Tornadoes and Flash Flood in Indiana, June 18, 2026

Area Forecast Discussion
National Weather Service Louisville KY
133 AM EDT Thu Jun 18 2026

.KEY MESSAGES...

* Storms are ongoing across south central IN and southern IL
  that will continue to move east into the forecast area. All
  severe threats remain on the table as these storms have a
  history of producing.

* A Flood Watch is in effect from 9 PM EDT tonight to 9 AM EDT
  tomorrow, mainly along and north of I-64.

* The cold front stalls across the region, leading to additional
  potential for scattered strong to severe storms, excessive
  rainfall, and isolated flash flooding across south-central KY
  Thursday afternoon and evening.

* A reprieve from rainfall comes Friday and Saturday before the next
  round of widespread rain returns starting late Saturday night.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 133 AM EDT Thu Jun 18 2026

A low pressure system is currently centered over the Wisconsin and
Illinois border with a cold front stretched SW through northern
Illinois and north central Missouri. A low level jet is also
centered over central Indiana that will begin to sink south slightly
as the cold front starts to push SE.

Ahead of the front, a line of strong to severe storms will move
through the Ohio Valley overnight. Southern IN counties can expect
storms to start to move in between 12 and 2 am EDT, and continue to
move SE into northern KY through the early morning hours. Storms
will have the potential to produce wind, hail, and even a few
tornadoes. The greatest severe potential remains in southern IN and
northern KY along the Ohio River. The environment is expected to
hold on to 1500 - 2000 J/kg with the capping expected to diminish
through the night. Additionally, low level wind shear values will
likely range from 40-50 kts as a strong low level jet is over the
area through the night. There is a possibility that the lower level
inhibition holds on and decreases the severe threat to the area by
preventing any additional growth. PWAT values are currently hovering
around 2" and are expected to hold steady. As storms move through
this leads to a flash flooding concern, especially with training
storms. QPF values will likely range 1" to 2" throughout the area,
with some localized values of 3" possible with longer residence
times. A Flood Watch is has been issued for the northern part of the
CWA through Thursday morning.

Thursday afternoon and evening another round of severe storms are
possible for central and southern parts of KY as the cold front
slows over the Ohio Valley. As ample moisture stays in place over
the region flooding will be an area of concern, along with damaging
winds. A secondary Flood Watch for tomorrow is likely for areas in
south central KY. The overall shear profile will weaken through the
day tomorrow, deceasing the threat for tornado potential. Scattered
rain showers and a few thunderstorms will move in behind this line
of storms that will persist overnight.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 133 AM EDT Thu Jun 18 2026

The previously mentioned cold front will finally move out of eastern
KY Friday morning, along with any lingering rain showers. Surface
high pressure will build in behind the front bringing warm and dry
weather. Northwesterly flow will become dominant keeping maximum
temperatures on Friday in the low 80s with mostly clear skies.
Dewpoints are expected to stay in the upper 50s and low 60s, leading
to a very nice Friday. Saturday is looking to be a rinse and repeat
with highs in the low to mid 80s.

Dry weather comes to an end for the later half of the weekend as a
shortwave ejects from the Rockies Saturday night into Sunday morning.
A surface low pressure will then form and move into the Ohio Valley.
Widespread rain showers and scattered thunderstorms are expected to
move ESE through the forecast area Sunday afternoon and evening into
Monday. Severe threats are uncertain at this point, but is not out
of the question. Instability seems to be marginal with the highest
values remaining elevated. PWAT values greater than 1.5" will
quickly build into the area ahead of the low. Long range guidance is
estimating QPF near 1.5" by Monday night, therefore continued
monitoring will be needed for any flooding concerns.

The surface low will move east out of the area Monday evening, with
another area of high pressure building in behind it. Several chances
for scattered rain showers through midweek will be possible as
several shortwaves move through. However, chances remain low as the
high pressure and drier air stays in place. Temperatures are
expected to remain in the low to mid 80s through midweek.

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 127 AM EDT Thu Jun 18 2026

Gusty southwesterly winds will prevail through the overnight period.
A line of showers and storms will drop south through the overnight
hours. Some storms will be strong to severe bringing a chance for
severe weather hazards and heavy rainfall. This line of showers and
storms will weaken as it moves south. VIS will likely drop to 1-2SM
at times. South of I64, CIGs are expected to be high-end MVFR in the
morning and into the early afternoon and showers and storms
continue.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Flood Watch until 9 AM EDT this morning for KYZ025-029>043-049.
IN...Flood Watch until 9 AM EDT /8 AM CDT/ this morning for
     INZ076>079-083-084-089>092.

&&

SHORT TERM...CAL
LONG TERM...CAL
AVIATION...SRW