Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 252000 CCA
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
258 PM EST WED FEB 25 2015

.SYNOPSIS...
LOW PRESSURE SYSTEM PASSES TO OUR SOUTHEAST LATE TONIGHT. COLD FRONT
WITH SNOW SHOWERS LATE THURSDAY/THURSDAY NIGHT. DRY ARCTIC HIGH
PRESSURE FRIDAY. CLIPPER LATE IN THE WEEKEND.

&&

.NEAR TERM /THROUGH THURSDAY/...
QUICK HITTING STORM BRUSHES CWA OVERNIGHT.  BEST SUPPORT ALOFT FROM
COUPLED 250 MB JET IS AT 00Z TONIGHT...HELPING TO QUICKLY MOISTEN
THE COLUMN TO OUR SOUTH AND THUS THICKEN THE CLOUDS OVER SOUTHERN
COUNTIES.  OF COURSE...EXACTLY HOW FAR NORTH THE FLAKES REACH THE
GROUND IS ALWAYS A CHALLENGE.  DURATION OF THE DEEPER MOISTURE IS
ONLY 6 TO 12 HOURS...AND SOUNDINGS NOT THE MOST FAVORABLE...A BIT ON
THE MILD SIDE...FOR BEST CRYSTAL GROWTH. WILL HAVE THE MAIN POP
GRADIENT RUNNING FROM NEAR LOUISA NORTHEAST TO CHARLESTON AND
PHILIPPI...WITH MUCH HIGHER TO THE E-SE...LOWER TO THE W-NW.  AS
CEILINGS CRASH OVER THE SOUTHERN MOUNTAINS NEAR BKW IN THE
SNOW...THE WEAK SE FLOW MAY HOLD CLOUDS HIGHER VCNTY CRW.

SO ALL IN ALL...STILL NO WARNINGS. WILL EXPAND OUR EXISTING WINTER
WEATHER ADVISORY JUST A BIT...MAINLY FOR 1 TO 3 INCHES OF SNOW
OVERNIGHT INTO THURSDAY MORNING. THE MILDER BOUNDARY LAYER
TEMPERATURES MAY RESULT IN THE MORE TYPICAL SNOW VARIATION BETWEEN
RIVER VALLEY AND HIGH TERRAIN ACROSS THESE SOUTHERN COAL FIELDS.

CONFIDENCE LOWERS ON HOW THE DAY UNFOLDS ON THURSDAY.  WITH THINKING
A LOT OF CLOUDS WILL LINGER OVER THE MOUNTAINS...AFTER SATURATING
OVERNIGHT.  STILL TRYING TO PAINT A BREAK IN POPS OVER THE OHIO
VALLEY THURSDAY MORNING...BEFORE INCREASING AGAIN THURSDAY AFTERNOON
WITH THE WEAKENING NORTHERN STREAM FEATURE.

SO NOT FORESEE MUCH OF A TEMPERATURE DROP OVERNIGHT WITH THE
PREVIOUSLY MENTIONED THICKENING CLOUDS.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE BUILDS ACROSS THE OH VALLEY...WV AND PA SATURDAY.
HOWEVER...MODELS SUGGEST LINGERING MOISTURE WITHIN THE DENDRITE
GROWTH ZONE ACROSS CENTRAL WV AND EAST THURSDAY NIGHT. THIS SUGGEST
A CONTINUATION OF LIGHT SNOW SHOWERS THURSDAY NIGHT.  AS THE FLOW
TURNS NORTHWEST...LINGERING MOISTURE COULD STILL PRODUCE UPSLOPE
SNOW MAINLY OVER OUR NORTHEAST MOUNTAINS INTO FRIDAY. INCREASED POPS
HIGHER THAN 50 PERCENT...OR LIKELIES TO ACCOUNT FOR MINOR SNOW
ACCUMULATIONS OVER PORTIONS OF THE LOWLANDS AND EASTERN MOUNTAINS
THROUGH FRIDAY. ALL PCPN SHOULD MOVE OUT BY FRIDAY NIGHT.

WEATHER IMPROVES FRIDAY INTO FRIDAY NIGHT WITH COLDER AIR RUSHING IN
AS SEEN ON MODELS H850 TEMPERATURES REACHING MINUS 17C. THIS COULD
BRING A NON DIURNAL TREND IN TEMPERATURES FRIDAY WITH HIGHS STAYING
AROUND 20F RANGING INTO THE SINGLE DIGITS OVER THE HIGHEST PEAKS.
AND LOWS FRIDAY NIGHT INTO THE LOWER SINGLE DIGITS EXTREME SOUTH
RANGING INTO AROUND ZERO AND FEW DEGREES BELOW FURTHER NORTH.

USED THE BIAS CORRECTED ALL BLEND FOR TEMPERATURES THROUGH THE
PERIOD.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE TO START THE PERIOD. HOWEVER...CLIPPER TYPE SYSTEM
WILL MOVE THROUGH AREA SUNDAY THROUGH MONDAY...FOLLOWED BY ANOTHER
LOW THAT WILL MOVE NORTHEAST OUT OF THE GULF TOWARDS THE REGION MID
WEEK. FIRST CLIPPER SYSTEM WILL SEE MAINLY RAIN TO START...BUT
TRANSITION OVER TO LIGHT SNOW SUNDAY NIGHT AS COLDER AIR RUSHES IN
BEHIND THE FRONT.

STILL LOOKING LIKE THE MID WEEK LOW WILL MOVE ACROSS OUR NORTH
THROUGH OHIO. WARM AIR AND MOISTURE WILL SURGE INTO THE REGION OUT
AHEAD OF THE LOW...WITH STRONG SOUTHWESTERLY FLOW DEVELOPING...AND
PW VALUES RISING TO WELL ABOVE NORMAL FOR THIS TIME OF YEAR. THIS
WILL BE A MAINLY RAIN SYSTEM...WITH THE POSSIBILITY RAIN COULD BE
HEAVY AT TIMES. BASED ON THE PATH OF THE LOW...COULD SEE A BRIEF DRY
SLOT DEVELOP ACROSS PARTS OF THE WV LOWLANDS...BUT TOO EARLY TO
FIGURE THAT IN AT THIS POINT. WITH THE RAIN...COULD BE SOME
LOCALIZED WATER ISSUES NEXT WEEK. WILL CONTINUE TO LEAVE OUT OF THE
HWO AT THIS TIME...AS IT IS SEVERAL DAYS UNTIL THE EVENT...AND
ANYTHING COULD HAPPEN IN THE MODEL RUNS UNTIL THEN...THUS CHANGING
THE FORECAST.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
VFR INTO THE EVENING.  THICKENING MID LEVEL CLOUDS AT 8 TO 12 THSD
FT AGL FROM SOUTHWEST TO NORTHEAST 00Z TO 06Z...WITH LIGHT SNOW
DEVELOPING LNP TO BKW CORRIDOR DURING THE 03Z TO 06Z TIME FRAME.

DETERIORATING CONDITIONS MOSTLY OVER MOUNTAIN COUNTIES WITH WEAK SE
FLOW. TRIED TO HOLD CEILINGS HIGHER VCNTY OF CRW DESPITE FORECASTING
LIGHT SNOW DURING THE 06Z TO 12Z TIME FRAME.

CONFIDENCE LOWERS IN WAKE OF THE DEEPER MOISTURE FOR THE 12Z TO 18Z
FRAME ON THURSDAY. TRIED TO HOLD ONTO SOME LOW CEILINGS AND SOME
3 TO 5 MILES IN FOG/LINGERING LIGHT SNOW OVER THE MOUNTAINS IN WAKE
OF THE MAIN SNOW BAND.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING OF SNOW REACHING THE GROUND MAY
VARY..AND HOW FAR WEST/NORTHWEST IT REACHES THE GROUND.


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       20   21   22   23   00   01   02   03   04   05   06   07
EST 1HRLY       15   16   17   18   19   20   21   22   23   00   01   02
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    M
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    M
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 18Z THURSDAY...
IFR POSSIBLE IN SNOW SHOWERS MAINLY OVER WV MOUNTAIN COUNTIES
INTO THURSDAY NIGHT.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 9 AM EST
     THURSDAY FOR WVZ033>036.
     WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
     THURSDAY FOR WVZ024-025.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 7 AM EST
     THURSDAY FOR VAZ003-004.

&&

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










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