textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Wind chills in the -5 to -15 degree range expected this evening into tonight.

- Light wintry precipitation Friday evening.

- Several potential chances for snow through mid week next week.

UPDATE

Issued 935 PM CST Thu Dec 4 2025

Other than chasing hourly temp trends, no major changes to the prior forecast. Still expecting winds to gradually increase tonight as high pressure drifts east. Winds chills are beginning to dip into the negative single digits and will continue down into the negative teens overnight into early Friday morning.

Wagner

SHORT TERM

Issued 315 PM CST Thu Dec 4 2025

Tonight through Friday night:

The core of the surface high pressure system is passing overhead at the moment, hence the perfectly clear skies and nearly calm wind. As the high weakens and drifts east, southwesterly winds will begin to develop this evening, and with the snow covered grounds and mostly clear skies priming the environment for radiational cooling, wind chills of -5 to -15 are expected to occur this evening through just after midnight tonight. The corresponding air temperatures bottom out in the single digits to around zero. Late tonight, the brute force warm air advection and increasing cloud cover will allow the temperatures to increase a few degrees before sunrise Friday morning. WAA continues into the daytime hours of Friday, with high temps lifting into the 20s.

A clipper system yields a brief period of 20-50% precip chances late Friday afternoon through Friday evening. The associated cold front crosses the region around midnight Friday night, with winds veering northwest and conditions drying out behind it. If applicable at all, this precip would amount to either a dusting of snow or a thin glaze / trace of freezing drizzle (or a wintry mix of both). The uncertainty with the precipitation type is due to the very shallow nature of the moisture in forecast soundings, which may or may not reach the DGZ to form cloud ice.

Sheppard

LONG TERM

Issued 315 PM CST Thu Dec 4 2025

Saturday through Thursday:

To sum up the entire long-term forecast, temperatures remain cool, and occasional clipper systems (fast moving low pressure systems) yield short periods of snow chances.

The passage of a weak surface ridge on Saturday will lead to relatively slow northwest winds and dry weather, with highs remaining in the 20s. The first clipper system arrives Saturday night, delivering snowfall in the ballpark of a dusting to 2 inches. Light snow chances taper off into Sunday morning as the clipper exits. We're expecting a light north breeze and highs in the upper teens to 20s for Sunday afternoon.

Similar clipper systems, some with slightly stronger dynamics, are then expected off and on into the early half of next week. High temperatures remain below freezing, likely making their closest approach to the freezing mark (warmest) on Tuesday or Wednesday before trending back down.

Sheppard

AVIATION

Issued 935 PM CST Thu Dec 4 2025

High pressure will continue to drift east tonight and southwesterly winds will gradually increase. Clouds will increase overnight. While initially looking at VFR ceiling, the swath of MVFR ceilings (1.3-3.5kft) to the west is looking to progress more east and is looking more likely to impact southern WI tonight. Mainly expecting MSN and JVL to see these lower ceilings first but less certain for the terminals further east. Additionally there will be a window LLWS overnight as well with 40-50 knot LLJ working its way overhead.

Breezy southwesterly winds will continue through the morning and early afternoon, but will gradually weaken into the afternoon as a cold front approaches. Then looking at a potential for some light snow and/or mix of freezing drizzle to move through southern WI with the increased chances along and north of I-94. Still uncertain on the extent and coverage of this activity, but could bring some nuisance type impacts into Friday evening.

Wagner

MARINE

Issued 315 PM CST Thu Dec 4 2025

Southwest winds will increase this evening to gale force over the northern half of the lake as an area of low pressure around 29.6 inches moves across southwestern Ontario. A Gale Warning is in effect from late this evening through mid morning Friday. Freezing spray is also expected during this time.

A cold front extending south of the low will cross the lake Friday night. Southwesterly winds remain breezy (25-30 kt gusts) ahead of the cold front Friday, gradually subsiding and veering northwest behind it. Northwest winds gradually decline throughout Saturday then become light and variable Saturday evening as a weak surface ridge of high pressure builds into the region. Stronger high pressure tracking southeastward through the Dakotas and a weak low pressure system tracking eastward past southern Illinois will work together to drive north winds around 20-25 kt on Sunday.

Sheppard

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Gale Warning...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ868 until 9 AM Friday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until midnight Saturday.