If you live anywhere within the northern two-thirds of the United States, you’ve probably noticed that it’s pretty chilly outside. The plunge in temperatures over the past few days comes courtesy of an invasion of Arctic air that has been captured in a mesmerizing new animation from the National Oceanic and Atmospheric Administration.

The animation, made with weather data from the NOAA/NCEP Real-Time Mesoscale Analysis, begins on Saturday (Jan. 19) with very cold air seen only over the Rockies, Montana, North Dakota, the northern half of Minnesota and the northern portions of New England. Much of the eastern and central parts of the country saw weekend weather that was balmier than usual for mid-January.

Thanks to a kink in the jet stream that brought it dipping down, the cold air begins plunging southward on Sunday, mostly in the northern plains states and the Midwest. On Monday it begins to surge even farther to the south, covering the Plains, the Midwest, the Northeast and even extending into some of the southern states.

Source: Yahoo! News – Chilling! Arctic Air Invasion Captured in Animation