Trends in seasonal forecasting of tropical cyclone activity

This paper presents a review of the development of Seasonal Tropical Cyclone Forecast Models (STCFM) for the western north Atlantic, Australian and western north Pacific Ocean basins. Current hypotheses on the climatic controls affecting the interannual variability of tropical cyclone activity are described. Although doubt remains concerning the correlation between El NiñoSouthern Oscillation (ENSO) and the yearly frequency of tropical cyclones in the western north Pacific, much of the interannual variability of cyclone activity in the western north Atlantic and Australian basins can be explained by ENSO and related phenomena. An association between the Quasi-Biennial Oscillation and hurricane activity has also been well established for the western north Atlantic, but not for the Australian and western north Pacific basins. A rigorous evaluation of seasonal hurricane forecasts in the western north Atlantic is described. It is proposed that future research focus on: (a) more appropriate statistical methodologies, and (b) the physical relationships between tropical cyclone activity and possible new seasonal predictors.