Alert archive / Iowa / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 437
The Storm Prediction Center issued this severe thunderstorm watch at Jun 29, 2012, 3:49 PM CDT for 8 counties in Illinois; 25 counties in Iowa. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 29, 2012, 3:49 PM CDT (20:49 UTC)
- Expired
- Jun 29, 2012, 9:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 33 counties
Benton County, IA, Cedar County, IA, Clinton County, IA, Des Moines County, IA, Henry County, IA, Iowa 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, 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, Bureau County, IL, Henderson County, IL, Henry County, IL, Mercer County, IL, Putnam County, IL, Rock Island County, IL, Warren County, IL, Whiteside County, IL
The radar
The Quad Cities radar (KDVN), 122 km from the middle of the area, began a volume at 20:51 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
9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 29, 4:09 PM CDT | Severe Thunderstorm Warning | DMX | Jasper | 66 min |
| Jun 29, 4:27 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Mahaska, Marion, Marshall, Poweshiek, Tama | 48 min |
| Jun 29, 4:33 PM CDT | Severe Thunderstorm Warning | DVN | Benton, Iowa, Johnson, Linn | 72 min |
| Jun 29, 5:24 PM CDT | Severe Thunderstorm Warning | DVN | Benton, Cedar, Iowa, Johnson, Jones, Linn | 66 min |
| Jun 29, 6:11 PM CDT | Severe Thunderstorm Warning | DVN | Clinton, Jackson | 64 min |
| Jun 29, 7:23 PM CDT | Severe Thunderstorm Warning | DVN | Whiteside | 47 min |
| Jun 29, 7:41 PM CDT | Severe Thunderstorm Warning | DVN | Bureau, Henry, Whiteside | 64 min |
| Jun 29, 8:19 PM CDT | Severe Thunderstorm Warning | DVN | Henderson, Mercer | 26 min |
| Jun 29, 8:22 PM CDT | Severe Thunderstorm Warning | DVN | Iowa, Johnson, Keokuk, Washington | 38 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, 8.8 hours before the alert went out and 129 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
- 2089 J/kg
- Mixed-layer CIN
- -252 J/kg
- Mixed-layer LCL
- 1383 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 93 m²/s²
- 0-3 km storm-relative helicity
- 150 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 5.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 29, 9:22 AM CDT | Mesoscale Discussion | SPC | Bureau, Champaign, DeWitt, Douglas, Edgar, Ford and 21 more | 2 hr |
| Jun 29, 10:49 AM CDT | Severe Thunderstorm Watch | SPC | Cook, DuPage, Grundy, Iroquois, Kane, Kankakee and 2 more | 6 hr |
| Jun 29, 7:59 AM CDT | Mesoscale Discussion | SPC | Lyon, Plymouth, Sioux | 91 min |
| Jun 29, 2:43 PM CDT | Mesoscale Discussion | SPC | Adair, Appanoose, Benton, Black Hawk, Boone, Buchanan and 31 more | 3 hr |
| Jun 29, 5:04 PM CDT | Mesoscale Discussion | SPC | Iowa, Johnson, Poweshiek | 26 min |
| Jun 29, 5:35 PM CDT | Mesoscale Discussion | SPC | Dickinson, Lyon, Osceola | 55 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2012Severe Thunderstorm Watches in Illinois, 2012Every severe thunderstorm watch in 2012
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.