Performance of the ECMWF High-Resolution Global Model and its Impact on Consensus during the 2006 Northern Hemisphere Season
Michael Fiorino Michael.Fiorino@noaa.gov
Techniques Development and Applications Unit National Hurricane Center Miami, FL
The European Centre for Medium-range Weather Forecasts (ECMWF) has diagnosed tropical cyclones (TCs) in their Ensemble Prediction System (EPS) since 2003 and distributes their TC tracker output via the GTS in the BUFR format. In 2006, NHC began processing these BUFR trackers and found significant differences in the model intensity forecasts compared to TC trackers run in the USA against coarser-resolution ECMWF fields (Δx = 1.0°); presumably because the ECMWF trackers operate directly on the model grids for: 1) the “deterministic” run (Tl 799L91, Δx ~ 0.25°); and 2) the 51 members of EPS run (Tl399L62, Δx ~ 0.50°).
This difference motivated a more thorough analysis of ECMWF model performance that goes beyond medium-range TC track prediction and the results suggest that high- resolution models are on the verge of making skillful intensity forecasts. The challenge, however, is to remove model bias and the development of new techniques to form multi- model consensus specifically for the intensity problem.
This brief will review both the intensity and medium-long range track prediction skill of the ECMWF model for all northern Hemisphere basins during the 2006 season and will highlight the model’s positive contribution to consensus.