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.

Storms with lightning and hail and at least one observed tornado were moving through the upper Midwest Monday with the potential for strong tornadoes. The National Weather Service said the highest risks — a 4 on a scale of 1 to 5 — were in portions of southern Minnesota,

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,

Tuesday is a KDKA First Alert Weather Day in the Pittsburgh area due to strong storms being possible. Extremely large hail, destructive straight-line winds, and even tornadoes will be possible. This is the first "enhanced" risk this year for the Pittsburgh area.

We have sunny and warm conditions in the forecast for Monday, with high temperatures in the mid-70s. But we are also tracking the chance for a few strong to severe storms across Mid-Michigan tomorrow afternoon.

After a beautiful day today, weather remains quiet and not too cold tonight. Mostly clear skies and lows in the 40s. Tomorrow, we start out the day with plenty of