textproduct: Central Illinois

KEY MESSAGES

- Widespread showers along and southeast of the IL river this afternoon, with isolated thunderstorms possible south of I-70, will gradually diminish during mid evening into early overnight. - Cool weather will continue the next few days, with milder temperatures the end of the week, with highs 75-80F on Saturday. There is a good chance (40-50%) for showers and thunderstorms Friday afternoon and evening and Saturday night into Sunday. The severe weather risk appears low at this time.

UPDATE

Issued at 1055 AM CDT Tue May 5 2026

Updated the forecast today and evening to adjust chances of showers, with one batch of showers exiting east of I-57 late this morning and another batch of showers spreading into west central IL from central/northern MO. The 2nd batch of showers to spread ENE across central and southeast parts of CWA (mainly se of the IL river) next few hours and HRRR and other CAM members fairly consistent in showing this. Have isolated thunderstorms in southeast IL with additional half to 1 inch of rain expected. SPC Day1 outlook has marginal risk south of CWA into southern reaches of Wabash and Edwards counties for 5% risk of damaging winds. Showers to diminish during mid/late evening. Cold front was in far southeast Lawrence county, just passing through Lawrenceville and will push southeast toward the Ohio river early this evening. Also lowered high temperatures a few degrees over central portions of CWA with a fair amount of low clouds and north to NE winds. Highs mostly in the mid to upper 50s with lower 60s in far southeast IL, a much cooler day than yesterdays highs in mid 70s to lower 80s.

DISCUSSION

Issued at 245 PM CDT Tue May 5 2026

The mid afternoon surface map shows the cold front over central Ohio into southeast IN and far southeast parts of IL and MO Bootheel. A 2nd wave of showers has spread ENE over central IL during past few hours and was southeast of a Minonk to Peoria to Macomb line. Isolated thunderstorms were in southern IL, south of I-64. Some upper level forcing helping to produce showers well north of the cold front that is approaching the Ohio river late today and expect widespread showers se of Peoria into early evening, and diminish during mid to late evening (lingering in southeast IL into early overnight). Between a half and 1 inch of additional rainfall possible in southeast IL by midnight with a tenth to quarter inch over heart of CWA near I-72 and I-55 corridor. Continued mention of isolated thunderstorms in southeast 8 counties into early evening. WPC Day1 continues marginal risk of excessive rainfall se of a Terre Haute to Flora line into this evening. Cooler lows overnight in the lower 40s in central IL and mid 40s in southeast IL.

A weak short wave could bring slight chance of light rain showers or sprinkles to sw CWA Wed morning from Springfield sw. Generally a drier day though and cool with mostly cloudy skies. Highs Wed in the upper 50s to near 60F which is quite a bit below normal highs in early May in low to mid 70s. Weak high pressure settling into IL Wed night to bring our coolest night in the upper 30s to around 40F. Could even be patchy frost late Wed night/early Thu morning ne of I-74. Large mid/upper level trof over the Midwest during mid week into Thu keep temps below normal with highs Thu in the low to mid 60s with partly sunny skies.

A northern stream short wave diving down into the area on Friday to bring a good chance of showers and isolated thunderstorms by Fri afternoon/evening. Breezy sw winds ahead of this system brings milder highs in the upper 60s to around 70F. Even warmer on Saturday with highs 75-80F (with lower 80s in west central IL) and dry conditions with a bit breezy WSW winds.

Extended models showing another disturbance returning chances of showers and thunderstorms Sat night into Sunday. Models trending quicker ejecting system away from IL later Sunday so we may trend drier Sunday afternoon on Mothers Day especially over IL river valley. Highs on Sunday/Mothers Day is upper 60s/lower 70s. Dry weather expected early next work week with temps moderating from highs in upper 60s/lower 70s Monday to mid to upper 70s next Tue.

Milder temperatures expected to return to the area during mid and late next week. The Climate Prediction Center 8-14 Day Outlook for May 13-19th has a 35-40% chance of above normal temperatures and precipitation over Illinois.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 602 PM CDT Tue May 5 2026

Showers will continue through this evening, pushing south of all the terminals by around 05Z. North winds become light and variable overnight, then back to the northwest by mid to late morning with speeds between 7-10 kts and occasional gusts approaching 15 kts. Overcast skies will persist the next 24 hours, but ceilings are expected to remain VFR.

ILX WATCHES/WARNINGS/ADVISORIES

None.