Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
960 FXUS63 KMKX 291954 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 254 PM CDT Wed May 29 2024 .KEY MESSAGES... - Dry through Friday with cool nights in the 40s. - Periodic shower and thunderstorm chances return Friday night through Saturday and Monday through mid week. && .SHORT TERM... Issued 254 PM CDT Wed May 29 2024 Tonight through Thursday night: High pressure will drift overhead tonight. With clear skies, dry air and calm wind, strong radiational cooling will allow temperatures to drop into the lower 40s for inland areas. There is a lot of model agreement on these lows and no chance of getting lower than 39, per model guidance stats. The forecast for tonight is around the 25th percentile. There are frost concerns for northern Wisconsin. Dewpoints for areas inland from Lake Michigan but east of Madison should be in the mid 30s based on upstream obs in northeast WI. This will keep fog chances out of the forecast here. For areas west and northwest of Madison, the dewpoints should be a little higher and closer to the temps. Fog in the Wisconsin River Vally is likely, with some patchy fog possible northwest of Madison, especially in the Dells area. Plenty of sunshine is expected Thursday, with fewer clouds than today. Light southeast winds will develop in the afternoon as the high starts to depart. Highs Thursday should be a little warmer for far inland areas than today with that return flow around the high, so highs in the lower 70s. Thursday night will be one more cooler night with inland lows in the lower 40s. This forecast is on the lower side of guidance (25th percentile), so temps may end up being a few degrees warmer if the warm air advection kicks in a little earlier than expected and can overcome the radiational cooling. Cronce && .LONG TERM... Issued 254 PM CDT Wed May 29 2024 Friday through Wednesday: The weather is expected to be dry Friday. Look for increasing high clouds through the day as convection should be ongoing toward the MN/WI border, especially in the afternoon. An elongated, phased upper trough spanning from the Northern Plains to Oklahoma will push an area of showers and thunderstorms across the Plains tonight through Thursday. Strong ridging over the Great Lakes will help to diffuse that upper level energy as it juts out ahead of the parent upper low Friday, but remnant boundaries and surface convergence should help keep showers and storms developing in central MN and IA through the day. By Friday afternoon, it looks like the southern stream upper low will start to close off over Missouri and drifts east while the northern stream one hangs back toward North Dakota. So by Friday evening, there may be some remnant showers and/or thunderstorms that make their way into southwest WI. Models are leaning more toward a dry forecast for southern WI during this time. For the overnight into Saturday morning, the forecast MCS associated with the southern stream trough may try to sneak into southern WI and this chance is depicted by both the 12z GFS and ECMWF operational models. Chance for thunder during this time is low due to decaying convection. Saturday afternoon, the northern stream shortwave is expected to swing across northern WI. Remnant moisture and convergence from the departing system and the approaching trough may allow for scattered showers and perhaps a few thunderstorms. Details for this day are just not there yet so keep up with the forecast. Subsidence and brief ridging should keep Sunday dry for southern WI, although there is an outside chance for steep enough mid level lapse rates west of Madison to allow for some diurnal convection. Models are picking up on an MCS developing upstream Sunday and tracking through WI late Sunday night into Monday morning. Again, not a lot of confidence in this scenario yet, but the chance is there. A more robust shortwave trough is expected to cross the US/Canadian border near MN Tuesday evening. Thunderstorms with this system may extend all the way down through Iowa and could track into southern WI later Tuesday night or Wednesday morning. Cronce && .AVIATION... Issued 254 PM CDT Wed May 29 2024 Diurnal cumulus clouds with bases around 4500 ft will diminish as the sun sets this evening. Expect clear skies tonight with patchy fog possible north and west of Madison, especially in the Wisconsin River Valley. Fewer clouds than today are expected Thursday. Look for increasing east- southeast winds and increasing high clouds Thursday afternoon, but 10 kt or less. Cronce && .MARINE... Issued 254 PM CDT Wed May 29 2024 Winds will weaken overnight into Thursday as high pressure works its way across the Upper Great Lakes through Friday. Look for increasing southerly winds later Friday into the weekend as a low pressure trough approaches from the Northern Plains. Periods of showers and thunderstorms are looking more likely Saturday and Monday through Wednesday. Cronce && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ 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