textproduct: Central Illinois

KEY MESSAGES

- An elevated fire risk will materialize across west-central Illinois on Tuesday due to strong winds and afternoon relative humidity values potentially dropping below 30%.

- There is a high (70%) chance for light wintry precipitation Wednesday night into Thursday morning in areas north of Interstate 70.

DISCUSSION

Issued at 211 AM CST Mon Feb 23 2026

A potent Nor'easter continues to impact New England, while elongated high pressure remains situated to our west. This tight surface pressure gradient is responsible for the ongoing cold and blustery conditions across the Great Lakes this morning. Expect wind gusts of 20-25 mph to be common through midday, resulting in wind chill values near zero to start the day. Winds will quickly diminish late this afternoon as a ridge of high pressure builds in overhead.

Cool temperatures will persist this afternoon, with daily average highs around 30 degrees, placing them 5-10 degrees below late- February norms. Tonight, temperatures will again settle into the teens.

A quick warm-up is anticipated starting Tuesday as a broad ridge axis moves across the central U.S., causing a quick increase in mid-level heights. This pattern change will usher in much milder conditions. Warmer air will be brought into the Midwest by strengthening southwest winds ahead of an approaching cold front, with an added boost from down slope flow off the Rockies.

Tuesday afternoon presents an elevated fire danger, particularly across west-central Illinois. This is due to forecast highs well into the 40s, accompanied by gusty winds of 30-40 mph. The combination of gusty winds, mild temperatures, dry fuels, and low afternoon relative humidity (around 25%) warrant attention given our current dry spell. However, increasing high clouds could potentially mitigate this threat by decreasing boundary layer mixing and subsequently raising relative humidity values, introducing some uncertainty to the overall fire potential.

A cold front will settle just south of the region late Tuesday night, keeping us on the cool side of the boundary on Wednesday with afternoon highs near 40 degrees. This boundary will then slosh back northward late Wednesday night and into Thursday morning. This shift will occur as a strong shortwave and associated surface low track across the Corn Belt, bringing forth our next weather-maker.

The midweek event is shaping up to be more complex than earlier winter episodes, primarily due to the surface front bisecting central Illinois. This sets the stage for mixed-phase precipitation. While the latest NBM guidance indicates a high (about 70%) likelihood of measurable precip, thermal profiles will require close monitoring as the event nears. The best chance (40-60%) for 1 inch or more of snow remains north of a Macomb to Champaign line. South of this area, probabilities quickly decrease as a transition to sleet or freezing drizzle is possible later Thursday morning as the system departs eastward.

Quiet and mild weather returns by the end of the week as a ridge of high pressure settles in behind the departing midweek storm system. Temperatures for Friday and Saturday look to be squarely in the 50s until a backdoor cold front sags across the area by late this weekend, pushing temperatures back down toward seasonal norms for Sunday and Monday.

MJA

AVIATION

(For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1139 AM CST Mon Feb 23 2026

MVFR ceilings will persist at KBMI/KCMI for the next hour or two as the cloud cover continues to scatter and shift eastward. Once these clouds depart, a period of mostly clear skies will prevail before mid-level clouds AOA 12,000ft increase from the west tonight into Tuesday morning. Winds will initially be NW at 10-15kt early this afternoon, then will become light/variable this evening as high pressure moves overhead. Once the high shifts into the Ohio River Valley and the pressure gradient tightens, strong/gusty SW winds will develop on Tuesday. Gusts will increase to 30-35kt toward midday.

Barnes

ILX WATCHES/WARNINGS/ADVISORIES

None.