Violent tornadoes ripped through parts of the U.S., wiping out schools and toppling semitractor-trailers in several states.

The severe storm threat begins Saturday. Central and northern MS face heightened risk, and forecasters are warning of danger across the state.

Jeff Smitherman, the director of an Alabama emergency management agency, joins ABC News live to discuss the high-risk alert for potential tornado outbreaks in Alabama and Mississippi.

Millions of Americans across the country are on alert for a severe weather outbreak as violent, long-track tornadoes with damaging winds of up to 80 mph and large hail are expected across the Midwest and South with the cross-country storm moving east.

President Donald Trump said in a post on his social media network that his administration is ready to assist affected communities.

Meanwhile, the severe weather threat will linger through Sunday from Florida northward into the upper Ohio River Valley, forecasters warned.