972
FXUS61 KRLX 130928
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
528 AM EDT Thu Aug 13 2026

.WHAT HAS CHANGED...
Updated 12Z aviation discussion. Clearing skies have allowed
fog to develop over portions of SE OH and N WV this morning.

As of 327 AM Thursday...

Although forecast thinking largely remains similar in synoptic
features, considerable uncertainty remains in evolution of
mesoscale features around the periphery of heat and humidity
across the Central/Southern Plains into the Deep South. A flash
flood watch remains in effect through Friday morning.

&&

.KEY MESSAGES...
1.) Very high forecast certainty remains regarding evolution of
mesoscale features through this weekend. The environment will
support heavy to very heavy rainfall at times as convective
complexes develop around the periphery of a very hot and humid
airmass across the Southern Plains/Deep South and track
southeast under the ridge.

2.) The Flash Flood Watch remains in effect through Friday
morning for much of the area.

&&

.DISCUSSION...
KEY MESSAGE 1...

Despite reasonable model consistency regarding synoptic
features, considerable forecast uncertainty remains in the
mesoscale regarding convective evolution. The polar jet remains
largely north of the region through the period, with an
expansive upper ridge centered over the southern United States.
Weak mid-level disturbances rotating around the southern periphery
of this ridge will provide sufficient forcing for ascent to
initiate convection, which may subsequently grow upscale into
thunderstorm complexes. These complexes will propagate
southeastward down the instability gradient driven by persistent
heat and humidity from the plains. Overall confidence in the
track and timing of any of these features is low.

The thermodynamic environment is characterized by precipitable
water values near the top of climatological distribution for
mid-August, ranging from 2.0 to approaching 2.5 inches with deep
warm cloud depths supporting highly efficient rainfall
production. In the absence of being overturned upstream, MUCAPE
values will range from 2000-4000J/kg at times with persistent
regeneration of decent mid-level lapse rates owing to the
aforementioned heat extending back into the High Plains.

Overall, stronger deep layer shear associated with the belt of
stronger flow over the ridge will remain separated from the
stronger corridor of instability south of the ridge with
concerns for severe thunderstorms largely limited to upscale
growth or isolated wind damage associated with microbursts.

There is at least some potential advertised by some WRF core
members in a nose of a stronger H850 low-level jet near 30 to
35KT crossing the Middle Ohio Valley in association with an
MCV Friday morning into Friday afternoon. This would yield at
least a localized higher potential for severe storms however,
this feature remains an outlier among the guidance suite,
highlighting the overall low confidence levels.

Despite some amplification of the ridge displacing stronger
flow even farther north toward the latter half of the weekend
which would typically shelter us from summer time ridge riders
so still see some potential for a continuation of this pattern
given the expected strong instability gradient under the ridge.

In 25 years in the weather business the preceding and forecast
activity associated with this pattern represents some of the
lowest forecast confidence levels in the details (despite fair
agreement in synoptic features) I have ever experienced.

KEY MESSAGE 2...

The decision regarding the ongoing Flash Flood Watch remains
challenging from a messaging perspective. Showers and isolated
storms may impact western counties and the Metro Valley this
morning, but additional organized heavy rainfall is expected to
hold off until this evening into Friday morning. Additional
heavy rain remains possible through Friday, potentially
extending through the weekend, but forecast confidence is very
poor due to model struggles with convective advection along the
ring of fire in weaker steering flow south of the ridge crest.

Lush summer vegetation has assisted in soil recovery following
earlier rainfall this week, allowing many basins to recover
somewhat, now able to handle 1 to 1.5 inches of rain in a short
duration. In a higher confidence scenario, canceling the
current watch (likely concurrent with several neighboring
offices planning to expire their watches on time this morning)
and reissuing later with a deferred start time would be
preferred for messaging purposes. However, given substantial
uncertainty over even the next 24 hours, confidence is
insufficient to alter the existing watch at this time. As a
result, the watch continues as issued for now through Friday
morning for potential localized high water issues, with an
eventual extension possible if confidence increases in the
aforementioned potential scenarios.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
Fog has developed across the northern terminals where skies have
cleared. Should see conditions improve by 13Z. Otherwise, mainly
VFR conditions expected through the day outside of restrictions
in convection.

Isolated diurnal thunderstorms are possible this afternoon as
surface heating destabilizes the boundary layer. A somewhat
better chance for organized thunderstorm clusters arrives
overnight tonight as convective activity develops along an
instability gradient in the lower Ohio Valley and tracks east-
southeastward. However, confidence in direct impacts at any
specific terminal remains low, so have only coded VCTS for now.

Surface winds will remain light and variable overnight, turning
westerly to southwesterly at 5 to 10KTs during the day.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...

FORECAST CONFIDENCE: High, except very low for convective
coverage.

ALTERNATE SCENARIOS: Thunderstorm coverage and timing could
vary significantly based on upstream convective evolution.

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       10   11   12   13   14   15   16   17   18   19   20   21
EDT 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
CRW CONSISTENCY  L    L    L    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    M    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  L    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    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    M    H    H    H    H    H    H    H    H    H    H

AFTER 12Z FRIDAY...
Periodic chances for showers and thunderstorms continue through
early next week. Brief IFR or lower conditions will be possible
in direct thunderstorm hits or heavy downpours. Where overnight
clearing occurs over wet ground, patchy valley fog and stratus
may bring early morning MVFR or IFR restrictions.

&&

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

&&

$$

DISCUSSION...JP
AVIATION...JP