Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 230720
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
305 AM EDT WED APR 23 2014

.SYNOPSIS...
HIGH PRESSURE AND COOLER WEDNESDAY. DRY WARM FRONT
THURSDAY. A WEAK COLD FRONT CROSSES THE AREA FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
NORTHWEST FLOW CREATING A STRATUS DECK OVER THE NORTHERN COUNTIES
THIS MORNING. MODELS HANDLE THIS MOISTURE CONSIDERABLY DIFFERENTLY
TODAY WHEN MIXING STARTS OCCURRING. RUC SHOWS IT QUICKLY MIXING OUT
WHILE THE NAM AND GFS HOLD ONTO CUMULUS WELL INTO CENTRAL WV. WENT
MORE TOWARD THE RUC FOR NOW...BUT CONFIDENCE IS LOW.

WITH A NORTHWEST FLOW CONTINUING TODAY...WENT TOWARD THE COOLER MOS
GUIDANCE FOR HIGHS.

WINDS SHOULD DECOUPLE TONIGHT...ALLOWING FOR SOME GOOD RADIATION.
BIG QUESTION IS HOW QUICKLY CLOUDS FROM THE WARM FRONT PUSH INTO THE
AREA. THIS BECOMES EXTRA IMPORTANT DUE TO THE POSSIBILITY OF
FREEZING TEMPERATURES IF THERE IS ENOUGH CLOUD FREE TIME AFTER WINDS
LAY DOWN. WILL GO WITH A FREEZE WATCH ACROSS THE NORTHERN COUNTIES
WHERE COLDEST TEMPERATURES ARE EXPECTED...BUT OUTLYING AREAS JUST
SOUTH OF THE FREEZE WATCH ARE NOT NECESSARILY SAFE...DEPENDING ON
CLOUD TIMING.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MODELS IN GENERAL AGREEMENT THIS PERIOD.

HIGH PRESSURE WILL BE LOCATED OVER THE AREA EARLY THURSDAY.
HOWEVER...HIGH WILL SLIDE EAST...ALLOWING A WARM FRONT TO
DEVELOP/PUSH INTO THE AREA BY THURSDAY AFTERNOON.  THIS FRONT WILL
PUSH NORTH THURSDAY NIGHT.

LATEST GUIDANCE ACTUALLY INDICATES AIRMASS WILL BE DRIER THAN OUR
PREVIOUS FORECAST INDICATED.  APPEARS THIS IS THE RESULT OF A SLOWER
MOVEMENT OF THE WARM FRONT.  HAVE TWEAKED DEWPOINTS DOWN QUITE A
BIT...ESPECIALLY ACROSS SOUTHERN PORTIONS OF THE REGION. WITH
AIRMASS REMAINING DRY INVOF THIS FEATURE...ONLY EXPECT AN INCREASE
IN CLOUDS.

A COLD FRONT IS THEN PROGGED TO PUSH EAST ACROSS THE REGION LATE
THURSDAY NIGHT INTO FRIDAY.  LATEST GUIDANCE IS A LITTLE SLOWER WITH
THE FRONT...AND HAVE TWEAKED POP AND WEATHER GRIDS TO REFLECT THIS
TREND.  NOT MUCH...IF ANY...INSTABILITY ALONG/AHEAD OF FRONT.  BUT
NAM DOES SHOW A LITTLE.  WITH PREVIOUS FORECAST INDICATING SLIGHT
CHANCE THUNDER...HAVE DECIDED TO KEEP IT IN PLACE.

WEAK HIGH PRESSURE SHOULD NOSE IN FROM THE SOUTHWEST FRIDAY
AFTERNOON...BRINGING PRECIP CHANCES TO END.

MODELS HAVE BEEN CONSISTENT PUSHING A WEAK COLD FRONT SOUTHEAST LATE
FRIDAY NIGHT INTO SATURDAY.  HAVE MAINTAINED LOW POPS WITH THIS
FEATURE.

LATEST MAV NUMBERS FOR HIGHS ON THURSDAY WERE CLOSE TO PREVIOUS
FORECAST NUMBERS...WITH THE MET NUMBERS LOWER.  MET NUMBERS APPEAR
TO BE ON THE COOL SIDE...SO HAVE LEANED TOWARDS THE MAV NUMBERS.

STILL NOT SURE ABOUT LOWS THURSDAY NIGHT.  WITH SOUTHERLY WINDS AND
INCREASING LOW-LEVEL MOISTURE...EXPECT TEMPS WILL REMAIN UP AND HAVE
AGAIN LEANED TOWARD MAV NUMBERS.  BUT WOULD NOT BE TOO SURPRISED TO
SEE LOWS SLIP BELOW OUR FORECASTED VALUES.

CURRENT THINKING IS THAT MAV NUMBERS ALSO LOOK BEST FOR HIGHS ON
FRIDAY...AS LITTLE IN THE WAY OF COOLING IS INDICATED BEHIND THE
FRONT.

MEX NUMBERS WERE USED TO TWEAK PREVIOUS NUMBERS FOR LOWS FRIDAY
NIGHT AND HIGHS ON SATURDAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
THE FRONT COULD STALL SOUTH OF THE AREA DURING THE WEEKEND BEFORE
LIFTING NORTH AS A WARM FRONT SUNDAY AND MONDAY FOR ADDITIONAL PCPN
MAINLY EXTREME SOUTHERN WV.

USED HPC GUIDE FOR TEMPERATURES AND DEWPOINTS WITH FEW TWEAKS DOWN
ON HIGHS THROUGH THE PERIODS.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
A STRATUS DECK OVER NORTHEASTERN WV...SCATTERING WESTWARD ACROSS
NORTHERN WV AND EAST CENTRAL OHIO...MAY CAUSE SOME MVFR CONDITIONS
THIS MORNING. THIS DECK SHOULD TURN INTO A CUMULUS DECK AND
DISSIPATE TODAY AS THE SUN MIXES THE ATMOSPHERE. VFR CONDITIONS CAN
THEN BE EXPECTED.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...

FORECAST CONFIDENCE: HIGH.

ALTERNATE SCENARIOS: EXTENT OF THE STRATUS DECK IN THE NORTH 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                              WED 04/23/14
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
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    L    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 06Z THURSDAY...
NO IFR CONDITIONS EXPECTED.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
     WVZ008>011-016>020-027>032.
OH...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
     OHZ066-067-075-076-085.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...JSH/RPY
NEAR TERM...RPY
SHORT TERM...JSH
LONG TERM...ARJ
AVIATION...RPY












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