Mesoscale Numerical Weather Prediction

Mesoscale models, with grid resolution higher than synoptic and global models, and with advanced physical parameterizations, have been an important tool for meteorological research over the past twenty years. The research applications of mesoscale models, mostly through case studies or model sensitivity experiments in the 1980s, provided us with important physical insights into mesoscale weather systems such as the mesoscale environment of severe storms (Anthes et al 1982), tropical cyclones (Chang 1982), mesoscale convective systems (Zhang and Fritsch 1986), extratropical cyclones (Kuo and Reed 1988), and heavy rainfall events (Lee and Hong 1989). These mesoscale model applications typically use grid resolution ranging from 20 km to 100 km, generally within the range of grid resolution that does not violate the hydrostatic assumption. Because of the computational limitations, high-resolution mesoscale models were rarely used for real-time numerical weather prediction (NWP), and with a limited number of case studies, it is hard to know the performance and systematic behavior of these high-resolution models in day-to-day weather prediction.