It’s really, really cold again – as the US shivers through at least the eighth blast of air from the Arctic this winter. Here’s why it keeps happening.

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 weeken

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,