Impact of Lake Surface Temperature Variations on Lake Effect Snow Over the Great Lakes Region

Abstract

Abstract A high‐resolution three‐dimensional Weather Research and Forecasting (WRF) model is used to investigate the coupled impact of lake surface temperature (LST) and surface wind on the lake effect snow (LES) over the Great Lakes region. A set of twin WRF simulations, with and without resolving LST spatial variations in the model's surface boundary condition, is performed to quantify the impact of LST variation on LES. Both observations and model results reveal a positive correlation between the downwind LST gradient and surface wind convergence over the Great Lakes region. Furthermore, model simulations show that resolving the spatial variation of LST increases the surface wind convergence, correspondingly enhances local vertical motions in the atmospheric boundary layer, and creates favorable conditions for the LES formation on the lee sides of the Great Lakes. The contribution of LST spatial variations to the increase in precipitation on the lee sides of the lakes varies between 5% and 30% in individual LES events. The increase in the winter‐mean snow water equivalent due to LST spatial variations is between 3% and 15%. The most significant impact of LST variation on the winter‐mean snow water equivalent is on the lee side of Lake Huron.