Temperatures will be a little colder this weekend, but dangerously cold temperatures are expected to return to Pennsylvania next week thanks to a polar vortex.
“The polar vortex is expected to become displaced from the Arctic Circle and plunge down to near the upper Great Lakes,” AccuWeather reports. “That will occur in the wake of the winter storm that may lay a swath of disruptive snow from the Midwest, Chicago included, to a part of the Northeast early next week.”
A polar vortex is a large pocket of very cold air, typically the coldest air in the Northern Hemisphere, which sits over the polar region during the winter season, according to AccuWeather. Dave Samuhel, an AccuWeather meteorologist, said that vortex is expected to move southward as it is pushed by warmer air near the North Pole.
AccuWeather anticipates temperatures will be 10 to 20 degrees below normal across the eastern half of the state, and 20 to 40 degrees below average in the western half.
"Highs may reach only the single digits and teens from St. Louis to Indianapolis and Pittsburgh, according to the report. Wind chills could make it feel even colder.