Tropical Cyclone Wind Probability Forecasting (WINDP)

Book excerpt: The development of a model to estimate 30 and 50 kt wind probabilities from tropical cyclone forecasts is described. Some examples to illustrate the use of probabilities are discussed. The model is based on position forecast errors, which are used to determine the probability of a cyclone occupying a particular geographical position, and on wind profile errors. Wind profile errors consist of errors in the forecast maximum wind and errors in the forecast radius of 30 and 50 kt winds. The profile errors are used to estimate the probability of 30 an 50 kt winds occurring at a point, given that the cyclone occupies a particular position. These position and wind probability elements are combined by using an assumption of independence which is supported by correlation coefficients. The model, which includes features of the earlier strike probability model, is tested on independent data. Test results are shown to illustrate good agreement between forecast probability and the frequency of occurrence of 30 and 50 kt winds. (Author).