Weekly long-range update into early January

Most of the Arctic air is expected to retreat back up into the northern two-thirds of Canada after the 20th as a more westerly flow of air takes hold across southern Canada and the United States. This will allow milder, Pacific air to penetrate well into North America for the last 10 days of December, with just brief shots of cold mixed in.

This pattern should also open the door to several quick-moving storms across the country.