Guess what? It’s still cold outside.
Temperatures that plunged into the single digits Monday evening stayed there Tuesday morning, while the area remained under a wind chill advisory until 10 a.m., according to the National Weather Service.
The biting cold is the product of a frigid air mass, the coldest the region has seen in two years, descending over the area. That means temperatures will be mostly in the single digits until Wednesday, the weather service said.
At O’Hare Airport the recorded temperature at 6 a.m. Tuesday was a frigid 1 degree, but that dropped to about minus 13 once the wind chill is factored in, according to the weather service.
Richard Castro, meteorologist at the weather service’s office in Romeoville, said we’d be looking at a low of around minus 20 if the region had snow on the ground.
“This is actually quite an impressive mass of cold air,” he said. Within the system, temperatures aloft are actually colder than those in the last subzero front that visited Chicago in February 2011.
Castro said the earlier system produced a minus 9 reading at O’Hare Airport on Feb. 10, 2011, the last below-zero reading for the region. It occurred just after that winter’s “Snowmageddon” with about 20 inches on the ground.
Lack of snow acts as insulation. Castro said that if the incoming weather produces below-zero temperatures, it will mark a rarity for Chicago.
A weather service study of the period from 1960 to 2010 found only 16 days with no snow cover and temperatures in the negative range, Castro said.
The weather service expects temperatures to slowly moderate later in the week, with a chance of snow Thursday. Depending on the track of that storm, it could break Chicago’s ongoing record for most days without at least an inch of snow, Castro said.
As of Tuesday, the Chicago area has recorded 333 days without a snowfall of at least an inch and 331 days without a snow depth of at least an inch, he said. Both streaks broke records set in 1940, Castro added.
--Sun-Times Media Wire, Sun-Times
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