Flash Flood Warning 74, NWS Jackson, KY

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
318 PM EDT Wed Sep 23 2026

.KEY MESSAGES...

- Showers and thunderstorms bring the risk of localized heavy rain
  and flash flooding this afternoon and evening.

- A Flood Watch is active from 1 PM to 10 PM today, mainly south
  of the Mountain Parkway and east of I-75.

- Isolated severe storms with damaging winds and large hail are
  possible in far southeastern Kentucky this afternoon and evening.

- Dry, cool weather settles in Thursday through the weekend
  before temperatures moderate early next week.

&&

.UPDATE...
Issued at 935 AM EDT WED SEP 23 2026

Some very isolated showers have been occurring. However, overall,
precip is a little slow to develop. Based on obs and latest model
guidance, have slowed down the uptick in POPs. Have also adjusted
sky cover to show more range, with overcast skies in many places
which carry further into the day.

&&

.SHORT TERM...(Today through Thursday)
Issued at 514 AM EDT WED SEP 23 2026

Damp and seasonably cool conditions are in place across eastern
Kentucky early this morning, with fog noted in many places and
temperatures ranging through the lower to mid 60s. The low cloud
cover is due to weak, moist northerly upslope flow in the lowest
levels on the western side of an inverted lee-side surface trough in
place just west of the Appalachian Mountain spine from roughly
Atlanta to Knoxville and Huntington. A broader analysis shows
eastern Kentucky along the southern periphery of an expansive
~1036 mb high pressure system centered over southern Quebec,
Maine, and Atlantic Canada. Looking aloft, a very weak ~580 dam low
is drifting across northern Illinois, while an ~586 dam
upper-level ridge is centered north of Lake Superior.

The aforementioned surface high becomes more centered over Atlantic
Canada today. In response, the lee-side trough along the western
slopes of the Appalachians will propagate slightly westward to sit
more directly over eastern Kentucky. As that westward shift occurs,
locations east of the trough axis will see winds veer from
northerly to easterly, causing low stratus trapped across much of
the area to break up under a weak downslope flow regime. The
trough axis then effectively becomes a nearly stationary
convergence zone directly over eastern Kentucky this afternoon and
evening. At the same time, the aforementioned upper-level low
will sink southeast to near Cincinnati this evening, bringing
positive differential vorticity advection forcing. Cyclonic flow
around this low will also maintain PWATs in the 1.25 to 1.50 inch
range over eastern Kentucky, with surface dew points remaining in
the lower to mid 60s. Sunshine, though likely limited, will
readily build instability over the lee trough, with RAP13 guidance
supporting 500 to 1500 J/kg of MLCAPE while upper-level flow
around the low supports 20 to 25 kts of EBWD (25 to 35 kts of
sfc-6km shear), sufficient for semi-organized multicells. Equilibrium
level (EL) heights will likely be the lowest we have seen in
quite some time, about 9 km AGL, so while those CAPE values sound
low, the model CAPE profile thickness is actually quite decent.
Additionally, relatively straight and long hodographs in the mid-
to upper-levels of the cloud-bearing layer should be supportive
of hail with stronger convective cores. SPC has noted this
potential along with a marginally severe wind threat over far
southeastern Kentucky (where the shear and instability parameter space
is expected to align most ideally) in a Day 1 Marginal Risk (1/5)
Severe Weather Outlook. Convection will not take long to fire
once heating begins, as the atmosphere will not really be capped
and LFCs will likely remain very low.

Of greater concern, though, will be the potential for excessive
rainfall. Steering-level winds will tend to push convective cells
from southwest to northeast, but easterly low-level flow could
tend to favor directing outflows westward. This presents an
environment for potential back-building and training of convection
repeatedly over the same locations. While PWATs are not all that
impressive, efficient rain processes could still be in play as
warm cloud layer depths will be ~10,000-12,000 ft deep. Additionally,
soils have been compromised across much of southeastern Kentucky
over the last few days by prior rainfall. Given all of these
factors, a Flood Watch has been hoisted from 1 PM this afternoon
until 10 PM this evening over a footprint nearly coincident with
WPC's Slight Risk (2/4) ERO. Within the Flood Watch area, CAM
output shows highly variable rainfall amounts of 0.1 to 3.0 inches
in the 24-hour HREF LPMM ending 12Z Thursday. Some of the
individual HREF/REF members are putting out isolated rainfall
bullseyes of more than 5 inches, but without clear spatial
consistency from run-to-run and model-to-model. Outside of the
Flood Watch, there could still be heavy rainfall (a Marginal Risk
(1/4) ERO remains in those areas) and perhaps even isolated flash
flooding, but CAM guidance on average is much less bullish about
high-end rainfall amounts for the time being. However, trends
will need to be monitored throughout the day to assess any need
for potential expansions of the Flood Watch.

Shower and thunderstorm activity will gradually taper off during
the first half of tonight as instability wanes and heights aloft
begin to rise, with the upper-level low drifting across eastern
Kentucky and West Virginia and departing toward the Carolinas.
That low will continue to deepen on Thursday as it moves to a
position off the Outer Banks. Meanwhile, drier deep northerly
flow in its wake will cause PWATs to fall through the day. There
could still be just enough moisture and weak instability for a
shower over the Cumberland River Basin during daylight hours, but
most locations should see increasing sunshine and slowly drying
dew points on a northeasterly breeze through the day.

In sensible weather terms, look for low clouds and fog to gradually
lift and break up a bit this morning before sunshine self-destructs
into scattered to numerous showers and thunderstorms. Some of
those showers and thunderstorms could become persistent and
produce flash flooding, especially near and south of the Mountain
Parkway and east of I-75. An isolated instance of large hail or
damaging thunderstorm wind gusts cannot be ruled out as well with
the strongest storms. It should be slightly warmer for most
places than yesterday, with high temperatures ranging from around
70F in the north to the mid 70s in the south. For tonight, showers
and thunderstorms slowly diminish, leaving behind a mix of clouds
and some fog. Temperatures dip back into the mid 50s northeast to
lower 60s southwest. Looking ahead to Thursday, it should be
partly to mostly sunny with only a stray shower possible in the
south, with high temperatures reaching the upper 60s northeast to
mid 70s southwest.

.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 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 318 PM EDT WED SEP 23 2026

Largely MVFR conditions were present to start the period, with a
smattering of VFR near the VA border, and IFR north of the
Mountain Parkway. There were also showers and thunderstorms
affecting some locations, especially near the VA border and from
around KFGX to KSJS, bringing localized IFR or worse conditions.

Varying conditions are expected to last into the night, but
largely settling on MVFR and IFR, along with showers at times and
a few thunderstorms. Precipitation should mostly taper off
overnight, but gradual improvement in conditions is not expected
until the day on Thursday.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 PM EDT this evening for KYZ069-080-085>088-
107>120.

&&

UPDATE...HAL
SHORT TERM...GEERTSON
LONG TERM...FAGAN
AVIATION...HAL

Hazardous Weather Outlook
National Weather Service Jackson KY
307 AM EDT Wed Sep 23 2026

KYZ044-050>052-058>060-068-079-083-084-104-106-240715-
Fleming-Montgomery-Bath-Rowan-Estill-Powell-Menifee-Rockcastle-
Pulaski-Wayne-McCreary-Elliott-Morgan-
307 AM EDT Wed Sep 23 2026

This Hazardous Weather Outlook is for a portion of eastern Kentucky.

.DAY ONE...Today and tonight.

Isolated to scattered thunderstorms are expected, mainly this
afternoon and evening. A few of these storms could produce strong
winds, small hail, and locally heavy rainfall.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

KYZ069-080-085>088-107>120-240715-
Jackson-Laurel-Whitley-Knox-Bell-Harlan-Johnson-Wolfe-Magoffin-Floyd-
Lee-Breathitt-Knott-Owsley-Perry-Clay-Leslie-Letcher-Martin-Pike-
307 AM EDT Wed Sep 23 2026

...FLOOD WATCH IN EFFECT FROM 1 PM EDT THIS AFTERNOON THROUGH THIS
EVENING...

This Hazardous Weather Outlook is for a portion of eastern Kentucky.

.DAY ONE...Today and tonight.

Scattered to numerous thunderstorms are expected, mainly this
afternoon and evening. A few of these storms could produce damaging
winds, large hail, and heavy rainfall. Locations impacted by repeated
rounds of heavy rainfall could experience flash flooding.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report any instances of wind damage,
large hail, and flash flooding this afternoon and evening.

GEERTSON