JKL issues Area Forecast Discussion (AFD) at Sep 24, 1:53 AM EDT704
FXUS63 KJKL 240553
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
153 AM EDT Thu Sep 24 2026
.KEY MESSAGES...
- Showers and a stray thunderstorm will continue to be possible
through the night but the threat of additional flooding has
ended.
- Dry, cool weather settles in Thursday and last through early
next week.
&&
.UPDATE...
Issued at 1020 PM EDT WED SEP 23 2026
One last pesky thunderstorm is slowly dragging itself out of the
the area through Harlan County. However, this area is pretty
saturated so that flash flooding remains a distinct threat for
parts of that county until it finally exits. Nevertheless, the
Flood Watch was allowed to expire at 10 pm with 90%+ of the area
seeing only light showers at times through the night. A stray
thunderstorm cannot be ruled out but most places will not see one.
Areas of fog and low clouds remain possible, as well. Have
adjusted the PoPs per the latest radar returns and CAMs guidance
through dawn, Thursday. In addition, have included the latest obs
and trends for the T/Td/Sky grids. These adjustments have been
sent to the NDFD and web servers along with a freshening of the
HWO, SAFs, and zones.
UPDATE Issued at 735 PM EDT WED SEP 23 2026
23Z sfc analysis shows an inverted trough slowly exiting to the
east of the state. When combined with a passing shortwave trough
overhead, this is still capable of giving southeast parts of
Kentucky some excessive rainfall and flash flooding. Accordingly,
the Flood Watch continues through 10 pm with most activity
looking to fade to light showers after that point. Warming IR
cloud tops supports this idea, as well as the latest CAMs guidance
and now waning instability. Otherwise, temperatures are fairly
uniform across eastern Kentucky, generally in the mid 60s - along
with dewpoints - while winds are mainly from the north to
northeast at 10 mph or less. Have updated the forecast primarily
to extend the higher PoPs into the night in the far eastern parts
of the area per the latest radar loops and CAMs consensus
guidance. Did also add in the most recent obs and trends for the
T/Td/Sky grids. These adjustments have been sent to the NDFD and
web servers along with a freshening of the SAFs, FFA, and zones.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 517 PM EDT WED SEP 23 2026
A complicated scenario is in place late this afternoon. Sprawling,
very strong high pressure is centered over southern Quebec, and an
induced inverted/lee surface trough is along the western side of
the Appalachians in the flow around the high. The cooler air mass
has been making better progress down the eastern side of the
mountains, with remnants of our old (warmer, more moist) air mass
stuck here on the immediate western side. Meanwhile, an upper low
is approaching us from the northwest. Geopotential height falls
and cooling aloft with the approaching upper level low are
supporting convection which has become widespread in southeast
Kentucky. Movement has been slow and chaotic, with persistent
cells producing locally flooding rains.
Convection will persist into this evening, perhaps
moving/developing further northwest. As this happens, remaining
convection in our east will become more elevated above a
developing cold pool. As the upper low moves southeast over the
central Appalachians just to or northeast tonight, support will
wane and drying will progress into the JKL forecast area from the
west and begin to cut off precip. However, models suggest it may
linger into Thursday in our eastern counties before the upper low
finally cleanly departs to our southeast.
Clearing skies finally arrive thursday afternoon and evening.
This allows for radiational cooling on Thursday night. There will
still be a bit of a pressure gradient across the forecast area,
promoting northeast to east low level flow with cold air
advection. This will fight against decoupling. However, suspect
that at least the deeper valleys will decouple, which will allow
for the coolest temperatures we've seen in a while, below 50
degrees. Where decoupling occurs, valley fog is likely, especially
where the ground is wet from recent rain.
.LONG TERM...(Friday through Wednesday)
Issued at 249 PM EDT WED SEP 23 2026
Overall, the long term period will be characterized by cool and
quiet weather, owing to a fairly persistent midlevel ridge west of
the forecast area. At the start of the period, a vertically
stacked low will be located off of the North Carolina coast, with
a highly amplified ridge over the central CONUS. This low will
deepen as it lifts into the Northeast, blocking any eastward
progression of the ridge. Eastern Kentucky will find itself on the
western edge of northeastern troughing through at least the
weekend, with most guidance suggesting that this system will lift
far north into Canada by early next week. This will allow the
ridge axis to progress eastward, with the next major system not
approaching until the very end of the forecast period.
At the surface, this large scale pattern should keep weather cool
and dry through the weekend. Largely northeasterly winds around a
surface high over the Great Lakes will relegate dewpoints to the
40s, peaking in the mid 50s at their wettest. Even with mostly
clear skies each day, highs will range from the upper 60s to mid
70s. In short, it will finally feel less like summer and more like
fall. Overnight, clear skies and light winds will enable
efficient radiational cooling, with ridge valley splits expected
to develop. MOS guidance suggests temperatures will bottom out in
the low 40s in particularly sheltered valley locations on
Saturday, Sunday, and Monday mornings. Given that most guidance
agrees temperatures could fall into the mid 40s overnight (even
without considering terrain factors), this seems very feasible. It
may be time to get your jacket out.
By early next week, temperatures will warm somewhat as the ridge
expands eastward. Highs will climb into the low 80s in many
locations by Tuesday, although weather will still be dry. As of
now, the next rain chance looks to be Wednesday as a large scale
system approaches, but the details remain fuzzy this far out.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 153 AM EDT THU SEP 24 2026
Outside of some VFR over the Big Sandy, mainly MVFR to IFR stratus
ceilings with some patchy fog are noted across eastern Kentucky
at the 06Z TAF issuance. An inverted surface trough lingers over
far eastern Kentucky and could support a few more showers or even
a rumble of thunder through daybreak -- a TEMPO group was
included with the SJS TAF to account for this concern. Sustained
improvement in the ceilings is not expected until during the day
on Thursday when the trough finally begins to fade and drier air
filters in on a northeasterly flow. Winds will generally be around
5 kts or less from the northeast through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...GREIF
SHORT TERM...HAL
LONG TERM...FAGAN
AVIATION...GEERTSON
Source:
JKL issues Area Forecast Discussion (AFD) at Sep 24, 1:53 AM EDT---------------
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