Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 180221
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
921 PM EST WED DEC 17 2014

.SYNOPSIS...
LOW LEVEL MOISTURE THINS INTO THURSDAY. HIGH PRESSURE FRIDAY.
LOW PRESSURE SYSTEM FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH THURSDAY/...
920 PM UPDATE...NO SIGNIFICANT CHANGES MADE.

PREVIOUS DISCUSSION...
AS TEMPERATURES ALOFT GET COLDER...A BIT MORE FAVORABLE FOR
LINGERING LIGHT SNOW SHOWERS AND FLURRIES OVER THE MOUNTAINS THE
REST OF THE AFTERNOON.

THERE ARE "NEVER ANY ALWAYS" IN THIS BUSINESS.  DESPITE A PATTERN
SIMILAR TO LAST WEEKEND...WITH LOW LEVEL MOISTURE TRAPPED UNDER THE
INVERSION...CONCERNED CLOUDS MAY BREAK UP SOONER...ESPECIALLY IN
SOUTHERN COUNTIES.

MODELS DO NOT SEEM TO BE HANDLING THE THINNING LOW CLOUDS ON
SATELLITE IMAGE S OF CRW THIS WEDNESDAY AFTERNOON.  THIS LEADS TO
MANY DIFFICULTIES FOR TONIGHT. CLOUDS AND THUS TEMPERATURES ARE A
MAJOR ISSUE...BUT FOR THE GENERAL PUBLIC IT IS NOT A MEMORABLE
SUBJECT. WILL LIKELY GO WITH MORE PARTIAL CLEARING IN SOUTHERN
COUNTIES AND A BIT COLDER TONIGHT IN OUR AFTERNOON UPDATE. OF
COURSE...EAST OF MOUNTAIN CRESTS...THE USUAL CLEARING IN POCAHONTAS
COUNTY TOO.

WILL KEEP IT DRY THURSDAY. THOUGH SOME MID LEVEL MOISTURE/CLOUDS
INCREASING...COULD BE DETECTED BY RADAR.  MID LEVEL TROF AXIS
APPROACHES OHIO VALLEY COUNTIES BY 00Z FRIDAY.

AS A SIDE NOTE...MADE A FACEBOOK POST TODAY ABOUT THE 25TH
ANNIVERSARY OF THE PRE CHRISTMAS COLD WAVE OF DECEMBER 1989.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A SFC LOW PRESSURE SYSTEM WILL MOVE EAST...ACROSS THE SOUTHEASTERN
STATES ON SATURDAY. AT THE UPPER LEVELS...MODELS BRING
CONSIDERABLE FORCING IN FORM OF A OPEN WAVE AT H500 AND ASSOCIATED
VORTICITY MAXIMA PASSING JUST SOUTH OF THE AREA ACROSS TN...KY AND
VA. THE INFLUENCE OF THIS SYSTEM COULD AFFECT WV SATURDAY AND
SATURDAY NIGHT WITH A WINTRY MIX PRECIPITATION. FREEZING
RAIN...SLEET...RAIN AND/OR SNOW COULD BE POSSIBLE.

THE ECMWF HAS TRENDED FURTHER SOUTH AND EAST WITH THIS
SYSTEM...WHILE THE GFS...CMC...AND ESPECIALLY THE NAM BRING
PERIODS OF PCPN IN THEIR QPF FIELDS OVER THE WV AND VA. DECIDED TO
KEEP LIKELY TO CATEGORICAL POPS WITH THIS SYSTEM PER PERSISTENCE
AMONG THE MODEL CONSENSUS. CONFIDENCE AT THIS TIME IS LOW...AND
CHANGES TO THE FORECAST MIGHT BE POSSIBLE DURING THE UPCOMING
DAYS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GRADUAL DRYING TREND SUNDAY AS LOW PRESSURE SYSTEM AND UPPER
SHORTWAVE TROUGH PUSHES OFF TO THE EAST. WARMER WEATHER WILL THEN
TAKE HOLD SUNDAY INTO MONDAY AS HEIGHTS BUILD OUT AHEAD OF NEXT
APPROACHING SYSTEM. ALTHOUGH MAINLY DRY MONDAY...COULD SEE SOME
LIGHT PRECIPITATION ACROSS PARTS OF THE MOUNTAINS AS ANOTHER LOW
MOVES NORTHEAST ALONG THE COAST. ECMWF AND GFS TAKE COMPLETELY
DIFFERENT PATHS WITH THIS LOW...BUT AT THIS POINT...LOOKS LIKE ANY
MAJOR EFFECTS WITH THIS LOW WILL REMAIN OUTSIDE OF THE AREA.

FOCUS THEN SHIFTS TO A STRONG SYSTEM ACROSS THE UPPER MID
WEST...THAT WILL SPREAD PRECIPITATION...AND A COLD FRONT BACK INTO
THE AREA LONG ABOUT TUESDAY/TUESDAY NIGHT...AND LAST INTO AT LEAST
THURSDAY...WHEN THE LOW WILL FINALLY PULL OFF TO THE NORTHEAST.
PRECIPITATION SHOULD START OUT AS MOSTLY RAIN...EXCEPT ACROSS HIGHER
TERRAIN...ON TUESDAY...BEFORE TRANSITIONING TO MOSTLY SNOW TUESDAY
NIGHT...THEN AGAIN WEDNESDAY NIGHT. ALONG WITH THE WINTRY
PRECIPITATION...GUSTY WINDS ARE EXPECTED ON WEDNESDAY INTO THURSDAY.
WINTER WEATHER HEADLINES MAY BE NECESSARY DURING THIS PERIOD.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
LOW LEVEL MOISTURE ERODING ACROSS THE SOUTH AS HIGH PRESSURE
NOSES IN. SOME QUESTION ON JUST HOW FAR NORTH THIS DRIER AIR WILL
MAKE IT...SO SOME UNCERTAINTY ON WHEN WE MAY BREAK OUT OF MVFR AT
SITES SUCH AS HTS AND CRW. MODELS SHOW LOW LEVEL MOISTURE HANGING
TOUGH AT HTS AND CRW...BUT THEY SEEM TO BE TOO PESSIMISTIC BASED
ON WHATS HAPPENING IN EASTERN KY. NORTHWEST FLOW REMAINS...SO MAY
ALSO FILL BACK IN AT BKW OVERNIGHT. OTHERWISE EXPECT MVFR TO
REMAIN THROUGH THE NIGHT ACROSS THE NORTH...AND MUCH OF TOMORROW
AT CKB AND EKN. WINDS WILL GENERALLY REMAIN FAIRLY LIGHT OUT OF
THE W AND NW THROUGH THE TAF PERIOD.

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

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: MORE CLEARING COULD OCCUR THAN EXPECTED TONIGHT
ACROSS SOUTHERN CWA.

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                                                       THU 12/18/14
UTC 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
EST 1HRLY       21   22   23   00   01   02   03   04   05   06   07   08
CRW CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    M
HTS CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    M
BKW CONSISTENCY  M    M    M    M    M    M    M    H    M    M    M    M
EKN CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    M
PKB CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    M
CKB CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    M

AFTER 00Z FRIDAY...
IFR POSSIBLE IN WINTRY MIX SATURDAY INTO SUNDAY.

&&

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

&&

$$
SYNOPSIS...KTB/ARJ/SL
NEAR TERM...KTB/MZ
SHORT TERM...ARJ
LONG TERM...SL
AVIATION...MZ








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