The last five winters have been dominated by periods of unseasonable warmth and brief chill. In three of those five seasons, snowfall was still above normal. Last year, however, we had our warmest and least snowy winter on record. So, what could change this winter? Unlike the last few winter seasons, waters over the eastern Pacific are now cooling, which means we’re going into a La Nina.
As we move into the winter months, we are seeing a La Nina pattern setting up. What does that mean across the country? It means a couple of things. One is that the colder air is going to be trapped over the northern Plains, while some of the milder air is over the southeast part of the country, including the Gulf coast. We’re in between that, with the jet stream riding right up into Pennsylvania. That will mean milder stretches of weather going into the winter, like we’ve seen so far in 2020. It also could mean that the colder air gets bottled up into Canada and the northern Plains, and doesn’t drift far enough south. Big snowstorms are going to be a challenge this winter, because of where the jet stream is located. That’s not to say we won’t get any snow, but major nor’easters or a lot of them just don’t seem to be in the cards here.
The state of the east central Pacific is an important driver for our winter pattern, but it’s not the only area of the world we look to.
While we consider the oceans, we also have to consider the ice and snow that are to the north of us. That is the cold air factory after all. Eurasian snow cover plus ice over the Arctic, and even snow over the lower 48 all remain below average. In addition to the lack of cold air over ice and snow, we are also seeing the jet stream keeping everything tighter to the north, not allowing that cold air to spin south other than just a few instances where we get a brief cold shot or two.
In the last ten winters, the North Atlantic Oscillation has been largely positive, which means winds over the Northern Atlantic blow faster, keeping most of the cold air north of our region. It appears the NAO will be largely positive again this winter, along with the Arctic Oscillation, which suggests the Polar Vortex will remain well north of our region as well. The one exception could be late December through January, where previous years with similar conditions suggest we’ll see an uptick in snow and cold outbreaks.
Putting it all together, it does look like we are heading into another mild winter. The average temperature is going to be anywhere between two and four degrees above normal. If you are a winter lover like us, there still is that chance of getting some of that cold, and our best chances for snow? That’s going to be happening during the month of January. January looks to be the snowiest month this season, which is pretty close to climatology. When we are talking about snow for the season, we are forecasting below normal snow again this year. This is not quite as low as last year, when we picked up five inches. This year, we’ll pick up between 15 and 25 inches, but that’s still below normal which is 30 inches in a given season. Along with the snow, we will see other types of wintry mixes and cold, rainy winter days, and that’s more than likely going to be more common than the snow.
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