Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
979 FXUS63 KMKX 150830 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 330 AM CDT Tue Jul 15 2025 .KEY MESSAGES... - Very warm and humid conditions today into Wednesday with maximum heat indices topping off in the lower 90s. - Increased shower and thunderstorm chances through the day Wednesday (50-80%) with lower chances (20-40%) lingering into Thursday. - Increasing potential (SPC risk 2 out of 5) to see stronger to even severe thunderstorms Wednesday afternoon/evening along with heavy rainfall across southern WI, but will depend on timing and placement of the cold frontal passage. - Looking cooler and drier later Thursday into Friday with high temps in the 70s and lows in the 50s to around 60F. - Unsettled weather returns for the weekend with 20-40% shower and storm chances each day. && .SHORT TERM... Issued 325 AM CDT Tue Jul 15 2025 Today and Tonight: Today is looking very warm and more humid as south to southwesterly flow advects in higher moisture. Dewpoints look to creep into the upper 60s to low 70s this afternoon while temps warm into the mid to upper 80s across southern WI. Will also see feel like temps in the low to mid 90s this afternoon as well. While expecting a predominantly dry forecast, some of the 00z CAMs such as the HRRR have hinted a few isolated pop-up showers to develop later this evening in far southeastern WI along a lake breeze as it may tap into the higher surface moisture. However given lack of upper-level forcing and dry model soundings throughout the column, will maintain no PoP mentions at this time, but cannot be completely ruled out. Otherwise, focus shifts to the trough progged to dig across the Northern Plains overnight with a mid-level shortwave trough ejecting out ahead of it. However, influence from this feature looks to remain upstream across MN/northwest WI overnight before moving in through the day Wednesday. Wagner && .LONG TERM... Issued 325 AM CDT Tue Jul 15 2025 Wednesday: A shortwave trough is expected to track into southwest WI Wednesday afternoon. This shortwave should be in the form of an MCV, remnant from anticipated convection over the Central Plains this afternoon through tonight. A primed environment will be in place over northern IL and southern WI Wed afternoon, with dewpoints in the lower to mid 70s, temperatures in the upper 80s, and CAPE around 1000 j/kg with no cap. The shear will be modest, around 20-25 kt, which would limit the sustainability and organization of storms. The expectation is that scattered thunderstorms will erupt over northern IL and southern WI as the shortwave/remnant MCV tracks into the region during peak daytime heating Wed afternoon. In addition, the main cold front will be tracking across northern/central WI and east-central MN during this time and could support scattered storms along it. There is a threat for damaging winds and 1 inch diameter hail with individual storms or clusters of storms. The tornado risk is low. However, better low level shear and would be along the lake breeze, so the timing and intensity of the storms moving into southeast WI will be important. If they arrive too late in the day, then the instability will be lower and therefore the storms will be weaker. There is still a lot of uncertainty in how these potential storms will play out, so keep up with the forecast. Late Wednesday night through Monday: The main upper trough will slowly slide across Lake Superior and northern WI Wed night, and the associated cold front will gradually make its way down through central and southern WI Thursday morning. There is a small chance for showers and a few rumbles of thunder along the front late Wed night through late Thu morning. High pressure will drift across WI Thursday afternoon through Friday. Highs will only be in the 70s Thu and Fri, and in the mid to upper 50s for most inland areas Thu night. Return flow around the high will start to increase the dewpoints again Friday night into Saturday. A storm complex may roll into southern WI on Sat. There is synoptic support from the right entrance region of a weak upper jet and also the nose of a low level jet, but this also looks like it could hinge upon the prior days convection, so thus there is inherent uncertainty. Depending on where a low level warm front sets up, southern WI could see a couple rounds of thunderstorms early next week. Cronce && .AVIATION... Issued 325 AM CDT Tue Jul 15 2025 Some patchy fog across the Wisconsin river Valley early this morning. Otherwise, VFR conditions prevail today with some diurnally driven cumulus clouds (4-6kft) and southerly winds up to around 10 knots. Warmer temps will once again contribute to the development of a lake breeze, which could bring a brief period of gusty, southeasterly winds to the eastern terminals closer to the lakeshore between 18z-21z this afternoon. Light winds and VFR conditions persist overnight into Wednesday morning, but lower flight conditions along with shower/storm chances increase through the day Wednesday. Wagner && .MARINE... Issued 325 AM CDT Tue Jul 15 2025 Southerly winds continue to increase today into Wednesday as high pressure over the northern Ohio River Valley slides east to the Mid Atlantic States. Then looking at broad low pressure and a cold front to track across southern WI and lower half of Lake Michigan Wednesday through Wednesday night. Will see showers and thunderstorms accompany this low pressure as it pushes through the region. Cold front looks to push southeast of Lake Michigan later Wednesday turning winds to the north behind it. Northerly winds will persist into Thursday, but should gradually weaken and turn more easterly Thursday night into Friday as high pressure builds across the Upper Great Lakes. 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