textproduct: Chicago

KEY MESSAGES

- Still expecting scattered mainly non-accumulating snow showers and flurries near the lake into the early evening. Lake effect snow showers are possible into parts of northwest IN later tonight-Saturday, mainly northeast Porter Co. and points east.

- Solidly below normal temperatures will return tonight through Saturday, moderating to closer to normal on Sunday.

- Milder conditions are in store next workweek, especially early, though the pattern doesn't currently appear favorable for any significant moisture laden storm systems.

DISCUSSION

Issued at 244 PM CST Fri Feb 6 2026

Through Saturday:

A secondary cold front was moving southward across northern Illinois as of early afternoon, with much stronger cold air advection in the wake of this front through tonight, bringing a period of blustery north-northwest winds through this evening.

In the near term, through early evening, still expecting marginal snow showers near the lake as an zone of lake aided/induced convergence sets up just inland of the lake into early evening. Initial scattered snow showers into far northwest Indiana should also shift into areas near the lake in northeast Illinois and then spread inland near/east of I-57 this evening before dissipating.

Forecast soundings only show cloud tops as cold as -13 to -14C, which continues to suggest that most of the saturation and steeper lapse rates will reside below the favored -12 to -18C DGZ. With temperatures as of this writing well above freezing and then falling to near to slightly below freezing after sunset, the snow showers should be primarily a periodic reduced visibility (down to 2-4 miles at times in any heavier bursts) issue. This can be colloquially called "white rain", as little to no snow accumulations of note are anticipated.

Beyond the early evening snow showers near the lake, the main story will be the abrupt return to cold conditions overnight. Lows by early Saturday will dip into the high positive single digits and lower teens (mid teens near lake in NW IN). Winds will thankfully be diminishing, but nonetheless, minimum wind chills near to slightly below zero are forecast. Lake effect snow showers will redevelop over southeastern Lake Michigan late this evening and then gradually push towards northeastern Porter County into early Saturday. Forecast inversion heights are quite marginal at 5kft or less, limiting the intensity of the lake effect snow showers. It appears the focus overnight into Saturday morning should be into LaPorte County, though generally light snow may still be able to sneak into northeast Porter before the activity shifts east Saturday afternoon. If any light accumulations occur, temperatures will be cold enough for snow to coat roads and cause some impacts (20-30% chance in northeaster Porter Co.).

Aside from the lower end lake effect snow potential, Saturday will be quiet and chilly with highs in the 21-28F range, versus normal values in the lower to mid 30s for February 7th.

Saturday Night through Friday:

A fast moving clipper system and its associated snow chances may brush by just to our north and east Saturday night-early Sunday, with otherwise not as cold conditions as tonight-early Saturday. Into next week, mid-upper ridging in the western CONUS that has been semi-permanent this winter (and brought relentless northwest flow into our region) will finally slide east. The result will be a substantial warm-up locally Monday into Tuesday following near seasonable conditions on Sunday.

A predominant broad western troughing and eastern/southeastern CONUS ridging regime is often unseasonably mild in the cool season, and generally near to above normal precipitation wise. Completely frozen ground and extensive thick river ice into such a stretch would be potentially problematic. However, upstream high latitude blocking centered northeast of Hudson Bay (a west based negative North Atlantic Oscillation/-NAO) should tend to suppress mid- level heights and the lower to mid-level baroclinic zone southward to an extent. This may very well preclude any meaningful precipitation until later in the week. As it stands, the blended guidance held onto some chance for rain Tuesday night into early Wednesday, which should diminish in subsequent updates if recent ensemble trends hold.

A weak cold front will push southward on Tuesday, resulting in a modest cool-down on Wednesday. In a change from previous forecast cycles, the ECMWF ensemble system (EPS) jumped towards a neutrally tilted wave interacting with the baroclinic zone over the region Thursday-Thursday night. If this scenario materializes, that would be our next period to watch for wintry precip in the area as expansive cool, dry high pressure to our northeast would bring lower wet bulb temperatures (and cooler overall thermal profiles). While the signal on the EPS (50-60% of members) can't be ignored, it's the decided minority with respect to the overall multi-model ensemble and as such, our forecast PoPs are only about 20% during that timeframe.

Castro

AVIATION /06Z TAFS THROUGH 12Z SUNDAY/

Issued at 1057 PM CST Fri Feb 6 2026

Key Messages for 06Z TAFs:

- Blustery north winds gusting 20-25 kt gradually diminish overnight, becoming light and variable by early Saturday afternoon and light southeast Saturday night.

- Low probability (<25%) for a 3-4 hour period of light snow toward/after midnight Saturday night.

Blustery northerly winds will persist into the overnight hours in the wake of a cold front. Gusts 20-25 kt will gradually diminish predawn, with winds remaining north-northwest Saturday morning. Surface high pressure will spread across the area during the midday/afternoon hours, which will result in a few hour period of light and somewhat variable winds, which should become light east-southeast by Saturday evening and increase into the 5-10 kt range overnight.

Lingering VFR lake-induced stratocu will persist mainly at GYY overnight and into Saturday morning. Otherwise, mainly clear skies are expected until Saturday afternoon when increasing VFR high clouds develop and eventually thicken and lower into a mid-deck Saturday evening. Low-levels will remain quite dry across the region Saturday night, though there remains a signal for light snow to develop near but mainly north/northeast of the terminals Saturday night. A small subset of model runs do depict development over the area however, though while this can't be completely disregarded the current potential (<25%) is not high enough to include in TAFs at this time. If it were to occur, timing looks to be after about 03Z at RFD and after 05Z for Chicago sites.

Ratzer

LOT WATCHES/WARNINGS/ADVISORIES

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

Gale Warning until midnight CST tonight for the IN nearshore waters.