Scott Olson / Getty Images file
Chicago commuters wait for the train in sub-zero temperatures on Jan. 7.
Temperatures are set to drop again in the Midwest and Northeast starting Sunday, a forecast that already is prompting the return of the phrase “polar vortex” -- widely used to describe the blast of cold air that chilled the U.S. earlier this month. But while the Upper Midwest, Great Lakes and the interior Northeast will experience below-average temperatures in the coming week, don't call it a “polar vortex,” meteorologists say.
The "polar vortex" is a real weather phenomenon, just not one that actually visits the United States, they say. It's actually a circular weather pattern that has always been stationed above the Arctic, explains weather.com.
According to the National Oceanic and Atmospheric Administration (NOAA), the swirling high-altitude system never moves into the U.S., though parts of it can "break off" and push cold air south.
When the Arctic is warmer, the U.S. gets cold
The cold experienced in early January was actually a result of the polar vortex weakening, becoming warmer and therefore releasing its powerful chill beyond its normal reach through the northern climes, NOAA says.
Weather experts at NOAA said the intense cold air the U.S. has experienced is in fact a result of a warming world and increasing climate variability. While researchers cannot yet determine whether the fluctuations are a result of natural patterns or environmental effects, meteorologists can predict that parts of the U.S. will see freezing weather again in the coming days as a result of a polar vortex breakdown.
The first stops for the next wave of cold air are the Upper Midwest and Great Lakes region on Sunday, according to Weather.com. The Northern Plains to the Upper Mississippi Valley, Great Lakes, Ohio Valley and Northeast will get hit by the blast on Tuesday into Thursday.
Temperatures will hover in the single digits and teens in these areas, which are 10 to 25 degrees below average for this already-chilly time of year.
Parts of the Upper Midwest can expect temperatures in the negative teens, according to Weather.com. The northern-most states of the Northeast could also experience overnight temperatures in the negatives on Tuesday, Wednesday and Thursday.
Temperatures in the South will also be below average, but only by 5 to 15 degrees, Weather.com forecast. The Carolinas and Georgia can still expect highs in the 40s.
Meteorologists assured that late January’s cold outbreak will not be as unbearable as the one earlier in the month.
For example, while lows in Chicago were in the negative teens in past weeks, temperatures may not even dip below zero in the coming days.
Wind chills will also not be as cold as they were in the first days of the new year, Weather.com said.
The bottom line: For those who made it through the first polar vortex temperature tantrum, this one will be a walk in the park. (But if you're going for a walk in the park, be sure to bundle up!)