Abstract
Western North Pacific tropical cyclone position forecast errors for 10 years (1966–75) are statistically analyzed. Variations of errors versus a number of parameters are examined. It is shown that a small number of readily available parameters, such as location, maximum wind and components of motion, can, with reasonable effectiveness, classify a tropical cyclone forecast as representing a group with either markedly above or below average errors. The annual variations of forecast errors are also discussed and an attempt is made to explain those variations.