polar vortex

[ poh-ler vawr-teks ]
/ ˈpoʊ lər ˈvɔr tɛks /

noun

a whirling mass of very cold air that sits over the North or South Pole: A displaced polar vortex is causing Arctic temperatures across the United States.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019