A powerful storm system moved across eastern Iowa into southwest Wisconsin, sweeping a strong cold front through the area during the afternoon hours of Thursday, April 20th. A line of thunderstorms developed quickly along the front, with some of them surpassing severe thresholds producing hail up to the size of a golf ball.
An EF1 tornado tracked to the northeast for about 6 miles starting just east of Morrison, IL just before 3 PM CST.

Hail in MERCER, ILLINOIS
From 20-APR-23 14:13:00 to 20-APR-23 14:13:00 (CST-6)
Location: SHERRARD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in HENRY, ILLINOIS
From 20-APR-23 14:21:00 to 20-APR-23 14:21:00 (CST-6)
Location: OSCO
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Tornado in WHITESIDE, ILLINOIS
From 20-APR-23 14:56:00 to 20-APR-23 15:03:00 (CST-6)
Location: MORRISON
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

An isolated tornado began just east of Morrison IL around 2:56 PM CST. The tornado damaged a power pole and a tree at this location. The tornado then caused sporadic damage until it approached Fulfs Road.  It strengthened at this location and caused damage to trees, farm outbuildings, and a power pole. The tornado ended shortly after this location. Wind speeds are estimated in the 105-110 MPH range, with a rating of EF1. At it's widest, the tornado was 300 yards and was likely a multi-vortex tornado. The tornado path length was nearly 6 miles.

Hail in MCDONOUGH, ILLINOIS
From 20-APR-23 14:05:00 to 20-APR-23 14:10:00 (CST-6)
Location: INDUSTRY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported that the hail lasted for 5 minutes and nearly covered the ground.

Hail in HENRY, ILLINOIS
From 20-APR-23 14:20:00 to 20-APR-23 14:20:00 (CST-6)
Location: ORION
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A public photo of golf ball sized hail.  The report was relayed via broadcast media.

Hail in HENRY, ILLINOIS
From 20-APR-23 14:37:00 to 20-APR-23 14:37:00 (CST-6)
Location: GENESEO
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in HENRY, ILLINOIS
From 20-APR-23 14:45:00 to 20-APR-23 14:45:00 (CST-6)
Location: GENESEO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail in HENRY, ILLINOIS
From 20-APR-23 15:02:00 to 20-APR-23 15:02:00 (CST-6)
Location: GALVA
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The Emergency Manager reported nickel size hail 1.5 miles southwest of Galva.

Hail in HENRY, ILLINOIS
From 20-APR-23 15:16:00 to 20-APR-23 15:16:00 (CST-6)
Location: KEWANEE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in HENRY, ILLINOIS
From 20-APR-23 15:03:00 to 20-APR-23 15:03:00 (CST-6)
Location: GALVA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The time of the event was estimated using radar.

Hail in BUREAU, ILLINOIS
From 20-APR-23 15:23:00 to 20-APR-23 15:23:00 (CST-6)
Location: NEPONSET
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in MERCER, ILLINOIS
From 20-APR-23 14:15:00 to 20-APR-23 14:15:00 (CST-6)
Location: SHERRARD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 20-APR-23 15:00:00 to 20-APR-23 15:00:00 (CST-6)
Location: MALVERN
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A public report of power poles down at this location.

Hail in HENRY, ILLINOIS
From 20-APR-23 14:20:00 to 20-APR-23 14:20:00 (CST-6)
Location: ORION
Magnitude: 3.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported mostly quarter size hail but a few stones were up to 3.0 inches in diameter. The time of the event was estimated using radar.

Hail in BUREAU, ILLINOIS
From 20-APR-23 15:48:00 to 20-APR-23 15:48:00 (CST-6)
Location: PRINCETON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in BUREAU, ILLINOIS
From 20-APR-23 15:29:00 to 20-APR-23 15:29:00 (CST-6)
Location: SHEFFIELD
Magnitude: 54.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A 4 inch diameter tree branch was knocked down.

Hail in MCDONOUGH, ILLINOIS
From 20-APR-23 14:08:00 to 20-APR-23 14:08:00 (CST-6)
Location: INDUSTRY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MCDONOUGH, ILLINOIS
From 20-APR-23 14:12:00 to 20-APR-23 14:12:00 (CST-6)
Location: INDUSTRY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported that hail size has increased to quarters.

Hail in CARROLL, ILLINOIS
From 20-APR-23 14:41:00 to 20-APR-23 14:41:00 (CST-6)
Location: MT CARROLL
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in HENRY, ILLINOIS
From 20-APR-23 15:05:00 to 20-APR-23 15:05:00 (CST-6)
Location: GALVA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The Emergency Manager reported quarter size hail 1.5 miles southwest of Galva.

Hail in HENRY, ILLINOIS
From 20-APR-23 15:13:00 to 20-APR-23 15:13:00 (CST-6)
Location: KEWANEE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The time of the event was estimated using radar.