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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 100831
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
331 AM EST WED FEB 10 2010

.SYNOPSIS...
-- Changed Discussion --
LOW PRESSURE WILL INTENSIFY OFF THE MID ATLANTIC COAST TODAY AND
THEN SLOWLY LIFT NORTHEAST AND AWAY FROM THE AREA LATER TONIGHT. A
STRONG ARCTIC COLD FRONT TRAILING THIS SYSTEM WILL USHER IN VERY
STRONG WINDS AND COLD TEMPERATURES INTO THURSDAY. THIS IN
COMBINATION WITH RESIDUAL MOISTURE AND NORTHWEST FLOW WILL ALSO
RESULT IN WIDESPREAD SNOW SHOWERS ACROSS THE MOUNTAINS.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
ARCTIC FRONT NOW CROSSING THE BLUE RIDGE WILL CONTINUE TO WORK
EAST BRINGING A SUDDEN INCREASE IN WINDS ALONG WITH FALLING TEMPS
AND A QUICK SHOT OF HEAVIER SNOWFALL THRU DAYBREAK. THUS EXTENDING
THE GOING ADVISORY IN SPOTS THRU NOON TO COVER THIS AND QUICK
FREEZING OF MOISTURE WHERE -SN PERSIST ALONG 460 EARLY ON. THEN
AS THE COASTAL STARTS TO DEEPEN LATER THIS MORNING...GOOD
TRAJECTORY OF UPSLOPE SNOWFALL SHOULD CRANK INTO GEAR AND PERSIST
INTO TONIGHT. WITH MOISTURE DEPTH GOOD AND UNIFORM NW FLOW...WITH
SPEED SHEAR WITH HEIGHT THRU A LAYER OF DEVELOPING
INSTABILITY...EXPECT HEAVIER SNOW SQUALLS TO BECOME QUITE
WIDESPREAD BY AFTERNOON ACROSS THE WEST. THINKING UP TO A FOOT
ACROSS WESTERN GREENBRIER THRU TONIGHT WITH WARNING CRITERIA ALL
ALONG THE WESTERN SLOPES WHERE WILL ADD A COUPLE MORE COUNTIES TO
THE WARNING. STEEP LAPSES UNDER THE COLD POOL SHOULD ALSO ALLOW
ACCUMULATING SNOW TO WORK FARTHER EAST SO INCLUDING ANOTHER LAYER
OF COUNTIES ACROSS THE WEST IN AN ADVISORY THRU EARLY THU. WARNING
MAY NEED TO GO LONGER INTO THU BUT DEEP RH ON THE WANE BY THEN SO
WILL HOLD OFF FOR NOW. ALSO CONSIDERED A BLIZZARD WARNING FOR
PARTS OF THE WESTERN SLOPES GIVEN STRONG WINDS AND BLOWING SNOW
ALTHO THINK VSBYS MAY ONLY DROP BELOW A 1/4 MILE AT TIMES SO HELD
OFF. OTRW CAT POPS WESTERN SLOPES RANGING TO CHANCE JUST EAST OF
THE BLUE RIDGE AND LITTLE ACROSS THE PIEDMONT AFTER EARLY THIS
MORNING. FALLING TEMPS IN ORDER UNDER THE PASSING CORE OF -18C 85H
COLD POOL THIS MORNING WITH ONLY A SLIGHT REBOUND...BUT BELOW MOS
THIS AFTERNOON.

BIGGEST ISSUE IS THE THREAT FOR WIDESPREAD WIND DAMAGE ESPCLY
LATER THIS AFTERNOON AS WE GET A FEW BREAKS AND MIXING ENHANCES
UNDER A LOWERING INVERSION. LATEST FCST RAOBS SHOW POTENTIAL FOR
THE HIGHER RIDGES TO SEE GUSTS IN EXCESS OF 70-75 MPH NW NC AND
60+ BLUE RIDGE. THINGS MAY NOT BE QUITE IN SYNC AS THE FEB 2008
EVENT REGARDING COLD ADVECTION...SUBSIDENCE AND JET DYNAMICS BUT
CLOSE ENOUGH ESPCLY IF LAPSES COME IN LINE WHEN THE 85H JET IS
STRONGEST LATER ON TO PRODUCE A QUITE DAMAGING EVENT. STRONGEST WINDS
WILL LIKELY PERSIST THRU MIDNIGHT AND THEN SLACKEN SOME BUT STILL
WARNING CRITERIA ON THE RIDGES THRU THU MORNING. OTRW TYPICAL
BREAK IN CLOUDS IN NW FLOW REGIME OVERNIGHT WITH CLOUDS/SNOW
SHOWERS WEST AND CLEARING EAST. TEMPS LIKELY TO BE STEADY OR RISE
SOME GIVEN MIXING AND STEADY STATE 85H VALUES.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
UPSLOPE SNOW SHOWERS WILL CONTINUE THROUGH THURSDAY NIGHT ALONG THE
FAVORABLE WESTERN UPSLOPE AREAS IN SOUTHEAST WEST VIRGINIA SOUTH
THROUGH THE MOUNTAIN EMPIRE AND THE NORTHERN MOUNTAINS OF NORTH
CAROLINA. IT WILL BEGIN TAPERING OFF FROM SOUTH TO NORTH THROUGH THE
NIGHT THURSDAY. AN ADDITIONAL 2 INCHES OR LESS COULD ACCUMULATE
BEFORE ALL IS SAID AND DONE.

WINDS WILL SUBSIDE THROUGH LATE EVENING THURSDAY AS THE LOW LEVEL
JET DIMINISHES.

HIGH PRESSURE NOSES INTO THE AREA FROM THE WEST FRIDAY ENDING THE
UPSLOPE SNOW SHOWERS.

TEMPERATURES WILL REMAIN BELOW SEASONAL NORMS.
-- End Changed Discussion --

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
SATURDAY...AN AREA OF LOW PRESSURE WILL MOVE THROUGH THE GULF COAST
STATES WHERE ITS ASSOCIATED ENERGY AND PRECIPITATION WILL OCCUR.
ONLY THE UNPREFERRED GEM SOLUTION CONTINUES TO KEEP SOME LIGHT
PRECIPITATION ASSOCIATED WITH THE NORTHERN EXPANSE OF PRECIPITATION
ON THE NORTH SIDE OF THE LOW OVER OUR AREA. WE WILL CONTINUE WITH A
FORECAST THAT DOES NOT HAVE THIS SYSTEM IMPACT OUR REGION.

WHAT WILL HAVE A CHANCE TO IMPACT THE WEATHER FOR AT LEAST A
PORTION OF THE AREA...WILL BE A RETURN TO NORTHWEST UPSLOPE FLOW
INTO THE SE WV MOUNTAINS BY SATURDAY IN ADVANCE OF AN APPROACHING
SHORTWAVE SWINGING SOUTH OUT OF THE GREAT LAKES. GUIDANCE VARIES ON
THE TIMING AND MOISTURE CONTENT OF THIS SYSTEM. HAVE FAVORED THE
GUIDANCE OFFERED BY HPC THAT SUGGESTS THE BULK OF THE ENERGY AND
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL BRING SCATTERED
PRECIPITATION...RAIN OR SNOW SHOWERS DEPENDING UP THE LOCAL
TEMPERATURE...TO A GREATER EXPANSE OF THE REGION ON SUNDAY. JUST
AHEAD...AND ESPECIALLY BEHIND THIS SYSTEM...A RETURN OF SNOW SHOWERS
IN THE SE WV MOUNTAINS SOUTH INTO THE NORTHERN MOUNTAINS OF NW NC IS
EXPECTED WITH A TREND TOWARDS DECREASING COVERAGE ON TUESDAY. HAVE
ALSO FAVORED TEMPERATURES IN LINE WITH GUIDANCE FROM HPC

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
ON FRIDAY...HIGH PRESSURE MOVES OVERHEAD AND BRINGS AN END TO THE
UPSLOPE SNOW SHOWERS IN THE WEST VIRGINIA MOUNTAINS. FRIDAY INTO
SATURDAY...AN AREA OF LOW PRESSURE WILL MOVE THROUGH THE GULF COAST
STATES WHERE ITS ASSOCIATED ENERGY AND PRECIPITATION WILL OCCUR.
ONLY THE UNPREFERRED GEM SOLUTION CONTINUES TO KEEP SOME LIGHT
PRECIPITATION ASSOCIATED WITH THE NORTHERN EXPANSE OF PRECIPITATION
ON THE NORTH SIDE OF THE LOW OVER OUR AREA. WE WILL CONTINUE WITH A
FORECAST THAT DOES NOT HAVE THIS SYSTEM IMPACT OUR REGION.

WHAT WILL HAVE A CHANCE TO IMPACT THE WEATHER FOR AT LEAST A
PORTION OF THE AREA...WILL BE A RETURN TO NORTHWEST UPSLOPE FLOW
INTO THE SE WV MOUNTAINS BY SATURDAY IN ADVANCE OF AN APPROACHING
SHORTWAVE SWINGING SOUTH OUT OF THE GREAT LAKES. GUIDANCE VARIES ON
THE TIMING AND MOISTURE CONTENT OF THIS SYSTEM. HAVE FAVORED THE
GUIDANCE OFFERED BY HPC THAT SUGGESTS THE BULK OF THE ENERGY AND
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL BRING SCATTERED
PRECIPITATION...RAIN OR SNOW SHOWERS DEPENDING UP THE LOCAL
TEMPERATURE...TO A GREATER EXPANSE OF THE REGION ON SUNDAY. JUST
AHEAD...AND ESPECIALLY BEHIND THIS SYSTEM...A RETURN OF SNOW SHOWERS
IN THE SE WV MOUNTAINS SOUTH INTO THE NORTHERN MOUNTAINS OF NW NC IS
EXPECTED WITH A TREND TOWARDS DECREASING COVERAGE ON TUESDAY. HAVE
ALSO FAVORED TEMPERATURES IN LINE WITH GUIDANCE FROM HPC.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
FRONT NOW MOVING ACROSS THE NEW RIVER VALLEY...AND WINDS SHOULD BE
PICKING UP AT ROANOKE BY 09Z. ALREADY SEEING GUSTS TO 25KTS AT
BLF.

EXPECTING A PERIOD OF FREEZING DRIZZLE AND SNOW EARLY AT ROANOKE
AND LYH THEN WINDS PICK UP CLEARING THE PRECIP OUT BEHIND THE
FRONT. LOOKING AT IMPROVEMENTS TO MVFR/VFR OUT EAST BY 12-17Z.

THE MAIN IMPACT IN THE TAFS WILL BE THE STRONG NW FLOW BEHIND
THE FRONT. A PROLONGED PERIOD OF NW WINDS OF 15 TO 30 KNOTS WITH
GUSTS AS HIGH AS 45 TO 55 KNOTS IS POSSIBLE AT TIMES WEDNESDAY
INTO WEDNESDAY NIGHT. SEVERE TURBULENCE WILL BE THE RULE.

MVFR TO IFR CONDITIONS AND SNOW SHOWERS WILL OCCUR IN
BLF/LWB...ALONG WITH BLOWING SNOW.

SHOULD SEE SOME IMPROVEMENT BY FRIDAY IN SE WV AS HIGH PRESSURE
MOVES IN.

A CLIPPER SYSTEM ARRIVES SUNDAY AND COULD BRING SOME LOWER CIGS
INTO BLF/LWB AND EVEN ROANOKE. NW FLOW BEHIND THIS WILL KEEP SOME
POTENTIAL MVFR CIGS OR LOWER IN BLF/LWB EARLY NEXT WEEK WITH
MAINLY VFR ELSEWHERE.

&&

.EQUIPMENT...
MALFUNCTION OF THE NEW CEILOMETERS AT LYH...AND BLF HAS BEEN
REPORTED BY NATIONAL WEATHER SERVICE EASTERN REGION. THE CEILING
AT BLF IS NOW BEING REPORTED...AND APPEARS IN LINE WITH
SURROUNDING OBSERVATIONS. IF A DISCREPANCY IS NOTED...THE
CEILOMETER WILL NEED TO BE LOGGED OUT AGAIN. THE CEILING AT LYH
MAY NOT BE REPRESENTATIVE DURING THE OVERNIGHT HOURS WHEN THE
CONTROL TOWER IS CLOSED.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
VA...HIGH WIND WARNING UNTIL 5 AM EST THURSDAY FOR VAZ007-009>014-
     016>020-022>024-032>035-043>047-058-059.
     WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VAZ013-014-
     016>019-022>024-033>035-045>047.
     WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ010>012-
     020.
     HIGH WIND WARNING UNTIL 1 PM EST THURSDAY FOR VAZ015.
     WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR VAZ007-009-
     015.
NC...HIGH WIND WARNING UNTIL 5 AM EST THURSDAY FOR NCZ003>006-019-
     020.
     WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR NCZ002.
     HIGH WIND WARNING UNTIL 1 PM EST THURSDAY FOR NCZ001-002-018.
     WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR NCZ001-018.
WV...HIGH WIND WARNING UNTIL 5 AM EST THURSDAY FOR WVZ042>045.
     WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR WVZ044.
     WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR WVZ042-043-
     045.
-- End Changed Discussion --

&&

$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...REB
LONG TERM...DS
AVIATION...AMS/WP
EQUIPMENT...