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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 100511
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1211 AM EST WED FEB 10 2010

.SYNOPSIS...
A COMPLEX AREA OF LOW PRESSURE WITH ASSOCIATED FRONTAL BOUNDARIES
WILL MOVE EAST ACROSS THE REGION AND INTENSIFY ALONG THE MID
ATLANTIC COAST TONIGHT INTO WEDNESDAY. A STRONG ARCTIC COLD FRONT
WILL PUSH IN BEHIND THIS SYSTEM TONIGHT WITH VERY STRONG WINDS
AND COLD TEMPERATURES INTO THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
STILL GETTING A POTPOURRI OF PTYPES THIS EVENING. HAD A NICE BAND
OF HEAVIER SNOW COME THROUGH EARLIER THIS EVENING BRING UP TO 2
INCH AN HOUR RATES...BUT BAND MOVED THROUGH FAIRLY QUICKLY.
ATTM...RADAR IS SHOWING LINEAR TYPE BANDS OF PRECIP...WITH TEMP
PROFILES SUGGESTING ANYTHING FROM RAIN IN THE SOUTHEAST TO SNOW IN
THE NORTHWEST...AND MIXED IN BETWEEN. THE 18Z GFS SEEMED TO HANDLE
THE THERMAL PROFILE BETTER MATCHING UP WITH OUR 00Z
SOUNDING...ALTHOUGH COULD BE DRYING THINGS UP A LITTLE TOO FAST.

LOOKING UPSTREAM...STILL HAVE THE UPPER LOW TO CONTEND WITH THATS
SLIDING EAST TOWARD THE CENTRAL APPS THIS EVENING.
THEREFORE...KEPT ONGOING WINTER WX HEADLINES AS IS...ALTHOUGH DO
NOT FORESEE THE WARNING FOR THE NEW RIVER VALLEY BEING REACHED.
BUT UNTIL WE GET INTO THE UPSLOPE BEHIND THE UPPER SYSTEM WED
MORNING...AM RELUCTANT TO DOWNGRADE.

THE MAIN CHANGE TO THIS FORECAST WAS TO EXTEND OUR HIGH WIND
WARNING EAST TO COVER TO ENTIRE CWA. SOUNDINGS SUGGEST MOMENTUM
TRANSFER FROM STRONG LLJ AND TIGHT GRADIENT ON THE ORDER OF 50
KNOTS+. WITH A WET GROUND...SEE THE THREAT OF TREES DROPPING
FURTHER EAST. WILL KEEP THE FAR ERN CWA IN THE SAME TIME FRAME AS
MOST OF THE AREA RUNNING FROM MIDNIGHT TONIGHT TIL 5 AM THU...BUT
APPEARS BEST WINDS WILL BE A COUPLE HOURS AFTER THE FRONT MOVES
THROUGH LATE TONIGHT...AND THEN AGAIN IN THE AFTERNOON/EVENING
THURSDAY WITH THE UPPER LOW PASSING EAST.

VERY COLD AIR ALOFT WITH 500 MB TEMPERATURES BELOW -35 BY 12Z
WEDNESDAY. STRONG COLD AIR ADVECTION TONIGHT BRINGS 850 MB
TEMPERATURES DOWN TO THE -15 TO -18 RANGE BY 12Z WEDNESDAY.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
LOOKED AT THE CIPS WINTER WEATHER ANALOG TOOL...AND WAS ABLE TO
FIND A SIMILAR EVENT FROM DEC 25 2002. WHILE SIMILAR WITH THE
COASTAL LOW...I COULD NOT FIND ANY ANALOG WHICH SHOWED A CLOSED H5
LOW MOVING ACROSS THE REGION...WITH TROP HTS FALLING TO 300DM ABV
THE SURFACE PER THE GFS/NAM. THIS TROPOSPHERIC UNDULATION IS EVEN
MORE IMPORTANT CONSIDERING THE STRONG WINDS WHICH WILL BE SQUEEZED
BETWEEN THE TROPOPAUSE AND THE SURFACE. EVEN UNDERNEATH THE
INVERSION...WHICH DECENT LAPSE RATES DEVELOP AS CLDS BREAK AND
SOME SUNSHINE ALLOWS FURTHER MIXING. THERE SHOULD BE TWO
MAXIMA...ONE AS THE ARCTIC COLD FRONT CROSSES TONIGHT AND THEN
ANOTHER AS CLDS BREAK AND SUNSHINE TRIES TO PEEK THROUGH ALONG THE
DOWNSLOPE AREA. SEE HIGH WIND WARNG TEXT...HOWEVER THIS LOOKS TO
BE AN IMPRESSIVE ANOMALOUS EVENT...WHICH COULD PUT DOWN MANY TREES
AND CAUSE SOME STRUCTURAL DAMAGE...ESPECIALLY NEAR THE BLUE RIDGE
AND INTO NW NC. COULD IT PERHAPS RIVAL FEB 8 2008?

ALSO...SEVERAL INCHES OF UPSLOPE SNOW SHOULD ACCUMULATE THROUGH SE
WEST VA...SW VA AND INTO NW NC WEDNESDAY THROUGH THURSDAY. DID
CONSIDER PUTTING GRAYSON AND WYTHE INTO THE WINTER STORMS
WARNING...BUT SINCE AN ADVISORY WAS CURRENTLY IN AFFECT
THERE...DECIDED TO LET MID SHIFT CONSIDER THIS ONCE THE ADVISORY
CRITERIA PRECIP ENDS THIS EVENING. WOULD THINK THE HIGHEST PART OF
GRAYSON COUNT WOULDNT HAVE MUCH PROBLEMS GET WARNG CRITERIA SNOWS.
ALSO...THE WARNING MAY NEED TO BE EXTENDED INTO PART OF
THURSDAY...EVEN THOUGH THE MOISTURE IS VERY SHALLOW...H85 TEMPS
AOB -12C WILL SQUEEZE OUT ANY AVAILABLE MOISTURE. LAKE CONNECTION
WITH STRONG WINDS AND INVERSION TO NEAR 8 KFT AT TIMES SHOULD
ALLOW WRNG CRITERIA SNOWFALL TO BE REACHED.

&&

.LONG TERM /FRIDAY 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 /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.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...
VA...HIGH WIND WARNING UNTIL 5 AM EST THURSDAY FOR VAZ007-009>014-
     016>020-022>024-032>035-043>047-058-059.
     WINTER STORM WARNING UNTIL 5 AM EST WEDNESDAY FOR VAZ010-011-
     013-014-018>020-022>024-035.
     WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR VAZ012-
     016-017.
     HIGH WIND WARNING UNTIL 1 PM EST THURSDAY FOR VAZ015.
     WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ009-015.
     WINTER WEATHER ADVISORY UNTIL 5 AM EST WEDNESDAY FOR
     VAZ032>034-043>047-058-059.
     WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR VAZ007.
NC...HIGH WIND WARNING UNTIL 5 AM EST THURSDAY FOR NCZ003>006-019-
     020.
     HIGH WIND WARNING UNTIL 1 PM EST THURSDAY FOR NCZ001-002-018.
     WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR NCZ002.
     WINTER WEATHER ADVISORY UNTIL 5 AM EST WEDNESDAY FOR
     NCZ003>006-019-020.
     WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR NCZ001-018.
WV...HIGH WIND WARNING UNTIL 5 AM EST THURSDAY FOR WVZ042>045.
     WINTER STORM WARNING UNTIL 5 AM EST WEDNESDAY FOR WVZ044.
     WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR WVZ042-043-
     045.

&&

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