40S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
PATCHY RIVER VALLEY FOG DISSIPATES SHORTLY AFTER SUNRISE...AND VFR
EXPECTED THROUGH THE DAY. HIGH LEVEL CLOUDS ADVECT IN TONIGHT WITH A
SYSTEM APPROACHING FROM THE SOUTHWEST. SURFACE WINDS GENERALLY
SOUTHWEST AND LESS THAN 10KTS.
AFTER 12Z WEDNESDAY...
IFR POSSIBLE IN RAIN WEDNESDAY AFTERNOON AND NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...26/ARJ
NEAR TERM...26
SHORT TERM...ARJ
LONG TERM...JS
AVIATION...26
