FXUS63 KMKX 191656 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 1156 AM CDT Tue May 19 2026 .KEY MESSAGES... - Diminishing chance for showers with the cold frontal passage today. - Cool and drier weather then returns for midweek. - Rain chances return Friday into Friday night(40-60%), followed by a gradual warming trend Saturday into early next week. && .UPDATE... Issued 1156 AM CDT Tue May 19 2026 The cold front is apparent on radar and is trekking through south central WI right now. It is almost to Madison. Sprinkles or a light shower are possible along the front. Then expect a wind shift to the west-northwest behind the front, with gusts up to 25 mph (not a lot different than the gusts going on right now). There are plenty of clouds upstream due to the diurnal influence, so expect these to thin out overnight. Lows will be in the lower-mid 40s tonight. Cronce && .SHORT TERM... Issued 1134 PM CDT Mon May 18 2026 Tonight through Thursday night: The decaying MCS is now moving into sw WI and will continue to encounter much greater MLCIN and high LFCs. However, still expect fairly widespread showers and sct storms to move across all of srn WI during the early morning hours as a sswly low level jet of 40 kts increases warm, moist advection and boosts elevated CAPE to 1000-2000 J/KG. Wind gusts and small hail will be the main concerns. A wave of low pressure along the stationary front from central IA to ern MN will track newd to near Lake Superior by 12Z Tue. The low will then track ewd into Quebec during the day with its trailing cold front moving across srn WI Tue AM into the early afternoon. Moist low levels and marginal instability could result in a broken line of showers and isold storms along the front but no severe wx is anticipated. Nwly winds and cold advection will continue into Tue nt with low temps falling into the lower to middle 40s. High pressure will then move from MN to the nrn Great Lakes on Wed and remain there into Thu. Nely sfc winds and a relatively cool air mass will reside over srn WI with high temps in the 50s over ern WI and lower 60s over south central WI. A return of warm advection will bring 20 percent chances for showers west of Madison Thu nt. Gehring && .LONG TERM... Issued 1134 PM CDT Mon May 18 2026 Friday through Monday: Low pressure ejects from the Southern Plains on Friday, with continued model discrepancies as to its progression. Canadian and Euro indicate a more southerly track of a single low pressure system bringing widespread rain and storms to southern Wisconsin throughout the day along the northern side of the low, while the GFS prefers a split pattern with one portion of the energy progressing through the lower Mississippi Valley and the other following the jet stream into Minnesota and brings a warm front with rain and storms into southern Wisconsin. Regardless of solution, probabilities of seeing rainfall have increased, so kept likely PoPs (50-65%) in the forecast for Friday afternoon into Friday night. Models also are inclined to agree that precipitation will taper off into Saturday as the warm front lifts north or the low pressure system exits to the east. Generally unsettled weather looks to develop Sunday through Tuesday as broad 500 mb troughing develops across the Upper Midwest, bringing multiple shortwaves through the region. As the upper level troughing develops, high pressure building in the Plains will bring increasing temperatures through the weekend into early next week. Monday and Tuesday temperatures could return to the mid-80s. However, weak, generally southeasterly winds will allow for Lake Michigan influence on temperatures in the easternmost counties. MH && .AVIATION... Issued 1156 AM CDT Tue May 19 2026 Expect MVFR ceilings ahead of and behind a cold front that is currently crossing southern WI (now near Madison). Breezy southwest winds will become west to northwest winds behind the front this afternoon and evening. Ceilings should lift to VFR late this afternoon and then disperse tonight as skies gradually clear as high pressure works into the region. Clouds below 5000 ft should be present on Wednesday, especially closer to Lake Michigan. Wind should be out of the northeast near the lake and then the northeast winds will expand inland through early afternoon. Cronce && .MARINE... Issued 1156 AM CDT Mon May 18 2026 The Marine Dense Fog Advisory for the north half of Lake Michigan was extended through mid afternoon due to relatively mild and humid air flowing over the cold lake waters. Fog will linger until the cold front moves through.Otherwise modest to breezy southerly winds will persist ahead of the front, then shift to the west-northwest and remain breezy through most of tonight. High pressure around 30.4 inches will then move into the northern Great Lakes for Wednesday afternoon into Thursday. Light to modest north to northeast winds can be expected. A Small Craft Advisory is in effect from Sheboygan to Winthrop Harbor through late afternoon for breezy southwest to west winds. Cronce && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 4 PM Tuesday. Dense Fog Advisory...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ868 until 3 PM Tuesday. && $$ 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