Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 251402 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1002 AM EDT MON MAY 25 2015 .SYNOPSIS... HIGH PRESSURE BOTH SURFACE AND ALOFT WILL REMAIN OVER THE EASTERN UNITED STATES TODAY. THIS WILL ENSURE DRY WEATHER FOR THE REMAINDER OF THE HOLIDAY WEEKEND WITH TEMPERATURE AND HUMIDITY TRENDING HIGHER. DEEPER MOISTURE WILL RETURN TO THE AREA BY TUESDAY...WITH SHOWERS AND THUNDERSTORMS DEVELOPING TUESDAY... BECOMING MORE WIDESPREAD ACROSS THE REGION WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 950 AM EDT MONDAY... NO MAJOR CHANGES TO THE OVERALL FORECAST FOR TODAY. IN THE NEAR TERM...HAVE MADE SOME ADJUSTMENTS TO THE SKY COVER GRIDS FOR THE NEXT FEW HOURS ALONG THE CREST OF THE BLUE RIDGE ALONG AND SOUTHWEST OF ROUGHLY ROANOKE. LOW LEVEL MOISTURE WAS BEING CHANNELED WITHIN THIS AREA...AND A REGION OF CUMULUS AND STATRO- CUMULUS THAT HAS BEEN IN THIS AREA SINCE JUST BEFORE DAYBREAK...IS FILLING IN A BIT MORE QUICKLY THAN PREVIOUSLY ADVERTISED. AS THE DAY CONTINUES TO WARM...THIS REGION IS EXPECTED TO MIX OUT AND WE WILL START SEEING HIGHER BASED CLOUD DEVELOPMENT BY THIS AFTERNOON. HAVE ALSO TWEAKED THE LATEST TEMPERATURE...DEW POINT AND WIND SPEED GRIDS TO REFLECT THE LATEST OBSERVATIONS...AND EXPECTED TRENDS INTO THE EARLY AFTERNOON. AS OF 500 AM EDT MONDAY... SOUTHERLY WINDS ON WESTERN PERIPHERY OF DEPARTING ANTICYCLONE WILL GRADUALLY ADVECT LOW LEVEL MOISTURE NORTHWARD INTO THE MOUNTAINS OF NORTH CAROLINA AND FAR SOUTHWEST VIRGINIA TODAY. THIS WILL PERMIT INCREASING CLOUDINESS OVER OUR FAR SOUTHWEST CWA TODAY WITH THE POTENTIAL FOR LATE AFTERNOON AND EVENING SHOWERS WEST OF INTERSTATE 77. THE REMAINDER OF THE CWA WILL CONTINUE TO BASK IN SUNSHINE PER LINGERING SUBSIDENCE. TEMPERATURES THIS AFTERNOON ARE EXPECTED TO REACH INTO THE 80S...WITH THE EXCEPTION OF THE NC MTNS AND HIGHLANDS OF VA/WV WHERE TEMPERATURES WILL TOP OUT IN THE 70S. DEEPER MOISTURE WILL OVERSPREAD THE REMAINDER OF THE REGION TONIGHT INTO TUESDAY...CLOUDS INCREASING. DEWPOINTS WILL BE TRENDING UP...PROMOTING HIGHER HUMIDITY AND HIGHER NIGHT-TIME TEMPERATURES.
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&& .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 400 AM EDT MONDAY... LOOKING AT A VERY SUMMERLIKE WEATHER PATTERN FOR THE MIDDLE OF THE WEEK AS THE UPPER LEVEL RIDGE WHICH MADE FOR ABUNDANT SUNSHINE THIS WEEKEND SHIFTS EAST...LEAVING THE MID ATLANTIC EXPOSED TO A SERIES OF UPPER LEVEL DISTURBANCES APPROACHING FROM THE LOWER MISSISSIPPI VALLEY. SOUTHERLY WINDFLOW IN THE LOW LEVELS WILL ALSO BE FIRMLY ESTABLISHED BY TUESDAY...RETURNING DEEP GULF MOISTURE NORTHWARD ALONG THE APPALACHIAN CHAIN...WHICH WILL PUSH PERCEPTIBLE WATER VALUES IN THE 1.3 TO 1.6 INCH RANGE FOR MUCH OF THE PERIOD. SUCH MOISTURE WILL PROVIDE THE FUEL NECESSARY...WHEN INTERACTING WITH THE UPPER LEVEL DISTURBANCES...TO TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY. ON TUESDAY...WILL KEEP AN EYE ON AN INVERTED TROUGH PASSING JUST WEST OF OUR AREA WHICH WILL SUPPORT SHOWERS AND THUNDERSTORMS...MORE SO FOR THE MOUNTAINS DURING THE AFTERNOON...WITH SOME OF THIS ACTIVITY SPILLING INTO THE PIEDMONT DURING THE EVENING. ON WEDNESDAY...AN UPPER LEVEL TROUGH WILL SHIFT EAST ACROSS THE GREAT LAKES...PUSHING AN ASSOCIATED WEAK COLD FRONT TOWARD THE OHIO RIVER WHERE IT WILL EVENTUALLY STALL. THE INCREASED LOW LEVEL CONVERGENCE AHEAD OF THE FRONT AND GREATER INSTABILITY ALOFT WILL ALLOW FOR MORE WIDESPREAD COVERAGE OF CONVECTION. ANOTHER UPPER LEVEL RIDGE IS EXPECTED TO DEVELOP THURSDAY AS A TROUGH DIGS ACROSS THE INTERMOUNTAIN WEST. INCREASED STABILITY ALOFT COMBINED WITH WINDS BECOMING MORE WESTERLY/DOWNSLOPE WILL KEEP SHOWER AND THUNDERSTORM ACTIVITY A LITTLE LESS DEVELOPED/MORE SPOTTY IN NATURE. DO NOT SEE ANY STRONG SIGNALS FOR ORGANIZED SEVERE THUNDERSTORM ACTIVITY DURING THE PERIOD...HOWEVER CANNOT RULE OUT A FEW STRONG TO SEVERE STORMS DEVELOPING DURING EACH AFTERNOON AND EVENING AREAWIDE. ALSO...WITH A VERY MOIST ATMOSPHERE AND UPPER LEVEL WINDS EXPECTED TO BECOME LIGHT BY THE MIDDLE OF THE WEEK...WILL HAVE TO WATCH FOR AREAS OF HEAVY RAIN DUE TO SLOW MOVING STORMS...WHICH MAY PRODUCE LOCALIZED FLASH FLOODING. STUCK CLOSE TO MAV GUIDANCE FOR TEMPERATURES...WHICH ARE EXPECTED TO RANGE FROM THE UPPER 70S/LOW 80S ACROSS THE MOUNTAINS...TO THE MID 80S FURTHER EAST EACH DAY. OVERNIGHT TEMPERATURES WILL RANGE FROM THE UPPER 50S/LOW 60S WEST...TO THE MID 60S EAST. && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 445 AM EDT MONDAY... A VERY WARM AND MUGGY PERIOD MORE REMINISCENT OF SUMMER LOOKS TO PREVAIL FOR LATE WEEK INTO NEXT WEEKEND AS A MOIST SOUTH/SW FLOW PERSISTS BETWEEN HIGH PRESSURE OFFSHORE AND UPPER TROFFINESS TO THE NW. THIS...PROVIDED STRONG HEATING...SHOULD RESULT IN AT LEAST DIURNAL SHOWERS AND STORMS ESPCLY OVER THE MOUNTAINS WHERE AIDED BY OROGRAPHICS AND DIFFERENTIAL HEATING. UPPER HEIGHTS WILL SLOWLY FLATTEN NEXT WEEKEND AS ANOTHER 5H TROUGH STARTS TO SINK SOUTH FROM THE UPPER MIDWEST WITH ITS ASSOCIATED COLD FRONT LIKELY OOZING TOWARD THE AREA BY SUNDAY. MODELS DIFFER ON HOW FAST THIS BOUNDARY PUSHES SE WITH THE EARLIER EC MORE HUNG UP TO THE NW PER WAVES ALONG THE FRONT...WHILE THE GFS MORE BACKDOOR FASHION AND FASTER. HOWEVER APPEARS THAT THE BOUNDARY WILL BE CLOSE ENOUGH TO PRODUCE MORE WIDESPREAD SHOWERS/STORMS SUNDAY AFTERNOON ESPCLY NORTHERN/WESTERN SECTIONS...WITH MORE SCATTERING SATURDAY OUTSIDE OF THE NW WHERE MORE ORGANIZED PRE-FRONTAL BANDS COULD DROP IN LATE. OTHERWISE OVERALL TREND OF EARLY FOG TO BECOMING PC DURING THE DAY WITH MORE CLOUDS BY SUNDAY...AND DIURNAL CHANCE POPS...EXCEPT SOME LIKELY POPS WEST LATER IN THE WEEKEND. EXPECT TEMPS TO SLOWLY CLIMB EACH DAY WITH HIGHS POSSIBLY TOUCHING 90 OUT EAST OVER THE WEEKEND WITH MAINLY 80S ELSEWHERE. LOWS LOOK QUITE WARM AND MUGGY..ONLY IN THE 60S AT BEST GIVEN MOISTURE AROUND. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... AS OF 230 AM EDT MONDAY... VFR EXPECTED TO CONTINUE THROUGH THE TAF VALID PERIOD...ALTHOUGH SOME SUBTLE SIGNS OF BIGGER CHANGES TO TAKE PLACE THROUGH THE WEEK...WILL BECOME EVIDENT THIS TAF VALID PERIOD. THE UPPER RIDGE CENTERED OVER THE REGION WILL CONTINUE TO DRIFT SLOWLY EAST THROUGH TODAY...MOVING TOWARD THE COAST BY TUESDAY. A BROAD DIFFLUENT UPPER TROUGH ENCOMPASSES MUCH OF THE U.S. WEST OF THE MISSISSIPPI RIVER...AND THIS WILL BE EXPANDING FARTHER EAST THROUGH THE MID PART OF THE WEEK. A SERIES OF UPPER SHORT WAVES WILL TRACK FROM THE MID-SOUTH TO THE NORTHEAST MON-WED...EACH BREAKING DOWN THE UPPER RIDGE AND FORCING IT TO SHIFT FARTHER EAST. LOW-LEVEL MOISTURE WILL BE ON THE INCREASE WITH SOUTHWEST FLOW AROUND A BERMUDA HIGH. THIS WILL RESULT IN INCREASING CU DEVELOPMENT IN THE 040-060 RANGE MON AFTERNOON WITH PERIODS OF BKN CLOUD BASES POSSIBLE DURING THE AFTERNOON...ESPECIALLY WEST OF THE BLUE RIDGE...BUT FEEL THAT THE POTENTIAL FOR SHRA/TSRA WILL REMAIN WEST OF THE CWA TODAY. WINDS TODAY WILL BECOME SSW-SW AFT 13Z MON WITH SPEEDS 7-10KTS AND LOW END GUSTS LIKELY AT BLF/ROA/BCB BY LATE MORNING THROUGH THE AFTERNOON. MEDIUM TO HIGH CONFIDENCE IN CEILINGS THROUGH THE TAF VALID PERIOD. MEDIUM TO HIGH CONFIDENCE IN VISIBILITIES THROUGH THE TAF VALID PERIOD. MEDIUM TO HIGH CONFIDENCE WIND SPEED/DIRECTION THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... SOUTH-SOUTHWEST WINDS WILL CONTINUE TO BRING INCREASING MOISTURE LEVELS INTO THE REGION...ESPECIALLY WEST OF THE BLUE RIDGE TUESDAY. MEANWHILE...THE UPPER-LEVEL WILL BECOME INCREASINGLY FAVORABLE FOR SHOWERS/THUNDERSTORMS AS DISTURBANCES EMANATE FROM A BROAD UPPER TROUGH ACROSS THE CENTRAL/WESTERN U.S. EXPECT SCATTERED SHOWERS/THUNDERSTORMS MAINLY THROUGH THE I-77 CORRIDOR TUESDAY AFTERNOON...SPREADING FARTHER EAST ACROSS MUCH OF THE CWA WEDNESDAY THROUGH THE END OF THE WEEK. WED-THU AT THIS POINT APPEAR TO BE THE MOST ACTIVE DAYS FOR THUNDERSTORMS...WITH SOME STRONG THUNDERSTORMS AND HEAVY RAIN POSSIBLE DURING THIS TIME FRAME. THE THREAT FOR SHOWERS/THUNDERSTORMS MAY WELL LINGER FOR SEVERAL SUBSEQUENT DAYS AS A WEAK FRONTAL BOUNDARY/BAROCLINIC ZONE STALL ACROSS THE REGION WITH ADDITIONAL UPSTREAM ENERGY REMAINING IN PLACE. ASIDE FROM SHOWERS/THUNDERSTORMS...CONDITIONS SHOULD GENERALLY BE VFR OR MVFR AT WORST...BUT INCREASING LIKELIHOOD OF EARLY MORNING IFR-LIFR CONDITIONS IN BR/FG AND LOW CLOUDS AS MOISTURE LEVELS INCREASE AND LATE DAY SHOWERS LEAVE WET GROUND IN PLACE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/PM NEAR TERM...DS/PM SHORT TERM...NF LONG TERM...JH/NF AVIATION...PM

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