858
FXUS63 KLMK 192312
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
712 PM EDT Sat Sep 19 2026

...Updated Aviation Discussion...

.KEY MESSAGES...

* Unseasonably hot weather will continue for much of the area
  through at least Sunday. Barring any early day thunderstorms, heat
  indices will top out in the mid 90s to around 105 (highest
  southwest) each afternoon.

* There is a 30-50% chance (highest northeast) for showers and
  storms late this afternoon and evening, with slightly lower
  chances tomorrow. Locally damaging wind gusts, frequent lightning,
  and heavy rainfall may accompany the strongest storms.

* A weather system will bring higher rain chances (50-70%) Monday
  into Tuesday, followed by a cool down to more seasonable
  temperatures (highs in the 70s, lows in the 50s) by the second
  half of week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 332 PM EDT Sat Sep 19 2026

It has been a dry but hot day for our area so far, with temps
climbing into the lower 90s, and isolated storms noted all around
our area. SPC maintains the Marginal Risk for severe storms through
this afternoon and evening. More details below.

===== Unseasonably Hot Temperatures Continue =====

KY Mesonet shows temperatures in the 90s across the region, with
Butler county currently reporting 100F over a 61F dewpoint.
Definitely seeing some mixing going on this afternoon to lower those
dewpoints some, but most heat indices are in the upper 90s to lower
100s. A similar forecast is expected tomorrow, with the entire area
at least reaching the low 90s. While we may not reach advisory
criteria again tomorrow, will plan to extend the Heat Advisory one
more day due to potential impacts given the temps in the middle of
September. We are nearly 10-15 degrees above normal. The record max
temp for both today and tomorrow is 96F, so those records will be in
jeopardy.


===== Marginal Risk for Severe Weather Today =====

There is a low-end risk (level 1 of 5) for some isolated to
scattered strong to severe storms this afternoon and early evening.
GOES satellite imagery and LVX hi-res shows a boundary sneaking into
our area from central IN, which will be the focus area for storms to
fire off from. Given the strong heating today, we`ve been able to
realize over 1500 J/kg of MLCAPE, though wind shear is very weak.
Model soundings show large CAPE profiles, with DCAPE around 1000
J/kg, and PWATs around 1.6". There is a chance for scattered storms
to pop up in this environment, which would be slow moving heavy
downpours, with damaging wind gusts and frequent lightning as the
main concerns.

The Marginal Risk for tomorrow has been trimmed to now include
mainly our counties north of I-64. Coverage for tomorrow looks to be
even less that what is possible today, so mainly a stray storm
chance for Sunday.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 332 PM EDT Sat Sep 19 2026

===== Monday - Wednesday =====

Sfc low pressure will be sitting across the area on Monday, which
will support at least some isolated to scattered showers and storms
across the area. In addition to those chances, Monday features quite
a tricky temperature forecast, with a north-south gradient expected
on where that sfc low sits. There is potential for us to see temps
in the upper 70s near Madison IN, to lower 90s across south-central
KY Monday afternoon. Any severe potential will be limited to the
south side of the low where better heating will be, so overall
severe risk appears low at this time.

For Tuesday and Wednesday, we`ll be in a post-frontal cooler airmass
with an upper trough overhead, which will bring a welcoming change
in temps to the region. Highs on Tuesday still could be split north
to south, with mid-70s north of the WK/BG Pkwys, and mid--80s to the
south. However, by Wednesday, we begin to see more fall-like temps
with highs in the 70s and overnight lows in the 50s. We`ll still
have some precip chances during this time due to broad lift from the
trough, but a gradual exit to the east is expect by Wednesday night.

===== Late Next Week =====

The upper pattern will amplify over late next week with the upper
trough deepening into an upper low over the East Coast, and ridging
building across the Central Plains. This will place the Ohio Valley
in a more persistent NW flow, which will result in amplifying our
cooler pattern. The result could be more days with highs in the 70s
and overnight lows in the 50s. Dry weather is expected through the
end of the week with sfc high pressure moving across the Great Lakes
region.

&&

.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 712 PM EDT Sat Sep 19 2026

VFR conditions are expected through the upcoming TAF period.  Winds
will start off out of the southwest this evening but back to the
southeast overnight before returning to the southwest after dawn
Sunday.  Mainly dry weather is expected for the day on Sunday,
though we could a period of gusty winds between 20/16-20/22Z with
the winds calming back down toward sunset.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Heat Advisory until 8 PM EDT /7 PM CDT/ Sunday for KYZ023>028-
     053-061>063-070>076.
IN...Heat Advisory until 8 PM EDT /7 PM CDT/ Sunday for INZ083-089.

&&

$$

SHORT TERM...CJP
LONG TERM....CJP
AVIATION.....MJ