Severe Thunderstorm Warning 178, NWS Northern Indiana

Area Forecast Discussion
National Weather Service Northern Indiana
834 PM EDT Thu Jun 11 2026

.KEY MESSAGES...

- Chances for severe weather exist again tonight. Damaging
  wind, hail, heavy rain, and a few tornadoes are possible with
  this severe weather threat.

- Next chances for showers and storms return Saturday night with
  another cool frontal passage, bringing cooler temperatures
  into low/mid 70s to lower 80s along with decreased humidity
  across the area Sunday and Monday.

- A moderate swim risk exists along the southeast Lake Michigan
  shoreline today and Friday as waves reach 2 to 4 feet.
  Breaking waves and currents are expected. Stay away from
  dangerous areas like piers, breakwalls, and river outlets.
  Always have a flotation device with you in the water.

&&

.UPDATE...
Issued at 833 PM EDT Thu Jun 11 2026

Tornado Watch 318 has been issued through 06z for most of the
area. A very unstable air mass continues to advect back
northeast over the area early this evening within a ramping low
level jet. Favorable low level hodo curvature enhanced by a
leftover boundary from earlier convection into areas west of
Interstate 69, and 40-50 kts of bulk shear in the 0-3 km layer
continue to make tornadoes a concern. Higher probabilities
remain for sig wind damage within any bowing segments.

Storm mode as of this writing is still a little messy just
upstream with attempts at a few supercells in the pre-frontal
environment now getting into far nw IN. These would carry a
tornado/hail/wind threat with an eventual merger into a QLCS
east through the area through the early overnight. Latest HRRR
and WoFS runs continue to suggest a weakening trend (becoming
more outflow dominant) as this activity gets into northwest OH,
though wind would still be a concern even if this occurs. A
local extension of the TOR Watch or a new Svr Watch may be
needed in our far eastern counties that were not included in
this watch.

&&

.DISCUSSION...
Issued at 349 PM EDT Thu Jun 11 2026

Severe weather is still looking likely tonight. The main line
of storms will be associated with a cold front currently
located over central WI/IA and northwest MO and orientated in a
northeast to southwest manner. This front will push continue to
push eastward this evening and the timing still is looking good
for this front to approach our western edge of the CWA around 9
PM EDT. Now there is a concern that some scattered storms may
pop-up ahead of this front that could impact our area earlier
due to an old linear MCS associated with an old outflow boundary
that has transited eastward across eastern IA/MO and through
central IL earlier today. Current radar shows that some of that
activity has made it to the eastern IL/western IN border. With
the very unstable airmass still present it would not take much
to get storms to develop from any outflows that push out from
these storms.

All of the ingredients for severe weather will be present
this evening with temperatures in the mid to upper 80s and dew
points in the upper 60s to low 70s in place across the CWA and
this will provide decent surface instability with about
2500-3500 J/kg of SB CAPE. The frontal boundary will also
provide a good lifting focal point (or even a stronger outflow
boundaries that may be present ahead of the front). Effective
bulk shear values of 35 to 55 kts are available with the higher
values located across our northwestern portions of the CWA.
300-400 m2/s2 of SR Helicity is also available ahead of the cold
front which will increase the tornado threat especially earlier
in the evening. SPC currently has a majority of our area under
an enhanced severe storm risk this evening.

The aforementioned storms that are just to the west of our area
could affect the environment and mitigate some of the potential
available for when the front does arrive. So will need to see
how that pans out and could be a fly in the ointment. There also
is the expectation that storms will weaken the further east they
move through the night so the better chances for severe storms
will be further west but cannot rule out a few storms remaining
strong well into the overnight period if the storms can manage
to remain balanced and not be overwhelmed by a descending cold
pool. The storms should be through the area by 3 to 4 AM EDT and
again all threats are on the table but the most likely threat
will be winds and a few tornadoes. Heavy rainfall will accompany
these storms but there will be good forward movement to help
keep the flooding risk at bay.

In the wake of the cold front we will have a cooler and drier
airmass move into the area and should provide a very nice couple
of mostly sunny spring days on Friday and Saturday with
temperatures in the mid 70s to mid 80s. The important part is
the humidity will be decreased with dew points dropping back
into the 50s.

The next chance of showers and storms will arrive late Saturday
and into Sunday morning with another cool frontal boundary
pushing through. SPC does currently have our area under a
marginal risk with that but the diurnal timing looks to perhaps limit
the potential of the storms and will need to monitor that once
we get through tonights event.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 641 PM EDT Thu Jun 11 2026

Main focus remains on timing of convective line expected to
track through KSBN mid-late evening and KFWA toward midnight.
Shear and instability profiles definitely hint at the risk for
strong to severe convection with a brief period of 50 kt plus
winds and LIFR/IFR conditions possible with the leading line.
VFR/dry then post-frontal into tomorrow otherwise with westerly
winds up around 12 knots.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 5 AM EDT Friday for LMZ043-046.

&&

UPDATE...Steinwedel
DISCUSSION...Andersen
AVIATION...Steinwedel

Preliminary Local Storm Report
National Weather Service Northern Indiana
1118 PM EDT Thu Jun 11 2026

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

1015 PM     Tstm Wnd Dmg     2 E Plymouth            41.35N 86.27W
06/11/2026                   Marshall           IN   Amateur Radio

            tree on powerlines.

&&

Preliminary Local Storm Report
National Weather Service Northern Indiana
1121 PM EDT Thu Jun 11 2026

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

1108 PM     Tstm Wnd Gst     2 ENE Nine Mile         40.98N 85.19W
06/11/2026  M70 MPH          Allen              IN   ASOS

&&

Preliminary Local Storm Report
National Weather Service Northern Indiana
1122 PM EDT Thu Jun 11 2026

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

1110 PM     Tstm Wnd Dmg     Sturgis                 41.80N 85.42W
06/11/2026                   St. Joseph         MI   911 Call Center

            trees and powerlines down.

&&

Preliminary Local Storm Report
National Weather Service Northern Indiana
1124 PM EDT Thu Jun 11 2026

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

1004 PM     Tstm Wnd Gst     Grissom Afb             40.65N 86.15W
06/11/2026  M64 MPH          Miami              IN   AWOS

&&

Preliminary Local Storm Report
National Weather Service Northern Indiana
1125 PM EDT Thu Jun 11 2026

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

1117 PM     Tstm Wnd Gst     1 NW Sturgis            41.81N 85.44W
06/11/2026  M58 MPH          St. Joseph         MI   AWOS

&&

Preliminary Local Storm Report
National Weather Service Northern Indiana
1128 PM EDT Thu Jun 11 2026

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

1120 PM     Non-Tstm Wnd Gst 4 WSW Woodburn          41.11N 84.92W
06/11/2026  E70 MPH          Allen              IN   Amateur Radio

&&