Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 292059 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 359 PM EST THU JAN 29 2015 .SYNOPSIS... LOW PRESSURE WILL MOVE RAPIDLY EAST ACROSS THE OHIO VALLEY THIS EVENING 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 FRIDAY/... AS OF 320 PM EST THURSDAY... AREA OF LIGHT MIXED WINTRY PRECIPITATION CURRENTLY WEAKENING AND EXITING THE REGION TO THE EAST. A BIT OF A CLEAR SLOT IS MAKING ITS WAY INTO THE REGION IN ADVANCE OF THE APPROACHING COLD FRONT. THIS FRONT IS EXPECTED TO MOVE INTO AND THEN THROUGH THE AREA THIS EVENING. BEHIND IT...NORTHWEST WINDS WILL BEGIN TO INCREASE AN THE UPSLOPE RAIN/SNOW MACHINE WILL INITIATE OVER SOUTHEAST WEST VIRGINIA...SOUTH INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA. THE PRECIPITATION SHOULD TRANSITION TO ALL SNOW BY LATE THIS EVENING. 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 /FRIDAY NIGHT 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 /21Z THURSDAY THROUGH TUESDAY/... AS OF 1235 PM EST THURSDAY... MAINLY VFR CONDITIONS WILL CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON ACROSS THE AREA. THE EXCEPTION WILL BE ALONG A BAND OF PRECIPITATION MOVING ACROSS THE REGION CURRENTLY THAT IS A MIXTURE OF RAIN AND SLEET. SOME ISOLATED...AND TEMPORARY...MVFR CIGS/VSBYS ARE POSSIBLE WITHIN THIS BAND. A COLD FRONT WILL CROSS THE REGION THIS EVENING. EXPECT WINDS TO SHIFT NORTHWEST AND INCREASE SIGNIFICANTLY. RESIDUAL LOW LEVEL MOISTURE ALONG WITH THE UPSLOPE WINDS WILL GENERATE SNOW SHOWERS ACROSS THE MOUNTAINS AND IFR/MVFR CIGS THAT WILL CARRY OVER INTO FRIDAY MORNING. LITTLE OR NO SNOW IS EXPECTED TO PROGRESS EAST OF THE CREST OF THE BLUE RIDGE. DURING THE DAY FRIDAY...SURFACE WILL WILL INCREASE EVEN MORE AS 50KTS AT 850 MB IS EXPECTED TO CROSS THE REGION. ANTICIPATE GUSTS IN THE MOUNTAINS TO BE AROUND 40 KTS AT SOME OF THE HIGHER ELEVATIONS. EXTENDED DISCUSSION... MVFR CIGS MAY LINGER OVER THE MOUNTAINS INTO FRIDAY NIGHT WITH STRONG NW WINDS...AFTER WHICH LOOK FOR IMPROVING CONDITIONS WITH VFR EXPECTED SATURDAY AND SATURDAY NIGHT COURTESY OF HIGH PRESSURE PASSING OVERHEAD THE FIRST HALF OF THE WEEKEND. THE NEXT LOW PRESSURE SYSTEM HEADING OUT OF THE SW STATES WILL BRING A RETURN OF CLOUDS AND SOME PRECIPITATION ON SUNDAY AND MONDAY WITH WIDESPREAD MVFR TO IFR LIKELY. BY TUESDAY...HIGH PRESSURE AND VFR CONDITIONS RETURN TO THE AREA. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND ADVISORY FROM 3 AM TO 9 PM EST FRIDAY FOR VAZ009>014- 016>020-022>024-032>035. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST FRIDAY NIGHT FOR VAZ015. NC...WIND ADVISORY FROM 3 AM TO 9 PM EST FRIDAY FOR NCZ002. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST FRIDAY NIGHT FOR NCZ001-018. WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO NOON EST FRIDAY FOR WVZ508. && $$ SYNOPSIS...DS NEAR TERM...DS SHORT TERM...RCS LONG TERM...MBS AVIATION...DS

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