FXUS63 KMKX 300910 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 410 AM CDT Sun Jun 30 2024 .KEY MESSAGES... - River flooding and high water levels remain elevated into next week. Additional rises will be possible with any heavier rainfall. - A moderate swim risk is expected for the Lake Michigan beaches in Milwaukee County and a high swim risk is expected in Racine and Kenosha Counties tonight into Sunday. - Next chances for thunderstorms develop Monday into Tuesday. && .SHORT TERM... Issued 410 AM CDT Sun Jun 30 2024 Today through Monday: High pressure will continue to build into the Great Lakes Region from the Northern Plains today. The surface high pressure center is expected to be overhead of the state tonight into Monday morning. By Monday, night this high pressure will be exiting to the east and the synoptic scale subsidence will be clearing out of the state. With the high pressure overhead tonight, there will be a chance for some radiation fog development. Winds will be light and variable with clear skies. Not anticipating fog to become dense at this time, but low lying areas such as river valleys and marsh lands will have the best potential for any patchy dense fog. Breezy winds are expected over Lake Michigan into this afternoon due to the tighter pressure gradient between a low pressure system in eastern Michigan and the incoming high pressure from the Northern Plains. While the northerly winds over the lake will be able to be largely ignored by most people. Far southern Wisconsin lakeshore areas will have some impacts to their beaches. In particular, Racine county will be especially susceptible to high swim risk conditions because the geography of the lakeshore juts out to the east. Beach hazard statements are in effect for both Kenosha and Racine counties through this afternoon. Use extra caution today if you will be on Lake Michigan. Patterson && .LONG TERM... Issued 410 AM CDT Sun Jun 30 2024 Monday night through Saturday: As high pressure exits to the east Monday night, an incoming trough will bring a return to precipitation chances late Monday night into Tuesday. WAA will have been underway since mid Monday with the south to southeasterly winds. The moisture advection will prep the low and mid levels for storm development within and ahead of the warm sector for Tuesday. Guidance suggests the low level jet setting up across Wisconsin Tuesday morning/afternoon, which will provide some forcing for rain and storm development. With guidance being pretty consistent on the cold front moving through Tuesday night into Wednesday, there could be a potential for two "rounds" of precipitation. One within the warm sector and a second with the passage of the cold front. Its still a bit to early to really get into the specifics of timing, but if things begin to line up well and southern Wisconsin gets clearing skies there could be a good potential for some stronger storms. Instability will be the key player to keep an eye on. Behind the cold front Wednesday has the best potential for a brief period of dry weather, but timing and duration on this is uncertain. Another trough is expected to be right on the heels of the first, which will quickly bring additional chances for rain and storms. Guidance has this second trough holding off until Thursday. There is quiet a bit of variability in the timing and location of this low pressure system. The sfc low fluctuates locations between far northern Wisconsin to southern Wisconsin which would play a big roll in the anticipated rain potential. As things stands now there is a moderate potential for rain (around 40-50%) Thursday evening when sticking to the average among guidance. The holiday is by no means a wash out at this point, but its definitely a time where everyone will be looking at the forecast. So make sure to keep up to date with the forecast through the week. Beyond the holiday, the pattern continues to look active with additional troughs and shortwaves on the horizon. Long range guidance has quiet a bit of variability which has allowed some broad brush low chance POPs of 20-25 percent or less to be in place for Friday through Sunday. This will likely continue until guidance start to solidify and coverage toward a singular point later on. As mentioned a few times above there will be periods of ongoing WAA through the extended forecast. Ensembles pick up on this well and thus temperatures climb back up in the low to mid 80s for much of the extended. Patterson && .AVIATION... Issued 410 AM CDT Sun Jun 30 2024 VFR conditions are expected through this evening across southern Wisconsin. Clear skies tonight will persist through the morning until diurnal mixing increases. The diurnal mixing will cause some fair weather cumulus clouds to develop this afternoon. Cloud bases are expected to be around 4-6 kft through the evening. Tonight, winds will become light and variable under clear skies. There will be a chance for patchy fog to develop across southern Wisconsin during the overnight hours. Fog is currently not anticipated to become dense. Visibilities are expected to be around 2-6 SM. Any fog that develops will be burn off shortly after sunrise. Breezy north to northwest winds this morning will weaken this afternoon and evening. Light and variable winds are expected tonight into Monday morning. Southeast winds are in store for Monday and Monday night. Patterson && .MARINE... Issued 410 AM CDT Sun Jun 30 2024 Gusty north to northwest winds are expected today due to a tighter pressure gradient over the lake. This tighter pressure gradient between a low pressure system in eastern Michigan and the incoming high pressure from the west will shift easterly overtime today. A Small Craft Advisory is in effect through this afternoon for all nearshore waters. A beach hazard statement is in effect for Racine and Kenosha areas due to the breeze northerly winds. Winds will weaken tonight into Monday and become predominately easterly as high pressure around 30.3 inches builds in from the Northern Plains. High pressure will advect east of the Lake Monday night, causing winds to become southeasterly and increase. South to southeast will linger into Tuesday night, before a cold front moves east across the region. Patterson && .MKX WATCHES/WARNINGS/ADVISORIES... WI...Beach Hazards Statement...WIZ071-WIZ072 until 3 PM Sunday. LM...Small Craft Advisory...LMZ643-LMZ644 until 9 AM Sunday. Small Craft Advisory...LMZ645-LMZ646 until 3 PM Sunday. && $$ 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