565
FXUS63 KLMK 082325
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
725 PM EDT Tue Sep 8 2026

...Updated Aviation Discussion...

.KEY MESSAGES...

* Mostly dry and warmer today. A few light showers possible later
  this afternoon. Thunderstorms are not expected.

* The hottest day of the week will be Wednesday with highs in the
  low to mid 90s and peak heat indices in the low 100s along and
  west of I-65. A Heat Advisory has been issued for Wednesday
  afternoon.

* A cold front arrives Thursday morning with 80-90% chance of
  showers and a few storms possible. Fairly widespread rainfall
  between .5" - 1" is expected with locally higher amounts over 1.5"
  possible, especially along and north of I-64.

* This weekend is expected to remain active with multiple waves of
  showers and storms.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 255 PM EDT Tue Sep 8 2026

High pressure at the surface and strong ridging aloft has allowed
for temperatures to warm today into the upper 80s and low 90s.
Southwesterly flow has increased dew points into the upper 60s and
low 70s. Heat indices are in the upper 90s this afternoon. A broken
cumulus deck has developed and isolated, brief light showers will
continue through the afternoon. Showers will remain brief and are
not expected to intensify given the strong subsidence over the
region. This evening, low clouds will dissipate and southerly flow
will remain light. This will prevent efficient radiational cooling
tonight and temperatures will bottom out in the upper 60s over the
far east, valley areas and low-mid 70s elsewhere.

On Wednesday, the surface high pressure will push eastward and a
strong low pressure will begin to push into Great Lakes. This will
allow the pressure gradient over the Ohio Valley to tighten. Breezy
southwesterly winds sustained around 15mph and gusting up to 25-
30mph are expected through the afternoon. Given this impressive
pattern, temperatures tend to overachieve. Expecting to see highs in
the low-mid 90s. Dew points are expected to increase over the
region, which will place peak heat indices in the 95-105F range. A
bust potential for northern areas will be the potential for
increased cloud coverage and late afternoon showers and storms. A
Heat Advisory has been issued for Wednesday from Noon ET to 8PM ET.

Later in the afternoon and into the evening hours, a pre-frontal
trough is expected to push south into southern Indiana. Showers and
storms will be widespread along this trough. Instability will grow
in the afternoon and deep-layer shear of 25-30kts will support a few
storms. PWATs are expected to be 2.0-2.2 inches, which is at the max
of climatology for this time of year. Therefore, the main threat
will be water-loaded downbursts leading to gusty to damaging winds
and very heavy rainfall. Instability will wane quickly into the
evening hours. Though, the cold front and troughing will approach,
which will increase lift and shear. Additionally, a LLJ will set up
over the Ohio River and flow will run parallel to the front. As the
front stalls, this will likely create training showers and storms
through night and into the morning on Thursday. Given the dry
antecedent conditions, we can take quite a bit of water, though some
flooding may be possible. The threat for damaging winds will remain
over southern Indiana and the threat for flooding will extent south
to the Bluegrass Parkway. HREF LPMMs show a few swaths of 3 inches
of rainfall possible. Though the average rainfall will be around 0.5-
1 inches.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 255 PM EDT Tue Sep 8 2026

On Thursday, the front will practically stall over the region and
continued convergence along the front will keep widespread showers
and storms over the region. Later Thursday and into Friday, an upper
trough moves across the Ohio Valley and gives the surface front some
southward momentum. At this time, showers and storms will cease over
the northern half of the region and remain over the southern half
through Friday.

Beyond Friday, the front will remain in the region and the upper
pattern will remain active with multiple shortwaves moving over the
region. Periods of showers and storms are expected through the
weekend and into early next week. Ridging looks to build in from the
south early next week, which will lead to warmer than normal
temperatures.

&&

.AVIATION /00Z TAFS THROUGH 06Z THURSDAY/...
Issued at 724 PM EDT Tue Sep 8 2026

VFR will continue tonight with winds from the south. For tomorrow,
VFR conditions will remain, but expect our winds to increase after
sunrise, likely gusting to near 20kts through the afternoon hours.
By tomorrow evening, a cold front will approach the region, and
should begin to have increasing chances for precip just beyond the
forecast period.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Heat Advisory from noon EDT /11 AM CDT/ to 8 PM EDT /7 PM CDT/
     Wednesday for KYZ023>032-061-062-070>072.
IN...Heat Advisory from noon EDT /11 AM CDT/ to 8 PM EDT /7 PM CDT/
     Wednesday for INZ076>079-083-084-089>092.

&&

$$

SHORT TERM...SRW
LONG TERM...SRW
AVIATION...CJP