Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 181346
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
946 AM EDT SAT APR 18 2015

.SYNOPSIS...
WEAK HIGH PRESSURE FADES TODAY.  WARM FRONT CROSSES THIS EVENING. A
COLD FRONT CROSSING MONDAY HERALDS A PERIOD OF COOLER WEATHER...AS
IT IS FOLLOWED BY ANOTHER WEDNESDAY NIGHT OR THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
945AM UPDATE...
ADDED SLIGHT CHANCE OF SHOWERS TO THE EXTREME FRINGE OF THE CWA
THIS AFTERNOON.

PREVIOUS DISCUSSION...
UPPER LEVEL RIDGE CROSSES TODAY AND SHIFTS E OF THE AREA
TONIGHT...AS NRN AND SRN UPPER LEVEL S/W TROUGHS APPROACH FROM THE
W. THE NRN STREAM ONE DIGS INTO ND BY 12Z SUN WHILE THE SRN STREAM
FEATURE...A CLOSED LOW COMING OUT OF THE FOUR CORNERS REGION EARLY
THIS MORNING...OPENS UP AS IT TRAVERSES THE SRN PLAINS TONIGHT.
SFC LOWS ARE FOUND E OF EACH UPPER FEATURE...BUT A WARM WAVE LOW
ALSO FORMS OUT AHEAD OF THE SRN STREAM FEATURE OVER THE DEEP S
LATER TODAY AND REACHES THE MID MISSISSIPPI VALLEY BY 12Z SUN...IN
RESPONSE TO A LEAD S/W TROUGH AXIS AHEAD OF THE MAIN SRN STREAM
TROUGH.

AT THE SFC...WEAK HIGH PRESSURE OVER THE CWA THIS MORNING FADES AS A
STRONGER HIGH BUILDS SEWD INTO ERN CANADA...AND DRIVES A BACK DOOR
COLD FRONT DOWN THE E COAST.  IT...AND THE WARM WAVE APPROACHING
FROM THE W...INCREASES THE SE GRADIENT OVER THE CWA OVERNIGHT
TONIGHT.

SOMEWHAT DRIER AIR MANAGED TO FILTER DOWN THE MIDDLE OHIO VALLEY BUT
DEW POINTS REMAIN HIGH IN AND NEAR THE CENTRAL APPALACHIANS.  THIS
RESULTED IN DENSE VALLEY FOG E OF THE OHIO RIVER EARLY THIS
MORNING...WHICH MAY LIFT INTO STRATUS AND THEN MORNING CU.  THIS
SHOULD THEN MIX OUT...BUT EXPECT ELEVATED HEAT SOURCE CU TO FORM
OVER THE MOUNTAINS THIS AFTERNOON.  DRY MID LEVELS SHOULD PREVENT
ANYTHING FARTHER DESPITE WEAK CONVERGENCE OVER THE MOUNTAINS...BUT
THE CU MAY TOWER A LITTLE OVER THE SRN MOUNTAINS.

INCREASING CLOUD AND PRESSURE GRADIENT SHOULD PRECLUDE FOG FORMATION
TONIGHT.  MODELS ARE IN GOOD AGREEMENT ON PRECIPITATION REACHING FAR
SRN PORTIONS OF THE CWA BY 12Z SUN...INCREASED POPS TO LIKELY FOR SW
VA AND CHANCE ALONG THE TUG FORK...AS A WARM FRONT EXTENDING ESEWD
FROM THE WARM WAVE...APPROACHES FROM THE S.

CLUSTERED GUIDANCE SUGGESTED SLIGHTLY HIGHER HIGHS FOR TODAY WHILE
BLENDING IN OF CLUSTERED BIAS CORRECTED GUIDANCE YIELDED HIGHER LOWS
FOR TONIGHT AS THE CLOUD AND WIND INCREASE.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
ACTIVE WEATHER IN THE SHORT TERM PERIOD. GOOD SOUTHEASTERLY FLOW
WILL DEVELOP ACROSS THE AREA ON SUNDAY AS A SURFACE LOW AND
NEGATIVELY TILTED UPPER TROUGH LIFT NORTHEAST ACROSS THE MIDWEST.
EXPECTING RATHER GUSTY WINDS TO DEVELOP ON SUNDAY...AS PRESSURE
GRADIENT TIGHTENS...AND LLJ STRENGTHENS ACROSS THE REGION...WITH
HIGHER GUSTS EXPECTED ACROSS THE MOUNTAINOUS COUNTIES. STILL AT THIS
POINT NOT TOO WORRIED ABOUT FLOODING ISSUES...ALTHOUGH THIS WILL BE
A RATHER DECENT SOAKER SUNDAY INTO MONDAY...PARTICULARLY ACROSS THE
MOUNTAINOUS COUNTIES IN THE SOUTHEASTERLY UPSLOPE FLOW ON
SUNDAY...AND AS A SECONDARY WAVE OF LOW PRESSURE RIDES NORTHEAST
ACROSS THE MOUNTAINS.

SURFACE COLD FRONT...AND UPPER WAVE WILL THEN MOVE THROUGH THE
REGION ON MONDAY...FOR ADDITIONAL ROUNDS OF SHOWERS AND
THUNDERSTORMS. THERE IS THE POSSIBILITY OF A STRONG STORM MAINLY
ACROSS THE SOUTH AND EAST...BUT THIS STILL REMAINS RATHER UNCERTAIN.

FOR TEMPERATURES ON SUNDAY...LOWERED SLIGHTLY FROM PREVIOUS FORECAST
DUE TO EXPECTED CLOUD COVER AND RAIN...BUT DID KEEP THE WV LOWLANDS
WARMER DUE TO THE SOUTHEASTERLY DOWNSLOPING FLOW.

COOLER AND UNSETTLED WEATHER THEN TAKES HOLD FOR MID WEEK AS UPPER
LOW LINGERS ACROSS GREAT LAKES REGION.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
COLD FRONT WILL BE EAST OF THE CWA TO START THE LONG TERM...AND HAVE
DECREASING POPS MONDAY NIGHT. SLOW MOVING UPPER LEVEL LOW PASSES TO
OUR NORTH THROUGH THE WEEK WITH SEVERAL IMPULSES IN THE WEST TO
NORTHWESTERLY FLOW...AND HAVE SOME PERIODS OF CHANCE POPS. MODELS
ALSO SHOWING A COLD FRONT WEDNESDAY INTO THURSDAY. WITH SOME TIMING
DIFFERENCES...BLENDED IN WPC GUIDANCE.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
DENSE FOG CKB AND EKN WILL BURN OFF FIRST HOUR...LIFTING BRIEFLY
INTO STRATUS FRACTUS.  OTHERWISE NOT MUCH MORNING CU EXPECTED...BUT
CU WILL FORM OVER THE HIGHER TERRAIN THIS AFTERNOON.

CLOUDS WILL INCREASE AND THICKEN TONIGHT AS A WARM FRONT APPROACHES
FROM THE S...AND LOWER TO AROUND 5 KFT BY DAWN SUNDAY.  BKW WILL
LIKELY PICK UP AN MVFR STRATOCU DECK ON STRENGTHENING SE FLOW
OVERNIGHT.  RAIN IS LIKELY TO BE CLOSE BY TO THE S BY DAWN SUNDAY.

LIGHT N TO NE SFC FLOW TODAY WILL BECOME LIGHT E TO SE
TONIGHT...FRESHENING A BIT LATE...BECOMING GUSTY ON THE HIGHER
RIDGES INCLUDING BKW.  LIGHT N FLOW ALOFT WILL BECOME LIGHT NE BY
THIS AFTERNOON AND THEN LIGHT SE TONIGHT...STRENGTHENING TO MODERATE
SE BY DAWN SUNDAY.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...

FORECAST CONFIDENCE: HIGH.

ALTERNATE SCENARIOS: TIMING OF LOSS OF IFR CKB AND EKN FIRST THING
THIS MORNING COULD VARY.  TIMING AND HEIGHT OF STRATOCU CIGS AT BKW
COULD VARY OVERNIGHT TONIGHT.

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       14   15   16   17   18   19   20   21   22   23   00   01
EDT 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
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 12Z SUNDAY...
IFR POSSIBLE IN MOSTLY SHOWERS SUNDAY AFTERNOON INTO SUNDAY
NIGHT...AND SHOWERS OR THUNDERSTORMS MONDAY INTO MONDAY EVENING.

&&

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

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...TRM/26
SHORT TERM...SL
LONG TERM...MZ
AVIATION...TRM








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