Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
083 FXUS63 KMKX 121603 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1103 AM CDT Sun Oct 12 2025 .KEY MESSAGES... - Low clouds will linger along the lakeshore into this afternoon given southeasterly fetch off of the lake. - Chance (20-30%) of light showers overnight into Monday. && .UPDATE... Issued 1100 AM CDT Sun Oct 12 2025 Clouds will tend to linger into the afternoon along the lakeshore, as southeasterly fetch off of the lake will continue to advect moisture inland. Otherwise, forecast details remain on track. CMiller && .SHORT TERM... Issued 350 AM CDT Sun Oct 12 2025 Today through Monday: Low clouds are the main story for today. Widespread low clouds are present over southeast Wisconsin and portions of south central WI. The western edge is just west of Madison at this time. The clouds were originally formed due to the cool air over the relatively warm lake (lake effect). As winds shifted to the southeast overnight, they pushed the low clouds inland. In addition, warm air advection began just above the surface helped to trap the moisture and low clouds beneath a dry layer in the mid levels. We can expect increased mixing in the low levels during the day, so the low clouds should become more scattered and probably diminish this afternoon as drier air takes hold. There is a chance of light rain tonight. A low pressure trough (oriented north to south) approaching from the Northern Plains will reach the western Wisconsin border around midnight and slowly cross the state overnight through Monday afternoon. The reason for the slow movement is that the parent low is way up in Manitoba and will be occluding during this time. As a result, the trailing cold front will be weakening as it crosses southern WI. The period when the synoptic forcing and moisture line up at all levels will be brief for us, and it looks like it will be between 2 AM and Noon Monday. The NAM is the most optimistic for deep moisture, while most of the other models have some dry air in the low levels to overcome or too much upper level dry air. The meso model forecast reflectivity show a n-s band of light rain tracking across southern WI from 1 AM to 8 AM. While the precip will be light, I increased the chance for rain across all of southern WI to the 20-30% range. The frontal boundary and therefore the light rain chances may linger over southern WI through Monday afternoon. Depending on when the clouds clear, temperatures could reach the lower 70s for inland areas. But if the clouds hang on through the afternoon, then highs will only be in the upper 60s. Cronce && .LONG TERM... Issued 350 AM CDT Sun Oct 12 2025 Monday night through Saturday: 500 mb cluster analysis shows a ridge axis lingering over the region for most of next week, with continued positive anomalies. High pressure at the surface should slide southeast into the region Tuesday into Wednesday. There may be passing vorticity maxima at 500 mb during this period that may bring some clouds and showers, though the air column is fairly dry below the middle levels on forecast soundings. Ensembles are not showing much in the way of measurable precipitation either during this period, so PoPs may need to be lowered in later forecasts. Temperatures look to be near or a little above seasonal normal values. Warm air advection later in the week may bring enough moisture into the area to bring some chances (20 to 40 percent) for showers and perhaps a few storms at times. Temperatures should trend upward by Friday, with above normal temperatures lingering into next weekend, supported by ensemble trends. Wood && .AVIATION... Issued 1100 AM CDT Sun Oct 12 2025 MVFR clouds will continue to linger along the lakeshore given onshore moisture advection and relatively warm lake waters. Farther inland over south central to southwest Wisconsin, VFR pervails. Similar conditions are expected into tonight before rain approaches during the early morning hours. Winds will remain breezy and southeasterly. CMiller && .MARINE... Issued 350 AM CDT Sun Oct 12 2025 High pressure over eastern Canada will remain in place today, while a low pressure trough crosses North Dakota. Between these systems, breezy southerly winds are expected over Lake Michigan today through Monday afternoon. Winds will shift to the west Monday afternoon behind the associated cold front. High pressure will then move across the Upper Great Lakes region Tuesday through Wednesday. A Small Craft Advisory remains in effect for waves 4 to 6 feet due to persistent onshore winds from mid morning through Monday afternoon. A few wind gusts up to 25 kt will be possible today. The southern Nearshore zone from Winthrop Harbor to Wind Point remains without an Advisory, but we may need to add it for a shorter period from late tonight into Monday due to the orientation of the shoreline near Wind Point. Cronce && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Small Craft Advisory...LMZ643-LMZ644 until 1 PM 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