Weather researchers are warning that a polar vortex could hit North America over the festive period, bringing heavy snow and freezing conditions to the U.S. and to Canada.
According to the Washington Post, experts believe there is a chance that the weather phenomenon — which usually sits over the Arctic Circle — could move south in the coming weeks. Such a weather pattern could presage a return of the extreme conditions that hit much of the United States in February and March of this year.
It was Judah Cohen, a climate expert at Atmospheric and Environmental Research, who first warned of the risk in a Twitter post. He said, “Confidence is growing in a significant polar vortex disruption in the coming weeks. This could be the single most important determinant of the weather this winter across the Northern Hemisphere.”
The polar vortex is like a river of wind which usually circles the North Pole. While it remains stable, weather in the northern hemisphere remains relatively normal. But if the vortex is disrupted, it can bring extreme weather conditions.
Earlier this year, temperatures then dropped well below zero in the northern states — with some places like North Dakota and Minnesota dropping below minus 30 degrees Celsius, and snow blanketing much of the country. Such conditions always cause widespread disruption, and can be dangerous for elderly or vulnerable individuals.
With the anticipated sudden stratospheric warming/disrupted #PolarVortex I discuss the three important stages of such events, the timing of temperature swings associated with each stage and when to believe the weather model forecasts in the updated blog. https://t.co/9ZWSlvqUI6 pic.twitter.com/Dp2CXiZaLa— Judah Cohen (@judah47) December 17, 2018
The suggestion that North America could be in for a serious cold spell will come as a shock to many. Back in October, U.S. meteorologists confidently predicted that there was a warm winter ahead — thanks to the development of a weak El Niño weather system.
These predictions now look less sure, but the vortex is unpredictable, and opinions are divided as to whether Cohen’s modeling is correct. Amy Butler, from the National Oceanic and Atmospheric Administration, tweeted that “not all other models on board yet so still reason to be cautious.”
All GEFS members now committing to a reversal of 60N 10mb winds #SSW between Dec 25-30 which is somewhat astonishing for a 9-14 day forecast. However not all other models on board yet so still reason to be cautious. pic.twitter.com/XrBCfggxJY— Amy H Butler (@DrAHButler) December 16, 2018
But Cohen followed up on his original post by warning that the polar vortex was likely to break up into three different vortices, commenting that “this could be very interesting.”
For now this is more for entertainment purposes than predicting our #weather but GFS predicting the #PolarVortex to split into three different vortices to start the new year, this could be very interesting. pic.twitter.com/X97c46MLQS— Judah Cohen (@judah47) December 18, 2018
He concluded by noting that climate models had suggested that there was an increased risk of snow on both the East Coast of North America and in Europe early in the New Year. He did, however, say that it was not yet clear whether this was related to the polar vortex phenomenon or not.
Weather is never a precise science, but if Cohen’s predictions are correct, it could be a long and cold winter for many North Americans.