On the Predictability of Tropical Cyclone Tracks in the Northwest Pacific Basin

A new Northwest Pacific climatology and persistence (CLIPER) model is derived with historical tropical cyclone tracks during the satellite and aircraft reconnaissance era (1970–95). The new CLIPER extends the forecasts from 3 to 5 days and exhibits smaller forecast biases than the previous CLIPER, although forecast errors are comparable. The new model is based on more accurate historical tropical cyclone track data, and a simpler derivation of the regression equations, than is the old model. Nonlinear systems analysis shows that the predictability timescale in which the average errors increase by a factor e is just over 15 h, which is about the same as that calculated by similar methods near Australia and in the North Atlantic. This suggests that 5-day tropical cyclone track forecasts may be beneficial, assuming small initial errors; therefore, a CLIPER model extended to 5 days is needed as a baseline to measure the forecast skill.