Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
694 FXUS63 KMKX 241418 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 918 AM CDT Tue Sep 24 2024 .KEY MESSAGES... - Showers for southeastern Wisconsin today with a small potential for heavy rainfall rates over the far southeast. - A small potential for waterspouts over southern Lake MI for today and tonight. - Mild and Dry conditions for Wed-Fri. && .UPDATE... Issued 918 AM CDT Tue Sep 24 2024 Shower chances will continue today across the eastern forecast area, as higher precipitable water values upwards of 1.5 inches linger. Still think there could be some locally heavy rainfall today, given the deep moisture, some instability, and the slow moving nature of this system. Planning on bumping up precip chances in the east for the remainder of the day given latest radar and model guidance. Otherwise, the forecast looks on track through the afternoon hours. DDV && .SHORT TERM... Issued 402 AM CDT Tue Sep 24 2024 Today and Tonight: A low pressure system is advancing toward southern Wisconsin today. This low is expected to pass through northern Illinois before moving northeast into southwestern Michigan. With the state on the northern side of low pressure system, expecting rain to move through the southern and eastern portions of the forecast area tonight through this evening until the low pressure system has moved out of the area. The best time for rain are expected to be this morning and early afternoon. Moisture advection is expected to wrap around the low pressure system as it advances northward which will moisten the mid to low levels, bringing PWATs up to around 1 to 1.5 inches. Along with the higher PWATs there is a chance for some banding to set up along mid level Frontogenesis which brings the potential for heavy rainfall. Far southeastern Wisconsin looks to have the best chances for the heavier rainfall. There will also be a small chance for a few rumbles of thunder again mainly across far southeastern Wisconsin where the support from the low pressure system is at its greatest for southern Wisconsin. Across Lake Michigan there is a chance for some waterspouts with the convective rain and thunderstorms early this morning through tonight. For more information on the waterspout potential be sure to check out the Marine discussion. Patterson && .LONG TERM... Issued 402 AM CDT Tue Sep 24 2024 Wednesday through Monday: Mid week and into the weekend high pressure/ridging will set up across the Great Lakes Region with an upper level low to the south (Rex Block Pattern). The low is expected to get cut off from the main flow as the ridge builds and strengthens, this will keep conditions dry and quiet across the state through the rest of the work week. From here we will look toward the development of a tropical system in/near the gulf. The strength and timing of this system will play a roll in how this blocking pattern breaks down for the weekend. Guidance has these two low pressure systems, one being the cut off low and the other being the tropical system, pivoting around one another as we head into Friday. Depending on how these two system interact we could see some precipitation advect up into the southern Great Lakes Region or stay further south and east. There is quiet a bit of uncertainty still in how this will evolve so stuck close to the average among model guidance through the weekend. Patterson && .AVIATION... Issued 918 AM CDT Tue Sep 24 2024 Lower ceilings and shower chances will linger today, especially east of Madison, as slow moving low pressure passes by to the southeast of Wisconsin. Some locally heavy rainfall will be possible across southeast Wisconsin. Skies will gradually clear out west to east tonight into Wednesday as the low departs and high pressure builds in from the west. Light north to northeast winds most places today (aside from breezier near the lake), will gradually become north to northwest tonight into Wednesday as the low exits the area. DDV && .MARINE... Issued 402 AM CDT Tue Sep 24 2024 Weak high pressure will remain northeast of Lake Superior while low pressure tracks from southern IL to southern lower MI today. This will bring the chance for thunderstorms and waterspouts over southern Lake MI. The low will also maintain modest east to northeast winds shifting northerly for tonight and Wednesday as the low moves away. Predominately north to northeast winds are expected across the lake until Wednesday when they briefly take on a westerly component. Light and variable winds are expected Wednesday night. The potential for waterspouts is expected to be across the southern half of the lake where there will be some convective rain and a few thunderstorms. The delta Ts between the water and 850mb is roughly around 10 to 15 degrees. The upper level low pressure is expected to dig southward moving toward the mid Mississippi Valley this morning before shifting eastward into the Ohio River Valley which puts the southern portion of the lake roughly in the northeastern quadrant as well, which can be a favorable zone for waterspout development this time of year. Even at the low moves eastward throughout the day any cloud depths that reach roughly 30 kft could pose a problem as well. A pretty dynamic situation for the southern half of the lake with the one main detriment being the 850 mb winds are a bit lack luster. The main take away from all of this is that where there are low clouds and rain, the chances for waterspouts will be likely throughout the day and into tonight. Patterson && .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