Seasonal forecasting of South African rainfall using a non-linear discriminant analysis model

Statistical models have been used to provide operational seasonal forecasts of rainfall over southern Africa since 1992. The Climatology Research Group has been using a quadratic discriminant analysis model since November 1994. The model relates rainfall over different areas of South Africa to principal components of sea‒surface temperatures in the Indian, South Atlantic and Pacific Oceans. Details of the model are described in this paper. High forecast‒skill levels can be achieved for much of the country throughout the year. The mostly successful performance of the model over a 15‒year independent testing period indicates that the model can be used successfully in an operational environment