textproduct: Central Illinois

KEY MESSAGES

- An unsettled period of weather is on tap through the middle of next week. While rain chances are in the forecast nearly every day, there will be plenty of dry periods as well, especially over central IL from Friday night through Sunday morning.

- The risk for severe weather returns Monday afternoon through Wednesday. SPC severe weather probabilities are greater than 15% across west central and northwest IL Monday afternoon and Monday evening, over central and northern IL Tuesday afternoon into Tuesday night and over much of IL on Wednesday.

DISCUSSION

Issued at 245 PM CDT Thu Apr 9 2026

At 19Z/2 pm, a frontal boundary was over northern IL, just north of the Galesburg airport, near Lacon airport and just north of Kankakee airport. The front extended back over nw MO and along the KS/NE border to 1010 mb low pressure in eastcentral CO. Radar mosaic shows isolated showers near the boundary close to I-80 with more widespread showers in central/sw Iowa into eastern Nebraska. A fair amount of sunshine over areas se of the IL river with scattered high base cumulus clouds from I-72 northward and ample sunshine south. Mid/high clouds were spreading into west central and nw IL from Iowa and northern MO. Mild temps were in the lower 70s nw of the IL river and mid 70s to near 80F se of the IL river with breezy sw winds gusting 20-30 mph.

A short wave over the Dakotas will track eastward into the northern Great Lakes tonight, pushing the front se through the IL river valley by early overnight and thru rest of central IL later tonight into Fri morning, and thru southeast IL by mid Fri afternoon. Increasing low level jet and moisture to help develop more widespread convection over nw IL early this evening, and push se into the IL river valley later this evening and early overnight, getting south of I-72 around 3-4 am. The convection to diminish/become more scattered later tonight as it pushes south of I-72 and into southeast IL by Fri morning. Chances of showers and isolated thunderstorms lingers south of I-72 during Friday afternoon and over southeast IL into early to mid Fri evening as front nears Ohio river by sunset Fri. Rainfall amounts of quarter to half inch with local amounts of half to 1 inch over nw CWA, a tenth to quarter inch over heart of central IL, and generally around a tenth inch or less in southeast IL. Lows tonight in the upper 40s to around 50F from Peoria nw and mid to upper 50s from Quincy to Lincoln to Rantoul south. Highs Friday range from lower 60s north of Lincoln and lower 70s se of I-70 (near 75F in Lawrence county).

1028-1032 mb high pressure to build into the central Great Lakes by lower MI by dawn Saturday and move into southern New England by dawn Sunday. Cool ne flow on Friday night to bring a seasonably cool night with lows in the low to mid 40s, with upper 30s possible from I-74 ne. Highs Saturday similar to Friday's highs, with low to mid 60s central IL and upper 60s/lower 70s in southeast IL. We have 20-30% chances of showers over western/sw half of CWA on Saturday with isolated thunderstorms possible Sat afternoon just sw and west of CWA.

As high pressure shifts further east of IL during Sat night, a warm front to lift ne over the area with breezy south to SW winds on Sunday gusting 25-35 mph and some spots reaching 40 mph north of I-70. Warmer highs in the upper 70s to around 80F return on Sunday. We have convection chances Sunday afternoon and Sunday evening west of I-57 with highest pops (40-60%) west of the IL river. Higher chances of convection 50-60% move into eastern IL too overnight Sunday night into Mon morning as a disturbances lifts through. Best chance of severe storms Sunday afternoon/evening appears to stay well sw of IL then where better instability will be.

Warmer and more humid air arrives early next work week, with highs in the lower 80s Monday and low to mid 80s Tue. Dewpoints in the mid 50s to around 60F Sunday rise into the the 60s (even a few spots near 70F) on Mon/Tue. Convection chances appear to become more isolated during Monday afternoon into Tue afternoon but with increase instability may see a few strong to severe cells especially over west central and nw IL. A better chance of convection to arrive Tue afternoon into Wed and SPC has much of central IL in 15% risk or higher on Tue afternoon/Tue night and much of IL has 15% risk or higher of severe storms on Wed. Warm temperatures continue Wed/Thu with highs in the mid 70s to near 80F.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 619 PM CDT Thu Apr 9 2026

A frontal boundary has stalled between PIA and C75 and between BMI and PNT slightly further east. South to southwest winds are favored south of the boundary while a northerly wind is favored north. Uncertainty in the position of the boundary is high in the near term, especially with respect to the wind direction at BMI. Showers and storms will increase in coverage along the boundary and across IA/MO late this evening, and should move across central IL overnight into Friday morning. MVFR ceilings will be possible with any showers on station and are expected to become more widespread behind the front, even dipping to IFR at times, especially at PIA/BMI.

ILX WATCHES/WARNINGS/ADVISORIES

None.