Alert archive / Iowa / Tornado Watches in 2024

Tornado Watch 277

May 21, 20244 states

The Storm Prediction Center issued this tornado watch at May 21, 2024, 1:14 PM CDT for 4 states. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued: May 21, 2024, 1:14 PM CDT (18:14 UTC)
Expired: May 21, 2024, 9:00 PM CDT
In force: 8 hr
Issued by: the Storm Prediction Center
Particularly dangerous situation: Yes
Largest hail expected: 4 in
Strongest gust expected: 80 kt

All 118 counties

Adair County, IA, Adams County, IA, Allamakee County, IA, Appanoose County, IA, Audubon County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cedar County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clarke County, IA, Clayton County, IA, Clinton County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Emmet County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Henry County, IA, Howard County, IA, Humboldt County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Kossuth County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Mitchell County, IA, Monroe County, IA, Muscatine County, IA, Palo Alto County, IA, Pocahontas County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Sac County, IA, Scott County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Webster County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Wright County, IA, Carroll County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Mercer County, IL, Rock Island County, IL, Warren County, IL, Whiteside County, IL, Blue Earth County, MN, Carver County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Nicollet County, MN, Olmsted County, MN, Rice County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Watonwan County, MN, Winona County, MN, Buffalo County, WI, Crawford County, WI, Grant County, WI, La Crosse County, WI, Pepin County, WI, Richland County, WI, Trempealeau County, WI, Vernon County, WI

The radar

The Des Moines radar (KDMX), 71 km from the middle of the area, began a volume at 18:14 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: 90%
One or more EF2 to EF5 tornadoes: 80%
Ten or more severe wind reports: 80%
One or more gusts of 65 knots or more: 60%
Ten or more severe hail reports: 60%
One or more hailstones of 2 inches or more: 50%
Six or more combined severe hail and wind reports: 95%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 21, 1:38 PM CDT	Severe Thunderstorm Warning	DMX	Crawford	52 min
May 21, 2:18 PM CDT	Severe Thunderstorm Warning	DMX	Sac	29 min
May 21, 2:28 PM CDT	Severe Thunderstorm Warning	DMX	Adams, Audubon, Cass	62 min
May 21, 2:30 PM CDT	Severe Thunderstorm Warning	DMX	Audubon, Calhoun, Carroll, Crawford, Sac	45 min
May 21, 2:52 PM CDT	Tornado Warning	DMX	Adams, Cass	18 min
May 21, 2:52 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque, Jones	43 min
May 21, 2:55 PM CDT	Tornado Warning	DMX	Adair, Adams, Cass, Union	50 min
May 21, 2:57 PM CDT	Flash Flood Warning	DMX	Adair, Audubon, Carroll, Cass, Crawford, Greene and 1 more	6 hr
May 21, 3:07 PM CDT	Tornado Warning	DMX	Adair, Adams, Madison, Taylor, Union	53 min
May 21, 3:11 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Audubon, Boone, Calhoun, Carroll, Greene, Guthrie and 1 more	49 min
May 21, 3:13 PM CDT	Tornado Warning	DMX	Audubon, Cass, Greene, Guthrie	22 min
May 21, 3:26 PM CDT	Tornado Warning Tornado observed	DMX	Adair, Adams, Madison, Union	49 min
May 21, 3:28 PM CDT	Severe Thunderstorm Warning	DVN	Dubuque	33 min
May 21, 3:30 PM CDT	Severe Thunderstorm Warning	ARX	Grant	45 min
May 21, 3:31 PM CDT	Severe Thunderstorm Warning Destructive damage threat	DMX	Boone, Greene, Hamilton, Webster, Wright	44 min
May 21, 3:33 PM CDT	Tornado Warning	DMX	Ringgold, Taylor, Union	42 min
May 21, 3:35 PM CDT	Tornado Warning Tornado observedConsiderable damage threat	DMX	Adair, Dallas, Guthrie, Madison	40 min
May 21, 3:40 PM CDT	Tornado Warning Tornado observed	DMX	Adair, Adams, Dallas, Madison, Ringgold, Union	50 min
May 21, 3:55 PM CDT	Tornado Warning	DMX	Clarke, Madison, Ringgold, Union, Warren	50 min
May 21, 3:58 PM CDT	Tornado Warning	DMX	Clarke, Decatur, Lucas, Ringgold, Union, Warren	47 min
May 21, 3:59 PM CDT	Tornado Warning	MPX	Blue Earth, Faribault, Martin	46 min
May 21, 4:01 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Greene, Guthrie, Hamilton, Webster	44 min
May 21, 4:03 PM CDT	Tornado Warning	DMX	Boone, Hamilton, Webster	42 min
May 21, 4:11 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Clarke, Dallas, Decatur, Lucas, Madison and 4 more	64 min
May 21, 4:11 PM CDT	Severe Thunderstorm Warning	DMX	Hancock, Kossuth, Winnebago, Worth	49 min
May 21, 4:15 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Franklin, Hancock, Worth, Wright	45 min
May 21, 4:17 PM CDT	Severe Thunderstorm Warning	MPX	Faribault, Freeborn, Steele, Waseca	43 min
May 21, 4:19 PM CDT	Tornado Warning	DMX	Boone, Dallas, Polk, Story	41 min
May 21, 4:25 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Franklin, Grundy, Hamilton, Hardin, Marshall and 2 more	50 min
May 21, 4:26 PM CDT	Tornado Warning	MPX	Blue Earth	34 min
May 21, 4:30 PM CDT	Tornado Warning	DMX	Jasper, Madison, Polk, Warren	45 min
May 21, 4:31 PM CDT	Tornado Warning	MPX	Le Sueur, Waseca	33 min
May 21, 4:41 PM CDT	Flash Flood Warning	MPX	Blue Earth, Martin, Nicollet, Watonwan	3 hr
May 21, 4:43 PM CDT	Severe Thunderstorm Warning	DMX	Grundy, Hardin, Jasper, Marion, Marshall, Polk and 2 more	47 min
May 21, 4:46 PM CDT	Tornado Warning	DMX	Franklin, Grundy, Hamilton, Hardin	17 min
May 21, 4:46 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue	44 min
May 21, 4:48 PM CDT	Tornado Warning Tornado observedConsiderable damage threat	DMX	Hardin, Marshall, Polk, Story	31 min
May 21, 4:50 PM CDT	Severe Thunderstorm Warning	DMX	Butler, Cerro Gordo, Franklin, Grundy, Hardin	40 min
May 21, 4:50 PM CDT	Tornado Warning	MPX	Goodhue, Rice, Steele	40 min
May 21, 4:53 PM CDT	Tornado Warning	DMX	Appanoose, Lucas, Monroe, Wayne	52 min
May 21, 4:53 PM CDT	Severe Thunderstorm Warning	MPX	Freeborn, Steele	46 min
May 21, 5:03 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Floyd, Mitchell	57 min
May 21, 5:03 PM CDT	Tornado Warning	DMX	Jasper, Marshall	27 min
May 21, 5:08 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Dodge	52 min
May 21, 5:15 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Jasper, Marshall, Poweshiek, Tama	60 min
May 21, 5:17 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Lucas, Mahaska, Marion, Poweshiek, Warren	58 min
May 21, 5:17 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Bremer, Butler, Franklin, Grundy, Hardin and 1 more	58 min
May 21, 5:20 PM CDT	Tornado Warning	MPX	Dakota, Goodhue	22 min
May 21, 5:21 PM CDT	Severe Thunderstorm Warning	DVN	Van Buren	39 min
May 21, 5:24 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Chickasaw, Howard	66 min
May 21, 5:28 PM CDT	Tornado Warning	DMX	Mahaska, Marion, Monroe, Wapello	47 min
May 21, 5:29 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Grundy, Marshall, Tama	61 min
May 21, 5:41 PM CDT	Tornado Warning	DMX	Black Hawk, Tama	34 min
May 21, 5:41 PM CDT	Tornado Warning	DMX	Bremer, Butler, Grundy	22 min
May 21, 5:43 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Benton, Buchanan	47 min
May 21, 5:48 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Black Hawk, Bremer	42 min
May 21, 5:51 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Winneshiek	39 min
May 21, 5:54 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque, Jones	51 min
May 21, 5:54 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Henry, Jefferson, Van Buren, Washington	33 min
May 21, 5:58 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Poweshiek, Tama	47 min
May 21, 6:02 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Clinton, Jackson, Jones	43 min
May 21, 6:05 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Des Moines, Henry, Lee, Louisa, Van Buren	25 min
May 21, 6:05 PM CDT	Tornado Warning	ARX	Winona	25 min
May 21, 6:05 PM CDT	Severe Thunderstorm Warning	MPX	Dunn, Pepin, Pierce	55 min
May 21, 6:09 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Buffalo, Jackson, La Crosse, Monroe, Trempealeau	66 min
May 21, 6:14 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Fayette	46 min
May 21, 6:16 PM CDT	Tornado Warning	ARX	Wabasha, Winona	16 min
May 21, 6:17 PM CDT	Severe Thunderstorm Warning	DMX	Davis, Wapello	28 min
May 21, 6:18 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Benton, Iowa, Johnson, Keokuk	42 min
May 21, 6:24 PM CDT	Flash Flood Warning	ARX	Fayette, Winneshiek	3 hr
May 21, 6:24 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Benton, Buchanan, Delaware, Linn	51 min
May 21, 6:28 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Allamakee, Winneshiek	62 min
May 21, 6:29 PM CDT	Severe Thunderstorm Warning	DVN	Jo Daviess	31 min
May 21, 6:32 PM CDT	Tornado Warning	DVN	Benton, Buchanan	28 min
May 21, 6:35 PM CDT	Severe Thunderstorm Warning	ARX	Grant	25 min
May 21, 6:38 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Clinton, Johnson, Louisa, Muscatine, Scott	52 min
May 21, 6:40 PM CDT	Tornado Warning	ARX	Jackson, Trempealeau	31 min
May 21, 6:41 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Allamakee, Clayton, Winneshiek	52 min
May 21, 6:43 PM CDT	Severe Thunderstorm Warning	DVN	Van Buren	47 min
May 21, 6:47 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Jo Daviess	43 min
May 21, 6:47 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	La Crosse, Monroe, Vernon	43 min
May 21, 6:49 PM CDT	Flash Flood Warning	ARX	Allamakee, Winneshiek	3 hr
May 21, 6:49 PM CDT	Tornado Warning	ARX	Allamakee, Clayton, Fayette, Winneshiek	15 min
May 21, 6:52 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Benton, Buchanan, Delaware, Johnson, Jones, Linn	38 min
May 21, 6:55 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Carroll, Jo Daviess, Whiteside	50 min
May 21, 6:55 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Clark, Jackson, Monroe, Vernon	65 min
May 21, 7:00 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Carroll, Henry, Whiteside	45 min
May 21, 7:00 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Grant	14 min
May 21, 7:11 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Delaware, Dubuque, Jackson, Johnson, Jones and 1 more	49 min
May 21, 7:13 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Clinton, Muscatine, Scott	47 min
May 21, 7:23 PM CDT	Severe Thunderstorm Warning	DVN	Henry, Lee, Van Buren	24 min
May 21, 7:27 PM CDT	Severe Thunderstorm Warning Destructive damage threat	DVN	Carroll, Jo Daviess, Stephenson, Whiteside	48 min
May 21, 7:27 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Muscatine	18 min
May 21, 7:30 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Delaware, Dubuque, Jones, Linn	45 min
May 21, 7:38 PM CDT	Tornado Warning Tornado observedConsiderable damage threat	DVN	Cedar, Muscatine, Scott	22 min
May 21, 7:45 PM CDT	Severe Thunderstorm Warning	DVN	Bureau, Henry, Whiteside	28 min
May 21, 7:45 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Clayton	42 min
May 21, 7:51 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Jo Daviess	16 min
May 21, 7:55 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Cedar, Clinton, Jackson, Jones, Scott	50 min
May 21, 8:13 PM CDT	Severe Thunderstorm Warning Considerable damage threat	ARX	Grant, Richland	34 min
May 21, 8:31 PM CDT	Severe Thunderstorm Warning	DVN	Carroll, Jo Daviess, Stephenson	44 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, 6.2 hours before the alert went out and 243 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, 9:29 AM CDT	Mesoscale Discussion	SPC	Mercer, Rock Island	91 min
May 21, 12:32 PM CDT	Mesoscale Discussion	SPC	Mercer, Rock Island	118 min
May 21, 3:54 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Pike, Schuyler, Scott	2 hr
May 21, 5:33 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Pike	117 min
May 21, 5:56 PM CDT	Tornado Watch	SPC	Adams, Brown, Calhoun, Cass, Fulton, Greene and 9 more	6 hr
May 20, 9:23 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Calhoun, Cerro Gordo, Cherokee, Clay, Dickinson and 20 more	97 min
May 20, 10:01 PM CDT	Mesoscale Discussion	SPC	Audubon, Cass, Harrison, Mills, Montgomery, Pottawattamie and 1 more	119 min
May 20, 11:33 PM CDT	Severe Thunderstorm Watch	SPC	Fremont, Harrison, Mills, Monona, Montgomery, Page and 2 more	9 hr
May 20, 11:34 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Calhoun, Cerro Gordo, Cherokee, Chickasaw, Clay and 18 more	86 min
May 21, 2:04 AM CDT	Mesoscale Discussion	SPC	Crawford, Harrison, Mills, Monona, Pottawattamie, Shelby and 1 more	116 min
May 21, 5:51 AM CDT	Mesoscale Discussion	SPC	Adair, Adams, Appanoose, Audubon, Benton, Cass and 32 more	114 min
May 21, 6:15 AM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Appanoose, Audubon, Benton, Black Hawk and 45 more	7 hr
May 21, 10:27 AM CDT	Mesoscale Discussion	SPC	Cherokee, Crawford, Fremont, Harrison, Ida, Mills and 5 more	2 hr
May 21, 11:10 AM CDT	Tornado Watch	SPC	Buena Vista, Cherokee, Clay, Dickinson, Fremont, Harrison and 13 more	5 hr
May 21, 3:20 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Clarke, Dallas, Madison, Marion and 3 more	85 min
May 21, 5:03 PM CDT	Mesoscale Discussion	SPC	Appanoose, Benton, Black Hawk, Bremer, Buchanan, Butler and 29 more	87 min
May 21, 5:09 PM CDT	Mesoscale Discussion	SPC	Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 11 more	96 min
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, 6:18 PM CDT	Mesoscale Discussion	SPC	Adams, Barron, Calumet, Chippewa, Clark, Dunn and 18 more	87 min
May 21, 6:42 PM CDT	Tornado Watch	SPC	Adams, Brown, Calumet, Chippewa, Clark, Door and 20 more	5 hr

Nearby

Tornado Watches in Iowa, 2024 Tornado Watches in Minnesota, 2024 Tornado Watches in Illinois, 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.