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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 100546
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1246 AM EST WED FEB 10 2010

.SYNOPSIS...
ARCTIC FRONT BLOWS THROUGH THIS EVENING. MUCH COLDER AND BRISK WITH
SNOW SHOWERS THROUGH WEDNESDAY NIGHT. UPSLOPE SNOW SHOWERS LINGER
INTO THURSDAY FOR MOUNTAINS. COLD PATTERN CONTINUES INTO NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SNOW SHOWERS EXPENDING IN AREA COVERAGE AND INTENSITY IN WAKE OF
ARCTIC FRONT BLOWING THROUGH THE AREA.  THE SNOW SHOWERS WERE
FOCUSED IN TWO AREAS ON ACCOUNT OF A DOUBLE FRONT STRUCTURE...THE
SECOND BEHIND WHICH THE ARCTIC AIR REALLY SURGES IN.  THEE WILL
LIKELY BE A LULL IN THE PRECIPITATION SOMETIME AFTER THE SECOND
FRONT...ACTUALLY DUE THROUGH AS WE GO THROUGH THE MIDNIGHT
HOUR...BEFORE THE UPSLOPE MACHINE CRANKS UP ON WED.  THE UPPER LEVEL
LOW AND ASSOCIATED CORE OF THE ARCTIC AIR MASS CROSSES THE AREA
FIRST THING WEDNESDAY MORNING...WITH ITS ASSOCIATED TROPOPAUSE FOLD
IN THE NAM ALMOST ALL THE WAY DOWN TO ABOUT 800MB!  IT APPEARS GOOD
SNOWS WILL SET UP WITH AND AFTER THAT...THE LATTER IN DEEP ALIGNED
WNW FLOW WITH TRAJECTORY RIGHT OFF LAKE MICHIGAN AIMED RIGHT AT THE
SOUTHERN HALF OF THE FORECAST AREA.  PRECIPITATION PATTERN WILL
LIKELY EVOLVE INTO A MORE CLASSIC UPSLOPE CONFIGURATION WED
AFTERNOON.

PUT LAV TEMPERATURES IN INITIALLY BUT...WITH ITS RATHER LAZY
PATTERN...THOUGH BETTER OF IT GIVEN THE ARCTIC POOL THAT LIKELY
EXHIBITS AT LEAST 2 SD BELOW NORMAL...NOT GOOD FOR ANY KIND OF MOS
PRODUCT.  AVERAGING IN THE BL030 TEMPERATURES FROM THE NAM12 SEEMED
TO PRODUCE A MUCH BETTER FIT INTO WED GIVEN TEMPERATURES UPSTREAM.

ADDED A WIND CHILL ADVISORY FOR THE NORTHERN MOUNTAINS GIVEN THE
ARCTIC POOL ARRIVING FIRST THING WED MORNING.  ONGOING WINTER STORM
WARNING WILL CONTINUE THROUGH THE NEAR TERM PERIOD...THOUGH WESTERN
PORTION OF THE WARNING WILL END UP WITH LESS SNOW COMPARED WITH THE
EASTERN PORTION /WV MOUNTAINS/. ALSO...AREA THAT GOT ESPECIALLY WARM
WEDGED WITH RAIN TUESDAY IN THE LOWLANDS...WILL KEEP THE ADVISORY
WITH LESS TOTAL SNOW WHEN INCLUDING WHAT HAPPENED EARLIER TODAY.
ALSO MAINTAINED WIND ADVISORY IN THE MOUNTAINS.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
THE COMPLEX WEATHER SYSTEM CONTINUES TO AFFECT OUR AREA THIS
PERIOD. MODELS ARE IN VERY GOOD AGREEMENT ON THE PROGRESSIVE VERY
STRONG AND COLD UPPER LOW DRIVING AN ARCTIC FRONT ACROSS THE AREA
TONIGHT...FOLLOWED BY A UNIQUE WARM ADVECTION SNOW EVENT LATE
TONIGHT AND WEDNESDAY.

FIRST...A PSEUDO COLD FRONT MOVES ACROSS THIS EVENING...AHEAD OF A
SOUTHERN STREAM UPPER TROUGH THAT LIFTED OUT AHEAD OF THIS UPPER
LOW...AND EFFECTIVELY ENDING MOST OF OUR PRECIPITATION THIS EVENING.
MOST OF THE PRECIP WAS LIGHT AND MAINLY IN THE FORM OF RAIN THIS
AFTERNOON...EXCEPT OVER PARTS OF SOUTHEAST OHIO AND HIGHER WEST
VIRGINIA MOUNTAIN ELEVATIONS. MOST TEMPERATURES WILL REMAIN CLOSE TO
OR JUST ABOVE FREEZING BEFORE THE ARCTIC FRONT PASSES A BIT LATER
TONIGHT.

THERE WILL BE A RELATIVE LULL IN THE PRECIP EARLY TONIGHT...UNTIL
DEEP MOIST WRAPAROUND NORTHWEST FLOW WITH THE UPPER LOW OVERSPREADS
OUR AREA LATER TONIGHT AND WEDNESDAY. THIS IS A UNIQUE
PATTERN WHERE MOST OF OUR PRECIP LATER TONIGHT AND WEDNESDAY WILL BE
WARM ADVECTION SNOW...WITH ATLANTIC MARITIME AIR BEING DRAWN ALL
THE WAY AROUND THIS UPPER LOW. THIS SCENARIO WILL BRING ABOUT A MORE
WIDESPREAD SNOW IN THIS WARM ADVECTION NORTHWEST FLOW. THIS MAY
SOMEWHAT LIMIT LOCALIZED HEAVY BANDS OF SNOW THAT WE COMMONLY FIND
IN COLD ADVECTION NORTHWEST UPSLOPE FLOW AND PLUMES OFF THE LAKES.
NEVERTHELESS...SIGNIFICANT ACCUMULATIONS OF SNOW ARE EXPECTED ACROSS
THE AREA THROUGH WEDNESDAY...AND INTO WEDNESDAY IN THE NORTHERN
MOUNTAINS. DESPITE LACK OF STRONG COLD ADVECTION...THE MOUNTAINS
WILL STILL SEE ENHANCED UPSLOPE SNOWS WITH IDEAL NORTHWEST FLOW.
GUSTY WINDS WILL ALSO CAUSE SOME BLOWING AND DRIFTING OF THE
SNOW...ESPECIALLY IN THE MOUNTAINS WHERE WIND ADVISORIES WILL BE IN
EFFECT LATER TONIGHT AND WEDNESDAY. THUS...WINTER STORM WARNINGS AND
ADVISORIES WILL ALSO REMAIN IN EFFECT. HOWEVER...NO WIND CHILL
ADVISORY...AS CRITERIA NOT MET OUTSIDE THE HIGHEST ELEVATIONS.

TEMPS WILL BE TRICKY...WITH THE WARM ADVECTION PATTERN WEDNESDAY. SO
AFTER TEMPS TAKE A FALL BEHIND THE ARCTIC FRONT TONIGHT...WE LOOK
FOR SOME TEMPERATURE RECOVERY WEDNESDAY...BUT WILL REMAIN BELOW
FREEZING.  GOING ON THE LOWE SIDE OF GUIDANCE.

HIGH PRESSURE BUILDS IN WEDNESDAY NIGHT AND THURSDAY...WITH SNOW AND
SNOW SHOWERS DIMINISHING...LEADING TO QUITE COLD TEMPERATURES ONCE
AGAIN.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
BASED ON 850 MB TEMPERATURES AND LOW LEVEL MOISTURE...WILL LINGER A
FEW SNOW SHOWERS IN THE NORTHERN MOUNTAINS FOR FRIDAY MORNING.
MODELS SHOW THE COLD PATTERN HOLDING THROUGH THE WEEKEND AND INTO
NEXT WEEK. WHILE THERE IS GOOD AGREEMENT ON THE GENERAL COLD
PATTERN...CONFIDENCE IN THE DETAILS AND TIMING OF PRECIPITATION
IMPULSES IS LOW.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
STRONG SNOW SQUALL LINE HAS JUST PASSED THROUGH CRW WITH NEAR ZERO
VISIBILITY SNOW AND WIND GUSTS OUT OF THE WEST TO 40KTS. BEHIND
THIS LINE...CALMER CONDITIONS PREVAIL...WITH VISIBILITIES IMPROVING
IN THE BREAK FROM SNOW. WINDS WILL STAY UP HOWEVER IN THE WAKE OF
THIS SQUALL LINE...LASTING THROUGH THE DURATION OF THE TAF.
CEILINGS MAY BRIEFLY GO IFR IN THE DRY SLOT...BUT OVERALL WILL SEE
A DOMINANT LOW END MVFR DECK THROUGH WEDNESDAY.

SNOW SHOWERS IN NORTHWESTERLY FLOW COMMENCE GENERALLY AFTER 12Z
WEDNESDAY...AND WILL KEEP THE VISIBILITIES IFR. MAY NEED TEMP
GROUPS BEYOND 12Z ONCE THE PREVAILED TRACK OF THE MOISTURE PLUMES
SET UP. THIS COULD FAVOR THE WESTERN ZONES OF THE CWA...BUT WILL
TREAT ALL SITES AS EQUAL FOR NOW.

AFTER 06Z THURSDAY...
INTERMITTENT IFR OR WORSE CONDITIONS EXPECTED IN BANDS OF SNOW
SHOWERS THROUGH WEDNESDAY NIGHT...ESPECIALLY IN THE
MOUNTAINS...WHERE IT MAY LAST WELL INTO THURSDAY MORNING.
-- End Changed Discussion --

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
WV...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR WVZ005>007-
     009>011-017>020-027>032-035>040-046-047.
     WIND ADVISORY UNTIL 4 AM EST THURSDAY FOR WVZ033>038-046-047.
     WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 AM EST
     THURSDAY FOR WVZ038-046-047.
     WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR WVZ008-
     013>016-024>026-033-034.
OH...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR OHZ066-067-
     075-076-083>087.
KY...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR KYZ101>103-
     105.
VA...WIND ADVISORY UNTIL 4 AM EST THURSDAY FOR VAZ003-004.
     WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR VAZ003-004.
-- End Changed Discussion --

&&

$$
SYNOPSIS...TRM/MDP/JMV/RPY
NEAR TERM...TRM/MDP
SHORT TERM...JMV
LONG TERM...RPY
AVIATION...26