Polar Vortex Is Back: Coldest of the Cold En Route to U.S.

http://www.climatecentral.org/news/polar-vortex-is-back-coldest-of-cold-en-route-to-us-17003
The polar vortex is back, and for many suffering through an already frigid winter, the Arctic air barreling into the lower 48 states may be the coldest of the cold yet.