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000
FXUS61 KRLX 221025
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
625 AM EDT WED MAY 22 2013

.SYNOPSIS...
A COLD FRONT CROSSES LATE TONIGHT...FOLLOWED BY ANOTHER LATE
THURSDAY.  UPPER LOW CROSSES EARLY FRIDAY...FOLLOWED BY HIGH
PRESSURE...WITH COOLER AND DRIER AIR...FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...
FCST ON TRACK.

PREV DISCN...
TODAY LOOKS LIKE THE MIDDLE DAY OF THE THREE DAYS OF STRONG TO
SEVERE WE SEEM TO GET PRECEDING WARM SEASON COLD FRONTS.  THE
WEATHER TODAY INTO TONIGHT LOOKS TO BE SIMILAR TO THAT OF TUE.

UPPER LEVEL FORCING APPEARS TO REMAIN IN TACT AS IT CROSSES FCST
AREA RIGHT DURING PEAK HEATING...EVEN AS SURFACE COLD FRONT SEEMS TO
LOSE DEFINITION.  AS HEIGHTS FALL...LIX VALUES DROP TO AROUND -6
WHILE CAPE INCREASES TO AT LEAST 2KJ/KG AND WBZ HEIGHTS HOVER AROUND
10KFT.  MEAN MID LAYER FLOW RANGES FROM AROUND 20 KTS SE TO AS HIGH
AS 40 KTS NW...WHICH JIBES WITH SPC/S EASTERN EDGE OF THE SLIGHT
RISK WHICH IS OVER THE MOUNTAINS.  ESSENTIALLY THE ENTIRE AREA IS IN
THE DAY 1 SLIGHT RISK NOW.

WILL KEEP STRONG WORDING IN FCST FOR AFTERNOON AND EVENING
THUNDERSTORMS AND EXPAND HWO THREAT TO ENTIRE FCST AREA.

PW VALUES EXCEED 1.5 INCHES SO HEAVY DOWNPOURS ARE ALSO LIKELY.

THE CONVECTION WILL DIE DOWN OVERNIGHT TONIGHT...BUT NOT AS QUICKLY
AS THIS PAST NT ON ACCOUNT OF THE UPPER LEVEL FORCING AND WHAT IS
LEFT OF THE SFC FRONT.

NO IMPORTANT CHANGES NEEDED TO TEMPERATURES.  HIGHS TODAY WERE
AROUND MIDDLE GROUND IN LIGHT OF LATEST GUIDANCE AND BIAS CORRECTED
GUIDANCE AND WILL BE HIGHLY DEPENDENT ON TIMING OF CLOUDS AND
CONVECTION...SO SAW LITTLE CHANCE FOR IMPROVEMENT UPON PREVIOUS
FCST.  CONVERSELY...SMALL RANGE OF POSSIBILITIES ON LOWS TONIGHT.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
UNSETTLED WEATHER CONTINUES ON THURSDAY...AND PART OF FRIDAY...AS
UPPER TROUGH AND SURFACE COLD FRONT SWEEP ACROSS THE REGION. THIS
WILL KEEP A CHANCE FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR
THE START OF THE SHORT TERM PERIOD. STILL COULD BE SOME STORMS ON
THURSDAY THAT MAY CONTAIN SOME STRONGER WIND GUSTS AS THERE WILL
STILL BE MODERATE WINDS ALOFT...BUT OVERALL INSTABILITY IS
WEAK...AND SO SEVERE RISK IS LOW.

DRIER...COOLER...NORTHWESTERLY FLOW PATTERN WILL TAKE HOLD FOR
FRIDAY THROUGH SATURDAY AS THE UPPER TROUGH PUSHES EAST. DID ELECT
TO LOWER TEMPS SLIGHTLY DURING THIS PERIOD...PARTICULARLY SATURDAY
MORNING...AS GOOD CLEARING...LIGHT SURFACE WINDS EXPECTED AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. MAY BE SOME FOG DEVELOPMENT
ESPECIALLY SATURDAY MORNING UNDER THESE CONDITIONS.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
HAVE GENERALLY FOLLOWED WPC THINKING FOR THIS PORTION OF THE
FORECAST.

HIGH PRESSURE WILL BE IN CONTROL OF THE WEATHER ACROSS THE AREA INTO
SUNDAY NIGHT.  HOWEVER...MODELS SUGGEST A FEW WEAK MID-LEVEL
SHORTWAVE MAY MOVE SOUTHEAST.  BELIEVE AREA SHOULD REMAIN DRY...WITH
A FEW MORE CLOUDS BEGINNING SATURDAY NIGHT

A WARM FRONT WILL THEN DEVELOP AND APPROACH THE REGION ON MONDAY. AS
A RESULT...THERE WILL BE A CHANCE OF SHOWERS AND STORMS MONDAY AND
TUESDAY...MAINLY DURING THE AFTERNOON AND EVENING HOURS.

TEMPERATURES ON SATURDAY SHOULD BE NEAR NORMAL WITH DAYTIME HIGHS IN
THE 70S ACROSS THE LOWLANDS...WITH 60S ACROSS THE HIGHER
ELEVATIONS.  AS THE HIGH PUSHES EAST ON SUNDAY...EXPECT TEMPERATURES
TO WARM TO SLIGHTLY ABOVE NORMAL VALUES MONDAY AND TUESDAY.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
ONCE EARLY MORNING VALLEY FOG IS GONE...VFR MORNING AHEAD OF ANOTHER
DAY OF CONVECTION THAT WILL INITIATE EARLY THIS AFTERNOON.  SHOWERS
AND THUNDERSTORMS WILL BECOME NUMEROUS THIS AFTERNOON AND REMAIN SO
INTO THIS EVENING.  THEY WILL DEVELOP / MOVE IN FROM THE W BUT AT
THE SAME TIME...ELEVATED HEAT SOURCE EFFECT WILL GET STORMS FIRING
OVER THE WV MOUNTAINS.  THIS IS WHY THERE IS A SECOND TSRA GROUP IN
THE MOUNTAIN TAFS FOR LATER TONIGHT.

ANY THUNDERSTORM THIS AFTERNOON AND EVENING COULD PRODUCE IFR
CONDITIONS AND VERY STRONG WIND GUSTS.  THE AREA IS IN A SLIGHT RISK
FOR SEVERE THUNDERSTORMS...MAINLY FOR THIS AFTERNOON AND EVENING AND
CONCERNING WIND GUSTS OF 50 KTS OR GREATER ALONG WITH HAIL TO ONE
INCH IN DIAMETER.

DENSE POST RAIN NOCTURNAL VALLEY FOG IS AGAIN LIKELY IN THE WAKE OF
THUNDERSTORMS TONIGHT.

S TO SW SFC FLOW WILL BECOME A BIT GUSTY OUTSIDE THUNDERSTORMS TODAY
AND THEN LIGHT S TONIGHT.  LIGHT TO MODERATE SW FLOW ALOFT EARLY
THIS MORNING WILL BECOME S TO SW TODAY AND THEN SW OVERNIGHT
TONIGHT...STILL LIGHT TO MODERATE.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...

FORECAST CONFIDENCE...MEDIUM TO HIGH.

ALTERNATE SCENARIOS: TIMING AND DEGREE OF FLIGHT RESTRICTIONS DUE TO
CONVECTION THIS AFTERNOON AND TONIGHT COULD VARY...AS WELL AS TIMING
AND EXTENT OF DENSE VALLEY FOG OVERNIGHT TONIGHT.

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       11   12   13   14   15   16   17   18   19   20   21   22
EDT 1HRLY       07   08   09   10   11   12   13   14   15   16   17   18
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    M    H    M    M    H    H    H    H    H    H
PKB CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H

AFTER 12Z THURSDAY...
IFR CONDITIONS POSSIBLE IN POST RAIN NOCTURNAL VALLEY FOG EARLY THU
MORNING...AND IN VALLEY FOG EARLY SATURDAY MORNING.

&&

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

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...TRM
SHORT TERM...SL
LONG TERM...JSH
AVIATION...TRM