Most of the country is preparing for the return of the polar vortex a few weeks removed from the last one which covered most of the country in sub-freezing temperatures.
There has been a great deal of talk regarding the polar vortex, but few seem to have a solid grasp on what causes it or what it is other than artic cold.
By definition the polar vortex is a "large-scale cyclonic circulation in the middle and upper troposphere centered generally in the Polar Regions."
The polar vortex, as its name indicates, is comprised of circular winds located at both poles. Normally during the winter months the winds maintain a tightly circulating air mass. However, when those winds weaken and begin to move south away from the polar region they are picked up by the jet stream, which takes it farther south than normal.
There are no know causes for the polar vortex but some scientists have stated that warming temperatures in the artic may play a role in disrupting the arctic air mass.
Forecasters have issued a warning about the polar vortex which is expected to last until the end of January.
"The high amplitude pattern is forecast to get more extreme. The polar vortex will move farther south and get stronger. The pattern will gradually change the current mixture of Pacific and Arctic air in the Canada Prairies and the North Central U.S. to all Arctic air. The air will get significantly colder over the Canada Prairies and the much of the eastern half of the nation as a result," according to a warning issued by Accuweather.com.
The blast of cold air comes at the same time that a weather system in moving east and will bring up to a foot of snow across the Northeast and Mid-Atlantic regions on Tuesday.