Analysis of National Hurricane Center track forecast errors based upon geographic location

Considering all Atlantic tropical storms and hurricanes, the National Hurricane Center mean absolute track forecast error (NHC MAE) has systematically decreased since the 1970s. However, tropical cyclones in the Atlantic Basin experience a large amount of variability in terms their formation and propagation characteristics. In fact, a significant proportion of the variability in track forecast errors in the Atlantic Basin may be attributed to differences between three geographic regions: the main development, baroclinic, and Gulf/Caribbean region. This study seeks to understand how the decrease in NHC MAE, from 1970-1997 to 1998-2007, varies between three geographic regions in the Atlantic Basin. Defining improvement as the decrease in NHC MAE from 1970-1997 to 1998-2007, each of the three geographic regions experience a statistically significant improvement at the 12, 24, 48, and 72 hour forecasts. However, the largest and most significant improvements occur within the baroclinic region. At all forecast periods, the improvement in NHC MAE is significantly larger in the baroclinic region than in the main development region. Additionally, this study qualitatively analyzes the bivariate distribution of the along- and cross-track error components in each region through the use of Gaussian kernel densities and mean biases. While the main development and baroclinic region had a negative along-track bias from 1970-1997 that is largely eliminated by the 1998-2007 period, the Gulf/Caribbean region had no systematic along- or cross-track over the entire 37 year period.