textproduct: Chicago

KEY MESSAGES

- Light accumulating snow possible (50-70%) Tuesday afternoon/evening and again Wednesday afternoon/evening.

DISCUSSION

Issued at 231 PM CST Mon Dec 29 2025

Very light snow/flurries have continued into this afternoon. A dusting of new snow accumulation is possible in some areas but with the continued gusty winds, areas of blowing snow will remain possible this afternoon. Winds will be slowly diminishing through this evening with gusts ending by late evening or early overnight.

Some breaks in the clouds have developed today and the cloud cover upstream is looking rather thin with continued breaks in the clouds. Much of the guidance suggests this low cloud cover will be scattering out overnight and perhaps be exiting the cwa by daybreak. Have trended a bit more optimistic for cloud trends tonight. Prior to any possible scattering, there will likely be a continued chance of flurries this evening and added mention to the forecast.

Attention then turns to two weak clipper systems. The first to arrive Tuesday afternoon. This system has been in the models for several days, but has slowly been trending further south and much of the latest guidance now has light snow spreading/ developing across northern IL Tuesday afternoon and then ending early Tuesday evening, mainly falling during the evening rush hour. While confidence is only medium given the change in trends, this looks to be a high pop/low qpf event and opted to increase pops to likely. But snowfall amounts may only be a dusting to a half inch or so, mainly along/north of I-80.

A second clipper system will move across the area Wednesday afternoon into Wednesday evening. There has been a bit better consistency between the models with this system (compared to the Tuesday clipper). This also appears to be another high pop/low qpf event and increased pops to likely. Timing also looks to be during the Wednesday afternoon/evening rush hour. Snowfall amounts may be more toward the one inch range. The snow looks to end Wednesday evening and then another push of colder air is expected into Thursday with wind chills Thursday morning perhaps in the -5 to +5 range.

Temps look to moderate into the weekend, with perhaps temps getting a little above normal. Blended guidance is mainly dry which looks on track from this distance, but there does appear to be another weak wave to move across the area Saturday night or Sunday that could bring a brief period precip chances back to the area. cms

AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 1107 PM CST Mon Dec 29 2025

Key Aviation Messages for the current TAF period:

- Period of IFR snow late afternoon/evening tomorrow

Mid-high level cloudiness will quickly increase Tuesday morning in advance of the next fast moving weather system expected to impact the area tomorrow. Confidence in a period of light snow has increased enough to go with a period of prevailing IFR snow very late afternoon into the early-mid evening. Snow is expected to end by mid-late evening with MVFR CIGS likely to through the remainder of the night.

- Izzi

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...Small Craft Advisory until 3 AM CST Tuesday for the IL nearshore waters.

Small Craft Advisory until 3 PM CST Tuesday for the IN nearshore waters.