Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
098 FXUS63 KMKX 231507 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1007 AM CDT Sat Aug 23 2025 .KEY MESSAGES... - Much cooler, less humid, and breezy from later today into early next week. - Some waterspouts are possible Sunday into Monday across Lake Michigan. && .UPDATE... Issued 1000 AM CDT Sat Aug 23 2025 Breezy northwest winds have arrived behind this morning`s cold front, and will continuously deliver lower and lower dewpoints to the region throughout today. The existing stratocumulus clouds gradually elevate from 2,000 to 5,000 ft altitude, dry weather continues. No major changes to the going forecast. Sheppard && .SHORT TERM... Issued 431 AM CDT Sat Aug 23 2025 Today through Sunday: Some scattered to isolated showers have developed out ahead of the cold front early this morning along a sfc trough. This broken line of showers will continue to move southeast out of southern Wisconsin before the sun rises. The surface cold front is still hang back a bit across central and northeastern Wisconsin roughly along a line from Iron Mountain to Stevens Point to La Crosse. The showers and a few storms have latched onto this sfc trough and this will is the "show" for the morning rain. Many of these showers developed overhead from roughly 1-3 AM so some areas across west central Wisconsin might not have gotten much if any rain. The cold front will continue to move southeast through the rest of the morning and winds will shift to northwesterly behind the front. Can`t completely rule out some drizzle along the front. On satellite you can see a thin line of clouds along the convergence zone of the front, but there`s very little in the way of good lift or instability so convergence is very low around 10% or less for any additional rain/drizzle. Dry weather is expected through the rest of the day with some brisk northwest winds and partly cloudy skies. As the low pressure system in northeastern Ontario deepens/strengthens, the pressure gradient will tighten over the Great Lakes Region. This will result in the breezy/brisk winds. Cold air advection will be underway as winds increase leading to cooling temps. Highs are expected to climb into the low to mid 70s with overnight lows dropping into the 50s. For Sunday, Wisconsin will remain under cyclonic flow with the deepening low in Ontario. This will maintain the northwest winds, CAA, and could potentially give us some low chances for drizzle/light rain. These chances are very low for much of the CWA around 10-20%. Chances will increase as you head north into northeastern Wisconsin where there is some higher confidence on a shortwave moving through the upper level flow provide some decent lift. Otherwise, majority of the area will remain dry with highs in the upper 60s to low 70 and overnight lows in the mid 40s to mid 50s. Lakeshore areas will be more insulated due to the warmer lake temps in comparison to inland areas. Patterson && .LONG TERM... Issued 431 AM CDT Sat Aug 23 2025 Sunday night through Friday: Northwesterly winds will continue through Sunday night as low pressure continues to occlude in the James Bay area, bringing in cooler temperatures as high pressure pushes southward from Canada into the northern Plains. A nose of high pressure propagating eastward into the southern Great Lakes region will prevent additional shortwaves from rotating through the flow into southern Wisconsin, and therefore should keep conditions dry on Monday and through the remainder of the work week. Expecting lows in the mid to upper 40s Sunday night through Tuesday night, with highs in the upper 60s Monday and Tuesday. Temperatures rebound into the 70s Wednesday through Friday as high pressure exits to the east. A backdoor cold front behind the exiting surface high may bring the next chances for precipitation going into Friday. MH && .AVIATION... Issued 1000 AM CDT Sat Aug 23 2025 The existing post cold front stratocumulus clouds have been a bit lower based than previously anticipated (down to 1,200 ft in some instances) but are still forecast to lift closer to 5,000 ft throughout the day. Hence, a few pockets of MVFR Cigs over the next few hours, becoming predominantly VFR into this afternoon. Breezy northwest winds today, with gusts around 20kt expected. Dry weather continues. 5,000 ft stratocumulus clouds may decrease in coverage into tonight, though forecast soundings indicate they could linger (at or just above that same altitude) into tonight. Winds remain northwest, but loose gusts after sunset. Sheppard && .MARINE... Issued 431 AM CDT Sat Aug 23 2025 Early this morning a cold front will pass from the northwest to the southeast bringing some scattered showers and a few thunderstorms. Winds will shift to northwesterly behind the front. A low pressure system in northeastern Ontario will strengthen to around 29.5 inches today into Sunday, bringing a tightening pressure gradient and brisk winds. Wind gusts around 20 to 25 knots will be possible across the open waters of the lake during the afternoon and evening hours. Nearshore waters will be teetering on the edge of Small Craft Criteria gusts this afternoon. Its unclear if the stronger winds up to 22 kts will actually mix down to the sfc and impact any Small Crafts. Winds are expected to be the primary concern as northwest winds will keep waves from building in the nearshore. Will continue to monitor winds over the water through the day. Beyond sunset winds will slightly weaken before becoming brisk again Sunday afternoon. A Small Craft Advisory may be needed Sunday as well. The light to moderate Northwest winds will continue through Tuesday. There will be a potential for waterspouts across all of Lake Michigan Sunday and Monday, as enough low level instability with favorable delta T values within the cyclonic flow aloft help support the waterspout risk. The northern half of the lake has the best potential, particularly on Sunday, and that threat will expand to the entire lake Sunday evening/night persisting through Monday. Patterson && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, X, and YouTube at: www.facebook.com/NWSMilwaukee www.x.com/NWSMilwaukee www.youtube.com/NWSMilwaukee