Powerful storm threatens central US with snow and could become a bomb cyclone as it moves east

A strong winter storm is expected to impact a large swath of the US, bringing snow Thursday to the central region before forming into a bomb cyclone on its way east over the weekend.

About 11 million people were under winter weather alerts Thursday, stretching from western Illinois to parts of Utah and Arizona.

"There is increasing confidence that a significant winter storm will develop late Friday across the Southeast and then spread heavy snow across the interior eastern United States through Saturday," the National Weather Service said Wednesday in a tweet.