Updated environmental structure characteristics for southern hemisphere application of the Systematic Approach to Tropical Cyclone Track Forecasting

Bannister et al. (1997, 1998) have previously developed a Meteorological Knowledge base for all Southern Hemisphere tropical cyclones (TC) during the 1990-91 through 1997-98 seasons. They found all TC scenarios could be classified with only a small set of conceptual models. The basic Systematic Approach concepts of associating characteristic TC tracks with specific environment circulations, and identifying TC structure characteristics that may lead to an environment structure change, have been demonstrated to be valid. An explanation for all significant track changes has been possible in terms of only a small set of transitional mechanisms.

This data base has been extended by adding the 1998-99 season. More importantly, the synoptic patterns and regions have been re-defined to be compatible with a set of conceptual models that is intended to have global applicability. A new "climatology" of synoptic patterns and regions has been prepared. Characteristic track segments associated with each synoptic pattern/region combination have been re-done. Some new conceptual models have been introduced that describe the environment structure changes leading to track changes. New summaries of all recurring (more than three occurrences) transitions have been prepared.