


Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
623 FXUS63 KMKX 080246 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 946 PM CDT Mon Jul 7 2025 .KEY MESSAGES... - Shower and thunderstorm chances (~30-55%) return Tuesday, though an all-day washout is not expected. - Additional shower and thunderstorms forecast Friday through Saturday ahead of the next disturbance. && .UPDATE... Issued 935 PM CDT Mon Jul 7 2025 Looking fairly quiet for the remainder of the evening. There are a few isolated showers trying to develop across far southwestern WI, but they are struggling given the lack of forcing. Otherwise keeping an eye on the upstream line of showers and thunderstorms currently tracking across southern MN. Latest 00z HRRR, ARW, and NSSL-WRF prog a downward trend in the line and has it diminishing before reaching southern WI before seeing additional convective development later Tuesday morning into the afternoon. However, cannot rule out seeing some redevelopment a bit earlier into the early morning hours as suggested by the 00z NAM Nest, especially looking at the latest radar trends upstream showing a bit of an MCV type feature tracking across southeast MN. Overall, increased capping and lack of forcing mechanisms should limit this activity as it moves eastward into southern WI, but will need to monitor trends with that feature in southeast MN. Otherwise, previous forecast remain on track with additional shower and thunderstorm chances Tuesday afternoon/evening as the surface low and associated cold front pushing into the the region. Wagner && .SHORT TERM... Issued 309 PM CDT Mon Jul 7 2025 Tonight through Tuesday night: Partly cloudy to mostly clear skies across much of south central and eastern Wisconsin. Daytime heating has brought temperatures up into the mid 70s to low 80s and drier air is slowly working in from the north. Across far southwestern Wisconsin, isolated rain showers have developed. These showers are in a good area of CAPE with some diurnal lift. This narrow area will slowly move southeast with time and will nick part of western Lafayette and Iowa counties. Dewpoints are in the upper 60s across far southwestern Wisconsin which is good enough to support these showers. As we loose sunlight and drier air begins to push further westward the window for isolated rain showers will end. If storms get tall enough there could be a few rumbles of thunder, but there is very little shear in Wisconsin and overall rain motion is very slow around 10 to 15 kts. Rain should pulse up and fall back down and outflow boundaries that fan outward could produce some more rain showers so will have to keep an eye on that and increase POPS accordingly. There is no risk for stronger or severe weather with these showers. Conditions will briefly dry out again late this evening into early tonight for southwestern Wisconsin. An upper trough and weak sfc front will advect eastward into Wisconsin Tuesday bringing our next chance for rain and thunderstorms. Precipitation is expected to begin early Tuesday morning in the predawn hours with a scattered line moving east across the area. CAMs again are all over the place with timing and exactly how this scattered line will move through so kept POPs more broad and a bit lower around 35 to 60%. This line should work eastward through the Tuesday morning commute exiting to the east by mid morning. This however will not be the end to our rain chances for the day. This initial line will set the stage for isolated to scattered storm development through the afternoon and into the evening. You can already see this line move southeast to the NW in Minnesota and the Dakotas. If this line does become more of an MCV as it rolls through instead of a broken line then more widespread rain and more develop from outflows are expected through the afternoon. Upper level lift will be over the Great Lakes Region for much of the day with some better shear so a more scattered or weaker line, could lead to unsettled clouds and isolated pockets of rain/storms throughout the day as mixing and sfc lift increases. Tuesday wont be a complete wash out of constant rain, but more of a few rounds of scattered to isolated development. While there will be some more shear in comparison to today, there isnt any organized convection anticipated. So not anticipating stronger or severe storms from any activity Tuesday. A few storms could produce some brief heavy rainfall and lightning. Tuesday night into Wednesday morning the pesky showers chances remain around 20-30% or less. The low pressure system will again be slow to exit the Great Lakes region, leaving broad lift across southern Wisconsin. In this type of environment, CAMs again are all over the place, but the next potential for rain heading into wednesday morning will likely be across south central to southeastern Wisconsin and these chances will decrease from the northwest to the southeast overtime. Patterson && .LONG TERM... Issued 309 PM CDT Mon Jul 7 2025 Wednesday through Monday: An upper level ridge will move into the Great Lakes Region Wednesday and begin exiting to the east early Thursday. Despite the large scale subsidence, there will be some mid level and low level transient lift to keep in some low chance POPs for both days (10-15% or less). Majority of the area will remain dry and quite, but for the few expectations here`s the break down. For Wednesday, the frontal boundary from Tuesday will again be slow to exit to the southeast. So rain will linger through the morning hours. Heading into the afternoon the sfc low will be just to our south in the Ohio River Valley which will leave some broad weak lift across our forecast area. Only a few models are picking up on this (the NAM being one of them) and dewpoints should remain in the 60s. So there could be enough lift to squeeze out some isolated showers, but more likely is partly cloudy to overcast skies. Timing and exact locations for this 10% chance of rain vary wildly. Now for Thursdays very small chance, there will be a stationary front that will wiggle around central Illinois. There will be sfc high pressure to our north, but these very low chances (10% or less) hinge on the few runs of guidance that have this boundary drifting more northward overtime. Should this occur, southern Wisconsin would again have weak board lift and dewpoints in the 60s. So just enough moisture and lift to get isolated showers. Now, the bright side is chances are low and the vast majority of southern Wisconsin will remain dry both days. Highs will be pleasant and warm in the upper 70s to mid 80s both days. Friday into Saturday the ridging breaks down and moves eastward as a stronger trough and sfc low pressure system advect toward the state. Friday afternoon into Friday night will be the best chance for rain through the extended with POPs of . There should be decent upper level support as Wisconsin will be on the leading edge of this stronger upper level low. There will be some interesting phasing as a shortwave tries to move out ahead of the main trough. So no shortage of upper level support, but phasing issues could weaken the overall effectiveness for stronger storms and broaden the window for rainfall. There is a lot of uncertainty on the track of the sfc low with some models trying to bring it through southern Wisconsin and other opting for a more northward track. The farther north the track goes the more likely our forecast area is to end up in the warm sector and get good instability for storms. Another thing to keep an eye on for this system is moisture will be increasing and so to will PWATs. Heavy rain will be possible with high PWATs, but this system is expected to be more transient and move through quicker. While no day will be a washout of rain, its a good week to keep an eye on the forecast. Through the rest of the weekend and into next week there is still a lot of uncertainty so low chance POPs sneak in yet again. As the upper level trough and sfc low exit Saturday, models are split on the timing and strength of another trough/low right on the heels of the first. The GFS seems to be the most amplified and fastest, but too much uncertainty to draw meaningful conclusions on rain/storms. Temperatures will remain consistent through the extended with highs in the mid 70s to mid 80s. && .AVIATION... Issued 945 PM CDT Mon Jul 7 2025 Light and variable winds will prevail along with VFR conditions tonight as high pressure works its way across the Upper Great Lakes. Keeping an eye on the line of showers and thunderstorms currently tracking across MN late this evening. Overall models trends favor the line weakening before reaching southern WI. However, cannot rule out it staying organized enough and/or redeveloping as it tracks across the Mississippi River Valley through the early morning hours. Otherwise, looking at southerly winds picking up through the morning with additional shower and thunderstorm chances Tuesday afternoon and evening as low pressure and its associated weak cold front tracks across the area. With any shower or thunderstorm activity, expect lower ceilings and visibility to accompany this activity. Wagner && .MARINE... Issued 309 PM CDT Mon Jul 7 2025 High pressure in the Hudson Bay remains as low pressure continues to exit the region to the east. Winds have come down today as the pressure gradient has weakened. A second weak area of surface high pressure will move through tonight and cross Lake Michigan bringing light and variable winds. This are of high pressure will quickly move east and winds behind the high will become south to southeasterly. On the heels of this exciting sfc high a broad low will move into the Upper Mississippi River Valley. The low will pull a weak surface front across Lake Michigan Tuesday night, resulting in a northerly wind shift. Areas of showers and thunderstorms will accompany the approaching boundary, with severe weather not expected at this time. North to northeast winds will remain entrenched through Thursday. Winds will turn out of the southeast on Friday as a second area of 29.8 inch low pressure moves into the Great Plains. The low`s approach will bring additional chances for showers and thunderstorms to the open waters Friday into Saturday. Patterson && .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