textproduct: Central Illinois

KEY MESSAGES

- Record-breaking heat will continue today south of Peoria, with high temperatures reaching the upper 80s to lower 90s.

- There is a Marginal Risk (level 1 of 5) for severe thunderstorms tonight. Some storms will be capable of producing localized damaging wind gusts and hail.

- Unsettled weather tonight through Thursday will bring periods of wet weather, with around an inch of rainfall likely for most areas, although some intense thunderstorms could result in localized 2 inch downpours.

- A sharp cold front will bring much cooler temperatures Friday through the weekend, bringing a potential for early morning frost both Saturday and Sunday.

DISCUSSION

Issued at 252 AM CDT Tue Oct 13 2026

Most of central and southeast IL will remain under a very warm air mass causing highs to reach the upper 80s to lower 90s again today, likely breaking more daily temperature records. Meanwhile, a cold front will nudge into the vicinity of Peoria, limiting temperatures to a few degrees cooler from Peoria northward. The cold front will likely remain dry through the afternoon in the absence of substantial lift, although low level frontogenesis just to the west along the front could bring a close call for some morning shower activity north of Peoria.

Thunderstorms look to develop along the front over the front from KS through MO in the afternoon today as a shortwave tracks along the front coincident with increased moisture, MLCAPE up to around 2000 J/kg, and around 40 kt deep layer shear. This area of thunderstorms should move and grow eastward, with high-res models depicting storms in the Illinois River Valley withing a few hours after sunset. Models decrease CAPE, especially surface/ML CAPE as thunderstorms move into central IL, however 1000-15000 MUCAPE maintains through Tuesday night. This should result in isolated severe storm potential, and SPC depicts a Marginal Risk in much of central IL as far east as I-57 for a threat of locally damaging wind gusts to 60 mph, as well as a threat for 1"+ hail eastward to around the IL River.

As the front stalls south of the area Wednesday, multiple rounds of showers and thunderstorms are depicted to continue across the area, although with many breaks in activity as well. A strong surface low will finally track through the area Thursday, bringing a likelihood of widespread rain, likely the heaviest of the midweek period. This system will bring a return of strong deep layer shear and moderate instability that could result in severe thunderstorms again. SPC depicts a Marginal Risk for much of the area southeast of the IL River. Model blend brings around 1 to 1.5 inches of precipitation north of I-70 through Thursday, with around 0.75 inches to the south. Nevertheless, some isolated 2+ inch downpours can be expected with thunderstorm activity as shown by several high-res models, and this could be enough for some locally excessive rainfall, despite recent dry conditions. WPC has a Marginal Risk for excessive rainfall over portions of the area Tuesday through Thursday. With cloud cover and periods of rain as well as a cold front located just south of the area, temperatures should be down considerably Wednesday and Thursday, with highs likely to be in lower to mid 70s north of I-72 to upper 70s or lower 80s to the south.

Behind Thursday's low a strong cold front will sweep through the area, bringing much cooler and dry air by Friday. Models have converged on a much narrower range of temperatures than the past few days, with 10th-90th percentile range only around 10 degrees. This should result in Highs Friday and Saturday around 60 (plus or minus 5 degrees), and lows mid to upper 30s Friday night and Saturday night (plus or minus 5 degrees). With the high perhaps directly overhead Saturday morning, this would be the best chance for frost or freezing conditions.

As high pressure moves off to the east Sunday, a strong return of warm air will bring a warming trend through early next week, resulting in highs rebounding to nearly 70 degrees Sunday, lower to mid 70s Monday, and mid to upper 70s Tuesday.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 552 AM CDT Tue Oct 13 2026

A weakening low level jet should allow for an end to low level wind shear by 12Z-13Z this morning. Although isolated morning showers could affect KPIA and KBMI, conditions will be primarily dry until showers and thunderstorms spread into the area from the west this evening. Uncertainty in timing continues, however mentionable chances begin around 02Z at KPIA to around 06Z at KDEC and KCMI. Scattered showers and thunderstorms look to continue the remainder of the night. Storms may produce local MVFR cigs/vsbys, otherwise predominant conditions look to remain VFR through the period. Winds SW 8-12 kts this morning, weakening by this evening to light and variable.

CLIMATE

Issued at 1220 AM CDT Tue Oct 13 2026

Record high temperatures:

Location Tuesday Latest 90 deg. High ======== ======= =================== Bloomington 91/1899 October 15, 1899 Champaign 86/1989 October 14, 1899 Charleston 87/2017 October 15, 1897 Decatur 90/1899 October 15, 1938 Jacksonville 91/1899 October 30, 1950 Olney 93/1928 October 22, 1953 Peoria 88/1899 October 15, 1897 Springfield 88/1975 October 12, 2026

ILX WATCHES/WARNINGS/ADVISORIES

None.