NWS Milwaukee Forecast Discussion
103 FXUS63 KMKX 190823 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 323 AM CDT Sat Apr 19 2025 .KEY MESSAGES... - Light winds and dry today and tonight. - Increased rain chances (70-90%) for Sunday afternoon into Monday morning with the heaviest rainfall along and northwest of the lower Wisconsin River Valley. - Warm up Tuesday onward with well above normal highs for the middle of the week. && .SHORT TERM... Issued 319 AM CDT Sat Apr 19 2025 Today and Tonight: Lingering low-level clouds will linger across southern WI through the early morning hours behind the cold front. This will also result in pockets of drizzle/mist mainly across eastern half of the CWA. Otherwise, seeing the cooler airmass settle into southern WI this morning as temps drop into the 40s with the northwesterly flow. Will see temps gradually rise through the day as skies are progged to clear with the incoming subsidence from surface high pressure and building upper-level ridge around the region. Looking at highs to top off in the 50s across much of the area. Given the lighter winds and increased temp gradient between inland and Lake Michigan, would not be surprised to see a lake breeze develop and push inland later this afternoon. This would bring a "cooler by the lake" setup and depending on how quickly it sets up make ultimately impact the highs for the lakeshore areas. Nevertheless, will still see near to slightly below normal temps today. Light winds, clear skies as the surface high tracks across WI overnight will lead to cooler, but near normal overnight lows in the mid to upper 30s. Cannot rule out dipping colder in some spots given this setup toward the freezing mark. And although we are not quite in the growing season per say, this setup would lend way to the potential for some frosty conditions overnight into early Sunday morning. Wagner && .LONG TERM... Issued 319 AM CDT Sat Apr 19 2025 Sunday through Friday: Low pressure developing over the central Plains early Sunday morning will track northeastward throughout the day as high pressure over the Great Lakes region retreats. Pressure gradient between these two systems will create an easterly wind field Sunday, which will allow cool / stable air to advect in from Lake Michigan, holding Lake MI shoreline high temperatures to the upper 40s. It is tough to determine how long the blocking influence of the high will hold, but mostly dry weather is expected for Sunday morning, followed by increasing chances for rain (from south to north) as the low pressure draws closer, peaking Sunday evening / Sunday night. Looking at a potential for additional soaking rainfall amounts as the low pressure tracks across the area. This evening`s NBM run favors the highest QPF swath along and just northwest of the lower half of the Wisconsin River Valley with high (>80%) chance for half an inch or more and even >60% chance of seeing 1 inch or more for a 24hr period between Sunday and Monday. Similar trends are seen with the 00z ECMWF ensembles as well as CMC ensembles, while the GFS ensembles favors the heavier swath more northwestward. Nevertheless, additional rainfall is looking increasingly more likely across our northwestern portion of the CWA while areas to the southeast still may see rainfall, but generally looking at lower overall QPF totals of less than a half an inch through Monday. Models have a decent consensus on the low pressure track, taking it northeastward through southern Wisconsin Sunday night / Monday morning. Both the timing of the approach and the easterly wind field off Lake Michigan are likely to inhibit severe storm potential, though we would not be surprised to hear a few rumbles of thunder at night or on Monday. Rain lingers into Monday morning, decreasing chances into the afternoon. CAA behind the departing low will be very short lived, allowing another low pressure over the Dakotas Tuesday morning to resume southerly WAA, leading to noticeably warmer temperatures and a chance for Tuesday PM / Tuesday night showers and thunderstorms. Occasional chances for showers and thunderstorms remain in the forecast through the end of next week. Sheppard/Wagner && .AVIATION... Issued 319 AM CDT Sat Apr 19 2025 MVFR/IFR ceilings with a few pockets of LIFR in southeastern WI will linger through the remainder of the early morning. Also seeing lower visibility accompanying the lower ceilings associated with drizzle/misty conditions, mainly for areas closer to Lake Michigan. Expecting to see these conditions gradually improve through the morning as high pressure begins to build into the the Upper Midwest. Looking at lighter winds and VFR conditions for the afternoon through the evening. However given the light winds today, cannot rule out seeing a lake breeze develop this afternoon and push inland. This will likely result in a brief period of gusty winds accompanied by an easterly wind shift for terminals closer to the lakefront (MKE, ENW, and SBM). Wagner && .MARINE... Issued 319 AM CDT Sat Apr 19 2025 Drier conditions and lighter northerly winds are expected today as high pressure begins to build in from the west. Will see more variable winds overnight tonight as the high pressure builds as it pushes over Lake Michigan. Then the high pressure quickly shifts eastward as low pressure lifts into the area from the southern Plains. Expect increasing east to northeasterly winds to develop by Sunday as Lake Michigan sits in between the departing high and an approaching low. As the low pressure lifts northeastward across the northern half of Lake Michigan, it will deepen on Monday with southerly winds ahead of it during the day then becoming northwest behind it Monday night. Higher waves are expected on to accompany the breezier southerly winds, particularly across the central half of the lake. Sunday into Monday looks to be window for small craft conditions during this timeframe. Wagner && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/NWSMilwaukee www.twitter.com/NWSMilwaukee www.youtube.com/NWSMilwaukee