Forecasters say one of the key factors driving the weather is an atmospheric river, which is a long band of water vapor that can transport moisture from the tropics to more northern areas.

Many states across the central and eastern United States face wild weather this week, including an atmospheric river and temperature swings. See how in seven maps.

The words "bomb" and "cyclone" are bad enough on their own. What does it mean when they're used to describe a storm?