Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 220245 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1045 PM EDT SUN SEP 21 2014 .SYNOPSIS... A COLD FRONT WILL MOVE EAST TONIGHT...AND WILL REACH THE EAST COAST BY MONDAY MORNING. MONDAY THROUGH THURSDAY...A LARGE HIGH PRESSURE SYSTEM WILL COVER MUCH OF THE EASTERN UNITED STATES. && .NEAR TERM /THROUGH MONDAY/...
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AS OF 1045 PM EDT SUNDAY... AN UPPER TROUGH WILL AMPLIFY ACROSS THE EAST TONIGHT INTO MONDAY. THE ASSOCIATED COLD FRONT WILL SWEEP EAST ACROSS THE FORECAST AREA OVERNIGHT. WITH THE PASSAGE OF THE FRONT...WINDS WILL INCREASEFROM THE NORTHWEST...DEWPOINTS TAKING A NOTICEABLE PLUNGE...READINGS FALLING INTO THE 40S. THIS AIRMASS CHANGE WILL RESULT IN A NOTICEABLY COOLER FEELING TO THE AIR STARTING MONDAY. FRONTAL PASSAGE WILL BRING A GENERAL CLEARING TO AREAS EAST OF THE MOUNTAINS. UPSLOPE NORTHWESTERLY FLOW WILL RESULT IN LINGERING CLOUDINESS ALONG THE WESTERN SLOPES. AN UPPER LEVEL TROUGH WILL PIVOT ACROSS THE REGION WITH NORTHWEST FLOW AND LOW LEVEL MOISTURE HOLDING CLOUDS BANKED UP AGAINST WESTERN SLOPES THROUGH MONDAY MORNING. ONCE THIS TROUGH AXIS TRACKS TO THE MID ATLANTIC COAST MONDAY AFTERNOON...DRY AIR WILL ERODE MOUNTAIN CLOUDS RETURNING SUNSHINE. DOWNSLOPE NORTHWEST FLOW ANTICIPATED EAST OF THE BLUE RIDGE TO KEEP MOSTLY CLEAR SKIES MONDAY. PLAYED HIGH TEMPERATURES MONDAY CLOSE TO ADJMAV WITH READINGS FROM THE MID 60S IN THE MOUNTAINS TO THE UPPER 70S IN THE PIEDMONT. 850 MB WINDS OF 25 TO 30 KTS WILL RESULT IN BREEZY CONDITIONS EARLY MONDAY...ESP ALONG THE RIDGE CRESTS WHERE SURFACE GUSTS OF 25 MPH ARE POSSIBLE.
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&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 240 PM EDT SUNDAY... LOOKING AT A DRY AND COOL AIRMASS MON NIGHT-WED...WITH SFC HIGH SHIFTING FROM THE OHIO VALLEY TO OFF THE NORTHEAST COAST. THIS WILL SET UP A CLASSIC WEDGE OVER OUR AREA...WHICH AT FIRST WILL BE CLEAR/SUNNY AND DRY/COOL. WED-WED NIGHT...THE ECMWF HAS BEEN TRENDING TOWARD A CLOUDIER...WETTER SOLUTION THAN THE OTHER OPERATIONAL MODELS...AND ATTM LEANING TOWARD A BLEND. THINK POTENTIAL EXISTS FOR ENOUGH SOUTHEAST FLOW ALOFT AND NE-E FLOW AT THE SFC TO DRAW IN THE SOME ATLANTIC MOISTURE. FOR NOW WILL LIMIT SLIGHT CHANCE OF RAIN IN THE EASTERN TWO THIRDS OF THE FORECAST AREA LATE WED NIGHT...WITH INCREASING CLOUDS. FOR TEMPS EXPECT THE COOLER MORNING TO BE TUESDAY MORNING...WHERE SOME VALLEYS IN SE WV/FAR SW VA MAY DROP INTO THE MID TO UPPER 30S WHILE MOST WILL SEE 40S. TEMPS REBOUND INTO THE MID TO UPPER 60S FOR HIGHS TUESDAY IN THE MOUNTAINS...TO LOWER TO MID 70S EAST. TEMPS MODIFY SOME WED NIGHT WITH 40S MOST PLACES...COOLER IN THE MOUNTAIN VALLEYS...THEN WARM AGAIN INTO THE MID 60S TO LOWER 70S...WITH WARMEST TEMPS ACROSS THE FAR SW CWA WHILE SE FLOW OUTSIDE THE WEDGE MAY ENHANCE TEMPS. WED NIGHT MODIFIES SOME WITH INCREASING CLOUDS WHERE LOWS RANGE FROM THE UPPER 40S TO LOWER 50S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 100 PM EDT SUNDAY... A STRONG SURFACE HIGH OVER THE NE STATES ON THURSDAY WILL SLOWLY DRIFT WESTWARD TO THE GREAT LAKES BY THE WEEKEND. THIS WILL LEAD TO A PROLONGED EASTERLY FLOW ACROSS THE REGION. HIGH TEMPERATURES WILL BE 5-10 DEGREES BELOW NORMAL RANGING FROM THE MID TO UPPER 60S ACROSS THE MOUNTAINS TO LOWER 70S EAST OF THE BLUE RIDGE. MODELS ARE STARTING TO AGREE ON A WEAK UPPER LEVEL DISTURBANCE FORMING ACROSS THE SE STATES LATE IN THE WEEK...HOWEVER THERE IS STILL MAJOR DIFFERENCES ON PLACEMENT WHICH WILL AFFECT HOW MUCH MOISTURE CAN GET PULLED UP INTO THE REGION. THE GFS CONTINUES TO BE MUCH DRIER THAN THE ECMWF. DUE TO THE MODEL DIFFERENCES...ONLY SLIGHT CHANCE POPS IN FROM THE BLUE RIDGE EASTWARD. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... AS OF 740 PM EDT SUNDAY... COLD FRONT NEAR AN MGW-BKW LINE AT THIS HOUR. PRE-FRONTAL ACTIVITY DISSIPATED FOR THE MOST PART AS IT CROSSED THE ALLEGHANY FRONT...WITH FINAL LINE OF FRONTAL -SHRA AND PERHAPS ISOLD TSRA NEAR THE FRONT AT THIS HOUR. MODELS SHOW THIS ACTIVITY WILL MAKE IT TO THE ALLEGHANY FRONT...THEN DISSIPATE BEFORE MOVING EAST OF THE BLUE RIDGE. LWB AND ESPECIALLY BLF COULD STILL SEE A BRIEF SHRA WITH BRIEF IFR VSBY/CIG...BUT THAT SHOULD BE ABOUT IT FOR THAT. HAVE REMOVED MENTION OF SHRA FROM ROA/LYH/DAN AS LITTLE SUPPORT FOR ACTIVITY TO REACH THOSE AREAS. RETAINED VCSH FOR BCB FOR A COUPLE MORE HOURS. BEHIND THE FRONT OVERNIGHT...EXPECT TYPICAL WINTERLIKE SETUP WITH CLEARING EAST OF THE BLUE RIDGE AND DEVELOPING MOSTLY MVFR STRATUS DECK TO THE WEST. BCB WILL BE ON THE EDGE OF VFR TO MVFR OVERNIGHT. LWB...AND ESPECIALLY BLF WILL SEE MVFR CIGS HANG IN MUCH OF THE DAY MON WITH UPSLOPE WEST FLOW. VFR CONDITIONS WILL PREVAIL TO THE EAST. BCB SHOULD SEE CIGS IMPROVE TO VFR IN THE 16Z-18Z TIME FRAME. EAST OF THE BLUE RIDGE...VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF VALID PERIOD. CANNOT SUPPORT IFR-LIFR FG ADVERTISED BY GFS/NAM MOS TAFS WITH POTENTIAL STRATUS DECK TO THE WEST OF THE ALLEGHANY FRONT AND DOWNSLOPE WINDS TO THE EAST. WINDS WSW 6-8KTS IN ADVANCE OF THE FRONT...BECOMING WNW 6-8KTS BEHIND THE FRONT...INCREASING TO 8-10KTS AFT 14Z WITH LOW END GUSTS. MEDIUM TO HIGH CONFIDENCE IN CIGS/VSBYS THROUGH THE TAF VALID PERIOD. HIGH CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... HIGH PRESSURE AND DRIER AIR IN THE REGION MONDAY NIGHT THROUGH THURSDAY WILL RESULT IN MAINLY VFR CONDITIONS. RIVER VALLEY FOG WILL STILL BE POSSIBLE AT NIGHT AS WINDS DIMINISH AND COOL AIR MASS DECOUPLES AND MIN TEMPS LOWER INTO THE 40S...ESPECIALLY AT LWB/BCB. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...KK/PM SHORT TERM...WP LONG TERM...CF AVIATION...KK/RAB

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