FXUS63 KMKX 040217 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 817 PM CST Tue Dec 3 2024 .KEY MESSAGES... - Scattered snow showers will be possible on Wednesday. These showers will be convective in nature and may feature some brief bursts of snow and low visibility. However, accumulations will be minor with any snow showers. - Strong southwest winds tonight into Wednesday morning and northwest winds Wednesday afternoon into Thursday will bring gale conditions to Lake Michigan. - The strong northwest winds Wednesday afternoon may exceed 45 mph. Secure loose objects. - Much below normal temperatures will return Wednesday night through Thursday night. Overnight wind chills will be in the negative single digits. && .UPDATE... Issued 817 PM CST Tue Dec 3 2024 Areas of low stratus have been developing this evening on the leading edge of 925 mb warm advection. The fcst soundings were showing the potential for this to occur, so would expect the stratus to gradually shift newd with time. Do have higher confidence for more widespread stratus after 12Z Wed with the passage of a sfc trough that will shift swly winds to wly. The arctic front is still on track for passage from 20-23Z Wed with gusty nwly winds to 40-45 mph and sct snow showers. Gehring && .SHORT TERM... Issued 256 PM CST Tue Dec 3 2024 Tonight through Wednesday Night: Surface low pressure will strengthen as it tracks from Manitoba to southern Quebec tonight through Wednesday. A potent clipper system will impact southern Wisconsin and the rest of the Upper Great Lakes region. We will see gusty southwest winds as the low approaches tonight into Wednesday morning, and very strong northwest winds and scattered snow showers in the wake of an associated cold front Wednesday afternoon through Wednesday night. Southwest winds will steadily increase through late evening in a warm air advection regime, peaking around midnight with the strongest vorticity advection with a leading shortwave trough. Winds will diminish a little Wednesday morning. The sudden cold air advection with the passage of the 850mb cold front may bring low clouds and possibly some drizzle. The low level temp profile during this period looks too mild for ice crystal development. Surface winds will be westerly during this time. By 3 pm Wednesday afternoon, the surface cold front will arrive in the northwest forecast area from the Dells to Madison and then barrel across the rest of southern WI through 6 pm. The biggest impact will be the strong winds. With the mixing potential up to 800 mb (or higher for a few models), wind gusts up to 39 kt/45 mph will be possible, which is the criteria for a Wind Advisory. Not enough models suggest higher than this speed, so we are not issuing a headline at this time. As far as the snow showers go, it will be blustery with snow falling, but amounts will be light. Forecast soundings are consistent across the models with temperatures well into the snow growth zone, and also with steep low level lapse rates. What the models disagree on is the depth of the moisture and the degree of the low level instability. With these uncertainties, I am not really confident in getting intense snow showers that would greatly reduce visibility and rapidly accumulate snow, despite the strong winds. The meso model forecast reflectivity usually can hint at the potential for stronger snow showers, and they are not showing this scenario for tomorrow afternoon. Visibility briefly down to 2 miles and a dusting of snow is what we are thinking for now. Temperatures will be "mild" tonight and Wednesday, but very strong cold air advection will drop temps down to around 10F and some single digits Wednesday night. With the wind gusts of around 30 mph, the minimum wind chills will be in the negative single digits. Cronce && .LONG TERM... Issued 256 PM CST Tue Dec 3 2024 Thursday through Tuesday: As low pressure continues eastward towards Maine and strong high pressure travels southeastward from the Dakotas into Iowa on Thursday, northwest winds with gusts upwards of 30 MPH continue, with wind chills in the negative single digits early in the morning. Mostly clear skies and dry weather expected Thursday, though forecast soundings show some potential for a few cirrus and cumulus clouds. Winds gradually decline in the afternoon and evening, becoming light and variable Thursday night as high pressure passes just south of our region. Overnight lows in the single digits to teens. Mostly calm, dry, and quiet weather expected Friday into the weekend. Lingering high pressure in the eastern CONUS and low pressure entering southern Canada will allow a southwest breeze to gradually moderate air temperatures, trending slightly above seasonal norms for the later half of the period. Early to mid next week would be the next noteworthy chance for precipitation, though it is too early to determine system track and precip type. Sheppard && .AVIATION... Issued 817 PM CST Tue Dec 3 2024 Areas of bkn010-019 stratus have been developing over srn WI early this evening. Do not expect the coverage to change until becoming widespread MVFR Cigs for the daytime hours of Wed. Breezy swly winds tnt will become wly by late Wed AM then nwly and even windier after 20Z Wed. Scattered snow showers along and behind the arctic front may briefly drop vsbys to 1-2SM Wed afternoon/early evening. Gehring && .MARINE... Issued 256 PM CST Tue Dec 3 2024 There were no changes made to the Gale Warnings for the open lake and Nearshore that are in effect. Southwest winds will increase tonight as low pressure over Manitoba deepens as it crosses Ontario tonight through Wednesday. Southwest gales are expected from late this evening through Wednesday morning as the low approaches. A lull in the gusts will occur as a cold front crosses Lake Michigan midday. Then a stronger period of high-end northwesterly gales is anticipated from late Wednesday afternoon into Thursday. Some isolated storm force gusts may occur, especially over the eastern half of Lake Michigan early Thursday morning. A Gale Warning is in effect for the whole lake to cover both periods of gales tonight into Thursday. Cronce && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 3 PM Wednesday. Gale Warning...LMZ643-LMZ644-LMZ645-LMZ646...3 PM Wednesday to 9 AM Thursday. Gale Warning...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until noon Thursday. && $$ 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