Severe Thunderstorm Warning 261, NWS Louisville, KY

Area Forecast Discussion
National Weather Service Louisville KY
340 PM EDT Wed Jun 18 2025

.KEY MESSAGES...

* Strong to severe storms through this evening, with all severe
  hazards on the table. Damaging winds are the main threat, and
  highest confidence in severe storms along and west of Interstate
  65. Localized flooding also possible where the heaviest rain
  falls.

* Scattered showers remain possible into Thursday.

* Mainly dry weather Friday through the weekend, with building heat
  and oppressive humidity continuing well into next week. Highs in
  the 90s with heat indices near 100 Sunday through Tuesday.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 340 PM EDT Wed Jun 18 2025

===== Enhanced Risk for Severe Storms Through This Evening =====

A line of severe thunderstorms is currently working its way into the
Wabash Valley, and over the next several hours will be moving into a
very favorable environment. Copious amounts of moisture available
with sfc dewpoints in the mid 70s and PWAT values around 2 inches.
Deep-layer shear supports storm organization, and sfc winds in some
areas are backed to around 170, which will enhance low-level shear
to support rotating storms in at least our Indiana counties, as well
as northern portions of central Kentucky.

Tornado Watch 435 extends eastward roughly to the I-65 corridor,
though the tornado threat likely drops off fairly sharply near or
south of the Western Kentucky Parkway. The overall severe threat
will likely extend farther east, but storms are not expected to
reach the Frankfort and Lexington areas until roughly 8-9 PM EDT.

Main hazard will be damaging winds, especially as convection grows
upscale into a squall line. Some risk of spin-up tornadoes will
persist, but will require bowing along the line to re-orient
perpendicular to the shear vector.

After sunset instability will be lost, and storms will weaken at
some point as they run out of fuel. As a result the main source of
uncertainty is how long storm intensity will be maintained.
Scattered showers and a few thunderstorms could continue overnight,
but severe threat will be minimal as the atmosphere will be worked
over.

Another potential threat this evening will be flash flooding, as 1-
hr FFG is around 1 inch in the locations that have seen heavy
rainfall within the last few days. Localized 2-3 inch rainfall
amounts will be possible where storm clustering or training occurs,
so will need to monitor heavy precip trends closely.

Scattered showers and a few T-storms possible Thursday as the sfc
front lingers over the area. However, no additional severe wx is
expected after the line passes tonight.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 340 PM EDT Wed Jun 18 2025

For Friday and into the weekend, anomalous upper ridging will build
across the central US, keeping a dry forecast for the end of the
week and reinforcing the warm air advection pattern. This will
result in above normal temps for the weekend and into early next
week.

Just how hot we get remains a bit uncertain, given how saturated our
ground is from all the recent rain, and very green vegetation.
Despite this uncertainty on ambient temperatures, the bigger story
may be the combination of well above normal temperatures and the
humid airmass. Dewpoints are forecast to return to the 70s by the
weekend, and if our temperatures are able to hit 90, that would
yield heat indices in the mid to upper 90s and approaching 100.

These above normal temps and humid dewpoints will continue into
early next week with broad high pressure across the eastern half of
the US.

&&

.AVIATION /18Z TAFS THROUGH 00Z FRIDAY/...
Issued at 122 PM EDT Wed Jun 18 2025

MVFR cigs initially will lift just barely into VFR by mid-afternoon
with continued heating. The deeper mixing will also bring down
increasingly frequent 20+ kt wind gusts from the SW.

Convection picks up late afternoon, beginning 20-21Z at HNB, pushing
into SDF 22-23Z, and finally LEX/RGA around 01Z. Will use a PROB30
to capture MVFR cig/vis, but brief IFR conditions are possible in
the strongest part of the storms. Could keep lingering -SHRA
overnight, especially BWG and LEX, but higher confidence in MVFR
cigs below 2000 feet. Sfc cold front comes in Thu morning, shifting
winds to due west, with continued low cigs.

&&

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

&&

SHORT TERM...RAS
LONG TERM...RAS/CJP
AVIATION...RAS

Hazardous Weather Outlook
National Weather Service Louisville KY
453 AM EDT Wed Jun 18 2025

INZ076>079-083-084-089>092-KYZ023>043-045>049-053>057-061>067-
070>078-081-082-190900-
Orange-Washington IN-Scott IN-Jefferson IN-Dubois-Crawford-Perry-
Harrison IN-Floyd-Clark IN-Hancock-Breckinridge-Meade-Ohio-Grayson-
Hardin-Bullitt-Jefferson-Oldham-Trimble-Henry-Shelby-Franklin-
Scott KY-Harrison KY-Spencer-Anderson-Woodford-Fayette-Bourbon-
Nicholas-Nelson-Washington KY-Mercer-Jessamine-Clark KY-Larue-Marion-
Boyle-Garrard-Madison-Butler-Edmonson-Hart-Green-Taylor-Casey-
Lincoln-Logan-Warren-Simpson-Allen-Barren-Monroe-Metcalfe-Adair-
Russell-Cumberland-Clinton-
453 AM EDT Wed Jun 18 2025 /353 AM CDT Wed Jun 18 2025/

This Hazardous Weather Outlook is for portions of southern Indiana
and central Kentucky.

.DAY ONE...Today and tonight.

There is a risk for strong to severe thunderstorms late this
afternoon and into the evening hours. All severe hazards are on the
table, but the primary threat will be damaging winds. Continued
heavy rainfall later tonight could result in localized flooding.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed.

&&

More information, along with other weather, hydrological and
climate information can be found, at weather.gov/louisville.

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