High heat and humidity expand from the Northwest into the central U.S. and lower Mississippi Valley this week with temperatures in the high 90s to 100-degree range.
Thunderstorms with the risk of heavy rain continue over parts of the Southwest and California. Flood watches are posted.
A front moving into the upper Midwest traveling across the Great Lakes will bring some strong to severe storms today and Tuesday.
The main risks will be strong winds, hail and isolated tornadoes.
Upper-level winds will push some of the smoke from wildfires into the Northern Tier of the country in the next few days.