Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 220146 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 946 PM EDT TUE OCT 21 2014 .SYNOPSIS... LOW PRESSURE CENTERED OVER PENNSYLVANIA WILL DRIFT SOUTHEAST AND OFF THE DELMARVA COAST BY WEDNESDAY. THIS CYCLONE WILL STRENGTHEN INTO A NOR-EASTER THAT WILL PELT NEW ENGLAND WITH HEAVY RAINFALL. BACKLASH FROM THIS SYSTEM WILL BE FELT ACROSS OUR REGION THROUGH THURSDAY IN THE FORM OF CONSIDERABLY CLOUDY COOL WEATHER ALONG WITH GUSTY NORTHWEST WINDS. A MODERATING TREND WILL OCCUR OVER THE WEEKEND AS THE STORM SYSTEM MOVES AWAY FROM THE AREA...REPLACED BY HIGH PRESSURE THAT WILL BRING WARMING CONDITIONS FOR THE WEEKEND...AND ABOVE NORMAL TEMPERATURES FOR THE LAST WEEK OF OCTOBER. && .NEAR TERM /THROUGH WEDNESDAY/...
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AS OF 945 PM EDT TUESDAY... ADJUSTED TEMPS DOWNWARD ACROSS THE MOUNTAINS IN THE NEAR TERM AS THEY ARE COOLING OFF MUCH QUICKER THAN ANTICIPATED. LIGHT RAIN CONTINUES ACROSS SE WV...AND MORE SCATTERED ACROSS THE NRV AND ALLEGHANY HIGHLANDS. AS ANTICIPATED PRECIP AMOUNTS HAVE BEEN LIGHT...WITH JUST A FEW HUNDREDTHS ACROSS SE WV. ALL OTHER PREVIOUS FORECAST DETAILS REMAIN INTACT. AS OF 300 PM EDT TUESDAY... LOW PRESSURE WAS CENTERED OVER PENNSYLVANIA WITH A COLD FRONT TRAILING SOUTHWEST THROUGH THE CENTRAL APPALACHIANS. THE FRONT WILL CROSS THE FORECAST AREA THIS EVENING PRODUCING A FEW SHOWERS...BUT THE GREATER IMPACT WILL BE FOR AREAS NORTHEAST OF OUR REGION WHERE SHOWERS/STORMS WILL INCREASE IN COVERAGE PER THE DEVELOPING/STRENGTHENING AREA OF LOW PRESSURE OVER PENNSYLVANIA. AS THE LOW PASSES OFF THE COAST TONIGHT...THE CYCLONE IS PROGGED TO DEEPEN RAPIDLY...YIELDING TO SURFACE PRESSURE FALLS OF ABOUT 10MB IN 12 HOURS ONCE IT PASSES OFF THE DELMARVA COAST. THIS RAPID STRENGTHENING WILL RESULT IN A NOR-EASTER THAT WILL PELT NEW ENGLAND WITH HEAVY RAIN AND WIND. FOR OUR REGION...WE WILL BE ON THE SOUTHWEST SIDE OF THE STORM...THE DRY SIDE...SO THE BIGGEST BY-PRODUCT WILL BE CLOUD COVER AND WIND. SOME THREAT FOR SHOWERS WILL EXIST OVER THE VA/WV HIGHLANDS...AND ACROSS OUR NORTHEASTERN COUNTIES VCNTY OF BUCKINGHAM WHERE WRAP AROUND MOISTURE FROM THE STORM MAY RESULT IN A PERIOD OF PRECIP TONIGHT AND WEDNESDAY. ASIDE FROM THIS THREAT...THE GREATER INFLUENCE THAT MOST FOLKS WITHIN OUR CWA SHOULD NOTICE WILL BE THE WIND. 85H WINDS ARE PROGGED AROUND 40 KTS FROM THE NORTHWEST WEDNESDAY. THIS WILL TRANSLATE INTO BREEZY CONDITIONS AT THE SURFACE WITH WIND GUSTS OF 20 TO 30 MPH...AND 30 TO 35 MPH IN THE HIGHER ELEVATIONS. TEMPERATURES TONIGHT WILL BE COOL...BUT SHOULD REMAIN ABOVE FREEZING DUE TO THE CLOUD COVER AND MIXING FROM THE WIND. TEMPERATURES WEDNESDAY WILL STRUGGLE TO REACH 50 IN THE MOUNTAINS...AND 60 IN THE PIEDMONT... CLOUD COVER AND LOWERING THICKNESSES FROM THE DEVELOPING CYCLONE PUTTING A DAMPER ON ANY CONTRIBUTION FROM SOLAR INSOLATION.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... AS OF 300 PM EDT TUESDAY... WE WILL BE WATCHING AN OCCLUDED LOW/NOR-EASTER DRIFT OFF THE MID ATLANTIC COAST WEDNESDAY NIGHT AND THURSDAY. SHORT WAVES PIVOTING AROUND THIS LOW WILL PERIODICALLY TRACK OVER THE FORECAST AREA. MOISTURE WILL BE LIMITED BUT COULD SEE A PASSING SHOWER OR TWO ACROSS THE GREENBRIER VALLEY AND ALLEGHANY HIGHLANDS THROUGH THE DAY THURSDAY. MOST NOTABLE WILL BE A PRESSURE GRADIENT OVER THE REGION BETWEEN THE NOR-EASTER AND APPROACHING HIGH PRESSURE FROM THE WEST. BREEZY/GUSTY CONDITIONS LIKELY ALONG RIDGE TOPS AND POSSIBLY FOR LOWER ELEVATIONS IF SKIES BECOME MOSTLY CLEAR. MOST CLEAR SKIES POSSIBLE FOR THE SOUTHWEST CORNER OF RNK CWA (BLUEFIELD TO GRAYSON COUNTY). DOWNSLOPE FLOW SHOULD ALSO KEEP THE EAST MOSTLY CLEAR ESPECIALLY ACROSS SOUTHSIDE...BUT THE WINDS WILL NOT BE AS STRONG EAST AS IT WILL BE OVER THE MOUNTAINS. CLOUDS BEGIN TO CLEAR ACROSS THE ENTIRE CWA THURSDAY NIGHT...WHILE THE PRESSURE GRADIENT RELAXES. ANY WINDS OVERNIGHT THURSDAY WILL REMAIN ALOFT AND ABOVE THE INVERSION. MODELS ARE BRINGING ANOTHER UPPER LEVEL TROUGH ACROSS THE OHIO VALLEY AND OVER THE MID ATLANTIC FRIDAY. THIS TROUGH WILL HAVE LESS MOISTURE TO WORK WITH THAN THE NOR-EASTER...THEREFORE RAINFALL CHANCES ARE EVEN LOWER BUT NOT ZERO ALONG WESTERN SLOPES FRIDAY AFTERNOON. THIS TROUGH QUICKLY MOVES EAST FRIDAY NIGHT WITH HEIGHTS BUILDING THERE AFTER. COOL NORTHWEST FLOW ON THE BACK SIDE OF THE MID ATLANTIC LOW/NOR- EASTER WILL KEEP AFTERNOON TEMPERATURES COOLER THAN NORMAL THURSDAY AND FRIDAY. OVERNIGHT LOWS MAY DIP INTO THE 30S ACROSS THE MOUNTAINS EACH NIGHT WHILE MIXING WILL DETER FROST FROM FORMING. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 PM EDT TUESDAY... A LARGE AREA OF HIGH PRESSURE WILL COVER MOST OF THE CONUS...FROM THE ROCKIES MOUNTAINS TO THE EAST COAST...STARTING SATURDAY. THE UPPER RIDGE AXIS WILL BE ALIGNED OVER THE EAST COAST ON MONDAY. BASICALLY...HEIGHTS WILL INCREASE EACH DAY WHICH TRANSLATES INTO WARMER THAN NORMAL TEMPERATURES FOR THE AREA THROUGH MONDAY. HEIGHTS BEGIN TO LOWER ON TUESDAY AS A COLD FRONT ENTERS THE MISSISSIPPI VALLEY. SURFACE HIGH PRESSURE WILL ACCOMPANY RIDGING ALOFT THIS WEEKEND. THIS SURFACE HIGH WILL ENCOMPASS THE EASTERN HALF OF THE US...ESSENTIALLY BLOCKING ANY RETURN FLOW FROM THE GULF. WITH NO LIFT AND/OR MOISTURE...HIGH CONFIDENCE TO RUN WITH ZERO POPS INTO MONDAY NIGHT. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... AS OF 730 PM EDT TUESDAY... CLOSED LOW OVER PENNSYLVANIA WILL DRIFT OFF THE DELMARVA COAST TONIGHT AND WEDNESDAY...AND WILL BE THE PRIMARY FOCUS FOR WEATHER THROUGHOUT THE REGION THE NEXT SEVERAL DAYS. THIS FEATURE WILL RESULT IN THE DEVELOPMENT OF A NOR-EASTER THAT WILL PELT THE NEW ENGLAND COAST WITH HEAVY RAIN A WIND...AND WILL MOST LIKELY IMPACT AIR TRAFFIC FOR MANY OF THE NEW ENGLAND TERMINALS FOR THE REMAINDER OF THIS WORK WEEK. FOR OUR LOCAL REGION...BKN-OVC CLOUD BASES WILL BE COMMON THROUGH WEDNESDAY...MAINLY VFR EAST OF THE BLUE RIDGE...AND MVFR ACROSS THE MOUNTAINS. SCATTERED SHOWERS ARE POSSIBLE OVER THE VA/NC HIGHLANDS...AND ACROSS VIRGINIA NORTH OF A KROA/KLYH LINE...HIGHWAY 460. LITTLE OR NO SHOWER THREAT IS EXPECTED FROM THE VA/NC STATE LINE AND POINTS SOUTH. WITH THE DEVELOPING CYCLONE TO OUR NORTHEAST...BACKLASH WILL BE FELT THROUGHOUT OUR REGION IN THE FORM OF GUSTY NORTHWEST WINDS. 3000-5000FT AGL WINDS OF 40 KTS ARE PROGGED FOR WEDNESDAY. THIS WILL RESULT IN GUSTY SURFACE WINDS AT ALL TERMINALS. 20-30KT SURFACE GUSTS WILL BE COMMON. EXTENDED AVIATION DISCUSSION... THE UPPER LEVEL LOW WILL SLOWLY MEANDER ABOUT THE MID-ATLANTIC REGION THROUGH THURSDAY...THEN BEGIN TO SHIFT TOWARD THE NORTHEAST AND AWAY FROM THE AREA BY FRIDAY. IMPACTS...ESP FROM WIND...WILL CONTINUE IN ADDITION TO WIDELY SCATTERED -SHRA ACROSS THE VA/WV HIGHLANDS WEDNESDAY NIGHT AND EARLY THURSDAY. MVFR CLOUDS WILL THUS BE COMMON ACROSS THE MOUNTAINS DURING THIS TIME PERIOD...BUT FROM ROA TO LYH TO DAN CONDITIONS ARE LIKELY TO REMAIN VFR THROUGH THIS PERIOD. VFR CONDITIONS ARE ANTICIPATED FRIDAY-SUNDAY. WINDS MAY CONTINUE TO BE A CONCERN FRIDAY AND SATURDAY...BUT ARE EXPECTED TO DIMINISH FOR SUNDAY INTO MONDAY AS HIGH PRESSURE BUILDS OVER THE REGION FROM THE WEST. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...CF/PM SHORT TERM...RCS LONG TERM...RCS AVIATION...DS/PM

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