Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 250604 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 204 AM EDT FRI APR 25 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT. MEANWHILE...A COLD FRONT WILL HEAD EASTWARD...AND SHOULD CROSS OVER THE MID ATLANTIC BY FRIDAY TO BRING SCATTERED SHOWERS. HIGH PRESSURE WILL RETURN TO PROVIDE A DRY AND MILD WEEKEND...BEFORE AN UPPER LEVEL AREA OF LOW PRESSURE PROVIDES COOLER AND WETTER CONDITIONS NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 950 PM EDT THURSDAY... MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND DEW POINTS FOR TONIGHT. THIS EVENING RNK 00Z/8PM SOUNDINGS SHOWED MOISTURE INCREASING AROUND 718MB WITH A PWAT AROUND 0.5 INCHES. THE 18Z NAM GFS AND HRRR HINT AT MOISTURE SLIDING NORTH ACROSS THE SOUTHERN BLUE RIDGE MOUNTAINS LATE TONIGHT. AS HIGH PRESSURE SLIDES EAST INTO THE ATLANTIC OCEAN TONIGHT INTO FRIDAY MORNING...MOISTURE WILL STREAM NORTHWARD INTO OUR REGION. HIGH AND MID CLOUDS WILL HINDER RADIATIONAL COOLING OVERNIGHT. LOW TEMPERATURES OVERNIGHT WILL GENERALLY BE IN THE MID 40S TO THE LOWER 50S WITH CLOUDS AND WEAK WARM AIR ADVECTION ALOFT. A COLD FRONT TO OUR WEST AND ITS ASSOCIATED WARM FRONT WILL TRAVEL EAST TONIGHT INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT. AT THIS POINT...MADE NO CHANGES WITH FRIDAY CONVECTION. HAVE A GOOD NIGHT. AS OF 635 PM EDT THURSDAY... RAISED EARLY EVENING TEMPERATURES UP A FEW DEGREES WITH SOLAR HEATING. HIGH PRESSURE WILL SLIDE EAST INTO THE ATLANTIC THIS EVENING INTO TONIGHT. A COLD FRONT AND ITS ASSOCIATED WARM FRONT WILL TRAVEL EAST TONIGHT INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT. LOW TEMPERATURES OVERNIGHT WILL GENERALLY BE IN THE MID 40S TO THE LOWER 50S WITH CLOUDS AND WEAK WARM AIR ADVECTION ALOFT. LATEST RNK WRFARW AND HRRR SUPPORT CURRENT ARRIVAL TIME FOR CONVECTION ALONG AND AHEAD OF COLD FRONT. NO MAJOR CHANGES IN CLOUDS...PRECIPITATION AND POPS TONIGHT INTO FRIDAY. WILL MAKE ADDITIONAL CHANGES IN ISC GRIDS LATER THIS EVENING. AS OF 355 PM EDT THURSDAY... SKIES HAVE CLEARED DURING THE PAST FEW HOURS TO ALLOW TEMPERATURES TO REACH THE LOWER 60S TO THE LOWER 70S THIS AFTERNOON. HIGH PRESSURE SHOULD DRIFT OFFSHORE LATER TONIGHT. MEANWHILE...A COLD FRONT WILL CROSS OVER THE OHIO RIVER VALLEY. THE 12Z NAM/ECMWF/GFS MODEL GUIDANCES HAVE SLOWED DOWN THE ARRIVAL OF THIS FRONT BY A FEW HOURS...SO POPS WERE TAPERED DOWNWARD DURING THURSDAY NIGHT FROM THE PREVIOUS FORECAST. LOW TEMPERATURES WERE HELD IN THE MID 40S TO THE LOWER 50S DUE TO CLOUD COVER AND WEAK WARM AIR ADVECTION ALOFT. POPS WERE INCREASED LATER ON FRIDAY MORNING HOURS DUE TO GOOD AGREEMENT AND A LITTLE MORE OVERALL COVERAGE PORTRAYED IN THE MODELS. SHOWERS SHOULD LINGER INTO THE AFTERNOON...BEFORE THE FRONT HEADS TOWARD THE COAST BY SUNSET. QPF AMOUNTS WERE ALSO INCREASED SLIGHTLY TO AROUND A QUARTER OF AN INCH. HOWEVER...WINDS SHOULD TURN TO THE WEST AND BECOME GUSTY AFTER THE FRONTAL PASSAGE...AND END ANY OF THE REMAINING RAINFALL. CHANCES OF THUNDER WERE ONLY PLACED IN SOUTHSIDE VIRGINIA WERE BUFKIT MODEL SOUNDINGS SHOW CAPE EXCEEDING 500 J/KG DURING THE AFTERNOON. SPC KEEPS ANY SEVERE WEATHER THREAT WELL TO THE EAST OF OUR CWA. HIGHS ON FRIDAY WERE KEPT ON THE SLIGHTLY COOLER SIDE OF GUIDANCE DUE TO CLOUDS AND RAIN...WITH LOWER 60S TO LOWER 70S EXPECTED. && .SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... AS OF 315 PM EDT THURSDAY... MOST PRECIP WILL HAVE EXITED THE REGION AT THE BEGINNING OF THIS PERIOD...SAVE SOUTHSIDE VA/NC PIEDMONT AND THE GREENBRIER VALLEY. GOOD BURST OF WIND BEHIND THIS COMPACT YET DECENT SHRTWV...WITH SOME 30 KT GUSTS FRIDAY EVENING AT THE USUAL LOCATIONS. SLIGHTLY COOLER AIR SLIPS INTO THE GREENBRIER VALLEY AND SOUTHERN SHENANDOAH BEHIND THIS BOUNDARY...BUT WAA RETURNS QUICKLY ACROSS THE SOUTHERN HALF OF THE CWA. ANOTHER DISTURBANCE DROPPING THROUGH THE GREAT LAKES LATE SATURDAY...MAY ALLOW SCATTERED SHOWERS AND A THUNDERSTORMS TO FORM JUST AHEAD OF A COLD FRONT WHICH STALLS AROUND ELKINS WV...WITH SOME OF THESE WEAKENING...PERHAPS AS THEY MOVE INTO THE GREENBRIER VALLEY AND THE SOUTHERN SHENANDOAH. SOMETIMES MODELS STRUGGLE WITH THIS REGIME...SO FOR NOW AT LEAST WENT WITH SLT CHC POPS IN THESE AREAS. H85 TEMPS IN THE LOWER TEENS TO NEAR +15C CONTINUE FOR SUNDAY...WITH SOME SPOTS TOUCHING 80F POSSIBLY SATURDAY AND SUNDAY. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 330 PM EDT THURSDAY... THE NEXT WORKWEEK IS SHAPING UP TO BE ON THE WET SIDE AS A MASSIVE UPPER LEVEL LOW PINWHEELS EAST FROM THE CENTRAL AND NORTHERN PLAINS. WILL START MONDAY OUT WITH COOL HIGH PRESSURE WEDGING SOUTHWARD AGAINST THE EASTERN FACE OF THE APPALACHIANS...MAINTAINING A COOL EASTERLY WIND ACROSS OUR AREA. A WARM FRONT WILL NORTH ALONG THE MISSISSIPPI RIVER VALLEY...BUT WILL GET HUNG UP AGAINST THE APPALACHIANS. AS SUCH...EXPECT SHOWERY WEATHER MONDAY AND TUESDAY... WITH AN OUTSIDE CHANCE FOR THUNDERSTORMS ACROSS THE MOUNTAIN EMPIRE AND PERHAPS THE NORTH CAROLINA FOOTHILLS...WHERE THE STABILIZING AFFECT OF THE HIGH PRESSURE WEDGE WILL BE WEAKEST. WILL SEE A BETTER THREAT FOR THUNDERSTORMS ON WEDNESDAY AS THE LOW PRESSURE SYSTEM NEARS THE REGION...ALLOWING THE WARM FRONT TO LIFT NORTHWARD BEFORE THE TRAILING COLD FRONT MOVES IN. EASTERLY FLOW AROUND THE HIGH WILL ALSO RESULT IN COOLER TEMPERATURES...AND THEREFORE UNDERCUT MODEL GUIDANCE BY A FEW DEGREES. HOWEVER...TEMPERATURES REMAIN LOW CONFIDENCE...AND BELIEVE IT IS POSSIBLE THAT DID NOT GO LOW ENOUGH FOR AFTERNOON HIGHS MONDAY AND PARTICULARLY TUESDAY. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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AS OF 200 AM EDT FRIDAY... CLOUDS WILL INCREASE IN COVERAGE AHEAD OF THE APPROACHING COLD FRONT. THIS FRONT IS PROGGED TO TRACK OVER THE MID ATLANTIC DURING THE DAY FRIDAY. VFR CLOUD BASES THIS MORNING WILL LOWER TO MVFR CEILINGS BETWEEN DAYBREAK AND 11AM...WITH SCATTERED TO NUMEROUS SHOWERS AND EMBEDDED SCATTERED THUNDERSTORMS CROSSING THE AREA BETWEEN 14Z/10AM AND 21Z/4PM. FRONT IS EXPECTED TO CLEAR THE AREA BY 21Z/4PM WITH RETURN OF VFR CONDITIONS THIS EVENING...TONIGHT... AND SATURDAY. BEHIND THE FRONT...FOR ABOUT A 24 HOUR PERIOD...WINDS WILL BE GUSTY OUT OF THE NORTHWEST...DIMINISHING BY SUNSET SATURDAY. EXTENDED AVIATION DISCUSSION... VFR CONDITIONS SHOULD PREVAIL BOTH SATURDAY AND SUNDAY. CLOUD COVER WILL STEADILY INCREASE BY MONDAY...AS A LOW PRESSURE SYSTEM SLOWLY ARRIVES FROM THE WEST. CONDITIONS MAY DROP BELOW VFR WHEN SCATTERED SHOWERS MOVE OVER THE MID ATLANTIC DURING LATE MONDAY...AND CHANCES FOR MVFR ARE EVEN BETTER ON TUESDAY DUE TO PROLONGED CLOUDS AND RAIN.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PW NEAR TERM...KK/PW SHORT TERM...KM LONG TERM...NF AVIATION...PM

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