Cyclogue - analogic prediction of the course of tropical cyclones by National Meteorological Analysis Centre, Melbourne.

Reprint

A second computer-based objective aid to predict tropical cyclone course was introduced in 1976 at National Meteorological Centre, Melbourne, where it is available as an on call service for Australia's Tropical Cyclone Warning Centres. The paper describes how the new aid identifies similar storms from the past history of Australian region tropical cyclones, sorts them into an order of preference and appends a simplistic prediction scheme for a cyclone's path. A plotted map display of a forecast is available in which ellipses of equi-probable position are featured. Characteristics of the retrieval and prediction schemes and of the output are discussed and the accuracy of the method indicated. The program closely resembles analogic forecast techniques introduced by other forecasting agencies servicing the tropics. However the score ranking system is new, as is the method of varying the size of the search envelope to ensure that the program provides a result almost every time