Area Forecast Discussion
Issued by NWS Blacksburg, VA

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812 FXUS61 KRNK 100004 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 704 PM EST TUE FEB 9 2016 .SYNOPSIS... A STRONG CYCLONE IN THE UPPER LEVELS OF THE ATMOSPHERE IS CENTERED OVER THE OHIO VALLEY. THIS FEATURE WILL REMAIN NEARLY STATIONARY THROUGH WEDNESDAY BEFORE SLOWLY MOVING EAST. WEAK UPPER LEVEL IMPULSES WILL MOVE ACROSS THE MOUNTAINS THROUGH WEDNESDAY NIGHT RESULTING IN PERSISTENT SNOW SHOWER AND FLURRY ACTIVITY. TEMPERATURES WILL REMAIN BELOW NORMAL FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 400 PM EST TUESDAY... THE COLD UPPER LEVEL LOW WILL EDGE EASTWARD FROM THE OHIO VALLEY THIS EVENING TO THE NORTHERN MID ATLANTIC REGION ON WEDNESDAY. WE WILL CONTINUE TO SEE SNOW SHOWERS ACROSS THE MOUNTAINS THROUGH THE DAY TOMORROW WITH HIGHEST ACCUMULATIONS ALONG WESTERN SLOPES. WHILE THE SOUTHERN APPALACHIANS REMAIN UNDER THE INFLUENCE OF THE CLOSED LOW...EMBEDDED SHORTWAVES WILL PIVOT OVER THE AREA BRING LIGHT TO SOMETIMES MODERATE SNOW SHOWERS TO THE MOUNTAINS POSSIBLE SPILLING OVER THE BLUE RIDGE OVERNIGHT. THE ONE SHORT WAVE AXIS THAT CAN BE SEEN GENERATING BANDS OF PRECIPIATION ACROSS THE TENNESSEE VALLEY AND INTO GEORGIA THIS AFTERNOON...WILL MOVE OVER THE REGION TOMORROW. NORTHWEST TO SOUTHEAST ORIENTED NARROW BANDS OF SNOW WILL COME ACROSS THE AREA. SOME OF THESE BANDS COULD DROP AN INCH OR TWO OF SNOW WITHIN AN HOUR. TIMING AND LOCATION OF THESE BANDS WILL BE DIFFICULT AS HIRES SHORT RANGE MODELS ARE HAVING TROUBLE WITH SNOW EAST OF WESTERN SLOPES WITH THIS EVENT. ADDITIONAL ACCUMULATIONS WILL RANGE FROM 8 INCHES ACROSS WESTERN GREENBRIER TO 3-6 INCHES ALONG SLOPES OF SOUTHWESTERN VIRGINIA AND NORTHWESTERN NORTH CAROLINA. OUTSIDE OF THESE WESTERN SLOPES 1-3 INCHES ARE POSSIBLE TO ABOUT AN HALF TO ONE INCH ACROSS THE NEW RIVER VALLEY AND ALLEGHANY HIGHLANDS. THE SHORT WAVES ARE STRONG ENOUGH TO CARRY SNOW EAST OF THE BLUE RIDGE WITH A DUSTING TO HALF AN INCH POSSIBLE IN THE FOOTHILLS AND FLURRIES IN THE PIEDMONT. WINDS THROUGH THE PERIOD WILL REMAIN BREEZY AND GUSTY. MODERATE PRESSURE RISES OVER THE NORTH CAROLINA HIGH COUNTY COULD BRING GUSTS UP TO 40 MPH WEDNESDAY AFTERNOON. THE COMBINATION OF WINDS AND COLD TEMPERATURES WILL PRODUCE WIND CHILL VALUES WEDNESDAY MORNING IN THE SINGLE DIGITS ACROSS THE MOUNTAINS AND LOWER TEENS EAST OF THE BLUE RIDGE. ACTUAL LOWS TONIGHT WILL RANGE FROM 10F- 20F WEST TO LOWER 20S EAST. WITH ARCTIC AIR CONTINUING TO MOVE IN TOMORROW...HIGH TEMPERATURES WILL ONLY WARM INTO THE TEENS TO LOWER 20S WEST AND 30S EAST. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... AS OF 230 PM EST TUESDAY... DEEP UPPER TROF OVER THE EASTERN UNITED STATES THROUGH THURSDAY. A CLOSED UPPER LOW WITH 500 MB HEIGHTS BELOW 500 DM OVER SOUTHEAST CANADA WILL KEEP PERSISTENT NORTHWEST JET OVER THE AREA INTO SATURDAY. VORTICITY ADVECTION AND COLDEST AIR ALOFT MOVE NORTHEAST OF THE FORECAST AREA BY THURSDAY AFTERNOON. 4KM AND 12KM NAM AS WELL AS THE GFS SUGGEST SOME BIG BREAKS IN THE CLOUD COVER...EVEN OVER THE MOUNTAINS ON THURSDAY. BUT MAY TAKE UNTIL LATE IN THE DAY FOR SOUTHWEST VIRGINIA TO SEE THE CLEARING. CLIPPER TYPE SHORT WAVE ON THE WESTERN WIDE OF THE DEEP TROUGH TRACKS FROM MISSOURI INTO THE CAROLINAS ON FRIDAY. STILL SOME DIFFERENCES IN THE MODELS WITH THE TIMING AND POSITION OF THIS WAVE AND WITH ANY DEVELOPMENT OF PRECIPITATION. VERY COLD 850 MB AIR IN THE -18 TO -20 RANGE OVER THE UPPER MISSISSIPPI VALLEY THIS MORNING WILL REACH THE COUNTY WARNING AREA BY THURSDAY MORNING. AFTER THE SHORT WAVE GOES BY ON FRIDAY...EVEN COLDER AIR AT 850 MB ADVECTS INTO THE AREA...ALTHOUGH ECMWF 00Z RUN NOT AS COLD AS 00Z/08 RUN. LOW LEVEL JET ALSO PICKS UP TO AROUND 40 KNOTS ON FRIDAY NIGHT. THIS WILL PRODUCE PRECIPITATION IN THE FAVORED WESTERN UPSLOPE AREAS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 150 PM EST TUESDAY... BOTH THE ECMWF AND THE 12Z GFS HAVE 850 MB TEMPERATURES DROPPING INTO THE -22 TO -24 RANGE SATURDAY NIGHT BEFORE THE UPPER TROF MOVES NORTHEAST LATE THIS WEEKEND WITH WEAK 500 MB RIDGING OVER THE MID ATLANTIC STATES SUNDAY. MODELS THEN HAVE THE NEXT SHORT WAVE TROF REACHING THE AREA FOR MONDAY. THIS SHORT WAVE WILL BRING DEEPER MOISTURE...STRONG WARM AIR ADVECTION...AND A CHANCE OF PRECIPITATION BACK INTO THE FORECAST AREA ON SUNDAY NIGHT AND MONDAY. AT THE SURFACE LOW PRESSURE WILL PASS THROUGH THE SOUTHEAST UNITED STATES AND HIGH PRESSURE WILL REACH THE COUNTY WARNING AREA ON SUNDAY. && .AVIATION /00Z WEDNESDAY THROUGH MONDAY/...
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AS OF 645 PM EST TUESDAY... ONLY MINOR CHANGES MADE TO THE TAF FORECAST THIS ROUND. OVERALL...CONFIDENCE IS HIGH ON LOCATIONS IMPACTED BY VARIABLE CIGS/VSBYS DUE TO FAIRLY CONSISTENT NW FLOW SNOW BANDS THROUGH MUCH OF THE PERIOD. LOWER CONFIDENCE IN PLACE ON THE EXACT TIMING OF WHEN THE SNOW BANDS WILL IMPACT EACH WESTERN AIRPORT SITE. IN GENERAL...EXPECT IMPACTS TO BE HEAVIEST OVERNIGHT TUE THROUGH WED MORNING...WITH AN ADDITIONAL INTENSIFICATION OF SNOW WEDNESDAY EVENING. PERSISTENT ACCUMULATIONS OF SNOW ALONG THE WESTERN SLOPES OF THE APPALACHIANS IS EXPECTED THROUGH THE PERIOD. MVFR AND OCCASIONAL IFR CIGS AND VSBYS WILL BE FOUND ACROSS THE MOUNTAINS WITH MAINLY VFR CONDITIONS EAST OF THE BLUE RIDGE. CAN`T RULE OUT STRAY SNOW SHOWERS OR FLURRIES MAKING IT EAST OF THE BLUE RIDGE ASSOCIATED WITH LOCAL MVFR...BUT COVERAGE DOES NOT WARRANT INCLUSION IN THE KLYH OR KDAN TAF ATTM. CURRENT WEATHER PATTERN WILL PERSIST THROUGH WEDNESDAY PER NEARLY STATIONARY UPPER LEVEL LOW WHICH IS CENTERED OVER THE OHIO VALLEY. WINDS DURING THE PERIOD WILL PRIMARILY BE OUT OF THE WEST TO NORTHWEST...MAGNITUDES OF 8 TO 15 KTS SUSTAINED WITH OCCASIONAL GUSTS OF 15 TO 25 KTS. EXTENDED DISCUSSION... SUB-VFR SHOULD BECOME MORE CONFINED TO THE MOUNTAINS AND WESTERN SLOPES INTO THURSDAY WITH PRIMARY AREA OF MVFR/IFR CONDITIONS CONFINED TO THE WEST...UPSLOPE...SIDE OF THE APPALACHIAN MOUNTAINS. THIS WILL PRIMARILY IMPACT KBLF/KLWB WITH MAINLY VFR CONDITIONS EAST OF THE HIGHER MOUNTAIN RIDGES INTO CENTRAL AND EASTERN VA/NC. CONDITIONS SHOULD BRIEFLY RETURN TO MAINLY VFR THURSDAY NIGHT AS WEAK HIGH PRESSURE BUILDS IN AND MOISTURE DECREASES. ANOTHER CLIPPER SYSTEM POSES TO MOVE ACROSS THE AREA FRIDAY...BRINGING THE POTENTIAL FOR SUB-VFR CONDITIONS TO THE WEST. VFR CONDITIONS SHOULD RETURN FOR MUCH OF THE WEEKEND...PRIOR TO THE ARRIVAL OF AN ADDITIONAL WEATHER SYSTEM...BRINGING THE THREAT FOR SUB VFR CONDITIONS AGAIN MONDAY.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR VAZ007- 009>012-015-019-020. NC...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR NCZ001-018. WV...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR WVZ042>044- 507. WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR WVZ043-508. && $$ SYNOPSIS...RCS NEAR TERM...RCS SHORT TERM...AMS LONG TERM...AMS AVIATION...JM/RCS

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