Modeling suggests rain overspread to city and close-in suburbs in the 7 to10pm Monday time and won’t wind down until 3 to 5pm Tuesday. That’s a 17 to 20 hour spell rainy period which may produce soaking rains of 0.60″ to 1.30″ range across the metro area. Rain is needed here. November to date (i.e. Nov 1-19) has seen just 0.10″ of rain at O’Hare going into this system, which is just 6% normal. Rainfall in the predicted range would amount to the heaviest rain here since 1.48″ fell which last fell in Chicago over a 5-day period from this past Oct 11-15.

Gusty NE overnight and Tuesday morning winds will shift NW Tuesday afternoon with top velocities of 24-28 mph likely—even a higher over Lake Michigan—are likely to churn the waters there with waves frequently elevated in a week of gusty winds. Waves are likely into Tuesday from 3 to 8 feet.

The Chicago area has moved into a decidedly colder weather regime with temps this week likely to come in close to 9-deg colder than last—meaning daytimes highs in the 40s will be the mainstay. Even chillier weather takes hold next week with temps predicted to come in more than 4-deg colder and to average 3-deg below normal. These colder temps will chip away at a November surplus of nearly 5-degrees.

Chicago’s is headed for is heaviest round of precip in the form of cold, wind-driven rain—in more than a month.

Despite the coming temp downturn, November, 2023’s opening 20 days are averaging more than 3-deg milder than a year ago. Precipitation is out of the picture for Chicago the remainder of the work week, though some lake effect snow and rain showers are to fall on the other side of the lake. Several models hint at a weather system which would arrived in an atmosphere cold enough to support some snow this weekend in parts of the area. We’ll be monitoring this. It’s not yet a slam/dunk—but interesting to keep an eye on.

Frank Wachowski reminds us 4.2″ of snow fell on this date (Nov 20) 8 years ago in 2015—and that another 7″ of snow came down the following day—Nov 21, 2015. That’s not typical—but it sure shows what can happen as we continue to move deeper into cold season.