Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 272353
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
650 PM EST THU NOV 27 2014

.SYNOPSIS...
COLDER LOW LEVELS WITH NORTHWEST FLOW/UPSLOPE SNOW SHOWERS THROUGH
TONIGHT. HIGH PRESSURE FRIDAY AND SATURDAY. ANOTHER SYSTEM SUNDAY
INTO MONDAY.

&&

.NEAR TERM /THROUGH FRIDAY/...
TRANSITIONING TO NORTHWEST FLOW IN THE LOWER LEVELS THIS AFTERNOON
WITH A MINOR LEAGUE UPSLOPE SNOW EVENT ON TAP FOR THIS EVENING AND
TONIGHT. COLD ADVECTION BRINGS -10C AND LOWER AIR AT THE 850MB BY
TONIGHT WHICH WILL HELP WITH THE LAPSE RATES AND ALLOW FOR AUTO
CONVECTION TO OCCUR. ADDED THE BULK OF THE CWA INTO SLIGHT CHANCE
POPS IN THIS SCENARIO...THOUGH MOST PRECIPITATION...WHICH MAY BE A
RAIN/SNOW MIX AT AROUND 35F OVER THE NEXT 3 HOURS...SHOULD BE
INSIGNIFICANT. RESERVE THE ACCUMULATION POTENTIAL FOR THE TYPICAL
UPSLOPE AREAS IN THE EASTERN HIGHLANDS...CONCENTRATING ON THE
NORTHERN MOUNTAINS. THINKING THAT THE 2 INCH MARK IS A GOOD NUMBER
FOR MOST AREAS ABOVE ABOUT 2000FT...BUT THE HIGHEST WINDWARD RIDGES
ABOVE 4000FT COULD SEE UP TO 4 INCHES. THIS SHOULD BE ISOLATED
HOWEVER AND WILL NOT PUT OUT ANY HEADLINES. WILL RECOMMEND TO THE
EVENING SHIFT AN SPS MIGHT BE USEFUL LATER THIS EVENING TO COVER
THE LIGHT SNOW.

LAPSE RATES COLLAPSE AFTER 06Z FRIDAY...SO WILL SEE THE END OF THE
MOUNTAIN SNOW BY 12-15Z. WILL GO RIGHT INTO WARM AIR ADVECTION
OVER THE LOW LEVELS IN A TIGHT TEMPERATURE GRADIENT AT 850MB WITH
MOISTURE PROGS HINTING AT A WARM FRONT PUSHING THROUGH FRIDAY
AFTERNOON. THIS IS THE REASON FOR THE RETURN OF THE CLOUDS SO
QUICKLY AFTER THE LOW LEVEL STRATUS FROM THE COLD ADVECTION
DISSOLVES.

GOT ANOTHER DAY OF CHILLY TEMPERATURES AFTER TEENS/20S IN THE
MOUNTAINS/LOWLANDS TONIGHT BEFORE IMPROVEMENT IN THIS AREA THIS
WEEKEND. 40F POSSIBLE IN THE TRI STATE AREA...BUT THAT WILL BE
ABOUT IT.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE OFF TO THE SOUTHEAST TO START THE PERIOD...WITH NW
FLOW ALOFT KEEPING SOME CLOUDS ACROSS THE FORECAST AREA. THINGS DRY
OUT SATURDAY UNDER ZONAL FLOW...THEN TURNING MORE SOUTHWESTERLY BY
LATE IN THE DAY WHICH BEGINS RETURNING LOW LEVEL MOISTURE. HOWEVER
THE ATMOSPHERE REMAINS VERY DRY ABOVE AROUND 800MB. WITH THIS DRY
AIR ALOFT IN PLACE...DELAYED ONSET OF ANY POPS INTO SATURDAY NIGHT.
ENVISION A LOW STRATUS DECK IN PLACE...WITH PERIODS OF LIGHT RAIN
ACROSS WESTERN CWA SATURDAY NIGHT AND SUNDAY.

USED A RAW CONSENSUS BLEND FOR LOWS...WITH A SLIGHTLY NON-DIURNAL
TREND FRIDAY NIGHT AS SURFACE FLOW BECOMES SOUTHERLY. BLENDED
BIAS-CORRECTED ECMWF INTO HIGHS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
USED A BLEND OF THE ECMWF ENSEMBLE MEAN AND THE CURRENT FORECAST.
NEXT FRONTAL BOUNDARY PUSHES INTO THE REGION SUNDAY NIGHT INTO
MONDAY. MODELS THEN SHOW A WAVE MOVING ALONG THE FRONT FOR
TUESDAY...BUT QUESTIONABLE HOW MUCH OF THAT EFFECTS THE CENTRAL
APPALACHIANS. ECMWF AND GFS THEN DIVERGE CONSIDERABLY FOR WEDNESDAY
AND THURSDAY. USING THE ECMWF ENSEMBLE MEAN BRINGS A FRONT THROUGH
ON WEDNESDAY WITH SOME UPSLOPE SNOW POSSIBLE BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
SNOW SHOWERS OF VARYING INTENSITY...BUT MOSTLY 2 TO 4 MILES IN VSBY
OVER WV UPSLOPE TERRAIN...BECOMING LESS NUMEROUS 06Z TO 12Z.
WIDESPREAD CEILINGS 25 HND TO 35 HND FT BKN/OVC ACROSS LOWLANDS
THROUGH 15Z WITH 1 TO 2 THSD FT BKN ACROSS WV MOUNTAINS.

AFTER 15Z FRIDAY...LINGERING STRATOCUMULUS AT 2 TO 3 THSD FT
BECOMING SCATTERED FROM THE SOUTH TO NORTH WITH MID DECK CLOUDS AOA
10 THSD FT INCREASING AND THICKENING 18Z FRIDAY TO 00Z SATURDAY FROM
WNW.

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

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING THE BREAK UP/SCATTERING OF THE
STRATOCUMULUS CEILINGS ON FRIDAY MAY VARY.

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                                                                 FRI
UTC 1HRLY       00   01   02   03   04   05   06   07   08   09   10   11
EST 1HRLY       19   20   21   22   23   00   01   02   03   04   05   06
CRW CONSISTENCY  M    M    M    H    H    H    H    H    H    M    M    M
HTS CONSISTENCY  M    M    M    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  M    M    M    M    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    M    M    M    H    H    H    H    L    L    L
PKB CONSISTENCY  H    M    M    M    H    H    H    H    M    M    M    M
CKB CONSISTENCY  M    L    M    H    H    M    H    H    H    H    H    H

AFTER 00Z SATURDAY...
IFR MAY DEVELOP IN AREAS OF RAIN SUNDAY NIGHT OR MONDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...RPY/MZ/26
NEAR TERM...26
SHORT TERM...MZ
LONG TERM...RPY
AVIATION...KTB










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