Winter storm warnings have been issued in four states: Oregon, Washington, California and Minnesota. In northwestern Oregon and parts of Washington, including the Willapa Hills, there will be light snow showers until midnight Friday. Cities impacted include Mary's Peak, Brooklyn, Sunset Summit, Wilson River Summit, Valsetz, and Horton.

An active weather pattern is delivering back-to-back winter storms through the weekend. Here's what to expect.

Nearly half of the United States from the Midwest to Northeast will see snow or a freezing rain mix before the weekend arrives, weather forecasters say.