Alert archive / Iowa / Severe Thunderstorm Watches in 2007
Severe Thunderstorm Watch 680
The Storm Prediction Center issued this severe thunderstorm watch at Sep 21, 2007, 3:53 PM CDT for 32 counties in Iowa; Houston County, Minnesota; 10 counties in Wisconsin. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 21, 2007, 3:53 PM CDT (20:53 UTC)
- Expired
- Sep 21, 2007, 7:43 PM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 43 counties
Adair County, IA, Allamakee County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Chickasaw County, IA, Clayton County, IA, Dallas County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Grundy County, IA, Hardin County, IA, Iowa County, IA, Jasper County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Polk County, IA, Poweshiek County, IA, Story County, IA, Tama County, IA, Warren County, IA, Winneshiek County, IA, Houston County, MN, Columbia County, WI, Crawford County, WI, Grant County, WI, Green Lake County, WI, Iowa County, WI, Lafayette County, WI, Marquette County, WI, Richland County, WI, Sauk County, WI, Vernon County, WI
The radar
The La Crosse radar (KARX), 125 km from the middle of the area, began a volume at 20:55 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
- 30%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 21, 3:57 PM CDT | Severe Thunderstorm Warning | ARX | Jackson, La Crosse, Monroe, Trempealeau, Vernon | 78 min |
| Sep 21, 4:59 PM CDT | Severe Thunderstorm Warning | ARX | Richland, Vernon | 46 min |
| Sep 21, 5:19 PM CDT | Severe Thunderstorm Warning | DMX | Marion, Warren | 26 min |
| Sep 21, 5:26 PM CDT | Severe Thunderstorm Warning | DMX | Black Hawk | 34 min |
| Sep 21, 5:26 PM CDT | Severe Thunderstorm Warning | DVN | Buchanan | 64 min |
| Sep 21, 5:31 PM CDT | Severe Thunderstorm Warning | ARX | Crawford | 29 min |
| Sep 21, 5:38 PM CDT | Severe Thunderstorm Warning | DVN | Benton | 67 min |
| Sep 21, 5:43 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Poweshiek, Tama | 47 min |
| Sep 21, 5:45 PM CDT | Severe Thunderstorm Warning | DMX | Mahaska, Marion | 45 min |
| Sep 21, 6:02 PM CDT | Severe Thunderstorm Warning | MKX | Sauk | 58 min |
| Sep 21, 6:10 PM CDT | Severe Thunderstorm Warning | DVN | Linn | 53 min |
| Sep 21, 6:13 PM CDT | Severe Thunderstorm Warning | ARX | Grant | 47 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, 8.9 hours before the alert went out and 163 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1379 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 37 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 20, 8:40 PM CDT | Mesoscale Discussion | SPC | Lyon | 95 min |
| Sep 21, 3:17 PM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 24 more | 88 min |
| Sep 21, 6:17 PM CDT | Mesoscale Discussion | SPC | Benton, Cedar, Clinton, Delaware, Des Moines, Dubuque and 16 more | 88 min |
| Sep 20, 11:13 PM CDT | Severe Thunderstorm Watch | SPC | Aitkin, Carlton, Cass, Cook, Crow Wing, Itasca and 4 more | 7 hr |
| Sep 21, 12:00 AM CDT | Tornado Watch | SPC | Becker, Beltrami, Benton, Big Stone, Chippewa, Clay and 28 more | 6 hr |
| Sep 21, 3:08 AM CDT | Mesoscale Discussion | SPC | Aitkin, Carlton, Cook, Itasca, Koochiching, Lake and 2 more | 2 hr |
| Sep 21, 3:29 AM CDT | Mesoscale Discussion | SPC | Becker, Beltrami, Benton, Big Stone, Chippewa, Clay and 27 more | 2 hr |
| Sep 21, 6:04 AM CDT | Severe Thunderstorm Watch | SPC | Aitkin, Anoka, Benton, Carlton, Carver, Cass and 24 more | 5 hr |
| Sep 21, 1:34 PM CDT | Mesoscale Discussion | SPC | Chisago, Cook, Dakota, Dodge, Fillmore, Freeborn and 10 more | 116 min |
| Sep 20, 11:09 PM CDT | Mesoscale Discussion | SPC | Barron, Burnett, Chippewa, Clark, Dunn, Eau Claire and 9 more | 81 min |
| Sep 21, 10:24 AM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calumet, Clark, Columbia, Dodge and 27 more | 66 min |
| Sep 21, 2:46 PM CDT | Tornado Watch | SPC | Adams, Ashland, Bayfield, Chippewa, Clark, Eau Claire and 25 more | 8 hr |
| Sep 21, 6:49 PM CDT | Mesoscale Discussion | SPC | Brown, Door, Kewaunee, Manitowoc, Sheboygan | 86 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2007Severe Thunderstorm Watches in Wisconsin, 2007Severe Thunderstorm Watches in Minnesota, 2007Every severe thunderstorm watch in 2007
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.