FXUS61 KRLX 302028
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
315 PM EST MON NOV 30 2009
.SYNOPSIS...
PRECIPITATION AND FRONT MOVE EAST. HIGH PRESSURE RETURNS LATER
TONIGHT AND TUESDAY. LOW PRESSURE PASSES THURSDAY MORNING. COLDER
THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
SURFACE PRECIPITATION AND FRONT MOVING EAST WITH CONSISTENCY IN THE
MODELS. UPPER TROUGH WILL MOVE ACROSS THE FORECAST AREA BY AROUND
06Z. POSITION OF HIGH BUILDING INTO THE REGION AND MORE WESTERLY
ORIENTATION OF UPPER FLOW WILL MEAN CLEARING RATHER THEN THE NORMAL
WINTER NORTHWEST FLOW CLOUDINESS. AS COLD AIR COMES IN THE RAIN WILL
BRIEFLY SWITCH TO SNOW SHOWERS IN THE MOUNTAINS BEFORE SWITCHING
OVER BUT ANY ACCUMULATIONS WILL BE LIGHT IN THE HIGHER ELEVATIONS.
HIGH WILL MEAN CLEAR SKIES FOR TUESDAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
MODELS IN REASONABLE AGREEMENT ON POTENT SOUTHERN STREAM LOW
PRESSURE SYSTEM TRACKING NORTHEASTWARD FROM THE SOUTHERN PLAINS
TUESDAY...THRU THE OHIO VALLEY WEDNESDAY...AND INTO THE EASTERN
GREAT LAKES BY THURSDAY MORNING. THE RAPID PACE OF EVENTS WILL LEAD
TO A TRANQUIL TUESDAY NIGHT...FOLLOWED BY RAIN RAPIDLY OVERSPREADING
THE AREA WEDNESDAY. THIS SYSTEM TAKES ON A NEGATIVE AS IT LIFTS THRU
THE OHIO VALLEY...THANKS TO A DEEP UPPER TROUGH FORMING OVER THE
MISSISSIPPI VALLEY BY THURSDAY.
THIS SCENARIO RESULTS IN CATEGORY POPS ENTIRE AREA WEDNESDAY...EVEN THOUGH
THERE WILL BE A SHADOW MIN OF QPF BETWEEN THE OHIO RIVER AND THE
MOUNTAINS DUE TO BRISK DOWNSLOPING LOW LEVEL SOUTHEASTERLY FLOW.
LOOK FOR GUSTY SOUTHEAST WINDS ON RIDGETOPS LATER WEDNESDAY.
STILL...GOOD INFLUX OF MOISTURE FROM BOTH THE GULF AND
ATLANTIC...COMBINING WITH GOOD UPPER DYNAMICS...WILL STILL LIKELY
RESULT IN A QUARTER TO HALF AN INCH OF RAIN FOR THE SHADOW AREAS...AND
HIGHER ELSEWHERE. LOOK FOR ABOVE NORMAL TEMPS IN THE 50S WEDNESDAY.
THE LOW LIFTS NORTH AND WEST OF THE AREA WEDNESDAY NIGHT...PUSHING
THE FRONTAL SYSTEM RAPIDLY THRU THE AREA. DEEP CYCLONIC AND MOIST
FLOW AROUND THE DEPARTING SYSTEM WILL BRING AT LEAST SCATTERED
SHOWERS THRU THURSDAY AND THURSDAY NIGHT. WHILE STRONG COLD
ADVECTION ALOFT IS NOTED BEHIND THE FRONT...THE BOUNDARY LAYER WILL
BE SLOWER TO COOL. THUS...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.
MODELS HINT AT A WEAK MID LEVEL WAVE LIFTING OUT AHEAD OF THE MAIN
UPPER TROUGH THURSDAY NIGHT...AFFECTING THE MOUNTAINS WITH SOME
GENERAL LIGHT SNOW. WILL DISMISS THIS FOR NOW AND CONCENTRATE ON
NORTHWEST FLOW TYPE PRECIP.
&&
.LONG TERM /FRIDAY 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 SLGHT 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 /20Z MONDAY THROUGH SATURDAY/...
MVFR CONDITIONS WITH POST FRONTAL MOISTURE INTO THIS EVENING. LOCAL
IFR IN SHOWERS. AFTER UPPER TROUGH PASSES EAST OF FORECAST AREA
DURING THE NIGHT AND HIGH PRESSURE BUILDS INTO THE REGION FROM THE
SOUTHWEST...CONDITIONS WILL IMPROVE TO VFR REMAINING THAT WAY
TUESDAY.
AFTER 18Z TUESDAY...
IFR POSSIBLE IN RAIN WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...AAR/JS/JMV
NEAR TERM...AAR
SHORT TERM...JMV
LONG TERM...JS
AVIATION...AAR
