textproduct: Milwaukee/Sullivan

KEY MESSAGES

- A lake effect snow band is forecast to come onshore early Sunday morning into Sunday afternoon. Moderate to brief heavy snowfall rates are possible leading to snowfall of 2 to 5 inches in eastern MKE, Racine and Kenosha Counties, locally more possible. A Winter Weather Advisory is in effect.

- Wind chills between negative 10 and negative 20 degrees are expected tonight into early Sunday morning.

- A Cold Weather Advisory for wind chills of negative 20 to negative 25 degrees will likely be needed Sunday night into Monday morning.

- Wind chills in the negative teens are expected each night Monday through Wednesday.

UPDATE

Issued 949 PM CST Sat Jan 24 2026

Mesolow lake effect features, indicative of very unstable conditions (Lake to 850 mb temp diffs of 22C) within an arctic air mass and light synoptic winds, are prevalent over the wrn half of Lake MI. The mesolows are slowly approaching the shore, but will not come onshore until the early morning hours. They will likely stall and weaken a bit, then transition to a single band later Sunday morning as the 1000-850 mb winds increase out of the northeast due to low pressure developing along the spine of the srn and central Appalachians. Both the anticipated track of the mesolows and transition to a single band warranted expanding the Winter Wx Advisory to MKE County. Forecasting 2-5 inches, locally more, along the far ern portions of MKE, Racine, and Kenosha Counties. Overall expect light to moderate snowfall rates, but brief heavy rates possible.

Gehring

SHORT TERM

Issued 324 PM CST Sat Jan 24 2026

Tonight through Sunday night:

Very light snow is possible along the Wisconsin and Illinois border this evening into tonight as low pressure develops in the Lower Mississippi Valley, with trace accumulations possible in some spots. Expecting lows in the single digits below zero, with wind chills in the negative teens to locally negative 20 degrees.

As low pressure begins to organize late tonight into Sunday morning and high pressure lingers over the western Great Lakes region, expecting convergence over Lake Michigan to strengthen, allowing for a lake effect band (already developed over the central portions of the lake) to become well organized. Water temperatures in Lake Michigan remain in the 1 to 2 degrees C range, with 850 mb temperatures in the -15 to -19 degree range. This leads to a temperature difference of 16 to 21 degrees, which is well within the preferred range for moderate to heavy rates. In addition, the saturated/unstable column is solidly within the dendritic growth zone, increasing potential for high ratio snowfall. With these ingredients in play, rates of 0.5 to 1"/hr are possible within the core of the band.

With all that said, the question becomes whether the core of this band can make its way onshore early Sunday morning. As low pressure ejects into the Southeast U.S. and turns winds over Lake Michigan to northeasterly, high pressure lingers over the western Great Lakes. This will have the dual purpose of keeping the band organized, but also potentially preventing the band from moving inland more than a few miles. 12Z mesoscale runs make a solid case for the convergence zone meandering westward into eastern Racine and Kenosha County, with a few models indicating areas as far north as Milwaukee and as far west as I-94 could see impacts from the band. For now, with confidence increasing, have issued a Winter Weather Advisory for Racine and Kenosha Counties for 2 to 4 inches of snow. Localized areas near Lake Michigan may see up to 6 inches where the band lingers longest.

Low pressure finally departs into the mid-Atlantic Sunday afternoon, and winds will shift back to northwesterly accordingly. This will allow the band to progress back eastward into open waters, with Arctic high pressure moving back in behind the band as it exits.

Outside of the lake effect banding, expect generally cloudy to partly cloudy skies and highs in the single digits above zero. Within the band, expect highs in the positive teens.

Sunday night, with northwesterly winds continuing and an Arctic airmass returning, expect temperatures to drop to around negative 10 degrees inland from Lake Michigan and into the negative single digits near Lake Michigan. Wind chills in the negative 20 to negative 25 range are expected, and a Cold Weather Advisory will likely be needed. Wind chills will gradually improve through Monday morning.

MH

LONG TERM

Issued 324 PM CST Sat Jan 24 2026

Monday through Saturday:

Winds will shift southwesterly ahead of a clipper system traversing northern Wisconsin Monday, bringing highs around positive ten degrees. A few snow showers are possible across central Wisconsin (15 to 20 percent chance). A cold front from this system will progress through southern Wisconsin Monday night, bringing gusty northwest winds and windchills in the negative teens (lows in the single digits). Northwesterly flow continues through at least midweek, with windchill values in the negative teens each night through Wednesday. Wednesday night into Thursday, the next clipper system approaches, with this one projected to impact central Illinois. A few snow showers are possible across southern Wisconsin (15 to 20 percent chances) Wednesday afternoon through Wednesday night. Arctic high pressure building in Thursday through Friday will bring light winds and therefore improving wind chills through the end of the week. High pressure slides eastward with a return to more seasonable highs in the teens to low 20s Friday and Saturday.

MH

AVIATION

Issued 949 PM CST Sat Jan 24 2026

MVFR Cigs will develop over far sern WI early Sun AM and last into the afternoon as lake effect snow affects the region. Vsbys of 1-2SM with the snow, periodically down to 1/2SM to 3/4SM. Elsewhere across srn WI, VFR conditions are expected but cloud bases may lower to 3.5-6.0 kft.

Gehring

MARINE

Issued 949 PM CST Sat Jan 24 2026

High pressure of 30.5 inches will shift into the northern Great Lakes tonight into Sunday morning, while a trough of low pressure extends from north to south across Lake Michigan but moving toward the western shore. Light to modest southeast winds will prevail on the east side of the trough with northwest winds on the west side of the trough. Lake effect snow will be prevalent along this wind shift.

A dominant low pressure area will then develop offshore the Mid Atlantic States for Sunday afternoon and night, which will shift the winds to brisk northerly for all of Lake Michigan, shifting to northwest late Sunday night and Monday morning. Brisk west to southwest winds are then forecast Monday afternoon and night before another arctic front shifts the winds back to northwesterly for Tuesday. A Heavy Freezing Spray Warning is in effect for Sunday night through Tuesday.

Gehring

MKX WATCHES/WARNINGS/ADVISORIES

WI...Winter Weather Advisory...WIZ072...6 AM Sunday to 3 PM Sunday.

Winter Weather Advisory...WIZ066-WIZ071 until 3 PM Sunday.

LM...Heavy Freezing Spray Warning...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876- LMZ878...6 PM Sunday to 6 PM Tuesday.

Small Craft Advisory...LMZ645-LMZ646...9 AM Sunday to noon Monday.