The weather service issued a tornado watch for all but southern and southeastern Indiana through Thursday evening. Forecasters say the clash of the warm and cold air masses have created what's known as a particularly dangerous situation where several intense tornadoes are likely along with 80 mph winds and 2-inch diameter hail.
The watch will remain in effect for the following counties in northern Indiana until 4:00 p.m. CST: Adams, Allen, Blackford, Cass, DeKalb, Fulton, Grant, Huntington, Jay, Kosciusko, LaGrange, Miami, Noble, Steuben, Wabash, Wells, White and Whitley.
Weather Service meteorologist Dan McCarthy in Indianapolis says residents should assess their options for finding shelter in the event of a tornado or severe storm.
He says the warmer it gets Thursday the worse the storms will become. Thursday's highs are forecast to reach the upper 70s to lower 80s.
The Associated Press contributed to this report.