Don't let the incoming string of relatively warm days in the greater Philadelphia region fool you; the polar vortex is still around.

Another Arctic blast is on the move toward the U.S., bringing the potential for bitter cold and heavy snow accumulations to Michigan — possibly beginning during the holiday weekend into early December ...

Bitingly cold Arctic air keeps pummeling the U.S. with ruthless cold snaps—despite warming winters nationwide. A study explains why: the solution lies far above your head, in the upper atmosphere ...

When the polar vortex stumbles, the weather at ground level can pivot from mild to brutal in a matter of days. A circulation ...

An Arctic blast is expected to bring below-average temperatures to the central U.S. and New England in late November and early December. A weakening polar vortex, influenced by a rare weather ...