Coldest air likely to hang out across western Canada through early February

As I stated in my BrettAWX twitter feed, the overall jet stream pattern if you just looked at the eastern half of North America would tell me to expect sustained cold and significant coastal storms over the next few weeks due to significant high latitude blocking. However, in order to have the sustained cold and storms, you need cooperation from the western North American pattern as well, and from what I have been seeing, that does not appear to be the case.

If you are rooting for cold and snow in the East, you want to also see a significant high pressure ridge over the Rockies, which there is no indication of through early February. A strong ridge over the Rockies allows a continuous stream of cold, Arctic air into the East. It also allows the jet stream to potentially become amplified like a tall roller coaster, with a significant dip in the East. This dip can favor the development of strong coastal storms, which can bring significant snowfall.

Without the ridge in the Rockies, we have more of a Pacific influence of air coming across the lower 48 states. It also prevents significant amplification of the jet stream in East, leading to more of a flatter jet stream pattern with weaker storms.

So overall, for southeastern Canada and the northeastern quarter of the United States, I see periodic cold shots, but no sustained, extreme cold outbreaks. There can be several storms moving through the region but probably no blockbusters. There will still be opportunities for some snow and ice as the air looks just cold enough for many areas, and we are also heading into normally the coldest and snowiest part of the winter along the coast.

Where will the Arctic air go? Signs continue to point toward western Canada and eastern Alaska over the next few weeks.

On a positive note (drought relief), the pattern does favor above-normal precipitation for Central and Northern California for the end of January and early February.

As we get deeper into February, I expect the high-latitude blocking pattern to break down as it can go on only so long, which gives me confidence that much of northern U.S. and eastern Canada will not surprisingly end up warmer than normal for the winter as a whole.