Long-range pattern looking cold through December
A very strong, high-level blocking pattern, otherwise known in this case as the "Greenland block," will likely dominate through at least mid-month. This will create a very broad trough across North America, with the jet stream shifted well to the south. What this will do is force most of the Arctic air southward through western and central Canada then into southeastern Canada and the northeastern United States.
The main storm track will initially set up from the southern U.S. Plains to the Tennessee Valley next week before shifting toward the Middle Atlantic and Southeast U.S. coast the following week and perhaps beyond that.
The Greenland block tends to favor coastal storm development along or off the U.S. East Coast; however, the western North American ridge may not cooperate much with that idea as it does not look very strong and may be in the wrong position.
Any snow on the ground throughout a large portion of southern Canada during mid-month may have a good chance of holding on through Christmas Day with the widespread cold and low sun angle.
