textproduct: Milwaukee/Sullivan

KEY MESSAGES

- A Cold Weather Advisory is in effect for all of southern Wisconsin tonight through 10 AM CST Sunday. Expect wind chill values in the negative 25 to locally negative 30 degree range.

- Wind chills will fall into the negative teens Sunday night into Monday, with local areas seeing wind chills as low as negative 20 degrees.

- Above average temperatures develop Tuesday afternoon through Thursday, with highs in the mid to upper 30s.

- The next chances for precipitation (40 to 60 percent) develop Wednesday night into Thursday. With temperatures near to above freezing, much of this precipitation is expected to be rain.

SHORT TERM

Issued 258 PM CST Sat Dec 13 2025

Tonight through Sunday night:

Gusty northwesterly winds will continue throughout tonight as Arctic high pressure builds southward. Temperatures will rapidly fall into the single digits below zero after sunset as skies clear, with areas in central Wisconsin and the Wisconsin River Valley falling into the negative 10 to negative 15 degree range. With winds remaining elevated throughout the overnight hours, expect wind chill values in the negative 20s to locally negative 30 degrees. Negative 30 degrees and below would reach the criteria for Extreme Cold, but currently not enough confidence in winds remaining gusty enough to produce criteria wind chills for long enough to warrant the upgrade. Regardless of exact values, frostbite on exposed skin is possible in as little as 30 minutes overnight tonight. Wear appropriate clothing and check on susceptible people and pets.

As the Arctic high builds into the area fully on Sunday, expecting winds to diminish to light and variable, allowing for wind chills to more closely match the air temperatures. Although air temperatures will remain frigid (slowly warming into the single digits above zero degrees), wind chill values will improve drastically mid-morning as winds diminish. The Cold Weather Advisory is currently in effect through 10 AM CST Sunday. Clear skies are then expected throughout Sunday afternoon with highs in the single digits above zero.

Sunday night, high clouds begin to stream in from the north as high pressure exits to the southeast, allowing for increasing southwesterly winds throughout the overnight hours. Expecting lows around zero degrees, but increasing temperatures during the later overnight hours into the single digits above zero as warmer air pushes northeastward again. The combination of still- quite-cold temperatures and gusty winds will lead to wind chills in the negative teens and a few areas down to negative 20 degrees. Currently localized enough that a Cold Weather Advisory would not be needed for the overnight hours, but will reassess if trends move toward colder temperatures during the period of higher winds.

MH

LONG TERM

Issued 258 PM CST Sat Dec 13 2025

Monday through Saturday:

Another cold and breezy day is expected on Monday, as southerly winds increase behind departing high pressure. Highs will be in the low to mid 20s, with wind chills in the single digits above and below zero.

Steady warm advection will bring warmer temperatures into the region for mid week, with highs Tuesday-Thursday expected to be in the mid to upper 30s. Not much in the way of precipitation is expected until Thursday, when a robust storm system will move through the upper Midwest and Great Lakes. Ensembles are in good agreement in keeping the surface low north of the area (likely tracking across northern Wisconsin and/or Lake Superior). This scenario has southern Wisconsin solidly on the warm side of this system, with rain favored Wednesday night and Thursday, before a cold front sweeps across the region later Thursday.

That front looks to usher in a return to much colder temperatures to end the workweek, though some moderation appears possible heading into the following week.

Boxell

AVIATION

Issued 258 PM CST Sat Dec 13 2025

High clouds between 10,000 and 25,000 ft will slowly exit to the southwest this evening and tonight, with clear skies expected thereafter. Northwesterly winds will gust around 20 kt throughout the overnight hours as well. Winds will diminish slowly through the morning hours Sunday, becoming light and variable during the afternoon hours. High level clouds move back in Sunday afternoon as well. Winds then shift to become southwesterly Sunday night, with gusts up to 25 kt by Monday morning. Overcast skies are expected by Monday morning as well, although VFR ceilings are expected.

MH

MARINE

Issued 258 PM CST Sat Dec 13 2025

Brisk northwest winds and heavy freezing spray will continue across all open waters through Sunday morning as Arctic high pressure slowly builds down through the northern Plains into Iowa and weak low pressure exits through Quebec. In nearshore waters, a Small Craft Advisory remains in effect through Sunday morning, and some heavy freezing spray is possible.

Winds will gradually ease Sunday afternoon and evening as high pressure moves into the Ohio Valley. Low pressure then enters the Hudson Bay as high pressure exits, bringing brisk southwest winds late Sunday night into Monday. A Gale Watch is in effect for this time frame, and Small Craft Advisories will also be needed. A brief period of lighter winds develop Monday night, but low pressure develops and progresses eastward across southern Canada into Tuesday, bringing an additional round of brisk southwest winds and gale potential, especially across the northern half. Winds diminish into Wednesday as low pressure exits, but become gusty and southwesterly again Thursday as an additional low pressure system progresses across the northern Plains.

MH

MKX WATCHES/WARNINGS/ADVISORIES

WI...Cold Weather Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056- WIZ057-WIZ058-WIZ059-WIZ060-WIZ063-WIZ064-WIZ065-WIZ066 until 10 AM Sunday.

Cold Weather Advisory...WIZ062-WIZ067-WIZ068-WIZ069-WIZ070- WIZ071-WIZ072...6 PM Saturday to 10 AM Sunday.

LM...Gale Watch...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM Monday to noon Monday.

Heavy Freezing Spray Warning...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until 9 AM Sunday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until noon Sunday.