textproduct: Central Illinois

KEY MESSAGES

- Comfortable conditions through Thursday: Dry air and low humidity will keep afternoon temperatures in the 70s with pleasant, cool nights through Thursday night.

- Storm chances south on Friday: A 30-50% chance for thunderstorms exists southwest of a Macomb-to-Paris line Friday afternoon into Friday night. Heavy rain and gusty winds are the primary concerns.

- Dangerous heat returning Sunday-Monday: Highs reach the mid-90s with heat index values peaking near 105 F.

- Severe weather and flash flood risk early next week: There is a 20-30% chance for storms and heavy rain Sunday into Monday. Drier, cooler air arrives by Tuesday.

Post Frontal Relief By Tuesday

The surface cold front is projected to clear central Illinois by early Tuesday, sweeping out the oppressive mid-70s dewpoints and substituting them with more palatable 60s. Highs fall back into the mid-to-upper 80s, easing overall heat risk. Northwest flow aloft behind the trough will be worth monitoring for additional upstream waves (particularly Tuesday night into the Great Lakes), but the dominant base-case scenario through midweek points to dry, seasonably warm weather.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 525 AM CDT Wed Jul 22 2026

VFR conditions will dominate this TAF period as surface high pressure slowly builds across the regional terminals. The brief exception could be this morning as a scattered stratus deck continues a southwest push, with occasional bases between 2-4 kft. These low clouds will mix away later this morning, but will be replaced by a deck of diurnal cumulus (4-7 kft) this afternoon. Skies then become mostly clear this evening with the loss of daytime heating.

ILX WATCHES/WARNINGS/ADVISORIES

None.