The forecast hinges on a layer of cold air near the surface. In the South, winter precipitation often fails to accumulate because the ground is too warm. This time, however, it is cold, and forecasters are concerned.

The major storm is set to hit starting on Jan. 23 and will stretch into the weekend, spreading snow and ice from the southern Plains to the Northeast.

Follow as a winter storm is expected to bring heavy snowfall, icy roads and cold temperatures from the southern states to the Northeast.