Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 140828
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
328 AM EST Tue Nov 14 2017

.SYNOPSIS...
High pressure builds on Tuesday. Cold front crosses late
Wednesday. High pressure crosses Thursday night. Strong cold
front for Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 200 AM Tuesday...

Abundant low level moisture and dry air aloft will continue to
produce drizzle and low clouds across most parts of the CWA this
morning. Then, some clearing will be possible especially across
the lowlands. With low level moisture, expect diurnal cu
development during the afternoon hours.

Models show H850 temperatures from minus 4 to minus 1 today
keeping the sfc temperatures few degrees below normal.
Widespread freezing conditions expected tonight as sfc
temperatures drops into the lower 30s.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 300 AM Tuesday...

Weak return flow out ahead of an approaching cold front will
send temperatures back into the upper 50s for a large portion of
the area on Wednesday. Models continue to be in fairly good
agreement with the arrival of the front Wednesday evening into
the Ohio Valley. Still lacking any significant moisture and with
weak forcing in zonal flow aloft, this front will push through
the area fairly quickly with just a light rainfall. By Thursday
morning we may see a brief transition to a few snow showers in
the mountains as some colder air briefly pushes in, but do not
think we will see much in the way of accumulation before the
upper trough pulls out by early Thursday afternoon. Brief
surface high and upper ridge moves in behind the front and this
should make for a good radiational cooling night, with lows
likely dipping below freezing by early Friday morning.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 325 AM Tuesday...

As we head into the weekend, model solutions diverge with the
timing of a potent short wave and associated surface cold front.

GFS strengthens the low tracking out of the Rockies and NE over
the Great Lakes much deeper than the Euro. The overall pattern
is much more amplified as well with the GFS indicating closed
low and deep trough across the Eastern Conus that pushes in much
colder air behind the front, while the Euro brings in high
pressure and WAA returning by Monday. GEFS spaghetti plots
indicate there is still a ton of uncertainty in how the pattern
will materialize this weekend as well.

The operational solutions both at least have the potent cold
front that could bring a quick dumping of heavy rain and some
gusty winds, but timing is off and what happens after that
front goes through is anyones guess at this time. Hopefully the
models will sort this out better over the next few runs when
soundings can better sample the associated short wave when it
enters the West Coast on Thursday.

For now, overall forecast for this weekend is a blend of
ensemble and operational guidance. I did add a bit higher PoPs
in the favorable upslope areas in NW flow for Sunday. Even
though the Euro is not nearly as robust with the CAA behind the
front, it does indicate a 12 hour period on Sunday where some
upslope snow will be possible, and the GFS of course indicating
a higher impact upslope snow event.



&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
As of 700 AM Tuesday...

Models and sfc obs continue to show abundant low level moisture
in the wake of a low pressure system lingering through the
overnight, and into the day Tuesday, bringing low MVFR to IFR
conditions, mainly on ceilings. Expect drizzle and low ceilings
at most sites except PKB.

Ceilings will improve to MVFR/VFR by mid morning Tuesday. As the
lower atmosphere gradually mix, ceilings will lift higher
through the early afternoon hours. Mostly clear skies will
prevail later Tuesday with diurnal cu developing in the
afternoon.

Light northerly surface flow overnight will veer to
light northeast Tuesday morning, and then light east by Tuesday
afternoon.

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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Timing and extent of MVFR to LIFR
conditions may vary overnight, and timing of improvement on
Tuesday may 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                         TUE 11/14/17
UTC 1HRLY       08   09   10   11   12   13   14   15   16   17   18   19
EST 1HRLY       03   04   05   06   07   08   09   10   11   12   13   14
CRW CONSISTENCY  M    M    M    H    H    H    H    H    H    M    M    L
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    L
BKW CONSISTENCY  L    L    L    L    L    M    L    M    H    L    L    L
EKN CONSISTENCY  H    H    H    H    H    H    M    M    M    L    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    L
CKB CONSISTENCY  H    H    H    H    H    L    H    H    M    L    L    L

AFTER 06Z WEDNESDAY...
IFR possible behind a cold front overnight Wednesday night into
Thursday morning, mainly in stratus.

&&

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

&&

$$
SYNOPSIS...ARJ/MPK
NEAR TERM...ARJ
SHORT TERM...MPK
LONG TERM...MPK
AVIATION...ARJ



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