The Impact of a Short-Wave Trough on Boundary-Layer Evolution during a Lake-Effect Snow Event
Sounding data taken during the passage of this first short-wave trough shows that the boundary-layer depth increased ahead of the trough passage both north and south of the lake-effect band. This boundary layer deepening resulted in a rapid increase in convective intensity. Following the short-wave trough passage, both the boundary-layer depth and the resulting convective intensity decreased. Furthermore, the short-wave trough had an influence on lake-effect snow maintenance in the presence of boundary-layer shear. Conventional wisdom suggests that boundary-layer directional shear in excess of 60° will destroy lake-effect snow. However, the lake-effect band reached its most intense stage as the short-wave trough approached and 60–80° of boundary layer shear was present. Likely, the approaching short-wave trough created a favorable dynamical environment, which allowed the lake effect to persist in spite of an unfavorable shear environment.