Hail and Damaging Winds in Indiana, April 13, 2026

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
255 PM CDT Mon Apr 13 2026

.KEY MESSAGES...

- Late spring to summer-like temperatures will continue through
  Friday with highs in the 70s and 80s and lows in the 60s.

- Several additional rounds of showers and thunderstorms,
  including a threat for severe weather and flooding expected,
  especially late Tuesday afternoon/evening and again on Wednesday.

- A brief break in the pattern is expected late Thursday into or
  through the day on Friday before another storm system arrives
  in the Friday evening to Saturday timeframe.

- In the wake of the Saturday cold front, a brief, potentially
  sharp, shot of much cooler air could bring frost/freeze
  concerns into next Sunday and Monday.

&&

.MESOSCALE...
Issued at 218 PM CDT Mon Apr 13 2026

Moisture advection along the northeastern terminus of an 850
low- level jet favored the early afternoon development of
scattered showers and storms across western IL. The expectation
is for this cluster of storms to continue sliding east-
northeastward across northern IL and into northwestern IN
through the afternoon. While the overall severe threat with the
storms this afternoon remains in question, the presence of steep
mid-level lapse rates and ample deep layer shear noted by long
straight hodographs suggest conditions will be favorable for
supercells capable of producing large hail through early this
evening. As of this writing, it appears the best environment
supportive of more substantial surface based storms resides
south of I-80. This is the area where more persistent insolation
through the day has pushed temperatures into the low 80s.
Accordingly, in collaboration with the SPC we have issued a
Severe Thunderstorm Watch for this area.

More substantial thunderstorms are slated to develop this
evening north-northwest of our area across portions of the Upper
Midwest in the vicinity of a surface warm front. With time,
conglomerate outflow from these storms will support upscale
growth into a east-southeastward shifting MCS late this evening
and overnight. We will be watching trends with this activity
closely through the evening, as it remains plausible that
northern parts of our area could get a glancing blow by these
storms overnight. Locally strong wind gusts, hail and heavy
rainfall would be the main threat with these storms overnight.

KJB

&&

.DISCUSSION...
Issued at 255 PM CDT Mon Apr 13 2026

Tuesday and Wednesday...

Tuesday and Wednesday, aggregate mid/upper level troughing
across the southwestern U.S. will slide eastward over the Four
Corners Region of the Desert Southwest. As this occurs, the
enhanced corridor of broad upper-level southwesterly flow from
the Plains to the Upper Midwest will be shunted farther eastward
into the Great Lakes. This will essentially steer a parade of
shortwave impulses northeastward across our area through
midweek. Altogether, this in addition to the favorable overlap
of the plume of steep mid-level lapse rates, stalled frontal
zone, a steady feed of low-level moisture advection and strong
deep-layer shear will support a threat for additional waves of
severe thunderstorms in the general region.

Of particular concern for more severe storms is the late
Tuesday afternoon and evening time period. Following any early
morning remnant storms, we should see primarily storm free
weather for much of the day as the area becomes capped under the
EML inversion. Accordingly, this should favor several hours of
diurnal heating and destabilization of the moist (dew points in
the 60s) low-level airmass through the day. Scattered thunderstorm
development then looks favorable in the vicinity of the frontal
boundary across eastern IA and southern WI sometime during the
mid to late afternoon hours of Tuesday. Given the favorable
thermodynamic and kinematic environment, supercells capable of
very large hail (2"+) will be a favorable, at least with the
initial activity. A notable tornado threat may also develop for
a few hours late in the afternoon through early evening across
eastern IA into northwestern IL. This as strengthening low-
level flow leads to enlarged low-level hodographs into early
evening. The storm mode does look to ultimately build upscale
into forward propagating segments through the evening, so a
transition to damaging wind producing storms is likely as the
storms progress east into northern IN later in the evening.

Hydrology will also become an increased concern Tuesday night,
particularly if repeated rounds of storms move over the same area.
If this occurs, a notable threat of flash flooding will
materialize into Tuesday night. Prior rounds of convection into
Wednesday morning may then muddle the picture convectively
speaking for Wednesday PM. Ultimately, pinpointing favored
locations and time windows will remain challenging until there is
better clarity on exact shortwaves and eventual placements of
boundaries.

KJB

Thursday through Sunday:

There's variance regarding the progression of a cold front
across the region, with some of the slower solutions holding
onto some potential for storms into Thursday afternoon.
Thereafter, into Thursday night and at least the start of
Friday, ensemble model guidance advertises a brief break in the
stormy pattern as shortwave ridging moves through the Great
Lakes ahead of a substantial trough digging into the central US.
High temperatures look to rebound into the low to even mid 80s
by Friday accompanied by another threat for strong to severe
thunderstorms Friday night into Saturday. Thereafter, there is a
reasonably strong signal in ensemble guidance for a cooldown to
start next week.

The key aspect for the weekend into early next week cooldown is
a recent trend towards a much cooler air mass due to trough
amplification over the region. If this comes to pass, parts of
the area may flirt with sub-freezing temperatures Saturday night
into early Sunday, and again Sunday night into next Monday
morning. With the summer-like warmth and rain this week
supercharging plant growth and leaf out, the magnitude of the
weekend cold shot will be one to watch for agricultural interests.

Castro/Borchardt

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1247 PM CDT Mon Apr 13 2026

Key Aviation Messages for the current TAF period:

- Multiple waves of showers and storms through the evening. Low
  confidence in coverage.

- Gusty southwest winds are expected through the TAF, with a
  chance of erratic gusty southeast winds for a brief period
  after 00Z

- Low level wind shear expected overnight as a low level jet
  increases

- Another chance for showers and storms closer to day break
  tomorrow.

Low level clouds have lifted to higher-end MVFR cigs for most of
the air space. While Chicago terminals are dry at the moment,
scattered showers with embedded thunder has crossed the
Mississippi River and is quickly moving northeast. Model
guidance has struggled with today's event, but surface and
radar observations helped justify converting PROB30s to TEMPOs
and help give a better estimate for showers and thunder at
terminals this afternoon. Winds will remain out of the southwest
with gusts 20 to 25 knots, though stronger gusts associated with
thunderstorms is possible.

While the current trends may be the main show, models (which
have already been mentioned as not handling the event well, thus
lower confidence in what they are projecting) continue to
highlight a second wave of showers and storms after 00Z. PROB30s
were maintained for northern terminals given the lower
confidence in coverage, but TEMPOs were added for MDW/GYY given
the trend in better coverage to the south. Additionally, there
could be a brief window of gusty southeast winds with this
second round of showers and storms tonight, before returning to
the southwest as the showers pass.

After 03Z, a low level jet is expected to increase with winds
exceeding 50 knots just 2000 ft AGL. The threat for low level
wind shear was maintained in the TAF. Most of the region should
remain dry overnight, however, the showers and thunderstorms
impacting Minnesota and Wisconsin during the day/evening today
is projected to move southeast over the airspace tonight. Many
models are suggesting most of the showers and storms will push
out over Lake Michigan. While there is lower confidence in this
final wave of precipitation, it merited a PROB30 inclusion in
the TAF.

Drier conditions are expected after daybreak tomorrow. MVFR cigs
hang on through the morning before eventually lifting to VFR
levels. Winds will remain out of the southwest with gusts 20 to
25 knots. There could we a weak wave in the afternoon that
provides isolated shower chances, but confidence was too low for
mention in the TAF presently.

DK

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

Visit us at weather.gov/chicago

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
1211 PM CDT Mon Apr 13 2026

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-141715-
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-
La Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford-
Northern Cook-Central Cook-Southern Cook-Northern Will-
Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-Benton-
1211 PM CDT Mon Apr 13 2026 /111 PM EDT Mon Apr 13 2026/

This Hazardous Weather Outlook is for portions of north central
Illinois...northeast Illinois and northwest Indiana.

.DAY ONE...This Afternoon and Tonight.

Weather hazards expected...

  Limited Thunderstorm Risk...with an associated:
     Level 2 of 5 Damaging Wind Risk...up to 60 mph.
     Level 2 of 5 Large Hail Risk...up to half dollar size.
  Limited Flooding Risk.

DISCUSSION...

Scattered thunderstorms are expected this afternoon into this
evening, a few severe of these storm may produce instances of large
hail and damaging winds. Locally heavy rainfall is also likely to
accompany these storms.

Additional weakening gusty thunderstorms may approach from the
northwest overnight tonight.

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

Tuesday and Wednesday...
  Elevated Thunderstorm Risk...with an associated:
     Level 3 of 5 Severe Thunderstorm Risk Tuesday.
     Level 2 of 5 Severe Thunderstorm Risk Wednesday.
     Limited Flooding Risk.

Thursday and Friday Night into Saturday...
 Limited Thunderstorm Risk.

DISCUSSION...

Waves of storms are expected Tuesday PM through Wednesday. Some
may be severe with all hazards including flash flooding.

.SPOTTER INFORMATION STATEMENT...

  Spotter reports may be needed this afternoon and evening.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the the east-northeast at around 45 mph.

LMZ740>745-141715-
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
1211 PM CDT Mon Apr 13 2026

This Hazardous Weather Outlook is for portions of the Illinois
nearshore waters of Lake Michigan and the Indiana nearshore
waters of Lake Michigan.

.DAY ONE...This Afternoon and Tonight.

Weather hazards expected...

  Hazardous conditions for small craft.
  Limited Thunderstorm Risk...with an associated:
     Level 2 of 5 Thunderstorm Wind Gust Risk...up to 50 kt.
     Level 2 of 5 Hail Risk...up to half dollar size.

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

Tuesday and Wednesday...
  Hazardous conditions for small craft are likely at times.
  Elevated Thunderstorm Risk...with an associated:
     Level 2 to 3 of 5 Severe Thunderstorm Risk.
Thursday through Saturday...
  Hazardous conditions for small craft are likely at times.
  Limited Thunderstorm Risk at times.
Sunday...
  Hazardous conditions for small craft are likely.

KJB

Visit us at www.weather.gov/chicago

Preliminary Local Storm Report
National Weather Service Chicago IL
156 PM CDT Mon Apr 13 2026

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

0155 PM     Hail             Marseilles              41.33N 88.71W
04/13/2026  E1.00 Inch       La Salle           IL   Trained Spotter

            Spotter reports lots of pea sized hail but a
            few stones up to quarter size.

&&

ZY

Preliminary Local Storm Report
National Weather Service Chicago IL
219 PM CDT Mon Apr 13 2026

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

0204 PM     Tstm Wnd Gst     2 S Bonfield            41.12N 88.05W
04/13/2026  M58 MPH          Kankakee           IL   Public

            Measured at PWS KILBONFI13.

&&

Preliminary Local Storm Report
National Weather Service Chicago IL
258 PM CDT Mon Apr 13 2026

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

0225 PM     Tstm Wnd Dmg     2 S Manteno             41.22N 87.83W
04/13/2026                   Kankakee           IL   Emergency Mngr

            Report of a tree down. Tree size unknown.
            Time estimated from radar.

&&

ZY

Preliminary Local Storm Report
National Weather Service Chicago IL
259 PM CDT Mon Apr 13 2026

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

0225 PM     Tstm Wnd Dmg     2 S Manteno             41.22N 87.83W
04/13/2026                   Kankakee           IL   Emergency Mngr

            Report of a tree down and 3 power poles
            snapped at the base. Tree size unknown. Time
            estimated from radar.

&&

ZY

Preliminary Local Storm Report
National Weather Service Chicago IL
301 PM CDT Mon Apr 13 2026

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

0221 PM     Tstm Wnd Dmg     1 N Chebanse            41.02N 87.91W
04/13/2026                   Kankakee           IL   Emergency Mngr

            Report of 2 power poles down. Relayed by EM.
            Time estimated via radar.

&&

ZY

Preliminary Local Storm Report
National Weather Service Chicago IL
307 PM CDT Mon Apr 13 2026

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

0300 PM     Tstm Wnd Gst     3 SE Crown Point        41.39N 87.33W
04/13/2026  E55 MPH          Lake               IN   Amateur Radio

            Estimate of 55 mph wind gust near Crown
            Point. Time estimated via radar.

&&

ZY