FXUS61 KRLX 081755
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1255 PM EST TUE DEC 8 2009
.SYNOPSIS...
PRECIPITATION ASSOCIATED WITH WARM FRONT THIS AFTERNOON AND TONIGHT.
DEEPENING LOW LIFTS NORTHEAST THROUGH GREAT LAKES WEDNESDAY.PUSHING
COLD FRONT THROUGH. HIGH PRESSURE FRIDAY. LOW PRESSURE THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED WIND ADVISORY TO HIGH WIND WARNING AND ISSUED WIND
ADVISORY FOR REST OF CWA. MODELS AND BUFKIT SOUNDINGS SUPPORT
SUSTAIND WINDS 15 TO 25KTS AND WIND GUSTS TO 50 IN ADVISORY AREA
AND UP TO 60KTS IN HIGHER ELEVATIONS OF THE EASTERN MOUNTAINS DOWN
TO SW VA. KEPT WINTER WEATHER ADVISORY UP FOR NORTHERN MOUNTAINS
OF WV AS TEMPS AND DPS STILL BELOW FREEZING IN THE COLD AIR DAMING
AREAS. PRECIP THERE SHOULD START OUT FROZEN AND CHANGE TO FREEZING
RAIN BEFORE CHANGING TO ALL RAIN LATER ON TONIGHT.
PREVIOUS DISCUSSION...
A POTENT STORM SYSTEM...CURRENTLY LOCATED OVER THE SW
U.S. WILL DEEPEN AS IT MOVES SOUTH TOWARDS TEXAS...THEN NORTHEAST
TOWARDS THE REGION TONIGHT...BRINGING A RETURN OF WIDESPREAD
PRECIPITATION TO THE FORECAST AREA. THIS IS A MOIST SYSTEM...WITH
MODELS INDICATING PW VALUES RANGING BETWEEN 1.1 TO 1.3
INCHES...WITH DEEP MOIST SOUNDINGS. RAIN WILL BE HEAVY AT TIMES AS
THIS SYSTEM MOVES THROUGH THE REGION...WITH PRECIPITATION AMOUNTS
OF OVER AN INCH EXPECTED ACROSS MOST OF THE FORECAST AREA.
HEAVIEST RAIN LOOKS TO OCCUR LATE TONIGHT/EARLY WEDNESDAY. MODEL
SOUNDINGS CONTINUE TO INDICATE PRECIPITATION IN THE FORM OF RAIN
ACROSS MOST OF THE CWA...WITH A WINTRY MIX OVER THE HIGHER
TERRAIN...MAINLY RANDOLPH AND POCAHONTAS COUNTIES. THOSE COUNTIES
CAN EXPECT PRECIPITATION TO START AS SNOW...CHANGING TO
SLEET...THEN FREEZING RAIN...BEFORE CHANGING TO ALL RAIN LATE
TONIGHT/EARLY TOMORROW...AS WARMER AIR MOVES INTO THE AREA. NOT
EXPECTING ANY MAJOR ACCUMULATION OF FREEZING RAIN...AS DURATION
SHOULD BE RELATIVELY BRIEF. WILL ISSUE A WINTER WEATHER ADVISORY
FOR THESE COUNTIES TO ACCOUNT FOR THE MIXED PRECIPITATION.
IN ADDITION...A SLIGHT CHANCE FOR THUNDERSTORMS HAS BEEN CONTINUED
IN THE FORECAST FOR TONIGHT AND EARLY TOMORROW. MODELS INDICATING
DECENT LAPSE RATES AS WAA OCCURS AT THE LOW LEVELS...WITH COLDER AIR
AT MID LEVELS...AS WELL AS 850MB THETA E RIDGE. SPC ALSO HAS THE
SOUTHERN PART OF THE CWA IN GENERAL THUNDER FOR TONIGHT/EARLY
TOMORROW.
GUSTY WINDS CAN ALSO BE EXPECTED TO DEVELOP LATER TONIGHT. THIS IS
DUE IN PART TO A TIGHT SURFACE PRESSURE GRADIENT ACROSS THE
CWA...10-12MB...AS WELL AS A 50 TO 60 KT LLJ. WINDS WILL BE GREATEST
OVER THE HIGHER TERRAIN. WILL ISSUE A WIND ADVISORY FOR LATE
TONIGHT THROUGH TOMORROW NIGHT TO ACCOUNT FOR THIS...OVER THE
MOUNTAIN ZONES.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
OCCLUSION WHIPS THROUGH WED AS DEEPENING LOW CENTER TRAVERSES THE
GREAT LAKES. THIS TAKES THE WIDESPREAD RAIN WITH IT...BUT SHOWERS
IN THE WRAP AROUND FLOW WILL QUICKLY FOLLOW...CHANGING TO SNOW
SHOWERS LATE AS THE COLD AIR MOVES IN ON STRONG AND GUSTY NW WINDS.
LEANED A LITTLE TOWARD THE FASTER GFS TIMING GIVEN THE STRENGTH OF
THE FLOW WITH THIS SYSTEM.
TIGHT PRESSURE GRADIENT AND NEARLY ALIGNED FLOW AND GOOD MIXING IN
THE WAKE OF THE FRONTAL PASSAGE WILL ALLOW MUCH OF 50KT H85 FLOW TO
BE REALIZED AS GUSTS ACROSS THE HIGH TERRAIN WED AFTERNOON. THUS
THE WIND ADVISORY CONTINUES THROUGH THE DAY WED. THESE STRONG WINDS
GRADUALLY SUBSIDE WED NT THROUGH THU NT.
THE REMAINDER OF THIS PERIOD IS DRY ALTHOUGH COLD AS HIGH PRESSURE
SAILS ACROSS THE AREA FRI. WEAK ISENTROPIC LIFT...DIVERGENT SW
FLOW ALOFT AND SFC LOW PRESSURE TO THE S LEAD TO INCREASING
CLOUDINESS LATE FRI NT...WITH LIGHT SNOW A SLIGHT POSSIBILITY BY
DAWN SAT ACROSS S PORTION OF AREA.
WITH THE FASTER TIMING...COLD ADVECTION SETS IN JUST QUICKLY ENOUGH
FOR NON DIURNAL DROP IN TEMPERATURE WED AFTN WITH A STEADY DROP
THROUGH THU NT. ROLLED BELOW THE GUIDANCE FOR THE MOST PART
THROUGHOUT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
BY THURSDAY NIGHT...THE STRONG LOW PRESSURE SYSTEM WILL BE LIFTING
THRU THE GREAT LAKES AND NEW ENGLAND. A HIGH PRESSURE BUILDS IN
BRINGING A VERY COLD AND DRY AIR MASS UNDER H8 WINDS AROUND 45 KNOTS
THU NIGHT. THEREFORE...EXPECT DRY WEATHER CONDITIONS WITH CLEAR
SKIES SPREADING FROM THE WEST THROUGH FRIDAY. GUSTY CONDITIONS WILL
STILL POSSIBLE MAINLY HIGHER ELEVATIONS THURSDAY NIGHT...DECREASING
BY FRIDAY. CLEAR SKIES WILL ALLOW IDEAL RADIATIONAL COOLING FOR EVEN
COLDER TEMPERATURES THURSDAY NIGHT.
ANOTHER UPPER WAVE MOVES FROM THE SOUTHERN PLAINS...EAST AND
NORTHEAST INTO THE AREA...TO BRING A MORE SOUTHERLY FLOW INCREASING
TEMPERATURES AND HUMIDITY ON SUNDAY. INTRODUCED SLIGHT CHANCE POPS
ACROSS THE SOUTHERN HALF OF THE AREA...FRI NIGHT...INCREASING TO
CHANCE POPS SATURDAY AND SAT NIGHT. PCPN EXPECTED TO BE ALL SNOW FRI
NIGHT...CHANGING TO RAIN AND MIX SAT ACROSS THE LOWLANDS AS WARM
ADVECTION TAKES PLACE. HOWEVER...PCPN CHANGES BACK TO SNOW SAT NIGHT
AREA WIDE. GOING A BIT FASTER THAN THE LATEST GFS/ECMWF
SOLUTION...MORE LIKE THE ECMWF OLDER SOLUTION. STICK CLOSER TO HPC
TEMPERATURES TWEAKING DOWN FEW DEGREES LOW TEMPS THROUGH THE PERIOD.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A STORM SYSTEM OVER THE SW U.S. IS EXPECTED TO MOVE INTO THE
GREAT LAKES BY TOMORROW MORNING. THE WARM FRONT THIS SYSTEM WILL
SPREAD RAIN FROM SOUTH TO NORTH...HEAVY AT TIMES...LATER THIS
AFTERNOON AND THIS EVENING. EXPECT WIDESPREAD MVFR CONDITIONS TO
DEVELOP BETWEEN 18Z TO 20Z...WITH WIDESPREAD IFR CONDITIONS
EXPECTED AFTER 23Z. GUSTY WINDS WILL ALSO ACCOMPANY THIS
SYSTEM...WITH GUSTS OF UP TO 50 KTS POSSIBLE...AND GUST UP TO 60
KTS OVER THE HIGHER TERRAIN 06Z WED ON. A RUMBLE OR TWO OF THUNDER
IS ALSO POSSIBLE AFTER 06Z WED. MODERATE TO STRONG SW WINDS ALOFT.
RAIN SHOULD END FROM SOUTH TO NORTH BETWEEN 14Z TO 18Z WED WITH
GUSTY WINDS CONTINUING.
AFTER 18Z WEDNESDAY...
WIND GUSTS OF 25 TO 35KTS...AND UP TO 50 TO 60 KNOTS WILL BE
POSSIBLE ESPECIALLY OVER HIGHER TERRAIN IN THE AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WIND ADVISORY FROM 1 AM TO 7 PM EST WEDNESDAY FOR WVZ005>011-
013>020-024>032-039-040.
HIGH WIND WARNING FROM 1 AM TO 7 PM EST WEDNESDAY FOR
WVZ033>038-046-047.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 4 AM EST
WEDNESDAY FOR WVZ046-047.
OH...WIND ADVISORY FROM 1 AM TO 7 PM EST WEDNESDAY FOR OHZ066-067-
075-076-083>087.
KY...WIND ADVISORY FROM 1 AM TO 7 PM EST WEDNESDAY FOR KYZ101>103-
105.
VA...HIGH WIND WARNING FROM 1 AM TO 7 PM EST WEDNESDAY FOR VAZ003-
004.
&&
$$
SYNOPSIS...TRM/SL/JS
NEAR TERM...SL/JS
SHORT TERM...TRM
LONG TERM...ARJ
AVIATION...JS
