textproduct: Central Illinois

KEY MESSAGES

- Flooding continues across portions of east central IL in a corridor from Champaign to Vermilion County due to 4 to 6 inches of rain that fell yesterday and additional rain moving through this morning.

- Additional clusters of thunderstorms are forecast again late this afternoon into this evening across the area. SPC has a slight risk (level 2 of 5) south of Springfield to Paris line and a marginal risk (level 1 of 5) for areas south of a Rushville to Bloomington line for damaging winds.

- Cooler and less active weather is on deck for Monday through Tuesday. Highs will be in the 80s and dry weather is expected.

DISCUSSION

Issued at 235 PM CDT Sun Aug 16 2026

Cluster of storms near Decatur will continue to move east through the late afternoon and evening hours. HRRR model has finally caught onto it and based on the continued cold cloud tops on satellite and unstable airmass out ahead of it (SBCAPE over 4000 and MLCAPE over 2500) believe this cluster will keep going and will produce scattered wind damage.

Besides the ongoing cluster of storms, scattered showers and storms will remain possible late this afternoon into this evening as a frontal system drops through the CWA. Winds have already begun to turn northwest over parts of northern IL and that will continue as the front moves south. Airmass behind the current cluster has stabilized some and think that chances of convection in west central IL may not be as high. Current mesoscale analysis suggests best instability remains in eastern IL and this could get scoured out as well once this cluster moves into IN. Though airmass does not look favorable at the moment, some recover is still possible with all the cloud-free skies back in MO. So will keep evening chance pops over most of the area with only likely pops south of a Springfield to Paris line. If recovery does not occur, these could be pulled back. The evening convection is expected to develop in west central Illinois as a remnant MCV from northwest MO move into the area and interacts with the front moving south. This convection is expected to move east as well and affect areas where the SPC slight risk is located at. This reasoning is the support for the higher pops in the forecast, mentioned earlier.

A brief break in the active weather and the heat looks likely for Monday into Tuesday. A high pressure center will set up over the Upper Mississippi Valley/Great Lakes region behind a front that is currently moving through IL. Temperatures starting Monday into much of the next week will be mainly in the upper 70s to 80s for highs and 60s to low 70s for lows.

More showers and storms re-enter the area for Tuesday evening into Wednesday night. SPC has a marginal risk for severe weather for Tuesday night west of I-55, with damaging winds the most likely threat. There are additional chances for rain through Thursday before returning to a mostly dry forecast into the late week.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1150 PM CDT Sun Aug 16 2026

Winds will continue to veer northwest over the next several hours as a cold front pushes farther southeast of the terminals. Speeds will increase to around 10 kt during the daylight hours with a few gusts near 20 kt, but gusts look sporadic enough to not include in TAFs. Patchy MVFR visibilities are likely in light fog early this morning, and added a TEMPO group to account for this. Otherwise VFR conditions expected with SCT-BKN mid level clouds.

ILX WATCHES/WARNINGS/ADVISORIES

None.