Expires:No;;874131 FXUS63 KMKX 061758 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1258 PM CDT Sun Apr 6 2025 .KEY MESSAGES... - A brief band of light snow will quickly move across southern Wisconsin early Monday morning, with additional scattered snow showers possible Monday afternoon. This will most be focused over east central WI where minor travel impacts are possible in the morning. - Below normal temps expected early next week, with highs rebounding to near & just above normal by mid-week. - The next disturbance approaches Wednesday through Thursday, bringing additional chances for mostly rain to southern Wisconsin. Precip could begin as a brief rain/snow mix Wednesday morning. - Temperatures continue to climb through the late week period. && .UPDATE... Issued 1258 PM CDT Sun Apr 6 2025 High pressure will shift south of srn WI this afternoon with wly winds becoming established, with the exception of the lake breeze in far ern WI. High temps in the lower to middle 50s away from the lake looks good for this afternoon. Otherwise the strong upper wave over wrn Ontario will dig and slightly amplify as it reaches east central WI by 12Z Mon. Modest cyclogenesis is expected from nrn WI to Lake Huron during this time with a strong cold front to shift swd across the region from 05-10Z. A narrow band of low to mid level saturation is expected although measurable precipitation will likely stay confined to east central WI where the upper dynamics are more focused. Nevertheless, a brief period of lgt rain changing to lgt snow is possible with 60 percent chances for east central WI. Very lgt snow accum is possible on grassy surfaces. The upper wave will then shift ewd across MI for the late morning and afternoon. Unstable but increasingly dry conditions are settling over srn WI for the late morning and afternoon with PWs falling below 0.20 inches. Forecast soundings produce very marginal CAPE with fairly high cloud bases expected over ern WI with just partly cloudy skies over south central WI. Isolated to scattered brief snow showers are forecast for ern WI into the afternoon with brief and minor visibility restrictions possible. Gehring && .SHORT TERM... Issued 443 AM CDT Sun Apr 6 2025 Today through Monday: Synopsis/Mesoanalysis: A surface pressure ridge is positioned across west-central Wisconsin this morning, resulting in light northwest surface winds and clear skies across the area. Evident in GOES water vapor imagery, a shortwave trough has been analyzed along the Manitoba-Ontario border. Said shortwave will progress southeast across Lake Superior today, promoting weak surface cyclogenesis in the Upper Peninsula of Michigan. The development of the surface low will allow winds to turn out of the west-southwest across southern Wisconsin this afternoon, bringing a modestly milder air mass in from the Northern Plains. The aforementioned shortwave will drive southeast into the region tonight as its attendant surface low moves into Lower Michigan. The low will concurrently drag a fast-moving cold front across southern Wisconsin during the predawn hours. Lift affiliated with the encroaching upper wave & elevated FGEN lagging behind the surface front will pull a quick-moving band of steady snow across the region from late tonight through the first half of Monday morning. Additional, more scattered snow shower potential will continue into Monday afternoon areawide. Minor/slushy accumulations will be possible on grassy surfaces, particularly across east-central Wisconsin. Combined with increasingly gusty north winds in the wake of the departing cold front, Monday's snow may result in minor travel impacts across southern Wisconsin. Be sure to allow for extra time if driving Monday morning and afternoon. Tonight Through Monday Morning: A quick-moving band of snow will progress across the area. Initial rain/snow mix can't be entirely ruled out along the leading edge of the band, though changeover to snow will occur rapidly. Snow potential will peak between ~1-5 AM north of I-94 & US-18, and between ~5-9 AM along/south of I-94 & US- 18. An overlap of pronounced 850-700 mb FGEN & weak CSI within a post-cold frontal/CAA regime will support the potential for elevated (0.5"+/hr) hourly snowfall rates within the snow band. While snow will be wet & slushy in character, said enhanced rates & increasingly gusty north winds could lead to reduced visibilities & minor travel impacts before & during the Monday morning commute. Budget a few minutes of extra time if planning to be on the roads. Given the potential for elevated hourly rates, anticipate that most/if not all minor snow accumulation from this event will occur during the morning snow band. Accumulations should be confined to grassy surfaces given mild pavement temps across the area. Best potential for slushy accumulations will be across east-central Wisconsin, where up to an inch may occur. Monday Afternoon: Confidence is increasing for additional, more scattered snow showers across all of southern Wisconsin. Thanks to a very cold air mass in the 925-700 mb layer, forecast soundings depict deeply-mixed boundary layers extending to near the 700 mb level. Given DGZ's residing between ~850-750 mb & LCL's rooted at/just below 850 mb, the aforementioned deep mixing/overturning would result in efficient ice nucleation within developing cumulus clouds, and thus the potential for hit/miss snow showers. Have accounted for this in the Monday afternoon PoP grids. Afternoon snow showers would be considerably drier & more powdery relative to the morning snow band, with still gusty north winds would make it easier for blowing snow & abrupt visibility drops to occur. Thus can't rule out continued minor/nuisance travel impacts into the Monday evening commute across southern Wisconsin. Will continue to monitor trends in the coming forecasts. Quigley && .LONG TERM... Issued 443 AM CDT Sun Apr 6 2025 Monday night through Saturday: Synopsis: Below-normal temps will persist through Tuesday as high pressure moves across the western Great Lakes. Winds will turn southerly and eventually southwesterly Wednesday-Thursday, allowing temps to climb back to or just above normal. The next upper disturbance & surface front will approach late Wednesday through Thursday, bringing the next chances for rainfall to southern Wisconsin. Temperatures will continue to trend upward through the late week period. Wednesday Through Thursday: The next chances for appreciable precip arrive with the next disturbance. Continue to see signals for mostly/if not all rain with this system given mild forecast temperatures. Will nevertheless be monitoring trends regarding the arrival of precip Wednesday, as a brief period of rain/snow mix could occur along the leading edge of precipitation. Could also see a few embedded thunderstorms given weak MUCAPE in global guidance, though strong/severe storms appear unlikely at the current time. Quigley && .AVIATION... Issued 1258 PM CDT Sun Apr 6 2025 VFR conditions this afternoon and evening followed by a strong cold front moving south across srn WI during the early morning hours. LLWS is forecast for the late evening into the overnight via a wly low level jet of 40 kt. A brief period of light rain and snow is possible especially toward east central WI, along with a brief period of MVFR Cigs and Vsbys. Isolated to scattered snow showers are then expected for the remainder of Monday but is expected to be light. Sct-bkn cloud cover with bases at 5-7 kft are forecast for the afternoon. Gehring && .MARINE... Issued 443 AM CDT Sun Apr 6 2025 Winds will briefly shift out of the west-southwest this morning and afternoon, when low pressure of 1012 mb is forecast to develop over the Upper Peninsula of Michigan. The low will progress across the northern open waters this evening as it deepens to near 1006 mb, moving into the Lower Peninsula of Michigan by daybreak Monday. Winds will shift out of the north to northwest behind the passing surface low late tonight through Monday, becoming gusty by late Monday morning. Widespread gusts between 25-30 knots are forecast through Monday afternoon, with periods of gale force gusts possible. Confidence in gales is highest across the southern half of the open waters, where a Gale Watch has been issued between 10 AM and 7 PM CDT Monday. Periods of snow will accompany the passing low, particularly tonight through the first half of Monday morning. A few areas of light freezing spray are possible late Monday afternoon into Monday evening, particularly across the northern half of Lake Michigan. Gusts will taper Monday night as 1022 mb high pressure moves into the western Great Lakes. In nearshore zones, north-northwest wind gusts and elevated wave heights will exceed Small Craft Advisory thresholds from late tonight through Monday night. Small Craft Advisories have been issued between 3 AM CDT Monday and 1 AM CDT Tuesday from North Point Light to Sheboygan, and between 5 AM CDT Monday and 7 AM CDT Tuesday from North Point Light to Winthrop Harbor. Winds and waves will taper comfortably below advisory levels Tuesday morning as high pressure builds into the Upper Midwest. Additional periods of Small Craft Advisory conditions are possible during the day on Wednesday, when low pressure will approach from the Great Plains. Quigley && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Small Craft Advisory...LMZ643-LMZ644...3 AM Monday to 1 AM Tuesday. Small Craft Advisory...LMZ645-LMZ646...5 AM Monday to 7 AM Tuesday. Gale Watch...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...10 AM Monday to 7 PM Monday. && $$ 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