textproduct: Central Illinois

KEY MESSAGES

- Cooler and less active weather is on deck for this week, but it won't be completely dry. There is a 50-70% chance for showers and thunderstorms tomorrow night through Wednesday night as a front pushes south across the area and stalls near southern Illinois.

- Temperatures for the next 7 days will be in the upper 70s to lower 80s for highs and 60s for lows. The CPC 6-10 and 8-14 day outlooks show a 40-60% chance of above normal temperatures returning through the end of the month.

DISCUSSION

Issued at 144 PM CDT Mon Aug 17 2026

Dry and much cooler weather will continue one more day through tomorrow as high pressure moves across the area. Overnight lows should be around 60 with highs tomorrow ranging from 80 to 85. Tomorrow afternoon, and frontal boundary will begin to push toward northwest IL with a chance of showers and storms in the far northwest to northern parts of the CWA. This will last into tomorrow evening, but then after midnight, these showers and storm will finally begin moving to the southeast into the rest of central IL. POPS increase late tomorrow night into Wed morning as a wave along the front moves across areas south of I-72/Danville. These high pops will continua into Wed afternoon across the central part of the CWA and then into out southeast for Wed night. Another break in the weather is then expected Thur and Thur night as another high pressure moves across the area. After this high pressure passes, sporadic small chances of precip return for the end of the week and into the weekend. Though precip will be possible, lots of areas will see dry weather as well.

Through the forecast period much cooler temperatures are expected. High temperatures will be in the upper 70s to lower 80s, while lows should remain in the 60s. Looking at the next 6-10 and 8-14 days, the forecast shows above normal temperatures through the end of the month.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1207 AM CDT Mon Aug 17 2026

VFR conditions will prevail at all TAF sites next 24hrs. Based on satellite trends, would expect scattered clouds at most sites with possible broken clouds at CMI for a few hours. Then expecting clear skies through the night and into tomorrow morning, or some high cirrus. Winds will be northwest around 10kts this afternoon into this evening, then become light and variable overnight as high pressure moves across the area. Tomorrow morning winds will become southwest at less than 10kts.

ILX WATCHES/WARNINGS/ADVISORIES

None.