042
FXUS61 KRNK 091536
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1036 AM EST TUE FEB 9 2010
SYNOPSIS
A COMPLEX AREA OF LOW PRESSURE WITH ASSOCIATED FRONTAL BOUNDARIES
WILL MOVE EAST ACROSS THE REGION TODAY BEFORE INTENSIFYING ALONG THE
MID ATLANTIC COAST TONIGHT INTO WEDNESDAY. THIS WILL BRING PERIODS
OF SNOW THROUGH MIDDAY WITH A LIKELY CHANGEOVER TO MIXED
PRECIPITATION ACROSS PARTS OF THE AREA THIS AFTERNOON. A STRONG
ARCTIC COLD FRONT WILL PUSH IN BEHIND THIS SYSTEM WITH VERY STRONG
WINDS AND COLD TEMPERATURES WEDNESDAY INTO WEDNESDAY NIGHT.
NEAR TERM /UNTIL 6 PM THIS EVENING/
12Z NAM IS BRINGING SLIGHLY WARMER TEMPERATURES IN ALOFT THIS
AFTERNOON. SO AS THE PRECIPITATION FILLS BACK IN AND CONTINUES
UNTIL THE FRONT GOES THROUGH TONIGHT HAVE EXPANDED THE AREA WITH
SLEET AND A CHANCE OF FREEZING RAIN. THIS KEEPS THE HIGHEST SNOW
AND SLEET ACCUMULATIONS IN SOUTHEAST WEST VIRGINIA AND THE
ALLEGHANY HIGHLANDS.
ALSO RAISED HIGH TEMPERATURES A FEW DEGREES ON THE EDGE OF THE
CAD REGION. NO OTHER CHANGES AT THIS TIME TO ANY WINTER WEATHER
HEADLINES OR THE HIGH WIND WATCH.
SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/
LOW DEEPENS ON THE COAST OVERNIGHT AS THE 85H FRONT CROSSES THE
MOUNTAINS WITH STRONG COLD ADVECTION ENSUING. APPEARS DRY SLOT
SHOULD CUT OFF PRECIP ALL EXCEPT THE NORTH/NE DURING THE EVENING
BEFORE THE UPPER SYSTEM CROSSES AND UPSLOPE CRANKS UP LATE. LOCAL
WRF EVEN SHOWS A BAND OF SNOW MOVING INTO THE EAST AHEAD OF THIS
FEATURE SO BUMPED UP POPS SOME OUTSIDE OF THE NW NC FOOTHILLS.
BUFKIT ALSO SHOWS RH BECOME SHALLOW OVER THE EAST LATE WHERE COULD
BE MORE OF A FREEZING DRIZZLE THREAT. 85H JET REALLY CRANKS UP
OVERNIGHT WITH WARNING CRITERIA GUSTS POSSIBLE ON THE RIDGES LATE.
THIS WILL CREATE BLOWING SNOW PROBLEMS WITH LOW VSBYS LIKELY
ESPCLY WEST BY DAYBREAK. SINCE MAY HAVE PROBLEMS WITH LINGERING
ICE IN THE EAST WILL ISSUE A HIGH WIND WATCH FOR THE ENTIRE CWA
STARTING AT MIDNIGHT. THIS ALSO SUPPORTED BY LOCAL RESEARCH WHICH
SHOWS POTENTIAL FOR DAMAGING WINDS TO GO EAST OF THE MOUNTAINS
WITH A DEEPENING COASTAL LOW. TEMPS WILL CRASH WITH THE ARRIVAL
OF THE 85H SURGE WITH MID/UPPER TEENS LIKELY WEST FOR LOWS BUT
LIKELY HELD UP SOME OUT EAST WHERE THE COLDEST AIR WONT ARRIVE
UNTIL JUST BEFORE DAWN.
AT THE SURFACE WEDNESDAY...THE LOW PRESSURE SYSTEM WILL BE
PUSHING NORTHEAST OFFSHORE AND DEEPENING RAPIDLY. WHILE THE UPPER
LOW WILL BE CROSSING THE COUNTY WARNING AREA. THIS WILL LEAVE THE
FORECAST AREA IN AN UPSLOPE SNOW REGIME ONCE AGAIN AS WRAP AROUND
MOISTURE ON THE BACKSIDE OF THE LOW REMAINS IN THE WEST. AS A
RESULT...UPSLOPE SNOW SHOWERS WILL OCCUR IN SOUTHEAST WEST
VIRGINIA SOUTH INTO THE NORTHERN NORTH CAROLINA MOUNTAINS
WEDNESDAY. THERE WILL BE A GOOD TRAJECTORY OFF OF LAKE MICHIGAN ON
WEDNESDAY NIGHT...ESPECIALLY IN SOUTHEAST WEST VIRGINIA. THESE
UPSLOPE SNOW SHOWERS WILL CONTINUE THROUGH THURSDAY NIGHT AND WILL
TAPER OFF FROM SOUTH TO NORTH. HPC GUIDANCE SUGGESTS A POTENTIAL
FOR UP TO 6 INCHES ADDITIONAL SNOW ACCUMULATION THROUGH THIS TIME
PERIOD.
STRONG COLD AIR WILL CONTINUE TO ADVECT INTO THE REGION IN THE WAKE
OF THE COLD FRONT. 85H TEMPERATURES WILL DROP INTO THE -16 TO -12 C
RANGE. A STRONG LOW LEVEL JET WILL DEVELOP WITH 85H WINDS INCREASING
INTO THE 50 TO 60 KNOTS RANGE EARLY WEDNESDAY MORNING. THESE REASONS
ALONG WITH RAPID PRESSURE RISES OF 4 TO 7MB...WINDS COULD POSSIBLY
REACH INTO WARNING CRITERIA. AT THIS TIME...HAVE HOISTED A HIGH WIND
WATCH FOR THE ENTIRE COUNTY WARNING AREA. HOWEVER...BELIEVE THE
HIGHEST WIND GUSTS WILL IMPACT THE MOUNTAINOUS AREAS AND ESPECIALLY
ALONG THE RIDGES.
WIND CHILLS COULD ALSO REACH ADVISORY CRITERIA WEDNESDAY NIGHT BUT
WILL CONTINUE TO MENTION IN THE HWO FOR NOW.
THURSDAY AND THURSDAY NIGHT...THE LOW WILL BE FURTHER OUT OVER THE
ATLANTIC WHILE THE AREA WILL BE IN TRANSITION AS A SURFACE RIDGE
TRIES TO PUSH INTO THE FORECAST AREA. UPSLOPE SNOW SHOWERS WILL
DIMINISH BY THE EVENING THURSDAY.
TEMPERATURES WILL REMAIN BELOW SEASONAL NORMS.
LONG TERM /FRIDAY THROUGH MONDAY/
HIGH PRESSURE BUILDS INTO THE AREA ON FRIDAY ALL WHILE A
DEEPENING AREA OF LOW PRESSURE SWINGS SOUTH OF THE AREA THROUGH
THE GULF COAST STATES. PRECIPITATION FROM THAT SYSTEM IS EXPECTED
TO REMAIN SOUTH OF THE AREA.
NORTHWEST FLOW INCREASES AGAIN OVER THE WEEKEND AS ANOTHER SHORTWAVE
TROUGH SPINS OUT OF THE GREAT LAKES AND THROUGH OUR REGION. TIMING
OF THIS FEATURE VARIES AMONG THE MODELS...BUT THE GENERAL CONSENSUS
IS A RETURN OF UPSLOPE SNOW SHOWERS FROM SE WV SOUTH INTO THE
NORTHERN MOUNTAINS OF NORTH CAROLINA SATURDAY THROUGH MONDAY.
FOR TEMPERATURES DURING THE PERIOD HAVE FAVORED NUMBERS IN LINE WITH
THE LATEST HPC GUIDANCE.
AVIATION /16Z TUESDAY THROUGH SATURDAY/
RECENT RADAR OBSERVATIONS SHOW LIGHT TO MODERATE BANDS OF SNOW
ASSOCIATED WITH THE LOW PRESSURE SYSTEM QUICKLY SPREADING EAST
ACROSS THE AREA. ALL TAF SITES WILL CONTINUE TO BE IMPACTED
THROUGHOUT THE TAF PERIOD. EXPECT BANDS OF SNOW TO CONTINUE
THROUGH THE MORNING HOURS THEN CHANGING OVER TO A SLEET/SNOW
MIXTURE IN THE AFTERNOON. AT THIS TIME...KDAN REMAINS VFR BUT
EXPECT THE CONDITIONS TO DETERIORATE LATER THIS MORNING INTO EARLY
AFTERNOON. VISIBILITIES WILL REMAIN REDUCED TO MVFR OR LOWER
DURING THESE SNOW BANDS. SOME BRIEF BREAKS IN PRECIPITATION IS
EXPECTED ESPECIALLY EARLY THIS MORNING...THEN THE HEAVIER
PRECIPITATION SHOULD MOVE IN BY EARLY AFTERNOON.
A LOW LEVEL WIND SHEAR ISSUE IS NOT OUT OF THE QUESTION AS WINDS
IN THE 1-3 KFT RANGE WILL BE INCREASING FROM THE SOUTH. HAVE LEFT
OUT OF THE TAFS FOR NOW AS IT WILL BE LATER THIS AFTERNOON INTO
THE EVENING.
POOR FLIGHT CONDITIONS WILL CONTINUE INTO EARLY WEDNESDAY OUT
EAST...WITH FLOW BEHIND THE FRONT KICKING UP SEVERAL NOTCHES WITH
WEST TO NORTHWEST WINDS ACCELERATING TO 20 TO 30 KNOTS...WITH
GUSTS TO 40 KNOTS POSSIBLE MAINLY OVER ROANOKE.
UPSLOPE SNOW SHOWERS AND CLOUDS WILL REMAIN INTO THURSDAY OVER BLF/LWB.
SHOULD SEE SOME IMPROVEMENT BY FRIDAY IN SE WV AS HIGH PRESSURE
MOVES IN.
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...WINTER STORM WARNING UNTIL 5 AM EST WEDNESDAY FOR VAZ010-011-
013-014-018>020-022>024-035.
HIGH WIND WATCH FROM LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT
FOR VAZ007-009>020-022>024-032>035-043>047-058-059.
WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR VAZ012-
016-017.
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 WATCH FROM LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT
FOR NCZ001>006-018>020.
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...WINTER STORM WARNING UNTIL 5 AM EST WEDNESDAY FOR WVZ044.
HIGH WIND WATCH FROM LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT
FOR WVZ042>045.
WINTER STORM WARNING UNTIL 6 AM EST THURSDAY FOR WVZ042-043-
045.
SYNOPSIS...AMS/JH
NEAR TERM...AMS
SHORT TERM...JH/REB
LONG TERM...DS
AVIATION...REB
EQUIPMENT...JH
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