Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 300853 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 453 AM EDT TUE JUN 30 2015 .SYNOPSIS... TODAY THROUGH WEDNESDAY A COLD FRONT WILL APPROACH THE REGION. THE FRONT WILL STALL ACROSS THE AREA BY WEDNESDAY NIGHT. A SERIES OF LOWS WILL TRACK ALONG THE FRONT THURSDAY THROUGH SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 430 AM EDT TUESDAY... ISOLATED SHOWERS AND THUNDERSTORMS CONTINUED OVER THE MOUNTAINS TONIGHT. CLUSTER OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST TENNESSEE WILL MOVE INTO THE SOUTHWEST COUNTY WARNING AREA BEFORE 8AM BUT WILL DISSIPATE AS IT MOVES TOWARD THE BLUE RIDGE. CHALLENGING TO FINE TUNE WHERE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE THIS AFTERNOON AND EVENING. SHORT RANGE MODELS...INCLUDED THE LOCAL WRF...SREF AND NSSL WRK SHOWED DEVELOPMENT ALONG THE LEE TROF EAST OF THE APPALACHIANS LATE THIS AFTERNOON. ALSO EXPECT THERE MAY BE REDEVELOPMENT FROM OUTFLOW GENERATED BY THE SHOWERS AND THUNDERSTORMS IN TENNESSEE. ONCE THESE STORMS DEVELOP...STORM MOTION MAY TAKE THEM INTO THE SOUTHWEST COUNTY WARNING AREA. SHOWER AND THUNDERSTORMS WILL ALSO FORM IN THE OHIO VALLEY THIS AFTERNOON AND MAY BE ORGANIZED INTO A BROKEN LINE OF BY THE TIME THEY REACH WEST VIRGINIA OVERNIGHT. HAVE INCREASED THE PROBABILITY OF PRECIPITATION IN THE EASTERN COUNTY WARNING AREA LATE THIS AFTERNOON INTO THIS EVENING AND IN THE FAR NORTHWEST COUNTY WARNING AREA TONIGHT BASED ON THESE MODEL TRENDS. CLOUD COVER OVER THE MOUNTAINS WILL LIMIT AMOUNT OF HEATING TODAY. ENOUGH CONVECTIVE AVAILABLE POTENTIAL ENERGY AND STRONG ENOUGH MID LEVEL WINDS FOR DECENT SHEAR THIS AFTERNOON THAT LEE-TROUGH STORMS HAVE A SLIGHT RISK OF BEING SEVERE. STAYED CLOSER TO COOLER MAV/ECMWF FOR MAXIMUM TEMPERATURES IN THE WEST TODAY. LEANED TOWARD WARMER GUIDANCE IN ALL AREA FOR OVERNIGHT LOWS. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 340 AM EDT TUESDAY... BROAD TROUGH OVER THE EASTERN US WILL SLOWLY SLIDE EAST DURING THE PERIOD. A SERIES OF SHORTWAVE WILL ROTATE SOUTHEAST THROUGH THE UPPER TROUGH. ALLOWED FOR LIGHT POPS WEDNESDAY MORNING IN THE WEST WITH WEAKENING STORMS ASSOCIATED WITH UPPER DISTURBANCE. ANOTHER SHORTWAVE PIVOTS ACROSS WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING. THE DAY TWO CONVECTIVE OUTLOOK INDICATED A MARGINAL POTENTIAL FOR SEVERE THUNDERSTORMS WEST OF I77 IN OUR SOUTHWEST MOUNTAINS. HIGH TEMPERATURES WEDNESDAY WILL BE NEAR NORMAL WITH READINGS FROM THE LOWER 70S IN THE NORTHWEST MOUNTAINS TO THE UPPER 80S IN THE PIEDMONT. A DISTURBANCE WILL DROP SOUTHEAST WEDNESDAY NIGHT BRUSHING OUR WEST. PLAYED THE HIGHEST POPS IN THE WEST TAPERING OFF AS ONE HEADS EAST. LOW TEMPERATURES WEDNESDAY NIGHT WILL RANGE FROM THE UPPER 50S IN THE MOUNTAINS TO THE UPPER 60S IN THE PIEDMONT. SURFACE FRONT WILL SLIDE SOUTHWARD THURSDAY AS ANOTHER SHORTWAVE ALOFT TRAVELS FROM THE MID MS VALLEY INTO OUR REGION. MODELS ARE DIFFERENT ON THE PLACEMENT AND TIMING OF MOISTURE SURGE THURSDAY AFTERNOON INTO THURSDAY NIGHT. IN ANY CASE...THERE IS A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS SUPPORTED BY ECMWF AND GFS WITH LIKELY CHANCES IN THE WEST. THE SWODY3 PLACED A MARGINAL THREAT FOR SEVERE STORMS TO OUR SOUTHWEST. HOWEVER...THE RAIN MAY BE HEAVY AT TIMES. ELECTED TO RAISED QPF FOR FORECAST AREA ON THURSDAY. HIGH TEMPERATURES THURSDAY WILL VARY FROM AROUND 70 DEGREES IN THE WEST TO THE MID 80S IN THE EAST. DECREASED POPS THURSDAY NIGHT AND TRANSITION TO SHOWERS. LOW TEMPERATURES THURSDAY NIGHT WILL GENERALLY BE FROM AROUND 60 IN THE WEST TO THE UPPER 60S IN THE EAST. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 300 PM EDT MONDAY... THE PATTERN REMAINS THE SAME THIS PERIOD...WITH SOME RISING HEIGHTS THIS WEEKEND RETURN MORE HUMIDITY. A FRONTAL BOUNDARY/BAROCLINIC ZONE WILL REMAIN AT OR CLOSE ENOUGH BY THROUGH THE PERIOD TO NOT ALLOW FOR ONE WHOLE DAY THAT IS COMPLETELY STORM FREE. NOT EVERYONE WILL SEE RAIN...BUT THE MODELS ARE FAVORING A LIKELIHOOD FOR MORE ORGANIZED CONVECTION TO MOVE ACROSS SATURDAY...WITH DIURNAL BASED MORE FRI-SUN-MON. THE TEMPS WILL BE CLOSER TO NORMAL GIVEN THE VARIATION IN FRONTAL BOUNDARY AND CLOUD COVER FROM UPSTREAM STORMS. LOW TEMPS HOWEVER WILL GET BACK TO THE MUGGY 60S...LOWER 70S. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... AS OF 150 AM EDT TUESDAY... LOCAL RADAR INDICATED SCATTERED SHOWERS OVER THE MOUNTAINS EARLY THIS MORNING. EXPECT THESE SHOWERS TO WEAKEN AND DISSIPATE AS THEY MOVE EAST BUT HAVE STILL INCLUDED RAIN IN THE KBCB AND KBLF TAFS. CLOUD COVER WILL LIMIT FOG FORMATION AT KLWB SO ONLY HAVE MVFR FOG IN JUST BEFORE SUNRISE. SHOWERS AND THUNDERSTORMS WILL REDEVELOP THIS AFTERNOON ALONG OLD OUTFLOW BOUNDARIES AND IN THE LEE TROF EAST OF THE APPALACHIANS. LOW CONFIDENCE ABOUT WHERE THE STORMS WILL DEVELOP SO HAVE KEPT OUT OF THE TAFS EAST OF THE BLUE RIDGE FOR NOW. STORMS WILL DIMINISH WITH THE LOSS OF HEATING AFTER SUNSET. HAVE VFR CONDITIONS FORECAST FOR LATE TONIGHT. EXTENDED AVIATION DISCUSSION... THE REGION WILL BE IN A GENERAL NORTHWEST FLOW PATTERN THROUGH SATURDAY. WHILE ISOLATED TO SCATTERED SHOWERS AND STORMS CANNOT BE RULE OUT ANY OF THESE DAYS...THE BEST POTENTIAL WILL BE ON THURSDAY...THEN AGAIN LATER FRIDAY...FOLLOWED BY A THIRD POTENTIAL INCREASE IN COVERAGE ON SATURDAY AS SEPARATE SHORTWAVE TROUGHS PROGRESS TROUGH THE NORTHWEST FLOW. VFR CONDITIONS ARE EXPECTED FOR MOST OF THE AREA MUCH OF THE TIME. THE EXCEPTIONS WILL COME AS TEMPORARY DECREASES WITHIN ANY HEAVIER RAIN SHOWERS OR THUNDERSTORMS...AND THEN LATE AT NIGHT AND EARLY MORNING DUE TO RIVER OR MOUNTAIN VALLEY FOG...ESPECIALLY IN AREAS THAT RECEIVED PRECIPITATION THE DAY BEFORE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...KK LONG TERM...WP AVIATION...AMS/JH

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