FXUS61 KRNK 011058
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
558 AM EST TUE DEC 1 2009

.SYNOPSIS...
HIGH PRESSURE WILL BUILD JUST SOUTH OF THE AREA TODAY BEFORE
SLIDING EAST AND OFFSHORE TONIGHT. STRONG LOW PRESSURE ALONG THE
GULF COAST TONIGHT WILL LIFT NORTH ALONG THE APPALACHIANS
WEDNESDAY INTO WEDNESDAY NIGHT...REACHING NEW ENGLAND EARLY
THURSDAY. THIS SHOULD BRING ANOTHER ROUND OF SIGNIFICANT RAINFALL
FOR MID WEEK. MUCH COLDER AIR WILL FOLLOW THE TRAILING COLD FRONT
INTO THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
STILL SEEING SOME LOW CLOUDS ACROSS THE FAR WEST ATTM OTRW EXPECT 
VERY DRY AIR TO WIN OUT THIS MORNING AS HIGH PRESSURE BUILDS IN FROM 
THE SW AND REMAINS IN PLACE TODAY. MAY ALSO SEE SOME HIGH CLOUDS 
SHEAR NE THRU THE RIDGE LATER TODAY BUT NOT ENOUGH TO DETER MAINLY 
SUNNY SKIES THRU AFTERNOON UNDER SUBSIDENCE AND FAST WESTERLY 
CONFLUENT FLOW ALOFT. ALSO WITH THE 85H COLD POCKET QUICKLY PULLING 
OUT AND THE SURFACE HIGH RIDGING IN SHOULD SEE THE WIND GRADIENT 
WEAKEN THIS MORNING ALLOWING FOR LIGHTER WINDS BY AFTERNOON. QUICK 
REBOUND IN TEMPS ALOFT PLUS HEATING OF DRY AIR UNDER WESTERLY FLOW 
SUGGESTS TEMPS LIKELY PUSHING THE WARM SIDE OF MOS SO NUDGED UP IN 
SPOTS THIS AFTERNOON. 

SURFACE RIDGE QUICKLY KICKS OFFSHORE OVERNIGHT AS LOW PRESSURE 
DEVELOPS ALONG THE GULF COAST AND STARTS TO LIFT NORTH LATE. 
INCREASING SE FLOW BETWEEN THE TWO SHOULD BEGIN TO INCREASE MOISTURE 
PRETTY QUICK ESPCLY AFTER MIDNIGHT AHEAD OF A SLUG OF ISENTROPIC 
LIFT PROGGED JUST SW OF THE CWA BY MORNING. HOWEVER THE COLUMN 
REMAINS RATHER DRY IN THE LOW LEVELS EXCEPT OVER THE FAR SW WHERE 
UPSLOPE LIKELY WILL CAUSE PRECIP TO OVERCOME THIS DRY POCKET SOONER. 
THIS MAY PRODUCE IN SPOTTY -RA BY DAYBREAK AND IF FASTER/HEAVIER 
COULD RESULT IN SOME MIX TO WET SNOW AT ELEVATION PER EVAPORATION SO 
KEEPING A MENTION OTRW 20/30 POPS AT BEST. ELSW EXPECT A QUICK 
INCREASE IN HIGH CLOUDS DURING THE EVENING THEN THICKENING OVERNIGHT 
BUT STILL DRY. LOW TEMPS TRICKY PENDING TIMING OF THICKER CLOUD 
CANOPY AND HOW FAST THINGS COOL OFF IN THE EVENING WHEN THE CIRRUS IS 
RELATIVELY THIN. APPEARS COLDEST NE/VALLEYS AND WARMER AT ELEVATION 
AS THE SE JET INCREASES SO RANGE FROM 40ISH RIDGES TO SOME LOWER 30S 
VALLEYS OK FOR NOW.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
CLOSED UPPER LOW OVER NRN MEXICO IS BEGINNING TO MOVE EASTWARD...AND 
SHOULD ACCELERATE AND TRACK EAST-NORTHEAST IN RESPONSE TO THE 
DIGGING NR STREAM TROUGH ENTERING THE NWRN U.S. THE ASSOCIATED  
DEEPENING SFC LOW WILL TRACK NORTHEASTWARD OUT OF THE GULF OF MEXICO 
WEDNESDAY...AND MODELS CONTINUE TO SHOW A TRACK WEST OF THE 
MTNS...WITH THE LOW IN UPSTATE NY BY THU MORNING. WITH A TRACK WEST 
OF THE MTNS...AND MODELS CONTINUING TO SHOW A VERY STRONG 
SOUTHEASTERLY LLJ WEDNESDAY...WE HAVE OPTED TO ISSUE A HIGH WIND 
WARNING FOR THE SW MTNS OF VA AND INTO MERCER COUNTY WV. THIS AREA 
IS CLIMATOLOGICALLY FAVORED FOR HIGH MOUNTAIN WAVE WIND GUSTS WITH A 
STRONG SOUTHEAST JET. ALL MODELS HAVE A 60+ KNOT JET AT 850 MBS 
DURING THE DAY WED. STRONGEST JET IS AROUND 18Z...BUT STRONG WIND 
GUSTS MAY OCCUR IN THE MORNING SINCE THIS WILL BE BEFORE RAIN STARTS 
AND CEILINGS LOWER. HAVE THE TIME WINDOW FOR THE HIGH WIND WATCH 600 
AM WED THRU MIDNIGHT...WITH GUSTS UP TO 60 MPH. AS FOR THE RAIN 
WED...HAVE KEPT WITH THE SLOWER TIMING CLOSER TO THE NAM WITH THE 
SFC LOW TRACKING SO FAR WEST. WITH NO DAMMING EVIDENT...SHOULD SEE 
RAIN BREAK OUT EARLIEST IN UPSLOPE AREAS OF NW NC AND FAR SW VA. 
SHOULD HAVE RAIN ACROSS THE CWA BY THE END OF THE DAY. FINALLY... 
WITH MODELS STILL INDICATING A CONVECTIVE LINE DEVELOPING ALONG THE 
SFC FRONT ACROSS GA AND SC...THIS MAY TEND TO CUT OFF DEEP MOISTURE 
TRANSPORT INTO THE REGION. HAVE KEPT THE QPF LOWER THAN HPC GUIDANCE 
FOR THIS REASON...EXCEPT FOR HEAVIER UPSLOPE RIGHT ALONG THE BLUE 
RIDGE. THERE IS A SLIGHT CHC THAT THE CONVECTION MAY REACH THE 
PIEDMONT AREAS LATE IN THE DAY AND IN THE EVENING...SO I HAVE 
INCLUDED A SLIGHT CHC OF TSTMS OUT THAT WAY. STILL LOOKS LIKE A DRY 
SLOT WILL MOVE INTO THE AREA OVERNIGHT AS THE UPPER JET SHIFTS EAST 
TO OVER THE SRN APPLNS. STRONGEST COLD AIR ADVECTION SHOULD HOLD OFF 
UNTIL DURING THE DAY THU...SO NOT MUCH THREAT OF SNOW IN THE MTNS 
EVEN LATE WED NIGHT.

WITH MORE OF A WEST...OR EVEN WEST-SOUTHWEST FLOW BEHIND THE FRONT 
LATE WED NIGHT AND THURSDAY...IT IS NOT THE BEST UPSLOPE COMPONENT. 
HOWEVER...MODELS DO SHOW DEEP ENOUGH MOISTURE FOR SOME SHOWERS...SO 
I HAVE KEPT THE WESTERN UPSLOPE POPS GOING. THE RAIN SHOWERS WILL BE 
CHANGING TO SNOW SHOWERS IN THE HIGHER ELEVATIONS THU MORNING...AND 
IF THE SHOWERS CAN KEEP GOING...WILL CHANGE OVER INTO THE LOWER 
ELEVATIONS IN THE LATE AFTERNOON. SOME LIGHT SNOW ACCUMS ARE 
POSSIBLE THURSDAY ABV 3K FEET. WILL BE A COLD DAY THURSDAY IN THE 
MTNS WHERE TEMPS WILL STRUGGLE TO GET OUT OF THE 30S. 

HIGH PRESSURE RIDGES EASTWARD FROM THE TN AND OHIO VALLEYS ACROSS 
THE CENTRAL APPLNS FRIDAY...AND ALTHOUGH THE LOW LEVEL FLOW REMAINS 
WEST TO NORTHWEST WITH SOME LOW LEVEL MOISTURE...IT LOOKS LIKE 
UPSLOPE SHOWERS WILL BE DECREASING WITH MORE OF AN ANTI-CYCLONIC 
FLOW. I HAVE LOWERED THE POPS FRIDAY...AND CONFINED THEM TO JUST THE 
FAR WESTERN SLOPES. FRIDAY WILL BE CHILLY ACROSS THE CWA- BUT 
ESPECIALLY IN THE MTNS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THE 00Z GFS/ECMWF MIX SHOWS A WAVE ROUNDING THE TROUGH IN THE
SOUTHERN PLAINS...GRABBING SOME GULF MOISTURE...THEN PRODUCING
LIGHT SNOW IN THE WEST AND RAIN/SNOW OUT EAST LATE FRIDAY NIGHT
AND SATURDAY. HOWEVER THE DEEPER MOISTURE LOOKS TO REMAIN CLOSER
TO THE COAST WITH INLAND PRECIP MAINLY THE RESULT OF THE MID LEVEL
SUPPORT AND UPPER JET TO THE WEST OF THE OFFSHORE COASTAL LOW. JUST
HOW MUCH THE UPPER TROF CAN SHARPEN...AND HOW CLOSE TO THE COAST
THE SURFACE LOW TRACKS KEYS TO THE AMOUNT OF RETURN INLAND
MOISTURE...AND WHETHER OR NOT THE DEEP RH GETS SHEARED OUT TO THE
NE WITH THE FAST FLOW UNDER THE POSITIVE TILTED TROF. FOR NOW WILL
KEEP THINGS MAINLY DRY AND SEE IF LATER GUIDANCE BRINGS A BETTER
CONSENSUS WITH TIME.

THE COLD FRONTAL BOUNDARY FROM WEDNESDAY NIGHT RAIN
EVENT WILL BE ALONG THE SOUTHERN TIP OF FLORIDA. GIVEN THIS
PATTERN...A MID LEVEL WAVE COULD RIDE OVER THE AREA BUT MOISTURE
SHOULD ONLY CREATE OVERCAST SKIES TO POSSIBLE FLURRIES. THE GFS IS
PRODUCING A TENTH TO A QUARTER INCH OF LIQUID PRECIP...WHICH IS
WAY OVER DONE. LIKING THE ECMWF WITH SHORT WAVES ROUNDING THE
TROUGH...BUT KEEPING BULK OF PRECIPITATION OVER FLORIDA.

TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND WITH THE 
TROUGH REMAINING TO THE WEST FRIDAY NIGHT FOLLOWED BY A CHILLY 
SURFACE HIGH OVER THE WEEKEND. TEMPERATURES ARE EXPECTED TO REBOUND 
EARLY NEXT WEEK WITH A PASSING OF A WARM FRONT.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
CONTINUED VFR CONDITIONS EXPECTED THROUGH MOST OF THE PERIOD WITH
WINDS BACKING SOUTHWEST TODAY...THEN SOUTHEAST AND INCREASING ON
THE RIDGES TONIGHT. LOW PRESSURE ALONG THE GULF COAST WILL SPREAD
MID/HIGH LEVEL MOISTURE IN FROM THE SOUTH LATER TONIGHT WITH CIGS
SLOWLY LOWERING FROM SW TO NE BY WED MORNING. APPEARS ANY MVFR
LEVEL CIGS WILL REMAIN JUST SOUTH OF THE TAF SITES THRU 12Z WED AS
WELL AS MOST PRECIPITATION SO WONT INCLUDE AT THIS POINT.

THIS LOW PRESSURE STORM SYSTEM WILL BRING A GOOD CHANCE FOR
SIGNIFICANT RAIN BY WEDNESDAY...WITH WIDESPREAD IFR
CONDITIONS...POSSIBLY CONTINUING THROUGH THURSDAY. SOUTHEAST WINDS
WILL INCREASE AT KBLF BY DAYBREAK WED WITH GUSTS TO AROUND 20-25
KTS POSSIBLE...AND THEN STRONGER DURING WED INTO WED EVENING.

UPSLOPE SNOW SHOWERS LOOK TO LINGER MVFR CONDITIONS ACROSS SE WVA
INTO FRIDAY WITH VFR ELSEWHERE. ANOTHER STORM SYSTEM COULD BRING
LOWER CIGS AND POSSIBLY A LITTLE MORE WINTRY PRECIP FOR SATURDAY.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...HIGH WIND WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY 
     EVENING FOR VAZ007-009-010-012-015.
NC...NONE.
WV...HIGH WIND WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY 
     EVENING FOR WVZ042.

&&

$$
SYNOPSIS...JH/KM
NEAR TERM...JH
SHORT TERM...JJ
LONG TERM...JH/RCS
AVIATION...AMS/JH/WP