Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
056 FXUS63 KMKX 291153 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 653 AM CDT Sat Aug 29 2026 .KEY MESSAGES... - Showers are likely at times today into tonight with slight chances for thunderstorms later today and tonight. - Becoming very warm and humid Sunday and persisting much of next week. There will be storm chances at times through at least the first half of next week. - A Small Craft Advisory may be needed late tonight into Sunday morning, particularly north of North Point Lighthouse. A Beach Hazard Statement may also be needed for Sheboygan and Ozaukee Counties. && .UPDATE... Issued 653 AM CDT Sat Aug 29 2026 Widespread rainfall to the west continues to approach the forecast area early this morning. This rain, which is largely associated with strong moisture and advection and warm air advection aloft, is expected to push through southern Wisconsin this morning into early afternoon. Models continue to show a lot of dry air below 700 mb, but should be enough forcing and moisture overall for rain to reach the ground. Precip chances were thus bumped up through the remainder of the day. The rain and clouds will also keep temps from warming much today, so also nudged highs downward. DDV && .SHORT TERM... Issued 1101 PM CDT Fri Aug 28 2026 Today through Saturday: Skies have momentarily cleared over srn WI but cirrus clouds upstream will move swd into srn WI during the overnight. Lgt sly winds will prevail at times through the night as the pressure gradient increases slightly due to a wave of low pressure moving ewd across the nrn Great Plains. Do not expect any organized areas of fog to form. For Saturday the shortwave trough currently over ND will round the ewd moving upper ridge and move across WI from late Sat AM through the afternoon. A well organized 700 mb baroclinic zone will accompany this feature with forecast soundings showing sufficient moisture and saturation for showers. PWATs will increase to 1.5-1.7 inches during the afternoon, but mid level lapse rates will remain poor, inhibiting most storm development. Rain chances of 60-80 percent are forecast along and north of a line from Dodgeville to Madison to Mequon but still 40-50 percent chances to the south. The shortwave trough will move away Sat evening but a swly 850 mb jet around 35-40 kts will veer slightly from central WI into srn WI through the night. The warm, moist advection will persist and support rain chances of 40-60 percent over ern WI with lesser chances over south central WI. Elevated CAPE will begin to gradually climb through the night as steeper mid level lapse rates arrive. The low level jet and associated thetae advection will still support sct showers and storms Sun AM, but mid level capping will then reduce or completely inhibit showers and storms for a time Sun afternoon and evening. The clouds and intermittent showers will keep temps down a bit on Sat, but the arrival of a warm front late Sat nt and Sun will boost high temps into the middle 80s with dewpoints approaching 70F for Sun afternoon. Gehring && .LONG TERM... Issued 1101 PM CDT Fri Aug 28 2026 Sunday night through Friday: A broad but low amplitude upper ridge will prevail over the central and srn USA through mid week with srn WI on the nrn periphery of the flat ridge. A swly low level jet will reside in the area from Sun nt-Tue nt, but the persistent moisture transport and weak warm advection will be offset by warm mid level temperatures. Thus shower and storms chances will range from 20-40 percent at times, but a more organized area of showers and storms may develop late Tue nt with the passage of a weak Canadian cold front. Cannot rule out some strong or severe storms as MUCAPE will rise to 2000 J/KG Mon-Tue with mdt deep layer shear in place. Very warm and humid conditions are expected through Wed then lessening for Thu-Fri as the upper ridge retrogrades toward the Great Plains and sfc ridging builds south from Canada. Gehring && .AVIATION... Issued 653 AM CDT Sat Aug 29 2026 Confidence continues to increase in a period of widespread rainfall this morning into early afternoon. Instability will be limited through the afternoon hours, so kept thunder largely out of the forecast. Dry air below 700 mb should result in ceilings staying VFR through the day, though visibilities could dip below 6SM at times with the rainfall. The rain will wind down west to east mid to late afternoon, with isolated to scattered showers then possible overnight into Sunday. A period of low level wind shear is likely tonight into early Sunday, as the low level jet moves overhead. Southerly surface winds 5 to 10 knots through tonight will pick up a bit from the southwest on Sunday. DDV && .MARINE... Issued 1101 PM CDT Fri Aug 28 2026 High pressure around 30.1 inches will gradually move east of the lower Great Lakes on Saturday, while low pressure deepens to around 29.6 inches in the central Great Plains. This will support modest to breezy southerly winds from Saturday afternoon through Monday as the low will remain well to the west. Scattered thunderstorms will occur at times from Saturday night into next week. A weak cold front will finally arrive late Tuesday night and Wednesday with light northerly winds eventually taking hold. A Small Craft Advisory may be needed north of North Point Lighthouse late Saturday night and Sunday if waves build to 3 to 5 feet. Gehring && .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