What is a polar vortex? Chicago is on target to see brutal cold for the next few days.
CHICAGO (CBS) — A chunk of the polar vortex is coming to the Chicago area this week, bringing the coldest temperatures of the season with dangerous wind chills.
The polar vortex is an ever-present, large area of low-pressure and frigid air surrounding the Earth's poles. While it exists in both the summer and winter, it is colder and more expansive during the winter months.
The term "vortex" refers to the counter-clockwise flow of air surrounding the frigid air – the bounds of which act like a belt, containing the coldest air near the Poles.
Sometimes during the northern hemisphere winter months, that belt near the North Pole can get a bit wavier and extend southward toward the U.S.
When a chunk of the polar vortex dislodges from the North Pole, it can bring Chicago's coldest periods of weather on record, such as those recorded during the winters of 1977, 1989 and 2014.
Arctic outbreaks associated with the polar vortex are not confined to the U.S. Portions of Europe and Asia also experience extreme cold periods connected to poles.
This week's coldest air blows in Wednesday afternoon and lingers through Thursday night.
Air temperatures locally will drop to the single-digits Wednesday night with wind chills of 10 to 20 degrees below zero. These will be dangerous to anyone with exposed skin who is outdoors for an extended period.
Chicago warming centers are open
More than 300 public facilities that serve as warm indoor spaces are also available during cold weather. A map of all of the available locations can be found here.
Chicago residents can sign up for NotifyChicago alerts here. Text messages and e-mail alerts are sent out for incidents like severe weather.
The following warming centers are available:
Englewood Community Service Center
1140 West 79th St.
312-747-0200
Garfield Community Service Center
10 South Kedzie Ave.
312-746-5400
Martin Luther King Community Service Center
4314 South Cottage Grove
312-747-2300
North Area Community Service Center
845 West Wilson Ave.
312-744-2580
South Chicago Community Service Center
8650 South Commercial Ave.
312-747-0500
Trina Davila Community Service Center
4312 West North Ave.
312-744-2014
City officials recommend calling 311 to request a shelter placement, to request a well-being check for seniors, or to report issues with heat in residential buildings.
Warming center hours may be extended depending on extreme conditions. CBS News Chicago meteorologists will continue to monitor forecasts and provide updates.
