Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 100039
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
739 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 730 PM EST TUESDAY...

FORECAST PRETTY MUCH ON TRACK THIS EVENING WITH NARROW BANDS OF
MAINLY LIGHT SNOW SHOWERS PUSHING ACROSS THE NEW RIVER VALLEY WITH
FLURRIES AS FAR EAST AS THE FOOTHILLS.

UPPER VORT MOVING ACROSS EASTERN WV TRACKS ENE INTO NRN VA BY
DAWN. MAIN AXIS OF UPPER LEVEL ENERGY SHIFTS TO OUR SOUTH
OVERNIGHT. SHOULD SEE MAINLY NW FLOW SNOW SHOWERS AT TIMES
OVERNIGHT WITH ANOTHER 1-3 INCHES POSSIBLE IN WRN GREENBRIER AND
AN INCH OR TWO OVER THE HIGHER TERRAIN OF NC/FAR SW VA...DUSTING
TO THE NEW RIVER VALLEY.

PREVIOUS DISCUSSION FROM LATE AFTERNOON...

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 PRECIP 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 /01Z WEDNESDAY THROUGH SUNDAY/...
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.

&&

.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/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...JM/RCS


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