-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 121103
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
603 AM EST THU DEC 12 2013

.SYNOPSIS...
COLD HIGH PRESSURE PRESSURE BUILDS IN TODAY AND FRIDAY. A MID
LEVEL SHORTWAVE CROSSES THE AREA FROM THE SOUTHWEST...BRINGING MIXED
PRECIPITATION FRIDAY NIGHT...TRANSITIONING TO ALL RAIN BY SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
530 AM UPDATE...
INCREASED SKY COVER AND HELD MOSTLY CLOUDY WORDING IN THE FORECAST
FOR JUST AN ADDITIONAL TWO-THREE HOURS MAINLY EAST OF THE OHIO
RIVER THIS MORNING...BUT STILL EXPECT LOW STRATUS TO EVENTUALLY
SCATTER BY THE MID-MORNING HOURS. ALSO INSERTED A FLURRIES MENTION
THIS MORNING AS WELL WITH SPORADIC OBS SUCH AS UNI AND PKB
REPORTING -SN...AND SEEING FLURRIES HERE AT RLX AROUND 5AM.

PREVIOUS DISCUSSION...
08Z SFC OBS DEPICT FRONT IS NOW EAST OF THE MOUNTAINS...WITH
SECONDARY COLD SURGE SPILLING IN QUICKLY THIS MORNING. LOCATIONS
SUCH AS ZZV AND VALENTINE OH NOW DOWN INTO THE LOWER TEENS WITH
MUCH OF CENTRAL WV LOWLANDS INTO THE MID 20S. MOSAIC RADAR IMAGERY
CONTINUING TO DEPICT LIGHT SNOW GENERALLY ACROSS NE OHIO AND SW
PENN...THE WESTERN EDGE OF WHICH CORRESPONDS NICELY WITH THE
WESTERN TIP OF LAKE ERIE...WITH LOW LEVEL WIND TRAJECTORY TAKING
MOST OF THE MORE GENERAL SNOW COVERAGE JUST NORTH AND EAST OF THE
FORECAST AREA. EKN HAS REPORTED -SN FOR 3 HOURS...YET VSBYS HAVE
NOT DROPPED BELOW 8SM INDICATING NOTHING MORE THAN FLURRIES
OCCURRING HERE. WV IMAGERY ALSO SHOWING WEAK UPPER TROUGH RAPIDLY
PUSHING EAST ACROSS CENTRAL OH. NOT SEEING ANY REPORTS OF -SN OUT
THAT WAY IN SFC OBS...BUT AM A BIT CONCERNED THAT THIS FEATURE
MIGHT TRIGGER A FEW FLURRIES ACROSS THE NORTHERN ZONES IN GENERAL
ON ITS WAY ACROSS. AFOREMENTIONED WIND TRAJECTORIES WILL SLOWLY
CONTINUE TO BACK SLIGHTLY AND THUS EXPECT THE SNOW TO OUR
NORTH/EAST TO CONTINUE TO SHIFT AWAY FROM THE AREA THIS MORNING.
BY 12Z THIS MORNING...TROUGH AXIS SHOULD BE EXITING THE NORTHEAST
ZONES. MIGHT CONTINUE A TOKEN FLURRY MENTION EXTREME NE MOUNTAINS
RIGHT AT THE OUTSET OF THE FORECAST PACKAGE 12Z...BUT THIS WILL
END RAPIDLY IF NOT PRIOR TO 12Z.

THE BIGGER STORY TODAY WILL OBVIOUSLY BE THE MUCH COLDER
TEMPERATURES IN THE WAKE OF THE COLD FRONT AS COLD HIGH PRESSURE
BUILDS IN TOWARDS OUR AREA. CONTINUED PREV FCST THINKING WITH TEMPS
CONTINUING TO SLOWLY DROP OR REMAIN STEADY INTO THE MID/LATE MORNING
HOURS BEFORE SOME MODEST TEMP RECOVERY TAKES PLACE DURING THE
AFTERNOON. STILL EXPECT MAX TEMPS TO TOP OUT ONLY IN THE LOW/MID 20S
FOR MOST OF THE LOWLANDS...PERHAPS SOME UPPER 20S IN THE COALFIELDS.
TEMPS ACROSS THE HIGHEST PEAKS OF THE EASTERN MOUNTAINS WILL
STRUGGLE TO GET OUT OF THE SINGLE DIGITS ONCE THE TEMPS DROP THIS
MORNING. THERE MAY BE A BIT OF A BREEZE FOR THE LOWLANDS TO CREATE A
BIT OF A WIND CHILL AS WELL...BUT THE HIGH PEAKS WILL SEE MUCH LOWER
WIND CHILL VALUES TODAY WITH NOT ONLY THE COLDER TEMPS BUT STRONGER
WINDS AS WELL AROUND 15-20MPH WITH GUSTS TO AROUND 30MPH MUCH OF THE
DAY. AS A RESULT...WIND CHILL READINGS FOR LOCATIONS SUCH AS
SNOWSHOE WILL SEE WIND CHILL READINGS AROUND MINUS 10 FOR MOST OF
THE MORNING AND INTO THE AFTERNOON HOURS. DO EXPECT CLOUDS TO BREAK
FROM WEST TO EAST AS USUAL DURING THE MORNING HOURS...WITH ALL
LOCATIONS SEEING AT LEAST PARTLY CLOUDY SKIES FOR THE AFTERNOON.

ANOTHER COLD NIGHT IS ON TAP FOR THE AREA TONIGHT WITH SFC HIGH
PRESSURE CENTERED ROUGHLY OVER THE SMOKY MOUNTAIN REGION BY 06Z-12Z
FRI MORNING. LIGHT SURFACE WINDS WILL CONTINUE...PERHAPS A BIT
STRONGER OVER THE NORTHERN ZONES WITH A TIGHTER PRESSURE GRADIENT IN
PLACE. WEAK WARM ADVECTION AT 850MB WILL BE IN PLACE WHICH MAY KEEP
SE OHIO ZONES TEMPS UP JUST A BIT. FURTHER EAST ACROSS CENTRAL WV
LOWLANDS...THESE LOCATIONS SHOULD BE ABLE TO REMAIN BELOW THE WARM
ADVECTION AND DROP DOWN TOWARDS PROGGED DEWPOINTS...SO EXPECT A
FROSTY NIGHT IN THE VALLEYS OF THE CENTRAL WV LOWLANDS.
OVERALL...VERY LITTLE CHANGE WITH PREV FCST WITH MINS DOWN INTO THE
TEENS FOR MOST LOCATIONS...PERHAPS RIGHT AROUND 20 FOR THE
COALFIELDS.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A COLD FRONT APPROACHES FROM THE NORTHWEST EARLY FRIDAY.
CONSEQUENTLY...WESTERLY FLOW WILL INCREASE BRINGING MILDER
TEMPERATURES AS NOTICED BY MODELS AT H85 TEMPERATURE INCREASE OF 5
DEGREES. CONDITIONS WILL BE DRY ON FRIDAY. THE COLD FRONT
POSITIONS WEST TO EAST ACROSS WV AND OH BY 00Z SATURDAY.
THEN...WINDS WILL INCREASE AS THEY TURN FROM THE SOUTHWEST FRIDAY
NIGHT...BRINGING A BAG OF MIXED PCPN THROUGH EARLY
SATURDAY...CHANGING TO ALL RAIN BY SATURDAY AFTERNOON AS WARM
ADVECTION CONTINUES...BRINGING THE FREEZING LEVEL AT H85 OVERHEAD.

TEMPERATURE DROPS BEHIND THE FRONT TRANSITIONING PCPN TO ALL SNOW
SATURDAY NIGHT WITH SIGNIFICANT SNOW ACCUMULATIONS ACROSS PORTIONS
OF SOUTHEAST OH AND NORTHEAST MOUNTAINS OF WV.

FORECAST SOUNDINGS AND HPC GUIDANCE SUGGEST SIGNIFICANT FREEZING
RAIN THREAT ACROSS THE EASTERN SLOPES OF THE APPALACHIANS SATURDAY
NIGHT INTO SUNDAY. KEPT MENTION IN HWO ANTICIPATING WINTER
WEATHER HAZARDS MAY BE NEEDED.

USED A BLEND OF NAM AND GFS MOS FOR TEMPERATURES THROUGH THE
PERIOD.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS SHOWING THE SYSTEM PULLING OFF TO THE EAST SATURDAY
NIGHT...WITH COLD AIR FILTERING IN BEHIND THE SYSTEM. SOME BRIEF
SNOW IS POSSIBLE AS THE SYSTEM PULLS OFF...THEN POSSIBLY LINGERING
INTO SUNDAY IN THE MOUNTAINS. SOME DEBATE ON THE MODELS AS TO HOW
COLD THE AIR WILL BE...WHICH COULD SIGNIFICANTLY INFLUENCE UPSLOPE
POTENTIAL.

MODELS THEN STRUGGLE WITH A SERIES OF NORTHERN STREAM DISTURBANCES
AND THEIR TIMING. FOR NOW...WILL RUN A BLEND OF THE ECMWF...ECMWF
ENSEMBLE MEAN AND CANADIAN ENSEMBLE MEAN. CONFIDENCE OF THESE
FEATURES FOR THE BEGINNING OF THE NEXT WORK WEEK REMAINS LOW.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
POST FRONTAL LOW STRATUS WITH AN OCCASIONAL FLURRY CURRENTLY OVER
MUCH OF THE FORECAST AREA THIS MORNING...WITH SOME CLEARING ACROSS
THE FAR NORTHWEST PORTION OF THE FORECAST AREA. CIGS APPEARING A
BIT SLOWER TO SCATTER THAN INITIALLY FORECAST AT 06Z AND AS SUCH
WILL KEEP A MVFR CIG FOR LOCATIONS EAST OF THE OHIO RIVER JUST
ANOTHER ONE TO TWO HOURS OR SO THIS MORNING. STILL...EXPECT
STRATUS TO SCATTER BY THE 14-16Z TIME FRAME FOR THE LOWLANDS AND
PERHAPS ANOTHER HOUR OR SO FOR THE EASTERN MOUNTAINS.

EXPECT VFR CONDITIONS TO PREVAIL AFTER 18Z FOR ALL LOCATIONS
THROUGH THE REMAINDER OF THE VALID PERIOD. NORTHWEST WINDS WILL
GRADUALLY SHIFT TO THE SOUTHWEST BY END OF PERIOD...AND MAY
PERHAPS BE A BIT BREEZY ACROSS THE LOWLANDS TODAY BUT STRONGER AND
GUSTIER OVER THE EASTERN MOUNTAINS.

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

FORECAST CONFIDENCE: MEDIUM THIS MORNING...HIGH AFTER 18Z.

ALTERNATE SCENARIOS: SCATTERING OF MVFR CIGS MAY VARY BY AN HOUR
OR SO THIS MORNING FROM FORECAST...PARTICULARLY OVER THE EASTERN
MOUNTAINS.

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       11   12   13   14   15   16   17   18   19   20   21   22
EST 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
CRW CONSISTENCY  H    H    M    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  L    L    L    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    M    M    H    H    H    H    H    M    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  M    M    M    H    H    H    H    H    H    H    H    H

AFTER 12Z FRIDAY...
IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY AND
POSSIBLY LINGERING IN SNOW SHOWERS SUNDAY.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...ARJ/50
NEAR TERM...50
SHORT TERM...ARJ
LONG TERM...RPY
AVIATION...50