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.

A sweeping storm system moving across the U.S. threatens to bring tornadoes, blizzards and possibly wildfires to different regions of the country.

A powerful storm is dropping drenching rain on flood-prone Southern California and heavy snow on the state’s mountains. It’s the first act of a storm that will unleash a severe thunderstorm outbreak,