The polar vortex appears to be on the move. That's because stratospheric warming is occurring at high altitudes above the North Pole, resulting in a spike in temperatures. That, in turn, could result in bitter cold air pushing southward into the United States within a couple of weeks, though where exactly that Arctic air will swoop down - and for how long - remains uncertain. LIVE UPDATES: How the polar vortex works.(CNN) The polar vortex is simply a low pressure system that swirls cold air around the polar regions of the globe. But the system can sometimes move off the North Pole.