539
FXUS63 KLMK 080504
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
104 AM EDT Wed Oct 8 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

*  Rain will taper this evening, though a few isolated showers may
   linger into the nighttime hours tonight.

*  Cooler, more seasonal temperatures arrive tomorrow, continuing
   through the weekend. Dry conditions are expected through the
   weekend.

&&

.UPDATE...
Issued at 904 PM EDT Tue Oct 7 2025

Current KLVX Radar is showing a few isolated in a line stretching
from Jefferson Co. IN through Clark Co. IN southwest towards Grayson
Co. KY to Todd Co. KY.  These showers are much weaker than they were
before sunset but they are firing along the cold front that is
crossing central KY this evening. While most of the activity is
isolated in nature. given that these are firing along the boundary,
feel our current POPs look good through the rest of the evening and
overnight. Low stratus over central IN will drop southward overnight
along with low stratus currently over the eastern portion of our
CWA. Clouds and even some pocket of drizzle is possible through the
overnight and into the early morning hours but confidence is not
that high. Winds will also begin to increase out of the north, and
you can see this already occurring over in western KY per the
Kentucky Mesonet. The rest of the forecast looks to be on track and
any additional rain that may fall will not lead to any additional
flooding issues overnight.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 417 PM EDT Tue Oct 7 2025

This afternoon, sfc low pressure is tracking across central KY,
moving east as a broader sfc cold front sweeps through the region.
Ahead of the front, persistent 30-35 kt southerly flow in the low-to-
mid levels has led to PW values near 2" along and just ahead of the
sfc low center. Broad isentropic upglide, llvl convergence along an
effective warm front, and embedded convection has led to a band of
moderate to heavy showers and storms which has pushed along the I-64
corridor over the past 12 hours, bringing widespread rainfall
amounts in excess of 2" and a corridor of 4-6" of rain,
overperforming expectations. Across south central KY, rainfall
amounts have underperformed as a lack of an organizing boundary has
kept rain showers more scattered and kept precipitation totals at or
less than 1".

As we head through the rest of the afternoon, the heaviest rain
should push toward the Appalachians as winds swing around to the N
and NW with FROPA. Some scattering in the low stratus behind the
front has allowed for modest destabilization to occur as llvl lapse
rates steepen, with 1000-1500 J/kg SBCAPE developing across the
Wabash Valley. Scattered showers, and possibly an isolated storm,
will develop along the cold front, pushing off to the south and east
through the evening hours. Precipitation amounts with these showers
should be light enough as to not exacerbate ongoing flooding, with
QPF totals generally 0.25" or less.

Tonight, drier air will begin to work in as cold advection sets in
in the post-frontal environment. However, stubborn llvl moisture
will likely hang around in the form of a stratus layer overnight,
with this stratus not expected to clear from north to south until
Wednesday morning. This stratus layer may briefly be deep enough for
patchy drizzle or mist to form, especially across eastern portions
of the CWA. Otherwise, mostly dry conditions are expected tonight.
Temperatures should range from around 50 tomorrow morning across
southern IN to around 60 along the KY/TN border.

By sunrise Wednesday, low clouds should begin to scatter out, with
mostly sunny skies returning for all by early afternoon. A
seasonally strong pressure gradient in the wake of the cold front
should allow for robust cold advection into the area, keeping
temperatures in the low-to-mid 70s in spite of ample sunshine. N/NE
winds will be gusty at times, with sustained winds of around 10 to
15 mph and wind gusts to 25 mph expected late morning into the
afternoon.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 417 PM EDT Tue Oct 7 2025

Wednesday Night through Friday Night...

High pressure will settle just to the north of the region Wednesday
night into Thursday as drier northeasterly flow continues to filter
in behind the departing cold front. The cP air mass which moves into
the region should be the coolest one we`ve seen so far this fall,
sending temperatures below normal across the area for the end of the
week. The pressure gradient on the southern side of the high should
remain strong enough for breezy conditions to continue on Thursday,
with NE winds of 10-15 mph and gusts to 20 mph expected.

During the late week period, highs should range from the upper 60s
to the low-to-mid 70s with nighttime temperatures at least falling
into the 40s across the area. Thursday night has the greatest
potential for peak radiational cooling as winds will start to relax
and skies remain clear. With this forecast issuance, the typical
cooler spots in southern IN and the Bluegrass region of KY would be
expected to at least fall into the upper 30s, with a few mid 30s
possible in the coldest valleys. Increasing cloud cover should keep
temperatures slightly milder Friday night, but widespread 40s would
once again be expected.

Next Weekend and Early Next Week...

An upper level low pressure system will evolve into a closed low
over the Great Lakes region Friday into Friday night, gradually
sinking into the upper Ohio Valley and middle Appalachians over the
weekend. At the same time, upper level ridging will gradually shift
eastward from the southern Plains into the lower and mid-Mississippi
Valley by early next week. At the surface, a weak low pressure
system supported by the aforementioned closed low aloft will slide
across the Great Lakes Friday night into Saturday, with a weak cold
front dropping across the Ohio Valley during this time period.

While there should be weak moisture return ahead of this system, PW
values should remain below 1", and the combination of lacking
moisture and weak forcing will likely keep us dry through the
weekend. Temperatures will gradually increase through the period as
heights begin to increase. Highs are expected to be in the 70s with
low temperatures in the 40s and low 50s.

&&

.AVIATION /06Z TAFS THROUGH 12Z THURSDAY/...
Issued at 103 AM EDT Wed Oct 8 2025

With the cold front pushing through the area this morning, we will
continue to see restrictions to flight cats for a few more hours.
MVFR and IFR cigs will gradually ease over the coming hours, first
at SDF, then later for LEX and BWG. NW winds behind the front are
around 10kts, so fog potential with vis impacts will be rather low.
We`ll see improvements to VFR later this morning for all terminals,
with breezy winds becoming more NE by the afternoon. SKC and VFR is
expected by tonight.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.

&&

$$

UPDATE...BTN
SHORT TERM...CSG
LONG TERM...CSG
AVIATION...CJP