From a story on axios.com by Andrew Freedman headlined “Arctic blast takes aim at U.S. for Christmas, New Years”:

A blast of Arctic air straight from Siberia is poised to spread across the continental U.S. around Christmas, shattering records and potentially spinning up major storms.

Why it matters: Meteorologists tell Axios this may be the most extreme cold air mass to affect the U.S. during December in many years, with computer model data showing temperatures running 30 degrees below average by Dec. 23.