NCEP global ensemble prediction of tropical cyclone genesis over the East Atlantic: Evaluation during AMMA

This study evaluates the NCEP global ensemble forecast system in its performance of predicting the genesis and evolution of five named tropical cyclones and two unnamed non-developing tropical systems during the African Monsoon Multidisciplinary Analyses (AMMA). Firstly, a tropical cyclone tracking method has been developed to effectively track the storm development. Various tracking methods with different variables and vertical levels are compared. The overall skill of ensemble forecasts, ensemble means and spreads, and probabilities in both pre-genesis and post-genesis stages are evaluated. Additional comparisons have also been made to the high-resolution GFS model to determine to what degree the ensemble forecasts add value over the deterministic forecasts.

This work presents a first set of comprehensive evaluations of the NCEP global ensemble in predicting tropical cyclone genesis with a manual tracking method. Results, potential problems, and possible improvement will be presented during the conference.