Seasonal forecasts: communicating current climate variability in southern Africa

Abstract

In southern Africa, seasonal rainfall and temperature forecasts have been made for almost two decades already and these forecasts have been developed to improve the ability of users to cope with fluctuations in rainfall and temperatures on a seasonal time scale. Seasonal climate forecasts are defined as probabilistic predictions of how much rain is expected during the season and how warm or cool it will be, based primarily on the principle that the ocean (sea-surface temperatures) influences climate and weather. Forecasts are usually issued for a period of six months and suggest the total amount of rainfall expected over that period, but not the distribution of rainfall within that period or the initiation of the rainy season. Similarly, seasonal forecasts give guidance on the temperature regime most likely to dominate during a coming season.