According to the SPC: “The HIGH risk area almost always means a major severe weather outbreak is expected, with great coverage of severe weather and enhanced likelihood of extreme severe (i.e., violent tornadoes or extreme convective wind events over a large area).”

About 47 million people faced an enhanced to moderate severe storm threat from Madison, Wisconsin, to Birmingham, Alabama.

A huge storm system crossing the U.S. threatens to unleash tornadoes Friday in the Mississippi Valley, blizzards in the northern Plains and dry, gusty conditions in Texas and Oklahoma that pose a high risk of wildfires.