textproduct: Chicago

KEY MESSAGES

- A relatively quiet pattern will continue through the weekend with a few snow showers today near the Wisconsin state line, and near the Lake Michigan shoreline tonight into Sunday.

- A period of warmer, and wetter, conditions is expected next week into the second full week of March.

DISCUSSION

Issued at 129 PM CST Sat Feb 28 2026

Through Sunday Night:

It's a rather banal day across the region with broken upper- level cloud cover and northeasterly winds. A band of snow continues to meander across southeastern Minnesota and southern Wisconsin, with dry air largely limiting any meaningful southward penetration into northern Illinois. Temperatures across the area vary from north to south, ranging from near freezing along the Wisconsin state line to around 50 near US-24.

Tonight, a 1035mb surface high will build into the Upper Great Lakes and support an increase in northeasterly flow and cold air advection down Lake Michigan. In spite of marginal inversion heights (a consequence of the cyclonic shear axis of the upper- level flow remaining well northeast of our area), increasing shoreline convergence should support a gradual increase in lake- induced stratus, flurries, and a few show showers. In all, this set-up looks pretty darn marginal, so will only advertise a dusting to perhaps a few tenths of an inch of snow accumulations should bonafide snow showers actually develop. Elsewhere, tonight will be relatively chilly with overnight lows in the upper teens (northwest) to mid 20s (southeast).

Lake effect flurries and snow showers may continue near the Lake Michgian shore through Sunday morning before tapering in coverage during the afternoon as the surface high meanders through the central Great Lakes. Partly cloudy skies and continued northeasterly winds will otherwise define an unremarkable day with highs generally in the 30s.

Tomorrow night looks similarly quiet with light easterly flow, broken cloud cover, and overnight lows generally in the upper teens to lower 20s. With the baroclinic zone expected to stall across southern Missouri, Illinois, and Indiana, any precipitation with the next wave propagating into the Mississippi River Valley should miss our area.

Borchardt

Monday Onward:

A broader zonal flow regime with an embedded slow-moving trough over the central Rockies early in the week will transition to a much more meridional pattern highlighted by deep western troughing for the second half of the week. Meanwhile, an expansive Bermuda High will foster a persistent feed of Gulf and Caribbean moisture toward the central CONUS through the period. This will ultimately result in a seasonably mild to unseasonably warm period with several rounds of rain and localized convection over the area. While axes of heavy rain appear likely over the mid-Mississippi and Ohio River valleys, it remains to be seen where those axes set-up and whether those axes align over the same location and result in flooding concerns.

Initially, broad low-level isentropic ascent combined with modest moisture transport will bring the first area of precip over the area late Monday night into Tuesday. While rain is favored, low-level wet-bulb temps near freezing could result in minor impacts from light freezing rain close to the Wisconsin state line through mid-morning.

Beyond Tuesday, the spread in the ensemble suite, owing to the differences in the evolution of the western trough, offers less confidence on exactly when and where heavy rain axes develop. However, with PWATs around 1.5" (300% of normal), any pronounced wave emanating from the western trough will induce sufficient forcing to realize focused axes of heavy rain. As a whole, the best focus mid to late week remains just south of the forecast area Tuesday night.

Will also need to keep an eye on the potential for more organized convection in or around the area late Thursday and especially Friday as a large portion of the western trough ejects toward the mid to upper-Mississippi River Valley.

Kluber

AVIATION /06Z TAFS THROUGH 12Z MONDAY/

Issued at 1056 PM CST Sat Feb 28 2026

Breezy northeasterly winds will continue through Sunday morning but the strongest gusts will continue to gradually ease through tonight. MVFR cigs will prevail tonight, although there is some indication cigs may lift to VFR periodically tonight into Sunday morning. At RFD, VFR will likely return overnight tonight. Given the continued flow off the lake, have maintained MVFR at the Chicago-area terminals through midday Sunday, but adjustments may be needed. VFR conditions are expected Sunday night with winds gradually turning southeasterly.

Carlaw

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...Small Craft Advisory until 3 PM CST Sunday for the IL and IN nearshore waters.