North Western Pacific Tropical Cyclone Ensemble Forecast Project

Abstract

ABSTRACT: The WMO/TCP and WWRP launched the North Western Pacific Tropical Cyclone Ensemble Forecast Project (NWP-TCEFP) in 2009 to explore the utility of ensemble forecasts, including multi-model ensemble forecasts of TCs, and to promote such products for operational TC forecasting. Operational global medium-range ensembles, which have been exchanged in real-time in a CXML format under the initiative of the WMO GIFS-TIGGE Working Group, have been used to create ensemble products of TC tracks that were used by the Typhoon Committee Members and forecasters participating in the SWFDP in Southeast Asia through a password-protected website developed and maintained by the JMA.In some cases many or all of the ensembles have simultaneously predicted small or large ensemble spreads in TC tracks. The implication is that multi-model ensemble products provide forecasters with additional information on forecast certainty or uncertainty and thus increase the level of confidence in the forecasts. Another important outcome of the project was the responses to surveys conducted by the WMO/TCP and WWRP and also by the WMO GIFS-TIGGE Working Group. The responses confirmed that ESCAP/WMO Typhoon Committee Members have routinely accessed the website and have recognized the usefulness of the ensemble products available on the website for operational TC forecasting. Keywords: tropical cyclone, ensemble forecasting, THORPEX, TIGGE