Alert archive / Illinois / Severe Thunderstorm Watches in 2007
Severe Thunderstorm Watch 598
The Storm Prediction Center issued this severe thunderstorm watch at Aug 15, 2007, 7:52 AM CDT for 26 counties in Illinois; 21 counties in Iowa. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 15, 2007, 7:52 AM CDT (12:52 UTC)
- Expired
- Aug 15, 2007, 1:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 70 kt
All 47 counties
Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Cedar County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Washington County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, DeKalb County, IL, Grundy County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McLean County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Whiteside County, IL, Winnebago County, IL, Woodford County, IL
The radar
The Quad Cities radar (KDVN), 56 km from the middle of the area, began a volume at 12:51 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
- 50%
- 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
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 15, 8:10 AM CDT | Severe Thunderstorm Warning | DVN | Buchanan | 65 min |
| Aug 15, 8:15 AM CDT | Severe Thunderstorm Warning | ARX | Fayette | 45 min |
| Aug 15, 8:20 AM CDT | Severe Thunderstorm Warning | DMX | Tama | 40 min |
| Aug 15, 8:53 AM CDT | Severe Thunderstorm Warning | DVN | Benton | 67 min |
| Aug 15, 8:59 AM CDT | Severe Thunderstorm Warning | DMX | Tama | 21 min |
| Aug 15, 9:41 AM CDT | Severe Thunderstorm Warning | DVN | Linn | 64 min |
| Aug 15, 10:11 AM CDT | Severe Thunderstorm Warning | DVN | Johnson | 44 min |
| Aug 15, 10:32 AM CDT | Severe Thunderstorm Warning | DVN | Cedar | 58 min |
| Aug 15, 11:19 AM CDT | Severe Thunderstorm Warning | DVN | Scott | 56 min |
| Aug 15, 12:09 PM CDT | Severe Thunderstorm Warning | DVN | Rock Island | 25 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, 0.9 hours before the alert went out and 57 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
- 1040 J/kg
- Mixed-layer CIN
- -200 J/kg
- Mixed-layer LCL
- 755 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 27 m²/s²
- 0-3 km storm-relative helicity
- 58 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 15, 7:15 AM CDT | Mesoscale Discussion | SPC | Carroll, Jo Daviess, Lee, Ogle, Stephenson, Whiteside and 1 more | 60 min |
| Aug 15, 7:50 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, Jo Daviess, Kane and 9 more | 55 min |
| Aug 15, 12:04 PM CDT | Mesoscale Discussion | SPC | Bureau, Henderson, Henry, Knox, Marshall, Mercer and 8 more | 86 min |
| Aug 15, 2:28 AM CDT | Mesoscale Discussion | SPC | Dickinson, Lyon, O'Brien, Osceola, Sioux | 92 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2007Severe Thunderstorm Watches in Iowa, 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.