A big pattern change will funnel Arctic air into the US. Here’s where temperatures will drop

(CNN) — A big pattern change is on the way for the United States with a blast of Arctic air set to bring a first taste of winter to millions.

It all starts this weekend as a cold front allows December-like air from near the North Pole to start spreading into the northern US. This front will push farther south and east through the weekend, and temperatures could drop 10 to 15 degrees below normal almost everywhere east of the Rockies by Sunday night.

These winter-like conditions — with the coldest temperatures of the season — could make it as far south as the Gulf Coast early next week.

The brief pattern flip could also potentially switch on the lake-effect snow machine for the first time this season and bring some measurable snow downwind of the Great Lakes.

Here’s how this chilly c