304
FXUS63 KLMK 120547
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
147 AM EDT Sat Jul 12 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Very warm and humid with chances of showers and storms over the
  weekend. Gusty winds, heavy rainfall and lightning will be the
  main impacts but some storms could produce small hail and gusty
  damaging winds.

* Remaining very warm and humid for most of next week with more
  scattered rain and storm chances each day with heavy rain, gusty
  winds and lightning.

&&

.UPDATE...
Issued at 948 PM EDT Fri Jul 11 2025

It is a quiet and warm evening across central KY and southern IN,
with temperatures in the upper 70s and low-to-mid 80s in most
locations at this time. Very isolated light radar returns continue
to pop up across the area; however, the previous forecast with
silent PoPs continues to look good as coverage is well below 15%.
For the rest of the tonight, temperatures will not be able to cool
as efficiently as previous nights, as a cold front approaching the
region from the NW will promote continued light southerly breezes
across the area. Any patchy fog should be limited to near bodies of
water and sheltered valleys. Ongoing thunderstorms along the front
will dissipate over the next few hours well before reaching the
area. As a result, expect a quiet, warm and muggy night, with
temperatures falling into the low-to-mid 70s by sunrise Saturday.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 324 PM EDT Fri Jul 11 2025

Thanks to the daytime heating and steep mid-level lapse rates, we`ve
some very isolated showers along with some embedded thunder develop
this afternoon. These showers/storms seem to be diminishing here
over the last few hours and may end up being mainly dry the rest of
the afternoon and into the evening. To play it safe, will continue a
a 10-20 percent chance for precip into the early evening. Main
threat is a brief heavy downpour and some slightly gusty winds.
Temperatures this afternoon remain in the upper 80s/low 90s with
dewpoints in the upper 60s/low 70s. As we go overnight it will
remain warm and muggy as lows will remain in the low/mid 70s but
will remain dry.

The forecast become a bit more active as the first in a series of
shortwave troughs works across the Great Lakes and the Ohio Valley
tomorrow afternoon evening. At the sfc, a cold front coming out of
the Upper Midwest and central plains will be working towards the
Ohio Valley. Ahead of these features we will see PWAT values climb
to  between 1.75" to 2", highs will once again be in the low/mid 90s
with dewpoints in the low/mid 70s allowing for fair amount of
instability of around 2000 J/kg, and low amounts of shear thanks to
a LLJ working over the area tomorrow afternoon and evening. This is
why SPC has the northern half of our CWA in a marginal or (1/5) for
severe weather. While this overall threat remains fairly low, the
main threat appears to be gusty winds around 60 mph, locally heavy
downpours and lightning.

&&

.LONG TERM /TONIGHT THROUGH FRIDAY/...
Issued at 324 PM EDT Fri Jul 11 2025

Cold front coming out of IL/IN Saturday night into Sunday will slow
and take its time approaching our CWA, as a second shortwave trough
works across the Great Lake and Ohio Valley during the day Sunday.
It will be another hot and humid day and with the proximity of the
cold front and the passing shortwave to our north, numerous
scattered showers and storms are possible in the afternoon. SPC also
has the western half of the CWA, from I-65 westward in a marginal
(1/5) risk for severe weather again for the possibility of gusty
winds. As the sfc boundary slows and become nearly stationary near
to just north of the Ohio River, strong moisture advection ahead of
the boundary will push PWAT values back to around and even over
2.00" late Sunday afternoon into the evening. Along with the gusty
winds, heavy downpours with possible localized flooding and
lightning will be the main threat with this activity.

Cold front will slowly work across southern IN/central KY during the
day Monday into Tuesday as ridging begins to strengthen over the
eastern US. Showers will remain scattered Monday afternoon and
temperatures will remain hot and humid. As the ridge strengthens over
the area on Tuesday highs will be rather warm into the low/mid 90s
with again diurnally driven scattered showers and storms for
Tuesday.

Wednesday through the end of the week will see the ridge over the
Ohio Valley and eastern US break down and flatten as a shortwave
trough ejects out of the Pacific Northwest on Tuesday and works
across the northern US into the Great Lakes by the end of the week.
This will continue the same kind of weather we`ve seen over the last
several days of highs in the 90s with muggy conditions and diurnally
driven convective towards the afternoon.

&&

.AVIATION /06Z TAFS THROUGH 12Z SUNDAY/...
Issued at 146 AM EDT Sat Jul 12 2025

Expecting a quiet early morning period to continue with light SSW
winds and a few mid level clouds. After sunrise, more steady SSW to
SW winds take hold with even some gusts around 20 mph in the
afternoon. Look for Few-Sct cumulus around 4-6 k feet as well. Later
in the afternoon and evening, expecting scattered thunderstorms to
develop ahead of an approaching cold front. Kept Prob30s to cover
that threat.

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...BTN
LONG TERM...BTN
AVIATION...BJS