textproduct: Chicago

KEY MESSAGES

- A heightened risk for rip currents will exist at southern Lake Michigan beaches through tonight.

- Near to below normal temperatures will persist through the week with additional shower and storm chances returning in the mid- to late-week time frame.

DISCUSSION

Issued at 215 AM CDT Mon Jun 22 2026

Through Tuesday:

The back edge of the rain shield associated with yesterday's storm system will continue to gradually peel away to the east over the next few hours, with our forecast area likely to be devoid of any precipitation by mid-morning. This afternoon, clearing skies will allow for air temperatures warm into the 70s away from the shadow of Lake Michigan, where persistent onshore flow will keep temperatures stuck in the 60s.

A few hi-res models indicate that a few showers or sprinkles may try to develop during peak heating this afternoon, primarily near the I-39 corridor, where temperatures will be warmest and some surface convergence/confluence is evident in modeled wind fields. Confidence in diurnal cumulus growing deep enough to support precipitation during the mid-afternoon and early evening today isn't particularly high given the absence of any real large-scale forcing support and that the saturated unstable layer depicted in hi-res model forecast soundings is somewhat shallow and capped by a warm nose at the 700 mb level. However, there appears to be just enough of a QPF signal to warrant the introduction of some low-end slight chance PoPs over a portion of interior northern Illinois during the late afternoon and early evening for some potential isolated spits of rain. Regardless, the vast majority of our forecast area will remain dry today once the last of the overnight shower activity clears the area.

Winds over Lake Michigan have been slow to come up and have, thus far, remained a bit lower than previously forecasted. The wave response in our nearshore waters has been more subdued as a result, but the latest buoy observations still indicate that waves are steadily building to levels that will create a heightened risk of rip currents at area beaches today. Winds and waves will then subside tonight into Tuesday as a surface high pressure center approaches the area and eventually passes right over us or very close by. Dry conditions are thus expected during the daytime on Tuesday, while daytime temperature readings will be quite similar to what they will be today.

Tuesday night through Sunday:

Late Tuesday night into Wednesday, global ensemble and deterministic guidance remains in good agreement that an upper- level trough will slide into the Upper Midwest, likely accompanied by a low pressure system at the surface. Moisture profiles should be plenty adequate to support rain showers across the region as this system passes by, and while lapse rates look to be lackluster on the whole, deterministic GFS and ECMWF soundings both depict CAPE profiles with equilibrium levels solidly above -20C that should be favorable for thunderstorms to occur in the area as well. The greatest coverage of showers and storms on Wednesday is favored to remain to our north in closer proximity to the upper trough, but the latest NBM PoPs still feature likely PoPs across the northern third of our CWA and mid-range to upper-end chance PoPs across the remainder of our CWA, and this looks reasonable for now based on the latest ensemble QPF distribution.

Ensemble consistency breaks down over the latter half of the week into the weekend, but still broadly suggests that a few follow-up shortwave troughs could traverse the region in the days following Wednesday. Thus, additional showery and perhaps stormy periods could be seen going into the weekend, but confidence in precisely when and where additional precipitation may occur during the latter half of the week remains low at this time. Confidence is higher in near to below normal temperatures persisting through the entirety of this week, though ensemble guidance does suggest that some warmer temperatures are on the horizon for the beginning of the following week.

Ogorek

AVIATION /12Z TAFS THROUGH 18Z TUESDAY/

Issued at 602 AM CDT Mon Jun 22 2026

Key Messages:

- Lower MVFR CIGs quickly improving early this morning.

- Breezy northeasterly winds today, with occasional gusts around 20 kt.

The rain has ended and CIGs are beginning to quickly improve across the Chicago area terminals. Accordingly, we should transition to primarily VFR conditions early this morning. The only exception will be at GYY, where some of the low clouds may hang on for another hour or two. Otherwise, primarily dry and quiet weather is expected today with northeasterly winds through the day.

KJB

LOT WATCHES/WARNINGS/ADVISORIES

IL...Beach Hazards Statement through late tonight for ILZ006-ILZ103- ILZ104.

IN...Beach Hazards Statement through late tonight for INZ001-INZ002.

LM...Small Craft Advisory until 1 AM CDT Tuesday for the IL nearshore waters.

Small Craft Advisory until 4 AM CDT Tuesday for the IN nearshore waters.