If you live in New Jersey and you’re a snow lover, you’ll likely be stoked to hear about the latest weather pattern that’s shaping up in early 2021.
It always takes a lot of moving parts in the atmosphere for snowstorms to hit our region, but all the big pieces are starting to fall into place for what could be a snowy January and early February.
That’s the word from weather forecasters in the New Jersey region, including Jim Sullivan, a long-range meteorologist for WeatherWorks, a private forecasting company based in the Garden State.
While winter forecasting is a complicated job — because of the ever-changing weather patterns and slight shifts in things like the jet stream, the polar vortex and atmospheric “blocks” (more on that below) — those forces appear to be coming together to create ideal conditions for snowstorms in the eastern United States in the coming weeks.
“It’s a very favorable pattern,” Sullivan told NJ Advance Media on Thursday, when the calendar was getting ready to flip from 2020 to 2021. “It certainly increases the odds not only for snow, but for significant (winter) storms. It increases the odds significantly.”
Although the first week of January is expected to be milder than normal, with daytime temperatures in the mid-40s instead of the upper 30s, the nights will still be cold and computer guidance models are hinting at two potential winter storms — one late this week and one during the week of Jan. 11, Sullivan said.
Some parts of New Jersey could even get a light coating of snow from a storm system this Sunday that’s expected to bring rain to most of the state.
The polar vortex explained by experts at the National Weather Service.NOAA
Polar vortex and other factors
During recent days, the meteorology world has been buzzing about a significant force that could play a big role in stirring up snowstorms in the northern and eastern U.S. this month: The polar vortex.
That’s because the polar vortex — a huge mass of frigid air that circulates tightly around the North Pole — has started to break apart, Sullivan noted. This is something natural that happens periodically, and it allows cold air to drift down into the northern United States.
Cold air is a key ingredient in any snowstorm, which is why you’ll be hearing a lot about the polar vortex and its impact on our weather in coming weeks.
Another major factor in boosting our chances of snow is the formation of a weather pattern known as the North Atlantic Oscillation, or NAO. When the NAO turns to a negative phase, which is happening now, it basically shifts the polar jet stream and helps storms over the eastern U.S. slow down and grow stronger, Sullivan said.
With this type of pattern, a large ridge of high pressure in the upper atmosphere often remains centered near Greenland in the North Atlantic and stays in place for a long period. This type of setup, known as the “Greenland block,” allows cold air to flow down from Canada into the eastern region of the U.S., where it remains entrenched because the ridge near Greenland prevents the cold air from moving out.
This setup contributes to snowstorms when the cold air combines with moisture from the Atlantic Ocean.
Sullivan said some of the snowiest winters in the New Jersey region during the past 10 or 15 years — including the highly active winter of 2010-2011 — occurred when there was a prolonged Greenland block.
“The last time we had a good Greenland block was in March and April 2018, and it was very stormy,” he said.
That’s when New Jersey got blasted by four nor’easters in a matter of weeks, with one of those coastal storms dumping as much as 2 feet of snow on parts of Bergen, Essex and Morris counties.
No guarantees
While past history is no assurance that the same thing will happen, Sullivan says the weather pattern that is developing in early 2021 boosts the chances of snow in our region.
He says he is expecting winter storms to start ramping up by mid-January, with the cold and stormy pattern likely to continue into early February.
“Even though the pattern looks quite favorable (for snow), it’s hard to guarantee,” Sullivan noted. “We have to see how each storm plays out.”
However, if the current trends with the polar vortex and the Greenland block continue to take shape, Sullivan says the odds of snowstorms in New Jersey get much better.
So maybe it’s a good time to dig out those snowblowers that weren’t used last winter?
Current weather radar
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Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com. Tell us your coronavirus story or send a tip here.