Severe Thunderstorm Warning 337, NWS Indianapolis, IN

Area Forecast Discussion
National Weather Service Indianapolis IN
1253 AM EDT Thu Aug 20 2026

.KEY MESSAGES...

- Flood Watch in effect through 8AM Thursday across the northern
half of central IN with localized flash flooding possible

- Scattered to numerous showers and storms are expected this
afternoon into tonight, isolated severe storms are possible

- Generally drier late this week through early next week, but there
is a chance for showers and storms late Friday into Saturday

&&

.FORECAST UPDATE...
Issued at 1004 PM EDT Wed Aug 19 2026

Showers and thunderstorms continue across the northern half of
central Indiana this evening. Additional convection has developed in
central and northern Illinois, with isolated cells even developing
in northern Indiana.

These were forming in a moist atmosphere along a slow moving surface
front as well as numerous outflow boundaries across the region. Some
upper energy and mid level jet dynamics is also helping generate the
convection, especially over Illinois.

Convection across central Indiana will continue to slowly move
south. The slow movement will keep the threat for heavy rain and
flash flooding around. With the upper influence, the convection
across central Illinois should move southeast into the area into the
overnight (as the surface front slowly sinks south).

Some instability and shear exist, and KILX's radar has been showing
strong to near severe winds not far off the surface with the central
Illinois convection. Given these, isolated severe storms will remain
possible tonight. The best parameters may develop south of the
forecast area, per the latest Storm Prediction Center Mesoscale
Discussion.

Have slowed the progression of higher PoPs based on these trends.
Will likely have to make further adjustments depending as convection
evolves.

&&

.DISCUSSION (This evening through Wednesday)...
Issued at 332 PM EDT Wed Aug 19 2026

As of this afternoon, scattered thunderstorms have popped up across
north-central Indiana. There is a marginal severe threat this
afternoon through the evening with isolated damaging winds
possible and some hail as well. With how saturated the ground is,
trees could more easily be knocked over.

Flooding continues to be the main threat for the forecast area
unfortunately. Some of these afternoon storms are already
producing rain rate of over 2 in/hr, across northern portion of
the forecast area. A flood watch is in effect through the morning.
Rivers and creeks are likely to rise again from this rain. Where
exact impacts occur will depend on which river basin the highest
amounts of rainfall fall. Models have been largely highlighting
that some of these highest amounts will fall over the White River
basin, which could lead to river points along the White within
Indianapolis to return to action stage by the weekend and can't
rule out a chance of brief return to Minor flooding too.

Rivers remain high across the area, continue avoiding flood waters
and stay out of rivers.

Behind the wave, northwest flow will become more dominate aloft as
upper high pressure builds over the desert SW and upper troughing
builds to the NE of the forecast area. Meanwhile at the surface,
weak high pressure will generally be in the region leading to a
mostly dry rest of the forecast period outside of periodic chances
for showers and storms. Saturday seems to be the next best chance of
precipitation but again, those are still low chances. Temperatures
throughout the forecast period will see highs in the upper 70s to
low/mid 80s and lows from the upper 50s to mid 60s.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1252 AM EDT Thu Aug 20 2026

Impacts:

- Scattered SHRA/isolated TSRA ending north to south through 10Z.
- FG/low stratus likely overnight for most terminals.

Discussion:

Weak cold front located from near Terre Haute to north of Cincinnati
will continue to push south through 12Z. Near this boundary,
scattered SHRA will persist through 08Z to 10Z, with embedded TSRA
possible near KIND/KBMG/KHUF. Low stratus and/or BR/FG resulting in
MVFR to IFR conditions are likely after 08Z to 10Z, with CIGs below
500ft AGL possible, especially near areas that received the heaviest
rainfall Wednesday evening. Additional visibility reductions and
MVFR/IFR conditions are possible Thursday night. Winds behind the
front will remain northerly (010-040 degrees true) through the TAF
period, with speeds generally remaining 7 knots or less.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 8 AM EDT Thursday for INZ021-028>031-035>049-
054>057.

&&

UPDATE...50
AVIATION...BEP
DISCUSSION...KF

Hazardous Weather Outlook
National Weather Service Indianapolis IN
350 PM EDT Wed Aug 19 2026

INZ021-028>031-035>049-054>057-202000-
Carroll-Warren-Tippecanoe-Clinton-Howard-Fountain-Montgomery-Boone-
Tipton-Hamilton-Madison-Delaware-Randolph-Vermillion-Parke-Putnam-
Hendricks-Marion-Hancock-Henry-Morgan-Johnson-Shelby-Rush-
350 PM EDT Wed Aug 19 2026

This hazardous weather outlook is for central Indiana.

.DAY ONE...Through Tonight.

Widespread minor to moderate river flooding will continue along the
Wabash, White, and East Fork White Rivers and adjacent lowlands.

A flood watch is in effect through 8 AM Thursday as training
thunderstorms over saturated soils could lead to localized flash
flooding. Isolated strong to severe storms are also possible with
primarily a damaging wind gust threat and potential for some hail.

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

Thunderstorms will be possible on Saturday. Severe weather is not
expected, but lightning is a hazard with any storm.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report rainfall amounts or any severe
weather later today into tonight.

&&

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

INZ051>053-060>065-067>072-202000-
Vigo-Clay-Owen-Sullivan-Greene-Monroe-Brown-Bartholomew-Decatur-Knox-
Daviess-Martin-Lawrence-Jackson-Jennings-
350 PM EDT Wed Aug 19 2026

This hazardous weather outlook is for central Indiana.

.DAY ONE...Through Tonight.

Widespread minor to moderate river flooding will continue along the
Wabash, White, and East Fork White Rivers and adjacent lowlands.

Scattered thunderstorms are possible late today into tonight. Isolated
strong to severe storms are also possible with primarily a damaging
wind gust threat and potential for some hail.

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

Thunderstorms will be possible on Saturday. Severe weather is not
expected, but lightning is a hazard with any storm.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report rainfall amounts or any severe
weather later today into tonight.

&&

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

Preliminary Local Storm Report
National Weather Service Indianapolis IN
1005 PM EDT Wed Aug 19 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0936 PM     Flood            3 SE Anderson           40.06N 85.67W
08/19/2026                   Madison            IN   Public

            Lots of high water in southeast Anderson,
            Columbus Ave..53rd...60th Street areas
            across county along 53rd...300 S to Lapel.
            Ditches and streams have also risen
            considerably.

&&

BH

Preliminary Local Storm Report
National Weather Service Indianapolis IN
1015 PM EDT Wed Aug 19 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0815 PM     Flash Flood      Shadeland               40.37N 86.95W
08/19/2026                   Tippecanoe         IN   Public

&&

BH

Preliminary Local Storm Report
National Weather Service Indianapolis IN
1017 PM EDT Wed Aug 19 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0515 PM     Tstm Wnd Dmg     1 E Alexandria          40.26N 85.66W
08/19/2026                   Madison            IN   Public

            A tree was blown down.

&&

BH

Preliminary Local Storm Report
National Weather Service Indianapolis IN
1122 PM EDT Wed Aug 19 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0630 PM     Flash Flood      6 SE Rossville          40.37N 86.51W
08/19/2026                   Clinton            IN   911 Call Center

            Located in north center Clinton County. Time
            estimated from radar.

&&

BH

Preliminary Local Storm Report
National Weather Service Indianapolis IN
1124 PM EDT Wed Aug 19 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0730 PM     Flash Flood      2 W Michigantown        40.33N 86.43W
08/19/2026                   Clinton            IN   911 Call Center

            Flash flooding in northeast Clinton County.
            Time estimated from radar.

&&

BH

Special Weather Statement
National Weather Service Indianapolis IN
1246 AM EDT Thu Aug 20 2026

INZ036-043-044-051-052-200530-
Clay IN-Montgomery IN-Parke IN-Vermillion IN-Vigo IN-
1246 AM EDT Thu Aug 20 2026

...Strong thunderstorms will impact portions of Vigo, northwestern
Clay, Parke, Vermillion and southwestern Montgomery Counties through
130 AM EDT...

At 1245 AM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles west of Newport to 6 miles southwest of
Vermilion. Movement was east at 40 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Terre Haute, Brazil, Clinton, Rockville, Newport, West Terre Haute,
Fairview Park, Seelyville, Montezuma, Knightsville, Rosedale,
Harmony, Dana, Staunton, Waveland, Carbon, Universal, Mecca,
Bloomingdale, and Marshall.

This includes Interstate 70 between mile markers 1 and 25.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3991 8753 3991 8698 3987 8699 3987 8701
      3978 8701 3934 8711 3940 8753
TIME...MOT...LOC 0445Z 269DEG 36KT 3985 8752 3950 8765

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

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