Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 302012 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 312 PM EST FRI JAN 30 2015 .SYNOPSIS... COLD HIGH PRESSURE WILL GRADUALLY BUILD EAST INTO THE AREA TONIGHT AND ABOUT OVERHEAD ON SATURDAY. THIS WILL ALLOW FOR DRIER WEATHER UNDER DIMINISHING WINDS LATER TONIGHT INTO SATURDAY. ANOTHER AREA OF LOW PRESSURE WILL MOVE OUT OF THE SOUTHWESTERN UNITED STATES ON SATURDAY...CROSSING THE CENTRAL PART OF THE NATION SUNDAY...AND REACHING THE EAST COAST BY MONDAY MORNING. && .NEAR TERM /THROUGH SATURDAY/... AS OF 215 PM EST FRIDAY... FINAL WAVE ALOFT WITHIN THE BASE OF THE 5H TROUGH WILL PIVOT EAST OF THE REGION THIS EVENING ALLOWING FOR A QUICK DECREASE IN MOISTURE AS BETTER SUBSIDENCE ARRIVES AHEAD OF HIGH PRESSURE TO THE WEST. THIS SHOULD BRING AN END TO MOST ACCUMULATING UPSLOPE SNOW ACROSS THE FAR NW EARLY ON ESPCLY GIVEN THE PASSING OF THE COLDEST AIR AT 85H AND SOME GRADUAL DECREASE IN THE JET ALOFT THROUGH MIDNIGHT. HOWEVER WILL LIKELY STILL SEE SOME SNOW SHOWERS OR FLURRIES GIVEN LINGERING LOW LEVEL MOISTURE SO KEEPING SO LOW POPS OR FLURRY MENTION GOING NW THIRD THROUGH ABOUT MIDNIGHT FOR NOW. OTHERWISE APPEARS THE STRONGEST OF THE SURFACE WINDS WILL EXIT AFTER DARK WITH PERHAPS A SECOND SURGE ACROSS THE NORTH CAROLINA MOUNTAINS THIS EVENING BEFORE SPEEDS DROP BELOW CRITERIA OVERNIGHT. HOWEVER STILL GUSTY ON THE RIDGES GIVEN THE SLOWNESS OF THE SURFACE HIGH TO SHIFT EAST AND THE FORECAST REMAINING PRESSURE GRADIENT OFF MOST MODELS. SHOULD FINALLY SEE SKIES CLEAR FROM THE BLUE RIDGE EAST THIS EVENING AND ALL EXCEPT THE FAR NW SLOPES LATE GIVEN LINGERING MOISTURE OFF THE NAM. EXPECT ENOUGH COLD ADVECTION TO CAUSE TEMPS TO FALL INTO THE TEENS WITH A FEW SINGLE DIGITS MOUNTAINS...AND UPPER TEENS TO LOW 20S EAST DESPITE CONTINUED MIXING FOR MUCH OF THE AREA. THIS MAY BRING A FEW AREAS INCLUDING THE HIGHER ELEVATIONS OF GREENBRIER AND BATH INTO WIND CHILL ADVISORY CRITERIA BY MORNING. SURFACE HIGH BUILDS OVERHEAD SATURDAY UNDER DEVELOPING ZONAL FLOW ALOFT ALLOWING FOR LIGHTER WINDS AND WARMER TEMPS GIVEN 85H WARMING. SOME INCREASE IN WARM ADVECTION MID/HIGH CLOUDS LIKELY BY MID/LATE AFTERNOON UNDER THE FAST FLOW ALOFT FROM THE WEST BUT OVERALL MOSTLY SUNNY. WITH WEAK DOWNSLOPE/DRY AIR...WENT ON THE WARMER SIDE OF MOST ESPCLY EAST WHERE LOW/MID 40S LIKELY WHILE KEEPING THE WEST MAINLY 30S TO AROUND 40 GIVEN THE 85H NW TRAJECTORY. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 240 PM EST FRIDAY... A LARGE AREA OF HIGH PRESSURE WILL MOVE SOUTH ACROSS THE REGION SATURDAY AND BE CENTERED NEAR THE SOUTH CAROLINA COAST SUNDAY MORNING. THIS HIGH PRESSURE WILL STILL HAVE AN INFLUENCE ON OUR WEATHER KEEPING DRY AIR...DEW POINTS IN THE TEENS...IN THE REGION. A WARM FRONT ALOFT WILL TRACK ACROSS THE OHIO VALLEY EARLY SUNDAY MORNING. ISENTROPIC LIFT MAY GENERATE PRECIPITATION ACROSS THE GREENBRIER VALLEY TO THE ALLEGHANY HIGHLANDS SUNDAY MORNING AS THIS WARM FRONT TRACKS NORTH TO THE MASON-DIXON LINE DURING THE DAY SUNDAY. ANY PRECIPITATION FALLING INTO THIS DRY AIR WILL KEEP THE AIR COLUMN COLD ENOUGH FOR LIGHT SNOW TO FALL IN THE MORNING. THIS PRECIPITATION WILL MOVE NORTH OF THE AREA BY NOON. THE ENTIRE AREA WILL BE IN THE WARM SECTOR SUNDAY AFTERNOON WITH TEMPERATURES WARMING INTO THE 40S WEST AND LOWER 50S EAST. ALSO ON SUNDAY...A NORTHERN STREAM TROUGH WILL COME OUT OF THE ROCKIES SPAWNING A SURFACE LOW OVER THE RED RIVER VALLEY. THIS LOW WILL THEN TRACK TO THE OZARKS SUNDAY MORNING...THEN OVER THE SOUTHERN OHIO VALLEY IN THE AFTERNOON. THE CURRENT TRACK OF THIS LOW WILL KEEP THE AREA IN A WARM AIRMASS THROUGH THE DAY SUNDAY. SHORT WAVES AND SOUTHEAST FLOW WILL BRING LIGHT SHOWERS INTO THE AREA DURING THE AFTERNOON. PRECIPITATION FALLING IN THE AFTERNOON SHOULD KEEP TEMPERATURES MILD WHILE DEW POINTS AND WET BULB INCREASE INTO THE 30S. DEPENDING ON HOW FAST PRECIPITATION MOVES INTO THIS DRY AIR ...IT MAY START OUT AS A BRIEF PERIOD OF A SNOW/SLEET MIX...BUT WILL TRANSITION OVER TO A COLD RAIN. MODELS CONTINUE TO TRACK THE SURFACE LOW NORTH OF THE AREA AND ACROSS NORTHERN VIRGINIA/MARYLAND SUNDAY NIGHT. SOUTHERLY FLOW WILL CONTINUE TO BRING WARM AIR INTO THE REGION WITH 85H TEMPERATURES 4C OR WARMER. THE COLD FRONT DOES NOT ENTER RNK MOUNTAIN COUNTIES UNTIL EARLY MONDAY MORNING. THEREFORE WILL DELAY CHANGE-OVER TO SNOW UNTIL AFTER MIDNIGHT ACROSS SOUTHEASTERN WEST VIRGINIA. THE SURFACE LOW TRACKS OFF THE MID ATLANTIC COAST MONDAY MORNING WITH PRECIPITATION ENDING OVER THE PIEDMONT BY NOON. THE UPPER LEVEL PORTION OF THIS SYSTEM WILL TRACK OVER THE FORECAST AREA DURING THE AFTERNOON. THE DEFORMATION ZONE AND BRIEF UPSLOPE WILL BRING SCATTERED SNOW SHOWERS TO THE MOUNTAINS THROUGH THE AFTERNOON...THEN HIGH PRESSURE MOVES OVER THE OHIO VALLEY SHUTTING OFF MOISTURE FEED. FOLLOWING THE FRONT...A SURGE OF ARCTIC AIR WILL SEND TEMPERATURES DOWN THROUGH THE DAY MONDAY. MORNING HIGHS IN THE 30F-35F RANGE IN THE WEST TO A LATE MORNING MAX IN THE EAST IN THE M/U 40S. ALSO BEHIND THE FRONT...STRONG PRESSURE RISES AND COLD AIR ADVECTION WILL BRING HIGH WINDS AND GUSTY CONDITIONS TO THE AREA. ONLY THING LACKING FOR A HIGH CONFIDENCE HIND WIND WATCH/WARNING IS A STRONG LOW LEVEL JET. MODELS ARE ONLY DISPLAYING A 40KT JET OVER THE BLUE RIDGE WITH HIGHER SPEEDS TO THE NORTH. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 330 PM EST THURSDAY... TEMPERATURES BELOW NORMAL THROUGH THE EXTENDED...TRENDING TO MUCH BELOW NORMAL TOWARD THE END OF NEXT WEEK. MODELS KEEP THINGS PROGRESSIVE AND ARE CONSISTENT IN PHASING THE UPPER LEVEL SPLIT FLOW PATTERN INTO A LONG WAVE WESTERN TROF/EASTERN RIDGE PATTERN. THIS WILL OPEN THE DOOR FOR A SHOT OF ARCTIC AIR AS WE GET TOWARD THE END OF THE PERIOD. WE START THE PERIOD WITH A COASTAL LOW OFF THE MIDDLE ATLANTIC COAST PULLING AWAY FROM THE REGION...LEAVING US WITH COLDER AIR MOVING IN AND RESIDUAL NORTHWEST UPSLOPE FLOW SNOW SHOWERS WEST OF THE BLUE RIDGE. THE SNOW SHOWERS COME TO AN END MONDAY NIGHT AS HIGH PRESSURE BUILDS IN FROM THE OHIO VALLEY AND BRINGS US QUIET AND COLD WEATHER FOR TUESDAY AND TUESDAY NIGHT. THE NEXT CHANCE FOR PRECIPITATION COMES ON WEDNESDAY AS DEEPENING LOW PRESSURE SYSTEM IS DRIVEN BY A VIGOROUS SHOT WAVE THROUGH THE GREAT LAKES REGION AND INTO CANADA. THIS WILL SWING A COLD FRONT THROUGH THE REGION...OPENS THE DOOR TO ARCTIC HIGH PRESSURE BUILDING IN FROM THE MIDWEST. MODEL RUN TO RUN VARIABILITY IN THE EXTENDED HAS BEEN QUITE HIGH RECENTLY AND WHILE EVOLUTION OF THE OVERALL SYNOPTIC PATTERN SEEMS SOLID...DO NOT HAVE A LOT OF CONFIDENCE IN SPECIFICS FROM ANY OF THE INDIVIDUAL SOLUTIONS. THE EURO IS QUITE AGGRESSIVE IN DIGGING THE EASTERN TROF AND DEVELOPS A COASTAL LOW MOVING OUT OF THE GULF WITH A CHANCE OF WINTRY PRECIPITATION FOR OUR NORTH AND WEST AREAS...WHILE THE GFS/NAEFS IS LESS AMPLIFIED AND DOES NOT ADVERTISE A COASTAL LOW AND KEEPS US MOSTLY DRY. WILL HAVE TO WAIT AND SEE HOW THIS ALL PLAYS OUT IN LATER MODEL RUNS BUT FOR NOW WILL SHADE THE FORECAST TOWARD THE DRIER GFS/NAEFS. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... AS OF 1210 PM EST FRIDAY... MAIN CONCERN CONTINUES WITH STRONG NORTHWEST WINDS THIS AFTERNOON AND EVENING. WITH A 50KT NORTHWESTERLY JET ALOFT OVER THE REGION... EXPECT 25-40KT SURFACE WIND GUSTS...ESPECIALLY THIS AFTERNOON. WINDS WILL DIMINISH SOMEWHAT AFTER SUNSET...BUT WILL NOT COMPLETELY DIMINISH UNTIL HIGH PRESSURE MOVES OVERHEAD SATURDAY. MOUNTAIN SNOW SHOWERS WILL PERSIST AS WELL INTO LATE THIS AFTERNOON WITH MVFR/OCNL IFR LIKELY ACROSS THE MOUNTAINS...IMPACTING KBLF/KLWB/KBCB. FLURRIES MAY DRIFT AS FAR EAST AS THE BLUE RIDGE...BUT OVERALL VFR WITH LATE AFTERNOON CLEARING IS EXPECTED EAST OF THE BLUE RIDGE PER STRONG SUBSIDENCE AND DRYING. WINDS WILL DIMINISH FOR SATURDAY AS HIGH PRESSURE MOVES INTO THE REGION FROM THE WEST. ANY REMAINING LOW CLOUDS LINGERING ACROSS EASTERN WEST VA SHOULD DISSIPATE...WITH MAINLY VFR REGION WIDE FOR SATURDAY. EXTENDED DISCUSSION... THE NEXT LOW PRESSURE SYSTEM HEADING OUT OF THE SW STATES WILL BRING A RETURN OF CLOUDS AND PRECIPITATION ON SUNDAY WITH WIDESPREAD MVFR TO IFR CIGS/VSBYS LIKELY WITHIN THIS TIME FRAME. THE NORTHERN SECTIONS OF THE CWA WILL LIKELY SEE SOME WINTER PRECIPITATION WITH THIS EVENT...WHILE THE SOUTHERN AREAS SHOULD SEE MOSTLY RAIN. IN BETWEEN...LOCATIONS SUCH AS KBCB/KROA/KLYH...COULD SEE A BRIEF MIX OF RAIN AND SNOW AT THE ONSET WITH MOSTLY A RAIN EVENT OVERALL. MOUNTAIN SNOW SHOWERS WITH MVFR CIGS/VSBYS WILL CONTINUE INTO MONDAY...WITH STRONG AND GUSTY WINDS ALL AREAS BY MONDAY AFTERNOON. IMPROVING CONDITIONS ARE EXPECTED BY TUESDAY WITH VFR RETURNING FOR ALL LOCATIONS UNDER HIGH PRESSURE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR VAZ009>014- 016>020-022>024-032>035. WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ015. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST SATURDAY FOR VAZ020. NC...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR NCZ002. WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ001-018. WV...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST SATURDAY FOR WVZ507-508. && $$ SYNOPSIS...JH/PM NEAR TERM...JH SHORT TERM...RCS LONG TERM...MBS AVIATION...JH/PM

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