206
FXUS63 KLMK 110529
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
129 AM EDT Tue Aug 11 2026

.KEY MESSAGES...

* A Heat Advisory is in effect for areas west of a Jasper, IN to
  Scottsville, KY line on Tuesday afternoon and evening. Max heat
  index values around 105 degrees are expected.

* A northwest flow pattern aloft will take residence across the
  region for much of the upcoming work week with clusters of showers
  and storms impacting portions of the central and eastern Ohio
  Valley. Across west-central Kentucky, dry and hot conditions are
  expected.

* Storms that develop will likely be strong/severe with torrential
  rainfall, intense lightning, and the potential for damaging winds.
  The highest risk of severe weather for later tonight through
  Tuesday night will be across southeastern Indiana and into
  portions of far northern Kentucky.

* Multiple clusters and/or wave of storms will likely train across
  portions of IN/OH and KY this week. This will lead to excessive
  rainfall and flash flooding. Locally, the highest risk for
  flooding would be across our northeastern portions of the forecast
  area (SE IN and the Bluegrass region).

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 256 PM EDT Mon Aug 10 2026

Things are quiet across the CWA at this hour as we sit between upper
ridging to our south, and low amplitude NW flow to our north. The
current pattern features enough of a H85 subsidence inversion along
with the lack of any notable triggers to likely keep us dry the rest
of today and tonight. We will have to watch the upstream MCS over
OH/WV, as some data indicates re-development could occur on its
western flank later this evening and then backbuild SW into our CWA
later tonight. The bulk of these solutions is offered by NAM based
CAMs, and so far, that model has been too far west and south with
its MCS development, so will put that in the "less likely" scenario
category for now. Still, something to monitor.

Temperatures have surged into the upper 80s and low 90s across the
area, and with dew points running well into the 70s, especially west
of I-65 we are seeing some heat indices creep into the 100 to around
105F range. Elected not to go with a Heat Advisory for counties west
of I-65 today as we`ll likely only peak there for an hour or two
this afternoon, however have issued a Heat Advisory for tomorrow for
locations along and west of a Jasper, IN down to Scottsville, KY
line.

In addition to the heat and humidity for tomorrow, focus will
continue to be on potential MCS activity. It is possible that an MCS
flirts with our NE CWA by mid to late Tuesday morning, however this
would likely be in a weakened state, and is only low confidence on
affecting our area at all. The bigger focus/concern will be with an
expected stronger MCS by early evening, perhaps lasting into the
overnight. This complex would be triggered by a shortwave embedded
in the NW flow aloft, that most of the models seem to agree on.
Given that we will be strongly unstable (ML CAPE 3000-4000 J/KG)
combined with at least 30-40 knots of mid to upper level flow that
setup seems right for a developing upstream MCS to forward propagate
into our area thanks to favorable shear for updraft/cold pool
balance. This system would carry mainly a damaging wind threat
(perhaps widespread if the cold pool really gets going), however a
Flash Flood threat could develop if western portions of the MCS
stall and become more parallel to the upper flow. Considered a Flood
Watch for our NE CWA, however confidence isn`t quite high enough to
take it that far SW just yet. Thanks to ILN/JKL for collaboration on
that.

The other area of uncertainty is how deep into the night, and how
far west any MCS activity might make it. It is possible that an
early damaging wind threat in the evening, transitions to a Flash
Flood threat deeper into Tuesday night thanks to storms backbuilding
against the upper flow. The 10/12z HREF 48 Hr QPF Max ensemble
member does suggest some very high localized amounts, however the
PMM data isn`t quite on board with the extreme values. It does
suggest some pockets of 3-4" in localized areas and that is likely
what we will continue to message unless confidence changes either
way.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 256 PM EDT Mon Aug 10 2026

Wednesday - Friday Night...

Upper ridging will hold over south central CONUS through mid to late
week, and we`ll continue to see a NW flow pattern over our region on
the NE periphery of the upper ridge. This will put us in the game
for continue MCS potential through late week, however much will
depend on the evolution of each previous system, and how far south
and west into the ridge each convectively reinforced boundary / cold
pool can make it. For now based on pattern recognition, our NE half
of the CWA looks to be the most likely to experience a severe
weather threat (primarily damaging winds), along with potential
flash flooding if repeated rounds of convection start to add up
and/or, the western flank of any MCS stalls and becomes more
parallel to the upper flow.

Across our SW CWA, we are expected to be deeper into the upper
ridge, and therefore expect an overall hotter and drier pattern.
Although, a strong MCS could wreck this scenario at any point mid to
late week. For now, feel the more likely scenario will be better
chances of getting into the low to mid 90s each day. These temps
combined with dew points expected to be in the low and mid 70s will
create some heat index values peaking around 100 to 105 degrees. It
is possible we could add a tier or two of counties to a Heat
Advisory along and west of I-65, but may have to take this a day at
a time as low confidence will continue with regard to MCS activity,
and the potential to get a cold pool push or convective cloud debris
wrecking a temp forecast.

Saturday - Monday...

The upper ridge looks to build heading into the weekend, and center
more over the Ozarks. As this occurs, it will assert more influence
into our region, which should lead to a hotter/drier type of setup
for the weekend. The good news is that it should lessen the threat
of MCS activity across our area, however it will likely come with
hotter overall temps. Current NBM suggest low to mid 90s by Sunday.
Some Heat Advisory headlines would likely be needed, at least for a
portion of our area. Along and west of I-65 would be the best
candidate.

By Monday, the upper ridge may flatten out over our area and
retrograde back to the west. As this occurs, a surface frontal
boundary trailing from a NE CONUS system may drop into our northern
CWA. We could be back in the game for more MCS activity around this
time, but not too confident this far out. Temps would likely settle
back closer to normal highs for this time of year.

&&

.AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 128 AM EDT Tue Aug 11 2026

A weakening ridge of high pressure should maintain VFR conditions at
all of the airfields through mid afternoon, though there will be a
low (15-20%) chance of a stray morning storm at RGA. More numerous
storms will develop over Indiana during the late afternoon and may
(50-70% chance) drop southeast to affect all of the terminals except
perhaps BWG during the evening into early overnight period. While
confidence is low on timing, prob30 groups highlight the period of
greatest concern at each terminal. Outside of storms, winds will
blow out of the southwest, with gusts upwards of 20 kt at times
during the afternoon.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Heat Advisory from 11 AM this morning to 8 PM CDT this evening
     for KYZ023-026-061-070>073.
IN...Heat Advisory from noon EDT /11 AM CDT/ today to 9 PM EDT /8
    PM CDT/ this evening for INZ083-089.

&&

$$

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