textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Light snow will affect central and east central Wisconsin through mid day. Light accumulations up to a half inch are expected. A few flurries will be possible farther south and west.

- A wintry mix of snow, sleet, and freezing rain will impact southern and central Wisconsin Sunday afternoon and evening, with increasing chances for freezing drizzle Sunday night into Monday morning. Impacts to travel Sunday night and Monday morning are looking increasingly possible. - Polar air to remain over southern Wisconsin through the weekend, then relatively mild temperatures move in for next week.

UPDATE

Issued 850 AM CST Sat Jan 3 2026

Light snow will continue through midday across central and east central Wisconsin, associated with a weak shortwave and the left exit region of the jet stream. Despite dry low levels, visibilities across central Wisconsin have been observed in the 1 to 3 mile range. Up to a half inch of accumulation is expected across this area. Farther to the south and west, just a few flurries are anticipated before snow moves east of the region by mid day.

Boxell

SHORT TERM

Issued 409 AM CST Sat Jan 3 2026

Today through Sunday Night:

The mosaic of radars over MN and WI shows light returns over most of the area early this morning, but individual radars have a "donut" around them. The cloud base heights are 6000 ft or higher and surface dewpoints are in the single digits. This all points to dry air in the low levels. The weak mid level shortwave trough tracking across the region is expected to produce a brief period of sufficient lift for the snow in the mid levels to overcome most of the dry air in the low levels during the morning hours today. We are looking at a high pop/low precip event for central and east central WI, meaning snow will be falling out of the sky, but accumulations will be light. Areas south of I-94 may not see any snow today. Snow chances will exit eastern WI just after noon today.

Clear skies are expected tonight, although upstream satellite and subtle low level warm air advection suggest that clouds could linger. Clear skies would allow temps to get into the single digits tonight, but if clouds hang on then lows will be in the teens, similar to last night.

Look for increasing clouds Sunday as broad lift works its way into the area as a mid level shortwave trough approaches from the Northern Plains. By Sunday afternoon, the nose of the low level jet, mid level vorticity advection, and left exit region of the upper jet will all be in place over central WI. The area of associated precip is expected to track across central and portions of southern WI quickly during the afternoon and evening. Looking at forecast soundings, the majority of the precip will be just ahead of the warm front, meaning the column of air would all be below freezing. However, a robust warm nose along the front could push the air aloft above freezing and give us a brief wintry mix of sleet or freezing rain. Areas toward central WI have the best chance of all snow through the evening (during the main period of forcing), while areas south could see a mix of snow and freezing drizzle.

Snowfall amounts up to 1 inch are possible toward Sheboygan, with a dusting south of there. The forecast snow ratios have come down a bit (8:1 now) in east central WI and continue to be lower elsewhere. Surface temperatures are expected to remain below freezing during this whole event, so if we lose ice crystals, then icing on untreated surfaces is a concern for the evening commute for the end of a long holiday weekend.

The shortwave will exit after midnight, but the low level (strong) warm air advection will continue into late Monday morning. This would dry out the mid levels but not the low levels and allow for a period of freezing drizzle. By late Monday morning, temps should be above freezing and end any icing potential. More details are included in the next section.

Cronce

LONG TERM

Issued 409 AM CST Sat Jan 3 2026

Monday through Friday:

Weak ridging aloft and largely dry air within the column will keep the region largely dry later Monday. However, there is some lift and moisture from the WAA at 850mb late Sunday night into early Monday morning. This is primarily a concern for central and east central WI with some freezing drizzle Monday morning possible. In addition, the moist low levels, very cool surface and rapid warming with height may very well bring some freezing fog concerns Monday morning as well. These risks will exit later Monday morning moisture dissipates and we warm up a bit but the morning commute, especially toward central WI may be a bit of a concern.

Weather will then be quiet through most of Monday night with drier air in the column. Freezing fog will again be possible Tuesday morning given the cool surface temperatures, rapid warming aloft and moisture. As we head through Tuesday morning a surface low and associated shortwave aloft will bring some rain chances. Models are still a bit all over the place with the track of this system but it stands to reason that some precip is possible Tuesday morning and into the early afternoon. At onset, any precip would likely be freezing rain as warm air aloft will melt any ice and rapid temps falls near the surface will allow for rain to freeze on contact. This look likely to be temporary as temperatures at the surface will increase through the morning with any precip becoming rain by the late morning and early afternoon. This system will push fully out of the region Tuesday night.

Wednesday into Thursday according to models looks largely dry behind the Tuesday system and the late week system. This is in large part due to drier air aloft and lack of any real forcing.

However, our attention then turns to the late week system which has the potential to be fairly impactful. The issue is there is a ton of uncertainty among models with vast differences in intensity of the system, the track, the timing (both when and how long) and even the impact of temperatures on this system. In any case, models both suggest that the while the onset may be rain the back portion of this system will likely feature some level of accumulating snow. How much, depends on factors mentioned above. But the high end snow accumulation scenario lines up with the ECMWF operational 0z run which shows a very wrapped up upper low moving right over southern WI to which the surface low occludes and slows down and high end snow can fall on the north side of the low which would likely include banding from Fgen.

Kuroski

AVIATION

Issued 850 AM CST Sat Jan 3 2026

Light snow is expected at Sheboygan this morning, with visibility varying between MVFR and IFR. A few flurries/very light snow showers are possible a Madison, Milwaukee, and Waukesha, but little to no accumulation is expected that far south. Snow will end by mid day.

Outside of the snow potential, VFR will prevail. Winds will remain from the west-northwest through the day, becoming light and variable tonight.

Boxell

MARINE

Issued 409 AM CST Sat Jan 3 2026

Modest west northwest winds will prevail through Saturday night as low pressure continues to weaken over Hudson Bay. A ridge of high pressure will also extend from Minnesota into the Ohio Valley during this time. The high will then move across Lake Michigan on Sunday. Breezy southerly winds will then develop Sunday night and linger into Monday morning, as a wave of low pressure moves across the Upper Great Lakes.

Cronce

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...None.