Meteorologists warn that the coldest burst of Arctic air this season is coming to put an icy and prolonged exclamation point on America’s winter of repeated polar vortex invasions starting this weekend.

A week-long, unusually cold Arctic outbreak will bring frigid conditions to most locations east of the Rockies starting today. For some locations, this could be the coldest air so far this season. Why it matters: This event is likely to be more intense than the two previous polar vortex-related cold snaps in the U.

An Arctic blast tied in part to the polar vortex is driving record frigid air south from the Northern Plains toward the Gulf Coast Tuesday in a cold snap that will last the entire week. Threat level: This event is forecast to set records for the coldest temperatures on record for this late in the season,