Millions in the Upper Midwest face the possibility of a severe thunderstorm outbreak Monday—the start of several days of extreme weather threats across the country this week.

Monday is probably the peak of this event, but a concerning storm risk shifts eastward Tuesday. Cities in the highest risk for tornadoes include Minneapolis and Rochester in Minnesota and La Crosse in Wisconsin.

A big storm is across the center of the U.S. Monday, April 28, spelling strong storm systems for the northern tip of the Midwest all the way down into Texas. Severe storms are brewing over a large swath of Texas on the first day of the work week which could bring large hail and damaging winds to areas already seeing severe weather season in full swing.