Feeling a chill? The unstable polar vortex is back, and it’s ready to deliver a brutal winter to the East Coast of the U.S., at least for the next several weeks – and maybe longer.
“[It] can affect the entire winter,” Dr. Judah Cohen told the Washington Post in an interview.
Cohen, a climate researcher at Atmospheric and Environmental Research, has been monitoring conditions in the Arctic, and says we’re in for another unstable polar vortex this winter.
A weaker polar vortex spells icy conditions and a brutal winter outside the Arctic. The polar vortex is a swirling mass of cold air centered, as the name indicates, near the North Pole. When it’s spinning tightly, that cold air stays massed in the Arctic.
But as the vortex loses stability, that cold air spills south, stretching freezing fingers of winter down farther south than usual.
The unstable polar vortex made itself felt last year, in February. Before then, Europe and Asia had seen a normal winter – cold, but nothing unusual.
Then, scientists say, the vortex was disrupted. The result? The “Beast from the East,” a frigid, sudden and brutal winter that swept from Siberia into the rest of the Eurasian continent. In March, another finger stretched down from the unstable polar vortex into the United States, hurling a series of nor’easters at the East Coast.
“We were still feeling the impacts into the end of April,” Cohen told the Post.
An unstable polar vortex led to brutal winter conditions in 2009-10 and 2013-14, too. The cause of the instability and the freezing temperatures that follow is usually, ironically, warming in the stratosphere, according to experts.
Current models by Cohen and his colleagues point to a burst of cold on the East Coast as we enter January, and in Europe toward the middle of the month, though conditions could change. Predicting the vortex is still a new and inexact science.
Still, people living in those areas should brace for freezing weather.
“Confidence is growing in a significant #PolarVortex disruption in the coming weeks,” he tweeted. “This could be the single most important determinant of the weather this #winter across the Northern Hemisphere.”
Read more about Cohen’s predictions at the AER blog.