textproduct: Central Illinois

KEY MESSAGES

- There is a Slight Risk (level 2 of 5) for severe weather late tomorrow afternoon and evening. The primary hazards will be damaging wind gusts and large hail: however, an isolated tornado cannot be ruled out.

- Large temperature swings are in store for the remainder of the week. Readings will soar to record warm levels in the upper 80s to near 90 tomorrow afternoon...then will plunge into the upper 20s by early Saturday morning.

DISCUSSION

Issued at 219 AM CDT Wed Mar 25 2026

A high pressure system is sitting over eastern U.S again today, bringing gradually increasing temperatures ahead of the low pressure system Thursday. The warmest highs are on Thursday have a 60-90% chance of exceeding 80 degrees across the entire forecast area and a 60-80% chance of greater than 85 degrees west of Highway 51, based off the NBM and HREF probabilities. We are looking at blowing away the record highs for Thursday, and maybe even record monthly highs, as the records are around 78-85 degrees. (See climate section for locations and records)

Thursday's low pressure system will be accompanied with the warm front lifting north on Wednesday night and a strong cold frontal passage Thursday. The warm front could bring some showers and elevated thunderstorms to central IL late this evening into early tomorrow morning.

The cold front is bringing strong to severe storms, potential excessive rainfall, and a sharp drop off in temperatures again. SPC has maintained central IL a slight risk (level 2 of 5) for severe weather for this event. All hazards are in play, large (potentially 2+ inch) hail, damaging winds, and a few tornadoes. SPC suggests that if there is a tornado, there is the chance for it to be of EF2 or greater strength. Timing looks to have the storms entering the forecast area from the north around 22-00z tomorrow and exiting to the south by 08-10z Friday morning. The environment, based off forecast soundings, looks to be primed but will have to fight a cap initially, but as the front approaches, the cap will erode. MUCAPE values of 2300-2800 J/kg, with 45-60 knots of bulk wind shear. Lapse rates sound alarm bells for significant hail sizes with insane values of 8-8.3 C/km. Then the PWATs, which are around 1.5- 1.8, and the long skinny CAPE profile suggest that these storms could be efficient rain producers. The WPC maintained a marginal risk for excessive rainfall for day 2.

Behind the front, lows Thursday night will dip down into the mid 30s to low 40s. Highs on Friday won't be much warmer, with values in the upper 40s nearing 50. As of now, there is a 50-80% chance that temperatures will get back above 75 degrees by next Monday.

The Climate Prediction Center 8-14 Day outlook (first week of April) has 60-80% chance of above normal temperatures over IL with precipitation trending 40-60% chance above normal. So the mild and wet/unsettled pattern looks to continue into early April.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1203 AM CDT Wed Mar 25 2026

Periods of mid and high based ceilings will continue the next 24 hours, but will ease below 10kft Wednesday evening. Expect southeast winds to become more southerly and average 10-12 knots from midday through the evening. Some uncertainty with the extent of potential thunder development Wednesday evening, and have kept PROB30 groups limited to the KPIA-KCMI corridor for now.

CLIMATE

Issued at 125 AM CDT Wed Mar 25 2026

Forecast temperatures on Thursday may exceed March records in some areas.

Mar 26 Record March Record Charleston.... 84 (1907) 89 (3/24/1929 and 3/22/2026) Decatur....... 83 (1907) 89 (3/24/1929) Jacksonville.. 83 (1950) 91 (3/1/1907) Lincoln....... 83 (1991) 86 (3/29/1985 and 3/30/1986) Normal........ 83 (2007) 88 (3/21/1907) Olney......... 85 (1907) 89 (3/24/1910 and 3/24/1929) Peoria........ 82 (1907/1991) 87 (3/21/1907) Springfield... 81 (1991) 91 (3/21/1907) Urbana........ 81 (1907) 85 (3/21/1907 and 3/24/1910)

ILX WATCHES/WARNINGS/ADVISORIES

None.