973 FXUS63 KMKX 190753 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 253 AM CDT Thu Jun 19 2025 .KEY MESSAGES... - Isolated to scattered storms possible (15-30%) this afternoon into the evening. - Overnight shower and storm chances will increase into Friday morning with remnant MCS moving through (50-70%). - Additional shower/storm chances Friday afternoon (15-30%). - Hot and humid conditions are expected for the weekend into early next week. Maximum heat indices of 100 to 105 degrees are forecast each day. && .SHORT TERM... Issued 255 AM CDT Wed Jun 18 2025 Today Through Friday night: Early this morning some lingering showers will push out with the low pressure system in eastern lower Michigan. Clearing skies expected during the morning hours with drier conditions. Into the afternoon today we will start to see a weak surface low develop in northeast WI with some shortwave activity sliding down the ridge behind the departing trough. While there may be some weak WAA the main question with this will be whether there will be enough moisture to get convection into southern WI. Most large scale models actually keep the mid to upper levels fairly dry. This would seem to at least prevent much in the way of precip developing over southern WI. However, CAMs definitely leave the door open for some development in northern WI tracking through parts of southern WI, primarily east central WI. Any convection pushing through southern WI looks likely to be isolated to scattered at best but with deep layer shear around 30-40 kts we cannot rule out a stronger storm with this. The best potential with this will be the mid afternoon through the mid evening. Into the late evening and overnight period things will get a little interesting as models seems to point toward a late evening developing MCS in central MN with this tracking southeast overnight. The primary driver for this appears to be the strengthening LLJ stretching into central MN. The LLJ will swing east across southern WI into Friday morning. There will be some shortwave activity as well but the LLJ is the primary feature. So storms are expected to track through southern WI late overnight into Friday morning. By the time things reach the CWA it may very well be largely just showers with some embedded weak storms as it encroaches on drying air and lower instability. Linger storm potential is more likely where better instability will be on the western fringes of the remnant MCS, likely west of the CWA. However given the forcing and shear from the LLJ (0-6km shear of 50+ kts) we certainly cant rule out storms being stronger when they push in but the lack of instability looks to be the main drawback with potential. This appears likely to clear out by late Friday morning with another period of clearing skies. It is worth noting that MCS formation can be a bit uncertain with models and how things evolve is still uncertain so it is certainly worth monitoring this as additional model runs come in. The most uncertain aspect at this time appears to be the timing of this remnant MCS. Friday afternoon and evening will feature additional rain and storms chances as strong low over the Central Plains stretches a warm front over parts of the western Great Lakes region. In addition we may see some shortwave energy riding down the ridge moving overhead. Overall, models largely agree that the best chance for activity will be further north perhaps nicking parts of east central WI again. However, given strong deep layer shear its worth monitoring as we could certainly see stronger storms should any develop over the area but at this juncture that potential seems limited in southern WI. Kuroski && .LONG TERM... Issued 255 AM CDT Wed Jun 18 2025 Saturday through Tuesday: The upper-level ridge axis will settle over WI this weekend contributing to heat concerns. Model trends continue and consistently show daytime temps in the 90s with very humid conditions as dewpoints climb into the upper 60s and even low 70s. The combination of hot temps and muggy conditions will likely result in heat indices climbing into the upper 90s and even toward/exceeding the triple digits each afternoon. The hottest temps/heat indices continue to favor southeastern WI as the stiff southwesterly wind paired with a bit of downslope off the Kettle Moraine will warm things up a bit more. Also it is not entirely out of the question to see temps approach triple digits in a few locations, but confidence remain very low at this point with ensembles potential less than 10%. Given the consistent in the temp and heat indices trends, will need to keep an eye on potential headlines highlighting the heat related impacts. Ridge axis slides a bit east for the start of next week and may not be quite a hot, but still looking at temps in the upper 80s to lower 90s for Monday before a cold front works its way into the region. Timing/progression and precip associated with the boundary will play a role on the temps for Monday and Tuesday. However run to run variability in the frontal progression remains in question and looks to continue to waffle around this far out on the models. Nevertheless will be some increase PoP chances with it and cooler temps compared to this weekend. Wagner && .AVIATION... Issued 255 AM CDT Wed Jun 18 2025 Continue to see lower ceilings and visibility in southeastern WI but this is projected to move out over the next few hours. Some showers in southwest WI up toward central WI will continue east this morning gradually dissipating with some potential impacts to VSBYs for brief periods. Looking dry into the daylight hours with clouds generally pushing out from west to east during the morning become clear by the afternoon. Into the afternoon we are looking at isolated shower/storm potential across east central WI into the evening. This potential will continue into the overnight period ahead of models now showing increased potential for a dying storm system overnight into Friday morning. This remains a bit uncertain but some storms would be possible though likely weak given timing. Impacts to VSBYs are the most likely especially further west where better potentially for heavier rains and weak storms exist. CIGS are a bit more uncertain but some MVFR CIGS would certainly be possible with this though they are not expected at this time. Kuroski && .MARINE... Issued 255 AM CDT Wed Jun 18 2025 Low pressure over lower Michigan will continue to track across the eastern Great Lakes region early this morning. Expect lighter northwest winds this morning as low pressure pushes further east then will back to southwesterly later this afternoon into Friday. Will continue to see stronger southerly winds through the weekend as a deepening low pressure develops over the Dakotas and slowly move into the Upper Midwest early next week. Gales are not expected with this system at this time. However, we should expect Small Craft Advisory conditions from Saturday through most of Sunday for breezy southwest winds with a chance on Monday as well. Kuroski && .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