textproduct: Central Illinois

KEY MESSAGES

- Several shower and storm chances exist through the next 7 days. Saturday having the best potential for widespread dry conditions. Severe weather and flash flooding are not expected at this time over the next few days.

- Favorable pattern for increased heat/humidity (heat indices nearing 100F) and thunderstorm complexes Sunday into Tuesday. There is a 50-80% chance of heat indices being greater than 95 degrees on Monday afternoon, south of I-74/Danville.

DISCUSSION

Issued at 223 AM CDT Thu Aug 6 2026

The surface front has stalled out over northern IL at this point. That and some upper level (500mb) vort maxes together will bring several more rounds of showers and potentially thunderstorms across the state into the weekend.

Today the rain is primarily near and south of the I-72 corridor. It is uncertain just how far much further north the rain will extend but some scattered activity is not out of the question. There already is some activity approaching the southwest CWA now (~07z) from the convection in central/northern MO, which will continue to spread east through the morning into the early afternoon. Severe weather and flash flooding are not expected at this time over the next few days. Some areas that see multiple heavy showers/storms move through could see some ponding or full ditches though.

Seasonable temperatures are expected to last into Saturday. Then, temperatures look to rise near or above 90 degrees for highs with increasing humidity. The warmest days of the forecast being Sunday into Tuesday (Monday being the hottest day). The LREF shows a 50-80% chance of apparent temperatures being greater than 95 degrees on Monday afternoon, south of I-74/Danville. However, Sunday through Tuesday, multiple convective areas will move across northern and central IL. The heat indices and actual temperatures may not be able to achieve 90 degrees because of the additional rain/cloud cover. Wednesday and Thursday next week looks to cool back off with highs in the upper 70s to low 80s.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1242 AM CDT Thu Aug 6 2026

Isolated to scattered thunderstorms are possible for much of the upcoming 24 hours as a frontal zone remains stalled over the area. In the next few hours, any thunderstorm activity should be too isolated for mention in TAFs, however scattered showers could bring brief MVFR conditions. An area of thunderstorms over MO should migrate eastward overnight, most likely to affect KSPI and KDEC from around 8-12Z. After 16Z-18Z, probabilities for showers and thunderstorms become too low for mention in TAFs while MVFR cigs gradually improve to VFR until another disturbance in the evening brings chances for thunderstorms worthy of a PROB30 mention along the I-72 terminals KSPI-KDEC- KCMI. Winds generally E 3-6 kts overnight then becoming S-SW 4-7 kts by 15Z.

ILX WATCHES/WARNINGS/ADVISORIES

None.