Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 301828 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 228 PM EDT TUE JUN 30 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH THE REGION THROUGH WEDNESDAY. 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 223 PM EDT TUESDAY... FORECAST UPDATED TO ADD SEVERE THUNDERSTORM WATCH 377 FOR THE ENTIRE FORECAST AREA UNTIL 9 PM. SVR THREAT INCREASES AS MLCAPES INCREASE OVER 1500 J/KG. NOT GOING TO SEE SVR EVERYWHERE BUT THE THREAT OF ISOLATED DAMAGING WINDS AND LARGE HAIL EXISTS THROUGH EARLY EVENING. PREVIOUS DISCUSSION... UPDATED FORECAST TO REFLECT LOWER THREAT OF SHRA/TSRA EARLY ON BUT THE HIGH-RES MODELS ARE STILL FIRING UP CONVECTION THIS AFTERNOON EAST OF THE BLUE RIDGE...WITH ANOTHER BATCH RIDING IN FROM ERN KY TOWARD MID AFTERNOON. MESOANALYSIS SHOWED HIGHER THETA-E AND DEWPOINTS APPROACHING THE PIEDMONT...WITH SECONDARY RIDGE OVER MID TN/WESTERN KY. OUR FORECAST AREA SEEMS TO BE IN A LULL. HOWEVER...CLEARING SKIES OVER THE WEST AND SUNNY CONDITIONS IN THE SOUTHEAST WILL HAVE A POSITIVE AFFECT ON CAPES THIS AFTERNOON. THERE ARE SUBTLE UPPER AIR DISTURBANCES IN PLACE FROM INDIANA TO TN AND OVER SOUTHSIDE VA AS OF 16Z. THESE SHOULD HELP DEVELOP STORMS THIS AFTERNOON. FORECAST HIGHS ON TRACK TO REACH UPPER 80S OUT EAST TO UPPER 70S/LOWER 80S WEST. PREVIOUS VALID DISCUSSION... SHOWERS 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 THIS EVENING AND IN THE FAR NORTHWEST COUNTY WARNING AREA TONIGHT. 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 /19Z TUESDAY THROUGH SUNDAY/... AS OF 120 PM EDT TUESDAY... UNDER INCREASING INSTABILITY AND SOME WEAK UPPER LEVEL SUPPORT...LOOK FOR CU THIS AFTERNOON TO TOWER INTO CBS AS WE HEAD THROUGH 21Z. HIGH-RES MODELS SHOWING ENOUGH CONSENSUS ON WHERE CONVECTION WILL FIRE AND MOVE IN. SO...WILL KEEP VCTS IN OVER MOST TAF SITES IN THE 19-21Z TIME FRAME. CONFIDENCE IS HIGH ENOUGH THAT SHOULD SEE STORMS IN THE BLF AREA BETWEEN 20-23Z...SO ADDED A TEMPO GROUP HERE. CONFIDENCE NOT AS HIGH NORTHEAST. MODELS SEEM TO PINPOINT SOUTHSIDE VA NEAR DAN EARLY...THEN MOVE THE EMPHASIS WEST OF THE BLUE RIDGE AFTER 20Z. ANY SHOWERS OR TSRA WILL BRING GUSTY WINDS WITH POTENTIAL FOR SOME SVR GUSTS PER LATEST STORM PREDICTION CENTER OUTLOOK. AVIATION INTERESTS WILL NEED TO MONITOR RADAR AND SIGMETS THROUGH THIS EVENING. AS WE HEAD INTO THE OVERNIGHT THE ACTIVITY WINDS DOWN. WE WILL SEE SOME FOG AND LOWER CIGS WORK INTO THE MTNS AFTER 06Z...SO KEPT THE PREVIOUS FORECAST AND TRIED TO TOUCH ON MORE FOG AT LWB/DAN/BCB. AS WE HEAD THROUGH WED MORNING WE SCATTER OUT WITH VFR EXPECTED. TSRA WILL BE MORE WIDELY SCATTERED WEDNESDAY WITH FOCUS SHIFTING SOUTHWEST. BEST THREAT FOR STORMS WILL LIE FROM BLF-BCB AND SOUTHWEST INTO TN. 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/WP SHORT TERM...KK LONG TERM...WP AVIATION...AMS/JH/WP

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