STATEN ISLAND, NY — If you’ve been watching winter forecastsyou’ve probably heard the term “polar vortex” and the potential impact it can have on the upcoming season. But what exactly is the polar vortex and what does it mean for New Yorkers this winter?

Fortunately, Paul Pastelok, an AccuWeather Senior Meteorologist and Chief US Meteorologist, spoke with the Staten Island Advance/SILive.com and clarified the role the polar vortex could play in the winter of 2024-25. Where it is, the polar vortex may lead to an extended burst of arctic air across the US late in the season.

What is the polar vortex?

The polar vortex is a “constant feature” that begins to “appear” sometime in September and usually persists until April or May.

Pastelok said the polar vortex is an area of ​​low pressure in the upper atmosphere that rests over the polar region.

“The rotation is normally out of the counterclockwise direction because it’s a low pressure area,” Pastelok said. “And so when the polar vortex strengthens and becomes strong over the pole, typically what happens as a result of that is most of the cold is trapped and concentrated in the polar region.”

When that happens, those areas in the middle latitudes, including the U.S., generally experience a west-to-east airflow and typically cool, potentially mild temperatures, according to Pastelok.

A strong polar vortex bottles all that arctic air over the polar region, preventing any cold from escaping. However, meteorologists like Pastelok are monitoring the vortex to see if they can forecast any disruption, which could lead to some of that cold air leaking into the US.

Pastelok and colleagues in the meteorological field are monitoring to see if there are inflows of warm air entering the stratosphere (the layer above the troposphere, where we live) and impacting the circulation of the polar vortex.

When these inflows affect the polar jet stream, circulation is disrupted. Pastelok says “bumps” and “grooves” start to develop then, allowing cold air to escape from the polar region.

“First, it should descend to the lower levels, and then the air masses around it push it and move it around the globe,” Pastelok said.

If that leak occurs, the encroaching Arctic air could cause a disruptive pattern that persists for three to five weeks straight, he said.

“It’s not a short-term event where you have a cold front followed by a cold front for a few days,” Pastelok said.

Polar vortex forecast for winter 2024-25

As detailed in the latest AccuWeather winter forecastmuch of the nation, including NY, is bracing for a milder season. However, a potential disruption of the polar vortex could lead to a peak of cold air sometime in late winter.

While it’s very difficult to forecast a polar vortex disruption months in advance, Pastelok says examining conditions in past years gives an idea of ​​how likely the polar vortex is to affect U.S. weather.

“This year, the setup, when you look at the research, is not for frequent polar vortex disruptions,” Pastelok said. “It actually looks very strong in the middle of winter, like January, and we should expect less chance of the polar vortex having an influence or impact on our area.

Toward the end of winter, several large events in the past caused major disruptions, the research shows, and that would mean we could see a period of unstable weather in late winter, he said.

Despite this early outlook, Pastelok said the vortex may not necessarily affect North America; Any disruptions could end up hitting Europe or Asia. Finally, the weather systems in place at the time of the disturbance will direct Arctic air, preventing any specific forecast that far out.