Thursday, 26 January 2012: 4:15 PM
Extended Prediction of North Indian Ocean Tropical Cyclones Using the ECMWF Variable Ensemble Prediction System
Room 238 (New Orleans Convention Center )
This analysis examines the predictability of several key forecasting parameters using the ECMWF Variable Ensemble Prediction System (VarEPS) for tropical cyclones (TCs) in the North Indian Ocean including: tropical cyclone genesis, pre-genesis and post-genesis track and intensity projections, and regional outlooks of tropical cyclone activity for the Arabian Sea and the Bay of Bengal. Based on the evaluation period from 2007 to 2010, the VarEPS TC genesis forecasts demonstrate low false alarm rates and moderate to high probabilities of detection for lead-times of one to seven days. In addition, VarEPS pre-genesis track forecasts on average perform similar to the VarEPS post-genesis forecasts through 120 hrs and feature a total track error growth of 41 nm per day. The VarEPS provides superior track forecasts for lead-times greater than 12 hrs compared to other models including: UKMET, NOGAPS, and GFS, and slightly lower track errors than the Joint Typhoon Warning Center. Given the societal need for a modern forecasting system that extends beyond three days in the North Indian Ocean, we conclude with a discussion of how the VarEPS can provide much of this extended predictability in a probabilistic framework.
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