FXUS61 KRLX 021041
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
541 AM EST WED DEC 2 2009

.SYNOPSIS...
STRONG LOW PRESSURE SYSTEM PASSES TODAY AND TONIGHT...FOLLOWED BY 
COLDER WEATHER THURSDAY AND FRIDAY. A WEEKEND SYSTEM MAY BRUSH THE 
AREA WITH LIGHT SNOW...THEN HIGH PRESSURE IS BACK SUNDAY AND MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
ATMOSPHERE WILL REQUIRE SOME PRIMING BEFORE RAIN CAN REACH THE 
SURFACE WITH EXTENSIVE STORM SYSTEM LIFTING NORTHEASTWARD FROM THE 
DEEP SOUTH. VARIOUS UPPER LEVEL VORTICITY MAXIMA WILL ADVECT IN OVER 
THE NEXT FEW HOURS AND BEGIN THE CHARGE OF RAINFALL. STRONG SURFACE 
LOW PRECEDES THE UPPER LEVEL TROUGH...AND WILL TAKE A TRACK THROUGH 
CENTRAL KENTUCKY AND OHIO. STRONG PRESSURE GRADIENT BRINGS A STOUT 
SOUTHEAST WIND...ESPECIALLY ACROSS THE MOUNTAINS TO THE EAST...WITH 
SOUTHEASTERLY GUSTS TO 40KTS AT TIMES. ACROSS THE LOWLANDS...THESE 
VELOCITIES WILL BE DAMPENED SOME...BUT STILL SOME OF THE STRONGER 
WINDS SEEN IN A WHILE. 

AS THE SURFACE LOW TRACKS NORTHEAST AND THE SOUTHEASTERLY FLOW SETS 
UP...WILL SEE SOME DOWNSLOPING ON THE WESTERN SLOPES. THIS LOW LEVEL 
DRYING WILL SLIGHTLY DIMINISH THE CHANCES FOR RAIN IMMEDIATELY TO 
THE WEST...AND HAVE DROPPED POPS FROM CATEGORICAL TO CHANCE/LIKELY 
IN THIS AREA DURING THIS SCENARIO. 

WITH THE LOW MOVING OUT...UPPER LEVEL TROUGH AXIS SWINGS THROUGH 
AFTER 03Z...GIVING ONE LAST MAIN BURST OF SHOWERS...BEFORE THE WINDS 
TURN NORTHWESTERLY. 

THIS WILL NOT BE A GREAT WARM AIR ADVECTION PATTERN...AND WILL NOT 
SEE TEMPERATURES ALL THAT MUCH DIFFERENT FROM THE PREVIOUS 
DAY...ALBEIT A COUPLE DEGREES WARMER...AND WILL BE HELD IN CHECK BY 
THE EVAPORATIVE EFFECTS OF RAINFALL. NUDGED MOS NUMBERS UP EVER SO 
SLIGHTLY IN PREFERENCE OF BIAS CORRECTED VALUES TODAY.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
WITH THE LOW PRESSURE SYSTEM TO OUR EAST...LOW LEVEL FLOW BECOMES 
WEST NORTHWEST THAT COMBINED WITH LINGERING MOISTURE...WILL PRODUCE 
SOME UPSLOPE SNOW THURSDAY...CONTINUING THU NIGHT...AND THEN 
GRADUALLY TAPERS OFF ON FRIDAY. THE ABSENCE OF CRYSTAL GROWTH ZONE 
IN CLOUD WILL LIMIT SNOW ACCUMULATIONS.

MINOR CHANGES WERE NOTED TO TEMPERATURES THROUGH THE PERIOD. HIGHS 
ON THURSDAY WILL BE COLDER THAN NORMAL AS H8 COLD ADVECTION 
CONTINUES WITH AROUND -5C TEMPS OR LOWER REMAINING IN PLACE THRU THE 
WEEKEND. GENERALLY WENT CLOSER TO THE COOLER MET.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
GFS WAS TEASING US WITH ITS 06Z RUN THIS MORNING...BRINGING A 
SOUTHERN STREAM SHORTWAVE OVER REGION WITH PLENTY OF GULF MOISTURE 
ON FRIDAY NIGHT AND SATURDAY...A SETUP THAT COULD HAVE BROUGHT 
SEVERAL INCHES OF SYNOPTIC SNOW TO MUCH OF THE REGION.  
HOWEVER...THE 12Z RUNS OF THE GFS/ECMWF/GEM DIG THE SHORTWAVE 
FURTHER SOUTH INTO THE TENNESSEE VALLEY BEFORE TURNING IT NORTHEAST. 
AT BEST...IT LOOKS LIKE WE MAY BE GRAZED BY THE NORTHWESTERN FRINGE 
OF SYNOPTIC SNOW SHIELD...AND WOULD NOT BE SURPRISED IF TRENDS 
CONTINUE AND SYSTEM MISSES US ALTOGETHER.  HAVE CHANCE POPS EAST OF 
THE OHIO RIVER ONLY FOR THIS SYSTEM FOR NOW...AND DO NOT THINK 
SYSTEM IS WORTHY OF AN HWO MENTION.

HAVE A SHORT PERIOD OF UPSLOPE ACTIVITY IN THE NORTHERN MOUNTAINS 
SATURDAY NIGHT BEHIND SYSTEM...WHILE THE LOWLANDS DRY OUT.  PATTERN 
THEN TRANSITIONS TO A ZONAL PATTERN ALOFT WITH HIGH PRESSURE IN 
PLACE AT THE SURFACE FOR SUNDAY AND MONDAY.  THE RESULT WILL BE DRY 
WEATHER...OCCASIONAL BOUTS OF MID/HI CLOUDS IN FAST FLOW ALOFT...AND 
TEMPERATURES MODERATING BACK TO SEASONAL LEVELS.  USED HPC NUMBERS 
FOR TEMPERATURES WITH SOME TWEAKING.  A WEAK DISTURBANCE IN THE FLOW 
MAY PRODUCE PRECIPITATION FOR TUESDAY...SO HAVE SLIGHT CHANCE POPS 
IN THE GRIDS FOR THAT.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
RAIN WILL MOVE INTO THE SOUTH OVER THE NEXT FEW HOURS AND...BRING A 
GENERALLY MVFR DAY. STRONG WINDS WILL BE A CONCERN...ESPECIALLY 
ACROSS THE HIGHER ELEVATIONS...WITH GUSTS TO 40KTS POSSIBLE. BKW AND 
EKN WILL BE MOST AFFECTED. ACROSS THE LOWLANDS...GUSTS TO 30KTS WILL 
BE POSSIBLE. LOW LEVEL WIND SHEAR ALSO POSSIBLE AT BKW.

LOW LEVEL CLOUDS /MVFR/ WILL LINGER THROUGH THE TAF PERIOD.

AFTER 12Z THURSDAY...
IFR CONDITIONS POSSIBLE IN RAIN AND SNOW SHOWERS THURSDAY AND 
THURSDAY NIGHT IN THE NORTHEAST MOUNTAINS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WIND ADVISORY FROM 10 AM THIS MORNING TO 10 PM EST THIS 
     EVENING FOR WVZ033>038-046-047.
OH...NONE.
KY...NONE.
VA...WIND ADVISORY FROM 10 AM THIS MORNING TO 10 PM EST THIS 
     EVENING FOR VAZ003-004.

&&

$$
SYNOPSIS...26/ARJ
NEAR TERM...26
SHORT TERM...ARJ
LONG TERM...CL
AVIATION...26