Mesoscale Discussion 1404 NWS Storm Prediction Center Norman OK 0409 AM CDT Tue Jun 25 2024 Areas affected...East-Central/Southern WI...Far Northern IL...Western Lower MI Concerning...Severe Thunderstorm Watch 455... Valid 250909Z - 251045Z The severe weather threat for Severe Thunderstorm Watch 455 continues. SUMMARY...Threat for severe gusts continues across southeast WI, with large hail more likely across far western Lower MI. Additional development is occurring across southwest WI and convective trends are being monitored for possible watch across southern WI and northern IL. DISCUSSION...Ongoing MCS has accelerated notably over the past hour or so, with storm motion now closer to 55 kt. The MCS has trended towards a more southerly motion as well, favoring now north-south oriented instability gradient. This more southerly motion may limit the chance that this MCS fully crosses Lake Michigan, with the strongest portion of the MCS potentially tracking closer to the southwestern shore of the lake. Strong gusts have started reaching the surface, with gusts of 55, 53 and 50 kt recently observed at SBM, GRB, and MTW, respectively. Potential for strong gusts is expected to persist within the line for at least the next few hours. Farther southwest, new thunderstorm development has occurred in the IA/WI/IL border intersection vicinity, within the core of the southwesterly low-level jet extending across the region. There appears to be some potential for additional development in southern WI, which would fill in the gap between these storms and the ongoing MCS. This scenario is uncertain, but could lead to am additional severe threat across southern WI and northern IL. As a result, convective trends are being monitored closely. Thunderstorms continue to intensify within the warm-air advection wing that is now over far western Lower MI. Primary threat with these storms is large hail, but a strong gust or two is possible as well. ..Mosier/Edwards.. 06/25/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...APX...GRR...GRB...LOT...MKX...DVN...ARX... LAT...LON 42919078 44978796 44568574 43048531 42458690 41978959 42919078