266
FXUS63 KJKL 121852
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
252 PM EDT Tue Aug 12 2025

.KEY MESSAGES...

- Scattered showers and thunderstorms will develop this afternoon
  into the evening, bringing the potential for brief, heavy
  downpours

- Storms on Wednesday will be capable of producing torrential
  rainfall, creating a risk for localized flooding or flash
  flooding, especially where storms move over the same areas
  repeatedly.

- Above average temperatures in the upper 80s and lower 90s will
  return for the weekend.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 252 PM EDT TUE AUG 12 2025

The overall synoptic pattern has shifted since yesterday. While a
high-pressure system is still largely dominant, a few disturbances
are introducing increasing cloud cover and precipitation. The first
of these is a surface trough located across much of the Southeast.
To the northwest, a slow-moving cold front extends southwestward
from a closed low situated just south of the Hudson Bay region.
Locally, showers and isolated thunderstorms are beginning to develop
across much of the CWA and are expected to persist through the
afternoon and evening.

Showers and thunderstorms will continue to develop and become more
widespread this afternoon. Forecast soundings and SPC mesoanalysis
indicate that SBCAPE values in the area could reach 2,000 to 3,000
J/kg. Wind shear is expected to be weak, which will largely minimize
the threat for severe storms, but a feisty storm or two cannot be
entirely ruled out. The soundings also suggest a high potential for
heavy rainfall, with PW values exceeding 2.00 inches, which is in
the 90th percentile for this time of year. Combined with a tall and
skinny CAPE profile, this indicates that the showers and storms
could be very efficient, with most of the available moisture being
realized as rainfall. In short, these storms could produce a
significant amount of rain in a short period. Areas that experience
repeated rounds of these showers could be susceptible to hydro
issues. While this is occurring locally, the upper-level trough
responsible for the Hudson Bay low will pivot to the northeast,
allowing the cold front to continue its approach toward the
Commonwealth. Temperatures will climb into the upper 80s this
afternoon. Showers and storms will dissipate overnight, but guidance
suggests that complete clearing may not be achieved, so fog is not
expected in the valleys. Overnight temperatures will fall into the
mid to upper 60s.

As the front dives southeastward toward the Commonwealth, a higher
coverage of showers and storms is expected on Wednesday compared to
today. Similar conditions are forecast, but increased moisture and
stronger lift will support widespread thunderstorms in an
environment favorable for heavy rainfall. As with Tuesday, the
threat for severe weather is minimal but not zero, while the threat
for heavy rainfall and potential flash flooding is considerably
higher. Forecast soundings for Wednesday again show PW values over
2.00 inches and tall and skinny CAPE profiles. Therefore, the
potential for heavy rain and flash flooding from repeated rounds of
storms exists. This threat is also highlighted by the WPCs upgrade
of the Excessive Rainfall Outlook from a Marginal to a Slight Risk.

The period will be dominated by several rounds of showers and storms
that could produce heavy rain and potentially lead to flash
flooding. Temperatures today will reach the upper 80s, but the
frontal approach on Wednesday will bring highs down into the lower
80s. Overnight temperatures will still range from the mid to upper
60s, and possibly into the low 70s.

.LONG TERM...(Thursday through Tuesday)
Issued at 252 PM EDT TUE AUG 12 2025

The long-term period begins with an approaching cold front from the
northwest stalling, becoming stationary, and orienting east-west
along the KY-OH border. This is due to the associated 500-mb trough
continuing to lift northeastward over the eastern Canadian
provinces, thus replacing northwesterly winds with quasi-zonal flow.
This flow pattern will remain through Friday morning, bringing with
it weak steering flow. Along with above-average moisture and a
stationary boundary that will serve as a forcing mechanism, the set-
up is primed for heavy rain concerns. However, compared to
Wednesday, the ingredients aren`t as favorable. By Friday midday, a
weak ridge approaches the area, bringing north-northwesterly flow
that cuts off the moisture source present on the prior days. Warmer,
drier conditions will prevail through the remainder of the period,
with only diurnally-driven popup convection expected.

The main concerns are through Thursday night with forcing associated
with the east-west oriented stationary front, near unidirectional
flow, and above-average moisture profiles. The threat will be higher
in our southeastern counties, where PWs are forecasted to be higher
(1.6-1.9 inches). With these factors in place, WPC maintains a
Marginal (level 1/4) risk for flash flooding Thursday through Friday
morning for our entire forecast area, and through Friday night for
our far eastern counties. Dry ground conditions will keep higher-
impact flooding concerns at a minimum, but multiple rounds of heavy
rain (or simply slow-moving, high-efficiency storms) could lead to
localized hydrologic concerns. Due to the broader precip potential
and cloud cover, high temperatures should also be lower (mid to
upper 80s) on Thursday and Friday.

By Friday midday, a weak ridge approaches from the west, leading to
mid-level northwesterly flow that cuts off the main moisture driving
the prior flooding concern. Weak perturbations could pass around the
ridge, thereby allowing for popup convection to initiate, but more
isolated and diurnal in nature. The associated 500-mb high will stay
to our west through the period, so expect this setup to prevail the
remainder of the period. Generally sunny days will lead to highs of
90-95F. Clear conditions will also lead to the potential for
nighttime fog in the river valleys, especially with increased ground
moisture after the Wed/Thurs event.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 142 PM EDT TUE AUG 12 2025

TAFs are as combination of MVFR and VFR with this issuance. KSME
and KLOZ are currently MVFR as showers and isolated storms are
moving north from Tennessee. The remaining sites are VFR but as
precipitation continues to move north and increases in coverage;
terminals could see a reduction to MVFR. A brief lull in activity
is expected during the early overnight but after 06Z; activity
develops and continues through the remainder of the TAF period.
Winds are forecast to be mostly light and variable outside of
ongoing convection.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...VORST
LONG TERM...HARDY
AVIATION...VORST