132
FXUS63 KJKL 211210
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
810 AM EDT Mon Sep 21 2026

.KEY MESSAGES...

- Unseasonably hot and muggy weather continues through today, with
  high temperatures in the mid 80s to low 90s.

- Strong to severe thunderstorms with damaging wind gusts are
  possible this afternoon and evening, primarily south of the
  Mountain Parkway.

- A stalled front brings rounds of showers and possible storms
  tonight through Wednesday, with isolated flash flooding
  possible, primarily closer to the VA-KY border.

- Cooler, drier air arrives Thursday through the weekend,
  bringing daytime highs in the 70s and nighttime lows in the 40s
  and 50s.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 454 AM EDT MON SEP 21 2026

Even though the calendar now says late September, thermometers
around eastern Kentucky still say mid-summer this morning, with
temperatures ranging from the upper 60s to mid 70s alongside
similar dew points. Observations show that some fog has formed in
sheltered valley spots under patchy cloud cover. Shower and
thunderstorm activity is noted on radar imagery from portions of
Illinois to West Virginia, mainly north of the I-64 corridor and
also north of a stalled boundary that extends from Virginia
through West Virginia, westward along and just south of the I-64
corridor to near the Jackson Purchase/Missouri Bootheel, and then
southwestward into Texas. Looking aloft, the boundary exists
under quasi-zonal flow over our region ahead of a shallow trough
over the central Plains and a weak, closed 576 dam low along the
South Dakota and Nebraska border. A shortwave trough and attending
vort lobe are found ahead of this trough, extending from southern
Illinois into east Texas.

That leading shortwave will eject eastward today, bringing
positive differential vorticity advection across eastern Kentucky
this afternoon and evening while the aforementioned frontal
boundary slowly sags south as a cold front. There will be a 30 to
50 knot jet streak at 500 hPa attending that shortwave near the
Ohio River, but the best shear appears to be north of the frontal
boundary--leaving generally around 20 to 25 kts of EBWD south of
the boundary in tandem with 1500 to 3000 J/kg of MLCAPE per RAP13
guidance. This would be sufficient for a messy mixture of pulse
and multicell convection. Additionally, steep low-level lapse
rates and PWATs well over 1.5 inches will support the potential
for water-loaded updrafts, which could collapse and lead to
downburst winds. Microburst Composite values of 3 to 6 suggest a
slight chance to chance of a downburst given a healthy storm.
Additionally, storms that do develop closer to the front could
experience closer to 30 kts of EBWD and take on weak supercellular
characteristics in spite of thinner instability-- perhaps
producing some small hail too. SPC has maintained a Marginal Risk
(1/5) for Day 1 across the area today, focusing on damaging wind
gusts as the primary hazard. Convection will likely continue
through the evening before weakening overnight as the shortwave
trough passes overhead and dampens.

The cold front stalls out along the KY/VA border by daybreak
Tuesday with the loss of upper-level support. Attention then
turns to the parent 500 hPa trough that will drift from the
Mississippi Valley eastward into the lower Ohio Valley on Tuesday,
while the embedded upper low passes from Davenport, IA to near
Chicago, IL. The front along the KY/VA border will be replaced by
a lingering surface trough during the day on Tuesday, remaining
the focus for renewed convection amidst mid-upper level
southwesterly flow ahead of the trough, which will keep 1.5+ inch
PWATs in place over southeastern Kentucky. The most numerous
convection should be close to Virginia (60+ percent PoP), while
chances taper to just a low chance (20 percent PoP) north of I-64.

In sensible weather terms, look for partly to mostly sunny skies
this morning giving way to a rising chance of showers and
thunderstorms, a few of which could be severe with damaging winds
and heavy rainfall during the afternoon and evening. It will be
hot and humid once more, with highs ranging from the mid 80s in
the northern hills to the lower 90s over the Cumberland River
Basin. Shower and thunderstorm activity diminishes this evening,
leaving behind extensive low clouds and fog. It will be a little
cooler than prior nights, with lows ranging through the 60s. For
Tuesday, clouds will be prevalent and it will be noticeably
cooler, with highs ranging from the mid 70s north to lower 80s
south. Showers and thunderstorms, mainly in the afternoon, will be
more confined to southeastern Kentucky.

.LONG TERM...(Tuesday night through Sunday)
Issued at 310 AM EDT MON SEP 21 2026

The extended period begins Tuesday evening with a strong ~583 dam
high located across Northern Ontario and the Upper Great Lakes.
This high works to suppress an upper level low/trough south as it
progresses eastward into the Ohio Valley. Meanwhile, eastern
Kentucky sits on the cool, northern side of a stalled frontal
boundary draped across Tennessee, North Carolina, and the Deep
South. Between the stalled front to our south and multiple
perturbations rotating around the approaching upper level low, the
area should see rounds of showers and thunderstorms Tuesday
evening and Wednesday. This could lead to isolated instances of
flash flooding before the main trough axis finally shifts south
and east on Thursday.

From Thursday onward, the upper-level trough amplifies and becomes
a closed low off the East Coast. As the trough axis shifts east
of the Commonwealth, cooler and much drier air arrives. Under
persistent northerly flow and surface high pressure, seasonably
cool weather takes hold: an extended period of daytime highs in
the 60s-70s and nighttime lows in the 40s-50s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 810 AM EDT MON SEP 21 2026

Mainly VFR conditions are noted across eastern Kentucky south of
I-64 at TAF issuance. The exceptions are the typical river valley
fog and a couple of isolated thunderstorms over the Big Sandy
Basin. Near/north of I-64, a low stratus deck, associated with a
cold front, has crept in from the north and impacted IOB and SYM.
The river valley fog should lift quickly by 14Z. There is a
similar expectation for the low stratus near and north of I-64 but
forecaster confidence is fairly low. Otherwise, mainly VFR
conditions are expected through about 18Z outside of any isolated
convection. Convection is expected to become more widespread after
18Z as it blossoms along/ahead the southward sagging cold front.
Widespread low stratus and fog is expected tonight behind the
boundary. Light winds will become southwesterly and increase with
daytime heating to 3 to 7 kts after 15z, veering northerly later
the day and evening behind the front. Gusty and erratic winds will
be possible with any showers and/or thunderstorms in the
afternoon and evening.

&&

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

&&

$$

SHORT TERM...GEERTSON
LONG TERM...GINNICK/GEERTSON
AVIATION...GEERTSON