Area Forecast Discussion
Issued by NWS Blacksburg, VA

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822 FXUS61 KRNK 040001 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 801 PM EDT TUE MAY 3 2016 .SYNOPSIS... OUR WEATHER WILL REMAIN COOL AND UNSETTLED THROUGH THE END OF THE WORKWEEK...WITH WEAK DISTURBANCES MOVING THROUGH THE REGION AND BRINGING US A CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 330 PM EDT TUESDAY... EARLY CLOUDS GAVE WAY TO SOME SUN WHICH ALLOWED DIURNAL INSTABILITY TO SET UP AN ENVIRONMENT CONDUCIVE FOR THUNDERSTORM DEVELOPMENT. THE STORMS GOT STARTED WEST OF THE BLUE RIDGE AND HAVE NOW MOVED TO THE EAST WHERE THERE IS BETTER INSTABILITY. WITH COOL TEMPERATURES ALOFT AND PWATS OVER ONE INCH ACROSS THE PIEDMONT EXPECT LOCALLY HEAVY RAIN AND SOME HAIL WITH AN ISOLATED SEVERE THREAT SOUTHSIDE/PIEDMONT... WITH THE BEST SUPPORT FOR MORE WIDESPREAD SEVERE CONVECTION RESIDING FURTHER TO THE SOUTH AND EAST OUTSIDE OF OUR AREA. EXPECT THE BULK OF ACTIVITY TO BE EXITING THE REGION TO THE EAST EARLY THIS EVENING BUT SOME SCATTERED SHOWERS/STORMS WILL BE FLOATING AROUND FURTHER WEST AS WELL. THE ACTIVITY WILL DWINDLE OVERNIGHT AS THE LINGERING COLD FRONTAL BOUNDARY SINKS FURTHER TO THE SOUTH BUT AS A SHORT WAVE APPROACHES LATE TONIGHT A RESURGENCE OF SCATTERED ACTIVITY IS EXPECTED FAR WEST OF THE BLUE RIDGE. WEDNESDAY WILL REMAIN UNSETTLED WITH MORE SHORT WAVE ENERGY ROTATING IN OUR DIRECTION. AS TEMPERATURES CONTINUE TO COOL ALOFT LAPSE RATES SHOULD BE STEEP ENOUGH TO COMBINE WITH SOME DIURNAL INSTABILITY TO GENERATE SOME SHOWERS/ISOLATED THUNDERSTORMS FROM LATE MORNING ON. HIGHS ION WEDNESDAY WILL BE ON THE COOL SIDE WITH READINGS IN THE LOWER 70S EAST TO 60/65 WEST. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... AS OF 330 PM EDT TUESDAY... UPPER LEVEL PATTERN SUPPORTS DEVELOPMENT OF AN OMEGA BLOCK WITH CUTOFF LOWS ON THE EAST AND WEST COASTS OF THE CONUS...A HIGH AMPLITUDE RIDGE IN-BETWEEN. PATTERN TRANSITION WILL TAKE PLACE WEDNESDAY AND WEDNESDAY NIGHT AS A COLD UPPER LEVEL TROUGH SINKS SOUTH FROM HUDSON BAY REGION THROUGH THE GREAT LAKES AND OHIO VALLEY. THIS TROUGH WILL CUTOFF OVER THE MID ATLANTIC THURSDAY...AND THEN STALL VCNTY OF THE MID-ATLANTIC COAST FOR FRIDAY. SPOKES OF VORTICITY WILL BE SPIRALING AROUND THE UPPER LOW...EACH VORT AXIS PROVIDING DYNAMIC LIFT FOR SHOWERS. AS SUCH...EXPECTING PERSISTENT UNSETTLED WEATHER DURING THIS PERIOD OF THE FORECAST WITH CONSIDERABLE CLOUDINESS AND THE THREAT OF SHOWERS. TEMPERATURES WILL STRUGGLE PER ABUNDANT CLOUD COVER...SHOWERS...AND COLD POOL ALOFT. FORECAST 85H TEMPS OF 0 TO +5 DEGREES C SUGGEST WE WILL BE UNSEASONABLY COOL WITH SFC TEMPERATURES 10 TO 15 DEGREES BELOW NORMAL. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 330 PM EDT TUESDAY... CUTOFF LOW VCNTY OF THE MID ATLANTIC COAST EARLY SATURDAY WILL BEGIN TO WEAKEN AND DRIFT EAST THIS WEEKEND AS FLOW ALOFT SLOWLY EVOLVES INTO A MORE PROGRESSIVE PATTERN FOR THE SECOND WEEK OF MAY. THE WEEKEND WILL BE OUR TRANSITION BETWEEN THE TWO PATTERNS SO LOOK FOR SATURDAY TO BE THE COOLER OF THE TWO DAYS. WARM AIR ADVECTION WILL FINALLY WIN OUT BY SUNDAY WITH TEMPERATURES FAVORING THE WARMER SIDE OF NORMAL FOR SUNDAY AND INTO THE FIRST PART OF NEXT WEEK. MODELS STILL HANG ONTO SOME LINGERING CLOUDS SATURDAY...BUT THINK SUBSIDENCE IN THE WAKE OF THE UPPER LOW SHOULD FAVOR MAINLY DRY CONDITIONS. MODELS BRING ANOTHER FRONT INTO THE AREA FROM THE NORTHWEST SUNDAY...THIS FEATURE STALLING SOUTH OF THE REGION SUNDAY NIGHT BEFORE RETURNING AS A WARM FRONT MONDAY INTO TUESDAY. MOISTURE CONVERGENCE ALONG THIS FRONT WILL RESULT IN A RISK FOR SHOWERS DURING THE PERIOD...BUT NOT CONFIDENT ON TIMING OR AMOUNTS ATTM. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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AS OF 750 PM EDT TUESDAY... ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO GRADUALLY DISSIPATE THIS EVENING. COVERAGE WILL BE TOO LIMITED TO INCLUDE IN THE BODY OF THE TAFS. WINDS WERE OUT OF THE WEST TO NORTHWEST ACROSS THE MOUNTAINS THIS EVENING. EXPECT STRIP OF MVFR STRATOCUMULUS ON THE WEST SLOPES OF THE APPALACHIANS THROUGH WEDNESDAY MORNING. HIGH CONFIDENCE THAT KBLF WILL LOWER TO MVFR BY MIDNIGHT THEN REMAIN AROUND 2000 FT THROUGH SUNRISE. KLWB WAS ON THE EASTERN EDGE OF THESE LOWER CLOUDS. MEDIUM CONFIDENCE THERE WILL BE ENOUGH OF A BREAK IN THE CLOUD COVER AND ENOUGH LOW LEVEL MOISTURE FOR LIFR FOG TO DEVELOP IN THE GREENBRIER RIVER VALLEY AND AT KLWB OVERNIGHT. ANY STRATUS AND FOG WILL DISSIPATE QUICKLY WEDNESDAY MORNING. A SHORT WAVE TRACKING INTO THE MID ATLANTIC REGION LATE IN THE DAY WILL BRING COLDER TEMPERATURES ALOFT...LEADING TO SCT-BKN VFR STRATOCUMULUS IN THE AFTERNOON. EXTENDED AVIATION DISCUSSION... A CLOSED UPPER LOW WILL DEVELOP BY WEDNESDAY NIGHT AND WILL REMAIN OVER THE MID ATLANTIC STATES FOR MUCH OF THE WEEK. CONDITIONS SHOULD BE EXPECTED TO BE MVFR OR WORSE FOR MUCH OF THE REMAINDER OF THE WEEK DUE TO PERIODIC SHOWERS AND ISOLATED THUNDERSTORMS WHICH WILL RESULT IN LOWS CIGS....AND FOG. SATURDAY COULD BE A DRY BREAK BETWEEN SYSTEMS BUT CONFIDENCE IS LOW.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...MBS NEAR TERM...MBS SHORT TERM...PM LONG TERM...PM AVIATION...AMS/JR

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