textproduct: Chicago

KEY MESSAGES

- Quick shot of snow possible late tonight over far NE IL and NW IN.

- Milder temperatures expected for much of the upcoming work week.

DISCUSSION

Issued at 229 PM CST Sat Feb 7 2026

Mid-level cloud cover will continue to increase across the area into this evening in association with our next quickly approaching low amplitude shortwave impulse riding the northwest flow into the region tonight. While much of the area will see cloud cover around tonight, we do continue to monitor the potential for a quick hit of light accumulating snow late tonight across a small portion of the area. It is important to note that most areas will not see any snow as a result of this impulse tonight, owing to the very dry low-level airmass in place. Instead, we are watching areas generally along a narrow north-northwest to south- southeast oriented corridor that extends from southeastern WI and far northeastern IL (especially in close proximity to Lake Michigan) southeastward into parts of northwestern IN. Forecast guidance continues to insist that top-down saturation will occur in this corridor and support a short period (2-4 hours) of snow later tonight. This certainly seems plausible since this is also the general region in which a transient band of frontogenesis is favored to develop and support some enhanced forced ascent. We have thus continued to confine chance to low end likely POPs (30-60% chance) in this general area overnight. The short duration of snow should result in light amounts of a coating to perhaps locally up to an inch.

A large scale weather pattern change is slated to take place into the first portion of the upcoming work week. This will occur as the persistent high amplitude ridging over western North America begins to deamplify and transition the upper-level pattern across most of the country into a more quasi-zonal flow pattern (west-to-east) for a period next week. Overall, this will set the stage for a milder airmass across our region this week as the very cold airmass remains north of the area.

The threat of precipitation also looks to remain low (<20%) across our area through at least mid-week, owing to expectation of weather systems tracking well north and south of our area. Our mildest period this week looks to be Monday into Tuesday, when high temperatures look to tag 40 degrees in most areas. A weak cold front is expected to drop southward across the area on Tuesday. This should bring cooler (highs in the 30s) more seasonable weather back into the region for the remainder of the week.

There remains a lot of uncertainty with a potential late week system. Didn't make any changes to the pops offered up by the NBM, but there continues to be some signal for precipitation potential late in the week, particularly from EPS members.

KJB

AVIATION /18Z TAFS THROUGH 00Z MONDAY/

Issued at 1121 AM CST Sat Feb 7 2026

Key messages for the 18Z TAF period:

* A chance for VFR snow showers and flurries tonight at Chicagoland sites

Near-northerly winds at under 10 kt are veering to NE heading into the afternoon. They'll continue to veer to a ESE by this evening and remain as such through the end of the period. Expect 10 to 12 kt with gusts as high as 20 kt for Sunday late morning and afternoon.

A push of light snow showers will clip extreme NE IL and into NW IN tonight. While the more impactful coverage is favored east of the terminals and out over the lake, some VFR snow showers or flurries may find their way over the Chicagoland sites. In the TAFs, maintained a PROB30 for this potential owing to the possibility that coverage stays out of reach. Time window for this potential is roughly 05Z through 09Z.

Doom

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...None.