Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 031805
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
205 PM EDT MON AUG 3 2015

.SYNOPSIS...
A COLD FRONT APPROACHES THIS EVENING...WITH SHOWERS AND
THUNDERSTORMS. HIGH PRESSURE CROSSES TUESDAY INTO WEDNESDAY. A LOW
PRESSURE SYSTEM CROSSES WEDNESDAY NIGHT THROUGH THURSDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
A COLD FRONT APPROACHES FROM THE NORTHWEST EARLY TONIGHT. MODEL
CONSENSUS IS THE BRING SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST
OH BY 00Z TUESDAY AND SPREAD SOUTHEAST AND EAST OVERNIGHT. PLENTY
OF AFTERNOON SUNSHINE PROVIDED ENOUGH HEATING TO GET STORMS GOING.
MODELS INDICATE DEEP LAYERED SHEAR OF ABOUT 50 KNOTS ACROSS THE
NORTHERN PORTIONS OF WV AND SOUTHEAST OH. ALTHOUGH SFC CAPE VALUES
FROM THE NAM SEEMS TO BE EXAGGERATED BY HIGHER DEWPOINTS...STILL
EXPECT ENOUGH BOUYANCY TO PRODUCE STRONG THUNDERSTORMS. SPC HAVE
THE AREA UNDER A SLIGHT RISK FOR SEVERE WEATHER ACROSS NORTHEAST
KY...SOUTHEAST OH AND THE WESTERN HALF OF WV THROUGH TONIGHT.

ADJUSTED POPS TO REFLECT THE CONSENSUS OF MODELS...STARTING PCPN
ACROSS SOUTHEAST OH AROUND 00Z...THEN SPREAD SOUTHEAST AS IT
LOOSEN ITS GRIP BY LOOSING DIURNAL HEATING. HOWEVER...BOUNDARY
LAYER CONVERGENCE LOOKS DESCENT WITH THE FRONT...AND WITH DEEP
LAYERED SHEAR AROUND 50 KNOTS...STORMS COULD LINGER INTO AT LEAST
MIDNIGHT.

BLENDED THE SUPER BLEND NUMBERS WITH PREVIOUS FORECAST FOR
TEMPERATURES THROUGH THE PERIOD.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MAIN HIGHLIGHT THIS PERIOD IS A DRIER FCST FOR TUE INTO WED...AS
HIGH PRESSURE BUILDS BEHIND A COLD FRONT THAT EXITS THE AREA TUE
MORNING. WITH THE COLD FRONT STALLING NOT FAR TO THE S OF THE FCST
AREA...STILL HAVE SCHC POPS ACROSS THE FAR SRN TIER INTO WED.

MODELS CONCUR BROADLY ON THE IDEA OF A SRN STREAM S/W TROUGH AND
SFC LOW PRESSURE SYSTEM APPROACHING FROM THE W BY THU MORNING.
THERE WAS ABOUT A 10MB DIFFERENCE ON THE PRESSURE OF THE SFC LOW
CENTER...THE NAM BEING THE LOWER AT 1001 MB WHICH IS ON THE LOW
SIDE FOR A LOW CENTER IN SRN IL IN MID SUMMER. THE ECMWF IS
SQUARELY IN BETWEEN AND LOOKED REASONABLE.

THE FRONT TO THE S RETURNS AS A WARM FRONT WED AND WED
NT...BRINGING BACK THE CHC FOR SHOWERS AND THUNDERSTORMS COMING IN
FROM THE W IN AN AXIS SHIFTING FROM S TO N AS IT PUSHES E. AS A
RESULT...PRECIPITATION APPEARS MOST LIKELY ACROSS NRN PORTIONS OF
THE FCST AREA BY 12Z THU. PREFERRED THE ECMWF QPF WHICH BEST
DEPICTS THIS. THE BEST CHANCE FOR THUNDERSTORMS WILL BE CLOSE TO
AND S OF THE FRONT...ALTHOUGH ELEVATED THUNDER IS POSSIBLE FARTHER
N EARLY THU MORNING.

TEMPERATURES CLOSE TO STRAIGHT UP GUIDANCE BY DAY AND BIAS
CORRECTED GUIDANCE BY NT. LOWS AND DEW POINT FCST BETTER REFLECT
N-S GRADIENT ASSOCIATED WITH FRONT TO THE S TUE INTO WED.
DIFFERENTIAL CLOUD COVER MUDDLES THE HIGH TEMPERATURE FCST A BIT
ACROSS THE BAROCLINIC ZONE.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
EXTENDED CONTINUES TO PLAY ON THE SURFACE LOW DEVELOPING OFF TO THE
WEST AND MOVING INTO THE CENTRAL APPALACHIANS WARRANTING HIGH END
CHANCE TO LIKELY POPS ON THE FRONT END OF THE LONG TERM. THIS LOW
DEPARTS TO THE EAST BY 18Z FRIDAY AND WILL TAKE THE BULK OF THE RAIN
CHANCES WITH IT. CANADIAN HIGH PRESSURE BUILDS IN BEHIND THE LOW AND
COLD FRONT DRYING IT OUT FOR THE WEEKEND WITH TEMPERATURES SLIGHTLY
BELOW NORMAL AREA WIDE.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS TO START THE PERIOD...BEFORE SHOWERS AND STORMS
DEVELOP LATE THIS AFTERNOON AND EVENING INTO TONIGHT AHEAD OF A
PASSING COLD FRONT. THE COLD FRONT WILL BE ACROSS CENTRAL WV BY
06Z...AND SOUTH OF THE AREA BY 12Z TUESDAY. BRIEF PERIODS OF
IFR/MVFR CONDITIONS EXPECTED WITH THE STRONGER SHOWERS. STRONG
GUSTY WINDS EXPECTED ALONG STRONGER STORMS AS THEY COULD BECOME
SEVERE TONIGHT. DIFFICULT TO PINPOINT WHERE AND WHEN THE STRONGEST
STORMS WILL BE. THEREFORE...CODED VCTS AT MOST SITES FOR
NOW...IMPENDING AMENDMENTS.

BEHIND THE FRONT...LINGERING LIGHT SHOWERS COULD PRODUCE MVFR
CONDITIONS AND LOW CEILINGS OVERNIGHT INTO TUESDAY MORNING.

BULK OF CONVECTION SHOULD WANE AFTER 09Z...BUT WIDESPREAD MVFR
CIGS POSSIBLE MAINLY ACROSS SOUTHERN WEST VIRGINIA...THE MOUNTAINS
OF WEST VIRGINIA...AND SOUTHWEST VA.

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

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING OF CONVECTION AND ASSOCIATED FLIGHT
RESTRICTIONS LATE THIS AFTERNOON AND EVENING COULD VARY.
DEVELOPMENT AND EXTENT OF MVFR CIGS LATE TONIGHT MAY VARY FROM
FORECAST.

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       18   19   20   21   22   23   00   01   02   03   04   05
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
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    M    M    H
PKB CONSISTENCY  H    H    H    M    M    M    M    M    M    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    H

AFTER 18Z TUESDAY...
IFR POSSIBLE AGAIN WEDNESDAY NIGHT AND THURSDAY IN SHOWERS AND
THUNDERSTORMS.

&&

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

&&

$$
SYNOPSIS...JS/ARJ
NEAR TERM...ARJ
SHORT TERM...TRM
LONG TERM...26
AVIATION...ARJ



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