During the 1959 season for tropical storms in the Northern Hemisphere, Joint Numerical Weather Prediction (JNWP) Unit computed operationally one or more forecast tracks for 11 hurricanes and tropical storms and 11 typhoons. The 500-mb barotropic forecast flow with the tropical vortex eliminated from the initial 500-mb analysis was employed as the steering current in obtaining these forecasts. A summary of 1959 forecasts and a table of verification of JNWP hurricane forecasts for the years 1956 through 1959 are presented. The improvement and deterioration in forecasts from one year to the next are discussed in terms of sample size, operational changes, and analysis and forecasting techniques specifically designed for forecasting trajectories of tropical cyclones.
