605
FXUS63 KJKL 211930
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
330 PM EDT Fri Aug 21 2026

.KEY MESSAGES...

- A series of cold fronts will bring a possibility of showers and
  thunderstorms to the area at times through Saturday.

- Some storms on Saturday afternoon and evening could produce
  strong to locally damaging wind gusts and even some hail.

- Noticeably cooler and less humid air will arrive to start the
  new week, with mainly dry weather.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 330 PM EDT FRI AUG 21 2026

Puffy cumulus are bubbling up across eastern Kentucky this
afternoon, with a few of them maturing into widely scattered
showers and even a few isolated thunderstorms. That aside,
temperatures are on the mild side for late August, with readings
ranging in the low to mid 80s outside of convection. At the surface,
a weak wave of low pressure is traversing far southeast Kentucky
along a wavy cold frontal boundary. Aloft, 500 hPa troughing is
in place over the Great Lakes and Ohio Valley with an embedded
vort max just upstream over central Kentucky. A second notable 500
hPa vort max is dropping into the trough from northwestern
Ontario. It is attended by a weak surface low over Lake Superior
from which a cold front sweeps out an arc, first southwestward to
along the Iowa/Nebraska border and then west-northwest to along
the northern Rockies.

The ongoing isolated to scattered convection is likely to increase
slightly in coverage over the next hour or two before gradually
diminishing with the loss of daytime heating as we head through the
evening. As the wavy frontal boundary finally sinks well south of
the area, clearing skies, light winds, and ample moisture will set
the stage for renewed radiational fog formation overnight,
especially in typical sheltered valley locations, though at least
patchy fog may develop elsewhere. It will be seasonable, with
temperatures dipping back into the mid 60s in most spots.

Looking ahead to Saturday, the second vort max will carve a deeper
parent trough as it presses into the Lower and Mid-Ohio Valley.
This will be attended by the surface cold front, which is
currently favored in short-range model guidance to pass through
eastern Kentucky during the ~5 PM to midnight timeframe. Ahead of
this boundary and upper-level disturbance, strengthening flow
aloft will yield 30 to 40 kts of EBWD while good heating is
favored to build 2000 to 3000 J/kg of MUCAPE Saturday afternoon.
With ample dry air aloft and DCAPE values near or over 1000 J/kg,
downdrafts capable of producing strong to damaging winds will be
possible on an isolated scale. Additionally, the CAPE profile is
well-proportioned within the hail growth zone and hodographs are
relatively straight. Therefore, if any of the stronger cells can
adopt supercellular characteristics, isolated hail is also a
reasonable secondary possibility. Accordingly, SPC has maintained
a Marginal Risk (1/5) for damaging winds and large hail across
nearly all of the JKL CWA. Heading into Saturday evening and
night, convection should diminish as the front and upper-level
disturbance depart. In their wake, clearing skies and light winds
will once again set the stage for at least some fog in the valleys,
though weak low-level northwest flow will be a mitigating factor.
Saturday night`s low temperatures are forecast to range in the
low to mid 60s.

.LONG TERM...(Sunday through Friday)
Issued at 330 PM EDT FRI AUG 21 2026

The long term period will start with a relatively comfortable air
mass in place, by August standards. Surface high pressure supplying
the cooler and drier air should be ridging from western Ontario to
the lower Ohio Valley, while low pressure (surface and aloft) is
just north of the Great Lakes. The upper trough surrounding the low
will cover most of the eastern CONUS. Our lowest dew points from
this air mass are forecast from Monday into Tuesday, with readings
in the 50s, also allowing for lows in that range. In fact, the NBM
and MEXMOS are only a couple degrees off the record of 55 at JKL on
the 25th.

The low and the trough weaken by midweek as they drift east, and a
warming trend gets underway locally as geopotential heights rise.
The forecast then gets messier moving into the late week time frame.
Another upper low or trough is expected to move east southeast to
southeast Ontario, which will deepening a larger scale upper trough
over the eastern CONUS again. This supports a cold front to move
southeast through the Midwest. There is not agreement on the timing
of this front to arrive here, or on the surface pattern setting up
in advance. At this point, only a generalized forecast is practical,
with an increase in moisture/dew points and POP ahead of the front
late in the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 213 PM EDT FRI AUG 21 2026

An extensive cumulus field had developed over most of eastern
Kentucky by the 18Z TAF issuance. Continued development into
isolated to scattered showers and storms is likely through early
evening, mainly south of I-64. While conditions should be
primarily VFR, brief reductions are possible at any terminals
impacted by convection. Convection will dissipate this evening
with the loss of diurnal heating. Thereafter, valley fog should
again develop and this may affect a few of the TAF sites during
the ~06Z to 12Z timeframe. As for winds, outside of any storms,
winds will generally be light and variable.

&&

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

&&

$$

SHORT TERM...GEERTSON
LONG TERM...HAL
AVIATION...GEERTSON/JP