Under this award, Dr. Bromwich will systematically evaluate the ability of National Meteorological Center's (NMC) Medium Range Forecast (MRF) model to simulate the atmosphere in high southern latitudes and, based on that analysis, consider improvements to the model's boundary layer. This project represents a component of an international effort both to evaluate numerical weather prediction and to obtain a more detailed understanding of the meteorology of the region. The study will make use of the unprecedented quantity of data that will be acquired near Antarctica during the First Regional Observing Study of the Troposphere (FROST). The MRF's regional performance and biases will be compared to analyses of the FROST data. The evaluation will focus on precipitation processes and boundary layer structure. In addition, a series of sensitivity studies will be conducted with the MRF to evaluate the impact of the Antarctic observations and to test boundary layer parameterizations. This project will be conducted in collaboration with NMC staff as part of the NSF/NMC Joint Program in Numerical Weather Prediction. Improved forecast in this region would be of major benefit to operations in this region. The NSF support will be shared by the Polar Ocean and Meteorology Program.