Alert archive / Iowa / Severe Thunderstorm Watches in 2007
Severe Thunderstorm Watch 526
The Storm Prediction Center issued this severe thunderstorm watch at Jul 17, 2007, 4:37 AM CDT for 4 counties in Illinois; 16 counties in Iowa. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 17, 2007, 4:37 AM CDT (09:37 UTC)
- Expired
- Jul 17, 2007, 8:00 AM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 70 kt
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, Henry County, IL, Mercer County, IL, Rock Island County, IL, Whiteside County, IL
The radar
The Quad Cities radar (KDVN), 71 km from the middle of the area, began a volume at 09:39 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
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 70%
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 |
|---|---|---|---|---|
| Jul 17, 4:54 AM CDT | Severe Thunderstorm Warning | DVN | Jones | 51 min |
| Jul 17, 5:34 AM CDT | Flash Flood Warning | DVN | Linn | 6 hr |
| Jul 17, 7:14 AM CDT | Flash Flood Warning | DVN | Buchanan | 6 hr |
| Jul 17, 7:20 AM CDT | Flash Flood Warning | DVN | Johnson | 6 hr |
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, 9.6 hours before the alert went out and 78 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
- 405 J/kg
- Mixed-layer CIN
- -77 J/kg
- Mixed-layer LCL
- 1277 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 211 m²/s²
- 0-3 km storm-relative helicity
- 243 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.4
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 16, 9:50 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DuPage, Grundy and 21 more | 85 min |
| Jul 17, 2:53 AM CDT | Mesoscale Discussion | SPC | Rock Island | 82 min |
| Jul 17, 6:58 AM CDT | Mesoscale Discussion | SPC | Bureau, Cass, DeWitt, Fulton, Grundy, Henderson and 17 more | 92 min |
| Jul 17, 10:52 AM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clark, Clay, Clinton, Coles and 32 more | 83 min |
| Jul 17, 1:25 PM CDT | Severe Thunderstorm Watch | SPC | Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 12 more | 6 hr |
| Jul 17, 1:33 PM CDT | Mesoscale Discussion | SPC | Bureau, Carroll, Henry, Jo Daviess, Knox, Mercer and 5 more | 117 min |
| Jul 17, 3:34 PM CDT | Mesoscale Discussion | SPC | Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 12 more | 86 min |
| Jul 16, 7:39 PM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 50 more | 96 min |
| Jul 17, 5:55 PM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 19 more | 95 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2007Severe Thunderstorm Watches in Illinois, 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.