Wintry conditions sweep across the U.S., producing below-average temperatures, winter weather watches and flood watches.

A strong geomagnetic storm is forecast for Tuesday, according to the National Oceanic and Atmospheric Administration's Space Weather Prediction Center.

The National Weather Service has issued a Winter Weather Watch for almost every single county in our viewing area. A winter storm will race in early Tuesday. Snow will start before sunrise, beginning in central Pennsylvania by 3AM. It will be heavy at times through the morning.

A winter storm could bring heavy snow, a wintry mix and rain to Minnesota. Here's what to expect with Tuesday's storm.