Alert archive / Illinois / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 423
The Storm Prediction Center issued this severe thunderstorm watch at Jul 19, 2017, 5:45 PM CDT for 23 counties in Illinois; 9 counties in Iowa; 14 counties in Wisconsin. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 19, 2017, 5:45 PM CDT (22:45 UTC)
- Expired
- Jul 20, 2017, 12:00 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 70 kt
All 46 counties
Buchanan County, IA, Cedar County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Jackson County, IA, Jones County, IA, Linn County, IA, Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Columbia County, WI, Dane County, WI, Dodge County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Sauk County, WI, Walworth County, WI, Waukesha County, WI
The radar
The Milwaukee radar (KMKX), 121 km from the middle of the area, began a volume at 22:44 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
- 10%
- Ten or more severe wind reports
- 80%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 90%
Warnings issued inside it
16 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 19, 5:59 PM CDT | Severe Thunderstorm Warning | DVN | Buchanan, Delaware, Dubuque | 61 min |
| Jul 19, 6:32 PM CDT | Severe Thunderstorm Warning | MKX | Iowa, Lafayette, Sauk | 73 min |
| Jul 19, 6:42 PM CDT | Severe Thunderstorm Warning | DVN | Carroll, Jo Daviess, Stephenson | 78 min |
| Jul 19, 7:01 PM CDT | Tornado Warning | MKX | Iowa, Sauk | 29 min |
| Jul 19, 7:03 PM CDT | Severe Thunderstorm Warning | DVN | Delaware, Dubuque, Jackson, Jones, Linn | 57 min |
| Jul 19, 7:10 PM CDT | Severe Thunderstorm Warning | MKX | Dane, Green, Rock | 80 min |
| Jul 19, 7:21 PM CDT | Severe Thunderstorm Warning | LOT | Ogle, Winnebago | 54 min |
| Jul 19, 7:24 PM CDT | Severe Thunderstorm Warning | MKX | Columbia, Sauk | 81 min |
| Jul 19, 7:48 PM CDT | Tornado Warning | MKX | Dane, Green, Rock | 42 min |
| Jul 19, 7:53 PM CDT | Severe Thunderstorm Warning | MKX | Jefferson, Rock, Walworth | 67 min |
| Jul 19, 7:54 PM CDT | Severe Thunderstorm Warning | LOT | Boone, DeKalb, Lee, McHenry, Ogle, Winnebago | 51 min |
| Jul 19, 8:16 PM CDT | Tornado Warning | LOT | Boone, DeKalb, Ogle, Winnebago | 29 min |
| Jul 19, 8:30 PM CDT | Severe Thunderstorm Warning | LOT | DeKalb, LaSalle, Lee | 30 min |
| Jul 19, 8:34 PM CDT | Severe Thunderstorm Warning | LOT | Boone, Cook, DeKalb, DuPage, Kane, Kendall and 4 more | 56 min |
| Jul 19, 8:37 PM CDT | Severe Thunderstorm Warning | MKX | Kenosha, Racine, Walworth | 26 min |
| Jul 19, 9:08 PM CDT | Severe Thunderstorm Warning | LOT | Cook, DuPage, Grundy, Kendall, Will | 67 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, 10.8 hours before the alert went out and 120 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
- 147 J/kg
- Mixed-layer CIN
- -138 J/kg
- Mixed-layer LCL
- 1286 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 56 m²/s²
- 0-3 km storm-relative helicity
- 96 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 19, 5:11 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, Jo Daviess, Lee and 5 more | 34 min |
| Jul 19, 12:11 PM CDT | Mesoscale Discussion | SPC | Bremer, Buena Vista, Butler, Cerro Gordo, Cherokee, Chickasaw and 20 more | 2 hr |
| Jul 19, 12:36 PM CDT | Severe Thunderstorm Watch | SPC | Bremer, Butler, Cerro Gordo, Clay, Dickinson, Emmet and 7 more | 5 hr |
| Jul 19, 2:38 PM CDT | Mesoscale Discussion | SPC | Allamakee, Chickasaw, Howard, Winneshiek | 2 hr |
| Jul 19, 3:29 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Chickasaw, Clayton, Fayette, Floyd, Howard and 2 more | 6 hr |
| Jul 19, 4:52 PM CDT | Severe Thunderstorm Watch | SPC | Lyon, Plymouth, Sioux, Woodbury | 6 hr |
| Jul 19, 6:32 PM CDT | Mesoscale Discussion | SPC | Allamakee, Chickasaw, Clayton, Fayette, Floyd, Howard and 2 more | 58 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2017Severe Thunderstorm Watches in Wisconsin, 2017Severe Thunderstorm Watches in Iowa, 2017Every severe thunderstorm watch in 2017
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.