Pattern Change 

Over the last few weeks we've been getting a few blasts of arctic air, but nothing long-lasting. Some warming has been taking place near the north pole, and that in turn displaces some of the true arctic air to the south. Some on our side of the world, some into Asia. We'll have another shot of some pretty cold air later this week and into the weekend, and most likely another later next week. But what's happening now at the pole should have a bigger impact locally later this month.

There's been more dramatic warming taking place over the north pole recently, and we're now seeing signs of what's called "blocking" setting up later this month. See the image to the left and above. This is showing the 10mb level of the atmosphere, or the true upper levels. With all of the red over the north pole, that means that the cold air is being displaced and sent south. As blocking sets up, which is a slowdown of the jetstream over Greenland, the cold air will move into the eastern U.S. and have no place to go.

So what we will likely see later this month and into February are repeated shots of cold air, and obviously more snow. Does that mean that big storms are possible? Yes. Is it definite? Absolutely not! It's just that pattern is going to become more favorable for cold air and snow. We'll likely have to deal with some lake-effect events for the second half of this month and into early February, until the lakes start to really cool off.

Just when you thought we'd get off pretty easy this year....