Alert archive / Iowa / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 523
The Storm Prediction Center issued this severe thunderstorm watch at Jul 25, 2012, 8:57 PM CDT for 8 counties in Illinois; 16 counties in Iowa. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 25, 2012, 8:57 PM CDT (01:57 UTC)
- Expired
- Jul 26, 2012, 3:00 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 24 counties
Benton County, IA, Buchanan County, IA, Cedar County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Washington County, IA, Carroll County, IL, Jo Daviess County, IL, Lee County, IL, Ogle County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL
The radar
The Quad Cities radar (KDVN), 56 km from the middle of the area, began a volume at 01:58 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
- 30%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 25, 9:22 PM CDT | Severe Thunderstorm Warning | DVN | Buchanan, Delaware, Linn | 53 min |
| Jul 25, 10:12 PM CDT | Severe Thunderstorm Warning | DVN | Delaware, Dubuque, Jackson, Jones, Linn | 63 min |
| Jul 25, 10:12 PM CDT | Severe Thunderstorm Warning | DVN | Buchanan | 48 min |
| Jul 25, 10:22 PM CDT | Severe Thunderstorm Warning | DVN | Benton, Buchanan, Iowa, Johnson, Linn | 53 min |
| Jul 25, 10:56 PM CDT | Severe Thunderstorm Warning | DVN | Cedar, Clinton, Jackson, Johnson, Jones, Linn | 64 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, 2.0 hours before the alert went out and 60 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
- 700 J/kg
- Mixed-layer CIN
- -149 J/kg
- Mixed-layer LCL
- 2702 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 84 m²/s²
- 0-3 km storm-relative helicity
- 158 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 25, 8:40 PM CDT | Mesoscale Discussion | SPC | Carroll, Henry, Jo Daviess, Mercer, Rock Island, Stephenson and 1 more | 65 min |
| Jul 25, 11:34 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, Henry, Jo Daviess and 7 more | 86 min |
| Jul 26, 1:40 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Cook, DeKalb, DuPage, Grundy and 15 more | 65 min |
| Jul 26, 12:09 PM CDT | Mesoscale Discussion | SPC | Boone, McHenry | 2 hr |
| Jul 26, 1:25 PM CDT | Mesoscale Discussion | SPC | Alexander, Bond, Clay, Clinton, Cumberland, Edwards and 27 more | 65 min |
| Jul 26, 1:46 PM CDT | Severe Thunderstorm Watch | SPC | Alexander, Clark, Clay, Clinton, Crawford, Cumberland and 28 more | 10 hr |
| Jul 26, 3:55 PM CDT | Mesoscale Discussion | SPC | Alexander, Clay, Clinton, Crawford, Edwards, Franklin and 24 more | 35 min |
| Jul 26, 6:29 PM CDT | Mesoscale Discussion | SPC | Alexander, Gallatin, Hamilton, Hardin, Johnson, Massac and 5 more | 61 min |
| Jul 25, 7:20 PM CDT | Mesoscale Discussion | SPC | Black Hawk, Boone, Bremer, Butler, Calhoun, Carroll and 25 more | 85 min |
| Jul 25, 7:21 PM CDT | Mesoscale Discussion | SPC | Cass, Fremont, Mills, Montgomery, Page, Pottawattamie and 1 more | 54 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.