Seasonal and sub-seasonal predictions of tropical cyclones.

Accurate prediction of tropical cyclones (TCs) on seasonal and sub-seasonal timescales provides insights of TC activity a few months or weeks in advance to decision-makers to implement proactive and avoidance measures. This talk will start with an evaluation of the performance of dynamical models (GCMs) in predicting seasonal TC frequency in the West Pacific, and then provide a narratives of model deficiency by emphasizing the roles of large-scale atmospheric circulation. I will introduce a new statistical seasonal prediction method that was recently developed in collaboration with forecasters in Southeast Asia. The method outperforms existing dynamical and statistical predictions in terms of both lead time and skill. In the 2^nd half of my talk, the focus will shift to large-scale drivers of sub-seasonal predictability of TC occurrence, such as atmospheric equatorial waves. This will include discussions on leveraging the new knowledge to improve the sub-seasonal prediction of TCs in the future.