Australian East-Coast Cyclones. Part II: Numerical Modeling Study

Abstract

A series of numerical modeling simulations are made of the type 2 east-coast cyclone described in Holland et al. The aims are (i) to show that this mesoscale development can be successfully forecast from initial synoptic scale data and (ii) to diagnose the relative roles of large-scale processes, convection, topography, and surface fluxes in producing this development. We show that the development can be forecast successfully with the current Australian limited-area prediction model, but that high resolution is needed to capture fully the intensity, structure and track of the system. We show also that both large- and small-scale processes contribute to the development of the east-coast cyclone. Large-scale moist baroclinic processes provide the favorable environment and initial development of a weak, synoptic-scale cyclone. Subsequent development of the intense, mesoscale system requires convective release of latent heat, local orographic forcing, and high resolution surface energy fluxes.