Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 252103
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
403 PM EST TUE NOV 25 2014

.SYNOPSIS...
LOW PRESSURE MOVING UP THE EAST COAST WEDNESDAY BRINGS SNOW TO THE
APPALACHIANS. A WEAKER CLIPPER SYSTEM CROSSES THE CENTRAL OR
SOUTHERN APPALACHIANS WEDNESDAY NIGHT. HIGH PRESSURE FRIDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
ATTENTION TURNS TO FAST MOVING SYSTEM SLATED TO MOVE IN OVERNIGHT
AND EXIT TOMORROW AFTERNOON. LOOKS AS IF MOST OF OUR CONCERN WILL
COME WITH SHARP S/W TROF ROTATING THRU AS OPPOSED TO DEVELOPING
SURFACE LOW ALONG THE E COAST. WHILE THE W EXTENT OF THE PRECIP IS
BY AND LARGE SIMILAR AMONGST THE NAM AND GLOBAL MODELS...AMOUNT
AND THERMAL PROFILES DIFFER. THIS MAKES FOR A CHALLENGING FORECAST
REGARDING WINTER WEATHER. THE MESO NAM IS WETTER AND COLDER IN
THE LOWER PORTIONS OF THE BL.../BELOW 3 KFT/ THAN GFS. THE NEW
ECMWF ALONG WITH SREF TEND TO SIDE WITH NAM FOR THERMAL PROFILES
BUT WITH LESS QPF. AFTER COORDINATION WITH WPC...WENT MORE TOWARD
THE GFS AND NAM 4 KM FOR THERMAL PROFILES WITH LITTLE IN THE WAY
OFF CAA TO WORK OFF. AS FOR QPF A BLEND OF GFS AND SREF WAS USED.
ALL OF THIS RESULTED IN PRECIPITATION QUICKLY OVERSPREADING SW VA
AND E HALF OF WV AFTER MIDNIGHT. EXPECT THIS TO INITIALLY TAKE THE
FORM OF RAIN IN THE LOWLANDS AND FOR ELEVATIONS BELOW 2500 FEET IN
THE MOUNTAINS. AS THE BL COOLS EXPECT A SWITCH TO SNOW ACROSS THE
LOWER ELEVATIONS OF THE MOUNTAINOUS COUNTIES FIRST...FOLLOWED BY
LOWLANDS E OF US 119 IN THE S AND ALONG AND E OF I79 IN THE N
TOWARD MORNING. THE S/W TROF QUICKLY MOVES THRU WITH SURFACE LOW
RACING NE JUST OFF THE E COAST. AS SUCH...QUICKLY BRING POPS DOWN
FROM SW TO NE...SO THAT BY EARLY AFTERNOON THE CWA SHOULD BE DRY
BY AND LARGE.

AS FOR ACCUMULATIONS...HAVE A GENERAL 4 TO 8 FOR RANDOLPH AND
POCAHONTAS WHERE THE WATCH WAS UPGRADED TO A WARNING. HOISTED AN
ADVISORY FOR THE REMAINDER OF THE WV MOUNTAINS DOWN INTO SW VA FOR
1 TO 3 INCHES WITH 2 TO 4 FOR THE CENTRAL MOUNTAINS. ALSO PUT
ADJACENT LOWLAND COUNTIES OF THE N MOUNTAINS IN AN ADV FOR 1 TO 3
INCHES. THERE WILL BE A SHARP CUTOFF TO PRECIP WITH AREAS OF SE OH
STAYING MAINLY DRY PERHAPS. HAVE LITTLE TO NO ACCUMULATIONS IN THE
W LOWLANDS INCLUDING THE CRW/PKB/HTS METRO AREAS. SHOULD THE
COLDER AND WETTER NAM TRENDS CONT...THEN A LITTLE MORE IN THE WAY
OF ACCUMULATIONS MAY MAKE IT INTO THE KANAWHA VALLEY.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
NAM12 IS ODD MODEL OUT IN BRINGING ALBERTA CLIPPER S OF THE AREA WED
NT INTO THU MORNING.  TOOK AN IN BETWEEN SOLN WITH HIGH CHANCE POPS
S LATE WED NT AND LIKELY SNOW SHOWERS IN THE MOUNTAINS INTO THU.
EXPECT ACCUMULATIONS EVEN THERE ONLY AN INCH OR TWO.  WEAK UPSLOPE
FLOW RE-INVIGORATES A BIT THU NT AS H85 TEMPERATURES DIP BELOW
-10C.  THIS BRINGS A BRIEF RETURN OF LIKELY SNOW SHOWERS IN THE
MOUNTAINS OVERNIGHT THU NT.  HIGH PRESSURE THEN BRINGS DRY WEATHER
FOR FRI...CUTTING OFF THE UPSLOPE FLOW FIRST THING IN THE MORNING.

NO MAJOR CHANGES NEEDED TO TEMPERATURES...WHICH WERE CLOSE TO
GUIDANCE MEANS AND BELOW NORMAL ESPECIALLY ON HIGHS.  WARM ADVECTION
AT H85 AND ABOVE IS NOT REALIZED BELOW THE INVERSION FOR HIGHS FRI.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
USED A BLEND OF THE ECMWF AND ECMWF ENSEMBLE MEAN FOR THE FORECAST.
HIGH PRESSURE SLIDES EASTWARD FRIDAY NIGHT AND SATURDAY...PROVIDING
WARM AIR ADVECTION. NEXT FRONTAL BOUNDARY PUSHES INTO THE REGION ON
SUNDAY OR SUNDAY NIGHT. THE FRONT THEN HANGS NEAR THE AREA ON MONDAY
AS A WAVE MOVES ALONG THE FRONT...PUSHING IT SOUTHWARD MONDAY NIGHT.
THE FRONT WILL RETURN BACK NORTHWARD TUESDAY AS A WARM FRONT.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
EXPECT VFR CONDITIONS AT ALL SITES THROUGH THIS EVENING...UNDER
LIGHT WEST SOUTHWEST FLOW.

A LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP AND TRACK NORTH ALONG
THE EASTERN SEA BOARD WEDNESDAY. PRECIPITATION WILL QUICKLY
OVERSPREAD MUCH OF THE AREA AFTER MIDNIGHT WITH MAINLY RAIN IN THE
LOWER ELEVATIONS WITH DEVELOPING MVFR CONDITIONS AND IFR OR WORSE
SNOW IN THE MOUNTAINS TO INCLUDE KBKW AND KEKN BY 09Z. THE RAIN MAY
CHANGE TO SNOW ACROSS THE LOWLAND TERMINALS BEFORE ENDING WEDNESDAY
MORNING...WITH THE GREATEST CHANCE AT IFR CONDITIONS AT KCKB AND
KCRW. THIS SYSTEM QUICKLY EXITS OFF TO THE NE BY EARLY AFTERNOON
WITH IMPROVING CONDITIONS FROM SW TO NE. SOME MVFR STRATUS MAY
LINGER THOUGH.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...

FORECAST CONFIDENCE: HIGH.

ALTERNATE SCENARIOS: TIMING PRECIP AND ASSOCIATED CONDITIONS MAY
VARY LATE TONIGHT AND EARLY WEDNESDAY.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       20   21   22   23   00   01   02   03   04   05   06   07
EST 1HRLY       15   16   17   18   19   20   21   22   23   00   01   02
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z WEDNESDAY...
IFR CONDITIONS IN SNOW SHOWERS OVER THE MOUNTAINS AT TIMES WEDNESDAY
AFTERNOON INTO THURSDAY NIGHT.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 1 AM TO 4 PM EST WEDNESDAY FOR
     WVZ032-037>040.
     WINTER STORM WARNING FROM 1 AM TO 4 PM EST WEDNESDAY FOR
     WVZ046-047.
     WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
     WEDNESDAY FOR WVZ033>036.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
     WEDNESDAY FOR VAZ003-004.

&&

$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...30
SHORT TERM...TRM
LONG TERM...RPY
AVIATION...30





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