MCS organization and development along land/lake-induced thermodynamic boundaries near the Great Lakes

Horizontal potential-temperature gradients near the periphery of large lakes can play an important role in the formation and evolution of severe weather-producing mesoscale convective systems (MCSs). These mesoscale, thermodynamic boundaries often form during the warm season near the shores of the Great Lakes due to differential heating of the land and lake surfaces. An intense land/lake boundary can combine with synoptic features favorable for convection (e.g., a low-level jet and upper-level divergence) to enhance local forcing for ascent, which can in turn induce convection and MCS organization near the lake. This study will focus on a radar climatology, composites, and observational and WRF-simulated case studies which elucidate pathways for MCS organization and development near the Great Lakes during the warm season.

The climatology and composites will highlight some of the most important conditions for MCS initiation near the Great Lakes, including the magnitude and location of the surface boundary and the presence of a low-level moisture source. Then, case studies and high-resolution model simulations will illustrate the importance of and interactions among the land/lake surface boundary, the magnitude and direction of the low-level jet and wind shear, and the prevailing synoptic environment upon the formation of severe weather-producing MCSs. These results will show that accurately resolving near-surface boundaries and features is especially important for proper diagnosis and prognosis of near-lake MCS development.