Alert archive / Illinois / Tornado Watches in 2023

Tornado Watch 96

March 31, 202318 counties in Illinois; 5 counties in Indiana; 12 counties in Wisconsin

The Storm Prediction Center issued this tornado watch at Mar 31, 2023, 2:36 PM CDT for 18 counties in Illinois; 5 counties in Indiana; 12 counties in Wisconsin. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Mar 31, 2023, 2:36 PM CDT (19:36 UTC)
Expired: Mar 31, 2023, 10:00 PM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 35 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, McHenry County, IL, Ogle County, IL, Will County, IL, Winnebago County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN, Dane County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Sauk County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Chicago radar (KLOT), 51 km from the middle of the area, began a volume at 19:38 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: 60%
One or more EF2 to EF5 tornadoes: 40%
Ten or more severe wind reports: 70%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 90%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Mar 31, 3:26 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	LaSalle, Livingston	34 min
Mar 31, 3:46 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Grundy, LaSalle, Livingston	44 min
Mar 31, 3:55 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, LaSalle, Lee	65 min
Mar 31, 4:07 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Will	38 min
Mar 31, 4:14 PM CDT	Severe Thunderstorm Warning	LOT	Kankakee	24 min
Mar 31, 4:26 PM CDT	Severe Thunderstorm Warning	LOT	Ogle	39 min
Mar 31, 4:33 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Will	57 min
Mar 31, 4:37 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kankakee, Will	38 min
Mar 31, 4:53 PM CDT	Severe Thunderstorm Warning	LOT	LaSalle, Lee	37 min
Mar 31, 6:06 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Kane	54 min
Mar 31, 6:08 PM CDT	Severe Thunderstorm Warning Considerable damage threat	MKX	Green, Iowa, Lafayette	67 min
Mar 31, 6:13 PM CDT	Flash Flood Warning	LOT	Cook, DuPage	58 min
Mar 31, 6:45 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Lee, Ogle, Winnebago	75 min
Mar 31, 6:54 PM CDT	Tornado Warning	LOT	Lee	36 min
Mar 31, 6:54 PM CDT	Severe Thunderstorm Warning	MKX	Dane, Green, Iowa	51 min
Mar 31, 6:56 PM CDT	Tornado Warning	LOT	Ogle	19 min
Mar 31, 7:08 PM CDT	Tornado Warning	MKX	Green, Rock	37 min
Mar 31, 7:09 PM CDT	Flash Flood Warning Considerable damage threat	LOT	Cook, DuPage, Lake	4 hr
Mar 31, 7:10 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	LaSalle	50 min
Mar 31, 7:11 PM CDT	Severe Thunderstorm Warning	MKX	Dane, Green, Iowa, Jefferson, Lafayette, Rock	64 min
Mar 31, 7:18 PM CDT	Tornado Warning	LOT	DeKalb, Lee, Ogle	42 min
Mar 31, 7:23 PM CDT	Tornado Warning	LOT	Boone, DeKalb, McHenry, Ogle, Winnebago	43 min
Mar 31, 7:26 PM CDT	Tornado Warning	MKX	Rock	49 min
Mar 31, 7:35 PM CDT	Severe Thunderstorm Warning Destructive damage threat	LOT	Kane, Kendall	40 min
Mar 31, 7:35 PM CDT	Tornado Warning	MKX	Dane, Jefferson, Rock	40 min
Mar 31, 7:38 PM CDT	Severe Thunderstorm Warning	LOT	Ford, Iroquois	22 min
Mar 31, 7:42 PM CDT	Tornado Warning	LOT	Ford, Iroquois	48 min
Mar 31, 7:43 PM CDT	Severe Thunderstorm Warning Destructive damage threat	LOT	Grundy, LaSalle	47 min
Mar 31, 7:49 PM CDT	Tornado Warning	MKX	Jefferson, Rock, Walworth	41 min
Mar 31, 7:50 PM CDT	Severe Thunderstorm Warning	MKX	Jefferson, Kenosha, Racine, Rock, Walworth, Waukesha	55 min
Mar 31, 7:52 PM CDT	Severe Thunderstorm Warning Destructive damage threat	LOT	Cook, DuPage, Lake, McHenry, Will	68 min
Mar 31, 8:15 PM CDT	Tornado Warning	LOT	Benton	32 min
Mar 31, 8:15 PM CDT	Tornado Warning Tornado observed	MKX	Jefferson	17 min
Mar 31, 8:16 PM CDT	Severe Thunderstorm Warning	LOT	Lake	14 min
Mar 31, 8:22 PM CDT	Severe Thunderstorm Warning	LOT	Lake, Porter	23 min
Mar 31, 8:23 PM CDT	Severe Thunderstorm Warning	MKX	Kenosha, Milwaukee, Racine	32 min
Mar 31, 8:34 PM CDT	Tornado Warning	LOT	Cook	11 min
Mar 31, 8:39 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Lake, Porter	46 min
Mar 31, 8:42 PM CDT	Tornado Warning	LOT	Jasper	25 min
Mar 31, 8:57 PM CDT	Tornado Warning	LOT	Lake, Porter	18 min
Mar 31, 9:07 PM CDT	Severe Thunderstorm Warning	LOT	Jasper, Lake, Newton, Porter	42 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

Davenport, (KDVN), launched 12:00Z, 7.6 hours before the alert went out and 207 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 897 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: 433 m²/s²
0-3 km storm-relative helicity: 424 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
Mar 31, 8:36 AM CDT	Mesoscale Discussion	SPC	Adams, Brown, Calhoun, Greene, Hancock, Jersey and 8 more	84 min
Mar 31, 10:37 AM CDT	Mesoscale Discussion	SPC	Adams, Brown, Cass, Fulton, Hancock, Henderson and 10 more	53 min
Mar 31, 11:24 AM CDT	Mesoscale Discussion	SPC	Adams, Brown, Bureau, Calhoun, Carroll, Cass and 27 more	96 min
Mar 31, 11:46 AM CDT	Tornado Watch PDS	SPC	Adams, Brown, Bureau, Calhoun, Carroll, Cass and 36 more	8 hr
Mar 31, 12:28 PM CDT	Tornado Watch PDS	SPC	Alexander, Bond, Clinton, Fayette, Franklin, Jackson and 14 more	11 hr
Mar 31, 12:53 PM CDT	Mesoscale Discussion	SPC	Alexander, Clinton, Franklin, Jackson, Jefferson, Johnson and 10 more	97 min
Mar 31, 1:32 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Fulton, Hancock, Knox, McDonough and 5 more	118 min
Mar 31, 2:07 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 26 more	83 min
Mar 31, 3:17 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Calhoun, Cass, Fulton, Greene and 20 more	88 min
Mar 31, 3:50 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 21 more	55 min
Mar 31, 5:18 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Bureau, Calhoun, Carroll, Cass and 27 more	117 min
Mar 31, 5:30 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Bureau, Calhoun, Carroll, Cass and 27 more	2 hr
Mar 31, 6:20 PM CDT	Mesoscale Discussion	SPC	Champaign, Clark, Coles, Cook, Crawford, Cumberland and 21 more	115 min
Mar 31, 6:59 PM CDT	Tornado Watch	SPC	Champaign, Christian, Clark, Clay, Coles, Crawford and 21 more	7 hr
Mar 30, 10:04 PM CDT	Mesoscale Discussion	SPC	Ashland, Bayfield, Douglas, Florence, Forest, Iron and 9 more	26 min
Mar 31, 3:38 PM CDT	Mesoscale Discussion	SPC	Adams, Columbia, Dodge, Juneau, La Crosse, Marquette and 2 more	2 hr

Nearby

Tornado Watches in Illinois, 2023 Tornado Watches in Wisconsin, 2023 Tornado Watches in Indiana, 2023 Every tornado watch in 2023

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.