Alert archive / Iowa / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 679
The Storm Prediction Center issued this severe thunderstorm watch at Jul 23, 2011, 5:16 PM CDT for 31 counties in Iowa; 12 counties in Missouri; 6 counties in Nebraska. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 23, 2011, 5:16 PM CDT (22:16 UTC)
- Expired
- Jul 23, 2011, 9:20 PM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 49 counties
Adair County, IA, Adams County, IA, Appanoose County, IA, Cass County, IA, Clarke County, IA, Davis County, IA, Decatur County, IA, Des Moines County, IA, Fremont County, IA, Henry County, IA, Jefferson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Mills County, IA, Monroe County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Andrew County, MO, Atchison County, MO, Clark County, MO, Gentry County, MO, Harrison County, MO, Holt County, MO, Mercer County, MO, Nodaway County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Worth County, MO, Cass County, NE, Johnson County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE
The radar
The Des Moines radar (KDMX), 78 km from the middle of the area, began a volume at 22:17 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
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 23, 5:24 PM CDT | Severe Thunderstorm Warning | OAX | Mills | 51 min |
| Jul 23, 5:43 PM CDT | Severe Thunderstorm Warning | DMX | Lucas, Monroe | 47 min |
| Jul 23, 6:15 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Lucas, Monroe, Wayne | 45 min |
| Jul 23, 6:34 PM CDT | Tornado Warning | DMX | Appanoose, Lucas, Monroe, Wayne | 26 min |
| Jul 23, 6:34 PM CDT | Severe Thunderstorm Warning | DVN | Des Moines, Lee | 45 min |
| Jul 23, 6:42 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Lucas, Monroe, Wayne | 48 min |
| Jul 23, 6:47 PM CDT | Tornado Warning | DMX | Appanoose, Wayne | 17 min |
| Jul 23, 7:05 PM CDT | Severe Thunderstorm Warning | EAX | Putnam | 40 min |
| Jul 23, 7:08 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Wayne | 52 min |
| Jul 23, 7:43 PM CDT | Severe Thunderstorm Warning | EAX | Putnam, Schuyler, Sullivan | 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
Omaha, NE (KOAX), launched 12:00Z, 10.3 hours before the alert went out and 199 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
- 1494 J/kg
- Mixed-layer CIN
- -247 J/kg
- Mixed-layer LCL
- 1815 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 135 m²/s²
- 0-3 km storm-relative helicity
- 65 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 |
|---|---|---|---|---|
| Jul 22, 7:38 PM CDT | Mesoscale Discussion | SPC | Benton, Black Hawk, Bremer, Buchanan, Butler, Cedar and 19 more | 97 min |
| Jul 23, 10:14 AM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Howard, Winneshiek | 4 hr |
| Jul 23, 1:10 PM CDT | Mesoscale Discussion | SPC | Allamakee, Winneshiek | 65 min |
| Jul 23, 1:52 PM CDT | Mesoscale Discussion | SPC | Clay, Dickinson, Emmet, Hancock, Kossuth, Lyon and 6 more | 83 min |
| Jul 23, 4:57 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Cass, Clarke, Dallas and 26 more | 93 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2011Severe Thunderstorm Watches in Missouri, 2011Severe Thunderstorm Watches in Nebraska, 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.