Not since 1965 has the first day of spring been so cold in Chicago.
The official high on Wednesday was 25 degrees, the chilliest peak daytime reading here in a month. The reading was 23 degrees below the normal for March 20 and 60 degrees colder than the high of 85 a year ago. In fact, the first 20 days of March were 23.7 degrees behind the same period a year ago.
The unseasonable chill is being driven by the so-called Greenland block: A vast reservoir of warmer than normal air stretching from northern Russia across the North Pole and into northeast Canada and pushing Arctic air into the Lower 48.
That flood of frigid air is being fostered by a snowpack that covers twice the real estate it did at this time last year, running from the Rockies across the northern Plains and Upper Midwest.
So as Chicagoans and fellow Midwesterners shiver through abnormally low temperatures, coastal areas of Baffin Island and Labrador province in northeastern Canada, as well as on much of Greenland’s coastline, are experiencing warmer weather.
The Greenland block is expected to affect our weather in the closing weeks of March and into early April.
Meanwhile, the latest storm to churn off the Pacific Ocean could impact the Midwest this weekend. A range of model forecasts puts the storm on a track from Texas into the Ohio Valley Saturday night into Sunday. Varied barometric pressures between that system and a huge Canadian high to the north are to set up a broad area of vigorous northeast winds.
Given the cold air predicted to hold here into next week, this could set the stage for lake snow showers and flurries.
The track currently generated by a number of computer forecast models places the system’s heaviest snowfall to Chicago’s south. But the Chicago area is close to the storm’s “action zone” and developments will have to be monitored in coming days.
A more northerly track could unleash significant snow on Chicago, though by no means is that a sure thing.