A beautiful Tuesday in Chicago—but windy! The with was the product of an immense Canadian high pressure system with an eye-catching 1052 mb (31.03″) central pressure way up in Canada’s Nunavut territory. The sprawling high is in control of the surface wind field across virtually all of Canada and the northern U.S. The pressure gradient—which is to say, the change in air pressure across its southern flank is quite pronounced. Winds blow with gusto when that’s the case—and that was certainly the case in Chicago with winds gusts of 27 mph at O’Hare and 30 mph at Midway.
Those strong east/northeast winds will hold through the work week, coming right into the city of Lake Michigan—adding the the chill of the mid 30 ti low 40-deg temps forecast each day through the weekend.
Two snow systems are on our radar—the first Thursday night into Friday and possibly a second in the Sunday/Sunday night time frame.
A generous flow of moisture into the Thursday night/Friday system suggests the potential for sticking snow is real. While hardly a super storm, the combination of wind and snow in a winter with limited city snowfall could make for a messy situation later this week—one worthy of watching. Too early to attach numbers to it. The complexity of late season snow forecasts was on with the system late last week and we have several days to monitor developments and let this system get into the range of our higher resolution shorter term models.
Multi-model snow guidance out of the National Weather Service’s Weather Prediction Center puts the probability of measurable snow at greater than 40%–a fairly high assessment of snow probabilities at this distance in time.
The second system generates a range of model solutions lowering confidence in any one. So we’ll just flag it as one to monitor Sunday.
These may not be the last wintry systems we see. The pattern remains an active one through next week with a succession of weather systems indicated by modeling as likely to cross the Midwest.
There’s strong concurrence that BELOW NORMAL TEMPS are with us for a while—in fact over the next two weeks. That’s a big change from the overwhelmingly ABOVE NORMAL TEMP REGIME which has dominated the winter and early spring season to. While temps this week will sneak in at 2-deg above normal, next week’s predicted temp shortfall (compared to normal) will fall 5-deg below normal. And, on a day to day basis, every day from Thursday this week forward through next week and the following weekend is to come in BELOW NORMAL.
–Clocks go ahead an hour before heading to bed Sat night—as Daylight Saving Time returns.
Full forecast details at the WGN Weather Center
TUESDAY NIGHT: Clouding over, breezy and chilly—but still above normal. Low 35.
WEDNESDAY: Clouds break at times allowing some sunshine. Blustery from the east/northeast and chilly for the season. High 43—but upper 30s lakeshore.
WEDNESDAY NIGHT & THURSDAY: A good deal of cloudiness, continued breezy and cold. Low Wed night 35. High Thursday 39.
THURSDAY NIGHT & FRIDAY: Windy with wet snow developing. A wintry mix possible—especially south. Wind gusts topping 30 mph possible Friday making with a potentially messy weather situation. Low Thursday night 32. High Friday 35.
SATURDAY: Remaining mostly cloudy, chilly. Peeks of sun can’t be ruled out. High 37.
SUNDAY: Cloudy, chance of some snow or flurries. High 38.
MONDAY: Mostly cloudy, breezy and cold. Some flurries possible. High 36.
TUESDAY: Sunshine’s back—but cold and breezy. High 34.