Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 090948
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
448 AM EST TUE FEB 9 2016

.SYNOPSIS...
COLD AND UNSETTLED TODAY THROUGH WEDNESDAY UNDER A LARGE MID AND
UPPER LEVEL LOW...WITH ROUNDS OF SNOW SHOWERS. ANOTHER ARCTIC
FRONT BRINGS SNOW SHOWERS TO START THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
445 AM UPDATE...
GIVEN OBSERVED SNOWFALL AND NEW FCST AMOUNTS REMOVING SOME LOW
NEAR TERM MODELS...NEW SNOW TOTALS NECESSITATE UPGRADE TO WARNING
FOR MIDDLE OHIO VALLEY COUNTIES...IN CONCERT WITH THAT ALREADY UP
UP STREAM...AND GOING UNTIL 6 PM TODAY. REST SAME.

PREV DISCN...
IMPRESSIVE EASTERN U.S. TROUGH OVER THE AREA EARLY THIS MORNING
WITH H5 HEIGHT ANOMALIES 3 SD BELOW NORMAL OVER THE SERN U.S.
INCLUDING THE FL PANHANDLE AND NRN GULF COAST. H85 TEMPERATURE
ANOMALIES GET TO 3 SD BELOW NORMAL IN THAT AREA TONIGHT. AN ALMOST
EQUALLY IMPRESSIVE WRN U.S. RIDGE WAS IN PLACE WITH HEIGHTS 2.5 SD
ABOVE NORMAL OVER THE NRN ROCKIES.

THIS SPELLS A COLD FCST TODAY AND TONIGHT WITH NUMEROUS SNOW
SHOWERS AROUND BENEATH THE DEEP UPPER LEVEL LOW. THE ARCTIC FRONT
WAS JUST MOVING NEWD THROUGH CENTRAL WV EARLY THIS MORNING...AND
SHOULD GET THROUGH THE REMAINDER OF THE AREA FIRST THING THIS
MORNING. GUSTY SNOW SHOWERS ACCOMPANY THE FRONT. THE WET SNOW
LAST EVENING AND OVERNIGHT...AND THE SHARPLY LOWER TEMPERATURES
EARLY THIS MORNING...WILL LEAD TO SLICK ROADS BENEATH THE SNOW
THIS MORNING...PARTICULARLY WHERE NOT TREATED OR PRE-TREATED.

THE OTHER NOTABLE FEATURE UNDER THE NOSE EARLY THIS MORNING IS A
BAND OF SNOW ACROSS SRN OHIO ASSOCIATED WITH AN UPPER LEVEL S/W
TROUGH PIVOTING AROUND AN UPPER LEVEL LOW OVER N-CENTRAL OHIO.
ENHANCED BY REVERSE WARM ADVECTION FROM THE N...THIS BAND MAY
PERSIST THROUGH MUCH OF THE DAY TODAY...CONTINUING TO PIVOT FOR A
TIME BEFORE FINALLY DRIFTING E OF THE OHIO RIVER.

OTHERWISE SNOW SHOWERS WILL BE MOST PERSISTENT IN AND JUST W OF
THE MOUNTAINS GIVEN UPSLOPE FLOW...BUT DIURNAL HEATING BENEATH THE
UPPER LOW WILL MAKE FOR AUTO CONVECTIVE SOUNDINGS IN THE LOWER
LEVELS WHICH WILL ENHANCE SNOW SHOWERS ACROSS THE LOWLANDS AS
WELL.

USING A BLEND OF SHORT AND NEAR TERM MODELS TODAY AND SHORT TERM
MODELS TONIGHT...OROGRAPHIC LIFT AND SNOW RATIOS DERIVED FROM
DENDRITIC GROWTH...SNOW AMOUNTS STILL FALL TWO TO FIVE INCHES
BELOW WARNING CRITERIA...THE LOW TWO INCH DIFFERENCE BEING IN AND
NEAR OHIO...ASSOCIATED WITH THE BAND OF SNOW PIVOTING ABOUT THAT
AREA TODAY. WILL NEED TO KEEP A KEEN EYE ON THAT SITUATION FOR
POSSIBLE UPGRADE TO A WARNING AS IS ALREADY IN EFFECT UPSTREAM
UNTIL NOON TODAY.

ALSO USED A BLEND OF SHORT AND NEAR TERM MODELS FOR TEMPERATURES
TODAY...AND THEN BLENDED IN BIAS CORRECTED VERSIONS OF THE MAV
AND NAM FOR LOWS TONIGHT...SLIGHTLY LOWER VALUES ALL AROUND
COMPARED WITH PREVIOUS. ALSO HAVE LOWER DEW POINTS...PARTICULARLY
IN A DRY SWATH ACROSS ERN KY...SRN WV AND SW VA...FURTHER
DIFFERENTIATING THE COVERAGE OF SNOW SHOWERS THERE
TODAY...COMPARED WITH AREAS TO THE N.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
BROAD UPPER LEVEL TROUGH WILL CONTINUE TO AFFECT THE LOCAL AREA
WEDNESDAY. THE LOW STARTS TO LIFT OUT OF THE AREA WED NT AND THU.

A SERIES OF VORTICITY LOBES WILL ROTATE AROUND THE PERIPHERY OF THE
TROUGH TO KEEP SOME FORCING FOR SNOW SHOWERS WEDNESDAY THROUGH
THURSDAY. WESTERLY FLOW WEDNESDAY VEERS FROM THE NORTHWEST THURSDAY.

NORTHWEST FLOW WILL SET THE PLUME OF MOISTURE FROM LAKE MICHIGAN
RIGHT TOWARDS NORTH OF OUR AREA THURSDAY. IN ADDITION...NORTHWEST
FLOW WILL PRODUCE UPSLOPE SNOW SHOWERS IN AND NEAR THE MOUNTAINS
WEDNESDAY NIGHT INTO THURSDAY.

CODED FROM ONE TO 2.4 INCHES OF SNOW RANGING FROM SOUTHEAST
OH...EAST INTO THE EASTERN MOUNTAINS BY WEDNESDAY NIGHT. AN
ADDITIONAL INCH OR SO EXPECTED OVER THE NORTHEAST MOUNTAINS
THURSDAY.

ANOTHER VORTICITY LOBE CROSSES THE AREA FRIDAY UNDER NORTHWEST FLOW
ENHANCING SNOW OVER THE LOWLANDS...AND UPSLOPE SNOW OVER THE
EASTERN MOUNTAINS FRIDAY INTO THE WEEKEND.

USED THE SUPERBLEND FOR TEMPERATURES THROUGH THE PERIOD.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
SOME LINGERING SNOW SHOWERS ACROSS THE NORTHERN MOUNTAINOUS COUNTIES
TO START THE PERIOD. THIS IS DUE TO NW FLOW ALOFT. HOWEVER...A
SURFACE HIGH PRESSURE IS NOSING IN SO IT WILL BE A TIGHTROPE WALK
BETWEEN NORTHWEST FLOW AND DEPARTING MOISTURE. SOME UNCERTAINTY ON
POPS THIS WEEKEND...AS ECMWF SLIDES A SURFACE LOW TO OUR NORTH
DRIVING A COLD FRONT THROUGH. HOWEVER...THE GFS IS MUSH LESS ROBUST
WITH THIS SYSTEM...WITH A WEAKER FRONT AND LESS MOISTURE. STAYED IN
CHANCE POPS FOR NOW.

EITHER WAY...REINFORCING SHOT OF COLD AIR ARRIVES WITH THIS FRONT
SETTING UP A VERY CHILLY WEEKEND. STILL BREEZY DURING THIS TIME AS
THE NEXT HIGH PRESSURE DOES NOT NOSE IN UNTIL DURING THE DAY SUNDAY.
WILL MENTION POTENTIAL FOR WIND CHILL ADVISORY IN THE HWO. MOST
WIDESPREAD ISSUE LOOKS TO BE SATURDAY NIGHT...BUT SHOULD HIGH ARRIVE
SOONER THAN FORECAST...WIND COULD SHUT DOWN EARLY.

ANOTHER SYSTEM LOOKS TO IMPACT THE END OF THE PERIOD...BUT WITH
FAIRLY DRASTIC DIFFERENCES IN THE MODELS STUCK CLOSE TO WPC FOR NOW.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
A SOMEWHAT LOW CONFIDENCE FCST DURING THE 24 HOUR TAF PERIOD DUE
TO THE VARIABILITY OF CONDITIONS WITH NUMEROUS SNOW SHOWERS
ABOUT.

A VERY COLD AIR MASS OVERTAKES THE AREA OVERNIGHT...AS AN UPPER
LEVEL LOW SETTLES IN OVER THE UPPER OHIO VALLEY. THIS WILL KEEP
SNOW SHOWERS...AND ASSOCIATED IFR CONDITIONS...MOST FREQUENT
ACROSS THE MIDDLE OHIO VALLEY AND NRN WV ALTHOUGH...BECAUSE THIS
IS AN UPSLOPE PATTERN...FREQUENT MVFR CONDITIONS WITH IFR AT TIMES
CAN BE EXPECTED DOWN THE WV MOUNTAINS. THIS LEAVES ERN KY AND SRN
WV WITH VFR VSBY MUCH OF THE TIME...BUT ANY SNOW SHOWER OR BAND
CAN BRING A BRIEF PERIOD OF IFR. EVEN THERE...MVFR CIGS WILL BE
PERSISTENT...PERHAPS LIFTING TO MVFR AT TIMES TUE AFTERNOON.

SFC FLOW WILL BE MAINLY FROM THE W...AND BE GUSTY AT
TIMES...MAINLY DURING THE DAY ON TUE. HOWEVER...WINDS WERE GUSTY
AT HTS AS OF 06Z...JUST BEHIND THE ARCTIC FRONT...AND BRIEF GUSTY
WINDS ARE LIKELY TO PROGRESS NEWD ACROSS WV THROUGH EARLY TUE
MORNING...AS THE ARCTIC FRONT MOVES FROM SW TO NE THROUGH THE
STATE. FLOW ALOFT WILL BE LIGHT TO MODERATE W.

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

FORECAST CONFIDENCE...LOW

ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR WILL VARY IN SNOW
SHOWERS OVERNIGHT AND ESPECIALLY ON TUE.

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               TUE 02/09/16
UTC 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
EST 1HRLY       05   06   07   08   09   10   11   12   13   14   15   16
CRW CONSISTENCY  M    M    M    M    M    M    M    M    M    M    M    M
HTS CONSISTENCY  M    M    M    M    M    M    M    H    H    H    H    M
BKW CONSISTENCY  M    L    L    L    M    M    M    M    M    M    M    M
EKN CONSISTENCY  L    L    L    L    L    L    L    L    L    L    L    L
PKB CONSISTENCY  L    L    L    L    L    M    M    M    M    M    M    M
CKB CONSISTENCY  L    L    L    L    L    L    L    L    L    L    L    L

AFTER 12Z WEDNESDAY...
PERIODS OF IFR CONDITIONS IN SNOW SHOWERS ALL THE WAY THROUGH
WEDNESDAY NIGHT...ESPECIALLY NORTH AND EAST PORTIONS OF AREA.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR
     WVZ005>008-011-013>020-024>040-046-047.
     WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
     WEDNESDAY FOR WVZ009-010.
     WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR WVZ009-
     010.
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR OHZ083-
     086-087.
     WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
     WEDNESDAY FOR OHZ066-067-075-076-084-085.
     WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR OHZ066-
     067-075-076-084-085.
KY...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR
     KYZ101>103-105.
VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR VAZ003-
     004.

&&

$$
SYNOPSIS...ARJ/TRM
NEAR TERM...TRM
SHORT TERM...ARJ
LONG TERM...MZ
AVIATION...TRM


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