Area Forecast Discussion
Issued by NWS Louisville, KY

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168
FXUS63 KLMK 101035
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
635 AM EDT Thu Jul 10 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Patchy fog will be possible early this morning. A few stray
  showers are also possible mainly east of I-65.

* Warm and humid conditions continue into the weekend, with
  additional shower and storm chances for Saturday and especially
  Sunday as a cold front approaches the area. Severe weather is
  not expected.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 300 AM EDT Thu Jul 10 2025

Things are mostly quiet this morning, although a couple of issues to
discuss. First off, still hanging onto a few showers and rumbles of
thunder early this morning. One cluster is down toward the Lake
Cumberland region, and the other is over southern IN and northern
KY. Both are slowly moving ESE, and will handle with some iso
mention in the pre-dawn hours. The other issue is patchy fog
development. So far, obs and nighttime microphysics imagery are
showing transient and patchy fog development. Will continue to
monitor obs this morning, but patchy fog mention in the
grids/forecast should cover it.

Baggy troughiness will continue over our area today, although most
of the trough axis will be east of our area. As a result, only
expect isolated to widely scattered coverage today, and this will
mainly be east of I-65. Have some isolated chances up to along the
Ohio River, but these will generally be less than 20%. As far as
storm mode goes, should be the same story, different day. Any storm
that does develop will be in the presence of very weak deep layer
shear, and relatively poor mid level lapse rates. As a result, only
pulse modes will be expected with brief heavy rainfall, and a gusty
of wind with any collapsing updrafts. Outside of the meager precip
chances, should see a good amount of sunshine combined with a steady
SW wind. The end result will be warmer temps in the upper 80s and
low 90s.

Convection should wane around and after sunset with the loss of
heating. Mild overnight lows are expected with low mostly in the 70
to 75 degree range. Another decent fog signal is possible later
tonight under good radiational cooling conditions, and moist low
levels.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 300 AM EDT Thu Jul 10 2025

Friday - Sunday...

Weak zonal flow aloft will be in place on Friday, but overall there
doesn`t appear to be much of a triggering mechanism in place to
focus storm development. In addition, some forecast sounding data
shows a subsidence inversion around H7. Moderate instability is
expected to develop this day, and will likely see at least some
isolated development once convective temps are reached, but overall
looking for pretty minimal coverage of slow moving pulse storm
modes. Look for temps peaking in the upper 80s and low 90s with
partly sunny skies and a steady SW wind.

Saturday and especially Sunday should see a trend toward better
storm coverage peaking each afternoon and early evening. This will
occur as central CONUS troughing begins to sag into our area,
bringing a bit more of a focus for storm triggering. Sunday will
also feature a surface cold front dropping into our area, so this is
the highest confidence day for storm coverage, and will continue
mention of 60-70% chances this day. The hottest day of the weekend
should be Saturday with most highs in the lower 90s. By Sunday,
expect a couple degrees lower given increased storm coverage and sky
cover.

Monday is lower confidence, but will definitely have to leave shower
and storm chances in as some data suggests the front and baggy upper
trough will linger for one more day. If this does play out, coverage
will likely be highest across our southern and eastern portions of
the CWA. Highs are back in the upper 80s to near 90 by this time as
the front has some minimal influence on the area.

Tuesday - Wednesday...

Lower confidence for the mid week portion of the forecast as models
try to build a brief upper ridge over the SE CONUS. The problem is
that our region appears to be on the northern periphery of this
feature, and could subject us to continued diurnally driven shower
and storm chances. The stronger westerlies will be displaced just a
bit to our NW, but close enough that they could provide some
triggering influence into our area. For now, will just forecast warm
temperatures in the upper 80s and low 90s with some isolated to
widely scattered shower and storm chances.

&&

.AVIATION /12Z TAFS THROUGH 18Z FRIDAY/...
Issued at 634 AM EDT Thu Jul 10 2025

Currently seeing mix of stratus and fog at LEX and HNB, otherwise
the remaining sites are VFR. Both LEX and HNB are down near or below
minimums and this will likely persist through 9 or 10 AM EDT. Could
have a period here this morning where some MVFR or even brief IFR
stratus does impact the other sites, but will stay mostly optimistic
as surface heating will commence soon and should help mitigate too
much additional stratus development.

Should return to VFR at all sites by late morning to midday with a
light to steady SW to W surface wind. Winds go calm or light and
variable around sunset tonight with another shot at some restricting
fog. Have already started to hint at this for a couple of the sites
for later tonight.

&&

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

&&

$$

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