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Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 220001
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
801 PM EDT MON APR 21 2014

.SYNOPSIS...
COLD FRONT CROSSES TUESDAY WITH SHOWERS. HIGH PRESSURE AND COOLER
WEDNESDAY. WARMER BUT DRY ON THURSDAY. ANOTHER WEAK COLD FRONT
CROSSES FRIDAY.

.NEAR TERM /THROUGH TUESDAY/...
-- Changed Discussion --730 PM UPDATE...
OVERALL FORECAST STILL ON TRACK. KRLX AND SURROUNDING RADARS
DEPICTING ECHOES ALOFT BUT WITH THE VERY DRY AIR IN THE LOW
LEVELS...NOT MUCH MAKING IT BELOW ROUGHLY 10KFT AGL AT THIS POINT
IN TIME.

PREVIOUS DISCUSSION...
NOT A LOT OF CHANGE TO THE THINKING FOR THIS PERIOD. CLOUDS WILL
BE LOWERING AND THICKENING WITH TIME DURING THE AFTERNOON AND
EARLY EVENING HOURS. CAN SEE SOME CONVECTIVE CLOUDS TRYING TO FIRE
TO THE WEST OVER KY BUT THEY ARE STRUGGLING IN THE VERY DRY
AIRMASS. AFTER 03Z THIS EVENING...A LOW-LEVEL THETA E RIDGE MAY
PROVIDE A BIT BETTER ENVIRONMENT FOR ANY SHOWERS TO SURVIVE...BUT
THE COLUMN WILL STILL NEED TO MOISTEN UP. KEEPING ANY POPS QUITE
LOW AND CONFINED TO THE WEST FOR THIS REASON.

GOOD MODEL AGREEMENT ON FRONTAL TIMING FOR TUESDAY...BRINGING THE
BOUNDARY CLOSE TO THE OHIO RIVER AROUND 15Z...CRW BY 18Z...AND THE
MOUNTAINS BY 21Z. H500 SHORTWAVE OUT AHEAD WILL PROVIDE LIFT FOR
SOME PRE-FRONTAL ACTIVITY...SO HAVE SOME LIKELY POPS SHOWING UP IN
THE WEST PRIOR TO 12Z. LIKELY POPS THEN DRAG ACROSS CWA WITH THE
FRONT. WITH THE SHORTWAVE OUTRUNNING THE FRONT...SYNOPTIC SUPPORT
WANES WITH TIME. SINCE RAIN WILL STILL BE FIGHTING THE ANTECEDENT
DRY AIRMASS...QPF LOOKS TO TOP OUT AROUND .25 INCH. WITH CAPE
APPROACHING 500 J/KG AND SOME FAVORABLE TIMING...KEPT THE SLIGHT
CHANCE OF THUNDER. NO CHANCE OF SEVERE THOUGH AS SHEAR IS PRETTY
MUCH NONEXISTENT. SHRA SHOULD EXIT FAIRLY QUICKLY WITH BOUNDARY AND
HAVE A DRY CWA BY 00Z WEDNESDAY.

CONTINUING THOUGHT OF TEMPERATURES ABOVE GUIDANCE TONIGHT WITH
CLOUDS. ONLY MINOR CHANGE TO WELL-CLUSTERED NUMBERS FOR TUESDAY.-- End Changed Discussion --

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
IT WILL BE DRY WEDNESDAY AND THURSDAY AS HIGH PRESSURE DOMINATES.
TEMPERATURES WILL BE IN THE 60S WEDNESDAY WITH A NORTH
BREEZE...BUT REBOUND WELL INTO THE 70S BY THURSDAY...AS THE HIGH
SHIFTS EAST AND SOUTHERLY FLOW RETURNS.

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A QUICK WARM UP THURSDAY NIGHT AND FRIDAY AHEAD OF AN APPROACHING
COLD FRONT.

MODELS...ECMWF/GFS CONTINUE IN GOOD AGREEMENT WITH THE TIMING AND
STRENGTH MAINTAINING CONSISTENCY DURING THE PAST FEW
DAYS. BOTH MODELS HAVE SOME CONVECTION AHEAD OF THE FRONT REACHING
SOUTHEAST OH BY 09Z FRIDAY. SHOWERS OR STORMS WILL SPREAD EAST
INTO FRIDAY NIGHT. INTRODUCED LIKELY POPS WITH FRIDAYS COLD FRONT.

MODELS SUGGEST A SECONDARY FRONT SWEEPING ACROSS MAINLY THE NORTHERN
SECTIONS FRIDAY NIGHT INTO EARLY SATURDAY.

THIS TIMING IS NOT DURING THE PEAK DIURNAL HEATING UNDER CUTTING
THUNDERSTORM PROBABILITY. MODELS CONTINUE TO SHOW HIGH DEEP
LAYERED SHEAR AS WITH MOST COLD FRONTS. BUT TOO FAR OUT TO TRUST
THERMODYNAMIC PARAMETERS. KEPT HPC DEWPOINTS AND TEMPERATURES
THROUGH THE PERIOD.

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --00Z TUESDAY THROUGH 00Z WEDNESDAY...
VFR CONDITIONS FOR THE REST OF THE EVENING INTO THE OVERNIGHT HOURS
AS CLOUDS AND MOISTURE GRADUALLY BUILD IN AHEAD OF APPROACHING COLD
FRONT.

A WEAK SHORTWAVE COULD PRODUCE A FEW SHOWERS OUT AHEAD OF THE FRONT
DURING OVERNIGHT HOURS BUT WITH A VERY DRY AIRMASS IN PLACE OUT
AHEAD OF THE FRONT...SHRA SHOULD DEVELOP IN SOUTHEAST OHIO AND
EASTERN KENTUCKY BEGINNING AROUND SUNRISE AND SPREAD EAST ACROSS WEST
VIRGINIA THROUGH THE MORNING AND TAPER OFF IN THE EARLY AFTERNOON
ALONG THE LOWLANDS ENDING IN THE EASTERN MOUNTAINS BY EARLY
EVENING...BRIEF MVFR CONDITIONS ARE POSSIBLE IN THE STRONGEST
SHOWERS ASSOCIATED WITH THE FRONT OTHERWISE EXPECTING CONDITIONS TO
REMAIN IN THE LOW END OF VFR THROUGH MOST OF TOMORROW.

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

FORECAST CONFIDENCE: HIGH.

ALTERNATE SCENARIOS: MINOR TIMING DIFFERENCES MAY SHOW UP.

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 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 00Z WEDNESDAY...
NO IFR CONDITIONS EXPECTED.-- End Changed Discussion --

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

$$
SYNOPSIS...ARJ/RPY/30
NEAR TERM...50/CL
SHORT TERM...RPY
LONG TERM...ARJ
AVIATION...JM

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