Cold front acceleration over Lake Michigan

High-resolution Eta Model simulations of a strong but relatively dry late winter surface cold front that occurred during the STORM-FEST project depicted a pronounced acceleration of the front during the afternoon hours over the southern end of Lake Michigan. In this note, the impact of the lake on the front is examined. Reduced lower atmosphere turbulence due to both thermal stabilization and diminished surface roughness acting on postfrontal northerly winds increased frontogenesis strongly over the lake. The enhanced frontal circulation increased the front speed so that a noticeable frontal bulge occurred over the southern end of Lake Michigan. Some observational evidence is available to support the simulated frontal acceleration.