CHICAGO — The first measurable snow in more than seven months fell in the Chicago area early Tuesday, dropping 0.8″ at Midway, 0.7″ at O’Hare and as much as 3.5″ in parts of northwest Illinois.
The snow has long since exited the area, but Tuesday’s rain will continue through tomorrow and move out of the area Wednesday night. Rainfall estimates put most storm precipitation tallies across the Chicago area in the 0.30″-1.20″ range.
Overcast skies will carry over into Thanksgiving Day, although some clearing appears to be a reasonable bet Thursday afternoon.
What stands out most in modeling looking into next week is a decided change to a colder weather regime.
The Sunday through Saturday period next week is scheduled to average 31 degrees, a full 10 degrees colder than this week. It looks to be the most prolonged chilly period we’ve seen here in some time, potentially since last February.
Driving the cool down is a huge warm pool of air predicted to take shape over western North America. Such a feature is likely to produce ridging aloft there which, in turn, sets up a north/northwest upper steering flow into the Chicago and the Midwest.
What is hardly carved in stone at this point, but will be watched is the prediction of a strong push of chilly “NNW” winds into the Midwest. The air in such a cold push would be quite unstable and might well support snow showers or flurries over a multi-day period including Monday and Tuesday.