The United States is about 5 days away from a polar vortex descending down from the arctic. Air temps will drop deep into the negative range from the mid-west to the east coast.
A Polar vortex starts on the ground, and goes all the way up high into the stratosphere, reaching above 50km altitude. In the stratosphere, the polar vortex is usually just one large area of cyclonic circulation.
Frigid cold arctic air will move down into the United States with air temperature dropping to -13°F and as low as -22°F in some locations! Up in Canada, temperatures will be even lower. This is an unusually strong cold air outbreak for early December.
We will be keeping a close eye on this polar vortex and will keep you updated on any important further development.