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Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 190002
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
748 PM EDT SAT MAY 18 2013

.SYNOPSIS...
MOIST AIR MASS WITH WEAK STEERING CURRENT IN PLACE THROUGH SUNDAY.
REMNANTS OF MID AND UPPER LEVEL WAVE ADDS SUPPORT FOR CONVECTION TOO
THIS WEEKEND. NEW FRONT APPROACHES WEDNESDAY AND THURSDAY.

.NEAR TERM /THROUGH SUNDAY/...
UPPER LEVEL TROUGH AXIS HAS NOW CREPT CLOSER PROVIDING UPPER LEVEL
SUPPORT FOR THE GENERATION OF ASCENT. OTHERWISE...THERE HAS NOT
BEEN MUCH CHANGE TO THE OVERALL ATMOSPHERE FROM THE LAST COUPLE OF
DAYS. PRECIPITABLE WATER VALUES PUSHING 1.5 INCHES WITH A
CONVECTIVE TEMPERATURE IN THE MID 70S. HITTING THAT IN MANY
LOCATIONS ALREADY. FLOW THROUGH THE UPPER LEVELS RESEMBLES JULY
AND AUGUST MORE SO THAN MAY...BUT DO HAVE ENOUGH STEERING FLOW TO
TAKE CELLS SOUTH TO NORTH. OTHERWISE...WILL KEEP THE PULSE NATURE
OF THE EVENT THROUGH THE EVENING.

NEED TO WATCH ADDITIONAL RAINFALL AMOUNTS OVER AN AREA JUST NORTH
OF THE I-64 CORRIDOR WEST TO JUST NORTH OF THE OHIO RIVER...ACROSS
PORTIONS OF THE COAL FIELDS...AND IN THE MOUNTAINS. NOTHING
ALARMING AT THIS POINT IN TIME...AND WILL NOT ISSUE ANY WATCHES
FOR POTENTIAL WATER PROBLEMS WITH THE FEELING THAT ANY ISSUES
WOULD BE ISOLATED.

POPS TO WANE TONIGHT...AND SHOULD SEE CLOUDS TRYING TO SCATTER
OUT. HAVE HIT THE POTENTIAL FOR RIVER VALLEY FOG...ESPECIALLY FOR
PLACES THAT GET WET AGAIN TODAY.

UPPER LEVEL TROUGH AXIS STILL LINGERS INTO SUNDAY...SO CARRY A
PERSISTENCE TYPE FORECAST THROUGH 00Z MONDAY.

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
WITH THE WEAK UPPER LOW DRIFTING EAST OF THE AREA BY MONDAY AND A
WEAK UPPER RIDGE TAKING OVER MONDAY AND TUESDAY...THIS PERIOD LOOKS
TO BE GENERALLY DRY. STILL...ENOUGH LOW LEVEL MOISTURE AND MARGINAL
INSTABILITY AIDED VIA INCREASED SUNSHINE...GIVES RISE TO JUST A
SMALL CHANCE FOR AN AFTERNOON STORM IN A FEW PLACES. WILL KEEP POPS
LOW AND MOSTLY IN THE AFTERNOON. IN ANY EVENT...TEMPERATURES WILL
WARM INTO THE 80S BOTH DAYS WITH THE SUNSHINE...AND MAY ACTUALLY BE
JUST A BIT ON THE MUGGY SIDE WITH RELATIVELY HIGH DEWPOINTS...WHILE
NIGHT TIME LOWS WILL BE WELL INTO THE 60S.

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
-- Changed Discussion --
HPC/ECMWF TRENDING TO GO WITH A STRONGER/FASTER UPPER TROUGH AND
COLD FRONT PUSHING ACROSS THE AREA THURSDAY. RAISED POPS TO CHANCE
WEDNESDAY AHEAD OF THE FRONT IN THE WARM MOIST AND UNSTABLE
AIR...AND UP TO LIKELY THURSDAY WHEN THE ACTUALLY FRONT CROSSES.
RAIN ENDS THURSDAY NIGHT WITH PASSAGE OF THE FRONT. STRONG HIGH
PRESSURE OVER CANADA RIDGES IN...WITH A CHILLY AIR MASS FILTERING IN
FRIDAY AND SATURDAY.

PREVIOUS DISCUSSION...
EXTENDED PERIOD BEGINS WITH CWA IN NE PORTION OF AN UPPER
RIDGE...HOWEVER A SW TROUGH RESIDES ON ERN PERIPHERY OF THIS RIDGE
AND IS SLOW TO PUSH EAST. THIS SHOULD KEEP OUR AREA IN DISTURBED
WEATHER THROUGH DAY 4...WITH PRIMARILY DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS IN THE WV MOUNTAINS. LITTLE BREAK...IF ANY...IN THE
AGITATED WEATHER PATTERN AS NEXT SYSTEM IS QUICK TO MOVE IN FROM
THE WEST TUESDAY. GFS AND ECMWF DIVERGE SOLNS WITH THE HANDLING OF
THE UPPER LEVEL LOW TRACK THROUGH THE GREAT LAKES. RELUCTANT TO GO
ANY HIGHER THAN CHC POPS WITH TIMING DIFFERENCES BETWEEN OPERATIONAL
GUIDANCE. STAYED NEAR WPC GUIDANCE WITH TEMPS THROUGH THE EXTENDED
SAVE FOR LOCAL ADJUSTMENTS.-- End Changed Discussion --

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --BASED ON TRENDS SINCE 21Z SATURDAY...HOW GOT RAIN AND HOW DID NOT...
WILL MAKE SOME ADJUSTMENTS FOR THE OVERNIGHT FOG. BASED ON THE SE
FLOW AT 925 MB MAINTAINING ITSELF OVERNIGHT...AND THE LACK OF RAIN
AROUND CRW DURING THE LATE AFTERNOON/EVENING...WILL BE MORE
OPTIMISTIC AND HAVE LESS FOG DEVELOPMENT 06Z TO 12Z. ON THE OTHER
HAND...HAVE INCREASE FOG A BIT FOR THE MID OHIO VALLEY AROUND ATHENS
AND PARKERSBURG.

STILL BELIEVE CEILINGS WILL LOWER ON THE SE UPSLOPE THROUGH THE
GREENBRIER RIVER VALLEY AND INTO THE SOUTHERN MOUNTAINS TO INCLUDE
BKW OVERNIGHT.

HOWEVER...WEST OF THE MOUNTAINS...MOST MODEL SOUNDINGS SHOULD
CONSIDERABLE MOISTURE 2 TO 3 THSD FT BY 06Z TO 12Z SUNDAY...BUT
UNSURE OF COVERAGE OF THAT MOISTURE IN TERMS OF CLOUDS AND
CEILINGS.

SO CONFIDENCE DROPS IN CEILINGS FOR 12Z TO 15Z SUNDAY. WILL TRY TO
BE SOONER THAN PAST 2 DAYS IN HAVING MORE CLOUDS ACROSS WESTERN
LOWLANDS.

HAVE CONSIDERABLE SHOWER ACTIVITY ON SUNDAY...BUT COVERAGE OF
THUNDER IS UNCERTAIN. MODEL SOUNDINGS ONLY SHOWING VERY SKINNY
POSITIVE CAPE AREA.

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

FORECAST CONFIDENCE...MEDIUM.

ALTERNATE SCENARIOS: COVERAGE AND HEIGHT OF CEILINGS 09Z TO 15Z
SUNDAY 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 SUN 05/19/13
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H M M L L L
HTS CONSISTENCY M H H H M M M M M L L L
BKW CONSISTENCY H M M M M M L L M M H M
EKN CONSISTENCY M M M M M M M L L L L L
PKB CONSISTENCY M H H M M M L L M L L L
CKB CONSISTENCY M H H H H H H H M M M M

AFTER 00Z MONDAY...
IF PARTIAL CLEARING DEVELOPS OVERNIGHT SUNDAY NIGHT...IFR FOG
POSSIBLE FOR DAWN MONDAY.-- End Changed Discussion --

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

$$
SYNOPSIS...FB/26
NEAR TERM...26
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...KTB

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