Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 060023 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 823 PM EDT SUN JUL 5 2015 .SYNOPSIS... AN UPPER LOW OVER WEST VIRGINIA WILL SLOWLY LIFT NORTHEAST TONIGHT AND REACH WESTERN PENNSYLVANIA BY LATE MONDAY. THIS SYSTEM WILL CREATE SHOWERS AND THUNDERSTORMS FOR OUR REGION. A COLD FRONT WILL MOVE INTO THE AREA FROM THE OHIO VALLEY BY WEDNESDAY...THEN STALL AND LIFT BACK NORTH AS A WARM FRONT LATE IN THE WEEK...AS HIGH PRESSURE ALOFT BUILDS ACROSS THE SOUTHEAST STATES. SCATTERED SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE FRONT. BELOW NORMAL TEMPERATURES EARLY IN THE WEEK WILL MODERATE TO ABOVE NORMAL TEMPERATURES BY THE END OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... AS OF 650 PM EDT SUNDAY... FLASH FLOOD WATCH REMAINS IN EFFECT FOR FAR WEST THROUGH TONIGHT. THERE REMAINS THE POTENTIAL FOR HEAVY RAINS WITH CONVECTION INTO TONIGHT WITH PWATS AROUND 1.5 TO 2 INCHES...SOUTH TO SOUTHWEST FLOW AND RELATIVELY LOW FFG IN THE WEST. RAINFALL RATES...MOVEMENT AND TRAINING OF STORMS WILL BE KEY ITEMS TO MONITOR. TRAINING OF ECHOES FROM SOUTH TO NORTH OVER SATURATED GROUND WILL BE OF HIGH CONCERN. A WEST TO EAST ORIENTATION NORTH OF FRONTAL BOUNDARY COULD ALSO RESULT IN LOCAL WATER PROBLEMS DEPENDING ON LOCATION OF THE HEAVY RAIN. THE DAY ONE CONVECTIVE OUTLOOK ALSO HIGHLIGHTS THE POTENTIAL FOR MARGINAL SEVERE IN THE SOUTHEAST CORNER OF CWA WITH WIND AND HAIL THE PRIMARY THREATS. UPPER LOW OVER WAS OVER THE WEST VIRGINIA/KENTUCKY BORDER AT 23Z/7PM AND WILL LIFT NORTHEAST TONIGHT AND REACH WESTERN PENNSYLVANIA BY MONDAY EVENING. SURFACE FRONTAL BOUNDARY REMAINS WEST TO EAST ACROSS THE SOUTHERN FORECAST AREA AND WILL LIFT NORTH AS WARM FRONT TONIGHT INTO MONDAY. LOW LEVEL MOISTURE POOLING IS OCCURRING ALONG THE SURFACE BOUNDARY. SOME OF THE THUNDERSTORMS WILL CONTAIN HEAVY RAINS. LEANED POPS THIS AFTERNOON INTO TONIGHT TOWARDS A BLEND OF HRRR...ARW AND CONTINUITY...THEN TRIM BACK POPS FOR THE OVERNIGHT AS MID LEVEL DRY AIR WRAPS AROUND FROM THE WEST. ADDED AREAS OF FOG OVERNIGHT WITH LIGHT WINDS AND LOW LEVEL MOISTURE. LOWS TONIGHT WILL RANGE FROM THE LOWER 60S IN THE MOUNTAINS TO NEAR 70 DEGREES IN THE PIEDMONT. CLOSED UPPER LOW WILL CONTINUE DRIFTING NORTH-NORTHEAST ON MONDAY. START WITH THE HIGHEST POPS MONDAY MORNING WITH THE WARM ADVECTION AND SHIFT POPS AXIS NORTHWARD DURING THE DAY. THE DAY TWO CONVECTIVE OUTLOOK KEEPS OUR AREA IN GENERAL THUNDERSTORMS FOR MONDAY. ANY ADDITIONAL FLOOD WATCHES FOR MONDAY WILL BE DEPENDENT ON SUNDAYS CONVECTION AND LOCATION. HIGH TEMPERATURES ON MONDAY WILL VARY FROM THE UPPER 60S IN THE NORTHWEST MOUNTAINS TO THE MID 80S IN THE PIEDMONT. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 355 PM EDT SUNDAY... FORCING FOR SHOWERS/STORMS WILL WANE MONDAY NIGHT AS UPPER SUPPORT MOVES NORTHEAST AND AWAY FROM THE REGION. DON`T BLINK. PROGRESSIVE FLOW ACROSS THE NORTHERN PART OF THE CONUS WILL INTRODUCE ANOTHER FRONT AND ASSOCIATED BAROCLINIC ZONE WHICH WILL APPROACH THE REGION TUESDAY...THEN STALL EAST-WEST ALONG THE MASON DIXON FOR MID WEEK. MODELS BRING SURFACE COLD FRONT INTO THE OHIO VALLEY FROM THE UPPER MID-WEST ON TUESDAY. LINEAR ORIENTED...POTENTIALLY STRONG CONVECTION...APPEARS LIKELY WITH THIS SYSTEM...BUT ATTM IT APPEARS THIS ACTIVITY WILL NOT REACH OUR FCST AREA UNTIL AFTER PEAK HEATING TUESDAY OR SOMETIME TUESDAY NIGHT. IF THIS TURNS OUT TO BE THE CASE THEN STRENGTH OF THE ACTIVITY SHOULD BE LESS ROBUST WITH ONLY MARGINAL RISK OF SEVERE WEATHER TO CONTEND WITH TUESDAY NIGHT...AND THEN MAINLY ALONG THE WESTERN SLOPES OF THE MOUNTAINS...THE STORMS FALLING APART AS THEY CROSS THE MOUNTAINS. FOR WEDNESDAY...THE SURFACE FRONT STALLS JUST TO OUR NORTH AS THE UPPER SUPPORT MOVES EAST IN TANDEM WITH A BUILDING SUBTROPICAL HIGH OVER THE SOUTHEAST STATES. SUBTROPICAL RIDGING WILL BLOCK SOUTHERN PROGRESSION OF FRONT...HOWEVER...CONVERGENCE OF AIRMASS OVER THE AREA WILL ALLOW FOR SCATTERED TO NUMEROUS SHOWERS/STORMS...ESP ACROSS THE NORTHERN CWA CLOSER TO THE FRONTAL BOUNDARY. TEMPERATURES BY MID WEEK WILL TREND WARMER...WITH ABOVE NORMAL READINGS ANTICIPATED PER INCREASING HEIGHTS/THICKNESSES AND A WESTERLY WIND COMPONENT WHICH SHOULD AID IN ADIABATIC WARMING EAST OF THE BLUE RIDGE. WITH 85H TEMPS APPROACHING +20 DEG C...SURFACE READING SHOULD EASILY CLIMB WELL INTO THE 80S AND POSSIBLY THE L-M 90S PENDING SUNSHINE. MINIMUM TEMPERATURES WILL ALSO AVERAGE WELL ABOVE NORMAL...THANKS TO CONTINUED HIGH MOISTURE CONTENT AND DEWPOINTS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 355 PM EDT SUNDAY... TYPICAL SUMMERLIKE WEATHER ANTICIPATED FOR THE END OF THE WEEK AND INTO NEXT WEEKEND...WITH TENDENCY FAVORING THE WARM SIDE OF GUIDANCE AS STRONG SUBTROPICAL RIDGE ALOFT ENVELOPS THE SOUTHEAST CONUS. THERE WILL BE A DAILY THREAT FOR SHOWERS/STORMS...MAINLY SCATTERED AND DIURNALLY DRIVEN. HOWEVER...WILL HAVE TO WATCH FRONTAL BOUNDARY WHICH WILL BE STALLED ACROSS THE OHIO VALLEY AND INTO THE NORTHERN MID ATLANTIC WHERE MORE ORGANIZED DEEP CONVECTION WILL TAKE PLACE...OUTFLOW FROM WHICH MAY DRIFT INTO OUR NORTHERN CWA. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 815 PM EDT SUNDAY... NUMEROUS CLUSTERS AND LINES OF SHOWERS AND THUNDERSTORMS WERE ROTATING THROUGH THE REGION...AROUND AN UPPER LOW THAT WAS CENTERED NEAR KHTS. THE THUNDERSTORMS WERE PRODUCING MVFR CEILINGS AND VISIBILITIES AND OCCASIONALLY LIFR VISIBILITIES WITH VERY HEAVY RAIN. TIMING THE IMPACT OF THE SHOWERS AND THUNDERSTORMS AT LOCAL AIRPORTS HAS BEEN CHALLENGING SINCE THERE WAS NOT ENOUGH BREAK BETWEEN LINES OF STORMS TO TAKE OUT OF THE TAFS. THERE MAY BE BREAKS BETWEEN THE STORMS OF LESS THAN 30 MINUTES WITH VFR CONDITIONS BUT WITH COVERAGE OF SHOWERS AND THUNDERSTORMS...PREVAILING CONDITIONS WILL STILL BE MVFR OR LOWER THROUGH 06Z/2AM. WILL CONTINUE TO UPDATE TAFS BASED ON LATEST RADAR TRENDS. MOST OF THE STORMS WILL DIMINISH WITH LOSS OF HEATING BUT SOME SHOWERS MAY LINGER IN THE WEST TONIGHT. AREAS OF LOW CLOUDS...FOG ARE EXPECTED. OUTSIDE OF THUNDERSTORMS...EAST TO SOUTHEAST WINDS WILL PREVAIL. WESTERLY COMPONENT OF WINDS WILL HELP LIFT CEILINGS AFTER 14Z ON MONDAY. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS AGAIN ON MONDAY AFTERNOON WILL BE AT KBLF AND KLWB. EXTENDED AVIATION DISCUSSION... UPPER LOW/TROUGH WILL MOVE INTO WESTERN PA BY MONDAY EVENING. MEANWHILE...A COLD FRONT WILL APPROACH FROM THE OH VALLEY BY TUESDAY NIGHT AND WEDNESDAY. BETWEEN THESE TWO SYSTEM WILL BE A LONGER PERIOD OF VFR WX ON TUESDAY. ONCE THE FRONT STALLS ACROSS OR JUST NORTH OF THE AREA ON WEDNESDAY...PERIODS OF SHOWERS AND THUNDERSTORMS WILL CONTINUE WITH SUB-VFR CONDITIONS THROUGH THE END OF THE WEEK. EXPECT WIDESPREAD LATE NIGHT/EARLY MORNING LOW CLOUDS/FOG WITH IFR-LIFR CIGS/VSBYS. OVERALL...CONDITIONS SHOULD IMPROVE TO MVFR- VFR OUTSIDE SHRA/TSRA ACTIVITY DURING THE AFTERNOONS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FLASH FLOOD WATCH UNTIL 6 AM EDT MONDAY FOR VAZ007-009-010-012- 019-020. NC...NONE. WV...FLASH FLOOD WATCH UNTIL 6 AM EDT MONDAY FOR WVZ042-043-507-508. && $$ SYNOPSIS...KK/MBS NEAR TERM...AMS/KK SHORT TERM...PM LONG TERM...PM AVIATION...AMS/KK

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