Thunderstorm Wind in Bureau County, Illinois

Large tree limbs blown down by thunderstorm winds.

Very hot and humid air in place across eastern Iowa, northwest Illinois, and far northeast Missouri interacted with a southward moving frontal boundary and disturbance aloft, setting the stage for development and organization of severe thunderstorms across the region. Storms initially formed from north central Iowa and southern Wisconsin along the frontal boundary, which slowly worked south into the hot, humid air in place across the region. As storms arrived across east central Iowa, they began producing winds around 70 MPH across the Hwy 20 corridor. Another storm to the south further intensified, and began producing winds of 80+ MPH as it tracked along the Hwy 30 corridor. This impacted the northern suburbs of Cedar Rapids into Clinton. These storms continued to produce wind gusts around 60-70 MPH as they progressed into northwest Illinois. One brief EF-0 tornado began in Clinton, Iowa, then moved across the Mississippi River before dissipating near Fulton, Illinois. Damage near Andrew, Iowa in Jackson County was determined to be straight-line winds. Storms additionally produced large hail around the Dubuque metro, with quarter size hail reported.