Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 271307 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 907 AM EDT MON OCT 27 2014 .SYNOPSIS... HIGH PRESSURE IS CENTERED OVERHEAD THIS MORNING. THIS FEATURE WILL DRIFT EAST TO ALONG THE COAST BY THIS EVENING AND WILL INFLUENCE OUR WEATHER THROUGH TUESDAY. MEANWHILE A COLD FRONT WILL MOVE EAST ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST TODAY...CROSS THE GREAT LAKES AND OHIO VALLEY TUESDAY...THEN ACROSS THE MID ATLANTIC WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 907 AM EDT MONDAY... HIGH PRESSURE OVERHEAD THIS MORNING WILL SLIDE EAST THIS AFTERNOON INTO TONIGHT. THIS MORNING 8AM/12Z SOUNDING SHOWED AN IMPRESSIVE INVERSION WITH 57 DEGREES JUST UP AT 3500 FEET WITH A DRY WEST TO NORTHWEST FLOW. WITH A DRY AIRMASS IN PLACE...THIS AFTERNOON WILL FEATURE PLENTY OF SUNSHINE. MADE SOME MINOR ADJUSTMENTS IN ISC TEMPERATURES FOR THIS MORNING INTO THIS AFTERNOON. ENJOY THE NICE AFTERNOON. AS OF 730 AM EDT MONDAY... 1020 MB HIGH PRESSURE WAS CENTERED OVERHEAD THIS MORNING. THE AIRMASS ASSOCIATED WITH THIS ANTICYCLONE WAS VERY DRY...PWAT IN LAST EVENINGS SOUNDING A LIP CRACKING 0.18. THIS MAKES FOR A SIMPLE FORECAST IN THE NEAR TERM WITH NO THREAT OF RAIN. ASIDE FOR A FEW WHISPS OF CIRRUS...SKIES SHOULD BE SUNNY TODAY...AND WITH HIGH PRESSURE CENTERED OVERHEAD WINDS WILL BE LIGHT AND VARIABLE. LACK OF MOISTURE IN THE AIR WILL ALLOW FOR TODAYS SOLAR INSOLATION TO GO INTO SENSIBLE HEATING...THUS FAVORING THE WARMER MOS GUIDANCE. TONIGHTS T-MINS WILL BE SIMILAR TO LAST NIGHT WITH VALLEYS DECOUPLING AND BECOMING COOLER THAN THE RIDGES...THE VALLEY BOTTOMS DIPPING INTO THE U30S/L40S VS LOWER 50S ALONG THE RIDGE TOPS.
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&& .SHORT TERM /TUESDAY THROUGH THURSDAY/... AS OF 400 AM EDT MONDAY... MEDIUM RANGE MODELS ARE IN RELATIVELY GOOD AGREEMENT THAT AN UPPER LEVEL SYSTEM TRACKS THROUGH THE GREAT LAKES INTO NEW ENGLAND WEDNESDAY INTO WEDNESDAY NIGHT...AND PUSHING A COLD FRONT THROUGH OUR AREA WEDNESDAY. THE GFS IS WEAKER AND LESS AMPLIFIED WITH THIS SYSTEM COMPARED TO THE NAM AND 00Z ECMWF...AND LEANED TOWARD THE MORE AMPLIFIED/SLOWER ECMWF/NAM. REGARDLESS...THERE IS GOOD CONSENSUS THAT A DEEP SOUTHWEST FLOW WILL PREVAIL TUESDAY WITH 850MB TEMPS FORECAST TO BE 1-2+ STANDARD DEVIATIONS ABV NORMAL. BOTH THE MAV AND MET GUIDANCE HAVE BEEN TRENDING WARMER WITH HIGHS TUESDAY. THIS WAS REFLECTED IN THE FORECAST WITH HIGHS BEING PUSHED UP A DEGREE OR SO WHICH WILL BE NEAR RECORD LEVELS AT LWB/BLF/BCB (SEE CLIMATE SECTION BELOW FOR RECORDS ON TUESDAY). THE ONLY POTENTIALLY INHIBITING FACTOR WOULD BE A VEIL OF HIGH CLOUDS INCREASING. A NARROW RIBBON OF MOISTURE WITH PWAT VALUES EXCEEDING 1" ZIPS THROUGH THE FORECAST AREA WITH THE FRONT TUESDAY NIGHT INTO WEDNESDAY. CONTINUED TO KEEP THUNDER OUT OF THE FORECAST WITH BEST DYNAMICS LIFTING NORTH AND VERY SMALL/IF ANY CAPES EXPECTED. LEANED TOWARD THE WARMER SIDE OF GUIDANCE FOR LOWS TUESDAY NIGHT...ESPECIALLY IN THE HIGHER ELEVATIONS WITH A 25-30KT 850MB SOUTHWEST FLOW IN PLACE. CLOUDS AND SHOWERS WEDNESDAY ALONG WITH COOLING 1000-850MB THICKNESSES BEHIND THE FRONT SHOULD BRING TEMPS DOWN INTO THE 60S IN THE MOUNTAINS ON WEDNESDAY. WITH THE 00Z ECMWF COMING IN SLOWER WITH THIS SYSTEM...AND DEVELOPING A WEAK WAVE OF SFC LOW PRESSURE ALONG THE FRONT BY 00Z THURSDAY...KEPT A CHANCE FOR SHOWERS IN THE FAR SOUTHEAST EARLY WEDNESDAY NIGHT. OTHERWISE...HIGH PRESSURE BUILDING INTO THE OHIO AND TENNESSEE VALLEYS LATE WEDNESDAY NIGHT MAY ALLOW WINDS TO DIMINISH AND CLOUDS TO CLEAR ENOUGH IN THE WEST FOR VALLEYS TO DROP INTO THE 30S FOR LOWS. WINDS WILL CONTINUE TO DIMINISH THURSDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST AND TEMPS A FEW DEGREES BELOW NORMAL WITH HIGHS IN THE 50S IN THE MOUNTAINS TO THE LOWER 60S IN THE EAST. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... AS OF 100 PM EDT SUNDAY... OVERALL DRY BUT MUCH COOLER PERIOD IN STORE ESPCLY BY NEXT WEEKEND AS A STRONG 5H TROUGH DIGS SOUTH INTO THE REGION LATE IN THE WEEK FOLLOWED BY CHILLY HIGH PRESSURE BUILDING IN FROM THE NW DURING THE WEEKEND. THIS WILL PERHAPS SET THE STAGE FOR SOME OF THE COLDEST AIR OF THE SEASON NEXT WEEKEND WITH WIDESPREAD FROST OR FREEZING CONDITIONS BY SUNDAY MORNING EVEN OUT ACROSS THE EAST WHERE THE GROWING SEASON CONTINUES. OTRW INITIAL WEAK SURFACE FRONT EXITING BY EARLY THURSDAY...WILL ALLOW A GLANCING SHOT OF COOL ADVECTION TO KNOCK TEMPS BACK TO MORE SEASONAL LEVELS WITH ANY EARLY MORNING CLOUDS/SHOWERS SE EXITING FOR INCREASING SUNSHINE UNDER WEAK HIGH PRESSURE DURING THE DAY. HIGH PASSES OVERHEAD AND WEAKENS THURSDAY NIGHT INTO FRIDAY AS A SECONDARY COLD FRONT APPROACHES FROM THE NW AND PASSES THROUGH BY LATE FRIDAY. THIS BOUNDARY ASSOCIATED WITH THE DIGGING UPPER TROUGH AND PASSING SHORTWAVE ENERGY TO THE NORTH THAT WILL CUTOFF OVER NEW ENGLAND AND DRIVE THE STRONGER 85H COLD ADVECTION TO THE SE. MODEL CONSENSUS AGAIN MAINTAINS THAT THIS FEATURE WILL BE WELL TO THE NE WHERE PHASING OF SURFACE LOW PRESSURE MAY TAKE PLACE. THIS SHOULD KEEP A STRONG AND MUCH COLDER NW FLOW OF AIR OVER THE REGION FRIDAY NIGHT INTO SATURDAY NIGHT WITH ONLY SOME UPSLOPE RAIN/SNOW SHOWERS LIKELY AT THIS POINT FAR WEST. LARGE SURFACE RIDGE TO THE NW FINALLY BUILDS IN BY SUNDAY RESULTING IN DIMINISHING WINDS BUT STILL CHILLY TEMPS DESPITE SUNSHINE. HOWEVER GUIDANCE NOT QUITE AS COLD AS YESTERDAY GIVEN SLIGHTLY LESS DIGGING ALOFT BUT APPEARS ENOUGH TO GO FROM 50S/LOW 60S FRIDAY...COOLING TO 40S WEST/50S EAST SATURDAY AND MOSTLY 50S SUNDAY AS COLD AIR ALOFT STARTS TO DEPART. LOWS MOSTLY 30S FRIDAY NIGHT AND OVERALL BELOW FREEZING WITH 20S TO LOWER 30S BY EARLY SUNDAY. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... AS OF 800 AM EDT MONDAY... DRY HIGH PRESSURE WILL MOVE OVERHEAD THIS MORNING AND THEN DRIFT EAST TO THE ATLANTIC COAST BY SUNSET. RESULT WILL BE WIDESPREAD VFR CONDITIONS...WINDS LIGHT AND VARIABLE. EXTENDED AVIATION DISCUSSION... VFR CONDITIONS EXPECTED AGAIN TUESDAY. LOWER RESTRICTIONS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY BUT FAIRLY BRIEF WITH THE PASSING OF THE NEXT FRONT. VFR TO RETURN TO ALL SITES THURSDAY. NEXT CHANCE FOR ANY SORT OF RESTRICTIONS WOULD BE ONLY AT BLF AND LWB FRIDAY NIGHT OR SATURDAY ASSOCIATED WITH AN UPPER LEVEL TROUGH AND DRY SURFACE FRONT WHICH WILL BRING A PERIOD OF LOW LEVEL STRATO-CUMULUS TO THE WEST VIRGINIA HIGHLANDS. THE PASSAGE OF THIS FRONT WILL ALSO BRING COLDER CONDITIONS TO THE ENTIRE REGION WITH BLUSTERY NORTHWEST WINDS FOR THE WEEKEND. && .FIRE WEATHER... POOR HUMIDITY RECOVERY LAST NIGHT RESULTED IN LITTLE OR NO DEW FORMATION. AS A RESULT...LEAF LITTER WILL BE DRY FROM THE START THIS MORNING. HUMIDITY MINIMUMS THIS AFTERNOON MAY TEST 20 PERCENT. DRY HIGH PRESSURE WILL BE CENTERED OVERHEAD TODAY PROMOTING FULL SUNSHINE...UNSEASONABLY WARM TEMPERATURES...AND LOW HUMIDITY. UNLIKE YESTERDAY...THE WIND WILL BE LIGHT AND VARIABLE. THE INCREASED SUBSIDENCE WILL ALSO RESULT IN LOW MIXING HEIGHTS. SOMEWHAT BETTER HUMIDITY RECOVERY IS EXPECTED TONIGHT...ESPECIALLY IN THE VALLEYS...BUT REMAIN POOR ALONG THE RIDGE TOPS. WINDS WILL BEGIN TO INCREASE TUESDAY AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT WILL PROVIDE A PERIOD OF CLOUD COVER WEDNESDAY ALONG WITH THE THREAT OF SHOWERS...RAINFALL AMOUNTS OF A TENTH /0.10/ TO A QUARTER /0.25/ OF AN INCH. && .CLIMATE... RECORD HIGH TEMPS FOR 10/28... ROANOKE.....86 (1919) LYNCHBURG...88 (1919) DANVILLE....85 (1984) BLUEFIELD...77 (1984) LEWISBURG...76 (1984) BLACKSUBRG..80 (1984) && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...KK/PM SHORT TERM...PH LONG TERM...JH AVIATION...PM FIRE WEATHER...PM CLIMATE...JH

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