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000
FXUS61 KRLX 210541
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
125 AM EDT TUE MAY 21 2013

.SYNOPSIS...
HIGH PRESSURE OVERNIGHT. AFTERNOON CONVECTION TUESDAY AND
WEDNESDAY. COLD FRONT APPROACHES WEDNESDAY AND MOVES ACROSS
THURSDAY. COOLER HIGH PRESSURE FRIDAY AND THE WEEKEND.

&&

.NEAR TERM /THROUGH TODAY/...
INTRODUCE AREAS OF FOG MAINLY OVER AREAS THAT RECEIVED RAIN DURING
THE AFTERNOON HOURS...AND OVER TYGART RIVER AND KANAWHA RIVER
VALLEYS...AND THE SOUTHERN COAL FIELDS OF WEST VIRGINIA DURING THE
PREDAWN HOURS. ADJUSTED HOURLY TEMPS CURVE. REMOVED ALL PCPN
THROUGH 12Z TUESDAY. MODELS SHOWING NO DISTURBANCES AT H5 WITHIN UPPER
RIDGE ACROSS NORTHEAST KY...OH...WV...AND PA. FOR
TUESDAY...AFTERNOON SHOWERS AND STORMS ARE POSSIBLE.

PREVIOUS DISCUSSION BELOW...
RADAR IMAGERY AT 18Z SHOWING SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS MAINLY CONFINED TO THE EASTERN HIGHER TERRAIN AT
THIS POINT. EXPECT THIS PRECIP TO CONTINUE EASTWARD AS THE S/W
TROUGH AND ASSOC VORT MAX RESPONSIBLE FOR TODAY/S PRECIP CONTINUES
EAST AS WELL. LATEST SFC OBS AND RUC13 CONTINUE TO DEPICT SOME SFC
CONVERGENCE WITH WEAK TROUGH ACROSS THE FAR WESTERN ZONES THIS
AFTERNOON. BEST LLVL MOISTURE HAS PUSHED EASTWARD AND NEAR-TERM
CONVECTIVE MODELS DO NOT SHOW ANY REDEVELOPMENT ACROSS THE WEST.
WILL HOWEVER GO AHEAD AND CONTINUE A SLIGHT CHANCE FOR CONVECTION
OUT HERE WITH JUST A PINCH OF LLVL MOISTURE STILL NOTED ON POINT
SOUNDINGS AND PWATS UP AROUND 1.2-1.4 INCHES.

DURING THE OVERNIGHT HOURS TODAY/S S/W TROUGH AND VORT MAX CONTINUE
EASTWARD. PRECIP WILL HAVE ENDED FOR MOST IF NOT ALL LOCATIONS BTWN
00Z-03Z TUE. MOST LOCATIONS WILL REMAIN PRECIP-FREE OVERNIGHT BUT
LATEST NWP GUIDANCE DEPICTING A 2-3KFT LAYER OF CONVECTIVE MOISTURE
PUSHING INTO THE NORTHERN ZONES CENTERED AROUND 850MB AND AROUND 12Z
TUE. SIMULTANEOUSLY 850MB CONVERGENCE NOTED ACROSS THE I-79 CORRIDOR
AS WELL AND THUS WILL BRING IN SLIGHT CHANCE POPS WITH THUNDER WITH
THIS FEATURE. INHERITED MINS IN THE LOW/MID 60S MOST LOWLAND
LOCATIONS LOOK GOOD. WILL CONTINUE TO CARRY AT LEAST A SLIGHT CHANCE
OF SHOWERS/THUNDER MOST LOCATION DURING THE DAY...BUT THE BETTER
CHANCE OF THUNDERSTORMS ARRIVES SE OHIO ZONES BY AND AFTER 21Z AS
BETTER LLVL MOISTURE ARRIVES WITH DECENT SFC CONVERGENCE NOTED SAME
AREA. SHEAR IS WEAK AND THUS ORGANIZATION WILL BE AS WELL WITH
REGARD TO SEVERE POTENTIAL. BUT HEAVY DOWNPOURS WILL BE POSSIBLE AND
WITH SOME STRONG WINDS.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...
MAIN WEATHER MAKER THROUGH THE SHORT TERM WILL BE THE SURFACE COLD
FRONT PASSING WEDNESDAY...AND THEN THE LINGER UPPER LEVEL TROUGH.
FOR TUESDAY NIGHT...MAIN FOCUS IS TO THE WEST...SO DECREASED POPS
SOME...HOWEVER WITH LOTS OF MOISTURE STILL HANGING AROUND COULD NOT
GO DRY SO HAVE SLIGHT CHANCE TO CHANCE POPS FOR MUCH OF THE AREA
OVERNIGHT. COLD FRONT APPROACHES FROM THE WEST WEDNESDAY...WILL
LIKELY BE ONGOING CONVECTION/OUTFLOW BOUNDARIES TO OUR WEST
WEDNESDAY MORNING. WE SHOULD HAVE PLENTY OF INSTABILITY IN THE
WARM SECTOR AHEAD OF THE FRONT...NAM IS SHOWING 2000+ J/KG CAPE
ALONG THE OHIO RIVER AROUND NOON...WITH 30-40KTS BULK SHEER AND
PWATS AROUND 1.5 INCHES. SHOULD SEE A ROUND OF ORGANIZED
CONVECTION OUT AHEAD OF THE COLD FRONT MOVING FROM WEST TO EAST
ACROSS THE CWA. THE MOST LIKELY AREA OF CONCERN FOR STRONG TO
SEVERE STORMS CONTINUES TO BE ALONG AND EITHER SIDE OF THE OHIO
RIVER FROM SE OHIO INTO NORTH CENTRAL WEST VIRGINIA. WILL CONTINUE
HWO MENTION FOR DAMAGING WINDS AND HAIL POTENTIAL. THE ACTUAL COLD
FRONT WILL NOT PASS UNTIL THURSDAY...SO POPS CONTINUE THROUGH THE
SHORT TERM PERIOD.

WEDNESDAY WILL BE A WARM DAY...BUT WITH PLENTY OF CLOUDS SHOULD NOT
BE AS WARM AS TUESDAY. THURSDAY WILL BE ABOUT 10 DEGREES COOLER.
OVERNIGHT LOWS WILL BE MILD WITH LOTS OF CLOUDS AND MOISTURE.
BASED ON RECENT VERIFICATION STATS...BLENDED IN BIAS- CORRECTED
CONSENSUS GUIDANCE FOR BOTH HIGHS AND LOWS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HAVE GENERALLY FOLLOWED WPC THINKING FOR THIS PORTION OF THE FORECAST.

COLD FRONT SHOULD BE LOCATED SOUTHEAST OF THE REGION AT THE
BEGINNING OF THE PERIOD...WITH HIGH PRESSURE BUILDING IN. CHANCE
OF SHOWERS AND STORMS WILL END FROM THE NORTHWEST THURSDAY NIGHT
INTO FRIDAY. HOWEVER...A MID-LEVEL DISTURBANCE MOVING SOUTHEAST
WILL INCREASE THE CHANCES FOR PRECIPITATION ON FRIDAY....MAINLY IN
THE MOUNTAINS AND ADJACENT COUNTIES.

HIGH PRESSURE WILL THEN BE IN CONTROL OF THE AREA INTO MONDAY.
HOWEVER...A WEAK MID-LEVEL DISTURBANCE WILL SLIDE SOUTHEAST SATURDAY
NIGHT INTO SUNDAY.

A WARM FRONT WILL DEVELOP AND APPROACH THE REGION ON MONDAY.  ECMWF
SUGGESTS THERE WILL BE A CHANCE OF SHOWERS AND STORMS MONDAY
AFTERNOON...ESPECIALLY ACROSS THE SOUTH. BECAUSE OF UNCERTAINTY...HAVE
LEFT THESE CHANCES OUT OF THE FORECAST FOR NOW.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
PATCHY DENSE FOG CAN BE EXPECTED IN VALLEYS IN AND JUST WEST OF THE
MOUNTAINS THAT RECEIVED RAIN TODAY. FURTHER WEST AND ON
HILLTOPS...WINDS SHOULD PREVENT THE DENSE FOG. CUMULUS CAN BE
EXPECTED TODAY...WITH AFTERNOON AND EVENING THUNDERSTORMS POSSIBLE.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...

FORECAST CONFIDENCE...MODERATE WITH FOG EARLY THIS MORNING...THEN
HIGH.

ALTERNATE SCENARIOS: SOME UNCERTAINTY ON FOG DENSITY AND COVERAGE
OVERNIGHT. TIMING OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON COULD
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                              TUE 05/21/13
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  M    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    M    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    L    L    L    L    L    L    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 06Z WEDNESDAY...
IFR CONDITIONS POSSIBLE WEDNESDAY WITH SHOWERS AND THUNDERSTORMS.

&&

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

&&

$$
SYNOPSIS...JSH/ARJ/50
NEAR TERM...ARJ/50
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...RPY