Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
741 FXUS63 KMKX 062000 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 300 PM CDT Fri Jun 6 2025 .KEY MESSAGES... - Shower and storm chances return Saturday evening, with better chances for storms Sunday into Monday. Some storms may be strong Sunday and Monday. - Temperatures will remain within a few degrees of normal through early next week. && .SHORT TERM... Issued 300 PM CDT Fri Jun 6 2025 Tonight through Saturday night: Wiggles in the 500mb flow aloft will continue to spark light, widely scattered shower activity into this evening over parts of central WI, with activity waning as diurnal heating tapers into the night. South central to southeast Wisconsin will mostly likely continue to remain dry with clearer skies. With high pressure still over the region and dry air at the surface (Surface Tdds are around 10 degrees), most of this light shower activity over central WI will appear on radar, but likely fail to reach the ground or only produce a few sprinkles with virga aloft. Shower coverage will decrease overnight, but continuing wiggles in the flow aloft will keep some scattered showers going closer to the Mississippi River Valley into tomorrow morning. A more pronounced shortwave trough is then expected to move from west to east over the Corn Belt Saturday afternoon. Since yesterday, models have shifted this shortwave a bit further south toward the IA/MO border and IL, diminishing the coverage of showers over southern WI for Saturday afternoon. A few scattered pop-ups (~15% chances) can`t be ruled out over south-central/southeast WI during the late afternoon and evening, but the bulk of the rain activity looks to scoot by to the south of Wisconsin closer to the core of the better PVA from the shortwave. Any pop-ups in our area could have a rumble of thunder as CAMs depict CAPE around 500 J/kg with most of the CAPE at or above the freezing level. Subsidence behind the departing wave and diminishing diurnal heating will then end shower/storm chances Saturday evening. CMiller && .LONG TERM... Issued 219 PM CDT Fri Jun 6 2025 Sunday through Friday: Overnight Saturday into Sunday, low pressure will deepen and occlude over central Manitoba, shifting a cold front west to east across the Upper Great Lakes through the daytime hours on Sunday. Models vary concerning the timing of this front largely due to differing depictions concerning phasing with the shortwave that will move over the Corn Belt Saturday. For models that phase the cold front with the shortwave/sfc trough Sunday, the front will move through quicker/earlier in the day, blunting sufficient CAPE for strong storms during the afternoon. Models that don`t show this phasing have a much slower front, and therefore allow higher CAPE to be realized ahead of the front. With sufficient effective shear around 40 knots as the periphery of an upper level jet streak moves into the region, the mix of shear and CAPE would support storm organization and perhaps a few strong/marginally severe storms over south central to southeast WI Sunday afternoon. At this time, current thinking is that this solution is favored given more models exhibiting this behavior. We`ll continue to keep an eye on the storm threat as models hone in on Sunday with time. Beyond, a cut off low is expected to dip southeast out of Canada on Monday, bringing a reservoir of cold air aloft to the region. Daytime heating will steepen low level lapse rates, and scattered shower and storm activity is expected to blossom during the afternoon. At this time, a second sneak round of strong to marginally severe storms capable of hail and gusty winds look possible on Monday, given modest mid-level lapse rates around 6.5 to 7 C/km and somewhat dry low levels. Tuesday, the cutoff low may linger leading to more afternoon scattered rain/thunder, but dry air wrapping into the back of the broad cyclonic flow over the Upper Great Lakes may put a lid on overall shower/storm activity. High pressure then builds in mid-week. CMiller && .AVIATION... Issued 212 PM CDT Fri Jun 6 2025 Expect continuing VFR conditions amid light northeast winds through the overnight hours. A few sprinkles may occur over central WI until sunset this evening. Tomorrow, winds come around to easterly, then southeasterly by the afternoon, and will remain light. A stray pop-up shower can`t be ruled out along the Wisconsin/Illinois border late Saturday afternoon and into the evening, but chances are low at this time (~15%). CMiller && .MARINE... Issued 225 PM CDT Fri Jun 6 2025 High pressure will linger over the Upper Great Lakes through Saturday, causing persistent light north to northeasterly winds. Winds will come around to southeasterly on Sunday ahead of a cold front and as the high pressure moves east out of the Great Lakes Region. Thunderstorms are expected along the front Sunday afternoon and evening. Moderate southwest winds are then expected Monday behind the passage of the cold front. Winds then come around to westerly by Tuesday and ease in strength as high pressure approaches the Middle Mississippi Valley. CMiller && .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