Five Northeast states from New York to Maine are under a wind chill advisory.

Five Northeast states are under wind chill advisories Thursday morning as the coldest air of the season slams the region.

Wind chills plunged Thursday morning to minus 4 degrees in Boston, 5 degrees in New York City, minus 5 degrees in Syracuse and 12 degrees in Pittsburgh.

The cold blast even extends to the South. Wind chills fell to 20 degrees in Charlotte, 15 degrees in Knoxville, 21 degrees in Birmingham and 32 degrees in Charleston.

The bitter temperatures come after a snow squall moved through the Northeast Wednesday afternoon.

The quick burst of snow brought gusty winds and reduced visibility to Philadelphia, New York City and Boston.

At least two people died in a multi-car crash on a Pennsylvania interstate during a snow squall Wednesday.

This cold will not last long in the Northeast and the South – a warm-up is expected for the weekend and just in time for Christmas.

But the West Coast may get a travel mess over the holidays. A series of storms is threatening to bring flooding, mudslides and heavy mountain snow to Washington, Oregon and Northern California.

By Sunday and the start of the holiday week, heavy rain is expected in California with heavy mountain snow. Travel could be impacted in San Francisco by Sunday morning.

Up to 6 inches of heavy rain is possible on the West Coast, with the threat of flooding and mudslides. In the mountains, some areas could see as much as 5 feet of snow.

Along the Washington and Oregon coast, winds could gust as high as 60 mph, with wind damage possible.