548
FXUS63 KLMK 182032
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
432 PM EDT Mon Aug 18 2025

.KEY MESSAGES...

* Tomorrow, Heat index values of 100-105 are likely, mainly west of
  the I-65.

* A cold front will likely bring a little relief from the heat and
  increased thunderstorm chances Tuesday and Wednesday.

* Below normal temperatures expected for the second half of the
  weekend into next week.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 431 PM EDT Mon Aug 18 2025

Tonight, upper ridging remains centered over much of the CONUS.
At the surface, high pressure extending southwest out of Quebec will
continue pushing through the Lower Ohio Valley, keeping weather
quiet. Any remaining diurnal cumulus will dissipate early in the
night, leaving clear skies. Already light and variable winds ease
and become nearly calm. Radiative cooling will help temperatures
fall into the mid 60s to low 70s. This could result in some light
fog as temperatures near the dew point, mainly along the eastern CWA
border in the Bluegrass and Lake Cumberland regions.

Tomorrow, the day begins under mostly clear skies, but a cold front
approaching from the northwest will increase rain chances over
southern Indiana during the afternoon hours. Even if showers and
thunderstorms hold off until later in the afternoon, increased cloud
cover is expected along the boundary.

With highs expected to climb back into the low to mid 90s and dew
points in the upper 60s to mid 70s east of Interstate 65 and into
the low 70s to upper 70s west of 65, heat index values once again
cross 100 degrees, mainly west of Interstate 65. Currently, have the
highest isolated values of 105 in the forecast across southern
Indiana from Dubois to Clark Counties. This doesn`t paint a pretty
picture with what neighboring offices have out in current Heat
Advisories, plus any cloud cover or rain could limit warming in this
area. This is mainly being driven by the higher dew points from the
pooling of moisture with the incoming front. Farther south in
Kentucky, dew points are to be a little lower, reducing the heat
index values. Either way, it`s going to be another warm day.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 431 PM EDT Mon Aug 18 2025

Tuesday night, as the cold front continues to approach from the
northwest, several CAMs show better chances for scattered convection
to develop over southern Indiana before slowly working southeast
across central Kentucky. Early in the night, remaining instability
could help to get additional gusts to the surface, but the lack of
deep layer shear will help limit storm organization. As diurnal
warming is lost, gusts will become less likely as lapse rates become
more stable.

Wednesday, shower and thunderstorms chances remain as the front
slowly drops southeast through Kentucky. Guidance keeps better
chances over the southeastern CWA along a main axis of
precipitation, most areas are expected to see a mostly dry day with
afternoon and evening heating driving additional chances. The front
will bring slightly cooler temperatures with highs only making it to
near 90 for most through Saturday. Nightly lows will also see cooler
temperatures where 60s become more common than 70s across southern
Indiana and central Kentucky.

By Thursday, as a surface high gets pushed south towards the CWA,
the chances for precipitation decrease through Saturday before a
second cold front drops south through the CWA Saturday night. This
currently looks mostly dry, but noticeable cooling is expected. Highs
on Sunday and Monday are expected to only reach into the 80s with
dew points in the 50s.

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 221 PM EDT Mon Aug 18 2025

VFR conditions are expected through most of the forecast period.
For the rest of today, few to scattered cumulus will last into the
evening before clear skies return tonight. Winds will continue to be
on the lighter side, but somewhat variable. Tomorrow morning, light
fog is possible with the best chances being at RGA.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Heat Advisory until 7 PM CDT this evening for KYZ023-026-061-
     070>073.
IN...Heat Advisory until 8 PM EDT /7 PM CDT/ this evening for
     INZ083-089.

&&

$$

SHORT TERM...KDW
LONG TERM...KDW
AVIATION...KDW