Alert archive / Illinois / Tornado Watches in 2023
Tornado Watch 154
The Storm Prediction Center issued this tornado watch at Apr 20, 2023, 2:06 PM CDT for 37 counties in Illinois; 8 counties in Iowa; 20 counties in Wisconsin. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2023, 2:06 PM CDT (19:06 UTC)
- Expired
- Apr 20, 2023, 8:00 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 65 counties
Clinton County, IA, Des Moines County, IA, Henry County, IA, Jackson County, IA, Lee County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McDonough County, IL, McHenry 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, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Marquette County, WI, Milwaukee County, WI, Ozaukee County, WI, Racine County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI
The radar
The Milwaukee radar (KMKX), 82 km from the middle of the area, began a volume at 19:09 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
- 50%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
43 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 2:15 PM CDT | Severe Thunderstorm Warning | DVN | Hancock, McDonough | 60 min |
| Apr 20, 2:17 PM CDT | Tornado Warning | DVN | Hancock, Henderson | 43 min |
| Apr 20, 2:51 PM CDT | Severe Thunderstorm Warning | DVN | Mercer | 24 min |
| Apr 20, 3:05 PM CDT | Severe Thunderstorm Warning | DVN | Henry, Mercer, Rock Island | 40 min |
| Apr 20, 3:05 PM CDT | Severe Thunderstorm Warning | DVN | Henderson, Warren | 40 min |
| Apr 20, 3:10 PM CDT | Severe Thunderstorm Warning | DVN | McDonough | 35 min |
| Apr 20, 3:10 PM CDT | Severe Thunderstorm Warning | DVN | Carroll, Whiteside | 35 min |
| Apr 20, 3:14 PM CDT | Tornado Warning | DVN | McDonough | 20 min |
| Apr 20, 3:16 PM CDT | Severe Thunderstorm Warning | ILX | Fulton, Schuyler | 29 min |
| Apr 20, 3:21 PM CDT | Tornado Warning | DVN | Henry, Mercer | 39 min |
| Apr 20, 3:25 PM CDT | Severe Thunderstorm Warning | DVN | Henry, Mercer, Warren | 50 min |
| Apr 20, 3:31 PM CDT | Severe Thunderstorm Warning | ILX | Knox | 29 min |
| Apr 20, 3:33 PM CDT | Severe Thunderstorm Warning | DVN | Carroll, Stephenson, Whiteside | 42 min |
| Apr 20, 3:34 PM CDT | Tornado Warning | ILX | Fulton | 26 min |
| Apr 20, 3:46 PM CDT | Severe Thunderstorm Warning | DVN | Bureau, Henry, Whiteside | 29 min |
| Apr 20, 3:53 PM CDT | Severe Thunderstorm Warning | DVN | Whiteside | 34 min |
| Apr 20, 3:56 PM CDT | Tornado Warning | DVN | Carroll, Whiteside | 22 min |
| Apr 20, 3:56 PM CDT | Severe Thunderstorm Warning | ILX | Knox, Stark | 38 min |
| Apr 20, 3:59 PM CDT | Severe Thunderstorm Warning | ILX | Fulton, Peoria, Tazewell | 31 min |
| Apr 20, 4:00 PM CDT | Severe Thunderstorm Warning | LOT | Lee, Ogle | 75 min |
| Apr 20, 4:05 PM CDT | Severe Thunderstorm Warning | DVN | Bureau, Henry | 40 min |
| Apr 20, 4:16 PM CDT | Severe Thunderstorm Warning | MKX | Dane, Green, Jefferson, Rock | 33 min |
| Apr 20, 4:19 PM CDT | Tornado Warning | DVN | Bureau, Henry | 26 min |
| Apr 20, 4:28 PM CDT | Severe Thunderstorm Warning | ILX | Fulton, Mason, Peoria, Tazewell, Woodford | 32 min |
| Apr 20, 4:29 PM CDT | Tornado Warning | DVN | Bureau | 15 min |
| Apr 20, 4:36 PM CDT | Severe Thunderstorm Warning | DVN | Bureau, Putnam | 39 min |
| Apr 20, 4:49 PM CDT | Tornado Warning | ILX | Peoria, Tazewell, Woodford | 26 min |
| Apr 20, 4:55 PM CDT | Severe Thunderstorm Warning | ILX | Fulton, Marshall, Peoria, Tazewell, Woodford | 51 min |
| Apr 20, 4:55 PM CDT | Severe Thunderstorm Warning | LOT | DeKalb, LaSalle, Lee | 52 min |
| Apr 20, 4:56 PM CDT | Flash Flood Warning | ILX | Fulton, Peoria, Tazewell, Woodford | 2 hr |
| Apr 20, 5:02 PM CDT | Severe Thunderstorm Warning | LOT | Boone, McHenry, Winnebago | 31 min |
| Apr 20, 5:06 PM CDT | Severe Thunderstorm Warning | ILX | Fulton, Mason, Schuyler | 41 min |
| Apr 20, 5:14 PM CDT | Severe Thunderstorm Warning | LOT | DeKalb, Kane | 46 min |
| Apr 20, 5:15 PM CDT | Severe Thunderstorm Warning | LOT | LaSalle, Livingston | 60 min |
| Apr 20, 5:17 PM CDT | Severe Thunderstorm Warning | MKX | Rock, Walworth | 28 min |
| Apr 20, 5:40 PM CDT | Severe Thunderstorm Warning | LOT | Cook, Kane, Lake, McHenry | 50 min |
| Apr 20, 6:06 PM CDT | Severe Thunderstorm Warning | LOT | Grundy, Kankakee, Livingston, Will | 54 min |
| Apr 20, 6:06 PM CDT | Severe Thunderstorm Warning | LOT | DuPage | 24 min |
| Apr 20, 6:19 PM CDT | Severe Thunderstorm Warning | MKX | Milwaukee, Waukesha | 26 min |
| Apr 20, 6:22 PM CDT | Severe Thunderstorm Warning | LOT | Cook, DuPage, Lake | 26 min |
| Apr 20, 6:28 PM CDT | Severe Thunderstorm Warning | LOT | Cook, DuPage, Will | 50 min |
| Apr 20, 6:47 PM CDT | Severe Thunderstorm Warning | LOT | Kankakee, Will | 43 min |
| Apr 20, 6:56 PM CDT | Severe Thunderstorm Warning | MKX | Fond du Lac, Sheboygan | 34 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, 7.1 hours before the alert went out and 142 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1350 m above ground
- 0-6 km bulk shear
- 60 kt
- 0-1 km storm-relative helicity
- 44 m²/s²
- 0-3 km storm-relative helicity
- 166 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 |
|---|---|---|---|---|
| Apr 20, 12:25 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Cass, Greene, Hancock and 6 more | 2 hr |
| Apr 20, 1:20 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Bond, Brown, Calhoun, Cass, Christian and 26 more | 7 hr |
| Apr 20, 1:50 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DuPage, Grundy and 21 more | 85 min |
| Apr 20, 3:10 PM CDT | Mesoscale Discussion | SPC | Bond, Brown, Calhoun, Cass, Christian, Clinton and 16 more | 95 min |
| Apr 20, 3:41 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DuPage, Fulton and 24 more | 94 min |
| Apr 20, 5:23 PM CDT | Mesoscale Discussion | SPC | Boone, Cook, DeKalb, DuPage, Ford, Grundy and 18 more | 97 min |
| Apr 20, 5:36 PM CDT | Mesoscale Discussion | SPC | Alexander, Bond, Calhoun, Cass, Christian, Clark and 43 more | 84 min |
| Apr 19, 8:21 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Boone, Calhoun, Carroll and 18 more | 3 hr |
| Apr 19, 10:58 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Benton, Black Hawk, Boone, Bremer, Buchanan and 23 more | 7 hr |
| Apr 19, 11:53 PM CDT | Severe Thunderstorm Watch | SPC | Fremont, Mills, Montgomery, Page, Pottawattamie | 6 hr |
| Apr 20, 1:28 AM CDT | Mesoscale Discussion | SPC | Fremont, Page | 2 hr |
Nearby
Tornado Watches in Illinois, 2023Tornado Watches in Wisconsin, 2023Tornado Watches in Iowa, 2023Every tornado watch in 2023
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.