A Case Study of the 30 June-1 July 2011 Lake Michigan-Crossing MCS
During this two-day period, three separate MCSs formed and regenerated along the western shore and directly over Lake Michigan. Forecasts predicted ~0.25 to 0.5 inches of rain, however, 6–8 inches accumulated in some localized areas. These systems resulted in over 17.5 million dollars in damage. A north–south-oriented warm front located directly over Lake Michigan served as a focusing mechanism for repeated convective development over Lake Michigan. Additionally, a robust low-level jet stream in the presence of significant low-level moisture and CAPE contributed to the heavy-precipitation event. Given the cool temperatures of Lake Michigan, the surface boundary was not well resolved by surface observations or numerical models, which likely contributed to the large forecast errors observed.