A lobe of the polar vortex, a ring of freezing air typically found near the North Pole, will once again move into the central and eastern states this week, bringing some of the coldest air of the winter season so far — and even helping fuel yet another winter storm in coming days.

The latest arctic blast will move into the northern Rockies and northern Plains Saturday and spread to the central and eastern U.S. through much of next week.

Harsh weather moved west as a polar vortex was expected to grip the Rockies and the northern Plains after winter storms pummeled the eastern U.S. over the weekend.