SYRACUSE, NY (WSYR)- We are kicking off the beginning of Meteorological Winter this week as the calendar flips from November to December.
However, it looks like our chances for any meaningful winter weather could be lacking in the first half of the month of December. One of the main reasons snow lovers should curse this development is the arctic oscillation.
What exactly is the arctic oscillation?
Quite simply, the arctic oscillation (or AO) is a comparison of air pressure over the arctic region versus the North Atlantic and Pacific Oceans. When surface air pressures are low over the arctic and high over the ocean areas of the Northern Hemisphere we are in a ‘positive AO’ and when the pressures are flipped it is the ‘negative AO’ These changes in pressures are also tied to jet stream patterns here in the Northern Hemisphere.
Heading into early December there are strong signs from our computer models that we are headed into a positive phase.
What does a positive AO mean for our weather?
As the positive AO develops, we would expect the jet stream winds aloft to shift north of Central New York, especially later next week (week of December 6th). In addition, the Polar Vortex will be strong and anchored near the North Pole. It is when the AO becomes negative, and the Polar Vortex weakens that the Eastern United States (generally speaking) gets its coldest, snowiest winter weather.
While you can certainly get some winter weather with a positive AO, it is usually not long-lasting.
Early next week, beginning on Sunday, December 5, there are a couple of systems lurking in the eastern half of the country.
The overall trend is for the storm track to end up just to the west of Central New York making for main rainmakers for us. While there could be some snow at the start and end of each of these systems, we don’t feel at this point that the snow will have a major impact on us.
Check out our short-term discussion here to get more specifics on how each of these systems is expected to impact us.
Any hope for us snow lovers?
Not much in the next two weeks. Temperatures look to be above normal given the good agreement from our computer models. Beyond that things are up in the air. While our computer models are usually good at getting the overall pattern pegged for 10 to 14 days, any projections beyond that can get rather hazy.
You may hear chatter in the coming days about ‘changes’ to the Polar Vortex later in December but until we see computer models pointing that direction for several days in a row, we feel it would be premature to tout the return of the Polar Vortex here in the Eastern United States.
Plus, any change that does occur with the Polar Vortex happens first aloft in the stratosphere. We wouldn’t see any change to our weather patterns down near the ground, in the troposphere, for 10 days to two weeks later after any changes in the stratosphere. Realistically, any change to true prolonged winter weather would have to wait until early January 2022