Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 300528 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1228 AM EST FRI JAN 30 2015 .SYNOPSIS... LOW PRESSURE WILL MOVE RAPIDLY EAST ACROSS THE OHIO VALLEY TONIGHT AND INTO NEW ENGLAND BY FRIDAY MORNING. A SURFACE COLD FRONT WILL TRAIL SOUTH FROM THE LOW...AND WILL SWEEP SOUTHEAST ACROSS THE OHIO VALLEY TONIGHT...THEN THROUGH THE MID ATLANTIC REGION FRIDAY MORNING. HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION FOR FRIDAY NIGHT AND SATURDAY...FOLLOWED BY AN AREA OF LOW PRESSURE WHICH WILL MOVE FROM TEXAS SUNDAY...TO THE MID ATLANTIC COAST BY MONDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 1124 PM EST THURSDAY... MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND DEW POINT TEMPERATURES FOR TONIGHT. SFC TEMPERATURES WERE RUNNING A LITTLE WARMER IN A FEW LOCATIONS...BUT WILL DROP BEHIND THE COLD FRONT. THE COLD FRONT HAS REACH THE MOUNTAINS TONIGHT AND WILL MOVE EAST ACROSS THE REGION FRIDAY MORNING. KFCX 88D SHOWING LIGHT RETURNS ALONG THE WESTERN SLOPES. BOTH THE NAM AND HRRR SUPPORT CURRENT FORECAST WITH UPSLOPE SNOW SHOWERS AND SNOW FLURRIES LATER TONIGHT. INITIALLY EXPECTED SOME RAIN SHOWERS BEFORE TRANSITION OVER TO SNOW TONIGHT. WINTER WEATHER ADVISORIES CONTINUES FOR WESTERN GREENBRIER INTO FRIDAY. WIND ADVISORIES REMAIN ALONG AND WEST OF THE BLUE RIDGE INTO FRIDAY NIGHT. AS OF 715 PM EST THURSDAY... CURRENT FORECAST IS ON TRACK WITH ALL OF THE ACTION YET TO COME A LITTLE BIT LATER THIS EVENING. APPROACHING COLD FRONT IS CURRENTLY ENTERING WEST VIRGINIA AND EASTERN KENTUCKY WHERE WINDS HAVE COME AROUND TO NW AND RADAR SHOWS SOME LIGHT RETURNS BEHIND THE FRONT. TEMPS WILL BE FALLING BEHIND THE FRONT AND EXPECT WE WILL FALL ABOUT 10F BELOW CURRENT VALUES FOR LOWS OF LOWER 30S EAST OF THE RIDGE WITH LOW/MID 20S WEST. THE FRONT SHOULD REACH THE WESTERN SLOPES OF THE APPALACHIANS AROUND 9PM AND START TO KICK OFF UPSLOPE SNOW SHOWERS. CURRENT SNOW ACCUMULATION FORECAST LOOKS GOOD BASED ON MESO MODELS WITH 2 TO 4 INCH ADVISORY CRITERIA SNOW FOR WESTERN GREENBRIER INTO FRIDAY MORNING AND LIGHTER AMOUNTS FURTHER SOUTH ALONG THE WESTERN SLOPES. THE NC MOUNTAINS ARE LOOKING GOOD FOR AROUND 2 INCHES. WINDS ARE CURRENTLY QUITE TAME BUT THAT WILL CHANGE BEHIND THE FRONT. WINDS WILL BECOME NW AND REALLY START TO BLOW AFTER MIDNIGHT WHEN THE WIND ADVISORIES START TO GO INTO EFFECT. GUSTS OF 50 MPH TO 55 MPH CAN BE EXPECTED FOR THE NC MOUNTAINS INTO THE GRAYSON HIGHLANDS...AND 40 MPH TO 50 MPH GUSTS WILL SPREAD NORTH INTO THE BLUE RIDGE OVERNIGHT. THE WINDY CONDITIONS WILL CONTINUE THROUGH FRIDAY BEFORE GRADUALLY SUBSIDING TOMORROW NIGHT. PREVIOUS AFD... NORTHWEST WINDS WILL BEGIN TO INCREASE AND THE UPSLOPE RAIN/SNOW MACHINE WILL INITIATE OVER SOUTHEAST WEST VIRGINIA...SOUTH INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA. OUR LATEST SNOWFALL TOTALS DO NOT DIFFER GREATLY FROM OUR PRIOR FORECAST. ADVISORY LEVEL SNOWS STILL LOOK PROMISING ACROSS WESTERN GREENBRIER COUNTY IN THE TWO TO FOUR RANGE. HAVE INCREASED WESTERN PARTS OF GRAYSON...ASHE...AND WATAUGA COUNTIES INTO THE ONE TO TWO INCH RANGE. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE LOW TO MID 20S ACROSS THE MOUNTAINS WITH READINGS AROUND 30 TO THE LOWER 30S ACROSS THE PIEDMONT. WIND GUSTS ARE EXPECTED TO REACH ADVISORY LEVEL TONIGHT...FIRST ACROSS THE NORTHERN MOUNTAINS NORTH CAROLINA AND THE GRAYSON HIGHLANDS A LITTLE AFTER MIDNIGHT. AS THE NIGHT PROGRESSES...ADVISORY LEVEL GUSTS WILL SPREAD NORTH ACROSS THE HIGHER RIDGES OF SOUTHWEST VIRGINIA...AND THE WESTERN PORTIONS OF WESTERN GREENBRIER COUNTY. THE HIGHER TERRAIN OF GRAYSON...ASHE...AND WATAUGA MAY BE APPROACH GUSTS WITH SPEEDS AT HIGH WIND WARNING CRITERIA FRIDAY MORNING. THE GUSTS WILL WEAKEN JUST SLIGHTLY DURING FRIDAY AFTERNOON...PRIOR TO AN EXPECTED BRIEF INCREASE FRIDAY EVENING. SNOW WILL GRADUALLY COME TO AN END DURING THE DAY...BUT LINGER THE LONGEST ACROSS SOUTHEAST WEST VIRGINIA. HIGH TEMPERATURES WILL RANGE FROM THE MID 20 TO LOWER 30S ACROSS THE MOUNTAINS...WITH MANY OF THESE READINGS OCCURRING EARLY IN THE DAY WITH FALLING TEMPERATURES THEREAFTER. THE PIEDMONT WILL EXPERIENCE HIGHS IN THE UPPER 30S TO LOWER 40S. && .SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... AS OF 240 PM EST THURSDAY... LOW PRESSURE OFF THE NEW ENGLAND COAST AND HIGH PRESSURE SLIDING ACROSS THE OHIO VALLEY WILL KEEP A PRESSURE GRADIENT AND WINDY/GUSTY CONDITIONS ACROSS THE REGION INTO MONDAY EVENING. THROUGH THE NIGHT HIGH PRESSURE EDGES INTO THE AREA WITH SOME LOCATIONS BEING ABLE TO DECOUPLE WHILE BREEZY/GUSTY CONDITIONS REMAIN ACROSS THE MOUNTAINS. MORNING LOWS WITHOUT THE WIND WILL RANGE FROM 5F TO 15F ACROSS THE MOUNTAINS TO AROUND 20F EAST OF THE BLUE RIDGE. IF MIXING CONTINUES INTO SATURDAY MORNING...WIND CHILLS NEAR ZERO ACROSS THE HIGHER ELEVATIONS TO AROUND 10F ABOVE IN THE LOWER ELEVATIONS. IN THE EAST...UPPER TEEN WIND CHILLS LIKELY. HIGH PRESSURE BUILDS OVER THE REGION SATURDAY...THEN SLIDES TO THE SOUTHEAST SATURDAY NIGHT. MOSTLY SUNNY SKIES SATURDAY WITH TEMPERATURES WARMING INTO THE UPPER 30S WEST TO MID 40S EAST. THE NEXT PRECIPITATION MAKER WILL PUSH CLOUDS OVER THE AREA SATURDAY NIGHT WITH LOWS DROPPING JUST BELOW FREEZING. COMPLICATED WEATHER PATTERN WILL BRING PRECIPITATION INTO THE AREA SUNDAY. AN UPPER LEVEL LOW OVER THE SOUTHWEST UNITED STATES WILL THROW ENERGY AND MOISTURE INTO THE PLAINS. AN UPPER LEVEL NORTHERN STREAM TROUGH WILL SWING OUT OF THE ROCKIES SATURDAY NIGHT. A SERIES OF SHORT WAVES WILL TRACK ACROSS THE MID WEST AND EVENTUALLY SPIN UP A SURFACE WAVE OVER THE TENNESSEE VALLEY. ALL THIS ENERGY/MOISTURE WILL TRACK IN ZONAL FLOW AND INTO THE DEPARTING SURFACE RIDGE. THE FIRST SIGNS OF MEASURABLE PRECIPITATION MAY HOLD OFF UNTIL THE AFTERNOON. THE SURFACE LOW AND UPPER LEVEL DYNAMICS COMES ACROSS THE AREA SUNDAY NIGHT AND HAVE RAISED POPS INTO THE HIGH LIKELY CATEGORY. THE TOUGH QUESTION NOW DEALS WITH P-TYPE. TEMPERATURES AND THICKNESSES START COLD ACROSS THE MOUNTAINS FOR PRECIPITATION TO FALL AS SNOW. IF DRY AIR IS LEFT-OVER FROM DEPARTING HIGH...PRECIPITATION FALLING COULD SEND WET BULB TEMPERATURES DOWN BELOW FREEZING (NAM)...KEEPING MOUNTAIN PRECIPITATION AS SNOW AND A COLD RAIN IN THE EAST. IF THE SURFACE LOW BECOMES STRONGER...MORE WARM AIR WILL SURGE INTO THE AREA (GFS) CHANGING SNOW OVER TO RAIN THROUGH THE DAY SUNDAY...THEN COLD AIR ENTERS LATE SUNDAY NIGHT TO CHANGE RAIN BACK TO SNOW. BEING RIGHT IN THE TRACK OF THE LOW AND LIMITED DENDRITE GROWTH NOT SUPPORTING STAYING ALL SNOW...WE WILL LEAN TO A MOSTLY RAIN EVENT SUNDAY...CHANGING OVER TO SNOW WHEN THE COLD FRONT PASSES SUNDAY NIGHT. ALSO...WE ARE NOT LOOKING AT A WEDGE LINGERING IN THE REGION...THEREFORE HIGHLY CONFIDENT PRECIPITATION WILL BE RAIN OR SNOW...NOT A MIXTURE OR CHANGE OVER TO FREEZING RAIN/SLEET. && .LONG TERM /MONDAY THROUGH THURSDAY/... 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 /05Z FRIDAY THROUGH TUESDAY/... AS OF 1215 AM EST FRIDAY... THE STRONG ADVERTISED ALBERTA CLIPPER COLD FRONT MOVING RAPIDLY THROUGH THE WESTERN PART OF THE CWA AT THIS HOUR...NEAR BCB AND ALREADY THROUGH LWB/BLF. VERY QUICKLY CIGS DROP INTO THE MVFR/IFR RANGE BEHIND THE FRONT WITH MIXED PCPN...WHICH SHOULD RAPIDLY CHANGE TO SNOW WITH STRONG LOW-LEVEL COLD ADVECTION. ALONG AND EAST OF THE BLUE RIDGE...WINDS LIGHT AND VARIABLE WITH MOSTLY LOW END VFR CIGS AT THIS HOUR. MODELS NOW DEPICTING A WAVE THAT WILL RIDE ALONG THE FRONT...WHICH COULD SLIGHTLY DELAY ITS PROGRESS INTO THE PIEDMONT AND FURTHERMORE BRING A WAVE OF -SHRA TO BCB/ROA BEFORE THE COLD FRONT ARRIVES OR SHORTLY THEREAFTER. HAVE THUS INTRODUCED THESE CHANGES TO THE TAFS...SLIGHTLY DELAYING THE ARRIVAL OF THE FRONT INTO ROA/LYH/DAN AND ALSO INTRODUCING -SHRA TO BCB/ROA THAT WERE NOT IN THE 00Z TAFS. UPSLOPE -SHSN SHOULD CONTINUE TO BE ENHANCED WEST OF THE BLUE RIDGE OVERNIGHT INTO EARLY FRI...WITH OCCASIONAL MVFR TO BRIEFLY IFR VSBYS AND IFR-LIFR CIGS. CONDITIONS SHOULD BEGIN TO IMPROVE AFT 14Z WITH JUST FLURRIES OR OCCASIONAL -SHSN THROUGH THE EARLY AFTERNOON WEST OF THE BLUE RIDGE. EXPECT MVFR CIGS TO HOLD MUCH OF THE DAY WEST OF THE BLUE RIDGE...BUT CLOUDS SHOULD SCATTER OUT TO THE EAST. EXPECT VFR CIGS AROUND 22Z BLF/LWB/BCB...BECOMING MOSTLY SKC OR JUST SCT ALL SITES AFT 22Z. MAIN CONCERN THROUGH THE TAF VALID PERIOD WILL BE STRONG...GUSTY NORTHWEST WINDS. WITH A 50KT NORTHWESTERLY LLJ OVER THE REGION LATE TONIGHT/EARLY FRI AS A TIGHT PRESSURE GRADIENT DEVELOPS BETWEEN THE ADVANCING CANADIAN HIGH AND THE DEPARTING SFC LOW NORTHEAST U.S...30-40KT WIND GUSTS WILL BE POSSIBLE LATE TONIGHT AND THROUGH EARLY AFTERNOON FRI. SUSTAINED WINDS SHOULD BE MAINLY IN THE 15-25KT RANGE. WINDS REMAIN GUSTY EVEN INTO FRI EVENING...BUT SHOULD DROP BELOW 25KTS FAIRLY QUICKLY AFT 02Z. WINDS OVERALL WILL AVERAGE 10KTS LESS ACROSS THE PIEDMONT. MEDIUM CONFIDENCE IN CIGS AND VSBYS THROUGH 14Z...THEN MEDIUM TO HIGH CONFIDENCE. MEDIUM TO HIGH CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID PERIOD. EXTENDED DISCUSSION... WINDS WILL DIMINISH FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE REGION FROM THE WEST. ANY REMAINING LOW CLOUDS LINGERING ACROSS EASTERN WV SHOULD DISSIPATE...WITH VFR CIGS EXPECTED FRI NIGHT AND SAT. 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 MOSTLY WINTER PRECIPITATION WITH THIS EVENT...WHILE THE SOUTHERN AREAS SHOULD SEE MOSTLY RAIN. IN BETWEEN...LOCATIONS SUCH AS BCB/ROA/LYH...COULD SEE A MIX OF RAIN AND SNOW. MOUNTAIN SNOW SHOWERS WITH MVFR CIGS/VSBYS WILL CONTINUE INTO MON...WITH STRONG AND GUSTY WINDS ALL AREAS BY MONDAY AFTERNOON. IMPROVING CONDITIONS ARE EXPECTED BY TUESDAY. && .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. NC...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR NCZ002. WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ001-018. WV...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR WVZ508. && $$ SYNOPSIS...DS NEAR TERM...DS/KK/MBS SHORT TERM...RCS LONG TERM...MBS AVIATION...DS/RAB

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