Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 020044 CCA
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
755 PM EDT FRI AUG 1 2014

.SYNOPSIS...
UPPER LEVEL DISTURBANCES CROSS TONIGHT INTO SATURDAY...AHEAD OF AN
UPPER LEVEL LOW THAT CROSSES LATE SATURDAY AND SUNDAY.  HIGH
PRESSURE CROSSES EARLY NEXT WEEK.  A WEAK FRONT MAY CROSS MID WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
730 PM UPDATE...
SCATTERED SHOWERS PRIMARILY NEAR AND NORTHWEST OF THE OHIO RIVER
AT THIS TIME BEGINNING TO SHOW SIGNS OF WINDING DOWN. MASSAGED
POPS TO REFLECT MID-CHANCE POPS HERE OVER THE COURSE OF THE NEXT 2
OR SO HOURS. NOTHING REALLY GOING ON ACROSS THE SOUTHEAST HALF OF
THE FORECAST AREA...WITH GENERAL STRATIFORM PRECIP SHIELD WELL OFF
TO THE SOUTHEAST. IT APPEARS ONCE AGAIN THAT THE LATEST NAM RUN MAY
BE TOO FAR NORTH AND WEST WITH TOMORROW/S SYSTEM...BUT WILL TAKE A
BETTER LOOK AT THIS FOR NEXT UPDATE.

PREVIOUS DISCUSSION...
SHOWERS HAVE BEGUN FORMING IN THE HEAT OF THE DAY JUST W OF THE
CLOUD SHIELD ASSOCIATED WITH A WAVE MOVING UP THE E COAST...WITH
SOME TALL ENOUGH FOR LIGHTNING AT TIMES. WEAK SFC CONVERGENCE AND
MODEST UPPER LEVEL DIVERGENCE APPEAR TO BE SUPPORTING THIS
DEVELOPMENT...WHICH SHIFTS SLOWLY NWWD THIS AFTERNOON AND THEN
DISSIPATES WITH THE LOSS OF HEATING THIS EVENING.

THE AREA REMAINS UNDER UPPER LEVEL TROUGHING THROUGH SAT.  MODELS
DEPICT YET ANOTHER WAVE AHEAD OF THE MAIN UPPER LEVEL LOW MOVING UP
OVER THE AREA LATE TONIGHT INTO SAT.  AN UPPER LEVEL LOW APPROACHING
FROM THE W ON SAT THEN APPEARS TO COMBINE WITH THE WAVE AND FORM A
COMMA HEAD PRECIPITATION SHIELD OVER THE MIDDLE OHIO VALLEY SAT
AFTERNOON.  WHILE THERE IS UNCERTAINTY WITH COVERAGE / TIMING OF
PRECIPITATION WITH ALL OF THESE DETAILS...FCST CAPE AND PW VALUES
APPEAR TO BE MODEST ENOUGH TO PRECLUDE WIND OR HEAVY RAIN IMPACTS OF
IMPORT.  AFTERNOON AND EVENING THUNDER WILL BE ABSENT ALIGHTED IN
STABLE AIR BENEATH THE MAIN CLOUD SHIELD...WHICH MOVES UP THE
MOUNTAINS THIS AFTERNOON AND THEN WILL BE MOVING OUT OF THE NRN
MOUNTAINS LATE SAT.

A BIAS CORRECTED BLEND HAS BEEN WORKING FOR LOWS.  GUIDANCE REFLECTS
DIFFERENCES CREATED BY MODEL DEPICTION OF WAVE SAT...THE GFS LESS
DEFINED WITH IT AND THE MAV HIGHER AS A RESULT...COMPARED WITH THE
MET.  TRENDED FCST A LITTLE LOWER THAN PREVIOUS.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
UPPER SHORTWAVE WILL DIG SOUTH AND EAST ACROSS THE AREA ON
SUNDAY...WITH ADDITIONAL SHOWERS AND THUNDERSTORMS...PARTICULARLY
DURING DAYTIME HEATING HOURS. DRIER WEATHER WILL THEN RETURN FOR
MOST OF THE AREA FOR EARLY NEXT WEEK AS HIGH PRESSURE BUILDS IN FROM
THE WEST...HOWEVER...WEAK DISTURBANCES MOVING ACROSS THE SOUTH WILL
STILL KEEP A MENTION IN FAR SOUTHERN/EASTERN ZONES DURING THIS
PERIOD. ALTHOUGH TEMPERATURES WILL WARM DURING THE PERIOD...MODELS
ARE STARTING TO INDICATE UPPER TROUGH REMAINING IN PLACE ACROSS THE
EASTERN HALF OF THE U.S. NEXT WEEK. STARTED TO FOLLOW THE HPC TREND
OF COOLING TEMPERATURES FROM PREVIOUS FORECAST OF HIGHS IN UPPER 80S.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
UNSETTLED WEATHER...ALONG WITH AN INCREASE IN HUMIDITY...EXPECTED
FOR THE REMAINDER OF THE EXTENDED PERIOD. A FRONTAL BOUNDARY WILL
SLOWLY SAG SOUTH WEDNESDAY INTO THE REMAINDER OF THE
EXTENDED...CREATING ADDITIONAL CHANCES FOR SHOWERS AND
THUNDERSTORMS. STILL SOME UNCERTAINTY AS TO HOW FAR SOUTH THE
BOUNDARY WILL MAKE IT/TIMING...SO HELD ONTO SLIGHT CHANCE TO CHANCE
POPS FOR REMAINDER OF EXTENDED PERIOD.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...

SOME REMAINING SCATTERED SHOWERS CURRENTLY NEAR AND NORTHWEST OF
THE INTERSTATE 79 CORRIDOR SHOULD FOR THE MOST PART CONTINUE TO
SLOWLY DISSIPATE OVER THE COURSE OF THE NEXT 2-3 HOURS WITH THE
LOSS OF DAYTIME HEATING. WILL KEEP A SLIGHT CHANCE OF A LIGHT
SHOWER OVERNIGHT HOWEVER.

MIDLEVEL CLOUDS SHOULD PREVENT MUCH IN THE WAY FO DENSE FOG
TONIGHT BUT KEPT A HIGH IFR VIS FOR MOST LOCATIONS PER PREVIOUS
SHIFT...WITH REDUCTION IN VISBYS STILL OCCURING EVEN WITH CLOUDS
IN PLACE.

SHORT TERM GUIDANCE CONTINUES TO INDICATE LOW MVFR CIGS FOR THE
EASTERN MOUNTAINS BY THE NEAR-DAWN HOURS. NEAR-TERM GUIDANCE
HOWEVER STILL NOT AS BULLISH ON THIS SCENARIO...MUCH LIKE LAST
NIGHT. BLF IS HOWEVER CURRENTLY WITH A MVFR CIG...SO WILL CONTINUE
MVFR CIGS IN TAF FOR THIS ISSUANCE AND CONTINUE TO MONITOR.

ANOTHER WAVE OF LOW PRESSURE MAY BRING SHOWERS TO WV LATE OVERNIGHT
AND SAT.  HAVE STAYED AWAY FROM AVIATION RESTRICTIONS FOR NOW ON
ACCOUNT OF UNCERTAINTY.

CALM TO VERY LIGHT WINDS OVERNIGHT WILL SET UP LIGHT OUT OF THE
NORTH AND NORTHEAST DURING THE DAY SATURDAY WITH THE PASSAGE OF A
SURFACE LOW.

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

FORECAST CONFIDENCE: MEDIUM TO HIGH.

ALTERNATE SCENARIOS: EXTENT OF FOG FORMATION MAY VARY OVERNIGHT
TONIGHT INTO SAT MORNING. SHOWERS MAY BECOME WIDESPREAD ENOUGH FOR
AVIATION RESTRICTIONS LATE OVERNIGHT TONIGHT AND SAT. FORMATION OF
MVFR STRATOCU IN THE MOUNTAINS TONIGHT AND IN NRN WV SAT IS IN
QUESTION.

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                                                            SAT 08/02/14
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    M    M    L    L    L    L    L    L
HTS CONSISTENCY  H    H    H    H    H    M    L    L    L    L    L    L
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
EKN CONSISTENCY  H    H    M    M    H    H    L    L    L    L    L    L
PKB CONSISTENCY  H    H    H    H    H    M    L    L    L    L    L    L
CKB CONSISTENCY  H    H    H    H    H    M    H    L    L    L    L    L

AFTER 00Z SUNDAY...
BRIEF IFR CONDITIONS POSSIBLE IN AFTERNOON AND EVENING THUNDERSTORMS
SATURDAY EVENING AND SUNDAY.

&&

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

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...TRM/50
SHORT TERM...SL
LONG TERM...SL
AVIATION...50











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