Alert archive / Wisconsin / Tornado Watches in 2024

Tornado Watch 281

May 21, 202426 counties in Wisconsin

The Storm Prediction Center issued this tornado watch at May 21, 2024, 6:42 PM CDT for 26 counties in Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: May 21, 2024, 6:42 PM CDT (23:42 UTC)
Expired: May 21, 2024, 11:48 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1 in
Strongest gust expected: 70 kt

All 26 counties

Adams County, WI, Brown County, WI, Calumet County, WI, Chippewa County, WI, Clark County, WI, Door County, WI, Eau Claire County, WI, Jackson County, WI, Juneau County, WI, Kewaunee County, WI, Langlade County, WI, Lincoln County, WI, Manitowoc County, WI, Marathon County, WI, Marinette County, WI, Menominee County, WI, Monroe County, WI, Oconto County, WI, Outagamie County, WI, Portage County, WI, Shawano County, WI, Taylor County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI

The radar

The Green Bay radar (KGRB), 51 km from the middle of the area, began a volume at 23:45 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: 80%
One or more gusts of 65 knots or more: 60%
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: 95%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 21, 6:47 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	La Crosse, Monroe, Vernon	43 min
May 21, 6:55 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Clark, Jackson, Monroe, Vernon	65 min
May 21, 7:03 PM CDT	Tornado Warning	MPX	Eau Claire	27 min
May 21, 7:07 PM CDT	Tornado Warning	ARX	Clark	38 min
May 21, 7:19 PM CDT	Severe Thunderstorm Warning Considerable damage threat	GRB	Marathon, Wood	26 min
May 21, 7:20 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Taylor	55 min
May 21, 7:29 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Adams, Juneau	61 min
May 21, 7:41 PM CDT	Severe Thunderstorm Warning Considerable damage threat	GRB	Marathon, Portage, Wood	49 min
May 21, 7:42 PM CDT	Tornado Warning	GRB	Marathon	33 min
May 21, 8:00 PM CDT	Tornado Warning	GRB	Langlade, Lincoln, Marathon	30 min
May 21, 8:03 PM CDT	Tornado Warning	GRB	Waushara	27 min
May 21, 8:18 PM CDT	Severe Thunderstorm Warning Considerable damage threat	GRB	Langlade, Marathon, Menominee, Outagamie, Portage, Shawano and 3 more	57 min
May 21, 8:24 PM CDT	Severe Thunderstorm Warning Considerable damage threat	GRB	Forest, Langlade, Lincoln, Oneida	51 min
May 21, 8:29 PM CDT	Tornado Warning	GRB	Forest, Langlade, Lincoln, Marathon, Menominee, Oconto and 2 more	46 min
May 21, 8:33 PM CDT	Tornado Warning	GRB	Winnebago	15 min
May 21, 8:41 PM CDT	Tornado Warning	GRB	Winnebago	9 min
May 21, 8:47 PM CDT	Severe Thunderstorm Warning Considerable damage threat	GRB	Brown, Calumet, Manitowoc, Outagamie, Waupaca, Winnebago	58 min
May 21, 9:07 PM CDT	Severe Thunderstorm Warning Considerable damage threat	GRB	Langlade, Marinette, Menominee, Oconto, Shawano	53 min
May 21, 9:21 PM CDT	Severe Thunderstorm Warning	GRB	Brown, Calumet, Door, Kewaunee, Manitowoc	39 min
May 21, 9:59 PM CDT	Severe Thunderstorm Warning	GRB	Door	46 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, 11.7 hours before the alert went out and 361 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: 1292 J/kg
Mixed-layer CIN: -75 J/kg
Mixed-layer LCL: 1074 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 63 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.4

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 21, 12:32 PM CDT	Mesoscale Discussion	SPC	Crawford, Grant, La Crosse, Vernon	118 min
May 21, 1:14 PM CDT	Tornado Watch PDS	SPC	Buffalo, Crawford, Grant, La Crosse, Pepin, Richland and 2 more	8 hr
May 21, 1:15 PM CDT	Mesoscale Discussion	SPC	Adams, Calumet, Columbia, Dane, Dodge, Fond du Lac and 9 more	90 min
May 21, 3:58 PM CDT	Tornado Watch	SPC	Columbia, Dane, Dodge, Fond du Lac, Green, Green Lake and 14 more	9 hr
May 21, 5:09 PM CDT	Mesoscale Discussion	SPC	Crawford	96 min
May 21, 6:18 PM CDT	Mesoscale Discussion	SPC	Adams, Barron, Calumet, Chippewa, Clark, Dunn and 18 more	87 min

Nearby

Tornado Watches in Wisconsin, 2024 Every tornado watch in 2024

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.