The forecast comes days after an expansive storm similarly trekked across the U.S. last week, unloading snow in the northern Plains and bringing tornadoes and wildfires to the South. At least five storm-related deaths in Nebraska and Mississippi were tied to that storm.

In some extreme cases, thunderstorms can spawn a derecho, a long-lived windstorm with gusts over 100 mph, strong enough to cause widespread destruction. If a severe thunderstorm warning mentions damaging winds or a derecho, take cover immediately—just as you would for a tornado.