Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 311943 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 343 PM EDT MON AUG 31 2015 .SYNOPSIS... AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL STRENGTHEN OVER THE APPALACHIANS AND CENTRAL MID ATLANTIC REGION...KEEPING US IN A RATHER STAGNANT PATTERN WITH A CHANCE FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE OF THE WORKWEEK. && .NEAR TERM /THROUGH TUESDAY/... AS OF 330 PM EDT MONDAY... THE SHORT WAVE WHICH BROUGHT PRECIPITATION TO THE REGION LAST NIGHT HAS PULLED OFF TO OUR EAST...ALLOWING THE UPPER LEVEL RIDGE TO REBUILD AND KEEP US IN A WARM AND MOIST ENVIRONMENT WITH LITTLE IN THE WAY OF DYNAMIC ENERGY TO FOCUS CONVECTIVE DEVELOPMENT. THUS... WIDELY SCATTERED SHOWERS THAT HAVE DEVELOPED THIS AFTERNOON WILL BE FADING BY EARLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. SATELLITE IMAGES SHOW THAT MID AND HIGH CLOUDS WHICH HAVE BEEN OVER THE REGION FOR THE PAST SEVERAL DAYS HAVE DIMINISHED WHICH SHOULD ALLOW FOR GOOD COOLING OVERNIGHT. COMBINED WITH A MOIST AIRMASS IN PLACE WE CAN EXPECT AREAS OF FOG TO DEVELOP TOWARD DAYBREAK...ESPECIALLY IN THE VALLEYS WEST OF THE BLUE RIDGE. LOW TEMPERATURES WILL RANGE FROM THE MIDDLE 60S ACROSS THE PIEDMONT TO AROUND 60 WEST OF THE RIDGE. ANY FOG AND LOW CLOUDS WILL DISSIPATE AFTER DAYBREAK ON TUESDAY AND MORE DIURNAL SHOWERS/POSSIBLY A RUMBLE OF THUNDER WILL DEVELOP DURING THE AFTERNOON...MAINLY FROM THE BLUE RIDGE WEST WHERE OROGRAPHIC EFFECTS CAN INITIATE CONVECTION. EVEN WITH PRECIPITABLE WATER VALUES WELL OVER ONE INCH IT WILL BE HARD TO GENERATE ANY HEAVY DOWNPOURS DUE TO THE LACK OF INSTABILITY AND DYNAMIC SUPPORT. HIGH TEMPERATURES TOMORROW WILL BE NEAR 90 DEGREES EAST OF THE RIDGE AND GENERALLY IN THE LOW/MID 80S WEST. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... AS OF 330 PM EDT MONDAY... MODELS WERE CONSISTENT SHOWING A SHORT WAVE OVER THE OHIO VALLEY TRACKING THROUGH THE MID ATLANTIC STATES ON WEDNESDAY. THIS FEATURES WILL HELP RE-ENFORCE A SURFACE COASTAL TROUGH THAT WILL EXTEND FROM NEW JERSEY TO EASTERN NORTH CAROLINA ON WEDNESDAY NIGHT. BEHIND THIS SHORT WAVE ON WEDNESDAY NIGHT AND THURSDAY 850 WINDS INCREASE TO AROUND 15 KNOTS FROM THE NORTH-NORTHWEST. WITH THE LACK OF ANY FORCING ON THURSDAY...BEST PROBABILITY OF PRECIPITATION WITH RETURN BACK TO THE TYPICAL AFTERNOON AND EVENING TERRAIN ENHANCED LOW CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS. LITTLE TO NO CHANGE IN THE AIR MASS IS EXPECTED THROUGH THE PERIOD. DEW POINTS WILL BE WELL INTO 60S FOR MOST LOCATIONS WHICH WILL KEEP LOWS MILD. HIGH TEMPERATURES WILL BE AT OR SLIGHTLY ABOVE NORMAL AND...AS ALWAYS...WILL BE HIGHLY DEPENDENT ON THE AMOUNT OF CLOUD COVER. GUIDANCE WAS REASONABLE FOR HIGHS AND LOWS THROUGH THE PERIOD. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 330 PM EDT MONDAY... WARMER AIR ASSOCIATED WITH THE UPPER RIDGE EVENTUALLY PROGRESSES EAST INTO THE FORECAST AREA FOR FRIDAY AND SATURDAY. SURFACE HIGH PRESSURE WILL BE CENTERED OVER PENNSYLVANIA AND NEW YORK AND WILL WEDGE DOWN THE APPALACHIANS...PRODUCING EAST TO SOUTHEAST WINDS FROM THE SURFACE THROUGH AT LEAST 850 MB. SO DESPITE THE HIGHER HEIGHTS ALOFT...LOW LEVEL UPSLOPE CLOUD COVER WILL LIMIT HIGH TEMPERATURES OVER THE WEEKEND. ECMWF IS SUGGESTING SOME DRIER LOW LEVEL AIR MAY GET INTO THE EASTERN COUNTY WARNING AREA LATE SUNDAY. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... AS OF 330 PM EDT MONDAY... VARIABLE CONDITIONS AT TAF SITES THROUGH THIS FORECAST PERIOD. SATELLITE IMAGES ARE SHOWING A MAINLY VFR CU FIELD DEVELOP ACROSS THE REGION...WITH THE EXCEPTIONS BEING ACROSS THE PIEDMONT WHERE BETTER BETTER LOW LEVEL MOISTURE IS LEADING TO MVFR CIGS. THUS WILL KEEP FLIGHT CATEGORIES VFR INCLUDING AT KDAN WHERE MVFR CIGS HAVE MIXED OUT. RADAR SHOWS SOME DIURNAL CONVECTION FORMING MAINLY ACROSS THE FAR WESTERN SLOPES OF THE APPALACHIANS IN WHAT CONTINUES TO BE A STAGNANT AND WEAKLY FORCED PATTERN. EXPECT SCATTERED SHOWERS AND A FEW RUMBLES OF THUNDER TO BUBBLE UP MAINLY WEST OF THE BLUE RIDGE BEFORE FADING THE LOSS OF HEATING AFTER SUNSET. WILL GENERALLY USE VCSH TO COVER THIS ACTIVITY EXCEPT AT KLWB WHERE PREDOMINANT -SHRA WILL BE MORE REPRESENTATIVE WHERE THE ACTIVITY IS MORE CONCENTRATED. BELIEVE CLOUDS WILL SCATTER OUT EARLY TONIGHT AND WITH MODEL SOUNDINGS CONTINUING TO SHOW A MOIST PROFILE AT ALL SITES...FOG AND STRATUS FORMATION SEEMS LIKE A GOOD BET. LOOK FOR IFR VSBYS AT KBLF AND LIFR CONDITIONS AT KLWB AND KBCB BEFORE DAYBREAK. KLYH SHOULD REMAIN MVFR AND EXPECT IFR CIGS/VSBYS AT KDAN. FOG/STRATUS WILL LIFT AFTER SUNRISE TUESDAY SO EXPECT VFR CONDITIONS TOWARD THE END OF THE TAF PERIOD WITH THE NEXT ROUND OF DIURNAL CONVECTION HOLDING OFF UNTIL TUESDAY AFTERNOON. 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. && .EQUIPMENT... AS OF 400 AM EDT MONDAY... 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...MBS NEAR TERM...MBS SHORT TERM...AMS LONG TERM...AMS AVIATION...MBS/NF EQUIPMENT...CF

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