"All of the sudden these storms busted through," ABC7 Meteorologist Mike Caplan said. "Large hail is going to be possible, and also tornadoes."
The severe weather led Metra to hold all outbound trains at Union Station due to high winds. Airlines also preemptively canceled 328 flights at O'Hare International Airport; No flights have been canceled at Midway. The White Sox game at U.S. Cellular Field was also canceled, along as an opening night concert at Chicago's Millennium Park.
Several small tornadoes, quarter-sized hail and winds of up to 70 mph were reported. Emergency officials say tornadoes touched down in Winnebago County, but no damage was reported.
The storms are part of a major system moving across the Midwest.
A Severe Thunderstorm Warning is in effect for Cook, DuPage, and Kane County in Illinois until 6 p.m.
A Tornado Warning is in effect in Kendall County until 6 p.m. During a Tornado Warning, residents should take cover by moving into an interior room on the lowest floor of a sturdy building and avoiding windows. If in a mobile home, vehicle or outdoors, please seek shelter and protect yourself from flying debris.
A Thunderstorm Warning is in effect until 5:45 p.m. for Kendall County.
Tennis-ball sized hail and 70mph winds are reported by trained weather spotters.
A Tornado Watch is in effect until 9 p.m. for several counties in Illinois, including Grundy; Kane; Kendall; Livingston; McHenry; Boone; De Kalb; La Salle; Lee; Ogle; and Winnebago. Several Wisconsin counties - Dane; Green; Iowa; Jefferson; Lafayette; Rock; Sauk; Walworth- are also under a Tornado Watch until 9 p.m.
A Severe Thunderstorm Watch is in effect until 1 a.m. for Cook, DuPage, Ford, Iroquois, Kankakee, Lake and Will counties in Illinois.
In Indiana, a Severe Thunderstorm Watch is in effect until 2 a.m. for Adams; Allen; Benton; Blackford; Carroll; Cass; De Kalb; Elkhart; Fulton; Grant; Howard; Huntington; Jasper; Jay; Kosciusko; La Porte; Lagrange; Lake; Marshall; Miami; Newton; Noble; Porter; Pulaski; St. Joseph; Starke; Steuben; Wabash; Wells; White; Whitley counties.
In Wisconsin, a Severe Thunderstorm Watch is in effect until 1 a.m. for Columbia; Dodge; Fond du Lac; Green Lake; Kenosha; Marquette; Milwaukee; Ozaukee; Racine; Sheboygan; Washington; Waukesha counties.