textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Blustery and cold conditions are expected tonight, with wind chills falling below zero later tonight into Sunday morning.

- Chances (about 20 to 40 percent) for light snow later Sunday night into Monday morning, mainly north of the Interstate 94 and Highway 18 corridor. Any snow accumulations may remain north of the area.

- Temperatures continue to trend well above normal Tuesday through Christmas Day.

UPDATE

Issued 823 PM CST Sat Dec 20 2025

Winds are at or just past peak speeds this evening, and will remain gusty through midnight, before gradually easing heading into tomorrow morning. Clear and cold conditions are expected overnight, with temperatures falling into the mid to upper single digits in most locations.

Boxell

SHORT TERM

Issued 247 PM CST Sat Dec 20 2025

Tonight through Monday:

The cold front will push to the east of the area by sunset, with clear skies and gusty west to northwest winds behind it. This will bring in cold air advection and falling temperatures, which will continue into tonight. Lows tonight should bottom out in the single digits above zero, with wind chills later tonight and Sunday morning in the single digits below zero to around 10 below zero. The coldest values will be in the northern parts of the area.

High pressure passing by to the southwest of the area later tonight into Sunday should bring dry conditions, clear skies and gradually weakening winds. Highs Sunday will be in the lower to middle 20s.

Warm air advection will develop Sunday night into Monday, as winds begin to increase out of the south. Forecast soundings are showing saturation developing above 800 mb later Sunday night into Monday morning, but remaining quite dry below it. A band of 850 mb to 700 mb frontogenesis response shifts northeast through the area during this period, though the best upward vertical motion appears to be more in central and northern Wisconsin.

For now, kept the general 20 to 40 percent chances for light snow in northern portions of the area, though it may trend more to the north per ensemble output of measurable and greater than or equal to 0.10 inches of QPF. It appears most of the snow accumulations may remain to the north as well.

There may be some lingering low level moisture Monday afternoon within weak warm air advection and lighter south winds. The layer above the low levels dries out, so there may be some ice crystal loss and possible drizzle (or freezing drizzle if surface temperatures drop to or below freezing).

As of now, it appears temperatures should remain above freezing. Kept small chances for light snow and light rain for now in the afternoon in northeast parts of the area. May need to add in some drizzle in later forecasts. Highs should rise into the middle to upper 30s Monday afternoon.

Wood

LONG TERM

Issued 247 PM CST Sat Dec 20 2025

Monday night through Saturday:

Some light drizzle may linger into Monday night, as weak warm air advection and low level moisture lingers.

A general ridge axis at 500 mb should build over the Northern Plains into the Upper Midwest Monday night into Christmas Day. Ensembles suggest that this trend will favor well above normal temperatures to work into the region Tuesday into Christmas Day, with Christmas Day the warmest. Highs may reach to near or above 50 degrees toward the Wisconsin/Illinois border on Christmas Day.

There are some hints at a low pressure system moving northeast through southern Wisconsin or northern Illinois later on Christmas Day. Any precipitation looks to be rain at this point with the warm temperatures. Cooler but still above normal temperatures should linger Friday into next weekend.

Wood

AVIATION

Issued 823 PM CST Sat Dec 20 2025

VFR conditions are expected through tomorrow afternoon. Winds will remain gusty out of the northwest tonight, with speeds decreasing heading into the morning hours on Sunday. Winds will become southwesterly by Sunday afternoon.

Boxell

MARINE

Issued 247 PM CST Sat Dec 20 2025

Low pressure of 29.3 inches will continue across Ontario tonight. The associated cold front will cross Lake Michigan from northwest to southeast through early evening. Gusty southwest winds will veer west-northwest by late evening. Widespread gales up to 40 kt with a few gusts up to 45 kt are expected during the evening hours in the wake of the front. Moderate freezing spray is anticipated as Arctic air settles in, with pockets of heavy freezing spray possible.

The Gale Warning goes into effect at 3 PM this afternoon for the nearshore areas of southeast WI. This is a little early, but the wind gusts will ramp up quickly between now and 6 PM this evening. Gale gusts may end prior to the 3 AM Sunday end time of the warning, and it looks like gusts will quickly fall below 25 kt by 6 AM Sunday.

Winds will steadily diminish Sunday, as 30.5 inch high pressure slides across Illinois and Indiana. Low pressure of 29.8 inches will develop over the Great Plains on Monday and track across the Upper Great Lakes Monday night. Southwest winds with 30 knot gusts are possible during the day Monday, though gale potential is low at this time. Winds will weaken Tuesday through Wednesday, as the next area of high pressure of 30.4 inches crosses the Great Lakes.

Cronce

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Gale Warning...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ643-LMZ644-LMZ645-LMZ646-LMZ669-LMZ671- LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874- LMZ876-LMZ878 until 3 AM Sunday.