920
FXUS61 KRLX 171835
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
235 PM EDT Sun Aug 17 2025

.SYNOPSIS...
A cold front moves through tonight into Monday, then another
arrives midweek and stalls, giving rise to mainly, but not
exclusively, diurnal showers and thunderstorms most days.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 235 PM Sunday...

A cold front was sagging south of the Great Lakes early this
afternoon. Showers and thunderstorms firing up ahead of it over
southwestern Pennsylvania are likely to expand southwestward
into the middle Ohio Valley this afternoon. A somewhat separate
zone of scattered showers and thunderstorms were firing up in a
zone from northeastern WV southwestward through southeastern
Kentucky, ahead of a prefrontal trough.

All of this activity was forming amid an modestly unstable
environment and diffluent albeit light mid/upper-level flow,
and will continue to drift southeastward through much of the
area into this evening.

Instability actually diminishes mid to late this afternoon due to
mid level moistening, to the point where PW values climb
despite low level moisture decreasing. CAPE falls from 3-4 KJ/kg
to 1-2 KJ/kg as PW values rise from about 1.6 to 1.9 inches.
This will support locally heavy downpours and high rainfall
amounts given somewhat slow storm movement, but weak shear to go
along with relatively weak mid-level lapse rates will keep
storms from becoming especially strong.

The showers and thunderstorms will move southeast of the area
and/or dissipate after sunset. After that, tonight presents a
battle between fog, especially where it rains this afternoon
into this evening, and stratocumulus ahead of and along a cold
front pushing southward into the area. Convergence along the
front will be limited due to the low level flow already being
northwest ahead of it behind the prefrontal trough, so
precipitation is not anticipated as the front crosses overnight
and Monday morning.

This spells a mainly dry day Monday, as mid/upper-level ridging
builds into the area from the west. A shower could still pop in
the mountains on the elevated heat source effect, and weak
upslope on diurnal anabatic flow enhanced by an inverted low
level trough.

The showers and thunderstorms were breaking the heat across
portions of the Heat Advisory area early this afternoon. After
a warm and somewhat muggy night tonight, central guidance
reflects a slightly cooler day in the wake of the cold front on
Monday, with high temperatures only a little above normal, in
the 80s across all but the higher terrain.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 235 PM Sunday...

Low-level ridging down the east side of the Appalachians banks
moisture and clouds along the east-southeast facing slopes Monday
night into Tuesday morning. farther west, the front either buckles
back northward or washes out on Tuesday.

This will make for mainly dry weather Tuesday, although mid/upper
level ridging begins to break down, as the next southern stream
short wave trough approaches from the west. An afternoon shower,
perhaps a thundershower south, could still pop in the mountains on
the elevated heat source effect, and weak convergence from upslope
low level flow from the east-southeast and diurnal anabatic flow.

The short wave drives a cold front toward the area overnight Tuesday
night into Wednesday, and then into the area late Wednesday into
Wednesday night, before stalling/buckling over the area as an
inverted lee trough/lee low forms over the WV lowlands. This brings
the chance for showers and thunderstorms southeastward into the area
Tuesday night into Wednesday, and throughout the area Wednesday
afternoon, enhanced by daytime heating.

Thunderstorms will not become especially strong on account of
weak shear and modest instability, the latter of which is
forecast to climb to a range from just a KJ/kg across much of
the area to 1.5 KJ/kg in far western portions of the area
Wednesday afternoon. PW values forecast to range from 1.5 to
1.8 inches presents a modest heavy rainfall threat from somewhat
slow moving storms Wednesday afternoon.

The chance for showers and thunderstorms diminishes northwest to
southeast Wednesday night, even as the front gets hung up over the
area. The loss of heating and the passage of the mid/upper-level
short wave trough should conspire to bring about the demise of the
precipitation.

Central guidance reflects a slightly cooler and less muggy night
Monday night, and then a return to modestly hot afternoons and
muggy nights, although peak afternoon heat indices remain below
the Heat Advisory criteria of 100 F for the most part.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 235 PM Sunday...

The front that settles into the area as a lee trough/low midweek
hangs around through the balance of the week, with the chance for
mainly diurnal showers and thunderstorm, mainly along and
east/southeast of the feature. The main impacts from the
thunderstorms will continue to be mainly locally heavy downpours.

A long wave trough amplifies over the east next weekend, pushing a
surface fold front through the area. This would ramp up the chance
for and intensity of showers and thunderstorms on Saturday, and
then flush everything out for Sunday given the GFS solution.
The European model is slower and less amplified with this
feature, with the cold front not crossing until the early
portion of the following work week. The Canadian, in the faster
camp earlier, is now somewhere in between, and central guidance
reflects a slower solution through next weekend.

Central guidance also reflects a slight cool down on account of the
front, with temperatures holding just a little above normal this
period.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
As of 235 PM Sunday...

Showers and thunderstorms firing up across southeastern portions
of the area early this afternoon will be out of CRW 19Z and
impact BKW and possibly EKN 19-21Z. Thunderstorms may still fire
up farther north this afternoon, close to a cold front sagging
south of the Great Lakes. These storms may impact PKB and CKB
20-24Z and perhaps EKN again 21-01Z and even CRW, HTS and BKW
22-01Z.

The thunderstorms could produce MVFR to IFR conditions along
with erratic, gusty winds. Expect VFR conditions outside of the
precipitation this afternoon and evening.

Tonight presents a battle between fog, especially where it
rains this afternoon into this evening, and MVFR stratocumulus
ahead of and along a cold front pushing southward into the area.
IFR stratus is also possible in the mountains overnight into
Monday morning.

The fog and especially the low clouds may take a while to burn
off Monday morning, the fog by 14Z and the clouds lifting into
a VFR afternoon cumulus field.

A prefrontal surface trough has already turned the flow surface
and aloft to light northwest, and it will go light north to
northeast behind the cold front overnight tonight into Monday.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: Medium with fog. Low to medium with timing
of showers and thunderstorms.

ALTERNATE SCENARIOS: Timing and intensity of showers and
thunderstorms could vary. Timing and placement of fog and low
clouds forming overnight could vary, as can timing of
improvement Monday morning.

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       15   16   17   18   19   20   21   22   23   00   01   02
EDT 1HRLY       11   12   13   14   15   16   17   18   19   20   21   22
CRW CONSISTENCY  H    H    H    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  M    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    M    M    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z MONDAY...
Brief IFR conditions possible in showers and thunderstorms
Wednesday afternoon and evening.

IFR possible in river valley fog most mornings the rest of the
work week, perhaps along with stratus Thursday morning.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Heat Advisory until 7 PM EDT this evening for WVZ005>008-
     013>015.
OH...Heat Advisory until 7 PM EDT this evening for OHZ083-085>087.
KY...Heat Advisory until 7 PM EDT this evening for KYZ101>103-105.
VA...None.

&&

$$

SYNOPSIS...TRM
NEAR TERM...TRM
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...TRM