textproduct: Chicago

KEY MESSAGES

- Chance of showers southeast third of the area through midday.

- High waves and dangerous swimming conditions will continue at Lake Michigan beaches through Monday morning.

- Chance of thunderstorms with possible heavy rain and localized flooding Wednesday into Wednesday night.

DISCUSSION

Issued at 211 AM CDT Sun Aug 2 2026

Scattered showers will continue southeast of a Kankakee to Valparaiso line through midday with a few showers possible in the far southeast cwa this afternoon. There may also be a few sprinkles or an isolated shower across the rest of the area this afternoon, but confidence is too low to have any mention in the forecast. Still some uncertainty for how fast clouds will clear out today, but clearing is expected this afternoon and this should help high temps to reach the mid/upper 70s for most areas. Northeast winds over land will likely hold in the 15-25 mph range, but gusts over Lake Michigan may still be in the 30-35 mph range through this evening and then winds/gusts will steadily diminish tonight into Monday morning. High waves and dangerous swimming conditions will continue at Lake Michigan beaches through Monday morning with refinement of the end time for the Beach Hazard Statement possible with later forecasts.

High pressure will allow for dry weather tonight through Tuesday evening. A cold front will be moving across the upper Midwest and western Great Lakes Tuesday night into Wednesday, possibly bringing decaying showers and thunderstorms to the area around daybreak Wednesday morning. This front is then expected to move across the area Wednesday afternoon into Wednesday night bringing the next chance for showers and thunderstorms. Models show precipitable water values reaching 2 inches along/ahead of this front and forecast qpf amounts are already in the 1-2 inch range from some models. If this were to materialize, given the recent rains and wet ground, additional heavy rain and localized flooding would be possible. Quite a bit of uncertainty for late week into next weekend as the models struggle with a possible large upper trough moving into the northern Great Lakes and a large upper ridge possibly building in from the Plains. cms

AVIATION /12Z TAFS THROUGH 18Z MONDAY/

Issued at 626 AM CDT Sun Aug 2 2026

Key Messages:

- Lower MVFR/IFR CIGS persist this morning, then bases diurnally improve this afternoon.

- Breezy north-northeast winds, with gusts 20-25 kt during the day. A low MVFR/IFR stratus deck continues to stream into the area early this morning. IFR CIGs are expected, primarily north of the Chicago terminals up around the WI state line (including RFD). While diurnal improvement is anticipated, it will likely be several hours before bases begin to rise to VFR into this afternoon. Otherwise, expect north-northeasterly winds today, with some afternoon gustiness of 20-25 kt, particularly across the eastern terminals.

Winds will abate tonight as a surface ridge axis approaches. Lingering low-level moisture and light winds under this ridge could foster some shallow late night fog development tonight, particularly outside of the main Chicago terminals. Accordingly, we will have to keep an eye on this potential, particularly for RFD and DPA.

KJB

LOT WATCHES/WARNINGS/ADVISORIES

IL...Beach Hazards Statement through Monday morning for ILZ006- ILZ103-ILZ104.

IN...Beach Hazards Statement through Monday morning for INZ001- INZ002.

LM...Small Craft Advisory until 3 AM CDT Monday for the IL and IN nearshore waters.