####018008135#### FXUS63 KMKX 062117 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 317 PM CST Sat Dec 6 2025 .KEY MESSAGES... - Widespread accumulating snowfall this evening into early Sunday. Snow totals of 1 to 3 inches north of I-90/I-94 and 3 to 5 inches along and south. Localized totals around 6 inches are possible in far southwestern and far southeastern Wisconsin. A Winter Weather Advisory is in effect for Sauk County to Milwaukee County and southward. - Additional rounds of snowfall will be possible again Monday night into Tuesday and Tuesday night into Wednesday. Tuesday temperatures will likely rise above freezing, which means snow may start as rain. - Additional rounds of snowfall are then possible through the end of the work week, but confidence in timing is much lower. - Below normal temperatures continue through next weekend. && .SHORT TERM... Issued 317 PM CST Sat Dec 6 2025 Tonight through Sunday night: The clipper system tracking into southern Wisconsin tonight has taken shape across western Iowa and southwestern Minnesota this afternoon, with the strongest precipitation/frontogenesis area developing over central to northern Iowa. This lends credence to the southward shift of the mesoscale modeling that indicates the majority of QPF will fall across the southern two tiers of Wisconsin counties, but some individual models still indicate potential for a band of heavier precipitation in the Wisconsin River Valley, so for now will let Sauk County remain in the Winter Weather Advisory (currently covering Sauk County to Milwaukee County and all areas southward). Deep dendritic growth zones are noted in the soundings from the Wisconsin River Valley, so even with a shorter period of precipitation rates may reach near 1"/hr and create hazardous travel conditions. These 1"/hr rates are also possible in banded precipitation near the WI/IL border, where precipitation also lasts longer, and in far southeastern Wisconsin where some lake enhancement is possible as winds turn northeasterly. Therefore, local accumulations up to 6 inches are possible along the border regions. Elsewhere within the Winter Weather Advisory, expect accumulations of 2 to 5 inches. Precipitation will taper off into Sunday morning, with skies expected to clear through the day as arctic high pressure pushes in with northerly winds. Expect highs in the upper teens. Winds shift to northeasterly overnight Sunday, potentially bringing a diffuse band of lake effect snow slightly onshore. Not anticipating any strong banding or significant accumulations at this time (~20 percent chance of precipitation). Lows around zero degrees are expected across inland regions, with areas east of the Kettle Moraine slightly higher in the 5 to 15 degree range. MH && .LONG TERM... Issued 317 PM CST Sat Dec 6 2025 Monday through Saturday: A lake effect snow band may brush southeast WI Monday morning before getting pushed into the north half of the lake by increasing southerly winds during the afternoon. High temperatures will reach the lower 20s and we can expect mostly cloudy skies. A shortwave trough will track across WI during the day Monday, but the weak lift from vorticity and warm air advection (and dry low levels) should keep precip confined to central and northern WI during the afternoon. A more robust shortwave trough will progress through central and northern WI Monday night into Tuesday morning. Broad low and mid level lift ahead of and along this wave will bring widespread, light snow to WI. Despite the likelihood of seeing snow (50-65% north of I-94 and 30-50% south), it only looks like around a half inch near Fond du Lac and Sheboygan, and trace amounts near the IL border. Snow should exit by mid Tuesday morning. The next surface low in response to a stronger mid level shortwave trough will track from Saskatchewan to west central MN on Tuesday and across central WI Tuesday night. The 12Z runs of the ECMWF and GFS have come into better agreement on the track of the low, but there is still some uncertainty. The big challenge with this Tuesday night event will be the precip type for southern WI. We will begin above freezing Tuesday afternoon in the warm sector and then likely remain in that warm sector if the low tracks across central WI. With loss of daylight, temps will probably sink just below freezing, but the temps aloft (925-850mb) should be in the 0-2C range south of the low. As long as we have deep enough saturation into the snow growth zone, then snow will be the primary ptype. But if we lose ice crystals, a wintry mix could occur. These are the details that will need to get hashed out as we get closer to the event. Another arctic blast will move in behind that low. Gusty northwest winds are expected Wednesday afternoon, and lows will drop into the single digits for most areas Wednesday night. We could also see scattered light snow showers. A swath of snow is expected to fall across the Midwest on Thursday. There are still big differences in the forecast location due to uncertainty in the amplification of the mid level shortwave trough. Some models clip far southern WI with the snow and others miss us all together. And... there is yet another chance for snow next weekend. Cronce && .AVIATION... Issued 317 PM CST Sat Dec 6 2025 A deck of MVFR clouds is maintaining its hold on far southern Wisconsin, while a main deck around 3200 ft is slowly overtaking the rest of southern Wisconsin this afternoon ahead of the snow system tonight. Initial rounds of flurries and light snow are expected to maintain VFR conditions, but expecting ceilings to rapidly fall to 1000-1900 ft as heavier snow moves in late this evening into tonight. The heaviest snow is expected along the WI/IL border, bringing visibilities down to 1/2 mile in some places and ceilings down to IFR. Snow will taper off from west to east early Sunday morning and VFR conditions will prevail afterwards, although MVFR ceilings will likely linger along Lake Michigan terminals through late morning/early afternoon. Expect light and variable winds this afternoon to shift to northeasterly overnight and to northerly into Sunday. Gusts of 15 to 20 kt are expected throughout Sunday, with winds diminishing Sunday night. MH && .MARINE... Issued 317 PM CST Sat Dec 6 2025 Winds will become northerly tonight into Sunday and increase as low pressure crosses central Illinois and Indiana and high pressure builds into the Upper Midwest. A Small Craft Advisory is in effect for gusts up to 25 kt and high waves of 4 to 6 feet. Winds will shift to the south Monday afternoon as low pressure passes north of Lake Superior. Another stronger low will track from Minnesota to Sault Ste. Marie Monday night through Tuesday morning. A period of southerly gales up to 35 kt is looking more likely during this time, with gusts up to 40 kt possible over far northern Lake Michigan. The next low will track across central Wisconsin Tuesday night and then reach southern Ontario midday Wednesday. Gales are possible for the south half. MRC && .MKX WATCHES/WARNINGS/ADVISORIES... WI...Winter Weather Advisory...WIZ056-WIZ062-WIZ063-WIZ067-WIZ068- WIZ069...8 PM Saturday to 6 AM Sunday. Winter Weather Advisory...WIZ064-WIZ065-WIZ066-WIZ070-WIZ071- WIZ072...10 PM Saturday to 8 AM Sunday. LM...Small Craft Advisory...LMZ644...8 AM Sunday to 9 PM Sunday. Small Craft Advisory...LMZ645-LMZ646...8 AM Sunday to 3 AM Monday. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, X, and YouTube at: www.facebook.com/NWSMilwaukee www.x.com/NWSMilwaukee www.youtube.com/NWSMilwaukee