After an unseasonably warm November, the U.S. is in for the first arctic blast of the season.
The cold air has already reached many of the western states and will begin to invade the Lower 48 states, according to Weather.com.
Several meteorologists have noted on Twitter that the weather models for this system are reminiscent of the infamous polar vortex of 2014.
According to the National Weather Service, a polar is "a large area of low pressure and cold air surrounding both of the Earth’s poles." It also notes that they always exist near the poles, but strengthen in the winter months.
The National Weather Service notes that when the polar vortex expand and send cold air south with the jet stream, areas of the United States are hit with Arctic air. So, the polar vortex of January 2014 wasn't anything new -- in fact, the National Weather Service's website says that it was similar to other cold outbreaks in 1977, 1982, 1985 and 1989.
So what does it mean for us?
Mashable reports it could mean temperatures could fall well below average for this time of year.