Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
921 FXUS63 KMKX 260842 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 342 AM CDT Thu Sep 26 2024 .KEY MESSAGES... - Milder and dry conditions prevail today through Friday. - Hazardous swim conditions may return to Milwaukee county beaches and south Friday evening into Saturday. && .SHORT TERM... Issued 340 AM CDT Thu Sep 26 2024 Today through Friday night: High pressure sliding over southern WI with a building upper- level ridge axis over the Upper Midwest will result in calm winds, dry conditions, and warmer temps today. Looking at high temps this afternoon in the mid to upper 70s, but given the ample sunshine plus previous day temp trend above the NBM mean and forecast, would not be surprised to see a few sites crack the 80F this afternoon. Influence from high pressure and subsidence will linger overnight Thursday and will see overnight temps dip into the 50s. Meanwhile, the upper-level cutoff low meandering over the Ohio River Valley today will persist. By Friday all the models prog the remnants of the tropical system, Helene, to track up the southern Appalachian Mountains before being picked up by the upper-level trough and wrapped back to the west. The center of the sub-990mb low continues to remain south of our area, but the tighter pressure gradient on the northern peripheral of the low looks to graze southeastern WI and push the surface high to the north and east of the area. While not expecting the heavy rainfall from the remnant tropical system to make it into southeastern WI, there will be low end <30% chance for some showers. Additionally this system may bring stronger northerly winds off of Lake Michigan Friday afternoon through the evening and may result in increased swim risk conditions for Milwaukee county beaches and south. Wagner && .LONG TERM... Issued 340 AM CDT Thu Sep 26 2024 Saturday through Wednesday: Influence from the north side of the Ohio River Valley low will linger into Saturday, but the upper-level trough is progged to gradually slide eastward Saturday into Sunday. The flattened upper- level ridge then begins to restrengthen more into Sunday and Monday with surface high pressure sliding down across upper Great Lakes Region. Should see seasonal temps through the weekend into the start of next week with highs in the 70s. However, the trend for a cool down continues for Tuesday onward. The long range models are still in fairly consistent agreement with a series of upper-level troughs digging across the Upper Midwest and bring a pair cold fronts across WI Tuesday and again sometime around Thursday/Friday with reinforcing high pressure helping a cooler Canadian airmass to settle over the region for the start of October. Wagner && .AVIATION... Issued 340 AM CDT Thu Sep 26 2024 With the exception of fog development in the Wisconsin River Valley and patchy ground fog for inland terminals, light winds and VFR conditions will prevail across southern WI this morning and through the period as high pressure moves overhead. The high depart to the northeast overnight and may see some patchy fog development again for low-lying areas. Will begin to see high clouds spread in heading into Friday morning ahead the remnant tropical system working its way into the Ohio River Valley. Wagner && .MARINE... Issued 340 AM CDT Thu Sep 26 2024 High pressure will work its way across WI today before lifting northeast across Lake Michigan into Friday. This will result in light and variable winds across the Lake through Friday morning. However, as a deep low pressure from the remnants of the tropical system, Helene, lifts up across the Ohio River Valley, expect a tighter pressure gradient on the northern edge to clip southern Lake Michigan. This will result in stronger northeasterly winds and may even see an occasional gust to gale force in far southern portions of Lake Michigan Friday afternoon and evening. Thus likely will see some small craft conditions as well fro nearshore zones south of Milwaukee. Then expect high pressure to return for the latter half of the weekend into the start of next week with lessening northeasterly winds. Wagner && .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