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.

Unusually vicious and damaging weather across multiple U.S. states spawned violent tornadoes, blinding dust storms and fast-moving wildfires over the weekend, leaving at least 39 people dead.

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