textproduct: Central Illinois

KEY MESSAGES

- Dry fuels and low relative humidity will lead to an elevated risk for afternoon agricultural field fires today, Thursday, Friday, and Saturday, especially southeast of the Illinois River.

- The next notable chance for rain is Sunday. The greatest (20-30%) chance for more than one-half inch of rain is south of I-70.

DISCUSSION

Issued at 238 PM CDT Tue Oct 6 2026

This afternoon, central Illinois is sandwiched between a surface high centered over the mid-Atlantic and a surface low moving across Ontario. Though the latter system is displaced fairly far to the north, the pressure gradient has tightened a little with a number of gusts to near 20 mph observed. This, combined with relative humidity dropping into the 25-35% range, will contribute to an elevated risk for agricultural field fires. This risk will be particularly notable south of about Springfield-Mattoon, where conditions are classified as abnormally dry due to extended precipitation deficits. Moisture pooling along a weak boundary moving in from the northwest on Wednesday morning should keep RH values higher on Wednesday afternoon. Dry afternoon conditions should return each day from Thursday through Saturday, continuing the elevated field fire risk.

Our next notable chance of rain hinges on the evolution of the developing potential tropical system in the Gulf, and the track it eventually takes. Though variability is still high with the greatest chances of heavy rainfall to our southeast from the Gulf coast into the mid-South and the upper Ohio Valley, the EFI product shows a SoT contour encompassing southeastern Illinois, indicating that the top 10% of ensemble members are above the 99th climatological percentile for QPF/forecast precipitation. Looking at the entire ensemble envelope, the chances of greater than 0.50" of precipitation at any given location in the southeastern portion of the ILX CWA with this event are only in the 20-30% range. However, those high-end members are there, and this system bears watching.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 644 PM CDT Tue Oct 6 2026

VFR conditions will prevail through the entire 00z TAF period. Winds will be S/SW at less than 10kt tonight, then will veer to W/SW and increase to 10-15kt ahead of an approaching cold front Wednesday morning. The cold front/wind shift will pass KPIA by 17z...then further south to the I-72 terminals by around 20z. Winds will veer to NW after FROPA. Skies will initially be clear tonight, but high clouds will increase/thicken late tonight through Wednesday as the front passes.

ILX WATCHES/WARNINGS/ADVISORIES

None.