Flash Flooding and Hail in Indiana, April 27, 2026

Area Forecast Discussion
National Weather Service Louisville KY
156 PM EDT Mon Apr 27 2026

...Updated Aviation Discussion...

.KEY MESSAGES...

* Some light rain is possible in our far SW communities.
  Otherwise, Monday will feature breezy conditions with wind gusts
  of 25-30 mph.

* Strong/severe thunderstorms are expected Monday evening and into
  Tuesday morning.  The highest risk of severe weather is in areas
  west of I-65 and decreases as you head east of the I-65 corridor.

* Another round of strong to severe storms is expected Tuesday
  evening and into the overnight. Damaging winds and large hail are
  the main severe threats.

* Temperatures cool Wednesday afternoon and will run below average
  through next weekend for late April/early May. Mostly dry weather
  is expected after Wednesday, with a slight chance for light rain
  on Friday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 408 AM EDT Mon Apr 27 2026

===== Monday - Tuesday Morning =====

In the early morning hours today a broken layer of high level clouds
is rolling in from the west. A cluster of storms over
central/southern MO is approaching our western border counties but
is moving into an unfavorable environment, collapsing as they draw
closer. We're monitoring how far these storms advance as it seems
our western counties, primarily those in the southwestern CWA near
Bowling Green, could see some light to moderate rain by sunrise.
These showers are not expected to make it beyond I-65, with PoPs
generally under 40% for the early morning.

Everyone else though remains dry with clouds around in the morning
and morning lows in the low to upper 50s, higher temps in the west
from increased cloud cover. Then we await the big weather maker for
Monday night. A strengthening shortwave will quickly eject north of
Lake Superior Monday afternoon, chasing after the left exit region
of an upper level jet. As the shortwave exits, it will kick off a
QLCS along a cold front over the plains. These storms though will be
moving away from their upper level support from the departing
shortwave and be supported by daytime instability, a slowing cold
front, and a low level jet through the day as they march eastwards.
As the Sun sets, instability decreases and mid to lower level
support will be weakening, causing these storms to gradually weaken
as they approach from our west. For our CWA the current setup
supports discrete cell formation ahead of the main QLCS that could
eventually blossom into a secondary line preceding the main event.
Despite the expected weakening, the main severe threat from these
storms can mix down strong winds from the LLJ overhead.
Additionally, a chance of a few tornadoes is possible, especially in
our far western border counties where the LLJ will be strongest as
the storms roll in.

The timing of these storms is key, along with any preceding
supercells/clusters of storms that could weaken the severe potential
of the main line. Right now, we think most of Monday
morning/afternoon remains dry with a broken-scattered cloud deck at
high levels in the morning lowering ahead of incoming storms. Highs
Monday afternoon will boost into the upper 70s to mid 80s despite
lingering cloud cover. SW wind gusts will increase from daytime
mixing with gusts ranging 20-30 MPH. The stronger wind gusts will
peak in the afternoon, and will remain gusty until storms roll
through. Western counties will be hit first, primarily by clusters
undergoing upscale growth forming a preceding line of storms by late
afternoon/early evening after 6 PM. Storms will progress eastward,
possibly forming two back-to-back lines by late evening along and
north of the Bluegrass. As the evening progresses, the severe threat
for damaging winds decreases with a loss of daytime heating and the
aforementioned loss of upper level support. The greatest severe
threat for damaging winds is west of I-65 with a small chance of a
tornado more favorable as you head west of Orange County, IN. Later
Monday night, these two lines of storms may eventually merge, or the
preceding line takes over with a decent moderate rain band following
the leading edge of storms. By Monday night, the cold front helping
to sweep the storms through will slow and eventually stall out over
our central CWA oriented SW-to-NE. The main line of storms will keep
moving SE towards our southern communities overnight meaning they
take the longest time to clear storms out.

Eventually, storms will be dissipating through the night, becoming a
more moderate rain and gusty wind threat into early Tuesday morning.
Southern IN counties and points southeast will be drying out early
in the morning on Tuesday with light winds veering according to the
location of the cold front. Tuesday morning lows remain warm in the
upper 50s to low 60s with clouds remaining thick overhead.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 415 AM EDT Mon Apr 27 2026

===Another Round of Storms Tuesday into Tuesday Night===

Tuesday morning through the afternoon, we will see a lull in precip
over the region. The cold front will stall over the Ohio River and
ample southwesterly flow will keep moisture over central Kentucky.
Looking to see dew points in the mid-upper 60s. Will see some sky
clearing, which will help temperatures warm into the upper 70s and
low 80s.

In the evening, a trough originating over Texas will move over the
Tennessee Valley and phase with the broader troughing over the
northern CONUS. A surface low pressure system, undergoing
cyclogenesis, is expected to move northeast over Kentucky in the
overnight hours. Ahead of this low pressure system, the shortwave
troughing will bring a source of lift to ample moisture over the
region. Storms will initially develop southwest over the mid-
Mississippi Valley and push northeast. These storms will be moving
into an environment that is favorable for convective activity: 2000-
3000J/kg of MLCAPE, 900 J/kg of DCAPE, 50kts of deep layer shear,
and good low and mid level lapse rates. A weak LLJ will result in
weak speed shear in the lowest levels, though good curvature is
still noted. The largest threats with this round of convection is
hail and wind. Currently, the SHIP (hail) parameter is showing
values approaching 1.0, therefore large hail will be possible.

Greatest threat area is along and south of the Western/Bluegrass
Parkway. Current onset timing is 7pm EDT and lasting through most
of the night, though weakening after midnight.

During the overnight hours, the environment will weaken as CAPE
decreases. Severe weather is expected to weaken through the night.
Though, as the low pressure system tracks over the region, showers
and storms are expected to continue through the night. Gusty to
damaging winds will be possible through Wednesday morning. The cold
front will begin to push southeast through the region on Wednesday
and push precip out slowly. CAA will lead to drier and cooler air on
Wednesday.

Additionally, rain tonight through Wednesday is 1.5-3.0 inches. With
larger totals over the western areas and tapering to the east. This
is much needed rainfall over the areas with the worst drought
currently. LPMMs show some swaths over our southwestern areas just
above 3 inches. With strong storms, brief and minor ponding will be
possible, but widespread flooding and flash flooding is not
expected.

Bust potential in this case is if we see delayed storms on Monday
night. This could delay the environment recovery on Tuesday and lead
to weaker convection. Though, forecast trends have shown bust
potential is quite low.

===Drier and Cooler Weather to End the Week===

Surface high pressure will build into the region on Thursday.
Conditions will remain cool and mostly dry through the weekend.
Zonal flow aloft will split the low Ohio Valley between a northern
trough and a southern stream system. Both systems may scrape by
bringing isolated to scattered chances to the far northern and far
southern areas of the region on Friday. Carrying low PoPs in the
forecast for Friday. High pressure will follow the Friday system and
keep conditions cool and dry.

Looking to see mild high temperatures in the mid 60s for Thursday
through the weekend. Low temperatures on Saturday and Sunday morning
will be chilly in the mid-upper 30s and touching 40. Some cooler
spots may see lows in the mid 30s, where we could see some frost
develop.

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 156 PM EDT Mon Apr 27 2026

A small line of TSRA will lift NE across southern IN at the start of
this TAF period, impacting HNB in the first hour of this TAF period.
HNB can expect MVFR and possibly brief IFR conditions in heavy TSRA.
Lightning, gusty winds, and small hail will all be possible at the
terminal.

Otherwise, mainly dry conditions will continue through the afternoon
hours in central KY. TSRA chances will mostly hold off until 00Z Tue
and beyond tonight. SCT TSRA chances will increase from the
northwest this evening ahead of a main convective line. This main
convective line will push southeast through southern IN and central
KY between 03-09Z Tue. Heavy rainfall, lightning, and strong gusty
winds will all be possible within this line. There is also a low-end
risk for a brief tornado. Low-end MVFR and borderline IFR ceilings
will develop in the wake of the storms early Tuesday. Low clouds
will slowly lift back to VFR Tue afternoon.

&&

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

&&

SHORT TERM...BKF
LONG TERM...SRW
AVIATION...EBW

Hazardous Weather Outlook
National Weather Service Louisville KY
402 AM EDT Mon Apr 27 2026

INZ076>079-083-084-089>092-KYZ023>043-045>049-053>057-061>067-
070>078-081-082-280815-
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-
402 AM EDT Mon Apr 27 2026 /302 AM CDT Mon Apr 27 2026/

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

.DAY ONE...Today and tonight.

There is a risk of severe storms tonight. Damaging winds and
isolated tornadoes are the main hazards.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Another round of strong to severe storms will be possible Tuesday
evening through early Wednesday morning.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures.

&&

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

Special Weather Statement
National Weather Service Louisville KY
157 PM EDT Mon Apr 27 2026

INZ083-089-271830-
Perry IN-Dubois IN-
157 PM EDT Mon Apr 27 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHERN DUBOIS AND NORTHWESTERN
PERRY COUNTIES THROUGH 230 PM EDT/130 PM CDT/...

At 156 PM EDT/1256 PM CDT/, Doppler radar was tracking a strong
thunderstorm near Folsomville, moving east at 45 mph.

HAZARD...Nickel size hail.

SOURCE...Radar indicated.

IMPACT...Minor hail damage to vegetation is possible.

Locations impacted include...
Huntingburg, Ferdinand, Holland, Saint Marks, Ranger, Sassafras,
Bristow, Bretzville, Adyeville, and Huntingburg Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

A Severe Thunderstorm Watch remains in effect until 700 PM EDT/600 PM
CDT/ for south central Indiana.

&&

LAT...LON 3835 8676 3810 8664 3807 8678 3808 8678
      3809 8677 3810 8677 3812 8681 3812 8680
      3815 8681 3816 8680 3818 8680 3818 8679
      3821 8679 3820 8707 3824 8707
TIME...MOT...LOC 1756Z 249DEG 40KT 3812 8709

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...<30 MPH

CSG