Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 211627 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1227 PM EDT MON APR 21 2014 .SYNOPSIS... SURFACE HIGH PRESSURE WILL LINGER OVER THE AREA THROUGH THIS AFTERNOON...KEEPING WARM AND DRY WEATHER IN PLACE. A COLD FRONT OVER THE UPPER MIDWEST WILL SWEEP SOUTHEAST THROUGH THE AREA ON TUESDAY...PRECEDED AND ACCOMPANIED BY SCATTERED SHOWERS AND THUNDERSTORMS. HIGH PRESSURE IS EXPECTED TO RETURN TO THE AREA ON WEDNESDAY...BRINGING BLUSTERY AND COOLER WEATHER. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM EDT MONDAY... BASICALLY A TEMP FORECAST THROUGH THE AFTERNOON GIVEN VERY DRY AIR IN PLACE PER MORNING RAOBS AND UNDER THE LINGERING RIDGE. MAY SEE SOME HIGH/MID CLOUDS WORK INTO THE WEST LATER ON...OTRW STAYING SUNNY/WARMER THAN SUNDAY PER WARMING ALOFT AND STRONG HEATING. ALTHOUGH ACTUAL THICKNESS NUMBERS GIVING HIGHS A CAT OR SO BELOW MOS...LATEST LOCAL SCHEME VALUES SUPPORT CLOSER TO THE WARMER MAV FORECAST HIGHS. THIS DESPITE ONLY LIGHT MIXING WHICH MAY ACTUALLY KEEP THE SE COOLER WHERE MORE OF A LIGHT NE TRAJECTORY WILL PERSIST. THUS ADJUSTED HIGHS UP CENTRAL AND WEST WHERE MORE ON THE ORDER OF MID 70S LIKELY WITH PERHAPS A FEW LATE DAY UPPER 70S POSSIBLE. PREVIOUS DISCUSSION AS OF 300 AM EDT MONDAY... SURFACE RIDGE OF HIGH PRESSURE WILL LINGER OVER THE BLACKSBURG FORECAST AREA TODAY...BRINGING MOSTLY SUNNY AND WARM TEMPERATURES. 850 MILLIBAR TEMPERATURES ARE FORECAST TO RISE 8C ACROSS THE PIEDMONT...AND 3-4C ACROSS THE MOUNTAINS WITH RESPECT TO YESTERDAY...AND DESPITE SOME HIGH LEVEL CLOUDS...SHOULD BE SUFFICIENT TO SUPPORT DAYTIME HIGHS IN THE 70S IN MOST LOCATIONS...EXCLUDING HIGHER ELEVATIONS WHERE TEMPERATURES WILL BE HARD PRESSED TO CLIMB OUT OF THE 60S. NEXT UPSTREAM SHORT WAVE TROF AND ASSOCIATED INCREASE IN MID LEVEL CANOPY WILL BEGIN TO IMPACT THE REGION TONIGHT. DESPITE RELATIVELY LOW DEW POINTS AND NEARLY CALM WINDS...INCREASING CLOUDS SHOULD CUT BACK ON EXTENT OF RADIATIVE COOLING SUCH THAT MOST AREAS FALL BACK ONLY INTO THE 40S. LEADING EDGE OF SCATTERED SHOWERS IN ADVANCE OF NEXT COLD FRONT MAY ENCROACH THE WESTERN PORTION OF THE BLACKSBURG FORECAST AREA TOWARD DAYBREAK ON TUESDAY...BUT MAIN IMPACT OF THIS NEXT SYSTEM WILL OCCUR AFTER DAYBREAK. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 300 AM EDT MONDAY... THE MAIN FEATURE DURING THIS PORTION OF THE FORECAST IS A COLD FRONT THAT WILL CROSS THE REGION ON TUESDAY. LATEST MODEL GUIDANCE OFFERS SOLUTIONS THAT HIGHLIGHT THE BEST COVERAGE DURING THE MORNING ACROSS THE WESTERN HALF OF THE AREA. BY THE AFTERNOON...THE BEST COVERAGE JUMPS TO ALONG THE SOUTHERN AND SOUTHEASTERN PARTS OF THE REGION WITH A QUICKER PROGRESSION OF DRYING IN THE WEST AS COMPARED TO GUIDANCE OF 12 HOURS AGO. THE LATEST ADJUSTMENTS HAVE BEEN INCORPORATED INTO THE FORECAST PACKAGE FOR THIS MORNING. WE WILL CONTINUE TO MENTION THE POTENTIAL FOR A SLIGHT CHANCE OF THUNDERSTORMS COINCIDENT TO AND JUST IN ADVANCE OF THE FRONT FROM MIDDAY THROUGH THE AFTERNOON. COOLER AND DRIER HIGH PRESSURE WILL WORK ITS WAY INTO THE AREA IN THE WAKE OF THE FRONT AND BE SETTLED OVER THE REGION BY WEDNESDAY NIGHT. INITIALLY...THE PRESSURE GRADIENT BETWEEN THE TWO SYSTEM WILL HELP PROMPT GUSTY WINDS TUESDAY NIGHT THROUGH WEDNESDAY. AT THIS POINT THE STRONGEST GUSTS LOOK TO BE AT THE HIGHEST ELEVATIONS IN THE 25 TO 30 MPH RANGE. EAST OF THE BLUE RIDGE...GUSTS WILL BE MORE ON THE ORDER OF 15 TO 20 MPH. LATE WEDNESDAY NIGHT INTO THURSDAY...THE COLDEST AIR WILL BE ACROSS THE REGION WITH MID TO UPPER 30S FOR LOWS ACROSS THE MOUNTAINS AND UPPER 30S TO LOWER 40S ACROSS THE PIEDMONT. THERE MAY BE SOME PATCHY FROST ACROSS PARTS OF SOUTHEAST WEST VIRGINIA AND NEIGHBORING PARTS OF SOUTHWEST VIRGINIA. HOWEVER...THE GROWING SEASON STILL HAS NOT STARTED IN THIS PARTS...SO NO FROST ADVISORIES ARE ANTICIPATED. THE NEXT COLD FRONT TO IMPACT OUR REGION IS NOT EXPECTED TO ARRIVE UNTIL FRIDAY. HOWEVER...MOISTURE IN ADVANCE OF THE FRONT WILL YIELD TO INCREASING CLOUD COVER THURSDAY NIGHT...WITH THE POTENTIAL FOR SOME ISOLATED TO SCATTERED SHOWERS ACROSS THE MOUNTAINS BY DAYBREAK FRIDAY. && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 1245 PM EDT SUNDAY... MODERATING TEMPERATURES ARE EXPECTED ON FRIDAY AS LOW LEVEL WINDS STRENGTHEN FROM THE SOUTHWEST AND WARM AIR ADVECTION PREDOMINATES. A COLD FRONT WILL APPROACH THE AREA FRIDAY MORNING AND BE EAST OF THE AREA BY FRIDAY EVENING. SCATTERED SHOWERS AND SOME ISOLATED THUNDERSTORMS WILL ACCOMPANY THE FRONT. BEHIND THE FRONT...MODEL GUIDANCE DEVIATES ENOUGH TO PROVIDE UNIQUELY DIFFERENT WEATHER PATTERN SOLUTIONS FOR OUR REGION OF THE COUNTRY. THE GFS SOLUTION DEEPENS THE PARENT LOW OF THE COLD FRONT AND BRINGS IT SOUTH TO CAPE COD BY SUNDAY MORNING. THIS KEEPS A PREVAILING NORTHWEST FLOW WHICH IS DRY AND PROGRESSIVELY COOLER ACROSS THE AREA. THE ECMWF DOES NOT DEEPEN THE COLD FRONT/S PARENT LOW...AND EJECTS ITS QUICKLY EASTWARD MORE AS AN OPEN WAVE. THIS ALLOWS FOR A QUICKER RETURN OF ZONAL FLOW TO THE AREA THAT HAVE THE POTENTIAL TO BRING CENTRAL U.S. SYSTEMS INTO OR TOWARD THE AREA BY THE END OF THE WEEKEND...ALONG WITH HAVING A MILDER PATTERN. OUR FORECAST WILL REFLECT THE GUIDANCE PROVIDED BY WPC WHICH LEANS MORE CLOSELY TO THE ECWMF SOLUTION. && .AVIATION /16Z MONDAY THROUGH FRIDAY/...
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AS OF 1210 PM EDT MONDAY... WIDESPREAD VFR CONDITIONS WITH NO FLIGHT RESTRICTIONS ARE EXPECTED TO CONTINUE THROUGH TONIGHT AS SURFACE HIGH PRESSURE CURRENTLY OVER THE MID ATLANTIC STATES MOVES SLOWLY OFFSHORE. WILL SEE SOME INCREASE IN MID CLOUDS AND PERHAPS SOME STRATO-CU OVER SE WEST VA LATE TONIGHT BUT STILL DRY OVERNIGHT. A COLD FRONT WILL APPROACH FROM THE WEST BY EARLY TUESDAY AND PASS ACROSS THE AREA ON TUESDAY...LIKELY PRECEDED AND ACCOMPANIED BY SCATTERED SHOWERS/THUNDERSTORMS ALONG WITH LOCALIZED MVFR FLIGHT RESTRICTIONS. HOWEVER APPEARS THE BEST SHOT AT SEEING MVFR CIGS AND/OR VSBYS SHOULD BE OVER BLF/LWB WITH ONLY LIGHTER SHOWERS OUT TO THE BLUE RIDGE TUESDAY MORNING...FOLLOWED BY REDEVELOPMENT OF MORE ISOLATED SHRA/TSRA ALONG THE LYH-DAN CORRIDOR TUESDAY AFTERNOON. THEREFORE ONLY ADDED MVFR CIGS TO THE SE WVA LOCATIONS WITH INCLUSION OF VFR VSBY RESTRICTIONS THERE AS WELL. THE FRONT WILL EXIT THE REGION BY TUESDAY NIGHT...RESULTING IN A RETURN TO VFR WEATHER AND GUSTY NW WINDS TUESDAY NIGHT INTO WEDNESDAY...EXCEPT FOR THE POTENTIAL OF SOME MVFR CIGS LINGERING OVER THE FAR WESTERN UPSLOPE SITES IN SE WEST VA. EXTENDED AVIATION DISCUSSION... HIGH PRESSURE WILL THEN BUILD INTO AND OVER THE REGION ON THURSDAY...WITH WIDESPREAD VFR LIKELY. ANOTHER FAST MOVING COLD FRONT WILL ARRIVE ON FRIDAY...WITH A BRIEF PERIOD OF MVFR RESTRICTIONS POSSIBLE AS SHOWERS/ISOLATED STORMS MOVE EAST WITH THE FRONT THROUGH THE AREA.
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&& .FIRE WEATHER... AS OF 935 AM EDT MONDAY... LOW HUMIDITY WILL AGAIN BE AN ISSUE THROUGH THIS AFTERNOON AS HEATING AND ONLY GRADUAL MOISTURE RETURN SET THE STAGE FOR LEVELS TO FALL BELOW 25-30 PERCENT AGAIN...AND PERHAPS AS LOW AS 15 PERCENT OVER THE MOUNTAINS. HOWEVER WINDS WILL BE MUCH LIGHTER THAN THOSE SEEN ON SUNDAY WITH A GRADUAL INCREASE TO AROUND 10 MPH FROM THE WEST AND SOUTHWEST LATER IN THE AFTERNOON. ALTHOUGH THE LOW HUMIDITY WILL ALLOW FOR EXCELLENT DRYING THIS AFTERNOON... LIGHT AND ERRATIC WINDS MAY POSE SOME TRANSPORT ISSUES FOR SCHEDULED PRESCRIBED BURNS DUE TO THE VARIABILITY OF THE LOW LEVEL FLOW. ADDITIONAL OPPORTUNITIES FOR PRESCRIBED BURNS WHERE GOOD DRYING CONDITIONS WILL EXIST...AND WHERE TRANSPORT WINDS WILL BE MORE FAVORABLE DUE TO BETTER TRANSPORT AND CONSISTENCY OF DIRECTION WILL OCCUR LATE WEDNESDAY AFTERNOON...WITH AN EVEN MORE OPTIMAL CONDITION EXPECTED ON THURSDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/WERT NEAR TERM...JH/WERT SHORT TERM...DS LONG TERM...DS AVIATION...JH/RAB/WERT FIRE WEATHER...JH/WERT

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