Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 160000
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
800 PM EDT MON SEP 15 2014

.SYNOPSIS...
MID LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT PASS TONIGHT AND
EARLY TUESDAY. HIGH PRESSURE RETURNS FOR WEDNESDAY INTO THE WEEKEND.
COLD FRONT POSSIBLY TOWARD THE END OF THE WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...
800 PM UPDATE...
RAISED DEW POINTS S AND LOWERED TEMPERATURES A BIT EARLY ON.
OTHERWISE FCST ON TRACK.

PREV DISCN...
CLOUDS WILL BE ON THE INCREASE THIS EVENING AHEAD OF REINFORCING
COLD FRONT. FLOW INCREASES A BIT TONIGHT BUT OVERALL FORCING
DECREASES WITH FRONT AS IT APPROACHES. IN FACT APPEARS UPPER LEVEL
MOISTURE OUT PACES LOW LEVEL BOUNDARY TONIGHT. SO WHILE SOME SHRA
ARE EXPECTED...THINK GREATEST COVERAGE WILL BE OVER SE OH AND N WV
THIS EVENING. HAVE SOME HIGH CHANCE POPS IN THOSE AREAS WITH LOWER
POPS ELSEWHERE. ELECTED TO ROLL WITH COVERAGE WORDING IN WX GRIDS.
TIMING OF FROPA LOOKS TO BE 03-05Z FOR SE OH...SLOWING DOWN ONCE
INTO WV WITH TIMING 06Z-12Z LOWLANDS AND EXITING SW VA BY EARLY
MIDDAY. INSTABILITY LOOKS TO BE LACKING SO HAVE NEGLECTED MENTION
OF THUNDER. EXPECT SOME POST FRONTAL STRATUS TOMORROW
MORNING...WHICH MAY LINGER INTO EARLY AFTN HRS ALONG AND S OF I64.

ROLLED WITH LOCAL MOS FOR TEMPS TODAY AND TOMORROW...GENERALLY
SPEAKING. TRIED TO STAY A HAIR BELOW GUIDANCE TOMORROW S WV OWING
TO CLOUD COVER.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
HIGH PRESSURE RULES THROUGH THIS PERIOD. MODELS DO HAVE A
DISTURBANCE MOVING THROUGH THE FLOW WEDNESDAY NIGHT INTO
THURSDAY...BUT DUE TO LACK OF LOW LEVEL MOISTURE...EXPECT ONLY SOME
CLOUDS WITH THIS FEATURE.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
FOR FRIDAY AND SATURDAY...USED A BLEND OF THE GFS...ECMWF...GFS
ENSEMBLE MEAN...AND ECMWF ENSEMBLE MEAN. THIS KEEPS THE AREA UNDER
HIGH PRESSURE WITH TEMPERATURES SLOWLY MODERATING SOME. FOR SUNDAY
INTO MONDAY...A COLD FRONT WILL PUSH THROUGH THE AREA. USED A BLEND
OF THE GFS ENSEMBLE MEAN AND THE ECMWF ENSEMBLE MEAN FOR FRONTAL
TIMING.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
SPOTTY LIGHT RAIN OUT OF AN ALTOCU DECK WAS MOVING INTO THE MIDDLE
OHIO VALLEY AS 00Z APPROACHED...OUT AHEAD OF A COLD FRONT THAT WAS
ENTERING NW INDIANA.  THESE FEATURES WILL MOVE ESEWD THROUGH THE
AREA OVERNIGHT.  THE SPOTTY LIGHT RAIN AT NT WILL BE JUST ENOUGH TO
BRING VSBY VALUES DOWN TO 5 TO 6 MILES...THE TOP EDGE OF MVFR.  HAVE
A NOTABLE EXCEPTION AT EKN WITH IFR 06Z-13Z WITH VSBY AS LOW AS 1
MILE THERE.  MOST OF THE GUIDANCE SUGGESTS DENSE /VLIFR/ FOG
OVERNIGHT INTO TUE MORNING ALL SITES BUT BKW...BUT BELIEVE CLOUDS
ASSOCIATED WITH THE FRONT SHOULD PRECLUDE THIS SO FCST IS
CONSIDERABLY MORE OPTIMISTIC.

HOWEVER...CIGS WILL LOWER TO MVFR AS THE FRONT PASSES LATE OVERNIGHT
INTO TUE MORNING.  VSBYS WILL IMPROVE TUE MORNING...BUT MVFR
STRATOCU WILL PERSIST THROUGH THE MORNING N...AND INTO THE AFTERNOON
S.

LIGHT W TO SW SFC FLOW WILL BECOME LIGHT AND VARIABLE
OVERNIGHT...AND THEN N BEHIND THE FRONT ON TUE.  LIGHT TO MODERATE W
FLOW ALOFT WILL BECOME LIGHT TO MODERATE NW TOWARD TUE MORNING...AND
THEN VEER TO THE N WHILE BECOMING LIGHT ON TUE.

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

FORECAST CONFIDENCE: MEDIUM TO HIGH.

ALTERNATE SCENARIOS: TIMING DENSITY OF FOG TONIGHT IN QUESTION. CIGS
MAY VARY AT ONSET LATE OVERNIGHT AND POST FRONTAL TUE.  VSBY FCST IS
OPTIMISTIC COMPARED WITH GUIDANCE OVERNIGHT INTO TUE MORNING.

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
EDT 1HRLY       16   17   18   19   20   21   22   23   00   01   02   03
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    M    M    M    M    H    H    M    M
EKN CONSISTENCY  H    H    H    H    H    H    H    M    H    H    L    L
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 00Z WEDNESDAY...
IFR POSSIBLE IN DENSE VALLEY FOG EARLY WEDNESDAY MORNING.

&&

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

&&

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





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