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.

We start the following work week with a polar vortex. This will bring in unseasonably cold air to the region and wind chill temperatures back to the negatives. But what is a polar vortex? The polar vortex is the jet stream above the Arctic Circle.

People living "basically anywhere from the Rockies eastward" will see extremely cold temperatures over the next several days, a meteorologist says.

Temperatures are expected to plummet over the weekend, bringing life-threatening conditions to large stretches of the United States. The polar vortex will send temperatures below freezing for much of the country starting this weekend and stretching into next week,

The polar vortex is a large area of low pressure, winds, and cold air surrounding both of the Earth’s poles, according to the National Weather Service. The term “vortex” refers to the circulation of air that helps keep the colder air near the Poles. This vortex has always existed and is not something new.

Abnormal weather events and severe winter storms could be caused by a disrupted polar vortex. Find out here how the polar vortex affects the weather.

A series of cold fronts the last few weeks has kept Florida downright chilly, as another winter storm starts to take aim this weekend

It's going to get cold in Tennessee. Meteorologists predict freezing temperatures for much of the state. Here's the latest.

The polar vortex is expected to reach the Utah-Idaho border sometime in the late afternoon and evening Friday as it continues to move south. As it moves through parts of the state, it will produce small snow showers, bringing more snow to the region before drier conditions return.

The colder-than-normal temperatures in Houston are part of a larger pattern of Arctic air sweeping through Texas and much of the southern United States.

Here is what is and isn't a polar vortex when Colorado receives cold like what is forecast for the holiday weekend.