Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 260226
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
926 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/...
925 PM UPDATE...TWEAKED TEMPERATURE GRIDS TO BETTER REPRESENT
CURRENT CONDITIONS. AT THIS POINT...FELT NO CHANGES TO CURRENT
HEADLINES ARE WARRANTED. ALTHOUGH SNOW IS EXPECTED TO THE WEST OF
THE HEADLINES...MODEL SOUNDINGS SUGGEST MANY LOCATIONS WILL HAVE
SURFACE TEMPERATURES JUST ABOVE FREEZING...THUS LIMITING
ACCUMULATIONS...AND THAT PERIOD OF GOOD CRYSTAL GROWTH...AND THUS
HEAVIER SNOWFALL POTENTIAL DURATION...WILL BE SOMEWHAT SHORT
LIVED. WILL LEAVE ALL HEADLINES AS IS.


PREVIOUS DISCUSSION FOLLOWS...
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 /03Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS EXPECTED AT ALL SITES THROUGH 06Z. CLOUDS WILL
THICKEN AND LOWER...AND PRECIPITATION WILL SPREAD INTO THE AREA
FROM SOUTH/EAST TO NORTH/WEST AS A LOW MOVES NORTH ALONG THE
COAST...GENERALLY AFTER 06Z. EXPECT PRECIPITATION TO START OUT IN
THE FORM OF A RAIN/SNOW MIX...GENERALLY ABOVE 2500 FEET...WITH
RAIN BELOW 2500 FEET ELEVATION 06-12Z...WITH SNOW AREA WIDE AFTER
12Z. EXPECT WIDESPREAD MVFR/IFR CONDITIONS...GENERALLY AFTER
12-15Z...PARTICULARLY ACROSS WEST VIRGINIA...AND VA. SOME GENERAL
IMPROVEMENT IN CONDITIONS AFTER 21Z AS THE LOW EXITS TO THE NORTH
AND EAST...HOWEVER...MVFR AND LOCAL IFR CIGS WILL CONTINUE TO
LINGER...PARTICULARLY ACROSS THE HIGHER TERRAIN.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...


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.

DATE                                                       WED 11/26/14
UTC 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
EST 1HRLY       21   22   23   00   01   02   03   04   05   06   07   08
CRW CONSISTENCY  H    H    H    H    H    H    M    L    L    M    M    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    M    L    M    L    M    M    M
EKN CONSISTENCY  H    H    H    H    H    H    M    L    L    M    M    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    M    L    L    L    L    M

AFTER 00Z THURSDAY...
IFR CONDITIONS IN SNOW SHOWERS AND STRATUS OVER THE MOUNTAINS AT
TIMES 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 UNTIL 1 PM EST WEDNESDAY FOR
     WVZ033>036.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR VAZ003-
     004.

&&

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








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