Area Forecast Discussion
Issued by NWS Blacksburg, VA

Current Version | Previous Version | Text Only | 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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRNK 212301 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 701 PM EDT TUE MAY 21 2013 .SYNOPSIS...
-- Changed Discussion --
AN UPPER LEVEL AREA OF LOW PRESSURE WILL DRIFT EAST AND OFFSHORE OVERNIGHT. A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT THROUGH THE AREA THURSDAY...FOLLOWED BY HIGH PRESSURE ON FRIDAY.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH WEDNESDAY/... AS OF 310 PM EDT TUESDAY... SATELLITE LOOP SHOWED SCATTERED CU DEVELOPING THIS AFTERNOON ESPECIALLY ACROSS THE HIGHER TERRAIN. REGIONAL WSR-88D LOOP DISPLAYED ISOLATED CONVECTION FORMING JUST SOUTHEAST OF CWA ACROSS EASTERN PORTIONS OF VIRGINIA AND NORTH CAROLINA IN THE MOIST AND UNSTABLE AIR. RNK WRF ARW AND RUC INDICATED THAT THE BEST CHANCE FOR THUNDERSTORMS THIS AFTERNOON INTO TONIGHT WILL OCCUR ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS. THE NAM AND GFS FOCUS ON CONVECTION THIS EVENING INTO TONIGHT IN THE WEST AND NORTHWEST. INCREASED POPS THIS EVENING IN THE NORTHWEST ALLOWING FOR MENTION OF LIKELY FOR SOUTHEAST WEST VIRGINIA WITH BEST SFC MOISTURE CONVERGENCE AND MID LVL OMEGA FIELDS. SOME OF THE STORMS TONIGHT COULD CONTAIN HEAVY DOWNPOURS...HAIL AND GUSTY WINDS. WITH THE LOSS OF SOLAR HEATING...CONVECTION WILL WEAKEN AND TAPER OFF AFTER MIDNIGHT. WENT WITH LOW TEMPERATURES CLOSE TO MILD ADJMAV WITH VALUES FROM THE MID 50S IN THE MOUNTAINS TO THE MID 60S IN THE SOUTHEAST. WARM AND HUMID CONDITIONS CONTINUE ON WEDNESDAY IN THE SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. INCREASED POPS FROM WEST TO EAST ON WEDNESDAY...WITH HIGHEST POPS ALONG WESTERN MOUNTAINS. THE SWODY2 (DAY TWO CONVECTIVE OUTLOOK) HAS THE SLIGHT RISK JUST TO OUR WEST ON WEDNESDAY. PLAYED HIGHS TEMPERATURES COOLER ON WEDNESDAY WITH READINGS FROM THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... AS OF 255 PM EDT TUESDAY... HAVE A COUPLE DAYS MORE OF HUMID WEATHER BEFORE FRONT SWINGS ACROSS THURSDAY AND BRINGS A RETURN TO LOWER DEWPOINTS. UNTIL THEN...NO MAJOR CHANGES TO THE FORECAST. WEDNESDAY NIGHT A PIECE OF SHORTWAVE ENERGY ARRIVES ACROSS THE CENTRAL APPALACHIANS WHICH CREATES AN AREA OF SHOWERS AND STORMS...MAINLY AFFECTING THE WRN EDGE OF THE FORECAST AREA. THE BETTER PUSH OF THE FRONT ON THURSDAY COMBINED WITH BETTER UPPER SUPPORT SHOULD BRING SOME ENHANCED THREAT OF SHOWERS AND STORMS. TIMING OF THIS FRONT DOES VARY SOMEWHAT FROM THE MODELS BUT ENOUGH AGREEMENT TO HAVE HIGH CHANCE TO LIKLEY IN THE AREA THURSDAY. TIMING ALSO GIVES ISSUES TO SVR THREAT. ATTM...EXPECT A LINE OF SHRA/TSRA TO BE IN THE MTNS IN THE MORNING AND MOVING INTO THE PIEDMONT BY EARLY AFTERNOON. NOT SEEING A LOT OF HEATING AS CLOUDS WILL BE GENEROUSLY SPREAD. ONE AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF VA/NC. THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO THE LOWER TO MID 70S EAST. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 PM EDT TUESDAY FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY THE END OF THE PERIOD. WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING. THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING SOAKED AGAIN MONDAY-WEDNESDAY. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
AS OF 645 PM EDT TUESDAY... CONVECTION REMAINS QUITE ISOLATED ACROSS THE REGION THIS EVENING WITH MOST COVERAGE OVER NW NORTH CAROLINA WELL SW OF THE TAF SITES. MAIN CONCERN WILL BE WITH THE COMPLEX OF SHRA/TSRA ASSOCIATED WITH AN OLD OUTFLOW HEADING NE OUT OF TN/KY DURING THE NEXT FEW HOURS. LATEST SHORT RANGE GUIDANCE BRINGS SOME OF THIS AS FAR EAST AS THE BLUE RIDGE AROUND MIDNIGHT BEFORE IT FADES. THUS MAY HAVE A STORM OR SHRA AFFECT KBLF/KLWB DURING THE LATE EVENING ...WITH A BAND/CLUSTER OF SHRA/TSRA NEAR KBCB/KROA TOWARD MIDNIGHT PENDING HOW FAR EAST THE PRECIP MAKES IT AFTER LOSS OF HEATING AND LITTLE UPPER SUPPORT. GIVEN UNCERTAINTY WILL COVER MAINLY WITH VCTS/VCSH FOR NOW AND AMEND IF STORMS DO INDEED GET CLOSER. OTHER CONCERN AGAIN WITH FOG LATE ESPCLY NEAR WHERE ANY RAINFALL OCCURS GIVEN SUCH A MUGGY ENVIRONMENT. LATEST FORECAST RAOB SOUNDINGS SUGGEST QUITE A BIT OF PATCHY FOG BUT LIKELY NOT AS WIDESPREAD AS THIS MORNING EXCEPT IN SPOTS WHERE A SHRA PASSES. REGARDLESS OF SHRA COVERAGE...APPEARS KLWB STILL HAS THE BEST CHANCE TO DROP TO LIFR IN FOG WEDNESDAY MORNING WITH A PERIOD OF IFR ELSW EXCLUDING KBLF/KROA WHERE ONLY BRIEF MVFR POSSIBLE AT THIS TIME. EXPECT A QUICK IMPROVEMENT TO CONDITIONS ON WEDNESDAY WITH THE ONSET OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER SCTD/BKN 5-6K FT CU FIELDS. THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY. THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG. HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT.
-- End Changed Discussion --
&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/KK SHORT TERM...WP LONG TERM...WP AVIATION...AMS/JH/KK

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