Chicago is seeing its fourth straight month dominated by below-normal cold, a pattern that seems locked into place at least through next week.
Temperatures dipped below zero in some western suburbs starting Wednesday night, with wind chills ranging from minus 12 to minus 24. And there’s little prospect that wind chills will creep above zero until sometime Saturday, when yet more snow may hit.
It’s possible several inches of snow may fall ahead of still another slug of arctic air expected to ride into Chicago Sunday into early next week.
The extent of this latest cold blast across a wide area of the Lower 48 is stunning, with the arctic air mass carrying sub-freezing temperatures south to the Gulf of Mexico. Advisories for dangerous wind chills were issued overnight across 21 states.
Nothing encourages the spread and expansion of bitterly cold air than a fresh cover of snow — like the one that covered a large swath of the country Thursday.
Chicago was walloped by its third heaviest snowstorm of the season late Tuesday into Wednesday morning. The storm dumped anywhere from 2.6 inches to as much as 9 inches. That accumulation was part of a storm system responsible for radically increasing the Lower 48’s snow cover.
The National Oceanic and Atmospheric Administration reported Wednesday that 63.6 percent of the country boasted a snow-pack, the season’s greatest snow cover in more than a month. Chicago has gotten 59.6 inches of snow so far this season, more than six times last year’s 9.2 inches and nearly three times normal. For snow seasons through Feb. 5, this winter is now in third place behind only 1978-79 and 1977-78. And even though there are several more weeks in which snow could be expected to fall, this season has made it to eighth for overall snowfall in Chicago history.
It’s little wonder cold air is on the move again.
But seasonal changes — including longer days, a higher angle of the sun and an 82 percent increase in solar energy — are slowly chipping away at the intensity of the daytime chill.