WASHINGTON | A gigantic line of powerful thunderstorms could affect one in five Americans on Wednesday as it rumbles from Iowa to Maryland packing hail, lightning and tree-toppling winds.
Meteorologist are warning that the continuous line of storms may even spawn an unusual weather event called a derecho, which is a massive storm of strong straight-line winds spanning at least 240 miles. Wednesday's storms are also likely to generate tornadoes and cause power outages that will be followed by oppressive heat, said Bill Bunting, operations chief at the National Weather Service's Storm Prediction Center in Norman, Okla.