Area Forecast Discussion
Issued by NWS Blacksburg, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRNK 012003 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 403 PM EDT TUE SEP 1 2015 .SYNOPSIS... AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL STRENGTHEN OVER THE APPALACHIANS AND CENTRAL MID ATLANTIC REGION TODAY...KEEPING US IN A RATHER STAGNANT PATTERN WITH ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THROUGH LATE IN THE WEEK. A WEAK BACKDOOR COLD FRONT WILL DROP SOUTH THROUGH THE AREA BY THE WEEKEND. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 330 PM EDT TUESDAY... STARTING SEPTEMBER OFF ON THE WARM SIDE WITH AFTERNOON TEMPERATURES RANGING FROM THE LOW 80S WEST TO THE LOW 90S OVER THE PIEDMONT. SLOW MOVING SHOWERS HAVE DEVELOP WITH AFTERNOON HEATING...BUT HAVE HELD NEAR THE INTERSTATE 64 CORRIDOR FOR THE MOST PART...WITH ONLY A FEW SPRINKLES ELSEWHERE ACROSS THE MOUNTAINS. WE CAN EXPECT THESE SHOWERS TO FADE TOWARD SUNSET AS HEATING ENDS...AND EXPECT CLOUDS TO FADE AS WELL...MAKING FOR PARTLY CLOUDY SKIES ENTERING THE NIGHT. WITH DEWPOINTS EXPECTED TO HOLD IN THE 60S OVERNIGHT...LIGHT WINDS AND ONLY SCATTERED CLOUDS...PATCHY FOG APPEARS LIKELY ONCE AGAIN ACROSS THE AREA...AT LEAST DURING THE EARLY HALF OF THE NIGHT. MID AND HIGH CLOUDS WILL BEGIN TO INCREASE SHORTLY BEFORE DAWN AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE OHIO VALLEY...WHICH MAY CAUSE SOME OF THE FOG TO THIN BEFORE SUNRISE. OTHERWISE... EXPECT A MUGGY WARM NIGHT...WITH LOWS HOLDING IN THE LOW TO MID 60S AREAWIDE. ANY REMAINING FOG WILL BURN OFF QUICKLY AFTER 10 AM WEDNESDAY WITH ANOTHER DAY OF STRONG HEATING. THE UPPER LEVEL DISTURBANCE WILL DRIFT ACROSS THE NORTHERN HALF OF THE AREA DURING EARLY AFTERNOON... AND EXPECT GREATER COVERAGE OF SHOWER ACTIVITY ACROSS THE MOUNTAINS. FORECAST MODEL SOUNDINGS INDICATE THAT THERE WILL BE ENOUGH INSTABILITY PRESENT FOR A FEW OF THE SHOWERS TO INTENSIFY INTO THUNDERSTORMS DURING MID AFTERNOON. AS THE DISTURBANCE WILL BE SLOW MOVING...LINGER ACROSS OUR AREA THROUGH SUNSET. AFTERNOON HIGH TEMPERATURES WILL REACH THE UPPER 70S/LOW 80S ACROSS THE MOUNTAINS...AND CLIMB AS HIGH AS THE LOW 90S ACROSS THE SOUTHSIDE. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... AS OF 345 PM EDT TUESDAY... THE GFS MOVES THE OHIO SHORT WAVE SLOWER THAN THE NAM/SREF. GIVEN THE LACK OF A KICKER FOR THIS VORT MAX...THE SLOWER GFS SEEMS MORE REASONABLE...BUT EVEN ON THIS SLOWER TRACK THE SHORT WAVE WILL STILL BE SOUTHEAST OF THE FORECAST AREA BY THURSDAY AFTERNOON. WILL EXTEND THE PROBABILITY OF PRECIPITATION IN THE FORECAST FOR WEDNESDAY NIGHT. STAYED CLOSER TO MAV GUIDANCE THROUGH THE PERIOD. BACKDOOR FRONT MOVES SOUTH THROUGH THE NEW ENGLAND AND MID ATLANTIC COAST. MODELS WERE SHOWING SOME CONVERGENCE IN EASTERN VIRGINIA BUT STILL QUESTIONABLE HOW MUCH LIFT THIS FEATURE MAY PROVIDE FOR THE COUNTY WARNING AREA. BEST PROBABILITY OF PRECIPITATION WILL BE IN THE NORTHEAST COUNTIES OF THE FORECAST AREA...EAST OF THE BLUE RIDGE. AS THIS FRONT MOVES DOWN THE COAST AND HIGH PRESSURE BUILDS SOUTH OVER THE APPALACHIANS...WINDS WILL TURN FROM NORTH TO EAST. THIS EASTERLY COMPONENT OF THE WIND AT THE SURFACE THROUGH LOW LEVELS MAY ALSO EXPAND THE CLOUD COVER AND PROBABILITY OF PRECIPITATION ALONG THE BLUE RIDGE. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 100 PM EDT TUESDAY... LOWER 500 MB HEIGHTS REMAINED TRAPPED UNDER THE RIDGE OVER THE SOUTHEAST UNITED STATES FRIDAY NIGHT THROUGH SUNDAY. SUNDAY NIGHT INTO TUESDAY...THE CENTER OF THE UPPER RIDGE...DRIFTS SOUTH INTO THE MID ATLANTIC REGION. HEIGHTS WILL BE CLOSE TO 594DM ACCORDING TO THE 00Z GFS. AT THE SURFACE FRIDAY NIGHT ANY REMNANTS OF THE BACKDOOR FRONT WASH OUT AND BY SATURDAY THE WEDGE WILL BE FULLY ESTABLISHED AND THIS FEATURE WILL REMAIN IN PLACE THROUGH SUNDAY. HIGH PRESSURE WILL COVER THE MID ATLANTIC STATES THROUGH TUESDAY. UNSEASONABLY WARM TEMPERATURES...WITH 850 MB TEMPERATURES APPROACHING +20...MOVE INTO THE REGION WITH THE HIGHER HEIGHTS. A DRIER AIR MASS BEGINS TO APPROACH THE REGION AS THE WEDGE BUILDS IN ON SATURDAY. SUNDAY AND MONDAY...ECMWF WAS SHOWING MUCH DRIER AIR ABOVE 850MB. BELOW 850 MB THE DRIER AIR REMAINS EAST AND SOUTH OF THE FORECAST AREA THROUGH MONDAY. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... AS OF 200 PM EDT TUESDAY... VFR CONDITIONS REPORTED AREAWIDE THIS AFTERNOON UNDER A CU FIELD... SCT ACROSS THE PIEDMONT AND SCT TO BKN ACROSS THE MOUNTAINS...WITH BASES IN THE 4KFT TO 6KFT RANGE. RADAR INDICATES A FEW SHOWERS HAVING DEVELOPED ALONG A KLWB TO KHSP LINE...WHICH ARE SLOW MOVING AND PRODUCING LIGHT TO LOCALLY MODERATE RAINFALL. SPOTTY SHOWERS WILL CONTINUE TO DEVELOP ACROSS THE MOUNTAINS THIS AFTERNOON...WITH BEST CHANCES ALONG THE RIDGES OF SOUTHEAST WEST VIRGINIA. INDIVIDUAL SHOWERS WILL REMAIN SMALL AND HAVE LIMITED IMPACTS ON VISIBILITY BENEATH...BUT WILL MOVE SLOWLY...WHICH MAY CAUSE THEM TO LINGER FOR AN EXTENDED PERIOD OF TIME. INSTABILITY IS EXPECTED TO REMAIN LIMITED...AND THEREFORE ANY THUNDERSTORM ACTIVITY SHOULD REMAIN ISOLATED AND SHORT LIVED. CONVECTION WILL FADE TOWARD SUNSET. OVERNIGHT...SCATTERED MID LEVEL CLOUDS WILL MOVE INTO THE AREA AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE OHIO VALLEY. REGARDLESS...EXPECT PATCHY FOG TO REDEVELOP...WITH VISIBILITIES ACROSS MUCH OF THE FORECAST REGION FALLING INTO THE 3SM TO 5SM RANGE...AND AS LOW AS 1/2SM IN SOME OF THE DEEPER RIVER VALLEYS. CEILINGS MOST LOCATIONS ARE EXPECTED TO REMAIN ABOVE 3KFT. FOG WILL DISSIPATE QUICKLY AFTER 02/14Z...AND ANY LOW CLOUDS WILL GRADUALLY LIFT. SCATTERED SHOWERS WILL ENTER THE MOUNTAINS DURING LATE MORNING AS THE UPPER LEVEL DISTURBANCE DRIFTS SLOWLY ACROSS THE NORTHERN HALF OF THE AREA. WITH GREATER INSTABILITY ON WEDNESDAY...EXPECT A FEW SHOWERS TO INTENSIFY INTO THUNDERSTORMS DURING MID AFTERNOON AND THE EVENING. THE DISTURBANCE WILL BE SLOW MOVING...SO CONVECTION WILL LINGER ACROSS THE PIEDMONT AFTER SUNSET. EXTENDED AVIATION DISCUSSION... THE FORECAST AREA WILL REMAIN IN A WEAKLY FORCED SYNOPTIC ENVIRONMENT THROUGH MIDWEEK...WITH CHANCES FOR DIURNAL CONVECTION MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR FOG/STRATUS DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB. FOR FRIDAY INTO SATURDAY WILL SEE HIGH PRESSURE IN CONTROL THOUGH THE POSITION OF THE HIGH OVER THE MID ATLANTIC MAY SLIDE MORE MVFR CIGS OFF THE ATLANTIC INTO OUR EASTERN TAF LOCATIONS. && .EQUIPMENT... AS OF 400 PM EDT TUESDAY... THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT. AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...NF NEAR TERM...NF SHORT TERM...AMS LONG TERM...AMS AVIATION...JH/NF EQUIPMENT...

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.