Severe winter weather has been linked to warming in the Arctic.
After the weather we've seen so far in March, it may come as no surprise that a new study says extreme cold and snow are becoming more common in the Northeast.
"The weather is schizophrenic in a way," described Dr. Judah Cohen, director of seasonal forecasting at Atmospheric and Environmental Research, based in Lexington, Massachusetts.
His new study, released just this week, proves what many suspected.
"Winter starts later, and ends later," he said. "2015 would be the poster child for that -- up to Jan. 22, absolutely nothing went on, then all the sudden..."
Studying data back to 1950, Cohen found that our winter season is not only shifting, but it's becoming more extreme.
"A 14- [or] 16-inch snowfall happened every four years, you know. Now it's happening, like, every two," Cohen said, citing the data in the recently-released paper.
Cohen's study links that more extreme late season cold and snow to a warming Arctic.
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"When the Arctic is warm, that does favor colder temperatures," he said of weather in the Northeast.
According to Cohen, warm air increasingly pools north of Scandinavia, near the surface, early in the season.
Over the course of winter, that warm air works higher into the sky, weakening the polar vortex.
Normally, the vortex keeps cold air locked near the poles. When it weakens, cold can spill south.
"The fact that there's kind of this bullseye of warmth right over there, that just kind of happens to set up a wave pattern, the atmosphere that's most favorable for this polar vortex disruption," Cohen said.
The big question — as the Arctic continues to warm in the future, will winters get more and more extreme, or is there a tipping point?
"It's hard to know," Cohen said. "what's happened up to now has been a surprise to the climate community."
He is optimistic, however, that better understanding the relationship between a warm Arctic and a cold Eastern United States can help improve seasonal forecasts. Those forecasts are of high value when predicting things like energy demand and usage.
