textproduct: Central Illinois

KEY MESSAGES

- An isolated shower or thunderstorm may occur near the Indiana border early this morning. Severe weather is not expected.

- A storm system will spread widespread showers and thunderstorms into central Illinois overnight Thursday night into Friday. There is a marginal risk (level 1 of 5) of severe thunderstorms west of I-57 after midnight Thursday night for damaging winds. There is a marginal risk of severe storms in southeast IL along and south of I-70 on Friday.

DISCUSSION

Issued at 345 AM CDT Wed Apr 22 2026

The 08Z/3 am surface analysis shows a cold front over central Iowa to along the IL/WI border and extending into southern lower MI. SW winds keeping mild temps in the low to mid 60s at 330 am with Rantoul at 58F. A weak short wave was producing isolated to scattered convection over central and southeast IN into southern and eastern Ohio, and tracking ESE. It's been dry over central and southeast IL past several hours with this convection staying east of IL. Front to push se into northeast IL and northern IN this morning, and getting south of I-80 during this afternoon but staying ne of CWA today. CAMs show some redevelopment of convection during the afternoon into northern IN and shifting into central IN during this evening. We have just slight chance of convection ne of Danville during mid/late afternoon with most of CWA being dry today. SPC Day1 outlook keeps marginal risk of severe storms in northeast IN and northern Ohio this afternoon/evening for damaging winds and hail where better forcing and instability will be. Partly sunny skies overall on this Earth Day (April 22) with mild highs in the upper 70s to around 80F with sw winds 8-15 mph and gusts to 20 mph.

The front to lift back ne of IL during overnight as strong low pressure over nw MT tracks eastward along the northern ND border tonight. Fair wx expected tonight over CWA with mostly clear skies. Lows tonight in the mid 50s in southeast IL and upper 50s to near 60F in central IL. Breezy southerly winds develop on Thu with gusts to 30 mph. Partly to mostly sunny skies and warm highs in the lower 80s from I-55 west and near 80F in eastern IL. Strong low pressure passing north of MN by daybreak Fri to push a cold front to near the IA/IL border early Fri morning. Will see 20-30% of convection into areas nw of the IL river by late Thu evening, then increasing chances of convection from west to east during overnight Thu night, though eastern IL pops are only 20-40% by late Thu night. SPC Day2 outlook has expanded marginal risk of severe thunderstorms for damaging winds further east into central IL (west of I-57) overnight Thu night. The slight risk is west of IL over Iowa, southern MN and nw half of MO where tornado and hail risks where instability and wind shear is stronger. Mild lows Thu night in the lower 60s.

Cold front to push east/se across IL during Friday bringing high chances of showers and some thunderstorms. SPC Day3 outlook has marginal risk of severe storms in southeast IL from I-70 south Fri afternoon for damaging winds and possible hail while slight risk is over AR and southern MO. A bit cooler Friday with highs in the mid 70s and breezy SSW winds turning west to WNW after frontal passage during Fri afternoon. Have chances of showers and isolated thunderstorms in east central and se IL Fri evening mainly into mid Fri evening. Lows Fri night in the upper 40s to around 50F over the IL river valley and mid 50s in southeast IL.

A pleasant weekend ahead for central/se IL as frontal boundary pushes southeast of the Ohio River by dawn Saturday and into the central Gulf Coast States by dawn Sunday. Weak high pressure moving into the Northern Plains and northern Great Lakes this weekend to bring the fair wx to the area this weekend with mostly sunny skies Saturday and increasing clouds during Sat night and Sunday. Mild temperatures with highs in the low to mid 70s this weekend.

The next storm system looks to affect IL on Monday with more showers and thunderstorms likely as a mid/upper level trof moves eastward along with associated cold front. May be risk of severe storms Monday afternoon especially south of I-72 per CSU-MLP and older SPC Day 7 outlook (15% risk severe southern IL just south of CWA). Highs in the mid to upper 70s Monday cool to more seasonable levels in the mid 60s to near 70F Tue/Wed and lows in the upper 40s/lower 50s.

The Climate Prediction Center (CPC) 8-14 Day Outlook for Apr 29-May 5th has a 40-50% chance of below normal temperatures over IL with precipitation trending near normal over much of IL.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 606 AM CDT Wed Apr 22 2026

A weak frontal trough will remain over northern Illinois today with a modest SW breeze in place ahead of this feature across central Illinois. Gusts to around 20 kt are expected by late morning through around sunset this evening. MVFR ceilings currently spreading east across MO are expected to stall before reaching the central Illinois terminals but bears watching. In addition, a brief period of MVFR ceilings as diurnal cumulus forms is possible, but confidence is lowering on this as well. As such VFR conditions are now favored through the period.

ILX WATCHES/WARNINGS/ADVISORIES

None.