The back-door COLD FRONT’S PASSED and now strong, post-frontal full fetch north/northeast winds have taken hold and are sweeping off Lake Michigan over Chicago’s shoreline. Little wonder the winds are strong–with gusts from 30 to 40 mph being reported up and down the western Lake Michigan shoreline.
Wednesday morning surface weather map showing a well developed 1037 mb (30.62″) high pressure centered over Ontario province in southern Canada. The winds beneath its southern flank are strong. 
Here’s a windy.com depiction of the “full fetch” NNE winds blowing down the length of Lake Michigan. The reference to “full fetch” winds means winds are blowing southward the length of Lake Michigan. That’s important because this offers the wind time to transfer its kinetic energy to the lake surface building waves. It’s no accident the highest waves to sweep onto Chicago beaches occur in “full fetch” wind set ups like Wednesday’s. 
Here’s a snapshot of wind and wind gust reports at 9am CDT Wednesday. Wind gusts of 30 to 40 mph are being reported up and down the western and southern shoreline of Lake Michigan. Little wonder wave heights have increased quite dramatically. 
Here’s a model forecast off the Weather Service’s 3km HRRR showing the the full fetch winds blowing the length of Lake Michigan. Colors on this depiction indicate wind velocities. The GREEN AND YELLOW shaded areas are the regions with the strongest winds. 
A GOES EAST true color weather satellite image mid-Wed morning showing the stratus deck we’re observing blowing southward on the Chicago shoreline. Satellite imagery is courtesy of the COD GOES satellite website. 
Surface wind streamlines, which show the orientation of the winds blowing Wednesday morning are superimposed over the GOES EAST true color weather satellite image.
THE RAIN SITUATION REMAINS dismal. May is headed for a close as Chicago’s second driest on the books and there appears little prospect for organized rainfall for the foreseeable future—which means into next week. There WILL BE AN INCREASE IN MOISTURE LEVELS from Wednesday forward next week and that’s when scattered t-storms may “bubble up” across the area.
Daytime highs away from Lake Michigan could be at or above 80 by Saturday afternoon—just in time for the Memorial Day weekend. The warming is to add a few degrees to Chicago area high temps each day from Friday through mid next week when there are growing indications 90-deg temps look to be a good bet. An examination of Chicago high temps since 1942 show that 53% of those 81 years have produced a 90-degree temp by June 3—which appears to be what’s on tap this year.
The air is dry—dew points and relatively humidities are low and expected to remain that through the Memorial Day weekend so temps will cool at night and warm vigorously during the day. LAKE BREEZES—in other words, easterly winds off Lake Michigan—are to be a daily occurrence into next week, so daytime highs will be cooler along Lake Michigan each day. But with a much lighter wind regime taking shape, the inland penetration of cool air will be limited. And even on area beaches, daytime highs in the 70s by Sunday and Monday should make for some wonderful holiday weekend beach weather.
But lake temps are STILL VERY COOL. So hypothermia remains a risk and care should be taken swimming in the chilly water despite warm air temps.
