The weather Sunday afternoon and evening was much more quiet, although quite a bit cooler, than Saturday evening as severe thunderstorms swept across northern Illinois and southern Wisconsin. Several severe thunderstorm and tornado warnings were issued, with two confirmed tornadoes in Boone County, along with straight line wind damage in Rockford.
According to Chicago National Weather Service, drone footage from the Rockford Fire Department, along with radar data, confirmed that a narrow swath of straight line winds of 70-80 mph occurred in the Mid-Town District of Rockford near the intersection of 9th Street and Broadway. The strong winds caused the roof of a building, south of Broadway, to blow off which then resulted in the collapse of some of the walls of the building. The roofing material from the building was blown to the north and northeast. Numerous power line poles and trees were also snapped along 9th Street, with additional roof damage to a home.
The severe storm that moved through Winnebago County traveled into Boone County where a tornado warning was issued for northern Boone County and far northwest McHenry County. In Boone County, it was determined that an EF-0 tornado, with peak winds of 80 mph, occurred near the intersection of Briar Cliff Street before lifting over Candlewick Lake. Several softwood trees were uprooted and snapped at the start of the tornado path and laid in a convergent pattern. There were also several floating docks that were flown across Candlewick Lake. The tornado was 60 yards wide and on the ground for approximately one minute.
Another brief spin-up tornado occurred further north in Boone County, just south of the Wisconsin/Illinois state line near Capron and rated an EF-U, which stands for ‘unknown’. This is because there was no clear indication or damage to give the tornado a rating. The brief tornado touched down in an open field near the intersection of Coon Trail and Capron Roads. Along with the tornadoes and straight line winds, there were also several reports of hail throughout the area.