textproduct: Central Illinois

KEY MESSAGES

- Comfortable weather through Thursday: Dry conditions and low humidity will persist across central and southeast Illinois, with high temperatures in the mid-80s and light winds.

- Heavy rainfall potential and tracking uncertainty: A slow- moving system will bring heavy rainfall and tropical-like moisture Friday into Saturday, creating a risk for localized flooding and road ponding. High confidence for widespread rainfall exceeding 1" targets areas near and north of I-74, while confidence decreases south of this corridor where lighter amounts (0.50" to 0.75") are expected depending on the low's track.

- Cooler weekend, warming next week: Cloud cover and rain will keep weekend highs capped in the mid-to-upper 70s before dry, seasonably warm weather returns early next week.

Heat and Humidity Return By Mid-next Week

Upper-level height rises and an amplifying western ridge will build back into the Great Lakes early next week, bringing a return to seasonably warm and dry weather for Monday and Tuesday. The next opportunity for showers and thunderstorms arrives mid-week as a robust northern-stream shortwave drives a cold front into the Upper Midwest. However, confidence in frontal penetration into central Illinois remains low as primary upper-level forcing rapidly displaces east.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1126 AM CDT Wed Jul 29 2026

VFR conditions will prevail throughout this TAF period as surface high pressure slowly builds across the regional terminals. Surface winds will remain light, gradually veering from northeast to southeast through the period as surface high pressure begins to depart.

Shallow patchy fog may develop overnight into Thursday morning, perhaps lowering visibility for a brief time.

ILX WATCHES/WARNINGS/ADVISORIES

None.