123
FXUS63 KLMK 011848
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
248 PM EDT Mon Sep 1 2025

.KEY MESSAGES...

* Isolated daytime shower and thunderstorm chances return across
  southern KY this afternoon and evening, and then all other
  locations through mid to late week.

* Best chance for .5" to 1" of rainfall will be across southern and
  eastern KY through Thursday.

* A strong front will bring another shot of cool and dry air to the
  region late week through the weekend.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 248 PM EDT Mon Sep 1 2025

Another pleasant day for most of the CWA as temperatures sit in the
low to mid 80s under partly to mostly sunny skies. We do have a few
showers down across the Lake Cumberland region, and these will
continue to trigger off of remnant outflow, and meander at a very
slow pace through the afternoon and early evening. Overall,
instability is modest, and is currently ranging between 500-1000
J/KG along and south of the inverted surface trough. Given virtually
no deep layer shear and very meager mid level lapse rates, any
updraft will struggle. Perhaps a few lightning strikes along with
brief moderate rain and briefly gusty winds are possible.

Convection should largely die off with the loss of heating through
early evening, although cannot completely rule out a stray shower
across southern KY through the overnight as remnant outflow floats
around and subtle shortwave energy begins to dig into the TN Valley.
Look for overnight lows mostly in the 55 to 60 degree range,
although a few spots in the south will only fall to the low 60s.

The surface boundary over our SE today makes a little more progress
northwestward tomorrow where more isolated to widely scattered
showers and a few storms are expected to develop.As a result, will
bring isolated pops up to along the Ohio River by later
afternoon/early evening, with scattered coverage across southern KY.
Lows should mostly be in the low to mid 80s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 248 PM EDT Mon Sep 1 2025

Tuesday - Thursday...

Inverted surface trough slowly lifts NW across our area Tuesday into
Wednesday, which gradually opens up our entire CWA to be on the
unstable side of the boundary. As a result, will continue isolated
to widely scattered shower and storm chances through that time
period. May also get a bit of additional help from a subtle
shortwave rotating through the TN Valley during this stretch, but
overall the bulk of any shower storm coverage should be across
central and southern KY (especially southern KY), with very little,
if any, coverage across southern IN. Most temps should peak in the
75 to 80 degree range Tuesday, with Wednesday a bit warmer in the
upper 70s and low 80s.

By later Wednesday night into Thursday, focus shifts upstream to a
potent shortwave trough axis associated with a deeply anomalous
closed low over the upper Great Lakes region. Good forcing and some
deep moisture pooling ahead of this feature should bring the best
coverage of showers and a few storms Thursday morning into to the
day. Will keep likely/numerous wording going for that time period as
the upper trough axis and associated cold front slide through the
area. Overall, expected precipitation through Thursday should range
between .5" to 1" south of the Parkways. Farther north, total
rainfall will likely only reach the .1" to .25" range across
southern IN, and .25" to .5" range north of the Parkways.
Probabilities for anything over 1" are only 20-30% and this is
confined to far southern KY according to the 01/00z LREF. Will
mention that the overall shear profile does improve on Thursday
morning ahead of the front, however any concern for a strong/severe
storm seems to be limited by the lack of any near surface based
instability. Will continue to monitor as forecast sounding currently
show a notable low level inversion around that time.

Thursday Night - Monday...

The surface cold front and upper trough axis look to be clean
through our CWA by Thursday night with surface high pressure
building in its wake. The late week/weekend time frame should be
dry, but confidence is a bit lower due to some model differences
handling another clipper-like shortwave rotating through later
Friday night into Saturday. This could bring some light
precipitation, or at the very least another reinforcing shot of cool
air. The temps will be the biggest story with highs on Saturday and
Sunday only in the mid and upper 70s. Meanwhile, Sunday morning lows
will be in the mid to upper 40s across southern IN, and in the upper
40s to low 50s across KY. Temps do begin recovering by Monday into
the upper 70s and low 80s, but still below normal for this time of
year.

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 154 PM EDT Mon Sep 1 2025

VFR conditions are expected to remain through the forecast
period. Look for continued light to steady NE surface winds, perhaps
even a gust or two up around 15 mph for SDF/LEX. Otherwise, few-sct
high based cu will be most common at BWG/RGA/LEX with the best
chance at an isolated shower near BWG this afternoon or early
evening.

&&

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

&&

$$

SHORT TERM...BJS
LONG TERM...BJS
AVIATION...BJS