The Polar Vortex in the upper atmosphere has disintegrated after the intense warming of the stratosphere in mid-March.

It will feel like winter for many across the Midwest and Northeast at the start of the week as Arctic air surges south from Canada. Temperatures across much of the Midwest and ...

as an Arctic air mass spilled south and eastward across the U.S. Sunday morning saw temperatures as low as minus 20 degrees Fahrenheit to minus 40 F in northern and northeast Montana. Saco ...

Early this week, a major cold event will be produced due to its powerful lobe throughout the Northeast and Great Lakes. The Polar Vortex's collapse will cause a major Arctic blast from central ...