P24  Simulations of Lake-Effect Precipitation over the Great Lakes Using a Coupled WRF-Lake Model

Gu, Hongping, and Jiming Jin, Utah State University

In this study, the Weather Research and Forecasting (WRF) model coupled with a one-dimensional, ten-layer thermal diffusion lake scheme was used to investigate lake-effect precipitation over the Great Lakes region.  A five-year simulation was performed at 10 km resolution for the cold season from 2003 through 2008. Initial and lateral boundary conditions were provided by the six hourly, 32 km resolution North American Regional Reanalysis. The results show that the coupled model is able to realistically reproduce the observed precipitation over the areas strongly affected by lake processes. In addition, severe snowstorms occurring over or near the Great Lakes during the study period were selected based on radar reflectivity images and precipitation duration and intensity measurements from meteorological stations to examine the role of the lakes in triggering such storms. A composite analysis of low-level stability and vertical moisture transport for those lake-effect precipitation events are also presented here. Our results indicate that realistic lake process simulations are very important to accurate predictions of weather and climate in the Great Lakes region.