Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 051955 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 355 PM EDT SUN JUL 5 2015 .SYNOPSIS... AN UPPER LOW OVER EAST TENNESSEE 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 354 PM EDT SUNDAY... FLASH FLOOD WATCH REMAINS IN EFFECT FOR FAR WEST THROUGH TONIGHT. THERE REMAINS THE POTENTIAL FOR HEAVY RAINS WITH CONVECTION THIS AFTERNOON 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 SATURATE GROUNDS WILL BE OF HIGH CONCERN. A WEST TO EAST ORIENTATION NORTH OF FRONTAL BOUNDARY COULD ALSO RESULT IN LOCAL WATER PROBLEMS DEPENDING ON LOCATION. 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 EASTERN TENNESSEE WILL LIFT NORTHEAST THIS AFTERNOON INTO TONIGHT AND REACH WESTERN PENNSYLVANIA BY MONDAY EVENING. SURFACE FRONTAL BOUNDARY REMAINS WEST TO EAST ACROSS SOUTHERN PORTIONS OF FORECAST AREA THIS AFTERNOON AND WILL LIFT NORTH AS WARM FRONT TONIGHT INTO MONDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE IN THE UNSTABLE MOIST AIR THIS AFTERNOON INTO TONIGHT. LOW LEVEL MOISTURE POOLING IS OCCURRING ALONG THE SURFACE BOUNDARY NEAR THE VA/NC BORDER. 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 ATTMS. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... AS OF 120 PM EDT SUNDAY... POOR AVIATION CONDITIONS EXPECTED THROUGH THE TAF VALID PERIOD. A CLOSED UPPER LOW OVER EASTERN TENNESSEE THIS AFTERNOON WILL DRIFT SLOWLY NORTHEAST TONIGHT AND REACH WESTERN PENNSYLVANIA BY LATE MONDAY. MVFR CONDITIONS WILL PREVAIL WITH POCKETS OF IFR/LIFR IN CONVECTION AND LOW CLOUDS. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON INTO TONIGHT...WITH THE BEST COVERAGE AND DURATION ACROSS THE WESTERN SITES...ESPECIALLY KLWB AND KBLF. LOCATIONS WITH A GOOD CHANCE FOR THUNDERSTORMS ARE WHERE SOLAR HEATING WILL COMBINE WITH ENOUGH INSTABILITY TO SUPPORT THUNDERSTORMS. DAN IS THE TAF SITE WITH BEST CHANCE FOR A THUNDERSTORM THIS AFTERNOON INTO THIS EVENING. MOST OF THE STORMS WILL DIMINISH WITH LOSS OF HEATING BUT SOME SHOWERS MAY LINGER IN THE WEST TONIGHT. AREAS OF LOW CLOUDS...FOG...AND DRIZZLE WILL LIKELY PERSIST OVERNIGHT AFTER THE HEAVIER RAIN DRIFTS NORTH OF THE AREA. UNSETTLED WEATHER WILL CONTINUE MONDAY WITH MVFR/IFR SHOWERS AND EMBEDDED THUNDERSTORMS. THE BEST CHANCE FOR CONVECTION WILL OCCUR ACROSS THE NORTH. OUTSIDE OF THUNDERSTORMS...EAST TO SOUTHEAST WINDS WILL PREVAIL AT 4-7KTS TONIGHT. THEN WINDS BECOMING LIGHT AND VARIABLE OVERNIGHT INTO MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWEST AT 5-10 KTS MONDAY AFTERNOON. MEDIUM CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS DURING THE TAF PERIOD. EXTENDED AVIATION DISCUSSION... POOR AVIATION CONDITIONS TO CONTINUE INTO NEXT WEEK...BUT WINDOWS OF OPPORTUNITY FOR VFR CONDITIONS INCREASE TUE. UPPER LOW/TROUGH WILL MOVE INTO WESTERN PA BY MONDAY EVENING. MEANWHILE...A COLD FRONT WILL APPROACH FROM THE OH VALLEY BY WED. THIS LEAVES A VERY UNSETTLED/WET PATTERN ACROSS THE REGION THROUGH MOST OF THE PERIOD. TUE THROUGH THE DAY OFFERS THE BEST CHANCE FOR SEVERAL HOURS OF VFR...ESPECIALLY EAST OF THE BLUE RIDGE. 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 THROUGH LATE TONIGHT FOR VAZ007-009-010-012- 019-020. NC...NONE. WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ042-043-507-508. && $$ SYNOPSIS...KK/MBS NEAR TERM...KK SHORT TERM...PM LONG TERM...PM AVIATION...KK/RAB

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