As millions of Americans hunker down for the winter storm, 19 states and Washington, D.C., have declared states of emergency.

Track everything from current conditions, forecast timing and potential impacts from the winter storm here.

A snow system develops over Cincinnati Tuesday, with heavy showers expected for most of the late morning and early afternoon.

Track the winter storm as it's forecasted to bring heavy snow and extremely cold weather to the U.S., reaching millions from ...