EF1 tornado in Winnebago County, Illinois

This tornado began southwest of the intersection of Elmwood Rd and Rockton Ave on the north side of Rockford and tracked northeastward for almost 9 miles, straddling the Rock River as it tracked through the west side of Machesney Park before weakening and lifting over Roscoe. This tornado caused damage to several trees and outbuildings, as well as multiple homes, which primarily suffered roof damage. A couple of homes had entire portions of their roofs removed where the tornado was at its peak intensity and featured 90-100 mph winds.

During the afternoon and evening of the 31st, a wave of severe thunderstorms produced numerous tornadoes, severe hail, extensive wind damage, and localized flooding across northern and northeastern Illinois. A total of 37 tornadoes were confirmed across the state. The NWS Chicago office tied a record for the most tornadoes to occur in a single calendar day within the office's county warning area with 22, 17 of which occurred in Illinois. One EF-2 tornado occurred in south-central Lee County and two others in northwest Indiana. Some of the more notable damage includes multiple semi trucks blown over, a garage that had been completely destroyed southeast of Amboy, and the partial roof collapse of the Apollo Theatre in Belvidere which unfortunately resulted in one fatality and 40 injuries.