Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 230826
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
326 AM EST Tue Jan 23 2018

.SYNOPSIS...
Low pressure system exits northeast, but remains unsettled
through Wednesday. Warmer to end the week. Cold front next
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 250 AM Tuesday...

Line of showers weakening as it passes the I79 corridor this
morning. Still have lingering showers behind this line, and the
low level cold air advection lagging behind the cold front a
bit, but will see slowly falling temperatures through the day.
The broad upper level cyclone has pulled in dry air that will
provide breaks in the clouds for the first part of the day, but
the low level moisture returns and timed this with the higher RH
values in the 925mb layer and the continuing cold air advection.
This will last through tonight, and ramp the sky cover grids to
overcast after 00Z Wednesday.

That low level moisture should end up deep enough to warrant
light isolated to scattered snow showers, most persistent in the
mountains. Amounts in the near term will be light, with the only
amounts over an inch in the highest ridges.

Winds will be on the increase over the next several hours in
descending air in the cold advection process. Will be
transferring momentum down to the surface from around 800mb, but
should stay well below advisory criteria. Highest elevations
will receive the highest gusts.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
As of 325 AM Tuesday...

A 500mb shortwave trough will swing through on Wednesday.
Moisture is fairly limited, but with 850mb temps in the -10C
range, should still be able to get some light snow
showers...especially across the northern mountainous counties.
The snow showers should taper off from west to east overnight.
Still have some cold air advection lingering Thursday morning,
so cannot rule out some lingering flurries, but opted to not
include them at this point since moisture will be limited and
the air is not super cold.

Surface flow turns SW Thursday into Friday with a surface high
drifting toward the NC/VA coast. This will bring a warming trend
to end the work week.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
As of 320 AM Tuesday...

Models remain fairly unhelpful for weekend system. The GFS is
much faster with the system, bringing a cold front through late
Saturday and Saturday night. The GFS is fairly progressive and
is dry by midday Sunday. The ECMWF is much slower with this
system, as it tries to cutoff the 500mb flow and pulls a
southern stream surface low up the Appalachian spine Sunday into
Monday. With the stronger system on the ECMWF -- enough cold
air would arrive for a changeover to snow Sunday night into
Monday. The GFS is much warmer... and mainly dry at this time.
For now did not stray far from a consensus blend, having high
chance POPs Saturday night into Sunday.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
As of 1245 AM Tuesday...

Line of showers with isolated embedded thunder now crossing the
Ohio River and pushing slowly to the east, while individual
cells are moving more rapidly to the north northeast. The
history of this line and the cells within it are very brief IFR
visibilities in rain and winds generally to 35kts in gusts. The
timing of these and their arrival are still challenging, even
in the very near term of the aviation forecast, so some
amendments may be necessary.

Behind the line and cold frontal passage, winds veer to the
west southwest with gusts in the 25-35kt range. Ceilings will
come down into prevailing MVFR between 1500-2700ft.

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


FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Frontal timing and restrictions could 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 01/23/18
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  H    H    H    H    H    H    H    H    M    L    L    L
HTS CONSISTENCY  H    H    H    H    H    H    H    M    H    L    M    L
BKW CONSISTENCY  H    H    H    M    H    H    H    H    H    M    M    M
EKN CONSISTENCY  H    H    L    M    H    H    H    H    H    M    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    M    L    L    L
CKB CONSISTENCY  H    H    M    H    H    H    H    H    H    M    M    M

AFTER 06Z WEDNESDAY...
No widespread IFR expected.

&&

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

&&

$$
SYNOPSIS...MZ/26
NEAR TERM...26
SHORT TERM...MZ
LONG TERM...MZ
AVIATION...26


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