Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 312349
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
749 PM EDT THU JUL 31 2014

.SYNOPSIS...
UPPER LEVEL DISTURBANCES CROSS THE CENTRAL APPALACHIANS TONIGHT AND
FRIDAY.  A NEW UPPER LEVEL TROUGH SETTLES OVER THE MIDDLE OHIO
VALLEY THIS WEEKEND...AND THEN PULLS OUT EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
730 PM UPDATE...
THE FEW SHOWERS ACROSS THE NORTHWEST ZONES THIS AFTERNOON AND
EARLIER THIS EVENING HAVE DISSIPATED AS EXPECTED. OVERALL FORECAST
IS ON TRACK...BUT ADJUSTED POPS OVER THE FAR SOUTHERN ZONES TO
REFLECT CURRENT RADAR TRENDS/THINKING...AS SOME SHOWERS AND A FEW
LIGHTNING STRIKES BRUSH THE VA COUNTIES NORTHEASTWARD UP TOWARDS
THE RALEIGH COUNTY AREA.

PREVIOUS DISCUSSION...
NOTED A FEW SHOWERS STARTING TO POP UP OVER THE MIDDLE OHIO
VALLEY...WHERE THE CU FIELD IS MOST STOUT. HAVE ACCOUNTED FOR
ISOLATED CONVECTION THIS AFTERNOON...DYING OFF EARLY RELATIVE TO
SUNSET.

OTHERWISE MAIN FEATURE THIS PD IS A PAIR OF SRN STREAM S/W FEATURES
THAT MOVE NE ACROSS AN EVER INCREASING SE PORTION OF THE FCST AREA
OVERNIGHT INTO FRI.  WV IMAGERY SHOWS DRY SLOT BETWEEN NRN AND SRN
STREAMS OVER THE AREA THIS MORNING ALREADY SHIFTING NWD...ALLOWING
DEEPER MOISTURE TO ENCROACH UPON SW VA AND SRN WV.  THIS SHIFT
CORRESPONDS WITH A RISING HEIGHT FIELD AS THE MAIN UPPER LOW JUST S
OF HUDSON BAY FILLS...AND THE L/W TROUGH BEGINS TO LOOSEN ITS GRIP
OVER THE ERN CONUS.

HAVE SHOWERS AND THUNDERSTORMS BECOMING INCREASINGLY LIKELY OVER THE
SERN FRINGES OF THE CST AREA BY DAWN FRI...AND OVER THE MOUNTAINS BY
MIDDAY FRI...WITH AN INCREASING CHANCE OVER THE LOWLANDS FRI
AFTERNOON.  THE WWD EXPANSION OF COVERAGE FRI AFTERNOON WILL BE
MAINLY DRIVEN BY DIURNAL HEATING.  HOWEVER...AT THE SAME
TIME...UNDER THE CLOUD SHIELD...THE STABILITY ACTUALLY INCREASES
OVER THE MOUNTAINS...SO THE CHANCE FOR THUNDER THERE ACTUALLY
WANES.  THE LAST OF THE S/W/S STARTS TO PULL AWAY TO THE E LATE FRI
AFTERNOON.

LOWS TONIGHT LOOKED LIKE A REASONABLY COMPROMISE OF THE LATEST BIAS
CORRECTED GUIDANCE WHILE AN ALL BLEND SEEMED TO PROVIDE A CONSISTENT
SOLN FOR HIGHS FRI.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
UNSETTLED WEATHER RETURNS TO THE AREA OVER THE WEEKEND. UPPER TROUGH
WITH SEVERAL DISTURBANCES MOVING THROUGH THE AREA TO CONTINUE
THROUGH THE WEEKEND. MODELS CONTINUE TO KEEP BULK OF
PRECIPITATION...DYNAMICS TO EAST OF MOUNTAINS...AND CONTINUED TO
PLAY THE TREND OF HIGHER POPS ACROSS MOUNTAINS...WITH CHANCE ACROSS
LOWLANDS. WITH AN OVERALL LIGHT FLOW PATTERN EXPECTED...SHOWERS AND
STORMS THAT DEVELOP OVER THE WEEKEND WILL BE RATHER SLOW MOVING. THE
HIGHER PW WILL EXIST TO THE EAST OF THE MOUNTAINS...SO NO MAJOR
WATER ISSUES ARE EXPECTED...HOWEVER...DUE TO THE EXPECTED SLOW
NATURE OF STORMS...REPETITIVE SLOWER MOVERS OVER ANY GIVEN AREA
COULD CAUSE SWOLLEN CREEKS AND STREAMS AND PERHAPS URBAN WATER
ISSUES.

ADDITIONAL SHORTWAVE ENERGY WILL DIG SOUTH AND EAST ACROSS THE AREA
SATURDAY NIGHT INTO SUNDAY...WITH A FRONTAL BOUNDARY PUSHING EAST
ACROSS THE AREA SUNDAY NIGHT INTO MONDAY. DRIER WEATHER BEHIND THE
FRONT FOR THE START OF NEXT WEEK.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
HIGH PRESSURE GRADUALLY BUILDING IN FROM THE WEST FOR THE START OF
NEXT WEEK...FOR A BRIEF BREAK IN MUCH OF THE PRECIPITATION.
HOWEVER...HEAT AND HUMIDITY WILL BE ON THE INCREASE THROUGHOUT NEXT
WEEK...AS SOUTHERLY FLOW INCREASES AND HEIGHTS BUILD OUT AHEAD OF AN
APPROACHING STORM SYSTEM...WHICH WILL SPREAD SHOWERS AND
THUNDERSTORMS BACK INTO THE AREA TOWARDS THE END OF THE EXTENDED
PERIOD. TEMPS LOOK LIKE THEY WILL FINALLY RISE TO NORMAL OR EVEN
ABOVE NORMAL FOR THIS TIME OF YEAR.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE EVENING HOURS.
A HEAVIER SHOWER TO THE SOUTHWEST OF BKW MAY IMPACT THAT TERMINAL
IN THE NEXT HOUR WITH PERHAPS MVFR VIS.

CIGS WILL LOWER ON SE FLOW TONIGHT IN THE SOUTHEAST MOUNTAINS...WITH
MVFR STRATOCU GETTING AS FAR NW AS BKW BY DAWN FRI AND THEN LIKELY
PERSISTING THROUGH THE BALANCE OF THE TAF PERIOD. SHOWERS AND
THUNDERSTORMS ARE LIKELY IN THE MOUNTAINS FROM NEAR DAWN FRI
THROUGH AROUND THE 18Z TIME FRAME...BEFORE BEGINNING TO TAPER FROM
SOUTHWEST TO NORTHEAST AFTER 18Z. THERE IS A CHANCE FOR SHOWERS
AND THUNDERSTORMS FURTHER WEST BY 18Z FRI. CLOUDS ASSOCIATED WITH
THE UPPER LEVEL DISTURBANCE TRIGGERING THE CONVECTION...SHOULD
PREVENT A REPEAT OF THE DENSE VALLEY FOG TONIGHT...WITH VSBYS NO
WORSE THAN MVFR EXPECTED.

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

FORECAST CONFIDENCE: MEDIUM TO HIGH.

ALTERNATE SCENARIOS: FOG OR REDUCED VSBYS LATE OVERNIGHT / EARLY
FRI MORNING MAY VARY FROM THE MVFR CURRENTLY FORECAST. UNCERTAINTY
OF EFFECTS OF SHOWERS AND THUNDERSTORMS INCREASES FRI
MORNING...ESPECIALLY IN THE MOUNTAINS.

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                                                            FRI 08/01/14
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    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    M    M    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 00Z SATURDAY...
NO SIGNIFICANT IFR CONDITIONS EXPECTED.

&&

.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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