Extended Abstract (20K)5C.1
Estimation of Tropical Cyclone Track Forecast Uncertainty
James S. Goerss, NRL, Monterey, CA
Consensus tropical cyclone (TC) track forecast aids formed using TC track forecasts from regional and global numerical weather prediction models have become increasingly important in recent years as guidance to TC forecasters at both the National Hurricane Center (NHC) and the Joint Typhoon Warning Center. Forecasters at NHC routinely utilize consensus forecast aids (GUNS and GUNA) formed using the interpolated TC track forecasts from the GFDL model and the Global Forecast System run at NCEP, the Navy Operational Global Atmospheric Prediction System, and the UK Meteorological Office global model. In this study a third consensus aid (CONU) is formed using the interpolated TC track forecasts from the GFDL model run at FNMOC along with those from the aforementioned models. The TC track forecast performance out to five days for these models and the various consensus aids derived utilizing these models is evaluated for the 2000-2003 Atlantic hurricane seasons. In particular, the uncertainty in the TC track forecasts, as measured by the standard deviation and 95th percentile of forecast position error, is determined for GUNS, GUNA, and CONU. The relationships between forecast uncertainty and (1) consensus spread, (2) the number of models available to the consensus, (3) TC intensity, (4) TC motion, and (5) TC location are examined so that forecasters might assign a priori some level of confidence to their TC track forecasts based on the available guidance.
Session 5C, Tropical Cyclone Prediction and Predictability I: Track
Tuesday, 4 May 2004, 8:00 AM-9:30 AM, Napoleon II Room
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