textproduct: Central Illinois

KEY MESSAGES

- There are no signs over the next week of the warmer weather pattern breaking down, with high temperatures 10 to 20 degrees above normal. There is a 30 to 40 percent chance of high temperatures reaching 80 degrees on Thursday near and south of I-70.

- While some sprinkles or very light showers will be possible on Thursday north of I-72, any significant rain chances are likely to hold off until early next week. Best chances of seeing more than an inch of rain will be near and west of I-57 (50-60% chance) Monday through Wednesday.

- While rain chances are expected Saturday morning north of I-72, dry conditions are expected for any miscellaneous outdoor activities later in the day.

DISCUSSION

Issued at 145 PM CDT Wed Oct 28 2026

Skies are mostly sunny across the forecast area early this afternoon, though some patches of altocumulus were observed west of the Illinois River. Regional radar mosaics show a few echoes associated with some weak isentropic lift, now in far west central Illinois. GOES-East satellite sounding from near Peoria shows that moisture is pretty sparse below 7,000 feet, so a few sprinkles are all that is expected.

Short Term (through Halloween):

A shortwave currently over the western Dakotas will lift northeast into western Ontario by late tonight, with a trailing surface boundary moving across central Illinois on Thursday. This boundary will become nearly stationary near or south of I-70 later Thursday, as it lines up with the upper flow. Some increase in low level moisture is expected ahead of the front, as dew points rise into the mid 50s to near 60. Mid-level lapse rates may be enough to trigger a few showers in the afternoon toward Bloomington-Danville, though most will be further northeast. Sprinkles may be more likely over the northern CWA, though. With the front laying out west-east, there will be more of a temperature gradient Thursday and Friday, with highs still near 80 degrees near and south of I-72/Danville Thursday.

Late in the week, the front begins lifting north again as a shortwave digs over the central Plains. High pressure will still be feeding drier air in from the east, with any associated showers most likely near and west of the Illinois River. Rain chances continue to increase as the wave gets closer, but mostly will be north of I-72 into Saturday morning. Conditions are looking dry for outdoor activities late Saturday afternoon into the evening. While Saturday remains fairly cloudy, temperatures still will be well above late October normals, with highs mainly in the lower 70s and evening temperatures in the 60s.

Long Term (Sunday through Wednesday):

A wholesale pattern change will be taking place next week, providing more opportunities for some needed rainfall. The synoptic models continue to develop a large, cutoff upper low over the central Plains early next week, with an associated surface cyclone intensifying. GFS solutions are the more intense of the group, while the European solutions are slower and more influenced by a separate low skirting the northern border of Minnesota. The latter camp would suggest more dry weather Sunday and Monday, while the former provides more numerous rain chances from Sunday all the way through next Thursday. In any event, this does appear to be the best rain chances we have seen in some time. Overnight LREF guidance shows a 50-60% chance of seeing more than an inch of rain in areas west of I-57, though this has trended down some from the previous run. The fine details of cutoff lows are always a challenge to pin down this far in advance, though.

Morning NBM guidance came in warmer for early next week, with mainly lower 70s for highs, but clouds and rain extent will probably temper this down somewhat.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 642 PM CDT Wed Oct 28 2026

S winds of 5-10kt will prevail through the evening before gradually veering S/SW overnight. As a cold front approaches, winds will become W/SW and increase to 10-15kt after 14z Thu. Based on model consensus, the front will pass and winds will veer to NW at KPIA by 20z and further south at the I-72 terminals by 22z. Other than FEW-SCT mid-level clouds, skies will remain partly to mostly clear until the front arrives. The latest HRRR/RAP guidance continues to suggest a band of MVFR ceilings impacting KPIA and perhaps KBMI before diurnally rising to low VFR by the time it reaches KSPI/KDEC/KCMI. Given increasing confidence, have added a period of MVFR during FROPA at KPIA...but kept other sites VFR.

ILX WATCHES/WARNINGS/ADVISORIES

None.