Back-to-back winter storms are predicted to affect 29 million Americans across the country. Here’s the latest from the National Weather Service. The National Weather Service has issued a winter storm watch from Tuesday morning until Wednesday morning,

Two winter storm systems are on the way this week, both bringing the potential for accumulating snow and major travel problems. The first big one will hit Chicago on Wednesday. Widespread accumulating snow is expected in the late morning and lasting through the afternoon and evening.

A winter storm watch is usually issued when a storm system is one to two days from starting. This long lead time is used to help you get ready if you have to make travel or work changes. Eventually as the storm gets closer, the winter storm watch either turns to a winter storm warning or a winter weather advisory.