Alert archive / Wisconsin / Severe Thunderstorm Watches in 2025

Severe Thunderstorm Watch 596

August 16, 202512 counties in Illinois; Lake County, Porter County, Indiana; 20 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Aug 16, 2025, 1:56 PM CDT for 12 counties in Illinois; Lake County, Porter County, Indiana; 20 counties in Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Aug 16, 2025, 1:56 PM CDT (18:56 UTC)
Expired: Aug 16, 2025, 7:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 34 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Will County, IL, Winnebago County, IL, Lake County, IN, Porter County, IN, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Marquette County, WI, Milwaukee County, WI, Ozaukee County, WI, Racine County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 63 km from the middle of the area, began a volume at 19:00 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 10%
One or more EF2 to EF5 tornadoes: 2%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Aug 16, 1:59 PM CDT	Severe Thunderstorm Warning	MKX	Dane	16 min
Aug 16, 2:13 PM CDT	Severe Thunderstorm Warning	MKX	Rock, Walworth	47 min
Aug 16, 2:25 PM CDT	Severe Thunderstorm Warning	MKX	Green, Rock	50 min
Aug 16, 2:43 PM CDT	Severe Thunderstorm Warning	LOT	Boone, McHenry, Winnebago	47 min
Aug 16, 2:53 PM CDT	Severe Thunderstorm Warning	MKX	Rock, Walworth	52 min
Aug 16, 3:02 PM CDT	Severe Thunderstorm Warning	MKX	Rock	43 min
Aug 16, 3:04 PM CDT	Severe Thunderstorm Warning	LOT	Boone, Winnebago	40 min
Aug 16, 3:14 PM CDT	Severe Thunderstorm Warning	MKX	Columbia, Marquette, Sauk	46 min
Aug 16, 3:21 PM CDT	Severe Thunderstorm Warning	LOT	Lake, McHenry	54 min
Aug 16, 3:36 PM CDT	Severe Thunderstorm Warning	LOT	Boone, McHenry, Winnebago	39 min
Aug 16, 3:44 PM CDT	Severe Thunderstorm Warning	MKX	Columbia, Dodge, Fond du Lac, Green Lake	46 min
Aug 16, 3:48 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DeKalb, Kane, Lake, McHenry, Ogle	57 min
Aug 16, 4:03 PM CDT	Severe Thunderstorm Warning	MKX	Columbia, Dane, Dodge, Fond du Lac, Ozaukee, Sheboygan and 1 more	46 min
Aug 16, 4:10 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage	50 min
Aug 16, 4:21 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Kane	54 min
Aug 16, 4:25 PM CDT	Severe Thunderstorm Warning	MKX	Dane, Jefferson, Waukesha	35 min
Aug 16, 4:49 PM CDT	Severe Thunderstorm Warning	LOT	Lake	26 min
Aug 16, 5:00 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Kane, Kendall, Will	45 min
Aug 16, 5:11 PM CDT	Flash Flood Warning	LOT	DuPage	2 hr
Aug 16, 5:38 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Kankakee, Will	52 min
Aug 16, 6:45 PM CDT	Severe Thunderstorm Warning	LOT	Jasper, Lake, Newton, Porter	45 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 6.9 hours before the alert went out and 224 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 177 J/kg
Mixed-layer CIN: -223 J/kg
Mixed-layer LCL: 1561 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 49 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 16, 11:56 AM CDT	Mesoscale Discussion	SPC	Boone, Cook, DeKalb, DuPage, Kane, Lake and 2 more	2 hr
Aug 16, 2:34 PM CDT	Mesoscale Discussion	SPC	Boone, Cook, DeKalb, DuPage, Kane, Kendall and 5 more	86 min
Aug 16, 4:44 PM CDT	Mesoscale Discussion	SPC	Cook, DeKalb, DuPage, Grundy, Kane, Kankakee and 3 more	61 min
Aug 15, 7:24 PM CDT	Mesoscale Discussion	SPC	Buffalo, Chippewa, Clark, Dunn, Eau Claire, Jackson and 6 more	96 min
Aug 16, 7:20 AM CDT	Mesoscale Discussion	SPC	Barron, Buffalo, Burnett, Chippewa, Clark, Dunn and 12 more	85 min
Aug 16, 2:05 PM CDT	Mesoscale Discussion	SPC	Adams, Buffalo, Crawford, Jackson, Juneau, La Crosse and 7 more	85 min

Nearby

Severe Thunderstorm Watches in Wisconsin, 2025 Severe Thunderstorm Watches in Illinois, 2025 Severe Thunderstorm Watches in Indiana, 2025 Every severe thunderstorm watch in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.