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KEY MESSAGES

- Generally warm and dry conditions are expected through early next week.

- Daily lake breezes will keep temperatures cooler near the lakeshore with backdoor cold fronts bringing cooler conditions farther inland Thursday and again over the weekend.

- Building waves and dangerous currents are expected at southern Lake Michigan beaches late this evening through Thursday night.

DISCUSSION

Issued at 251 AM CDT Wed May 27 2026

The local area remains situated between two separate disturbances early this morning. The system to our south continues to very gradually lift northeast across the Ohio Valley and may bring a few showers/sprinkles to the far southern forecast area early this morning (mainly south of a Paxton to Rensselaer line). These showers will be encountering an increasingly dry airmass so a sharp gradient is expected along its northern periphery, keeping the rest of the area dry. Meanwhile a stalled surface boundary draped across Wisconsin paired with a weak mid-level wave/vort will likely lead to scattered shower and storm development well to our north this afternoon. These storms may attempt to propagate south toward northern Illinois late this afternoon into early evening. They will be encountering the much drier airmass in place here locally and are expected to erode prior to reaching the state line.

Ample sunshine and fairly deep mixing will support temperatures warming into the mid to upper 80s today for inland areas, with lower 70s possible along the lakeshore before a lake breeze moves inland midday dropping temperatures back into the 60s.

The aforementioned stalled surface boundary is expected to eventually dive southwest as a backdoor cold front across the area into this evening. In addition to steadily falling temperatures, winds will become increasingly gusty out of the northeast in its wake, leading to quickly building waves at area beaches. How early the front arrives remains somewhat uncertain but is generally expected sometime between ~6-9 PM, likely dependent on convective trends in Wisconsin later today. Will have to monitor observations closely through the afternoon in case the start time of the Beach Hazard Statement needs to to be moved up an hour or two. High waves and rip currents then likely persist through Thursday and potentially into Thursday night.

Ensembles continue to support an expansive area of surface high pressure setting up across the region paired with high amplitude ridging extending well into Canada. This increases confidence in continued warm and rain-free conditions across the region into the first week of June. The general position of high pressure will be favorable for onshore winds most days, which paired with daily reinforcing lake breezes will keep temperatures cooler near the lakeshore. There remains the potential for additional backdoor cold fronts at times over the weekend into early next week leading to cooler more seasonable conditions extending farther inland at times.

Petr

AVIATION /12Z TAFS THROUGH 18Z THURSDAY/

Issued at 626 AM CDT Wed May 27 2026

Dry and VFR conditions are forecast through the TAF window. Winds will be light and variable early this morning before becoming more consistently out of the northeast by mid morning. As a dry backdoor front moves south down western Lake Michigan after 00Z, winds will remain out of the northeast but wind gusts are expected to increase to 15 to 20 knots through Thursday morning.

DK

LOT WATCHES/WARNINGS/ADVISORIES

IL...Air Quality Alert until 6 AM CDT Thursday for ILZ005-ILZ006- ILZ012-ILZ013-ILZ020-ILZ021-ILZ103-ILZ104-ILZ105-ILZ106- ILZ107-ILZ108.

Beach Hazards Statement from this evening through late Thursday night for ILZ006-ILZ103-ILZ104.

IN...Air Quality Alert until midnight CDT tonight for INZ001-INZ002- INZ010-INZ011.

Beach Hazards Statement from late tonight through late Thursday night for INZ001-INZ002.

LM...Small Craft Advisory from 10 PM this evening to 10 PM CDT Thursday for the IL nearshore waters.

Small Craft Advisory from 4 AM Thursday to 1 AM CDT Friday for the IN nearshore waters.