Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
064 FXUS63 KMKX 192124 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 424 PM CDT Sun May 19 2024 .KEY MESSAGES... - Unsettled Monday and Tuesday with several rounds of rain/storms. - A slight risk for storms (2 out of 5) exists on Monday primarily over the southeastern corner of our CWA at this time. The main threats are gusty winds and hail. - Higher chances for severe weather appear possible on Tuesday with all modes of severe weather possible. There is a bit of uncertainty with this severe weather threat, however, as how storms overnight Monday into Tuesday evolve over IA/IL will determine how the environment evolves Tuesday afternoon and evening. && .SHORT TERM... Issued 400 PM CDT Sun May 19 2024 Tonight through Monday night: High pressure should keep things quiet this evening as high clouds stream in from the southwest. With time overnight, scattered shower and storm activity is expected to increase as low to mid level WAA increases over our region. Activity should congeal into a coherent blob and move east over our area around daybreak on Monday. By midday Monday, a remnant MCV from convection over KS will move through, providing an compact area of enhanced flow and PVA aloft. The MCV will spread over the area and steepen lapse rates, leading to SBCAPE around 1500 J/kg, and enhance effective Bulk shear to around 50 knots. Storm relative helicity is weak, dampening the tornado threat, but unstable and relatively dry low levels will support gusty winds, and any transient supercellular structures should support hail. Showers and storms should then exit after 7PM Following the MCV, subsidence should take over, suppressing widespread shower and storm activity, and only some very widely scattered showers may continue overnight. CMiller && .LONG TERM... Issued 402 PM CDT Sun May 19 2024 Tuesday through Sunday: Tuesday`s severe weather threat appears much more robust given the dynamics. Two waves at the 500mb level look to enhance flow over a warm front that`s expected to surge north with time Tuesday afternoon and evening as a sfc low deepens over Iowa and Minnesota. NAM/GFS/ECMWF solutions depict a moist, unstable environment with sickle hodographs, great low level instability, effective shear of 50 knots and favorable 0-3km shear of 50 knots as well. This type of environment would support supercells initially with upscale growth to a QLCS mode with time. Current timing for storms appears to be in the late afternoon into the evening. Some confounding factors appear to be the lack of jet dynamics aloft and the positioning of the warm front. The HRRR depicts convection exploding just south of the WI/IL border Tuesday morning. This scenario may limit the northward advancement of the warm front, but is an outlier for now. Once Monday convection shows its hand and we see more runs of the CAMs, we`ll have a better grasp of the severe threat on Tuesday. Beyond, the weather will grow quiet Wednesday into early Friday, before active weather returns next weekend. CMiller && .AVIATION... Issued 345 PM CDT Sun May 19 2024 Winds will grow easterly through the rest of the afternoon and evening as a lake breeze pushes in land. Clouds bases will generally remain VFR overnight but should begin to lower as shower and thunderstorm chances increase during the early morning hours mainly toward southwest to central WI. By daybreak on Monday, MVFR should move in from KMSN and points west amid breezy southerlies to 15 knots. Winds should become southwesterly Monday afternoon with chances for thunderstorms increasing over the south central to southeastern portions of Wisconsin. CMiller && .MARINE... Issued 340 PM CDT Sun May 19 2024 Light and variable winds will continue over the lake through the rest of the afternoon and evening as high pressure moves northeast. Winds will then come around to southeasterly by daybreak on Monday and should become more southerly by Monday afternoon. Breezy southerly winds will remain Monday night into Tuesday morning before winds become southeasterly ahead of a low pressure system that will deepen as it approaches the Upper Great Lakes Region. Periods of thunderstorms are also expected over the lake Monday through Wednesday morning. CMiller && .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