977
FXUS63 KJKL 220932
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
532 AM EDT Sat Aug 22 2026

.KEY MESSAGES...

- Another cold front will bring a possibility of showers and
  thunderstorms to the area today.

- 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 then arrive to start
  the new week, with mainly dry weather.

&&

.SHORT TERM...(Today through Sunday)
Issued at 510 AM EDT SAT AUG 22 2026

Early this morning a closed upper level low was located in the
vicinity of the southwestern portions of Lake Huron with an upper
trough extending south and southeast across the Great Lakes to the
OH valley as well as the TN Valley and Southern Appalachians/Southeast
Conus. Meanwhile, an upper level ridge was centered in the Four
Corners region vicinity while an upper low was off the coast of
the Pacific Northwest. An initial shortwave was east of the
Appalachians while a second was moving across the Central Great
Lakes to Lower OH Valley region with yet a third shortwave
upstream from the western Great Lakes into parts of the Upper MS
Valley. At the surface, a quasi stationary front was well and
east of eastern KY from the Carolinas to the Gulf coast states to
the Southern Plains. A rather weak ridge of sfc high pressure was
located from the Ozarks vicinity into the Lower OH Valley in
between this baroclinic zone to the south and a cold front
extending from a sfc low in the UP of MI/Lake Superior to the mid
MS Valley to Central Plains. Clear skies, lingering low level
moisture with mid to upper 60s dewpoints, and light winds
associated with the sfc ridging has allowed rather extensive fog
formation overnight and this has become dense in several locations
even outside of the typical deeper valleys as of 5 AM EDT. An SPS
has been issued for this through 930 AM EDT.

Today and tonight, the shortwave currently working across the
Lower OH Valley region should cross the area through midday to
early afternoon with mainly some passing clouds for eastern KY.
However, the shortwave further upstream will move into the Central
Great Lakes to Lower OH Valley during the afternoon to early
evening. This will be preceded by the upstream cold front sweeping
across western and central sections of the Commonwealth as the
sfc low moves to the Lake Huron/Ontario vicinity. Once fog lifts
and dissipates within about 3 hours of sunrise, solar insolation
should result in highs mainly in the mid to upper 80s across
eastern KY, with 70s above 2500 feet. Southwest flow ahead of the
front should keep mixed dewpoints in the mid to upper 60s on
average. Cooling aloft from the approaching shortwave and daytime
heating should yield moderate instability 1500 to 2500 J/kg MLCAPE
with roughly 2000 to 3000 J/kg MUCAPE per 06Z RAP with at least
20 to 25KT of bulk shear. Unidirectional shear could support some
hail up to around quarter size though mid level lapse rates of
6C/km or less should be a limiting factor. Strong to locally
damaging wind gusts will be the primary hazard from isolated to
scattered convection that may organize into a couple of clusters
or line segments. Several recent HRRR runs have a few wind gusts
as high as 40 to 50KT the JKL CWA vicinity with late afternoon to
early evening convection. SPC has placed most of the area in a
Slight Risk for this and this has been highlighted in the HWO and
will also be highlighted in social media and weatherstory posts.
The shortwave shifts east of the area by late in the evening with
the cold front moving across the Appalachians and should result in
showers diminishing in all locations by midnight. Fog formation
should again occur, with valleys and locations that pick up more
substantial rainfall over the next 18 hours most favored for
potentially dense areas.

A sfc ridge of high pressure extending from Manitoba and Ontario
to the mid MS Valley during the evening will begin to build into
the area late tonight. This will be followed by a gradual trend in
500 mb heights on Sunday as the sfc ridge builds into the Lower
OH Valley and parts of the TN Valley as well as Southern
Appalachians. This will usher in an airmass more typical of a
month from now with 850 mb temperatures trending down a couple of
degrees C and dewpoints dropping off about 10 degrees mainly into
the mid to upper 50s as PW drops to the 0.65 to 0.95 inch range or
5th to 20th percentile range per 00Z HREF mean.

.LONG TERM...(Sunday night through Friday)
Issued at 400 AM EDT SAT AUG 22 2026

At the start of the long term period, the main story will be pleasant
weather more reminiscent of early fall than late August. Upper
level troughing will sit over the eastern CONUS, with a relatively
vertically stacked low pressure system over Ontario. Meanwhile,
to the southwest of the forecast area, upper level ridging will be
centered over the Southern High Plains. At the surface, high
pressure will sit over the Midwest, with winds generally light and
northwesterly across eastern Kentucky; this will work to maintain
the cooler and drier postfrontal air mass to begin the week.
These light winds and a weak pressure gradient across the area
will also allow for a modest ridge valley temperature split
overnight Sunday into Monday morning, with typical valley fog
formation. MOS guidance could be a bit aggressive with overnight
lows for some spots, given lingering moisture, and low 50s for the
coldest spots may be overdone. For most or all locations, low
temperatures will likely range from the mid 50s in valley
locations to the upper 50s or around 60 on the ridgetops. During
the day on Monday, the upper level ridge will expand eastward
somewhat. Associated height rises across the Ohio Valley should
work to keep the forecast area dry, with temperatures rising into
the upper 70s to low 80s. Thankfully, continued northwesterly
winds will keep dewpoints blissfully low in the mid 50s.
Overnight, low temperatures will again fall into the 50s, with a
similar modest ridge valley temperature split and another night of
river valley fog.

On Tuesday, forecast uncertainty increases somewhat. The upper level
trough axis will be well east of the area, with eastern Kentucky
in a region of northwest flow aloft. Many models depict a
shortwave traversing this flow, with fairly substantial spatial
and timing differences; at present, the most likely outcome is
that, at best, this energy delivers a glancing blow to the
forecast area, relegating any rain chances to Tennessee. However,
some deterministic model runs do suggest that an isolated shower
or storm could be possible in our southwestern counties. Even so,
a drier solution currently appears far more likely, and NBM PoPs
are accordingly very low.

More widespread rain chances may return to the forecast on
Wednesday as a surface low originally over Oklahoma translates
northeastward. A warm front associated with this low will attempt
to lift towards the area; however, a cold front extending from
another surface low over the Upper Midwest will loom to the west
of the forecast area. Given the expected eastward progression of
this cold front, there is significant uncertainty regarding how
far north the warm front can progress before it is overtaken.
Broadly, Wednesday and Thursday will feature increased moisture
and a chance of showers and storms; however, any forecast details
will remain dependent on the location, progression, and timing of
these boundaries, and forecast uncertainty is very high at this
time.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 235 AM EDT SAT AUG 22 2026

Fog has formed in the valleys, especially south of KIOB and KSYM
and it had begun to spread to near KLOZ as of issuance time. With
a deepening nocturnal inversion, this may lift into most or all of
the remaining TAF sites, at least briefly, between 08Z to 12Z with
MVFR to IFR if not lower reductions at times. Fog should lift and
dissipate between 12Z and 14Z and give way to cumulus development
by 16Z. A cold front and disturbance will approach during peak
heating and result in isolated to scattered convection between
about 17Z and 01Z. Some of the storms could contain strong to
damaging wind gusts and some gustier winds were included in a
PROB30 group for KIOB and KSYM although PROB30 groups for thunder
were included for the remaining TAF locations for a few hours
between 18Z and 00Z. Winds will be light and variable to begin the
period, but become WSW to W at 5 to 10KT between 15Z and 00Z.
Winds will trend to the northwest behind the front to end the
period and slacken. Strong gusts as previously noted in excess of
30KT are possible with any thunderstorms.

&&

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

&&

$$

SHORT TERM...JP
LONG TERM...HEF
AVIATION...JP