Severe Thunderstorm Warning 276, NWS Northern Indiana

Area Forecast Discussion
National Weather Service Northern Indiana
1215 PM EDT Tue Aug 11 2026

.KEY MESSAGES...

- Strong to severe storms, accompanied by damaging winds, looks
  to continue and spread further into the rest of the area by
  early afternoon into this evening. All threats are possible
  however the main threats will be wind and hail as well as
  heavy rainfall.

- The potential for flooding will increase into this afternoon
  due to both recent heavy rainfall and additional heavy
  rainfall through this evening. A Flood Watch is currently in
  effect for most of the area.

- Rain chances may linger through the week, especially south of US-
  30.

&&

.DISCUSSION...
Issued at 1122 AM EDT Tue Aug 11 2026

Will focus on the near term for this discussion with a rather
busy morning with the continuation of convective activity along
a boundary draped from the west out over northern IL and then
in a southeasterly orientation into our southern portions of the
CWA. The activity has currently been developing along this
boundary and training over the same areas which has increased
the threat of flash flooding and areal flooding in those areas.
This will only be exasperated further with the expectation of
the storms continuing across that area into the this evening
with periods of heavy rainfall to continue. A Flash Flood Watch
is in effect until 8 PM EDT for all of the Indiana and Ohio
counties in our CWA. Also, with a large convective bow structure
sitting northern IL and pushing eastward into the area this
will help push convection further north and southward from the
boundary expanding the areal coverage to the rest of the CWA
into this late afternoon and early evening.
Showers/thunderstorms may continue beyond that especially the
southerly half of the CWA into the overnight hours.

With the very moist airmass in place and plenty of instability
ranging from around 1500 J/kg to the eastern portions of the
area to around 4500 J/kg for our west and southwest portions of
the area. Bulk shear values of 40 to 50 kts with even a few
pockets around 60 kts pushing into the area from the west with
the MCS disturbance currently over northern IL. The increased
shear looks to keep the things more organized and will be
interesting to see how this evolves as it pushes through the
area. All threats are on the table but damaging winds and the
heavy rainfall seems to be the main expected threats at this
time, but with marginal SR Helicity values around 100 m2/s2
tornadic spin-ups would be possible especially along the main
bowing structure and potential bookend vorticies. The Helicity
values do look to peak later this afternoon in the rear of this
bowing structure so will need to watch out for storms that may
develop in it's wake later today for the potential for spin-ups.
SPC does currently have a majority of our CWA, especially the
southwestern half under an enhanced risk for severe storms
today and a severe thunderstorm watch has been issued for the
entire CWA until 5 PM EDT this evening.

The main boundary pushes southward tonight and will see the
shower/thunderstorm activity do the same with the better chances
for mainly our southern portions of the CWA (mainly south of
US-30 and most likely south of US-24). SPC does have a marginal
risk for severe storms for our far southern portions of the CWA.

With this stagnant ring of fire/zonal flow pattern to continue
through the end of the week and into the weekend periods of
showers/storms will be possible each day across the area with
afternoons and evening periods with the greater chances.
Seasonable temperatures will also remain the theme. However, will
be watching for ridging from the south to push northward which
will make for warmer temperatures and more humid conditions but
still a decent amount of uncertainty on the longer range
forecast.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 625 AM EDT Tue Aug 11 2026

Generally VFR conditions expected outside of periods of convection
through today. There may be some brief MVFR cigs through 15Z, but
expect cloud bases to generally be above 025 afterwards. For the
next few hours, convection will be primarily focused towards FWA
with lower chances at SBN, but as additional thunderstorms develop
towards the afternoon, periods of MVFR to IFR vsbys are likely along
with outflow driven gusts of 30-40kts. Outside of convection, there
may be a few southwesterly wind gusts up to 20kts but these gusts
should remain infrequent. Chances for convection look to lower after
00Z with the development of fog/low stratus likely after 06Z through
the end of the TAF period.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch until 8 PM EDT /7 PM CDT/ this evening for
     INZ005>009-012>015-017-018-020-022>027-032>034-103-104-
     116-203-204-216.
OH...Flood Watch until 8 PM EDT this evening for OHZ001-002-004-005-
     015-016-024-025.
MI...None.
MARINE...None.

&&

DISCUSSION...Andersen
AVIATION...Fisher

Preliminary Local Storm Report
National Weather Service Northern Indiana
1135 AM EDT Tue Aug 11 2026

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

1035 AM     Hail             Knox                    41.29N 86.62W
08/11/2026  M2.00 Inch       Starke             IN   Public

            Photo of 2 inches hailstones in Knox.
            Measured with a ruler. Time estimated via
            radar.

&&

MJ

Preliminary Local Storm Report
National Weather Service Northern Indiana
1136 AM EDT Tue Aug 11 2026

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

1035 AM     Hail             Knox                    41.29N 86.62W
08/11/2026  E2.50 Inch       Starke             IN   Public

            Photo of what appears to be hen egg to
            tennis ball sized hail in Knox (2 to 2.5
            inches in diameter). Time estimated via
            radar.

&&

MJ

Preliminary Local Storm Report
National Weather Service Northern Indiana
1200 PM EDT Tue Aug 11 2026

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

1030 AM     Hail             Toto                    41.26N 86.70W
08/11/2026  E2.00 Inch       Starke             IN   Public

            Photo on Facebook of a 2 inch hailstone in
            Toto that fell at 930 AM CDT.

&&

MJ

Preliminary Local Storm Report
National Weather Service Northern Indiana
1211 PM EDT Tue Aug 11 2026

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

1030 AM     Hail             3 E English Lake        41.26N 86.78W
08/11/2026  M2.75 Inch       Starke             IN   Public

            Hail damage to cars on Toto Road north of
            north Judson from baseball sized hail.

&&

MJ

Preliminary Local Storm Report
National Weather Service Northern Indiana
1219 PM EDT Tue Aug 11 2026

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

1110 AM     Hail             1 N North Judson        41.23N 86.78W
08/11/2026  M2.75 Inch       Starke             IN   Public

            Damage to car windshields and roofs in North
            Judson due to large hail.

&&

MJ

Preliminary Local Storm Report
National Weather Service Northern Indiana
1222 PM EDT Tue Aug 11 2026

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

1110 AM     Hail             2 W Toto                41.26N 86.74W
08/11/2026  E3.00 Inch       Starke             IN   Public

            Estimated 3 inch hailstone. Photo on
            Facebook but no official measurement. Fell
            on SR 39 north of North Judson. Time
            estimated via radar.

&&

MJ