Mesoscale Discussion 0828 NWS Storm Prediction Center Norman OK 0546 PM CDT Sat May 18 2024 Areas affected...parts of central/northeastern Wisconsin into adjacent portions of Upper Michigan Concerning...Severe Thunderstorm Watch 257... Valid 182246Z - 190045Z The severe weather threat for Severe Thunderstorm Watch 257 continues. SUMMARY...Strong to severe thunderstorm development, including a few supercells posing a risk for severe hail and wind, probably will be maintained while spreading eastward across the region through around 8-9 PM CDT. DISCUSSION...Multiple discrete thunderstorms, including evolving supercells, are ongoing, emanating from a zone of stronger pre-frontal confluence across west central Wisconsin into the western Upper Peninsula of Michigan vicinity. Boundary-layer instability appears maximized along this corridor with mixed-layer CAPE on the order of 1000-1500 J/kg and renewed convective initiation remains possible another couple of hours as this zone shifts slowly eastward. Embedded within strongly sheared, 30-40 kt southwesterly deep-layer mean flow, storms have tended to propagate northeastward and eastward away from the initiating zone. Aided by the strong shear, these storms may continue to pose a risk for severe hail and locally strong gusts while spreading toward the Iron Mountain, Green Bay and Oshkosh vicinities through 00-01Z. While forecast soundings exhibit low-level hodographs potentially conducive to a a risk for tornadoes, it still appears this risk will be limited by sizable boundary-layer temperature/dew point spreads. ..Kerr.. 05/18/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MQT...GRB...MKX...ARX... LAT...LON 45868902 46428861 46008744 44678817 43778901 43609009 44288998 45358935 45868902