Is the polar vortex breaking up in november?

My feeds have been full of the polar vortex this week. Weather accounts post maps of a swirl over the Arctic tearing in two, with captions about the "earliest sudden stratospheric warming on record". Scientists post more careful versions of the same maps. Then the question comes from friends and family: does this mean a cold winter? I work on short-range forecasting, so the stratosphere is not my usual territory. Still, this is one of the few links we have between what happens 30 km up and the weather on the ground weeks later, and this year it is happening at a very odd time. So I sat down to work out what is going on, what is actually new about it, and what we can and cannot say about the winter. What the polar vortex isEvery autumn the Arctic loses the sun. The stratosphere over the pole, roughly 15 to 50 km up, cools fast, and the temperature difference between the pole and the mid-latitudes drives a ring of strong westerly winds around it. That ring and the cold air inside it is…

Commenting on Bubbles has been removed. Why? If you want to talk about this post, write to the author, use the comments on their blog if it has them, or reply with a "RE:" post on your own blog. Suggestions? feedback@bubbles.town