318
FXUS63 KJKL 091316
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
916 AM EDT Wed Jul 9 2025

.KEY MESSAGES...

- There is an elevated concern for high water and isolated flash
  flooding across the area today into tonight due to torrential
  downpours and possible training.

- High temperatures will be near normal through the week as
  humidity increases.

- Chances for shower and storms persist through the upcoming
  weekend, mainly during each afternoon and evening.

&&

.UPDATE...
Issued at 851 AM EDT WED JUL 9 2025

An area of light showers, with embedded small moderate elements,
is lifting northeast across the the Eastern Kentucky Coalfields
and Southeast Bluegrass at update time. There is sufficient weak
instability for a rumble of thunder with the strongest updrafts as
well. Expectation is for overall convective coverage and
intensity to increase heading through the day, coincident with
the diurnal destabilization cycle and the approach of a sluggish
500 hPa trough from the Mid-Mississippi Valley. Deep layer uni-
directional flow and PWATs nearing 2.0" along with efficient, deep
warm layer rain processes will support torrential downpours (and
possible training), leading to an increased concern for high water
and isolated flash flooding. Much of the forecast area east of a
Morehead-to-Jackson-to-Harlan line is under a Slight Risk for
excessive rainfall with a Marginal Risk elsewhere. For most
areas, rainfall amounts are expected to vary widely from mere
hundredths up to 2 inches. However, bullseye maximums in the CAM
members are supportive of isolated amounts of 2-4+ inches where
convection is most persistent.

UPDATE Issued at 1245 AM EDT WED JUL 9 2025

No significant changes were made to the forecast with mainly just
the inclusion of the latest obs and trends for the T/Td/Sky grids
and a touch up to the PoPs per current radar and CAMs guidance
through the night. These adjustments have been sent to the NDFD
and web servers along with a freshening of the zones, HWO, and
SAFs.

UPDATE Issued at 925 PM EDT TUE JUL 8 2025

01Z sfc analysis shows weak high pressure just off to the east of
the state. This is doing little to prevent the diurnal cycle of
convection from dominating the weather for our area. As such the
bulk of the activity is on the way out with some lingering cells
still down near the Virginia border. Currently temperatures are
running in the upper 70s and lower 80s. Meanwhile, amid light
winds away from any convection, dewpoints are generally in the
sticky low 70s. Have updated the forecast mainly to add in the
latest obs and trends for the T/Td/Sky grids but also to fine
tune the PoPs through the rest of the night per the latest radar
and CAMs guidance. These minor adjustments have been sent to the
NDFD and web servers along with a freshening of the zones, HWO,
and SAFs.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 255 PM EDT TUE JUL 8 2025

A seasonably hot and muggy early July afternoon is underway over
eastern Kentucky as a weak cold front sags into the area. This
cold front is roughly located from Vanceburg southwestward to
Lexington, then westward through Louisville. In the moderately
unstable (1,500-2,000 J/kg) environment ahead of the boundary,
scattered showers and thunderstorms have developed north of the
Mountain Parkway as of 2:45 PM EDT, and isolated activity has
begun developing further southeast. Through the remainder of the
afternoon and early evening, anticipate that the convection will
continue expanding in coverage and become more focused on the
eastern half of the JKL CWA. While the vast majority of the
convection should be of the garden variety, a few of the strongest
cells could produce gusty winds. Additionally, any location
affected by multiple heavy showers and thunderstorms could develop
isolated localized high water issues.

This unsettled weather pattern will persist through the short-
term period as a 500 hPa trough, extending from Northern Ontario
to over the Ozarks, drifts east to roughly James Bay to the Lower
Ohio Valley by sunrise Thursday. At the surface, the
aforementioned cold front is forecast to stall over Eastern
Kentucky this evening/tonight and dissipate. A subtle surface low-
pressure system ahead of the incoming 500 hPa trough will then
pass over the Great Lakes Wednesday into early Thursday and drop
another cold front toward eastern Kentucky by Thursday morning.
The combination of weak perturbations passing through the
troughing aloft and diurnal destabilization will favor scattered
to numerous shower and thunderstorm development again on
Wednesday. The lack of shear will limit the severe weather threat
to marginally strong wind gusts. The threat for isolated localized
high water issues will return on Wednesday afternoon as well,
particularly in locations affected by the most persistent
convection.

Sensible weather will feature continued scattered to numerous
showers and thunderstorms, reaching maximum coverage late this
afternoon and early evening. Some of these thunderstorms could
produce torrential downpours. Wednesdays temperatures will peak in
the mid-80s to near 90 degrees. Shower and thunderstorm activity
will wane quickly after sunset with only a low-end isolated shower
threat overnight. It will be mild and muggy with lows in the
mid-60s to around 70 degrees. Wednesday and Wednesday night will
feature similar temperatures and humidity levels. Fog is probable
each night, especially in favored valley locales and where
rainfall occurs late in the day, conditional upon partial
clearing.

.LONG TERM...(Thursday through Tuesday)
Issued at 425 PM EDT TUE JUL 8 2025

The long period is expected to begin with an upper level ridging
centered in the western Atlantic near Bermuda with a trough off
the southeast U.S. coast, troughing extending from Quebec across
the eastern Great Lakes to the Lower oH Valley to the Arklatex
region, with another upper level ridge centered near the CA and
Mexican border and extending from the southwest Conus into the
Pacific. At that point, a shortwave trough is expected to be in
the MN to IA vicinity with a stronger shortwave extending from an
upper low in northern Canada to the interior Northwest/northern
Rockies. At the surface, an area of low pressure should initially
be over the eastern Great Lakes vicinity with a frontal zone east
to off the New England/Northeast U.S. coast with the trailing
cold front toward the OH Valley region, but likely north of the OH
River and then west to the mid MS valley and portions of the
Central to northern Plains/Dakotas. Another sfc low centered in
the Manitoba vicinity should be in place ahead of the troughing in
western Canada.

For Thursday to Friday night, the axis of troughing at 500 mb
should shift north and northeast of the Lower OH Valley and
eastern KY from Thursday to Thursday night as upper troughing
moves toward the Maritimes and northeast. The next upstream
shortwave may move from the upper MS Valley vicinity to the Great
Lakes and generally pass north of eastern KY on Friday with
generally rising heights at 500 mb progged across eastern KY at
that point. Further west and southwest, upper level ridging
should encompass much of the western Conus and become centered a
bit further west off the CA to Baja coast. Meanwhile through
initially from central Canada to the Northwest Conus should move
east to the Hudson Bay to western Ontario region to portions of
the Northern and Central Plains to upper MS Valley. As this occurs
the boundary initially north and northwest of eastern KY should
sag a bit south into the Mid Atlantic states to portions of the OH
Valley though likely remaining north of the OH River through
Thursday into Friday. Though as troughing works across portions
of Canada and toward parts of the Northern Plains and Central
Conus that boundary should lift north and northeast of eastern KY
as a warm front with a sfc low organizing in the Plains and
tracking toward the Upper MS Valley/western Great Lakes with the
trailing frontal zone extending to the mid MS Valley to Southern
Plains at that point. With the rising heights from the Southeast
and into parts of the Appalachians during this timeframe, a sfc
ridge of high pressure is anticipated to build from the northeast
Gulf to the Southeast and Southern Appalachians during this
timeframe. With the rising height trend at 500 mb from Thursday to
Friday, Friday should be the warmer of the two days. The initial
trough/shortwave crossing the region should help to fire largely
diurnally driven convection for Thursday while the next trough
passing generally north with the frontal zone in the vicinity
should lead to some additional at least scattered convection on
Friday also likely peaking during the afternoon and evening.

Saturday to Sunday night, upper troughing is progged to move east
across Ontario to Quebec, the Great Lakes and OH Valley to the
Northeast to Mid Atlantic with upper ridging building into the
Southeast as the weekend progresses and remains in place from the
eastern Pacific to the western Conus. Additional troughing in
between the ridging is generally expected to develop from the
Central to southern Plains Sunday to Sunday night. At the surface,
low pressure should trek across the Northern Great Lakes to
Ontario and Quebec while the weakening trailing cold front moves
to the Central to eastern Great Lakes and the OH Valley region and
becomes diffuse by the end of the weekend. Additional rounds of
convection are anticipated across eastern KY during this timeframe
as well. There is a general consensus of a slight max in
convective probabilistic guidance from the GEFS and ENS for
Saturday across eastern KY. However, shear is expected to remain
limited this weekend as it will be this week and into early next
week and thereby limiting the potential for any organized
stronger convection. Highs over the weekend should be near normal
with a general peak in convection anticipated each afternoon and
evening though with the trough moving into and across the area,
some convection cannot be ruled out on Saturday night and into
late Sunday evening or Sunday night.

During the Monday to Tuesday timeframe, guidance has rising
heights 500 mb heights from the Southeast into the OH Valley, TN
Valley, and portions of the Appalachians while the axis of weak
troughing between that ridging and ridging from the Southwest
Conus to the eastern Pacific is over portions of the Plains/Central
Conus. This upper ridging with a ridge of sfc high pressure from
the northeast Gulf across the Southeast to the mid Atlantic should
result in a warming trend with more in the way of capping compared
to earlier in the long term period. The result should be near or
below average mainly diurnally driven pops for mid July with high
temperatures trending above normal by Tuesday to near or in excess
of the 90 degree mark for many locales.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 630 AM EDT WED JUL 9 2025

Any fog should burn off quickly by 13z at the sites with VFR
conditions likely for the morning and afternoon. There is a
chance of scattered thunderstorms this afternoon however
confidence is not high enough to go above a prob30 group at this
time. In any storm there is the potential for briefly much reduced
aviation conditions. Winds will generally be under 10 kts through
the period, except locally stronger and erratic near
thunderstorms. Another night of MVFR to potentially IFR vis with
fog could develop Wednesday night into Thursday morning.

&&

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

&&

$$

UPDATE...GEERTSON
SHORT TERM...GEERTSON
LONG TERM...JP
AVIATION...WFO SGF