Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 081746 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 146 PM EDT TUE JUL 8 2014 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY BEFORE SPILLING SLOWLY SOUTHEAST INTO THE AREA ON WEDNESDAY. THIS COMBINED WITH DAYTIME HEATING AND INCREASING MOISTURE...WILL BRING AN INCREASING THREAT FOR SHOWERS AND THUNDERSTORMS...FIRST IN THE FAR WEST LATER TODAY...AND THEN FOR MUCH OF THE AREA BY WEDNESDAY. THE FRONT WILL STRUGGLE TO CLEAR THE PIEDMONT AREAS ON THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1020 AM EDT TUESDAY... HEAT AND HUMIDITY THIS AFTERNOON AS LOW LEVEL SW FLOW ENHANCES AHEAD OF THE APPROACHING UPSTREAM COLD FRONT THIS AFTERNOON. THIS COMBINED WITH DECENT HEATING ESPCLY EARLY ON AND 85H TEMPS AROUND +21C OUT EAST SHOULD AGAIN PUSH HIGHS INTO THE LOW/MID 90S EAST...AND 80S TO PERHAPS CLOSE TO 90 IN SPOTS NEAR THE BLUE RIDGE. HOWEVER STILL WELL BELOW ANY ADVISORY HEADLINES WITH DEWPOINTS AGAIN MIXING LOWER UNDER THE GUSTY SW BREEZE LATER ON. OTRW MAIN CONCERN REMAINS WITH CONVECTIVE COVERAGE ESPCLY VERY LATE THIS AFTERNOON OVER THE FAR WEST AS MODELS SUGGEST AT LEAST A BROKEN LINE OF STORMS WELL IN ADVANCE OF THE BOUNDARY DROPPING SE INTO THE AREA. THIS LOOKS TO AFFECT MAINLY THE SE WVA COUNTIES DOWN TO JUST WEST OF I-77 AFTER 20-22Z/4-6PM OR SO...WITH QUESTIONS TO JUST HOW FAR EAST OR SE THESE STORMS MAY GO GIVEN BEST SUPPORT TO THE NORTH WITH THE UPPER TROF...AND WINDS BACKING TO THE WEST. IF STORMS REDEVELOP ENOUGH TO HAVE AN ORGANIZED COOL POOL...THERE IS JUST ENOUGH INSTABILITY TO BRING SOME OF THIS COVERAGE EAST TO THE BLUE RIDGE AND PERHAPS EAST OF THE MOUNTAINS IN A WEAKENED STATE MAINLY AFTER SUNSET. THIS SUPPORTED MORESO BY THE LATEST NAM/CMC AND SPC WRF AND LESS BY THE GFS WITH THE ECMWF IN BETWEEN. INCREASING UNIDIRECTIONAL FLOW ALOFT AND HIGH FORECAST DCAPES WOULD SUPPORT MORE OF A WIND THREAT AND SEEN VIA THE CURRENT SWODY1. THUS BUMPED UP LIKELY POPS A BIT MORE WESTERN THIRD AND ADDED GUSTY WIND MENTION...WITH A SHARP CUTOFF TO SLIGHT POPS OR LESS OUT EAST THIS AFTERNOON. ANYTHING AHEAD OF THIS LINE WOULD FEATURE MOSTLY ISOLATED THUNDERSTORMS. FRONT WILL STILL BE WEST OF THE MOUNTAINS OVERNIGHT AS A WEAK WAVE HANGS IT UP AND HELPS FOCUS BEST CONVERGENCE ACROSS THE SW CWA UNDER DEEPENING WESTERLY FLOW. THIS SHOULD PIN THE NEXT ROUND OF HIGHER POPS ACROSS THE MTN EMPIRE AREA INTO NW NC OVERNIGHT WITH AGAIN A QUICK DROPOFF IN COVERAGE HEADING EAST PER DOWNSLOPE LIMITING SHRA EAST OF THE BLUE RIDGE AFTER MIDNIGHT. OTRW MOSTLY CLOUDY WEST TO PC ELSW BUT MUGGY WITH LOWS MOSTLY MID 60S VALLEYS TO LOW/MID 70S EAST. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 310 AM EDT TUESDAY... A BROAD UPPER LEVEL TROUGH WILL ENCOMPASS THE NORTHEAST QUARTER OF THE UNITED STATES...FROM THE NORTH AND CENTRAL PLAINS TO THE CAROLINAS AND MID ATLANTIC REGION...WEDNESDAY AND THURSDAY. A SURFACE FRONT WILL SLIDE ACROSS THE FORECAST AREA WEDNESDAY...STALLING ACROSS THE CAROLINAS WEDNESDAY NIGHT. THIS FRONT WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS TO THE AREA WEDNESDAY. 00Z MODEL SOLUTIONS FOR WEDNESDAY ARE QUITE DIFFERENT FROM 24 HOURS AGO. LATEST SOLUTIONS LIMITING STRONG STORMS WITH MORE MORNING RAIN AND CLOUDS OVER THE AREA. BULK OF THE STRONGER DYNAMICS AND STORMS APPEARS TO BE MOVING SOUTH INTO THE TENNESSEE VALLEY. THE FRONT BUCKLES TO THE NORTHWEST ON THURSDAY AS A WEAK REFLECTION TRACKS ALONG THE STALLED BOUNDARY ACROSS THE CAROLINAS. IF THIS BOUNDARY DOES BUCKLE...AREAS EAST OF THE BLUE RIDGE...PARTICULARLY SOUTHSIDE...WILL SEE ANOTHER ROUND OF PASSING SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON AND NIGHT. MORNING CLOUDS AND RAIN SHOULD KEEP MOUNTAIN TEMPERATURES NEAR NORMAL...WHILE THE PIEDMONT SEES WARMER THAN NORMAL TEMPERATURES WEDNESDAY. WITH MOST AREAS RESIDING BEHIND THE FRONT ON THURSDAY...TEMPERATURES WILL RUN COOLER THAN NORMAL. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 300 PM EDT MONDAY... UPPER PATTERN IS AGAIN BECOMING ZONAL THURSDAY NIGHT AND FRIDAY BUT MODELS WERE BRINGING A SHORT WAVE THROUGH THE BASE OF THE EASTERN TROF AND ACROSS THE MID ATLANTIC REGION THURSDAY NIGHT. THE 500 MB TROF DEEPENS AGAIN ON SUNDAY AND MONDAY. SURFACE FRONT IS WELL TO THE SOUTHEAST OF THE FORECAST AREA THURSDAY NIGHT AND FRIDAY BUT ANY WAVE ALONG THE FRONT MAY BRING DEEPER MOISTURE AND A HIGHER PROBABILITY OF PRECIPITATION BACK TOWARD THE SOUTHERN COUNTY WARNING AREA. FORECAST AREA WILL RETURN TO WARM...HUMID...UNSTABLE AIR...AND THE ASSOCIATED CHANCE OF THUNDERSTORMS...SUNDAY AND MONDAY AHEAD OF THE NEXT COLD FRONT. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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AS OF 145 PM EDT TUESDAY... COMMS ISSUES REMAIN AT KDAN DESPITE AN INTERMITTENT RETURN OF OBSERVATION DATA. AMD NOT SKED CONTINUED IN THE TAF. BAND OF SHOWERS AND THUNDERSTORMS WILL FORM FROM WESTERN PENNSYLVANIA TO EASTERN KENTUCKY AND MOVE EAST DURING THE EVENING. LAST FEW RUNS OF THE HRRR...AS WELL AS THE RUC AND LOCAL WRF HAVE THE STORMS REACHING KBLF AND KBLF FROM 20-21Z/4-5PM. LOWER CONFIDENCE AS TO HOW FAR EAST SHOWERS AND THUNDERSTORMS WILL PROGRESS. HAVE LEFT VCNTY THUNDER IN THE KBCB...KROA AND KLYH TAFS. THE LEAST LIKELY LOCATION TO GET STORMS WILL BE AT KDAN AS LONG AS SCATTERED TO ISOLATED THUNDERSTORMS DO NOT DEVELOP IN THE FOOTHILLS OF THE BLUE RIDE. AS LOWER DEW POINTS MIX DOWN TO THE SURFACE THIS AFTERNOON...THE INSTABILITY WAS BECOMING LESS FAVORABLE FOR THUNDERSTORMS IN THE LEE-TROF. LOSS OF HEATING AND WESTERLY DOWNSLOPE WIND WILL WEAKEN SHOWERS AND THUNDERSTORMS BY 02Z/10PM. MODELS SHOWED LINGERING SHOWERS FROM SOUTHERN WEST VIRGINIA TO EASTERN TENNESSEE OVERNIGHT. DO NOT HAVE ANY IMPACT FROM THIS POTENTIAL RAINFALL IN THE TAFS BUT HAVE ADDED MVFR CEILINGS TO KBLF AFTER MIDNIGHT. ALSO ADDED LIFR FOG AND CEILINGS IN FOR KLWB OVERNIGHT..EXPECTING THERE WILL BE RAIN AT THAT AIRPORT LATE THIS AFTERNOON. EXTENDED AVIATION... BEST CHANCE FOR THUNDERSTORMS ON WEDNESDAY WILL BE IN THE AFTERNOON IN CENTRAL AND EASTERN VIRGINIA AND NORTH CAROLINA WHERE THE INSTABILITY WILL COMBINE WITH OUTFLOW FROM PREVIOUS STORMS. THE COLD FRONT WILL FINALLY PUSH THROUGH THE REGION ON WEDNESDAY NIGHT. THE FRONT WILL LINGER ACROSS SOUTHERN/EASTERN AREAS THROUGH THE END OF THE WEEK WITH IMPULSES RIDING ALONG IT. THIS WILL KEEP UNSETTLED CONDITIONS AT TAF SITES THROUGH THE END OF THE WEEK. EXPECT DIURNAL TRENDS FOR AFTERNOON CONVECTIVE PRECIPITATION WITH ASSOCIATED MVFR OR LOWER CONDITIONS... ESPECIALLY FOR KDAN/KLYH...AND POSSIBLE IFR FOG LATE NIGHTS...MAINLY KBCB AND KLWB.
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&& .EQUIPMENT... COMMS ISSUES WITH KDAN ASOS NOT TRANSMITTING. THE FAA IS AWARE OF THE OUTAGE AND WILL BE WORKING ON IT...BUT NO ESTIMATED TIME OF WHEN IT WILL BE WORKING AGAIN. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/SK NEAR TERM...AMS/JH SHORT TERM...RCS LONG TERM...AMS AVIATION...AMS/JH EQUIPMENT...WP

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