Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
579 FXUS63 KMKX 030207 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 907 PM CDT Wed Jul 2 2025 .KEY MESSAGES... - There are chances for thunderstorms Thursday afternoon and night. Gusty winds may occur with any stronger storms. - Very warm and humid conditions for Independence Day and Saturday, with heat index values in the middle to upper 90s. - Better chances for thunderstorms late Saturday into Saturday night, perhaps lingering into Sunday. Locally heavy rainfall is possible. && .UPDATE... Issued 907 PM CDT Wed Jul 2 2025 Convection continues to slide southeastward across southern Lake Michigan this evening, with outflow pushing southwestward across the region. Some isolated additional development is possible over the next hour or two, but with sunset, but things should be on a downward trend. Boxell && .SHORT TERM... Issued 310 PM CDT Wed Jul 2 2025 Tonight through Thursday night: Observing some scattered development of thunderstorms over northeastern WI at the moment, most likely associated with a weak zone of confluent surface flow and attendant 500mb thermal ridge. These features (as well as the thunderstorms themselves) are expected to track southeastward with the steering-level flow over the next few hours. For the few weak towers of cumulus trying to initiate convection overhead, I can only afford 10 to 15% precipitation chances at the moment (it would be isolated at best later this afternoon and evening). I have slightly higher (25%) chances for precipitation in east-central wisconsin (towards Sheboygan) later this afternoon / early this evening to account for the convection to our north grazing by. Both the diurnal cumulus clouds and the thunderstorm chances will decline as the sun sets this evening, with dry weather expected late tonight into Thursday morning (only 5-10% chances for a stray weak storm). For Thursday, a warm front progressing northward through the region will lead to slightly higher (15-30%) chances for thunderstorms, mainly from 1 PM CDT and onwards into Thursday night. Storms would be relatively brief and isolated (scattered at best), and if one or two of them were to phase perfectly with daytime heating (and fire in the mid afternoon through early evening), some gusty winds would be possible. Considering that, just a level 1 out of 5 severe threat. A lake breeze is not guaranteed on Thursday, but most models do allow one to form and push it at least 1 county inland (with easterly winds behind it). Light southwesterly surface winds (behind the warm front, further inland) will attempt to counteract this lake breeze. Sheppard && .LONG TERM... Issued 310 PM CDT Wed Jul 2 2025 Friday through Wednesday: Main story for Independence day and Saturday is the heat, with daytime high temps around 90 / low 90s and heat indices in the upper 90s expected. A modest south-southwesterly breeze is expected Friday, and is expected to mostly counteract the lake breeze (though the immediate vicinity of the Lake MI shoreline could see some ventilation from due south winds over the lake). Otherwise, it should be hot region-wide. Not expecting any thunderstorms / precipitation on Independence day (15% chance or less). The instability to fuel a storm will be present, but we lack any meaningful perturbation to initiate convection. Saturday`s southwest wind field should become strong enough to prevent the lake breeze, and may become gusty (currently forecasting 25 MPH gusts). Better chances for showers and thunderstorms arrive late Saturday into Saturday night as the low pressure system and cold front approach from the west (30-60% chances). Front-parallel wind shear and PWAT values approaching 2 inches would suggest a threat for training convection and localized heavy rainfall. 40-50% shower and thunderstorm chances linger into Sunday on account of the continuation of the cold front passage (ECMWF solution) or wrap-around showers on the back side of the low (other model solutions). Sheppard && .AVIATION... Issued 907 PM CDT Wed Jul 2 2025 For the rest of this evening, outflow pushing westward and southwestward from thunderstorms that occurred earlier will result in erratic winds at times, with short periods of gusty northeast winds immediately behind the outflow boundary. Isolated thunderstorms should remain east of the terminals at this point. Winds will return to light westerly overnight, becoming more southwesterly with time on Thursday. Isolated thunderstorm development is expected Thursday afternoon, with more widespread convection possible late Thursday night into early Friday, though these chances remain uncertain. Boxell && .MARINE... Issued 310 PM CDT Wed Jul 2 2025 High pressure around 30.0 inches will linger across the Middle Mississippi River Valley today into Thursday, before moving to the east by Friday. Light southwest to west winds will continue today into tonight. Light north to northeast winds Thursday into Thursday night will shift south to southwest on Friday, as a warm front moves north through the region. South to southwest winds will then increase Friday night into Saturday night, as low pressure around 29.6 inches moves across Lake Superior and Ontario and pulls a cold front through the region. Expecting west winds behind this front on Sunday, veering north into Sunday night. There will be small chances for showers and thunderstorms at times this afternoon and evening, mainly over the northern half of the lake. Additional small chances Thursday afternoon through Thursday night, focused on the southern half of the lake. More widespread chances for showers and thunderstorms expected later Saturday into Sunday as the cold front crosses the lake. Sheppard && .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