June opened with Chicago’s 4^th 90-deg or higher temp of 2023.  The afternoon featured a large lakeshore to inland temp spread thanks to a 7^th consecutive day of lake breezes—but shoreline temps weren’t quite as cool as in recent days.  At mid-afternoon, temps ranged from a high of 95 at Warrenville, Tinley Park and Carpentersville; 94 at Glen Ellyn and 93 at Hawthorn Woods, Batavia and Oswego—–to 67 just offshore at the Wilmette Harbor buoy and 72 on the shoreline at Lake Forest.

Observers scanning the skies in Chicago have watched towering distance cumulonimbus clouds (i.e. “thunderheads” in the distance over sections of Michigan and northwest Indiana—and to the south and west of Chicago.  But storm coverage wasn’t as extensive as yesterday when COCRAHS volunteer observers reported as much as 1.78″ with t-storms near Yorkville and 1.48″ just west of Monee.  Impressive as those totals were, their areal coverage was limited and May closed last night at O’Hare with a paltry 16% of its normal precip—only 0.71″ for the entire month—enough to quality the 4^th driest of the past 153 Mays.  

The 3 month METEOROLOGICAL SPRING season (March, April & May) also closed at midnight last night and finished with just 61% of its normal rain—a little over 6″ in a period which should have seen well over 10″ of rain. The spring season ranked among the 17% driest here since the early 1870s and among the 11% warmest.

Coming days see rain chances evaporate as marginally better organized east winds bring modestly drier air into the area. The east winds come with lake cooling into shoreline airlines which further stabilizes the air mass and erodes rain chances.

Temps remain warm—we expect another 90-deg temp Friday inland—but highs which fall back to the 80s inland over the weekend. And model estimates of potential Chicago rainfall through mid month currently come in 25% normal.

High pressure from Canada drops into the area Tuesday and Wednesday next week with noticeably cooler and better organized FULL FETCH “NNE” winds running the length of Lake Michigan into Chicago.  This tends to produce the most pronounced cooling this time of year.  BUT that strong NNE flow breaks down later next week, the weekend which follows and into the following week and this is likely to allow temps to warm again—and noticeably.

THURSDAY NIGHT: Chance of an isolated t-storm early, mainly well south and west of the city—the scattered clouds, warm and moderately humid with diminishing winds and periods of calm.  low 67.

FRIDAY: Mostly sunny and quite warm—borderline hot again inland with moderate humidities.  Cooling lake breezes on area beaches. High 91 inland—but upper 60s to mid 70s along Lake Michigan.

FRIDAY NIGHT: Scattered clouds, warm. Low 65.

SATURDAY AND SUNDAY: Sunshine and warm with scattered fair weather clouds, mainly inland. Cooling northeast winds along Lake Michigan. High Saturday 85; Sunday’s high 87—with beach highs ranging from the mid 60s to low 70s.

MONDAY: Sunshine gives way to more clouds, warm. Chance of some late day and possible nighttime showers. High 87—but turning noticeably cooler with the arrival of northeast winds along Lake Michigan in the afternoon and at night.

TUESDAY & WEDNESDAY: A good deal of sunshine emerges, breezy and noticeably cooler with gusty “NNE” winds. Highs both days 74—but mid 50s to low 60s beaches.

THURSDAY: Generous sunshine and lighter, more localized shoreline NE winds allowing temps to begin warming. High 83—but mid to upper 60s lakeshore.