textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Dense fog may continue to spread northeast across the rest of the area overnight into Sunday morning.

- Warm temperatures and rain on Sunday will transition to snow as temperatures drop rapidly below freezing Sunday night. Expect widespread accumulations between 1 to 3 inches through Monday morning. Areas north of a line from Dodgeville to Port Washington stand the best chance to see between 3 to 5 inches of snowfall and gusty winds, and a Winter Weather Advisory is in effect for those regions.

- Wind gusts up to 50 MPH will be possible Sunday night through Monday. Winds up to 55 MPH may briefly occur along the Lake Michigan shoreline. A Wind Advisory has been issued for all of southern Wisconsin.

- Polar air returns Sunday night and continues through the end of next week, with temperatures remaining at or below normal. - Confidence has increased in storm force gusts Sunday night through Monday night. A Storm Warning is in effect for this time frame.

UPDATE

Issued 950 PM CST Sat Dec 27 2025

Dense fog continues for areas southwest of Madison, where a Dense Fog Advisory is in effect until noon CST Sunday. There is potential for the dense fog to spread across the rest of the area overnight into Sunday morning, as steady warm air advection in the low levels continues to feed moisture into the area.

Will monitor web cameras and airport observations and expand the advisory northeastward if necessary. The dense fog should dissipate once rain starts to develop and move northeast into the area by later Sunday morning into the early afternoon.

Otherwise, the headlines look reasonable for now with the Winter Weather Advisory in the north half with Dane and Iowa Counties Sunday night into Monday morning, and the Wind Advisory for the entire area Sunday night into Monday. Will have to monitor the Marquette/Green Lake County and nearby areas and see if higher snowfall amounts may occur there. There may be some rumbles of thunder that sneak into far southeast Wisconsin as well Sunday before the front moves through.

Wood

SHORT TERM

Issued 349 PM CST Sat Dec 27 2025

Tonight through Monday Night:

Subtle warm moist advection is anticipated overnight as sfc low pressure moves out of the Central Plains towards southern WI and a week warm front approaches the WI/IL border. With the WAA, fog is expected to spread in coverage overnight and light drizzle is anticipated to blossom over southern WI this evening and continue through the overnight hours. Some of the fog may become dense on a scattered basis.

There'll be a bit of a lull in the drizzle after dawn tomorrow as the forcing for ascent from the WAA moves east into Lower Michigan. Fog will linger until rain moves in during the mid morning and continues through the afternoon as PVA from an approaching deep 500mb trough over the western Corn Belt overspreads the frontal boundary and the center of the sfc low moves directly over southern WI.

Late Sunday afternoon into Sunday evening, the low will rapidly deepen as it passes over southern Lake Michigan into the Mitten of Michigan State. As this happens, very strong winds are expected to spread into southern Wisconsin driven by a tight pressure gradient, causing very strong cold advection. A quick transition from rain to snow is expected from west to east between 6 and 9pm, with snow continuing overnight as the deformation band from the intensifying sfc low pivots and sinks southeast into Monday morning. While soundings show a fairly deep dendritic growth zone from 900 to 650mb at times, the strong winds to 50 mph will likely breakdown the dendrites to needles during the snow event, driving down snow ratios.

Snow is expected to then end Monday morning as the surface low pulls northeast, with cold breezy conditions expected for the rest of Monday.

A Winter Weather Advisory has been issued generally along and north of a line from Dodgeville to Port Washington from 6PM Sunday to Noon Monday. Along and north of this line, snow totals will range from 3 to 5 inches, while totals will be less south of this line. Blowing snow will generally be a concern everywhere however, given the high wind gusts to 50 mph. Impacts will be heightened in the advisory area given higher snow totals.

A Wind Advisory has also been issued from 6PM Sunday to 6PM Monday. Wind gusts up to 50 mph will be possible everywhere in southern WI during that time period. Some gusts to 55 mph may occur early Monday morning along the Lake Michigan shoreline.

CMiller

LONG TERM

Issued 250 PM CST Sat Dec 27 2025

Tuesday through Saturday:

An area of warm advection aloft is expected Tuesday into Tuesday night as a weak shortwave pushes through. This will bring light snow chances to at least the northeast forecast area, with models varying on how far southwest the light snow will reach. Temperatures will be a few degrees below normal Tue, with mostly cloudy skies anticipated.

A cold front will move through by late Tue night, keeping highs a bit under normal on Wednesday. Another shortwave will move through later Wed into Wed night, brining more light snow chances to the area. This system currently looks a little more likely to bring some light snow accumulations to the area than the Tue wave, with up to an inch possible per 12Z guidance.

A colder airmass will continue to push into southern Wisconsin Wednesday night into Thursday behind the departing shortwave. Wind chills may dip to the 0 to -10 range later Wed night (New Year's Eve) into early Thursday, with highs New Year's Day likely only reaching the teens. High pressure is expected to bring dry weather Thursday and Friday, with below normal temps continuing on Friday. Temps should warm back towards normal Saturday, with precip chances returning the the area by later Sat or Sat night.

DDV

AVIATION

Issued 950 PM CST Sat Dec 27 2025

Dense fog with visibility of one quarter mile or less continues for areas southwest of Madison, and there is potential for the dense fog to spread across the rest of the area overnight into Sunday morning.

For now, have one half to one quarter mile visibility for terminals overnight into Sunday morning, with continued low ceilings of 200 to 400 feet AGL. The gusty southeast winds near the lake may be limiting the dense fog for terminals nearby, but these winds should weaken overnight and may allow for the fog to become more dense. Generally light and variable winds should occur Sunday morning and early afternoon.

The dense fog should dissipate once rain starts to develop and move northeast into the area by later Sunday morning into the early afternoon. It may move into Kenosha and Milwaukee sooner, so visibility values may improve there first. Visibility of one half to one mile or so should then prevail through Sunday, becoming 1 to 2 miles Sunday night.

The ceilings should remain around 500 feet AGL or less into most of the rest of Sunday, before rising above 1000 feet AGL behind the cold front Sunday night. There may be some rumbles of thunder that sneak into far southeast Wisconsin as well Sunday before the front moves through.

The rain will quickly change to snow later Sunday afternoon into early Sunday evening west to east as the cold front moves through. The snow should be more of a powdery and fluffy character. Snowfall rates of one quarter to one half inch per hour should occur north of Madison and Milwaukee, including toward Sheboygan. Lower rates and amounts are expected toward Janesville and Kenosha.

Strong west to northwest winds are expected behind the front later Sunday afternoon into Sunday night, which will bring some blowing and drifting snow. Gusts of 40 to 45 knots are possible later Sunday night into early Monday morning.

Wood

MARINE

Issued 950 PM CST Sat Dec 27 2025

Moderate southeasterly winds will continue overnight, as low pressure around 29.6 inches approaches from the Central Plains. Winds are anticipated to ease Sunday morning, as the low moves closer to the lake and passes over the southern end of the lake through the afternoon.

A Small Craft Advisory is in effect for the nearshore waters into Sunday morning, for gusty southeast winds and building waves into the overnight hours, and lingering elevated waves into Sunday morning.

Sunday night, following the passage of the low, very strong northwest winds are expected, as the surface low deepens to around 28.9 inches as it moves northeast toward Lake Huron. Storm force gusts between 50 to 55 knots are expected Sunday night into Monday night, with the peak in gusts occuring between 3 AM CST to 6 PM CST Monday.

A Storm Warning is in effect for all of the open waters of Lake Michigan from 7 PM CST Sunday evening to 6 AM CST Tuesday. High waves are also anticipated, highest toward the eastern half of the lake.

While gales should ease after 6 AM CST Tuesday, breezy northwest to west winds are anticipated to continue through the week, as northwest flow and cold air take hold.

A Gale Warning is in effect for the nearshore waters Sunday evening into Monday evening, for frequent northwest gales to 45 knots.

CMiller/Wood

MKX WATCHES/WARNINGS/ADVISORIES

WI...Dense Fog Advisory...WIZ062-WIZ067-WIZ068 until noon Sunday.

Wind Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057- WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066- WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...6 PM Sunday to 6 PM Monday.

Winter Weather Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056- WIZ057-WIZ058-WIZ059-WIZ060-WIZ062-WIZ063...6 PM Sunday to noon Monday.

LM...Storm Warning...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 PM Sunday to 6 AM Tuesday.

Gale Warning...LMZ643-LMZ644...9 PM Sunday to midnight Tuesday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 9 AM Sunday.

Gale Warning...LMZ645-LMZ646...6 PM Sunday to midnight Tuesday.