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.

A powerful strom system is forecast to sweep the south Friday and into the weekend, spreading the threat for severe weather all across portions of the US.

A dangerous storm system is expected to sweep through the St. Louis region Friday evening, bringing the potential for destructive winds and fast-moving tornadoes, with the metro area under a Level 4 out of 5 risk for severe weather.