734
FXUS63 KLMK 121035
AFDLMK

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

...Updated Aviation and Near-Term Forecast...

.KEY MESSAGES...

* A few strong to severe storms possible later this afternoon and
  evening, especially across southern Indiana and northern Kentucky.
  Locally damaging winds, small hail, and brief heavy rainfall are
  the main threats.

* Warm and humid with continued chances of showers and storms
  through Sunday. Gusty winds, heavy rainfall and lightning will be
  the main impacts but some storms could produce small hail and
  gusty damaging winds. Locally heavy rainfall amounts are
  possible.


* 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 634 AM EDT Sat Jul 12 2025

The outflow boundary from overnight upstream convection that
diminished over IL/MO has now made its way into our NW CWA. This
feature will continue to push SE through our area, and it may spark
a few isolated showers or a storm this morning. Models indicate
there could be isolated to widely scattered coverage mainly along
and east of I-65 by midday into the early afternoon. The second
round of storms expected by late afternoon through the evening will
likely have better potential to be stronger.

Went ahead and updated pops to start a slightly earlier trend for
precip chances.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 258 AM EDT Sat Jul 12 2025

Things are quiet across the CWA early this morning, and that will
continue for much of the morning, if not all of it. Thereafter,
focus shifts upstream to an approaching cold front and the
reintroduction of scattered showers and thunderstorms for the
afternoon through late evening. Currently, a weakened complex is
dissipating across central IL/MO, and we`ll likely only see some
upper sky cover/anvil debris from it. The other feature we`ll have
to keep an eye on is the remnant outflow that is currently making
steady SE progress toward our area. This may indeed be a focus for
initiation later today once we destabilize. Different hi-res models
have different thoughts about that. For instance, the 12/00z 3 km
Nam has a pretty reasonable solution of scattered showers and storms
initiating to over the center of our CWA between Noon and 2 PM EDT
on that remnant outflow, and then a secondary area of convection
developing much later in the afternoon and early evening ahead of
the approaching cool front and pre-frontal trough.

Ahead of these features we do expect to destabilize fairly quickly
as temperatures reach into the upper 80s and low 90s amid low to mid
70s dew points. This should yield moderately unstable ML CAPE values
around 1500 to 2500 J/KG. Do expect we`ll see some stronger storms
given the amount of instability and a couple of triggering
mechanisms, however the limiting factor to a more organized severe
weather threat is the lack of deep layer shear. It only looks to be
around 15-20 knots in the 0-6km layer which would be sub par for
more sustained/organized updrafts. Still, given the amount of
instability and the potential for some water loaded microbursts
and/or a cold pool push from collapsing storms, do think a couple
severe thunderstorms warnings aren`t out of the question. Marginal
Risk covers the threat nicely, and the upgrade to a Slight Risk over
southern IN and far northern KY seems to mimic the 12/00z 3 KM Nam
fairly well. Given the plausibility of that scenario think it looks
pretty good. Right now, the biggest threat for severe storms looks
to be between 5 and 11 PM EDT.

Convection should diminish into the overnight, however given the
surface front still dropping into our area, can`t rule out a few
stray showers and storms overnight. Look for mild temps in the low
and mid 70s for most.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 258 AM EDT Sat Jul 12 2025

Sunday - Monday...

A baggy shortwave trough axis over the eastern CONUS will slowly
slide through Sunday. Meanwhile at the surface, a cool front will
slide into our area. Ahead of these features, moderate instability
on the order of 1500-2500 J/KG of ML CAPE is expected to develop.
This setup has plenty of ingredients for numerous showers and
thunderstorms in the moist and unstable atmosphere. There continues
to be a weak signal for deep layer shear only around 15-20 knots,
however do expect we could get a few pulse storms strong enough to
produce some gusty downburst winds, cloud to ground lighting, and
brief heavy rainfall. In fact, the bigger concern will likely be the
locally heavy rain threat given slow moving thunderstorms and PWATs
approaching 2" through the column. SPC dropping the Marginal Risk is
noted, although expect a couple of strong to severe storms can`t be
ruled out; especially given the little extra nudge of forcing
compared to our recent pulse environments from last week.

The upper trough axis slowly moves eastward by Monday, however the
weak surface front is left lagging across southern and eastern
portions of our CWA. As a result, will keep lingering pops in for
this area on Monday with highs a tick cooler in the upper 80s and
low 90s.

Tuesday - Friday...

The SE CONUS upper ridge tries to build in for the mid week time
frame, however a weak disturbance looks to ride the NW periphery of
that feature, and could bring additional showers and storms to our
area for Tuesday and Wednesday. From there, mainly diurnally driven
shower and storm chances are likely to continue into late week as
our region remains positioned on the northern fringes of the SE
CONUS ridge, and on the southern fringes of the stronger westerlies
associated with a zonal flow aloft pattern. This will keep us in
line for any weak triggering mechanisms embedded in the flow, and on
the edge of the upper ridge where the subsidence inversion is
weaker. All of this supports at least some diurnally driven shower
and storm chances each afternoon and evening. Temps will likely be
slightly above normal for this time of year with highs peaking in
the upper 80s and low 90s. Any early convection each day could knock
temps down, but will likely reach low 90s by early afternoon with
scattered PM storms providing some spotty relief from temps at times.

&&

.AVIATION /12Z TAFS THROUGH 18Z SUNDAY/...
Issued at 634 AM EDT Sat Jul 12 2025

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. A few showers or storms could pop by late
morning or early afternoon, but overall coverage/confidence is low
for this first round. Later in the afternoon and evening, expecting
scattered thunderstorms to develop ahead of an approaching cold
front. Some of those storms could be strong with gusty winds and
brief heavy rainfall. Kept Prob30s to cover that threat.

&&

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

&&

$$

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