Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
820 FXUS63 KMKX 121505 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 1005 AM CDT Sun May 12 2024 .KEY MESSAGES... - Very warm and breezy today. Scattered thunderstorms late this afternoon and evening. - Widespread rain with embedded thunderstorms Monday afternoon lingering into the evening mainly along and south of a line from Madison to Port Washington. && .UPDATE... Issued 1005 AM CDT Sun May 12 2024 The forecast looks on track the rest of today. Plenty of sunshine will contribute to building instability this afternoon, with isolated to scattered showers and storms still possible this afternoon as a weak shortwave rolls through. No significant updates to the forecast are anticipated the rest of today. DDV && .SHORT TERM... Issued 357 AM CDT Sun May 12 2024 Today through Monday: Light sly winds will develop early this morning becoming breezy swly winds this afternoon as a wave of low pressure moves across nrn WI. Low level warm advection will bring the thermal ridge into srn WI late in the day, and 925 mb temps will warm into the lower 20s Celsius. This will yield highs in the lower 80s for most locations. The breezy winds will mix out the dewpoints to some extent with dewpoint depressions greater than 30F for the afternoon. Thus Inverted-V soundings are expected for the afternoon and evening with MLCAPE of 500-1000 J/kg. Just small chances (20-30 percent) for storms for the afternoon as the cold front remains well to the north, but the convective temp could be reached. The wave of low pressure will weaken tnt as it moves east, thereby slowing the arrival of the cold front until sunrise Mon for the nrn CWA. However any storms along the front Sun afternoon and evening could propagate esely into srn WI especially toward central WI. Given the inverted-v soundings, gusty winds will be the main concern. For Mon-Mon nt, confluent flow is expected btwn an approaching weak shortwave trough from the nrn Great Plains, and a slow moving but larger shortwave trough tracking from the central Great Plains into IL. PWs will increase to 1-1.3 inches while frontogenesis, PVA and the right entrance region of a jet supports organized, deep lift. Thus expect showers and possibly a few storms to develop especially along and south of a line from Madison to Port Washington with much lesser chances for pcpn toward central WI. Gehring && .LONG TERM... Issued 357 AM CDT Sun May 12 2024 Tuesday through Saturday: High pressure noses in from the Hudson Bay on Tuesday and remains dominant through Wednesday, leading to cooler and dry conditions. Winds off Lake Michigan will lead to the coolest conditions in southeastern Wisconsin. A series of shortwaves then approach the area starting Thursday. Thunderstorms are possible Thursday afternoon as the first shortwave propagates southeastward. As this shortwave interacts with a southern Plains low, wrap around precipitation may continue across southern Wisconsin into Friday. The southern low looks to exit into Saturday, although an additional shortwave may approach from the Canadian Prairies Saturday into Sunday. Although there may be a dry period between Friday and Saturday, enough uncertainty in timing remains to keep 15 to 30 percent PoPs through the weekend. MH && .AVIATION... Issued 1005 AM CDT Sun May 12 2024 Breezy southwest winds are expected today, which should keep the lake breeze offshore. Isolated to scattered showers and storms are possible this afternoon into the evening, winding down early tonight. A stronger storm or two isn`t out of the question, particulary late afternoon and early evening. Widespread VFR conditions are expected to persist into at least early Monday. DDV && .MARINE... Issued 357 AM CDT Sun May 12 2024 Light south winds early this morning will become breezy south winds this afternoon as a wave of low pressure around 29.6 inches and its associated cold front moves across northern Wisconsin. The low and cold front will then slowly move across northern Lake Michigan tonight. Thus the winds will shift to light northwest late tonight over the north half, while modest southwest winds continue over the south half. The cold front will slowly move south on Monday bringing light to modest northerly winds to the entire lake. Breezy northeast winds and building waves will then develop over the south half late Monday night into Tuesday night as low pressure passes to the south, while high pressure extends from western Hudson Bay into Wisconsin. A Small Craft Advisory is in effect this afternoon and evening from Sheboygan to Winthrop Harbor for gusty sswly winds. Another Small Craft Advisory will likely be needed from early Tue AM into Tue nt due to persistent and brisk nely winds and building waves. Gehring && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...noon Sunday to 10 PM Sunday. && $$ 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