textproduct: Central Illinois

KEY MESSAGES

- Bitterly cold wind chills as low as -5 below are expected tonight, especially west of I-55. There is a 60-80% chance for sub-zero wind chills west of I-55.

- Strong south winds will develop Tuesday, with gusts potentially (20-50% chance) reaching 45 mph. These winds may impact travel for high-profile vehicles.

- Widespread rain is likely (70% chance) Wednesday night into Thursday. Most areas will see rain, but snow or a wintry mix is possible for areas near and north of the I-74 corridor where there is a 20-40% chance for an inch of snow.

DISCUSSION

Issued at 140 PM CST Sun Feb 22 2026

Today and Tonight: Cold and Breezy Conditions A robust 1055+ mb high pressure system remains centered over the Canadian Prairies, with its associated ridging extending south across the Great Plains. Concurrently, a pair of low pressure systems are influencing the pattern to our east: one situated over the Great Lakes and another tracking along the mid-Atlantic Coast. The moderate north/northwesterly pressure gradient established between these features is maintaining breezy and cold conditions across central Illinois today.

Temperatures will only reach highs mainly in the 20s this afternoon before dropping back into the teens overnight. The combination of cold temperatures and persistent wind will lead to sub-zero wind chill values. Based on LREF guidance, a 60-80% chance for sub-zero wind chills exists along and west of I-55, with a 20% chance extending eastward toward the I-57 corridor.

Monday and Tuesday: Transition and Gusty Winds The surface ridge axis will progress across central Illinois on Monday, providing a brief period of lighter winds during the later part of the day. Following the passage of the ridge axis Monday night, a return to southerly flow will spread across the region, marking the beginning of a gradual warming trend. High temperatures are forecast to rebound into the 40s and 50s beginning Tuesday and persisting through the remainder of the work week.

Ahead of the next system, gusty winds are expected across central Illinois on Tuesday. A shortwave digging across the Great Lakes Tuesday and Tuesday night will tighten the pressure gradient sufficiently to produce strong gusts. NBMs 75th percentile peak gust on Tuesday aligns closely with our Wind Advisory criteria of 45 mph. At this time, any precipitation associated with this wave is favored to remain north of the I-74 corridor.

Mid-Week Precipitation Potential Attention turns to the next in a series of shortwaves traversing the region. A wave moving through Wednesday night into Thursday presents the best chance for any meaningful precipitation locally. Confidence is high for a wetting rain, with NBM probability for 0.1" QPF across the area registering between 60-70%.

The primary forecast challenge remains the potential for wintry precipitation. The chance for an inch of accumulating snow is currently 20-40% along and north of the I-74 corridor, decreasing to low but non-zero probabilities (around 10%) south to the I-70 corridor.

Analysis of thermal profiles and forecast soundings from the GFS model suggests that precipitation will primarily fall as rain across the majority of the area. However, a mix including freezing rain and sleet will be possible near the I-74 corridor, with a transition to snow favored further north. The slightly warmer ECMWF solution suggests a more widespread rain event across central Illinois. As is typical several days out, there is still plenty of time for fine-tuning these details regarding precipitation type and placement.

Deubelbeiss

AVIATION

(For the 06z TAFs through 06z Monday Night) Issued at 1030 PM CST Sun Feb 22 2026

Central Illinois falls between high pressure over the Plains and low pressure over the Great Lakes. Moderate northwest flow continues with gusts into the mid 20 kt range expected to continue through early afternoon Monday. The high to our west will bring light/variable winds by evening. MVFR level cold air stratocumulus will be pushing south of the terminals over the next few hours, followed by higher level stratocu with bases around 3500-4000 feet through mid morning. Beyond that mainly SKC for the remainder of the forecast.

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ILX WATCHES/WARNINGS/ADVISORIES

None.