A cross-country storm will explode in strength as it moves over the central United States Friday, delivering extreme weather to millions through the weekend, including the chance of multiple strong tornadoes.

Dangerous weather conditions will peak Saturday, with one of the most prolific tornado-producing setups in years expected to develop over the Deep South — with disastrous results likely.

More than 100 million people are being urged to prepare for a potentially dangerous weather outbreak that could unleash thunderstorms capable of producing hurricane-force wind gusts and

The threat of tornadoes moved east into the Mississippi Valley and the south on Saturday, just a day after a massive storm in several central states.