A model of the tangential wind speed in the outer regions of tropical cyclones is proposed based on approximate conservation of angular momentum. The purpose is to derive an operationally useful model of the beta-effect propagation (BEP), which barotropic numerical models have shown to be primarily related to the outer wind structure. The functional dependence of the predicted BEP speeds over a range of latitudes and the radii Ro at which the cyclonic winds are reduced to zero is determined from dimensional analysis. Given the empirical nature of the profile and imprecise estimates of Ro, only four tropical cyclone sizes or outer wind structures are defined based on the magnitude of the BEP speeds and their relative contributions to the total motion. A second aspect of BEP from the barotropic model integrations is the development of a trailing anticyclone to the southeast of the tropical cyclone as a result of Rossby wave dispersion. The four tropical cyclone size categories or outer wind structu... Abstract A model of the tangential wind speed in the outer regions of tropical cyclones is proposed based on approximate conservation of angular momentum. The purpose is to derive an operationally useful model of the beta-effect propagation (BEP), which barotropic numerical models have shown to be primarily related to the outer wind structure. The functional dependence of the predicted BEP speeds over a range of latitudes and the radii Ro at which the cyclonic winds are reduced to zero is determined from dimensional analysis. Given the empirical nature of the profile and imprecise estimates of Ro, only four tropical cyclone sizes or outer wind structures are defined based on the magnitude of the BEP speeds and their relative contributions to the total motion. A second aspect of BEP from the barotropic model integrations is the development of a trailing anticyclone to the southeast of the tropical cyclone as a result of Rossby wave dispersion. The four tropical cyclone size categories or outer wind structu...