Impact of New Global Models and Ensemble Prediction Systems on Consensus TC Track Forecasts

James S. Goerss


The interpolated versions of seven high-quality TC track forecast models are routinely available to the forecasters at NHC. The seven models are: GFS, GFDL, and the Hurricane WRF (AVNI, GFDI, and HWFI; NCEP); NOGAPS and GFDN (NGPI and GFNI; FNMOC); the UKMO global model (EGRI); and the ECMWF global model (EMXI). The operational consensus forecast aid, TVCN, is formed by giving equal weight to the available forecasts from AVNI, GFDI, HWFI, NGPI, GFNI, EGRI, and EMXI. Prior to the start of the 2009 season, upgrades were made to the Canadian global model (CMC). During the course of the season it was found that the TC track forecasts in the Atlantic for CMC were much improved over previous seasons. As part of the Hurricane Forecast Improvement Project Demonstration, a number of ensembles were run using different configurations of the NOAA/ESRL FIM (a global model using a flow-following vertical coordinate, finite-volume numerics, and an icosahedral global grid). Interpolated versions of these new models and their ensemble means were computed for the Atlantic and eastern North Pacific for the 2009 season. The TC track forecast performance of these models and ensemble means are compared with that for the TVCN models. Finally, a number of experimental consensus forecast aids are formed combining these models and ensemble means with the TVCN models and their TC track forecast performance is compared with that for TVCN.