497
FXUS61 KRLX 172327
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
727 PM EDT Mon Aug 17 2026

.WHAT HAS CHANGED...
00Z Aviation Forecast Discussion update.

Aviation discussion updated at 0930Z

In coordination with the Jackson KY forecast office, the Flash
Flood Watch has been expanded to cover our remaining counties
in southern West Virginia and southwest Virginia. Convective-
allowing models show the potential for up to 2 inches of
new rainfall today in these areas, which may exceed flash flood
guidance.

&&

.KEY MESSAGES...
1.) Heavy rainfall may lead to additional flash flooding and
tree damage across the region, especially the southern
coalfields and southwest Virginia, through 2 AM Tuesday.

2.) Widespread low stratus and dense valley fog will build
overnight tonight into Tuesday morning across much of the
region, creating low visibility for the morning commute Tuesday.

3.) A temporary dry break is expected Tuesday through early
Wednesday before another cold front brings renewed shower and
thunderstorm chances with flash flood potential Wednesday night
through Thursday.

&&

.DISCUSSION...
KEY MESSAGE 1...

Destabilization is under way across the region in the wake of a
decaying morning convective complex, with the most robust
clearing located across southern areas. The strongest
convective cores will graze portions of southwest Virginia and
the southern coalfields where SPC has added a slight risk of
severe storms. Additional scattered to numerous showers and
thunderstorms are already developing along a slow-moving
surface cold front pressing southeastward across the Middle Ohio
Valley.

The thermodynamic environment remains exceptionally moist,
characterized by precipitable water values approaching 2.0
inches, which sits well above seasonal climatology. Soundings
display long, skinny instability profiles with Mixed-Layer CAPE
reaching 800 to 1200 J/kg, up to 1500 J/kg across southern
counties. These soundings feature deep warm cloud depths
exceeding 12000 feet, supporting highly efficient warm rain
production with rainfall rates of 1 to 2 inches per hour. Flow
at H700 around 30 to 35KTs out of the west will keep individual
convective cores moving at a modest pace. However, low-level
convergence along the cold front as it sinks slowly to the
southeast runs nearly parallel to the mid-level flow, which may
promote cell training over the same drainages.

Deep-layer bulk shear of 25 to 30KT will favor a predominantly
multicellular storm mode. Low-level hodographs show modest
curvature, yielding effective storm-relative helicity of 70 to
100 m2/s2. This shear profile could foster brief updraft
rotation in any semi-discrete cells, maintaining a low, though
non-zero, threat for a brief tornado. While the primary severe
wind potential remains concentrated along our southern border
where instability is maximized, antecedent saturated ground
conditions mean that even sub-severe wind gusts of 35 to 45 mph
can uproot exposed trees.

Given severely compromised soils from repeated heavy rainfall
over the preceding days, 3 hour flash flood guidance is
generally between 1.0 and 1.5 inches across much of the forecast
area. High precipitation rates will result in rapid runoff into
small streams. A Flash Flood Watch remains active through 2 AM
EDT Tuesday.

KEY MESSAGE 2...

In the wake of the cold frontal passage late tonight, surface
winds will diminish to 5 mph or less under weak northwesterly
flow. While we should maintain at least some mid-level cloud
cover, will likely see surface temperatures falling to
saturation by early Tuesday morning. Widespread low stratus and
fog is expected expected to form over much of the area heading
into Tuesday morning which could impact the morning commute.

KEY MESSAGE 3...

A brief period of dry weather will take hold Tuesday afternoon
through most of Wednesday as high pressure builds across the
Central Appalachians and column moisture decreases behind the
cold front. Precipitable water values drop to around 1.0 to 1.2
inches on Tuesday, allowing small streams and creeks an
opportunity to recede. However, subsurface soil moisture will
remain nearly saturated, leaving infiltration capacity severely
degraded.

Atmospheric moisture will pool northward again late Wednesday
into Wednesday night ahead of the next upper-level shortwave
trough and cold front. Precipitable water values rise back
toward 1.8 inches by Thursday morning. Upper-level dynamics will
strengthen as the right rear quadrant of an H200 jet streak
positions over the Middle Ohio Valley, providing broad synoptic
scale ascent. With modest diurnal destabilization expected
Thursday afternoon, scattered to numerous showers and
thunderstorms will redevelop along the boundary. High
instantaneous rainfall rates falling on saturated soils will
present a renewed flash flood risk, supporting the Weather
Prediction Center Marginal Risk of Excessive Rainfall for
Thursday.

The broad synoptic pattern through the late week and upcoming
weekend will be dominated by strong mid-level ridging over the
western United States and longwave troughing centered over the
eastern tier. This configuration will keep the Central
Appalachians in northwest flow aloft, directing periodic
shortwaves and secondary cold fronts through the region every
couple of days.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As the rain showers settle down low clouds should clear out and
dense fog becomes the main theme going into the overnight
hours. Cold frontal passage takes place and should clear out
clouds enough to help with fog formation. Low stratus should
evolve along with the restrictions to VIS unless a site does not
decouple, then just low stratus will dominate. Expect LIFR or
worse conditions until 13Z then the stratus should scatter out
shortly thereafter. VFR will become dominate by then and last
through the afternoon.

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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: The timing and spatial extent of fog
overnight may vary depending on extent of partial clearing
behind the cold 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                                                            TUE 08/18/26
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  M    M    M    M    H    M    H    H    H    H    H    H
HTS CONSISTENCY  M    M    M    M    M    H    L    L    M    L    H    H
BKW CONSISTENCY  H    H    M    H    H    H    L    L    L    L    L    L
EKN CONSISTENCY  M    H    H    H    H    L    M    M    H    H    H    H
PKB CONSISTENCY  M    M    M    H    H    M    L    M    M    M    M    M
CKB CONSISTENCY  M    M    M    L    H    L    M    H    H    H    H    H

AFTER 00Z WEDNESDAY...
IFR valley fog possible Wednesday morning.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flood Watch until 2 AM EDT Tuesday for WVZ005>011-013>020-
     024>034-039-040-515>526.
OH...Flood Watch until 2 AM EDT Tuesday for OHZ066-067-075-076-
     083>087.
KY...Flood Watch until 2 AM EDT Tuesday for KYZ101>103-105.
VA...Flood Watch until 2 AM EDT Tuesday for VAZ003-004.

&&

$$

DISCUSSION...JP
AVIATION...JZ