364
FXUS63 KLMK 071729
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
129 PM EDT Mon Sep 7 2026

...Updated Aviation Discussion...

.KEY MESSAGES...

* Dry and seasonable Labor Day expected with only a small chance of
  a shower or storm around the Lake Cumberland region by early
  evening.

* 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 west of I-65.

* A cold front arrives Thursday morning with 70-80% chance of
  showers and a few storms possible. Fairly widespread rainfall
  amounts between .25" and .5" are currently expected.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 241 AM EDT Mon Sep 7 2026

Things are quiet across the region at this hour with high pressure
centered over the eastern Great Lakes, extending influence into our
area. Light NE surface winds and a few upper clouds will continue
this morning. This will allow for lows mostly in the low and mid 60s
toward sunrise, although can`t rule out a few upper 50s across our
far NE. Light to steady NE/ENE winds continue today with plenty of
sunshine to go along with a few mid and upper clouds at times. Temps
should be a tick or two warmer than yesterday with max values mostly
in the 85 to 90 degree range.

Almost all of the area stays dry today, although will have to
continue mention of some isolated to widely scattered shower or
storm chances down near the Lake Cumberland region this evening.
Inverted surface trough looks to set up with dew points in the upper
60s to near 70 pooling in our far SE. This added low level moisture
will aid the development of a modest instability axis on the order
of 500-750 J/KG of ML CAPE, and could provide enough fuel for a few
showers and storms assuming the weak surface convergence is enough
of a trigger. Hi-res CAMs and other deterministic data suggests that
at least a few showers or storms will develop by early evening.
Overall, deep layer shear is weak so any storms would be pulse in
nature.

Other than that, dry conditions continue through early week with
upper ridging strengthening over the southern CONUS. This will allow
temperatures to continue trending upward as we move through Tuesday.
Another couple degree rise by then will allow for highs in the upper
80s to low 90s across the area.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 241 AM EDT Mon Sep 7 2026

Wednesday - Thursday Night...

The hottest day of the week looks to be Wednesday as upper ridging
continues to dominate the southern half of the CONUS. Meanwhile, a
steady SW surface flow will set up over our region between high
pressure centered off the mid Atlantic coast, and a strong surface
low over eastern Canada. In fact, the pressure gradient will be
quite impressive for this time of year, and looks like we could see
some 20-25 mph gusts from a very well mixed boundary layer. This
looks like a pattern where temps could overachieve, so like where
the NBM is toward the higher side of the guidance envelope, and
similar to the 90th percentile ECM temp guidance. Peak heat indices
could be a bit of a concern for Wednesday as they will likely reach
into the low 100s for a time. Expect afternoon mixing may lower dew
points enough through the afternoon to keep any Heat Advisory
headlines from being needed, but it will be close. Overall, low to
mid 90s expected for highs, with shower and storm chances holding
off until later Wednesday night into Thursday.

A cold front trailing from the aforementioned strong eastern Canada
surface low will approach for Thursday. Ahead of this feature,
fairly widespread coverage of showers and storms is anticipated to
drop into and through our region. Looks to be a fairly strong amount
of deep layer shear across the northern half of our CWA where 35-45
knots may be realized. Across southern KY, values would be weaker
and more in the 25-35 knot range. Weak to modest instability and
particularly weak mid level lapse rates could be the limiting factor
for whether any strong to severe storms will be possible, and timing
of the frontal passage on Thursday will have a lot to do with that.
Should fairly strong storms develop, then we may have to watch for a
bit of training as the deep layer flow will be nearly parallel to
the surface boundary. A few localized areas could see some higher
rain totals in this setup, but overall the expected widespread
rainfall between .25" and .5" for most will be welcome. Right now,
LREF probabilities of 1" or more drop off to 10-15% or less.

Friday - Sunday...

Things are expected to be a bit cooler and overall drier by Friday
as high pressure builds in behind the cold front. Perhaps a few
showers linger across our southern CWA, but will only keep low
chances in here. Temps settle back into the mid and upper 80s to end
the week, at least briefly. The overall dry pattern should continue
into the weekend although some weak troughing may allow for a few
non-zero shower or storm chances. Better chances for the upper ridge
to build back in by late weekend, and this will allow temps to rise
back into the upper 80s and low 90s if it occurs. Only low to medium
confidence in the weekend for now given some uncertainty in how the
upper pattern will evolve by this time.

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 129 PM EDT Mon Sep 7 2026

VFR conditions are expected through this forecast period. High
pressure will help to keep winds light and skies with a light Cu
field. Winds this afternoon will vary from the north-northeast to
the east around 4-9kts. In the evening, winds will relax to mostly
variable around 3-4kts. Around sunrise, winds will veer to the south
around 7-10kts.

&&

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

&&

$$

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