The bitter cold temperatures and wind chills Thursday night into Friday are the result of a disruption in the polar vortex, according the National Oceanic and Atmospheric Administration.
The polar vortex is located in the stratosphere about 30 miles above the Earth. A sudden stratospheric warming broke the polar vortex on November 28. At the same time, a large high pressure ridge over Alaska is driving Arctic air down into northern states including Maine.
Dr. Amy Butler, Research Scientist for NOAA Chemical Sciences Laboratory, said we're likely to see bigger impacts from the polar vortex disruption in the next week or two.
"The polar vortex is always there every winter. It's really when the polar vortex is disrupted or sort of disappears, as just happened, that we actually see these big impacts from these cold air outbreaks," Butler said.
November's unusual early polar vortex event, Butler said, is just one of three ever recorded dating back to 1958. The last one was in 1968. She said the polar vortex normally peaks at the end of December or early January, and scientists are trying to understand if there will be more of them.
Butler said people often think the polar vortex is coming but what they're referring to is the cold air that's due to the polar vortex disruption.
Wind chills Thursday night will range from 8 degrees below in southern Maine to 25 degrees below in northern Maine, according to the National Weather Service in Gray. Meteorologist Zack Hargrove says weekend temperatures will rebound before another cold front arrives on Sunday.
More information on sudden stratospheric warming and polar vortex disruption.
