Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
047 FXUS63 KMKX 201931 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 231 PM CDT Fri Sep 20 2024 .KEY MESSAGES... - Summer-like temps to continue one more day on Saturday, but cooler/near normal temps are expected into next week behind a weekend cold front. - Additional showers and thunderstorms return Sat nt-Sun with smaller chances afterward. && .SHORT TERM... Issued 231 PM CDT Fri Sep 20 2024 Tonight through Sunday: A warm and drier airmass is now in place across srn WI which will greatly limit the fog potential for tnt, despite high pressure moving from IA into srn WI. Low temps mainly from 55-60F is forecast. Sly winds and warm, moist advection will then begin Sat afternoon as a n-s sfc trough/cold front approaches from the west. This front extends swd from a strong upper wave and well developed sfc low over Manitoba and Ontario. Sfc-850 mb dewpoints will surge back into the area from the sw while PWs rise to 1.5-1.7 inches for Sat nt-Sun AM. Negative showalter indices and marginal MLCAPE will develop by late Sat afternoon and evening. South central WI may see initial shower and storm development by mid to late afternoon, but with increasing chances through the evening and overnight for all of srn WI as the cold front passes. Continued or additional shower and isold storm development is expected on Sunday on the cool side of the exiting front via frontogenesis and the passage of a shortwave trough across nrn IL and far srn WI. Overall 0.5-1.00 inches of rain is forecast with the highest potential for 1 inch amounts toward the IL border. Gehring && .LONG TERM... Issued 231 PM CDT Fri Sep 20 2024 Sunday night through Friday: The passing cold front will stall along the Ohio Valley for early in the week while a couple shortwave trough in wswly flow move across the region. At this time it appears srn WI will be on the nrn periphery of the upper dynamics and lower level frontogenesis, hence just 20-40 PoPs at this time. The last shortwave trough will exit Wed AM with 500 mb height rises to follow as an upper ridge approaches from the nrn Great Plains. The upper ridge and sfc ridging will then prevail over the nrn Great Lakes for Thu-Fri. Temps will be near normal for this period but will likely trend above normal late in the week. Gehring && .AVIATION... Issued 231 PM CDT Fri Sep 20 2024 VFR conditions this afternoon through Sat evening other than a brief period of fog at sunrise Sat in the lower WI River Valley and other low lying areas. Showers and storms will increase in coverage from west to east across srn WI from late Sat afternoon into Sat nt as warm front moves into the region and is quickly followed by a cold front. Gehring && .MARINE... Issued 231 PM CDT Fri Sep 20 2024 A cold front will continue across Lake Michigan this evening. Thus light to modest southerly winds this afternoon will turn westerly this evening into the overnight. Weak high pressure will then move across the lake on Saturday with light and variable winds in the morning becoming southerly in the afternoon and evening. A Canadian cold front will then move across the lake Sunday morning with winds shifting to modest northerly for the afternoon, continuing into early next week. Gehring && .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