Alert archive / Iowa / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 624
The Storm Prediction Center issued this severe thunderstorm watch at Jul 11, 2011, 3:30 AM CDT for 4 states. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 11, 2011, 3:30 AM CDT (08:30 UTC)
- Expired
- Jul 11, 2011, 9:46 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 70 kt
All 60 counties
Allamakee County, IA, Benton County, IA, Buchanan County, IA, Cedar County, IA, Chickasaw County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Howard County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Mitchell County, IA, Muscatine County, IA, Scott County, IA, Washington County, IA, Winneshiek County, IA, Bureau County, IL, Carroll County, IL, Henry County, IL, Jo Daviess County, IL, Mercer County, IL, Putnam County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Fillmore County, MN, Houston County, MN, Mower County, MN, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Grant 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, Richland County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI
The radar
The La Crosse radar (KARX), 114 km from the middle of the area, began a volume at 08:33 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
- 70%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
16 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 11, 4:10 AM CDT | Severe Thunderstorm Warning | MKX | Columbia, Dodge, Fond du Lac, Green Lake, Washington | 50 min |
| Jul 11, 4:20 AM CDT | Severe Thunderstorm Warning | DVN | Benton, Iowa, Johnson, Keokuk, Linn | 55 min |
| Jul 11, 4:49 AM CDT | Severe Thunderstorm Warning | DVN | Benton, Buchanan, Delaware, Linn | 56 min |
| Jul 11, 4:55 AM CDT | Severe Thunderstorm Warning | DVN | Benton, Cedar, Delaware, Iowa, Johnson, Jones and 1 more | 65 min |
| Jul 11, 5:13 AM CDT | Severe Thunderstorm Warning | MKX | Milwaukee, Ozaukee, Sheboygan, Washington, Waukesha | 24 min |
| Jul 11, 5:24 AM CDT | Severe Thunderstorm Warning | DVN | Buchanan, Delaware, Dubuque, Jackson, Jones, Linn | 66 min |
| Jul 11, 5:35 AM CDT | Severe Thunderstorm Warning | DVN | Carroll, Jo Daviess, Whiteside | 55 min |
| Jul 11, 5:38 AM CDT | Severe Thunderstorm Warning | ARX | Clayton | 58 min |
| Jul 11, 5:39 AM CDT | Severe Thunderstorm Warning | MKX | Lafayette | 51 min |
| Jul 11, 5:59 AM CDT | Severe Thunderstorm Warning | MKX | Iowa | 46 min |
| Jul 11, 6:11 AM CDT | Severe Thunderstorm Warning | DVN | Carroll, Jo Daviess, Rock Island, Stephenson, Whiteside | 64 min |
| Jul 11, 6:22 AM CDT | Severe Thunderstorm Warning | MKX | Green, Lafayette | 53 min |
| Jul 11, 6:42 AM CDT | Severe Thunderstorm Warning | MKX | Dane | 63 min |
| Jul 11, 6:49 AM CDT | Severe Thunderstorm Warning | MKX | Dane, Green, Jefferson, Rock, Walworth | 56 min |
| Jul 11, 7:36 AM CDT | Severe Thunderstorm Warning | MKX | Dane, Jefferson, Kenosha, Milwaukee, Racine, Walworth and 1 more | 54 min |
| Jul 11, 8:25 AM CDT | Severe Thunderstorm Warning | MKX | Milwaukee, Waukesha | 35 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 00:00Z, 8.5 hours before the alert went out and 138 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.
- Mixed-layer CAPE
- 3733 J/kg
- Mixed-layer CIN
- -2 J/kg
- Mixed-layer LCL
- 850 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 84 m²/s²
- 0-3 km storm-relative helicity
- 165 m²/s²
- Significant tornado parameter
- 3.4
- Supercell composite
- 14.3
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 11, 5:07 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 17 more | 113 min |
| Jul 11, 5:37 AM CDT | Severe Thunderstorm Watch | SPC | Boone, Cook, DeKalb, DuPage, Grundy, Kane and 9 more | 6 hr |
| Jul 11, 7:10 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Cass, Cook, DeKalb, DuPage and 27 more | 95 min |
| Jul 11, 7:50 AM CDT | Mesoscale Discussion | SPC | Champaign, Clark, Coles, Cook, DeWitt, Douglas and 14 more | 55 min |
| Jul 11, 5:16 PM CDT | Mesoscale Discussion | SPC | Cass, Champaign, DeWitt, Douglas, Ford, Fulton and 19 more | 59 min |
| Jul 10, 7:51 PM CDT | Mesoscale Discussion | SPC | Allamakee, Howard, Mitchell, Winneshiek | 84 min |
| Jul 10, 9:53 PM CDT | Mesoscale Discussion | SPC | Allamakee, Cerro Gordo, Chickasaw, Dickinson, Emmet, Floyd and 9 more | 67 min |
| Jul 10, 10:10 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Black Hawk, Bremer, Butler, Cerro Gordo, Chickasaw and 13 more | 6 hr |
| Jul 10, 10:27 PM CDT | Mesoscale Discussion | SPC | Cherokee, Harrison, Monona, Plymouth, Sioux, Woodbury | 63 min |
| Jul 10, 10:57 PM CDT | Severe Thunderstorm Watch | SPC | Harrison, Mills, Monona, Montgomery, Pottawattamie, Shelby | 4 hr |
| Jul 10, 11:45 PM CDT | Mesoscale Discussion | SPC | Allamakee, Bremer, Cerro Gordo, Chickasaw, Clayton, Delaware and 8 more | 90 min |
| Jul 10, 11:56 PM CDT | Severe Thunderstorm Watch | SPC | Buena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 5 more | 4 hr |
| Jul 11, 1:08 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Audubon, Black Hawk, Boone, Bremer and 38 more | 13 min |
| Jul 11, 1:21 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Audubon, Black Hawk, Boone, Bremer and 38 more | 4 hr |
| Jul 11, 2:36 AM CDT | Mesoscale Discussion | SPC | Adair, Adams, Benton, Black Hawk, Boone, Bremer and 52 more | 114 min |
| Jul 11, 2:07 AM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calumet, Clark, Columbia, Dodge and 27 more | 83 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2011Severe Thunderstorm Watches in Wisconsin, 2011Severe Thunderstorm Watches in Illinois, 2011Every severe thunderstorm watch in 2011
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.