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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 092352
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
652 PM EST TUE FEB 9 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/...
ANOTHER BAND OF PRECIPITATION INDICATED IN THE RELATIVE HUMIDITY
GUIDANCE ALONG AND JUST AHEAD OF THE UPPER LOW WHICH WILL TRACK
ACROSS THE NORTHERN COUNTY WARNING AREA BETWEEN 00-06Z.

DRY SLOT AT MID AND UPPER LEVELS COMES IN AFTER 00Z. MAY ADDED MORE
FREEZING DRIZZLE IN AHEAD OF THE FRONT. BETWEEN 06-12Z DEEP MOISTURE
FILLS IN OVER THE UPSLOPE REGIONS. THERE IS ENOUGH DRYING EVEN AT
LOW LEVEL AFTER 06Z IN THE SOUTHEAST TO START CLEARING OUT THE CLOUD
COVER. THIS ALSO LIMITS ICE CRYSTAL GROWTH BRIEFLY UNTIL THE FRONT
GOES THROUGH SO HAVE FREEZING DRIZZLE IN FOR TONIGHT.

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.

AT 00Z THE COLD FRONT WILL BE APPROACHING THE WESTERN EDGE OF THE
FORECAST AREA AND BY 06Z THE FRONT WILL BE WELL EAST OF THE COUNTY
WARNING AREA. PRESSURE RISES...COLD AIR ADVECTION AND THE DEEPENING
COASTAL LOW OVERNIGHT WILL RESULT IN VERY STRONG WINDS SO WILL
UPGRADE TO A HIGH WIND WARNING.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
THE HIGH WIND WATCH WAS UPGRADED TO A HIGH WIND WARNING FOR NEARLY
TO ENTIRE CWA. 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 /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
KEEPING MAINLY SNOW IN THE TAFS THIS EVENING OUT EAST WITH IFR TO
LIFR CIGS ADN VSBYS. LYH COULD SEE A ONE HOUR PERIOD OF SNOW WITH
LESS THAN 1SM VSBY BETWEEN 00Z-01Z...AS RADAR SHOWING DECENT
BRIGHT BANDING MOVING INTO THE SMITH MTN LAKE AREA ATTM.

THE COLD FRONT IS NOW JUST WEST OF BLF...AND WILL BE PASSING BLF
BY 03Z. THERE IS A LAG IN THE STRONGER WINDS UNTIL YOU GET BACK
INTO WRN KY...SO AM HOLDING ON THE HIGHER WINDS UNTIL ABOUT 09Z AT
BLF...BUT THERE WILL BE SOME GUST POST FRONTAL.

THE FRONT WILL PASS ACROSS LWB AT ABOUT THE SAME TIME...REACHING
ROANOKE BY 07Z/LYH 10Z...DAN/09-10Z. UNTIL THE FRONT MOVES ACROSS
IN THE EAST...CIGS WILL STAY DOWN. CANNOT RULE OUT SOME PATCHY
FREEZING DRIZZLE...BUT LEFT THEM OUT OF THE TAFS AS THE COLDER
ARRIVES BEHIND THE FRONT SHOWING MORE OF --SN SCENARIO FOR ROANOKE
AND EAST.

THE MAIN IMPACT IN THE TAFS BEYOND TONIGHT WILL BE THE STRONG NW
FLOW BEHIND THIS SYSTEM. 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.

CIGS WILL IMPROVE TO VFR BY LATE MORNING/MIDDAY IN THE ROANOKE AND
POINTS EAST AREA...BUT 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 FROM MIDNIGHT TONIGHT TO 5 AM EST THURSDAY
     FOR VAZ007-009>014-016>020-022>024-032>035-043>047.
     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 FROM MIDNIGHT TONIGHT TO 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.
     HIGH WIND WATCH FROM MIDNIGHT EST TONIGHT THROUGH LATE
     WEDNESDAY NIGHT FOR VAZ058-059.
NC...HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST THURSDAY
     FOR NCZ003-004-019-020.
     HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 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.
     HIGH WIND WATCH FROM MIDNIGHT EST TONIGHT THROUGH LATE
     WEDNESDAY NIGHT FOR NCZ005-006.
WV...HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 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
SHORT TERM...KM
LONG TERM...DS
AVIATION...AMS/WP
EQUIPMENT...