Alert archive / Illinois / Tornado Watches in 2025
Tornado Watch 157
The Storm Prediction Center issued this tornado watch at Apr 20, 2025, 9:01 PM CDT for 7 counties in Illinois. It was in force for 116 min.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2025, 9:01 PM CDT (02:01 UTC)
- Expired
- Apr 20, 2025, 10:57 PM CDT
- In force
- 116 min
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
Counties Ford County, IL, Grundy County, IL, Iroquois County, IL, Kankakee County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL
The radar
The Chicago radar (KLOT), 49 km from the middle of the area, began a volume at 02:01 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
- 30%
- One or more EF2 to EF5 tornadoes
- 10%
- Ten or more severe wind reports
- 20%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 40%
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Lincoln, IL (KILX), launched 00:00Z, 2.0 hours before the alert went out and 131 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
- 182 J/kg
- Mixed-layer CIN
- -136 J/kg
- Mixed-layer LCL
- 1336 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 377 m²/s²
- 0-3 km storm-relative helicity
- 580 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 4.9
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 7:46 PM CDT | Mesoscale Discussion | SPC | Alexander, Bond, Bureau, Cass, Christian, Clay and 60 more | 89 min |
| Apr 20, 9:48 PM CDT | Tornado Watch | SPC | Clay, Crawford, Edwards, Effingham, Gallatin, Hamilton and 10 more | 4 hr |
| Apr 20, 9:54 PM CDT | Mesoscale Discussion | SPC | DeKalb, Ford, Grundy, Iroquois, Kankakee, Kendall and 2 more | 96 min |
| Apr 20, 11:44 PM CDT | Mesoscale Discussion | SPC | Clay, Edwards, Effingham, Fayette, Franklin, Gallatin and 15 more | 91 min |
Nearby
Tornado Watches in Illinois, 2025Every tornado watch in 2025
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.