Whether you call it a polar vortex, Arctic blast or February freeze, one thing is for sure — it's going to be bitterly cold across the eastern half of the country this holiday weekend. Through ...

Most of the U.S. will enjoy milder temperatures on Thursday, but the warmup will be brief as a polar vortex will send temperatures tumbling below freezing for most of the nation starting this weekend.

The polar vortex, a rotating bubble of cold air around the North Pole, is about to break off and head into much of the United States for the second half of January.