Millions of people in Texas, Ohio, Tennessee, Nebraska and Oklahoma are bracing for dangerous conditions as forecasters warn of possible tornadoes, 80-mph wind gusts, flooding and hail as the extreme weather outbreak rolls into its sixth week.

About 18 million people are at risk for severe storms Monday night across the Central Plains in areas like North Texas and South Dakota and eastbound into Illinois.

The cities most at risk include Oklahoma City and Tulsa, Oklahoma; Wichita, Kansas; Omaha…