Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
941 FXUS63 KMKX 032052 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 352 PM CDT Fri May 3 2024 .KEY MESSAGES... - A few stronger thunderstorms are possible in southeast WI Saturday afternoon. - Additional showers and thunderstorms are expected during the middle portions of next week. && .SHORT TERM... Issued 351 PM CDT Fri May 3 2024 Tonight through Saturday night: Clear skies will prevail over southern WI tonight. Look for winds to become light and variable overnight as high pressure moves across the region, then start increasing out of the southeast in the morning as the high departs. Dewpoints mixed down to around 40 this afternoon, so that should help our evening temps drop into the lower 50s quickly. Lows should be in the upper 40s, but can`t rule out mid 40s toward central WI. A line of showers and thunderstorms along a weak cold front will be tracking into the western part of WI Saturday morning. This front is associated with a mid level shortwave trough and the resultant weak surface low. The stronger forcing with that shortwave will stick closer to the entrance region of the upper jet, which will track across northwest WI. Therefore, the line of showers with a chance for lightning will be weakening as it tracks into south central WI late Saturday morning. Once the front reaches south central WI from around Janesville to Fond du Lac, there will have been enough daytime heating to allow for some build-up of CAPE (up to 1000 j/kg) in southeast WI to support an increase in shower and thunderstorm development. The shear is on the higher end and will be enhanced by the lake breeze. While the mid level forcing will be weaker, the surface forcing will be stronger. Thus, there is a chance for a stronger storm or two in far southeast WI during the afternoon. Small hail and gusty winds are the threats. The tornado threat is non-zero if storms interact just right with the lake breeze boundary. The window of opportunity looks like 3 to 8 PM for areas between Janesville, Port Washington, and the WI/IL border. Cronce && .LONG TERM... Issued 351 PM CDT Fri May 3 2024 Sunday through Friday: High pressure will take hold of southern WI Sunday and Monday. Look for increasing southeast winds Mon afternoon as low pressure approaches from the Plains. That closed low will stay fairly stationary in the Northern Plains Mon-Tue as it occludes, but showers and thunderstorms along the warm front should extend into southern WI on Tuesday. As the upper low either moves eastward or weakens, another round of showers and storms is possible over southern WI on Thursday. The weather pattern associated with the storm chances is complicated and unorganized, which is the typical nature of upper lows. Expect changes to the forecast many times between now and then. Unfortunately, that upper low does not move out of the Upper Midwest until at least Saturday, which means a prolonged period of clouds and precip chances for southern WI until then. Cronce && .AVIATION... Issued 351 PM CDT Fri May 3 2024 Winds will be calm overnight and start increasing out of the southeast in the morning as low pressure approaches from MN. A line of showers and thunderstorms will be weakening as it tracks into south central WI late Saturday morning. Once the associated front makes it to around Janesville-Fond du Lac, more widespread showers and thunderstorms are expected to develop. Areas southeast of Janesville to Port Washington have the best chance for stronger storms. Thunderstorm activity should exit the area by 10 pm (03Z), but probably earlier. Cronce && .MARINE... Issued 351 PM CDT Fri May 3 2024 Light southeast winds are expected tonight into Saturday as high pressure slides across the Upper Great Lakes. Showers and thunderstorms are possible along a cold front late Saturday afternoon through the evening. High pressure will return for Sunday and Monday. The next low pressure system that may bring gusty winds below gale level and another round of thunderstorms will track across northern Lake Michigan Tuesday into Wednesday. Cronce && .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