Several areas of the country face threats Friday. The most significant threat for tornadoes will be across central Nebraska.
Nebraska, northern Kansas and eastern Colorado are under a tornado watch until 10 p.m. CST, said CNN meteorologist Haley Brink. The Northern Plains, Mid-Atlantic and Texas are under severe storm watches, Brink said. Golf ball-sized hail has been reported in the Northern Plains.
More than 50 million people could be affected based on areas at risk for severe weather, according to the National Weather Service Storm Prediction Center.
Storms will likely affect populated areas such as Dallas, Houston and Oklahoma City. The threats include damaging winds, tornadoes and large hail that could exceed the size of a tennis ball or baseball.
On Sunday, the storm system is expected to continue east, targeting Midwest states such as Illinois, Indiana and Michigan.
On the heels of this system, yet another potential significant storm event will appear early next week for portions of the southern Plains and Mississippi Valley.
Flooding remains a concern. Two to 4 inches of rain is expected to fall on already saturated ground across the Central Plains and Upper Midwest.
CNN's Dave Hennen and Monica Garrett contributed to this report.