Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 290347 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1147 PM EDT MON JUL 28 2014 .SYNOPSIS... AN UPPER TROUGH OF LOW PRESSURE WILL REMAIN CENTERED OVER THE EAST COAST THROUGH THE MIDDLE OF THE WEEK. LIKEWISE...COOL HIGH PRESSURE WILL SETTLE OVER THE REGION THROUGH WEDNESDAY. DURING THE LATTER HALF OF THE WEEK AND HEADING INTO THE WEEKEND...THE UPPER TROUGH WILL RETROGRADE WESTWARD...AND ALLOW FOR AN INCREASE IN MOISTURE...MODERATING TEMPERATURES...AND POTENTIAL FOR SHOWERS AND STORMS. && .NEAR TERM /THROUGH TUESDAY/... AS OF 1140 PM EDT MONDAY... FEW SHOWERS OVER SE WV SHOULD BE WANING OVERNIGHT WITH LOSS OF HEATING. WINDS HAVE CALMED IN THE VALLEYS...SO PATCHY FOG MAY FORM IN TYPICAL LOCATIONS AROUND RIVERS/LAKES BY DAWN WITH COOLER AIR RUSHING IN. SKIES WILL BE STAYING SOMEWHAT CLOUD IN THE UPSLOPE OF SE WV OVERNIGHT BUT SCATTERED OUT TO THE EAST. FORECAST LOWS APPEAR ON TRACK...FROM THE LOWER 50S ACROSS THE MTNS TO AROUND 60 OUT EAST. PREVIOUS VALID DISCUSSION... ON TUESDAY...OUR COOL PATTERN WILL CONTINUE WITH THE AXIS OF THE UPPER TROUGH STILL OVER OUR REGION...AND THE CENTER OF SURFACE HIGH PRESSURE WILL APPROACH FROM THE WEST. EMBEDDED WITH THE MAIN UPPER TROUGH PATTERN...MODEL GUIDANCE OFFER A SOLUTION WITH A WEAK DISTURBANCE WITHIN THE MAIN FLOW CROSSING MAINLY THE SOUTHERN HALF OF THE AREA ON TUESDAY. WILL CONTINUE TO ALLOW FOR ISOLATED SHOWERS IN THE FORECAST ACROSS THE SOUTHWESTERN PART OF THE AREA...IN THE PATH OF THE DISTURBANCE AND WITHIN A ZONE OF WEAK UPSLOPE 850 MB FLOW. HIGH ON TUESDAY ARE EXPECTED TO AVERAGE AROUND FIVE DEGREES COOLER THAN THOSE REALIZED TODAY. LOW TO MID 70S ARE FORECAST ACROSS THE MOUNTAINS WITH UPPER 70S TO NEAR 80 ACROSS THE PIEDMONT. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... AS OF 345 PM EDT MONDAY... BY WEDNESDAY MORNING SURFACE HIGH PRESSURE IS CENTERED OVER THE FORECAST AREA. A VERY WEAK PRESSURE GRADIENT REMAINS IN PLACE THROUGH THURSDAY. PRECIPITABLE WATER VALUES GRADUALLY INCREASE BACK UP INTO THE 1.0 TO 1.5 INCH RANGE BY LATE THURSDAY. BUFKIT FORECAST SOUNDINGS FOR WEDNESDAY SHOW ENOUGH MIXING TO BRING DEW POINTS DOWN INTO THE 40S FOR MUCH OF THE AREA DURING THE AFTERNOON. WILL STAY CLOSE TO COOLER GUIDANCE FOR LOWS ON BOTH TUESDAY NIGHT AND WEDNESDAY NIGHT. RECORD LOWS ARE STILL POSSIBLE TUESDAY NIGHT WITH LOWS 5 TO 15 DEGREES BELOW NORMAL. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 345 PM EDT MONDAY... UPPER 500 MB TROF OVER THE NORTHEAST UNITED STATES AMPLIFIES ON FRIDAY AND SATURDAY WITH A SIGNIFICANT SHORT WAVE OVER THE OHIO VALLEY. MODELS SIMILAR IN SHOWING HEIGHT FALLS ON THE SOUTHERN END OF THE TROF AND WHAT MAY EVENTUALLY BE A CUT OFF LOW OVER THE LOWER MISSISSIPPI VALLEY OR SOUTHEAST UNITED STATES MONDAY. MOISTURE BEGINS TO INCREASE ACROSS THE AREA ON FRIDAY BUT LITTLE IN THE WAY OF ANY ORGANIZED LIFT TO TRIGGER ANY PRECIPITATION ASIDE FROM DAILY THREAT OF AIRMASS TYPE SHOWERS AND THUNDERSTORMS. WITH LITTLE CHANGE IN THE AIR MASS THERE WILL BE MINIMAL CHANGES IN HIGH AND LOW TEMPERATURES EACH DAY. TEMPERATURES WILL BE NEAR NORMAL. NOT ANTICIPATING ANY EXTREMES. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... AS OF 730 PM EDT MONDAY... INCLINED TO KEEP THE NW FLOW SC IN THE WEST THROUGH MOST OF THE EVENING...WITH MODELS SHOWING DOWNWARD TREND IN CIGS AT LWB/BLF AND POSSIBLY BCB OVERNIGHT WITH MVFR/IFR CIGS. IN ADDITION FOG WILL BE AN ISSUE...IF ANY CLEARING TAKES PLACE DESPITE THE DRY AIRMASS...DUE TO WARM WATERS/COOLER AIR...AT LWB/BCB AND PERHAPS BLF. BLF WILL BE MORE DUE TO LOWER CLOUDS IN THE MTNS THAN RADIATION FOG AS WINDS STAY UP THERE. FURTHER EAST VFR EXPECTED. ANY SUB-VFR CONDITIONS WILL RAPIDLY IMPROVE TO VFR TUESDAY MORNING. EXTENDED AVIATION DISCUSSION... PERSISTENT TROUGH PATTERN IN THE EAST WILL GRADUALLY RETROGRADE WEST BY THE END OF THE WEEK. MAINLY VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST THURSDAY SAVE FOR SOME LATE NIGHT/EARLY MORNING PATCHY MVFR FOG IN THE MOUNTAIN AND RIVER VALLEYS. AFTER THURSDAY...WITH THE TROUGH AXIS FARTHER WEST...THIS WILL ALLOW FOR A RETURN OF ATLANTIC MOISTURE AND A GREATER ABUNDANCE OF SHOWERS...AND POTENTIALLY STORMS...IN THE FORECAST HEADING INTO THE WEEKEND. THIS ALSO WILL ALLOW FOR INCREASED CHANCES OF SUB-VFR CONDITIONS WITHIN THE AREA OF THE SHOWERS...AND THEN AGAIN OVERNIGHT IN THE FORM OF LIGHT FOG OR STRATUS AS BOUNDARY MOISTURE GETS TRAPPED UNDER THE NOCTURNAL INVERSION. && .CLIMATE... JULY 29TH RECORD LOWS: ROANOKE......52...1925 BLUEFIELD....55...2013 DANVILLE.....58...1968 LEWISBURG....46...2013 LYNCHBURG....53...1920 BLACKSBURG...50...1983 JULY 30TH RECORD LOWS: ROANOKE......54...1997 BLUEFIELD....50...1981 DANVILLE.....60...1972/81/83/2013 LEWISBURG....46...2013 LYNCHBURG....52...1997 BLACKSBURG...50...1973/81 JULY 31ST RECORD LOWS: ROANOKE......49...1914 BLUEFIELD....49...1997 DANVILLE.....55...1966 LEWISBURG....48...1997 LYNCHBURG....49...1997 BLACKSBURG...44...1997 && .EQUIPMENT... THE NOAA WEATHER RADIO AT WYTHEVILLE VA...WZ2500...BROADCASTING ON A FREQUENCY OF 162.450 MHZ...IS OFF THE AIR...DUE TO PHONE LINE ISSUES. PHONE COMPANY IS WORKING ON IT. NO ESTIMATED TIME FOR RETURN TO SERVICE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS/WP SHORT TERM...AMS LONG TERM...AMS AVIATION...DS/WP CLIMATE...DS/PH EQUIPMENT...DS

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