Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 012345
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
745 PM EDT WED OCT 1 2014

.SYNOPSIS...
BACK DOOR FRONT SINKS SOUTH INTO THE CAROLINAS TONIGHT. HIGH
PRESSURE WILL AGAIN WEDGE SOUTH ALONG THE EASTERN SLOPES OF THE
APPALACHIANS THROUGH THURSDAY. A STRONG COLD FRONT ARRIVES LATER
FRIDAY FOLLOWED BY MUCH COOLER AIR FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH THURSDAY/...
AS OF 635 PM EDT WEDNESDAY...

RADAR HAS INDICATED A FEW SHOWERS TRYING TO DEVELOP ALONG THE BLUE
RIDGE EARLY THIS EVENING...ALTHOUGH VERY WEAK INSTABILITY HAS
PREVENTED THEM FROM BECOMING SUSTAINED. RAPID UPDATE MODELS
INDICATE THAT ISOLATED SHOWERS WILL BRIEFLY POP UP FROM TIME TO
TIME DURING THE EVENING...MAINLY NORTH OF HIGHWAY 460 ACROSS THE
PIEDMONT. HAVE THEREFORE ADDED MENTION OF ISOLATED SHOWERS FOR
THIS AREA THROUGH MIDNIGHT.

WILL SEE 500 MB HEIGHT RISES OVERNIGHT AS OUR AREA BECOME
SITUATED UNDER IN A WEAK RIDGE IN BETWEEN DEPARTING UPPER LOW WELL
OFF THE EAST COAST AND THE DIGGING TROF OVER THE CENTRAL UNITES
STATES. WEAK SURFACE COLD FRONT CROSSING INTO NORTH CAROLINA
TONIGHT WILL DISSIPATE BY THURSDAY MORNING. HIGH PRESSURE WILL BE
OVER THE FORECAST AREA ON THURSDAY. THERE MAY BE SOME EASTERLY
FLOW ALONG THE BLUE RIDGE TONIGHT BUT ANY UPSLOPE WILL BE MINIMAL.

MODELS AGAIN BRING LOW CLOUDS BACK IN OVERNIGHT EAST OF THE BLUE
RIDGE. GOOD AGREEMENT IN THE SHORT TERM GUIDANCE THAT CLOUDS WILL
FILL IN BETWEEN 06Z/2AM AND 08Z/4AM. BASED ON THE TRENDS THE PAST
TWO NIGHTS...MAY SPEED THIS UP A COUPLE HOURS. WILL AGAIN HAVE
DENSE FOG IN THE WESTERN RIVER VALLEYS THROUGH EARLY MORNING ON
THURSDAY.

GUIDANCE IN THE PIEDMONT HAS BEEN TOO COLD THE PAST TWO NIGHTS.
WILL TREND A FEW DEGREES WARMER FOR OVERNIGHT LOWS. WILL ALSO
LOWER TEMPERATURES AT HIGHER ELEVATIONS IN THE WESTERN COUNTY
WARNING AREA. PREVAILING SLOW ON THURSDAY IS WESTERLY. LOCATIONS
THAT HAVE ANY CLEARING IN THE MORNING WILL AGAIN HAVE ABOVE NORMAL
HIGH TEMPERATURES.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 257 PM EDT WEDNESDAY...

A COLD FRONT WILL APPROACH THE REGION THURSDAY NIGHT. WITH AN
INCREASE IN MIXING AHEAD OF THIS FRONT...A SHALLOW WEDGE WILL
CONTINUE TO ERODE WITH A PIECE HANGING OVER THE PIEDMONT INTO
FRIDAY MORNING. AS EXPECTED...MODELS HAVE SLOWED DOWN THE TIMING
OF THE FRONT AND PREFRONTAL SHOWERS ENTERING THE AREA. THE FRONT
WILL ENTER THE OHIO VALLEY LATE IN THE MORNING WITH PREFRONTAL
SHOWERS TRACKING ACROSS EXTREME WESTERN PORTION OF THE COUNTY
WARNING AREA (SW VA/SE WV). BY EARLY AFTERNOON...THE FRONT MOVES
OVER THE OHIO VALLEY AND SHOWERS ADVANCE EAST TO THE BLUE RIDGE.
THE FRONT CROSSES OVER THE MOUNTAINS DURING THE EVENING WITH
SHOWERS OVER THE FOOTHILL AND PIEDMONT COUNTIES...EXITING DURING
THE EARLY MORNING HOURS SATURDAY. PRECIPITATION TIMING MAY VARY BY
A COUPLE OF HOURS...AS THE CLOSED LOW CYCLES AND REORGANIZES OVER
THE UPPER MISSISSIPPI FRIDAY.

AS THE FRONT TRACKS TO THE EAST COAST SATURDAY MORNING...THE
CLOSED LOW WILL MOVE EAST INTO THE OHIO VALLEY. A SHORT WAVE WITH
THIS LOW LOOKS TO TRACK FARTHER TO THE SOUTH AND OVER THE
TENNESSEE VALLEY. WITH THIS TRACK...THICK CLOUDS WILL REMAIN OVER
THE MOUNTAINS...ESPECIALLY ALONG WESTERN SLOPES THROUGH SATURDAY
MORNING. AS THIS SHORT WAVE EXITS THE FORECAST AREA...WEST WINDS
WILL INCREASE AND CLOUDS WILL EVENTUALLY DISSIPATE. UNTIL THE
CLOUDS ARE GONE...BREEZY/GUSTS WINDS SHOULD REMAIN ALONG HIGHER
RIDGES THEN MIX DOWN SATURDAY AFTERNOON. HIGH PRESSURE TRACKING
ALONG THE GULF STATES WILL STRETCH NORTH SATURDAY NIGHT ALLOWING
WINDS TO SUBSIDE.

WITH THE SLOWER ARRIVAL OF SHOWERS ON FRIDAY...WARMED
TEMPERATURES A FEW DEGREES WITH L/M 70S WEST AND U70S/L80S EAST.
ALONG WITH WARMER TEMPERATURES...INSTABILITIES WILL
INCREASE...THEREFORE INCREASE THUNDERSTORMS ACTIVITY FROM ISOLATED
TO SCATTERED FRIDAY AFTERNOON/EVENING. A DRAMATIC CHANGE IN
TEMPERATURES AND HUMIDITY WILL BE FELT SATURDAY AS TEMPERATURES
WILL RUN 5F-10F COOLER THAN NORMAL.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 310 PM EDT WEDNESDAY...

FOLLOWING THE PASSING OF A COLD FRONT FRIDAY NIGHT...THE REGION
WILL REMAIN UNDER AN UPPER LEVEL TROUGH THROUGH EARLY NEXT WEEK.
COOLER THAN NORMAL AFTERNOON TEMPERATURES LIKELY THROUGH
MONDAY...THEN MODERATING TOWARDS NORMAL BY MID WEEK. OVERNIGHT
LOWS SATURDAY AND POSSIBLY SUNDAY NIGHT WILL BE COLD WITH
MOUNTAINS TEMPERATURES DROPPING INTO THE 30S...40S IN THE EAST.
FROST IS POSSIBLE ACROSS THE WEST IF WINDS COULD DECOUPLE EARLY
SUNDAY MORNING. GROUND TEMPERATURES WILL REMAIN WARM ENOUGH TO
LIMIT ANY FROST TO ISOLATED AREAS.

THE EASTERN HALF OF THE USA WILL REMAIN UNDER A BROAD BUT FLAT
TROUGH THROUGH TUESDAY. THERE COULD BE A MID LEVEL DISTURBANCE
MOVING ACROSS THE OHIO VALLEY MONDAY...BUT WITH LIMITED
MOISTURE...JUST SEEING AN INCREASE IN CLOUD COVER FOR THE AREA.
TUESDAY MAYBE THE NEXT CHANCE FOR RAIN...AS A FRONT IS SCHEDULED
TO MOVE OVER THE REGION.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 730 PM EDT WEDNESDAY...

IR SATELLITE AND SURFACE OBS SHOW SCT TO BKN CU EAST OF THE BLUE
RIDGE WITH FEW TO CLEAR SKIES ACROSS SE WV. TAF LOCATIONS WILL
REMAIN VFR DURING THE FIRST PART OF THE TAF PERIOD. PATCHY DENSE
FOG IS EXPECTED AGAIN THURSDAY MORNING. IN ADDITION...A WEDGE WILL
SET UP BRINGING IN LOW LEVEL EASTERLY MOISTURE TO LYH/DAN
OVERNIGHT. MVFR/IFR CEILINGS AND VISBYS ARE EXPECTED FROM 08-14Z
ALTHOUGH THEY MAY HANG IN A LITTLE LONGER THAN THAT AT LYH/DAN. BY
THURSDAY AFTERNOON ALL TAF LOCATIONS SHOULD RETURN TO VFR FOR THE
REMAINDER OF THE PERIOD. WIND SPEEDS WILL REMAIN LIGHT GENERALLY
LESS THAN 5 KTS.

EXTENDED AVIATION DISCUSSION...

FRONTAL BOUNDARY AND ASSOCIATED SHOWERS TO IMPACT THE MOUNTAINS BY
LATE FRIDAY MORNING AND THE PIEDMONT IN THE AFTERNOON. SUB VFR
EXPECTED IN HEAVIER SHOWERS OR ISOLATED TSRA.

SHOWERS EXITING THE MTNS BY LATE FRIDAY EVENING AND THE PIEDMONT
TOWARD DAWN SATURDAY. TIMING OF CLEARING IS STILL TRICKY.
SATURDAY SHOULD BE CLEARING OUT IN THE PIEDMONT TO
ROANOKE/BLACKSBURG BUT UPSLOPE MVFR CIGS AT BLF/LWB MAY OCCUR INTO
SAT AFTERNOON...WITH BREEZY NW WINDS.

WINDS DIMINISH SATURDAY NIGHT. THEN VFR SUNDAY.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...RCS
NEAR TERM...AMS/NF
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...AMS/CF



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