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 weekend.

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