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.

Multiple rounds of severe thunderstorms are expected across the central U.S. on Monday, some capable of producing damaging winds, large hail and strong tornadoes, forecasters say. According to the National Weather Service,

The severe weather threat extends beyond the Upper Midwest, affecting more than 45 million people from Texas to the U.S.-Canada border.