Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 270454
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1154 PM EST THU FEB 26 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA OVERNIGHT. COLD HIGH PRESSURE
WILL BUILD IN BEHIND IT...AND BE ACROSS OUR AREA THROUGH SATURDAY.
SUNDAY THROUGH AT LEAST THE MIDDLE OF NEXT WEEK...A SERIES OF LOW
PRESSURE SYSTEMS HAVE THE POTENTIAL TO BRINGING MORE ROUNDS OF
PRECIPITATION TO OUR AREA...AND TEMPERATURES ON AVERAGE WILL BE
MILDER THAN THIS WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
AS OF 1145 PM EST THURSDAY...

FOG/FREEZING FOG IN PATCHY AREAS IN THE PIEDMONT AND SOME OF THE
NC FOOTHILLS WILL OCCUR THROUGH THE NIGHT. SPS AND WINTER WX
ADVISORY COVERS ANY BLACK ICE.

NOT EXPECTING TOO MUCH SNOW SHOWERS PER LIMITED MOISTURE DEPTH IN
THE WEST BUT WILL SEE A FEW SNOW SHOWERS AROUND THROUGH DAWN.

NO MAJOR CHANGES OVERALL TO TEMPS...BUT DID LOWER SKY COVER SOME
IN THE EAST AS DOWNSLOPE AND DRIER AIR SHOULD ERODE THE LOW DECK.



PREVIOUS VALID DISCUSSION...
A WINTER WEATHER ADVISORY REMAINS FOR BLACK ICE FOR OUR NORTH
CAROLINA COUNTIES VIA OUR WORKING POLICY WITH THAT STATE. FOR
SOUTHWEST VIRGINIA AND SOUTHEAST WEST VIRGINIA...A SPECIAL WEATHER
STATEMENT HIGHLIGHTING THE BLACK ICE WAS ISSUED.

EXPECT INCREASING NORTHWEST WINDS...THAT WILL BE FULLY REALIZED
DURING THE DAY FRIDAY AFTER THE BREAKING OF THE NOCTURNAL
INVERSION. COLDER AND LOWER DEW POINT AIR WILL WORK ITS WAY INTO
THE AREA OVERNIGHT.

A WEAK DISTURBANCE WILL RIDE PIGGY BACK WITH THE FRONT...AND BRING
THE POTENTIAL FOR SOME LIGHT PRECIPITATION TO AREAS EAST OF THE
CREST OF THE BLUE RIDGE...WHERE NORMAL THE IMPACT OF DOWNSLOPING
WIND WOULD LIMIT IF NOT COMPLETELY RULE OUT THE POTENTIAL FOR
PRECIPITATION. THIS DISTURBANCE IS EXPECTED TO BRING A SLIGHT CHANCE
OF PRECIPITATION TO AREAS NEAR THE NC/VA BORDER EAST OF THE
FOOTHILLS. THIS SATURATION WITHIN THIS AREA WILL BE LIMITED TO A
NARROW BAND BETWEEN 850 MB AND THE SURFACE. THE COLDEST TEMPERATURE
WITHIN THIS BAND WILL RANGE FROM ROUGHLY -8 TO -11 C. WITH VERY
LIMITED OPPORTUNITIES FOR DENDRITIC GROWTH...THE PRECIPITATION
FOR THIS PART OF THE FORECAST AREA IS MORE LIKELY TO BE FREEZING
RAIN...RATHER THAN SNOW. ALTHOUGH WITH -10 TO -11 C AS A COLD
LIMIT...WE CANNOT RULE OUT AT LEAST A LITTLE LIGHT SNOW WITHIN THE
MIX.

ON FRIDAY...NORTHWEST FLOW ALOFT AND INCREASING NORTHWEST SURFACE
WINDS WILL HAVE THE IMPACT OF A DOWNSLOPING COMPONENT THAT WILL
GRADUALLY ERODE THE CLOUD COVER EAST OF THE CREST OF THE BLUE RIDGE.
CLOUDS ACROSS THE MOUNTAINS WILL BE LESS LIKELY TO ERODE AS
FAST...AND UPSLOPE SNOW SHOWERS WILL CONTINUE...BUT TREND TOWARDS
DECREASING COVERAGE AND INTENSITY. HIGH TEMPERATURES TOMORROW WILL
RANGE FROM THE LOW TO MID 20S ACROSS THE MOUNTAINS WITH AROUND 30 TO
UPPER 30S ACROSS THE PIEDMONT.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 320 PM EST THURSDAY...

ZONAL PATTERN AT 500 MB THROUGH SUNDAY WITH NO SIGNIFICANT SHORT
WAVES THROUGH THE PERIOD. MID AND HIGH LEVEL CLOUDS MOVE IN FROM THE
WEST ON FRIDAY NIGHT AND SATURDAY. TRULY DEEP MOISTURE FILLS IN
ACROSS THE FORECAST AREA ON SATURDAY NIGHT AND SUNDAY. FRIDAY
NIGHT HAS THE POTENTIAL TO HAVE MINIMUM TEMPERATURES BELOW
GUIDANCE DUE TO SNOW COVER AND LIGHT WINDS. HOWEVER...CLOUD COVER
MAY COUNTERACT THAT COOLING. LEANED TOWARD BIAS CORRECTED ECMWF
GUIDANCE FOR LOWS ON FRIDAY NIGHT THEN MAV NUMBERS FOR SATURDAY
THROUGH SUNDAY.

HIGH PRESSURE THAT WILL BE CENTERED OVER THE OHIO VALLEY ON FRIDAY
NIGHT WILL MOVE EAST AND WEDGE DOWN THE EAST SIDE OF THE
APPALACHIANS ON SATURDAY AND SUNDAY. SFC AND LOW LEVEL WINDS WILL
HAVE AND EASTERLY COMPONENT BUT AT 850MB THE HIGH IS OFF THE
SOUTHEAST COAST AND FLOW AROUND THE HIGH BRINGS MOISTURE RIGHT
OUT OF THE GULF AND ADVECTS WARMER TEMPERATURES INTO THE REGION.
850MB TEMPERATURES RISE ABOVE ZERO ON SATURDAY NIGHT AND SUNDAY.
THE NAM IS MUCH FASTER THAN THE GFS/ECMWF BRINGING PRECIPITATION
BACK INTO THE COUNTY WARNING AREA ON SUNDAY. WILL KEEP BEST CHANCE
OF PRECIPITATION IN THE WESTERN COUNTY WARNING AREA LATE ON
SUNDAY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 315 PM EST THURSDAY...

SHOWER ACTIVITY WILL INCREASE SUNDAY NIGHT AS ANOTHER COLD FRONT
APPROACHES THE REGION FROM THE WEST. INCREASED CLOUD COVER AND
SOUTHWESTERLY WINDS WILL MAINTAIN WARMER OVERNIGHT TEMPERATURES
COMPARED TO PREVIOUS NIGHTS...AND THEREFORE EXPECT MAINLY RAIN SOUTH
OF THE INTERSTATE 64 CORRIDOR...POSSIBLY BECOMING A WINTRY MIX
TOWARD SUNRISE MONDAY AS TEMPERATURES FALL NEAR FREEZING. ALONG AND
NORTH OF INTERSTATE 64...EXPECT POCKETS OF FREEZING RAIN OR SLEET TO
DEVELOP.

SOUTHWESTERLY WINDS WILL ALLOW FOR SIGNIFICANTLY WARMER TEMPERATURES
FOR MONDAY...WITH TEMPERATURES RANGING FROM THE MID 40S ACROSS
SOUTHEAST WEST VIRGINIA TO THE MID 50S ACROSS THE SOUTHSIDE. A COLD
FRONT WILL PASS ACROSS THE REGION DURING THE AFTERNOON...BRINGING A
NORTHWESTERLY WIND SHIFT AND AN INCREASE IN RAIN SHOWER ACTIVITY
ALONG THE BOUNDARY. SHOWERS WILL THEN DIMINISH IN COVERAGE DURING
THE EVENING IN THE DOWNSLOPE WINDFLOW...WITH A FEW SHOWERS LINGERING
ACROSS THE WESTERN SLOPES FROM WEST VIRGINIA INTO NORTHERN NORTH
CAROLINA.

HIGH PRESSURE WILL BUILD ACROSS THE SOUTHERN GREAT LAKES MONDAY
EVENING...EVENTUALLY CROSSING TO NEW ENGLAND...WHERE IT WILL THEN
BUILD SOUTHWARD ACROSS THE MID ATLANTIC BY TUESDAY MORNING. ANOTHER
DEEPER LOW PRESSURE SYSTEM WILL DEVELOP OVER THE PLAINS ON
TUESDAY...AND PUSH RAPIDLY NORTHEAST TOWARD THE GREAT LAKES. COLD
SURFACE TEMPERATURES PROVIDED BY HIGH PRESSURE COMBINED WITH THE
WARM AIR ALOFT AND DEEP MOISTURE AS PROVIDED BY THE LOW PRESSURE
SYSTEM TO OUR WEST WOULD MAKE FOR A CHANCE FOR FREEZING RAIN FROM
THE INTERSTATE 64 CORRIDOR...POSSIBLY AS FAR SOUTH AS THE NEW RIVER
VALLEY.

THE LOW PRESSURE SYSTEM WILL DRAG A COLD FRONT ACROSS OUR AREA ON
WEDNESDAY...POTENTIALLY BRINGING A ROUND OF LOCALLY HEAVY RAIN TO
THE MOUNTAINS. CHILLY ARCTIC AIR WILL BUILD INTO THE REGION BEHIND
THE COLD FRONT.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 1155 PM EST THURSDAY...

JUST A FEW SNOW SHOWERS AT BLF EARLY WITH FOG IN DAN THE MAIN
ISSUES. WILL ALSO SEE MVFR/VFR CIGS WITH SCATTERING OUT OF CIGS
EAST OF THE BLUE RIDGE BY MID MORNING.

ON FRIDAY...THE NORTHWEST FLOW WILL START MIXING TO THE SURFACE
SO THAT A PREVAILING 10 KT WIND WILL BE COMMON ACROSS THE
MOUNTAINS WITH 5 TO 10 KT COMMON ACROSS THE PIEDMONT.

FRIDAY AFTERNOON AND EVENING...MVFR CLOUDS ACROSS THE MOUNTAINS
WILL DECREASE IN COVERAGE.

VFR COLD HIGH PRESSURE WILL PREVAIL ON SATURDAY.

SUNDAY INTO MONDAY...OUR NEXT WEATHER SYSTEM WILL MOVE THROUGH THE
AREA. CONFIDENCE IS LOW CONCERNING THE EXACT DETAILS ON TIMING AND
PRECIP TYPE. HOWEVER...IT IS PROBABLE THAT THIS TIME PERIOD WILL
BE ONE WITH SUB-VFR CONDITIONS FOR MANY PARTS OF THE AREA.

ON THE HEELS OF THE SUNDAY/MONDAY SYSTEM WILL BE YET ANOTHER
POTENTIALLY POTENT SYSTEM THAT MAY IMPACT ALL OR PARTS OF THE
REGION LATE MONDAY NIGHT INTO AND THROUGH TUESDAY.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR NCZ001>006-
     018>020.
WV...NONE.

&&

$$
SYNOPSIS...DS
NEAR TERM...DS/WP
SHORT TERM...AMS
LONG TERM...NF
AVIATION...DS/NF/WP


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