textproduct: Chicago

KEY MESSAGES

- Scattered snow showers and areas of blowing snow this morning.

- Bitterly cold conditions this morning with wind chills 20 below to 25 below zero. Then continued very cold through Tuesday morning.

- A clipper system is expected to bring accumulating snow to parts of the area Tuesday night into Wednesday morning, especially for areas north of I-80.

- Two cold fronts, Wednesday night and Thursday night, may each bring a period of light snow or snow showers.

- Another period of bitterly cold temperatures is possible Thursday night into this weekend.

DISCUSSION

Issued at 300 AM CST Mon Jan 19 2026

The arctic front has pushed through the cwa and with its arrival were heavy snow showers with continued scattered snow showers across parts of the Chicago metro area. While these are expected to continue to slowly shift southeast and weaken through daybreak, upstream obs show many locations reporting 2-5sm vis with snow showers/flurries and likely continued blowing snow. Planning to have scattered snow showers and areas of blowing snow this morning and with flurries possibly continuing all day. Northwest winds gusting as high as 40 mph through daybreak will begin to slowly diminish later this morning into this afternoon.

Current precip and cloud cover has slowed the temp drop slightly early this morning but expected low temps in the low single digits for much of the area, a few degrees below zero across the northwest cwa still appear on track, with the low temps perhaps occurring after sunrise. Combined with the winds, wind chills in the 20 below to 25 below zero range still on track and no changes planned to the cold weather advisory. High temps today will struggle back into the mid/upper single digits, perhaps low teens across the south. Wind chills will remain below zero through Tuesday morning. Similar low temps are expected Tuesday morning, low single digits, near zero in the northwest cwa, but with much lower winds, wind chills Tuesday morning look to be in the 5 below to 10 below zero range.

There is another weak wave moving across the area this evening that the models remain dry with. Expect an increase in cloud cover and there is the potential for some flurries, maybe a few snow showers with this wave, but confidence too low to include mention at this time. A fast moving area of high pressure will then cross the area Tuesday morning.

The models have remained in overall good agreement with a clipper moving across the region Tuesday night into Wednesday morning. Though the most recent trend is for this system to arrive sooner with snow spreading across northwest IL Tuesday evening and then across much of northern IL, north of I-80 after midnight. Blended guidance has increased considerably, now well into the 80% range and qpf is now trending in the 0.10 to 0.15 range across far northern IL. As a result, a swath of 2-3 inches is possible near the IL/WI state line with amounts lowering further south with perhaps a rather sharp cutoff to the southern edge of the snow. While most of the falling snow could be done by the Wednesday morning rush hour, untreated roads will likely be snow covered for the commute.

A cold front is then expected to move across the area Wednesday evening, possibly into early Thursday morning. While not as strong as the cold front this morning, there could be another period of light snow or snow showers associated with this cold front. In between the clipper Tuesday night and this cold front Wednesday night, high temps Wednesday may briefly moderate in the upper 20s north to possibly lower/mid 30s south.

The models and their ensembles have taken a turn to much colder and drier for late week into this weekend. Still several days away but the arctic high pressure building across the northern Plains and Great Lakes region Thursday night into Friday may send another strong arctic cold front across the area Thursday afternoon or Thursday evening and another period of snow or snow showers would be possible if this materializes.

Blended guidance is now significantly colder for Thursday night into Saturday with subzero lows areawide Saturday morning with wind chills in the 20 below to 30 below zero range. While there is increasing confidence for this, confidence is still low for these specifics and there is still quite a bit of uncertainty for this weekend into early next week. cms

AVIATION /12Z TAFS THROUGH 18Z TUESDAY/

Issued at 600 AM CST Mon Jan 19 2026

- Strong WNW winds this morning gusting to 30+ kt leading to continued blowing and drifting snow

- Scattered light snow showers early this morning with flurries lingering through midday (possibly much later)

While tough to see on radar, there are narrow northwest to southeast oriented bands of MVFR clouds that are producing light snow showers which may move over the terminals intermittently through mid morning and produce an additional dusting of fluffy snow.

Winds remain strong out of the west northwest with gusts to 30+ kt expected through the morning. This will lead to continued blowing and drifting snow with associated VSBY reductions which combined with any snow showers may drop to low-end MVFR to briefly IFR. Flurries may then persist through at least midday. Based on upstream observations wouldn't be surprised if flurries continue through the rest of the day into this evening but confidence was not high enough to include with this update in the event that MVFR clouds manage to scatter out.

Winds are expected to ease with sunset and turn west southwesterly through the night.

Petr

MARINE

Issued at 418 AM CST Mon Jan 19 2026

No changes to the gale warning or heavy freezing spray warning.

Gale force winds have been slow to arrive across portions of the IL nearshore waters early this morning, but a period of gale force winds is still expected, which will then diminish to 30 kt this afternoon. Gales across the IN nearshore waters will slowly diminish through the afternoon and to 30 kt mid/late afternoon. The strong winds combined with the high waves will allow for freezing spray, which is expected to be heavy across portions of the IN nearshore waters, mainly east of Gary, IN. This heavy freezing spray potential will persist into this evening with winds to 30 kt still expected. cms

HYDROLOGY

Issued at 126 PM CST Sun Jan 18 2026

Area hydrographs and ice spotter reports confirm that ice continues to develop and spread across areal rivers. Localized ice jams are already present along the Rock and Des Plaines rivers. Continued cold temperatures tonight and Tuesday will cause ice to continue growing.

After a brief warm-up in temperatures to above 20 degrees on Wednesday, another push of bitterly cold temperatures may arrive as early as Friday. As a result, the threat for ice jams including localized flooding will increase further toward the end of the week.

- NWS Chicago

LOT WATCHES/WARNINGS/ADVISORIES

IL...Cold Weather Advisory until noon CST today for ILZ003-ILZ004- ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-ILZ019- ILZ020-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039-ILZ103-ILZ104- ILZ105-ILZ106-ILZ107-ILZ108.

IN...Cold Weather Advisory until noon CST /1 PM EST/ today for INZ001-INZ002-INZ010-INZ011-INZ019.

LM...Gale Warning until noon CST today for Winthrop Harbor IL to Gary IN.

Gale Warning until 3 PM CST this afternoon for Gary to Burns Harbor IN-Burns Harbor to Michigan City IN.

Heavy Freezing Spray Warning until 9 PM CST this evening for Gary to Burns Harbor IN-Burns Harbor to Michigan City IN.