Alert archive / Iowa / Severe Thunderstorm Watches in 2020

Severe Thunderstorm Watch 348

July 9, 20204 states

The Storm Prediction Center issued this severe thunderstorm watch at Jul 9, 2020, 11:05 AM CDT for 4 states. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued: Jul 9, 2020, 11:05 AM CDT (16:05 UTC)
Expired: Jul 9, 2020, 7:00 PM CDT
In force: 8 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 59 counties

Allamakee County, IA, Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clayton County, IA, Clinton County, IA, Davis County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Henry County, IA, Howard County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Mitchell County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Winneshiek County, IA, Worth County, IA, Henderson County, IL, Jo Daviess County, IL, Mercer County, IL, Rock Island County, IL, Warren County, IL, Fillmore County, MN, Freeborn County, MN, Houston County, MN, Mower County, MN, Crawford County, WI, Grant County, WI, Richland County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 156 km from the middle of the area, began a volume at 16:05 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: 20%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 50%
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: 10%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jul 9, 11:11 AM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Franklin, Worth	34 min
Jul 9, 11:42 AM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Hancock, Winnebago, Worth	63 min
Jul 9, 11:48 AM CDT	Severe Thunderstorm Warning	ARX	Floyd, Mitchell	72 min
Jul 9, 12:30 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Bremer, Butler, Grundy	45 min
Jul 9, 12:58 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Bremer	62 min
Jul 9, 12:59 PM CDT	Severe Thunderstorm Warning	DVN	Jo Daviess	31 min
Jul 9, 1:11 PM CDT	Severe Thunderstorm Warning	DVN	Buchanan	34 min
Jul 9, 1:18 PM CDT	Severe Thunderstorm Warning	ARX	Chickasaw, Fayette	87 min
Jul 9, 1:22 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Bremer	38 min
Jul 9, 1:44 PM CDT	Severe Thunderstorm Warning	ARX	Winneshiek	61 min
Jul 9, 2:15 PM CDT	Flash Flood Warning	DMX	Black Hawk	2 hr
Jul 9, 2:19 PM CDT	Severe Thunderstorm Warning	DVN	Benton	26 min
Jul 9, 2:29 PM CDT	Severe Thunderstorm Warning	ARX	Allamakee, Clayton	61 min
Jul 9, 2:30 PM CDT	Severe Thunderstorm Warning	DVN	Buchanan	30 min
Jul 9, 2:56 PM CDT	Severe Thunderstorm Warning	DVN	Delaware	34 min
Jul 9, 2:57 PM CDT	Severe Thunderstorm Warning	ARX	Houston	40 min
Jul 9, 3:29 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque, Jones, Linn	31 min
Jul 9, 3:56 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Johnson, Jones, Linn	34 min
Jul 9, 4:16 PM CDT	Flash Flood Warning	DVN	Jo Daviess	3 hr
Jul 9, 4:22 PM CDT	Severe Thunderstorm Warning	DVN	Jo Daviess	23 min
Jul 9, 4:24 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Jones	36 min
Jul 9, 5:03 PM CDT	Flash Flood Warning Considerable damage threat	DVN	Jo Daviess	2 hr
Jul 9, 5:08 PM CDT	Severe Thunderstorm Warning	DVN	Mercer, Rock Island	52 min
Jul 9, 5:19 PM CDT	Tornado Warning	DVN	Cedar, Muscatine	14 min
Jul 9, 5:35 PM CDT	Severe Thunderstorm Warning	DVN	Mercer, Rock Island	40 min
Jul 9, 6:06 PM CDT	Severe Thunderstorm Warning	DVN	Henderson, Mercer, Warren	39 min
Jul 9, 6:09 PM CDT	Severe Thunderstorm Warning	DVN	Henry, Mercer, Rock Island, Whiteside	51 min
Jul 9, 6:22 PM CDT	Tornado Warning	DVN	Henderson, Warren	38 min

Discussions around it

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

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 9, 10:24 AM CDT	Mesoscale Discussion	SPC	Mercer, Rock Island	3 hr
Jul 9, 2:51 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 22 more	114 min
Jul 9, 3:39 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Bureau, Carroll, Henry, Knox, Lee and 9 more	7 hr
Jul 9, 5:39 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, DeKalb, DuPage, Grundy and 19 more	96 min
Jul 8, 8:39 PM CDT	Mesoscale Discussion	SPC	Harrison, Monona, Plymouth, Woodbury	96 min
Jul 8, 7:58 PM CDT	Mesoscale Discussion	SPC	Aitkin, Benton, Big Stone, Carlton, Cass, Crow Wing and 16 more	2 hr
Jul 8, 9:51 PM CDT	Mesoscale Discussion	SPC	Aitkin, Anoka, Benton, Big Stone, Carlton, Cass and 24 more	114 min
Jul 9, 12:53 AM CDT	Mesoscale Discussion	SPC	Aitkin, Carlton, Cass, Crow Wing, Douglas, Grant and 11 more	3 hr

Nearby

Severe Thunderstorm Watches in Iowa, 2020 Severe Thunderstorm Watches in Illinois, 2020 Severe Thunderstorm Watches in Minnesota, 2020 Every severe thunderstorm watch in 2020

Sources

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