textproduct: Central Illinois

KEY MESSAGES

- Rain chances will gradually settle southward into the evening. There is a greater than 80% chance of seeing a half inch of rain in areas south of I-70, though totals over an inch would not be out of the question.

- While there will be a brief warmup on Saturday (highs reaching 75-80 degrees), a more substantial warming trend will hold off until mid to late next week.

DISCUSSION

Issued at 143 PM CDT Fri May 8 2026

Latest water vapor imagery shows a series of shortwaves extending from western Ontario into Kansas. Showers have been tracking eastward across the forecast area the last few hours. With time, this area of rain will settle south through this evening, as the waves move across Wisconsin and Illinois. By midnight, the rain should be limited to areas south of I-70, but exiting before sunrise. HREF guidance has a >80% chance of at least a half inch of rain near/south of I-70 through tonight, though the LPMM suggests potential for over an inch just south of I-70.

The next wave is scheduled to drop into the area by early Saturday evening. The bulk of the precipitation with this feature should be post-frontal, though some of the high-res models are suggesting a few showers may sneak into the far northern CWA late afternoon. Ahead of the front, temperatures should be able to reach close to 80 degrees across west central Illinois, but with more troughing settling into the Great Lakes, high temperatures return to the 60s to start the new week.

As we go further into next week, the persistent upper ridge over the western U.S. will gradually edge its way eastward. As this occurs, additional shortwaves will drop southeast along the periphery, with additional rain chances Tuesday/Tuesday night and again toward Thursday night or early Friday. However, the international models are showing signs of developing a blocking pattern late week, with low pressure loitering off the mid- Atlantic states. A gradual warming trend is expected with the ridge, and the blocking pattern would result in warm weather from late next week and persisting into the following week.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 633 PM CDT Fri May 8 2026

An corridor of light rain that extended through the I-72 terminals in recent hours will gradually settle southward this evening, yielding VFR conditions after some areas of MVFR vsby around 00Z. Overnight, this area will continue to move southeastward, while skies gradually clear overnight in central IL. However, late in the night some vsby reduction may occur in fog due to recent rainfall, however continued light winds are expected to keep most vsbys MVFR category or better. Rain is expected to hold off until after 00Z with the next approaching disturbance. Winds SW 6012 kts overnight, becoming W 12-16 kts with gusts 20-25 kts by 18Z.

ILX WATCHES/WARNINGS/ADVISORIES

None.