textproduct: Central Illinois

KEY MESSAGES

- Patchy freezing drizzle is possible near and north of the I-74 corridor through early morning, which could result in isolated slick spots during the morning commute.

- Another round of snow is possible late Monday night into Tuesday (20-50% chance, highest south of I-72). In most areas, any accumulations will be minor (less than 1") but there could be a narrow band that produces a few inches of snow somewhere south of a Jacksonville to Paris line.

- Temperatures will be less cold this week and through the weekend, with highs generally in the 20s and 30s. A more noticeable warm-up is possible next week (40-50% chance).

DISCUSSION

Issued at 230 AM CST Mon Feb 2 2026

*** TODAY ***

The primary concern through early this morning is the potential for patchy freezing drizzle, mainly near/north of I-74. Had noted a few days ago that forecast soundings suggested a loss of cloud ice as our Sunday snow event came to an end, and it appears that has come to fruition. Regional radar imagery shows areas of very weak returns ahead of a front that is approaching from the northwest. Ceilings were generally above 2500 feet earlier Sun evening, which is high for drizzle to reach the sfc, and HRRR forecast soundings showed a shallow layer of dry low-level air that would mitigate the drizzle potential. However, ceilings have trended steadily lower at Galesburg (KGBG), with the 08z/2am observation reporting 800 foot ceilings. Have not seen sfc observations report DZ or UP south of I- 80, and have not received any reports of surfaces become slick locally, so have held off on issuing a Special Weather Statement at this time. I don't feel strongly that we'll see any freezing drizzle, but felt the situation warranted at least a mention of patchy freezing drizzle in the gridded forecast (near/north of I- 74). The drizzle potential will end as the front moves through and swings winds around to northwesterly. Based on the projected timing of the front, this means the freezing drizzle concerns could linger into the morning commute for locations like Champaign-Urbana and Danville. Be on the lookout for sneaky slick spots.

Once that front moves through this morning, central IL will be situated near the saddle point between surrounding sfc highs/lows. Winds stay northwesterly, but will be relatively light (generally around or less than 10 mph). Skies stay mostly cloudy, with highs near freezing.

*** TONIGHT - TUESDAY ***

A shortwave located over Montana early Monday morning will provide another chance for snow to the ILX CWA late tonight into Tues. Models highlight a swath of light snow across IA/north- central IL overnight as the wave digs toward the area. Introduced some slight chance (20%) PoPs near/north of I-74 to account for this. Within this swath, only a few tenths of snow accumulation are forecast.

The more challenging aspect of the forecast still revolves around the sfc low that tracks south of the I-70 (Missouri) and I-64 (Illinois) corridors on Tues. Exactly how far north and west precip extends remains a point of uncertainty, with some models showing no precip in the ILX CWA and others depicting a banded snow event. The 00z NAM was the most bullish, with forecast cross sections still depicting a crosshair signature (strong ascent within the dendritic growth zone) which leads to a narrow stripe of 2-3" of snow. This east-west oriented band could form as far northwest as Jacksonville, although its worth noting the 00z NAM is a significant outlier compared to the rest of the deterministic guidance.

The uncertainties around the placement of this potential narrow snow band make it a challenging system to effectively message. Made adjustments to the forecast to start increasing PoPs and QPF, but our gridded forecast still calls for less than 1" of snow area- wide. The probabilistic NBM has just a 20-40% chance for over 1" of snow in areas from Mattoon-to- Paris and southeastward, quickly increasing to over 50% in south- central IN. Do not be surprised if the are seemingly drastic adjustments to the forecast between now and its arrival. There is still icy precip potential with this system, but that potential has consistently been focused just south of the ILX CWA, and snow should be the primary p-type in our area. Any precip should exit by 00z Wed/6pm Tues.

*** WEDNESDAY AND BEYOND ***

A weak sfc high will be present Tue night and Wed night. Cloud cover will play a substantial role on the low temps those nights. For now, guidance suggests more cloud cover south of I-70 Tues night, keeping lows in the teens, while north of I-70 lows fall to near 10 degF. On Wed night, clouds are more likely across west- central IL in response to low-level WAA associated with a clipper developing well to the north. This again results in a forecast of lows in the teens in the cloud covered areas (west of I-55), and lows in the single digits in the (mostly) clear sky areas (east of I-55).

Mostly dry conditions are favored through the weekend. That aforementioned clipper is still on track to move through the upper Midwest late in the week, but it should track far enough north to keep precip just north of the ILX CWA. As southerly flow picks up ahead of this wave, highs on Thurs could reach the upper 30s across west-central IL (cooler to the east). The NBM has highs climbing to near 40 on Fri, although with a strong, dry cold frontal passage during the day Fri I do start to question whether we might have non- diurnal temperature trends on Fri. Either way, the winds on Thurs/Fri will be strong enough that wind chill values struggle to rise above freezing, so it won't exactly be a robust warm up.

Following the Fri frontal passage, a cooler air mass (not extreme cold) moves in for Sat. A more appreciable warm-up appears possible into next week, with CPC highlighting a 40-50% chance of above normal temps. Normal temps for that week of Feb feature highs in the upper 30s and lows near 20. The NBM indicates a 30-50% chance of highs above 50 each day Mon-Thurs (Feb 9-12).

Erwin

AVIATION

(For the 12z TAFs through 12z Tuesday Morning) Issued at 504 AM CST Mon Feb 2 2026

Much of the region is blanketed with MVFR ceilings to start the period. A weak front will shift winds from SW to NW this morning. This wind shift has already occurred at KPIA as of 11z. The main challenge is pinpointing when ceilings return to VFR. Aired on the pessimistic side of guidance, but could see the improvement occur sooner than what is in the TAF. NW winds continue through the afternoon until winds become light and variable during the evening/overnight. The potential for light snow returns late in the period, along with the potential for low MVFR ceilings at KSPI/KDEC. Did not have enough confidence to include either of these features in the TAF at this time.

Erwin

ILX WATCHES/WARNINGS/ADVISORIES

None.