Forecasters say portions of the central United States could see severe weather this weekend and Monday.

The Storm Prediction Center at Norman, Oklahoma said Wednesday a bout of “fairly substantial” severe weather is possible in Kansas, Nebraska and the Dakotas on Saturday, from Oklahoma to Iowa on Sunday and from Oklahoma to Illinois on Monday.

Storms could become steadily worse through the period — starting with hail and high winds Saturday and evolving into a system with tornadoes possible by Monday in Arkansas, Illinois, Iowa, Kansas, Missouri and Oklahoma.

The severe weather could extend into Tuesday but forecasters said a longer term storm prediction was not possible yet.

Tornadoes that ripped through East Texas Wednesday night left at least six people dead.