Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
163 FXUS63 KMKX 300752 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 252 AM CDT Sat Aug 30 2025 .KEY MESSAGES... - Small chances (~10-20%) for a few light sprinkles or showers through 10 AM, particularly along/south of I-94 & US-18. - Chances (~20-30%) for areas of fog through sunrise and once again tonight, particularly along/west of the Kettle Moraine. - Dry conditions with a gradual warming trend rest of this weekend into early next week. - Next shower and thunderstorm chances (~40-60%) return to the forecast Wednesday into Thursday. && .SHORT TERM... Issued 255 AM CDT Sat Aug 30 2025 Today through Sunday: Synopsis/Mesoanalysis: High pressure is centered over Lake Michigan early this morning, resulting in generally light and variable surface winds across southern Wisconsin. Just above the surface, model analyses indicate an area of 925 mb baroclinicity stretching from near the Twin Cities southeast into north-central Illinois. Weakly convergent 925 mb winds have encouraged low stratus development within the area of baroclinicity, with nighttime microphysics imagery showing broken to completely overcast skies in most locations outside of the far northeast and southwest. A few isolated rain showers are evident in KMKX radar imagery, particularly in southeastern Wisconsin where lift is a touch greater in proximity to a departing shortwave. Isolated sprinkles and light rain showers will remain possible through ~10 AM primarily along and south of the I-94 and US-18 Corridors, with completely dry conditions becoming established by late morning. Dry conditions will continue through Sunday & the conclusion of the short term period, with Sunday`s high temps forecast to be a touch milder relative to today. Areas of fog are possible through dawn & once again tonight, particularly along and west of the Kettle Moraine. Rest Of Overnight: A few sprinkles or very light rain showers will linger, particularly across the southern half of the area. Minimal if any accumulation is anticipated in any sprinkles or showers. Areas of fog remain possible along and west of the Kettle Moraine, though coverage is likely to be hindered by the relatively widespread low stratus that has developed across southern Wisconsin. Will nevertheless be monitoring for isolated pockets of < 1 mile visibilities, particularly in Sheboygan and Lafayette/Green Counties where conditions have remained mostly clear through 2 AM. Slow down, use low beam headlights, and allow for extra following distance if encountering patches of fog through daybreak. Any fog development will quickly diminish following sunrise. Today Through Sunday: Any lingering sprinkles or light rain showers will dissipate by mid-morning. An upper disturbance over the Missouri Valley will be far enough way to keep conditions dry through this afternoon, though it will be close enough to support scattered to broken upper clouds. Skies will clear this evening, combining with light surface winds to lead to cool overnight lows. Given anticipated efficient radiational cooling, additional fog development is expected once again overnight along/west of the Kettle Moraine, with trends being monitored for possible locally dense fog. Fog will quickly burn off after sunrise, with mostly sunny skies leading to slightly milder high temperatures on Sunday afternoon. Quigley && .LONG TERM... Issued 255 AM CDT Sat Aug 30 2025 Sunday night through Friday: Quiet start to next week with large scale ridging building into the north central US with high pressure actually strengthening over the Great Lakes region. This looks very likely to keep us dry through Tuesday before the high pressure region starts to breakdown and the ridge aloft gets cut off and pushed out to the east with and upper low digging down through central Canada. By Wednesday (early as late Tuesday night), we will start to see that upper trough dig down into the western Great Lakes region with a developing surface low in Ontario pushing east. With plenty of upper level support and midlevel moisture this surface low will swing a front through the region. Still plenty of uncertainty on the actual timing of this but sometime Wednesday it is expected with rain likely and a slight chance for storms associated with it. This frontal passage will usher in much cooler temperatures with rapidly falling heights. While Thursday may end up fairly cool but quiet another upper low will swing in behind it for Friday and bring another frontal passage with showers and storms possible. A brief period of well below average temps and lows in the 40s would be expected. Into next weekend heights will rise back up as the upper low departs with potential for zonal flow and quieter weather. Kuroski && .AVIATION... Issued 255 AM CDT Sat Aug 30 2025 Low stratus clouds have developed across most of southern Wisconsin early this morning, with mostly VFR conditions prevailing as of 2:40 AM CDT. Bases have periodically dropped to and below FL030 at MSN, with forecast guidance suggesting additional potential for CIGs in the FL020-FL030 through daybreak across the west. Have thus maintained a forecast for prevailing MVFR in the 06Z update at MSN and JVL, and will continue to monitor trends through the remainder of the predawn hours. Should periods of MVFR CIGs become more sporadic, will consider lifting prevailing MVFR mentions in favor of TEMPO groups. Will also be watching for any eastward progress of MVFR CIGs, which would warrant potential MVFR TEMPO groups at UES. Any MVFR CIGs will improve after sunrise, resulting in a return of prevailing VFR flight categories at all southern Wisconsin terminals by mid-morning. Variable to light east-northeast winds will continue through tonight. FG development along and west of the Kettle Moraine can`t be entirely ruled out through daybreak, but is far more probable tonight into early Sunday morning. Will continue to monitor forecast guidance trends and insert prevailing BR/FG groups if necessary. Quigley && .MARINE... Issued 255 AM CDT Sat Aug 30 2025 1020 mb high pressure is centered over central Lake Michigan this morning, resulting in light east-northeast winds across the southern third of the open waters and light/variable winds further north. The high will linger over the Lower Peninsula of Michigan through the beginning of next week, resulting in broadly persistent light/variable winds through Monday afternoon. Similar to ongoing conditions, periods of more sustained east-northeast winds may develop over the southern third of the waters both tonight and Sunday night. Sustained south to southwest winds will become established Tuesday afternoon, and will steadily increase Tuesday night as 1010 mb low pressure migrates from Ontario toward Lake Superior. The low will progress toward the Ontario-Quebec border on Wednesday, dragging a cold front across the open waters in the process. The frontal passage will result in a northwest wind shift, with winds becoming gusty Wednesday afternoon and evening. While the current forecast continues to keep gusts just below gale thresholds, upward trends are possible as this portion of the period draws closer. Breezy northwest winds will continue through the day on Thursday behind the departed cold front. Periods of showers and thunderstorms will accompany the passing cold front Wednesday morning through Wednesday night. It remains too early to definitively indicate if gusty thunderstorm winds or waterspouts will be possible in any of this activity, though forecast trends will be closely monitored through the beginning of next week. Mostly light and variable winds continue in nearshore zones through Monday with high pressure lingering over Lower Michigan. South- southwest winds will establish during the day on Tuesday as low pressure moves into Lake Superior. A cold front will cross nearshore zones on Wednesday, resulting in a gusty northwest wind shift during the afternoon and evening hours. Small Craft Advisory conditions are possible, with forecast trends being monitored through early next week. Periods of showers and thunderstorms will accompany the passing front Wednesday morning through Wednesday night. Quigley && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ 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