FXUS61 KRLX 272354
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
655 PM EST FRI NOV 27 2009
.SYNOPSIS...
COLD NORTHWEST FLOW SNOW SHOWERS WILL WIND DOWN OVERNIGHT. HIGH 
PRESSURE RETURNS FOR THIS WEEKEND.  A COLD FRONT BRINGS RAIN MONDAY. 
A LOW PRESSURE SYSTEM BRINGS MORE RAIN WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
VORT LOBE HAS ROTATED OUT OF CWA...AND REMAINING SNOW SHOWERS ARE 
BEING DRIVEN PURELY BY NW FLOW.  ACCUMULATIONS ARE BASICALLY NIL IN 
THE LOWLANDS...AN INCH OR TWO IN THE MOUNTAINOUS COUNTIES...AND 3-4 
INCHES AT THE HIGHEST PEAKS SUCH AS SNOWSHOE.  H850 THERMAL TROUGH 
DOES NOT PULL OUT OF MOUNTAINS UNTIL 06Z TONIGHT OR SO.  HAVE 
CATEGORICAL POPS ALONG THE NW SLOPES TO START...WANING TO CHANCE BY 
THAT THERMAL TROUGH PULLOUT.  ANOTHER INCH OR TWO POSSIBLE HIGH 
UP...SAY ABOVE 2500 FEET...WITH LESS THAN AN INCH ELSEWHERE AT MOST. 
WEST OF THE MOUNTAINS...MOISTURE THINNING SHOULD LEAD TO A SLOW 
DECREASE IN CLOUD COVER.  EXPECTING MAINLY CLEAR SKIES BY 12Z WEST 
OF THE MOUNTAINS.
EXPECT SNOW TO CEASE BY 12Z SATURDAY.  HIGH PRESSURE NOSES IN FROM 
THE SOUTH AND SOUTHWEST TO PROVIDE PLENTY OF SUNSHINE DURING THE 
DAY.  FORESEE A SILENT WARM FRONTAL PASSAGE DURING THE DAY...WITH 
H850 TEMPS REBOUNDING BACK TO +6/+8C BY 21Z.  THIS WILL ALLOW HIGH 
TEMPS TO REBOUND BACK TOWARDS SEASONABLE LEVELS.
RAN WITH A GENERAL MET/MAV BLEND FOR LOWS TONIGHT.  LIKED A TWEAKED 
BIAS-CORRECTED SREF GRID FOR SATURDAY HIGHS...AGAIN AS A GOOD MOS 
COMPROMISE.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
FIRST HALF OF THE SHORT TERM WILL CONTINUE TO REMAIN DRY UNDER THE 
INFLUENCE OF HIGH PRESSURE AT THE SURFACE AND ALOFT. SATURDAY NIGHT 
STILL LOOKS TO BE A NIGHT OF GOOD RADIATIONAL COOLING...ALTHOUGH 
HIGH CLOUDS WILL BEGIN TO INCREASE IN ADVANCE OF THE NEXT SYSTEM. 
SUNDAY WILL BE THE WARMEST DAY OF THE EXTENDED DESPITE AN INCREASE 
IN CLOUD COVER THROUGHOUT THE DAY...AS SOUTHERLY FLOW INCREASES IN 
ADVANCE OF AN APPROACHING COLD FRONT. THIS COLD FRONT...AND 
ASSOCIATED PRECIPITATION WILL BEGIN TO MOVE INTO THE WESTERN EDGE OF 
THE CWA AROUND 06Z...AND EXIT THE CWA AROUND 18Z...WITH MUCH OF THE 
PRECIPITATION BEGINNING TO TAPER OFF BEHIND THE FRONT AS DRIER AIR 
MOVES INTO THE REGION. MUCH COOLER AIR WILL ALSO MOVE INTO THE CWA 
BEHIND THE FRONT...WITH MODEL SOUNDINGS AND THICKNESSES SUGGESTING 
PRECIPITATION TURNING TO SNOW OR A RAIN/SNOW MIX OVER THE HIGHER 
ELEVATIONS BY MONDAY EVENING. ANY ACCUMULATIONS THAT DO OCCUR WILL 
BE LIGHT AS THE GROUND SHOULD STILL BE RELATIVELY WARM...AND DUE TO 
THE OVERALL DECREASE IN MOISTURE BEHIND THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
HAVE TRIMMED BACK SCATTERED POST FRONTAL RAIN AND SNOW SHOWERS TO 
MAINLY MOUNTAINS MONDAY NIGHT...AS ALL MODEL GUIDANCE IS MORE 
PROGRESSIVE. ANY SNOW ACCUMULATION WILL BE VERY LIGHT AND MAINLY 
ABOVE 2000 FEET BEFORE ENDING BY 12Z TUESDAY. HIGH PRESSURE THEN 
BUILDS IN FOR TUESDAY WITH DRY AND COOL CONDITIONS.
THE NEXT BIG ISSUE CONCERNS THE FUTURE OF THE SOUTHERN STREAM UPPER 
LOW THAT WILL HAVE BEEN LEFT BEHIND OVER THE SOUTHWESTERN U.S. EARLY 
NEXT WEEK. THE TRACK AND SPEED OF THIS RATHER POTENT SYSTEM DEPENDS 
ON THE NEXT NORTHERN STREAM SHORT WAVE DIVING OVER THE WEST COAST 
UPPER RIDGE. THE MAJORITY OF OPERATIONAL AND ENSEMBLE GUIDANCE HAS 
THIS ENERGY DIVING INTO THE PLAINS AND AMPLIFYING INTO A DEEP UPPER 
TROUGH OVER THE CENTER OF THE NATION BY THURSDAY. THIS ACCEPTED 
SCENARIO LIFTS THE SOUTHERN STREAM LOW PRESSURE SYSTEM NORTHEASTWARD 
THROUGH THE OHIO VALLEY WEDNESDAY AND THURSDAY. THE OPERATIONAL 
ECMWF WAS USED FOR DETAILS IN THIS ACCEPTED SCENARIO. THE GFS 
CONTINUES TO BE AN OUTLIER IN PROGRESSING THE NORTHERN STREAM SYSTEM 
MORE EASTWARD AND THUS FORCING THE SOUTHERN UPPER SYSTEM TO OUR 
SOUTH. 
THUS...EXPECT A WARMING TREND WITH INCREASING RAIN CHANCES WEDNESDAY 
INTO THURSDAY...WITH SOME COLDER AIR COMING BACK IN BEHIND THE 
SYSTEM BY FRIDAY.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
IMPROVING CONDITIONS THIS PERIOD.  SOUTHERN EDGE OF CLOUD WILL WORK 
N FROM SOUTHERN WV TO NORTHERN WV BY 12Z SAT.  CIGS WILL BE VFR AT 
4-6KFT UNTIL IT CLEARS...WITH OCCASIONAL MVFR CIGS /2.5KFT OR SO/ IN 
THE MTNS EARLY ON.  THE NORTHERN MTNS INCLUDING EKN CAN STILL HAVE 
MVFR VSBY IN SNOW EARLY ON.  CONDITIONS DURING THE DAY SAT WILL BE 
VFR WITH FEW IF ANY CLOUD.
GUSTY W TO NW SFC FLOW WILL DIMINISH OVERNIGHT AND THEN SWITCH TO SW 
SAT.  STRONG W TO NW FLOW ALOFT OVERNIGHT WILL BECOME MODERATE W TO 
SW DURING THE DAT SAT.
AFTER 00Z SUNDAY...
NO SIGNIFICANT IFR CONDITIONS ARE EXPECTED AT THIS TIME.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...CL/SL/JMV
NEAR TERM...CL
SHORT TERM...SL
LONG TERM...JMV
AVIATION...TRM