Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 230216
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
1016 PM EDT Tue Aug 22 2017

.SYNOPSIS...
Cold front crosses tonight. Cooler and drier high pressure into
the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 1015 PM Tuesday...

The cold front continues to slowly move our way. As of 02Z the
front was approaching a line from SDF-CMH-CLE. The line of
thunderstorms has really weakened, with mainly scattered
showers along and south/east of the Ohio River now. Did not make
any huge changes to POPs as many are still getting in on one of
these showers -- thus likely POPs still warrantied across
WV...and eventually into SWVA.

As of 3 PM Tuesday...

A rather classic set up for severe weather presents itself this
afternoon and evening. A strong cold front extended from
southeast MI to southern IL early this afternoon. In an axis
ahead of it, surface dew points into the lower 70s, CAPE of 1500
to 2000 J/kg and 45 to 50 kts of deep layer bulk shear provide
ample potential for severe weather for late August, especially
given prime heating time.

Already approaching the Ohio River as of early afternoon, the
severe threat continues through the evening hours, well out
ahead of the advancing cold front. The severe threat will end
prior to the frontal passage on loss of heating and of some
dynamics. The front itself reaches the Ohio River around
midnight, and then crosses the remainder of the forecast area by
dawn Wednesday. After low clouds and some fog to start, drier
northwest flow will bring cooler and less humid weather
Wednesday.

Temperatures looked to be on track given the latest guidance
and weather pattern, notwithstanding wet bulb cooling, which led
to a somewhat lower than guidance forecast for early tonight.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 230 PM Tuesday...

High pressure builds into the region Wednesday night for drier
weather. Looking to overall be a dry period, with warm sunny
days, and foggy mornings under high pressure. A shortwave trough
will affect the area on Thursday, which could create a few light
showers or sprinkles, but overall, main threat for this appears
to be low, and to our north. It will however, bring in an
additional shot of cooler air.

Overall, will be nice weather, with the much cooler and less
humid conditions, and sunny weather.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 230 PM Tuesday...

Most of the extended period will remain dry, although there will
be a slight chance to chance for showers and thunderstorms,
mainly across the higher terrain, possibly drifting westward
into the lowlands. Expecting a slight increase in temperatures
from the short term.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
As of 800 PM Tuesday...

Showers and thunderstorms ahead of a cold front moving through
late this evening, with IFR possible in the stronger storms.
Tried to time the IFR into CKB, HTS and CRW. Will likely need to
amend at EKN and BKW as timing becomes more certain.

As a cold front moves through, expected ceilings to drop into
MVFR to IFR. Models indicating potential for dense fog, but
think with overcast skies and some flow that dense fog is not
likely.

Ceilings will gradually scatter out and lift to VFR through the
morning on Wednesday.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Timing of storms and IFR may vary. Low
chance that some dense fog could develop with very humid low
levels ahead of the front.

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                                                            WED 08/23/17
UTC 1HRLY       00   01   02   03   04   05   06   07   08   09   10   11
EDT 1HRLY       20   21   22   23   00   01   02   03   04   05   06   07
CRW CONSISTENCY  H    M    M    H    M    H    H    M    M    M    M    L
HTS CONSISTENCY  M    M    L    H    H    M    M    M    M    M    M    L
BKW CONSISTENCY  M    M    M    M    M    M    M    M    L    H    M    L
EKN CONSISTENCY  M    M    H    H    H    H    M    L    L    L    M    L
PKB CONSISTENCY  M    H    H    H    H    H    M    M    M    M    M    L
CKB CONSISTENCY  H    M    H    H    H    H    H    H    H    M    M    L

AFTER 00Z THURSDAY...
River valley fog possible each morning through the weekend.

&&

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

&&

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



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