Preparations are underway as an arctic blast dives into the nation's interior and southern regions and pushes a snowstorm into the Mid-Atlantic and Northeast that will be followed by lethal cold.

A potent shot of Arctic air starts settling in Monday as a massive dip in the jet stream pulls in frigid air across the entire eastern half of the country. Temperatures are set to drop as low as 20 degrees below average Tuesday and Wednesday with highs only reaching the teens, with lows in the single digits and even plunging below zero.

An arctic blast will send temperatures across the United States plummeting as bitterly cold air that originated in Siberia will arrive from Canada by week’s end, bringing with it dangerously cold wind chills for millions of Americans.

Snow and winds are likely to disrupt traffic, trigger flight cancellations, and cause headaches for people traveling to D.C. for Inauguration Day. Baby, it’s cold outside, and it’s about to get even colder for much of the United States.

Most of the U.S. will enjoy milder temperatures on Thursday, but the warmup will be brief as a polar vortex will send temperatures tumbling below freezing for most of the nation starting this weekend.