FXUS63 KMKX 262007 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 307 PM CDT Tue Sep 26 2023 .SHORT TERM... (Issued 307 PM CDT Tue Sep 26 2023) Tonight through Wednesday night: The forecast in a nut shell has scattered rain and thunderstorms chances continuing across southern Wisconsin through Wednesday night. Then warm and dry weather will be in store Thursday through early next week. A low pressure system is very slowly moving across eastern Iowa toward northern Illinois. This low pressure system will continue to weaken as it moves across far southern Lake Michigan into Indiana Wednesday evening. As this system moves eastward, we can expect a continuation of the conditions we have seen over the last 24 hours. Bands of showers and a few embedded thunderstorms will line up across much of Wisconsin and Illinois. This will result in on again off again rainfall. This pattern is expected to continue through much of the day Wednesday. By Wednesday night, the better moisture and lift will be moving east out of the state bringing an end to our rain chances. Heavy rainfall rates will be possible through tonight. There is a large warm cloud depth and high PWATs across southern Wisconsin which brings concern for 1-2 inch per hour rainfall rates. This could lead to some localized flooding tonight, especially for areas that have already received 2-4 inches of rainfall today. Urban areas and places with poor drainage will potentially have issues under those higher rainfall rates as well. Strong to severe storm potential is very low through tonight as there is very limited CAPE to work with and the little in the way of helicity/shear. Granted this is a similar risk to the previous day. So the best chances overall are along our southern tier of counties (the WI/IL border). The main risk with any storm that does get stronger would be a potential funnel or even a brief tornado. Lastly winds are expected to become gustier tonight with gusts up to 25 knots expected. This will cause waves to build across our nearshore waters resulting in a High Swim Risk and Small Craft Advisory this evening through Wednesday evening. Patterson && .LONG TERM... (Issued 307 PM CDT Tue Sep 26 2023) Thursday through Tuesday: With the cut off low pressure continuing its journey east, weakening along the way. High pressure will begin to take over of much of the central and eastern CONUS. This large area of high pressure looks to dominate through the weekend and into next week. Low pressure is expected to sit over the Rockies during much of this time, which will result in persistent southerly winds and some WAA. The WAA will give southern Wisconsin another weekend of summer like weather with warm, dry days. Day time highs are expected to climb into the mid to upper 70s. Its not out of the question for a few areas to even hit 80. Confidence is high on this ridge building and expanding across the region. It is unlikely that there will be any ridge running disturbances that would be able to bring any precipitation to southern Wisconsin during this time. Patterson && .AVIATION... (Issued 307 PM CDT Tue Sep 26 2023) Largely MVFR to IFR conditions across southern Wisconsin through this evening. Tonight, there will be a chance for some LIFR ceilings to develop, with the greatest chance for some LIFR conditions across western Wisconsin. Rain and storm coverage has become scattered this afternoon. Rainfall coverage is expected to increase again this evening and overnight. The chances for thunder and lightning will be low across the area with the best chances along the Wisconsin and Illinois border. With the moderate to heavy rainfall, visibilites are expected to range from 2-5 SM. Any prolonged breaks in rainfall will result in higher visibility. Winds will be out of the east through the period with gusts of 15-20 kts possible. Any brief modifications of the wind field may be induced by the heavier showers/storms as they pass by. Patterson && .MARINE... (Issued 307 PM CDT Tue Sep 26 2023) High pressure of 30.6 inches over the Hudson Bay will slowly weaken and drift south through Wednesday, while weak low pressure around 29.8 inches over eastern Iowa will shift east across northern Illinois. Moderate east winds will continue through Wednesday between these two systems, with rounds of showers, especially across the southern half of the lake. A Small Craft Advisory is in effect from this evening into Wednesday evening due to the easterly winds gusting near 25 kts and waves increases to between 4-6 feet. Thursday onward will see the return of dry weather. Light southeast to east winds will prevail across the lake into early next week. Patterson && .MKX WATCHES/WARNINGS/ADVISORIES... WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066-WIZ071- WIZ072...10 PM Tuesday to 10 PM Wednesday. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...10 PM Tuesday to 10 PM Wednesday. && $$ 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