Alert archive / Iowa / Severe Thunderstorm Watches in 2009
Severe Thunderstorm Watch 270
The Storm Prediction Center issued this severe thunderstorm watch at May 8, 2009, 1:21 PM CDT for 50 counties in Iowa. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- May 8, 2009, 1:21 PM CDT (18:21 UTC)
- Expired
- May 8, 2009, 7:28 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 50 counties
Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Franklin County, IA, Fremont County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Humboldt County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Mills County, IA, Monroe County, IA, Montgomery County, IA, Page County, IA, Pocahontas County, IA, Polk County, IA, Pottawattamie County, IA, Poweshiek County, IA, Ringgold County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Webster County, IA, Wright County, IA
The radar
The Des Moines radar (KDMX), 43 km from the middle of the area, began a volume at 18:22 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
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 8, 5:15 PM CDT | Severe Thunderstorm Warning | DMX | Marshall, Tama | 45 min |
| May 8, 5:27 PM CDT | Severe Thunderstorm Warning | DMX | Marshall, Poweshiek, Tama | 32 min |
| May 8, 6:26 PM CDT | Severe Thunderstorm Warning | DMX | Monroe | 22 min |
| May 8, 6:46 PM CDT | Severe Thunderstorm Warning | DMX | Wapello | 29 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 |
|---|---|---|---|---|
| May 8, 1:05 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Benton, Black Hawk and 54 more | 85 min |
| May 8, 5:47 PM CDT | Mesoscale Discussion | SPC | Appanoose, Benton, Black Hawk, Buchanan, Cedar, Clayton and 29 more | 58 min |
| May 8, 6:10 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Cedar, Clayton, Clinton, Delaware, Des Moines and 15 more | 4 hr |
Nearby
Severe Thunderstorm Watches in Iowa, 2009Every severe thunderstorm watch in 2009
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.