127
FXUS61 KRLX 150950
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
550 AM EDT Wed Jul 15 2026

.WHAT HAS CHANGED...
Temperatures were lowered slightly for today, with heat indices
expected to remain below Heat Advisory level. The forecast remains
on track otherwise, with haze maintained. Chances for heavy showers
and thunderstorms have increased Friday and into the weekend, with
the highest chances now forecast for Saturday afternoon and night.

&&

.KEY MESSAGES...
1) Hazy and hot conditions are expected today and Thursday, with
areas near the Ohio River on the cusp of advisory-level heat
Thursday.

2) Scattered-to-numerous, heavy showers and thunderstorms are
forecast to arrive late Friday and last through the weekend,
bringing along a risk for localized flash flooding and strong wind
gusts.

&&

.DISCUSSION...
KEY MESSAGE 1...

In the mid/upper-levels, the center of the subtropical ridge
continues to meander over the Upper Midwest, and was objectively
analyzed at 600 dam per the 15/00Z UA charts. Modulation of the
subtropical ridge is also underway, as it is substantially more
elongated with respect to longitude compared to 24 hours via the
influence of a shortwave trough digging southeastward into eastern
Quebec. The northern-stream jetlet remain phased, with a 250 mb jet
streak analyzed at 125 kt stretching from the Canadian Prairie into
lowlands of the James Bay. As the phased, northern-stream jetlet
continues to translate east-southeastward and attain a larger
meridional component, it will continue to attenuate the amplitude of
the subtropical ridge while also causing its center to rotate over
the CWA by tonight before its eventual demise heading into Thursday
as the large-scale cyclone becomes vertically-stacked over far
northeastern Canada.

A benign surface pattern will persist across the CWA today through
Thursday afternoon, leading to stagnant air and the trapping of a
high-altitude haze layer as the center of the subtropical ridge
progresses over the region. Haze has been maintained, with slight
reductions to visibility possible this afternoon and once again
Thursday afternoon. High temperatures today were lowered a few
degrees, as the thickness of the haze should offset the full effects
of diabatic heating today. As a result, heat indices are forecast to
peak in the middle 90s across most of the lowlands, with a few
locales along and northwest of the Ohio River reaching the upper
90s. Therefore, a Heat Advisory will not be issued for today. Highs
for Thursday may need to be lowered a couple of degrees depending on
the extent of the haze layer, but high-resolution guidance, in
addition to the evolution of the synoptic-scale background, suggest
that dispersion of the haze layer may be underway Thursday. Despite
slight reductions to dewpoints in the official forecast, heat
indices may still approach the century mark for portions of the
lowlands Thursday. (Dewpoints were adjusted downward a couple of
degrees this afternoon, too.) Overnight lows will bottom out in
the lower 70s this morning and Thursday morning. Otherwise, typical
river valley fog is expected during the predawn hours today and
Thursday, with fog mixing out quickly after sunrise.

KEY MESSAGE 2...

There is an increasing potential for heavy showers and thunderstorms
starting late Friday and lasting through the weekend, with the
highest rain chances forecast Saturday. On Friday morning, the
mid/upper-levels will feature the vertically-stacked cyclone
discussed in Key Message 1 wobbling over far northeastern Canada,
with the core of the phased jet stream remaining displaced over New
England. The decayed center of the subtropical ridge will be exiting
offshore into the Atlantic Ocean while becoming absorbed into the
Bermuda High, allowing a tongue of moisture originating from Gulf
Basin to advect poleward towards the Rust Belt. This moisture axis
will then intersect a shortwave trough embedded within the broader
belt of cyclonic flow to the north of the region will be digging
southeastward towards the Rust Belt, setting the stage for showers
and storms to arrive late-day Friday. Meanwhile, the arrival of a
synoptic cold front sagging southward into the CWA will bolster the
potential training storms due to the frontal-parallel orientation of
the flow throughout the cloud-bearing layer.

The nearby 15/00Z RAOBs sampled an established EML despite the very
warm mid-levels, but with the geopotential height falls associated
with the shortwave trough ejecting over the CWA Friday evening,
MUCAPE values are forecast to increase as high as 2,500-3,000 J/kg
amidst PWAT values climbing towards the 99th percentile heading into
Saturday. The airmass will be prime for very efficient rainfall late
Friday into Saturday, with a more-intense shortwave trough forecast
to arrive over the Great Lakes region Saturday night. This would
position the CWA within the right-entrance region to the 300 mb jet
streak oriented parallel to the synoptically-driven low-level jet
trailing the preceding stalled front, which will have advanced
northeastward following warm-frontogenesis ahead of the approaching
shortwave trough. Strong theta-e advection amidst the unidirectional
flow aloft ahead of a secondary cold front approaching from the
north will facilitate the potential for numerous swaths of heavy
rainfall, especially across the mountainous terrain as the upslope
component to the flow is maximized. Training storms will exacerbate
the potential for flash flooding, with warm-cloud depths as high as
16 kft AGL yielding highly efficient rainfall processes. Strong to
even severe-caliber downbursts may accompany any organized cores
given the magnitude of hydrometeor loading within updrafts, but the
overall risk this weekend is geared towards the potential for flash
flooding. Mesoscale details will become better resolved over the
next 48 hours. Showers and storms will linger into Sunday, with
renewed rain chances continuing into next week as the cyclonic gyre
persists over east-central Canada.

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
Flight conditions will rapidly improve following the dissipation of
river valley fog after 12Z. Winds will remain calm-to-light today,
with the direction becoming west-to-west-northwest. Haze has been
maintained with this TAF cycle, although VSBYs are still forecast to
remain VFR, but could fall to 6SM at times. Valley fog will form
during the predawn hours Thursday, with conditions ranging from MVFR
to IFR at KCRW, KCKB, KEKN, KHTS, and KPKB. KBKW is forecast to
remain VFR throughout the TAF period. Check density altitude this
afternoon due to hot surface temperatures.

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

FORECAST CONFIDENCE: Medium for fog through sunrise today, but
high otherwise through this evening.

ALTERNATE SCENARIOS: Localized reductions to visibility from
haze this afternoon. Fog may vary from the forecast during the
predawn hours Thursday.

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  M    M    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    L    L    H    H    H    H    H    H    H    H
PKB CONSISTENCY  M    M    M    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  L    L    L    H    H    H    H    H    H    H    H    H

AFTER 12Z THURSDAY...
Valley fog will be possible each morning through Friday. The
potential for heavy showers and thunderstorms will arrive late
Friday, with chances for heavy showers and storms lasting through
the weekend. IFR or lower may accompany storms, with the possibility
for strong surface wind gusts. Check density altitude Thursday
afternoon due to hot surface temperatures.

&&

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

&&

$$

DISCUSSION...Sincavage
AVIATION...Sincavage