textproduct: Central Illinois

KEY MESSAGES

- Low-impact weather is forecast through early next week. Look for high temperatures in the upper 60s to mid 70s with occasional sprinkles or light rain showers.

- Notable rain chances return from Tuesday night into the following weekend. There is a 20-50% chance for rainfall to exceed 2 inches, which may lead to ponding of water on roadways as well as localized flooding.

UPDATE

Issued at 930 PM CDT Fri Sep 25 2026

Forecast generally looks on track tonight, with some minor adjustments to the sky cover. Isolated very light rain showers and sprinkles had dissipated during early evening with broken to overcast mid level clouds giving mostly cloudy to overcast skies. 1028 mb high pressure just northeast of the Great Lakes over eastern Ontario will continue ridging southward into the Ohio river valley including IL tonight and Saturday continuing a fairly light east to NE flow into CWA. Some drying from the east and ne to help decrease/scatter out the mid level clouds during overnight/early Sat morning from Peoria to Flora east/ne. A bit cooler lows overnight in the low to mid 50s, coolest in east central IL where mid level clouds decrease first. Isolated to scattered mainly light showers currently west and sw of CWA could move into west central IL from Galesburg to Jacksonville west on Saturday especially late Sat morning and afternoon but amounts would be light again if they happen.

DISCUSSION

Issued at 228 PM CDT Fri Sep 25 2026

Persistent radar echoes moving in from the west since early this morning have only resulted in very light amounts, save for a tenth or so near London Mills (Fulton County). The rain has been battling low level dry air advection from the east, as well as a notable dry layer aloft between about 850 and 700 mb. Points west of the Illinois River have managed to moisten that dry layer the most and stand the best chance for a few more hours of occasional sprinkles or light rain through this evening.

Some locations could see some very light precipitation this weekend in association with a north-south deformation axis, beginning on Saturday primarily west of I-55 and gradually moving to roughly a Bloomington-Effingham line early Sunday morning. Otherwise, the elongated blocking ridge over the Midwest between a western US trough and a closed low over the mid-Atlantic should keep the weather low-impact and relatively dry.

That is forecast to change around the middle of next week, as the trough over the western US begins to move toward the central part of the country, potentially picking up tropical moisture from now-Hurricane Polo as it does so. A slow-moving boundary with perhaps multiple short-wave troughs tracking along it could be a recipe for heavy rain setting up somewhere in the general vicinity. Ensemble solutions are split between a group that features a deeper closed low originating over the southwest US, and a group that features a stronger northern stream trough. The northern stream group has a higher average precipitation amount for central Illinois, but either way there is a 20-50% chance of greater than two inches of precipitation by the end of next weekend, with the higher probabilities west of the Illinois River.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1152 PM CDT Fri Sep 25 2026

VFR forecast this cycle. Ceilings above 7k feet will be common. Scattered -SHRA this afternoon into tonight will be most numerous over western IL, so added VCSH for KPIA-KSPI. East winds around 5 kt will continue.

ILX WATCHES/WARNINGS/ADVISORIES

None.