Southern hemisphere tropical cyclone intensity forecast methods used at the Joint Typhoon Warning Center, Part II: statistical-dynamical forecasts

Abstract

The development and performance of a statistical - dynamical tropical cyclone intensity forecast model, which was developed for the United States of America’s Joint Typhoon Warning Center (JTWC), is described. This model, called the Southern Hemisphere Statistical Typhoon Intensity Prediction Scheme (SH STIPS), mirrors similar capabilities created for use in the western North Pacific and North Indian Ocean tropical cyclone basins. The model is created by fitting an optimal combination of factors related to climatology and persistence, intensification potential, vertical wind shear, dynamic size/intensity forecasts and atmospheric stability. All of these factors except the climatology and persistence information are derived from global forecast model analyses and forecasts. In July 2005 the SH STIPS model began a real-time evaluation period. The forecasts from the SH STIPS model have outperformed the combined climatology and persistence based forecast and thus are skillful in independent testing since that time. Since October 2006, SH STIPS has been the primary member in an operational consensus forecast of tropical cyclone intensity change provided to the JTWC. Documentation is provided for potential users of forecasts based on this methodology and for researchers interested in developing similar capabilities in the future