textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Light snow & freezing drizzle possible (~15-25% chances) along/ahead of a cold front Saturday.

- Light rain & snow possible (~15-25% chances) north of I-94 & US-18 Monday through Monday night.

- Temperatures trending well above normal Tuesday through Christmas Day.

UPDATE

Issued 1038 AM CST Fri Dec 19 2025

Forecast details remain on track this morning. Winds are slowly easing from west to east this morning as a surface ridge builds into the area. Gusts to 30 mph are lingering along the lakeshore, but obs from Madison westward are showing a sharp drop in gusts with westward extent from around 20mph to 10mph. With the easing winds, expect wind chills to improve a bit this afternoon. However, conditions will still be chilly with air temperatures in the upper teens.

CMiller

SHORT TERM

Issued 350 AM CST Fri Dec 19 2025

Today through Saturday:

Synopsis/Mesoanalysis: Surface observations place an area of low pressure along the Ontario-Quebec border this morning. Positioned along the back side of the low, blustery northwest winds continue across southern Wisconsin, advecting Arctic air into the area. Light flurries & snow showers continue in the vicinity of an upper trough over the eastern half of the area. The combination of blustery winds and cold air advection will result in a very chilly start to the day today, with wind chills falling into the -5 to -15 range through sunrise. Currently centered over the Northern Plains, a narrow ridge of surface high pressure will cross southern Wisconsin today, allowing winds to taper by the early afternoon hours. The high will push east of the region tonight, allowing for a southerly wind shift and steadily climbing temperatures after midnight. Currently ejecting into the Canadian Prairies, a second upper disturbance and affiliated surface low will move into Ontario tonight, ultimately progressing into Quebec during the day on Saturday. Progression of these features will drag a cold front across southern Wisconsin Saturday morning and afternoon. Light precipitation is possible along the approaching/passing front, potentially beginning as drizzle or freezing drizzle before transitioning to snow. While snow & ice accumulations will remain minor, a few slick spots can't be ruled out on elevated and untreated surfaces Saturday morning & afternoon. Budget a few extra minutes of travel time if planning to be on the roads.

Rest Of Overnight: Blustery conditions continue along the back side of departing low pressure, with low level cold advection allowing single digit & low teen air temps to move into southern Wisconsin before sunrise. The arriving Arctic air will combine with the gusty northwest winds to support chilly wind chills in the -5 to -15 range through daybreak. Bundle up if heading outdoors this morning. Light flurries & snow showers will wrap up after sunrise.

Saturday: Light precipitation is expected along/ahead of an approaching cold front, with the best potential currently anticipated over the eastern part of the area. Given low level warm advection ahead of the front, in addition to a lack of cloud ice in the prefrontal environment, some precip could start as light drizzle or freezing drizzle. Precip will then quickly transition to all snow along/behind the front as frontogenesis & cold advection allow for the return of cloud ice. Snow & ice accumulations are expected to remain light (dusting/glaze or less), though isolated slick spots can't be ruled out on elevated and untreated surfaces. Budget a few extra minutes of travel time if planning to be on the roads Saturday.

Quigley

LONG TERM

Issued 350 AM CST Fri Dec 19 2025

Saturday night through Thursday:

With the weak clipper system of Friday night into Saturday afternoon to the east of the state, high pressure will move into the state and kick off a stretch of roller coaster temperatures. The upper levels have a ridge building in across much of the western and central CONUS. The GFS tends to be a bit more zonal with this ridge for its deterministic run while the CAN and EURO are a bit more amplified. This tracks well with much of the ensemble data especially when you start to look into Sunday and Monday. Model clusters show a monopole distribution, which points to uncertainty in the amplitude of the ridge. The uncertainty will definitely increases further out in time which is why its in the model clusters at 500mb, but the reason for pointing it out is the strength of this ridge will impact the ability of a trough/low to dig south into the Great Lakes for later in the period. More amplification, the less the low digs south and we get scraps/a glancing blow at precip at best. Less amplified ridge could allow more shortwaves through for slight better chances for precip and would allow for a more southern track with the next strong trough Thursday into Friday (12/25-12/26).

There is a small chance for some light rain and snow along WAA Monday, but the track of the shortwave looks to have shifted slightly further north with this run of guidance. This system is largely in the mid levels around 850 mb with the WAA and shortwave as the upper levels will still be under the ridge. The better support for this WAA precip looks to be to our north with the mid level and sfc level low that traverses from the US/Canada border near Montana almost due east. The better DIV is north, the better winds and LLJ are north.... overall the slight chance for precipitation remains but its mainly across our the northern section of our forecast area around 10-20%.

Now the roller coaster temps, there will be a prolonged period with a southerly component to the winds (whether its southwest or due southerly doesn't seem to matter much). This will allow for WAA to persist from early next week into the end of the week. Highs in the 20s on Sunday will give way to for temps to potentially crawl into the 50s by Thursday. Areas along the WI/IL boarder have the best chances for those 50 degree temps, but overall doesn't matter much if your like me and desperately hoping for a white Christmas. For additional context depending on the day, temps in the 50s approach records, a far cry from the normals in the low 30s. If your a cold and snowy person, then we can all look to the CMC Ensembles for hope beyond day 7. For those looking for warmth and rain then the EURO Ensembles are your friend.

Patterson

AVIATION

Issued 1056 AM CST Fri Dec 19 2025

Expect easing northwest wind through the rest of this morning into the early afternoon. Winds will briefly become light an westerly during the late afternoon, and light and southerly this evening. South winds then increase overnight with gusts between 20 to 25 knots becoming prevalent toward daybreak on Saturday. Winds then become westerly and northwesterly Saturday afternoon following a cold front.

Remaining dry and overall VFR through tonight until a cold front approaches from the northwest. Ceilings should lower along the front becoming low VFR to MVFR (2500 to 4500ft). Some freezing drizzle and light snow is possible along the front between 12Z and 18Z Sat.

CMiller

MARINE

Issued 350 AM CST Fri Dec 19 2025

983 mb low pressure is centered near the Ontario-Quebec border early this morning, leading to gusty northwest winds across the open waters. Gusty conditions will continue into this morning and afternoon. Gale Warnings remain in effect until 12 PM CST over the southern two-thirds of Lake Michigan, and until 3 PM CST over the northern third. Areas of snow showers will continue on the back side of the low through this afternoon. Winds will subside from late afternoon through the first half of this evening as a narrow area of 1016 mb high pressure approaches and crosses the open waters. Areas of moderate freezing spray will continue into this afternoon, with conditions improving by this evening.

High pressure will quickly shift east of Lake Michigan tonight, bringing a southerly wind shift to the open waters. Southerly winds will quickly become gusty by daybreak Saturday as 996 mb low pressure moves into southwestern Ontario. Winds may briefly approach gale force over the southern third of Lake Michigan during the early morning hours Saturday, though any such gusts aren't expected to be widespread enough to justify headlines at this time. The low will progress toward the Ontario-Quebec border Saturday night, bringing a gusty northwest wind shift to the open waters. Widespread gale force gusts are anticipated during this time frame, particularly over the northern two-thirds of the waters. A Gale Watch has thus been issued between 3 PM CST Saturday and 3 AM Sunday for the northern two- thirds of Lake Michigan. Winds will taper Sunday morning as 1032 mb high pressure moves into the Upper Midwest. Periods of snow showers & light to moderate freezing spray will accompany the passing low Saturday & Saturday night.

Gusty northwest winds continue through the first half of this morning in nearshore zones, where a Gale Warning remains in effect until 9 AM CST. Winds will gradually decrease by this evening, though Small Craft Advisory conditions will continue through the first half of the afternoon hours. Areas of light to moderate freezing spray are possible. Winds will increase & shift southerly tonight as the next area of low pressure builds into the Northern Plains. Small Craft Advisory conditions are expected to return by midnight. The aforementioned area of low pressure will move into Quebec Saturday night, bringing a gusty northwest wind shift & continued Small Craft Advisory conditions. Additional light to moderate freezing spray is possible during this time frame. Winds will taper Sunday morning.

Quigley

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Gale Warning...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671- LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874- LMZ876-LMZ878 until noon Friday.

Gale Watch...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567- LMZ669-LMZ671-LMZ673-LMZ675-LMZ868-LMZ870-LMZ872-LMZ874- LMZ876...3 PM Saturday to 3 AM Sunday.

Gale Warning...LMZ261-LMZ362-LMZ364-LMZ563 until 2 PM Friday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 2 PM Friday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...11 PM Friday to 8 AM Sunday.