-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 150818
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
418 AM EDT WED MAY 15 2013

.SYNOPSIS...
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WARMER AIRMASS BEHIND WARM FRONT TODAY. COLD FRONT APPROACHES
FROM THE NORTH WEDNESDAY NIGHT...AND STALLS OVER THE AREA THURSDAY
INTO THE WEEKEND. UPPER LEVEL SHORTWAVE PASSES SOUTH.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
130 AM UPDATE...RAISED MINS A FEW DEGREES ACROSS THE WEST. ALSO
CODED UP A NON-DIURNAL TEMP PATTERN OVERNIGHT AS IT IS LIKELY THAT
LOCATIONS ACROSS CENTRAL AND WESTERN ZONES HAVE ALREADY REALIZED
THEIR RESPECTIVE OVERNIGHT LOWS AND WILL ESSENTIALLY REMAIN STEADY
OR CONTINUE A SLOW CLIMB TOWARDS DAWN. FURTHER EAST...CURRENT
TEMPS MAY DROP A BIT OVER THE NEXT 1-2 HRS...BUT WILL ALSO BEGIN
TO CLIMB AS THE WARM FRONT CONTINUES TO MARCH EASTWARD. ALSO
WATCHING A BATCH OF LIGHT SHOWERS CURRENTLY TO THE NORTH/NORTHWEST
OF THE AREA. AT THIS POINT IT LOOKS LIKE IT WILL MISS THE FORECAST
AREA TO THE NORTHEAST BUT MAY REQUIRE A TWEAK AT LEAST IN SKY
COVER FOR A FEW HOURS NEAR DAWN.

10 PM UPDATE...NO MAJOR CHANGES NEEDED TO FORECAST.

PREVIOUS DISCUSSION FOLLOWS...
TRICKY FORECAST WITH THE YES/NO FACTOR OF PRECIPITATION THIS
EVENING THROUGH DAWN WEDNESDAY.

WARM FRONT PUSHING THROUGH ALOFT...AND WILL FIND THE CWA IN VERY
DIFFERENT ATMOSPHERE COME THIS TIME WEDNESDAY. AT THE
SURFACE...WARM FRONT IS LIKELY BACK IN INDIANA/CENTRAL KENTUCKY AS
EVIDENCED BY TEMPERATURES AND DEWPOINTS. MID LEVEL DECK FROM WARM
FRONT/VORT MAX NOW IN THE MOUNTAINS WHERE IT COULD LINGER FOR A
FEW MORE HOURS...WITH MORE SCATTERED CLOUDS IN ITS WAKE. NORTHWEST
FLOW ALOFT TO KEEP HINTS OF PVA RUNNING THROUGH THE NORTHERN ZONES
THIS EVENING AND TONIGHT. SOME HINTS OF PATCHY DEFORMATION OVER
THE LOW TO MID LEVELS...BUT TWO INHIBITING PROBLEMS. FIRST IS THE
LACK OF MOISTURE. TONIGHT...WITH SHALLOW LAYER OF SATURATION
OCCURRING NEAR THE INVERSION AND ANOTHER UP AROUND THE 600MB LEVEL
MAY NOT PROVIDE ENOUGH MOISTURE IN WEAK ELEVATED ASCENT. SECOND IS
A SECOND INVERSION ALOFT IN THE 750-700MB LAYER. CANNOT DECISIVELY
SAY THAT NO PRECIPITATION WILL REACH THE GROUND...BUT THE BET ON
THIS FORECAST IS NOTHING MEASURABLE WILL FALL. CAPPED THE POPS AT
14 PERCENT AND ADDED SPRINKLES TO THE 14 VALUE. SHOULD SEE SOME
SLIGHTLY WET SURFACES FROM PERRY TO POCAHONTAS.

COLUMN RETURNS TO A PRIMARILY DRY STATE WEDNESDAY...WITH SOME
RELATIVELY HIGH BASED CUMULUS IN PLACE FROM BOUNDARY LAYER MIXING.
850MB TEMPERATURES HIT THE UPPER TEENS...TRANSLATING TO A JOLT IN
THE MAXIMUM TEMPERATURES WEDNESDAY TO WELL ABOVE NORMAL.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
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MODELS IN AGREEMENT ON APPROACHING COLD FRONT TIMING AND LOCATION...STALLING
WEST TO EAST ACROSS THE AREA THURSDAY INTO AT LEAST SATURDAY. THE
NAM LOOKS MORE ASSERTIVE WITH GFS ON TOTAL DEFORMATION BANDS
ORIENTED WEST TO EAST MOVING SOUTH AS IT WEAKENS THURSDAY...AND
ANOTHER BAND MOVING SOUTH THROUGH OUR NORTH FRIDAY. PW FROM 1.33
TO 1.50 INCHES...AND THETA-E TONGUE UP TO 340K WITHIN THE BOUNDARY
LAYER MAY SUGGEST SUFFICIENT MOISTURE AVAILABLE. TOGETHER WITH
BOUNDARY LAYER CONVERGENCE...MODELS SHOW SFC BASED CAPE EXCEEDING
1200 J/KG...DEWPOINTS IN THE MID 60S...IN A LOW DEEP SHEAR
ENVIRONMENT...MAINLY ALONG QUASI STATIONARY BOUNDARY BY 00Z
FRIDAY.

FAVORED OH RFC QPF MAXIMUM LOCATIONS...BUT CLOSER TO WPC INTENSITY
NEARING 0.75 INCHES THURSDAY THRU 00Z FRIDAY...WITH AN ADDITIONAL
0.50 INCHES THRU 00Z SUNDAY. ADJUSTED POPS ACCORDINGLY...LEAVING THUNDER
ON THE WEATHER GRIDS.

UNIDIRECTIONAL WEAK DEEP LAYER SHEAR COULD PROMOTES PULSE...SLOW
MOVING STORMS THURSDAY AND FRIDAY. ON SATURDAY...MODELS SHOW A
SPREAD SOLUTION IN H5 VORT MAXES ASSOCIATED WITH A WEAKENING
SHORTWAVE PASSING SOUTH SATURDAY INTO SUNDAY. REPETITIVE RAIN
SHOWERS INTO THE WEEKEND MAY RESULT IN SOME WATER PROBLEMS.

WENT A DEGREE LOWER THAN SIMILAR MET/MAV GUIDANCE FOR HIGHS
THURSDAY AND FRIDAY. USED BIAS CORRECTED GFS/GMOS FOR HIGHS
SATURDAY AND LOWS THROUGH THE PERIOD.
-- End Changed Discussion --

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
HAVE FOLLOWED WPC THINKING FOR THIS PORTION OF THE FORECAST. STATIONARY
FRONT WILL LIFT NORTH AS A WARM FRONT BY EARLY SUNDAY...LEAVING THE
REGION IN THE WARM SECTOR FOR THE REMAINDER OF THE PERIOD. EXPECT A
CHANCE OF SHOWERS AND STORMS ALMOST EVERY PERIOD...WITH THE GREATEST
CONCENTRATION AND INTENSITY DURING THE AFTERNOON AND EVENING HOURS.

WPC TEMPS LOOKED GOOD...SO WERE USED WITH SOME MINOR TWEAKS.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
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SOUTHWEST FLOW PICKS UP AHEAD OF THE APPROACHING FRONTAL BOUNDARY
MAINLY AFTER 12Z WITH GUSTS AROUND 20-25KTS IN THE LOWLANDS BY 18Z
WED AND MID TO UPPER 20S IN HIGHER TERRAIN. ALSO OF NOTE IS THE
STRONG LOW LEVEL JET WHICH HAS DEVELOPED OVER THE AREA...WITH WIND
SPEEDS AT CRW CURRENTLY AROUND 50-60KTS AT ABOUT 3KFT. HAVE
INCLUDED A WIND SHEAR GROUP AT CRW FOR THIS. MID LEVEL CLOUDS
WILL LINGER THROUGH THE OVERNIGHT IN NORTHWEST FLOW...CANT RULE
OUT A SPRINKLE IN THE NORTHERN ZONES OVERNIGHT PARTICULARLY
PKB/CKB/EKN...VFR CONDITIONS PERSIST THROUGH TOMORROW WITH PRECIP
CHANCES INCREASING IN SE OH MAINLY AROUND AND AFTER 00Z THU AS THE
AFOREMENTIONED FRONT APPROACHES. AT THIS POINT IT APPEARS CIGS
SHOULD REMAIN LOW VFR WITH THIS ACTIVITY BUT MVFR AND INTERMITTENT
IFR VIS WILL BE POSSIBLE IN THE STRONGER SHOWERS OR THUNDERSTORMS.

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

FORECAST CONFIDENCE...HIGH

ALTERNATE SCENARIOS: TIMING OF FRONTAL BOUNDARY IN SE OHIO MAY BE
DIFFERENT FROM CURRENT 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.

DATE                    WED 05/15/13
UTC 1HRLY       08   09   10   11   12   13   14   15   16   17   18   19
EDT 1HRLY       04   05   06   07   08   09   10   11   12   13   14   15
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    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    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 THURSDAY...
BRIEF/INTERMITTENT IFR POSSIBLE IN HEAVIER SHOWERS/THUNDERSTORMS
WEDNESDAY NIGHT THROUGH FRIDAY...POSSIBLY LONGER.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...JSH/ARJ/30/26
NEAR TERM...50/SL/26
SHORT TERM...ARJ
LONG TERM...JSH
AVIATION...50