Across the United States, 33 million people face the risk of severe weather Sunday.
The greatest potential for severe storms will be from parts of southeast Oklahoma into northeast and east-central Texas.
The storms could spark tornadoes, particularly over northeast Texas.
Large hail could also slam parts of the region.
The threat will move east Monday, including the cities of Cleveland, Houston and Memphis, Tennessee.
On Saturday a tornado that struck Eastland County, Texas, west of the Dallas-Fort Worth area, killed one person and injured another critically, according to the local fire department.
Meanwhile, an intense late-season winter storm is moving over the Central Rockies and into the Plains. The mountains near Crestone, Colorado, have seen more than 17 inches of snow.
Parts of Wyoming and Nebraska are also getting hit, with heavy snow and reduced visibility making travel extremely dangerous.
Separately, Tropical Storm Ana made landfall early Sunday in South Carolina.