Organization of deep convection by a low-level circulation in the genesis and intensification of tropical cyclones

Geostationary satellite imagery are used in conjunction with meteorological analyses to document the morphology of deep convection in tropical cyclogenesis events occurring in the 2010 Atlantic hurricane season, and the relation of this convection to the nearby environmental flow. Forecasters regard the circular organization of deep convection by a low-level circulation as a prerequisite for genesis of a tropical depression. Whereas most environmental factors regulating genesis can be quantified by standard meteorological measurements, the organizational criterion is subjective. Objective analysis of high-frequency imagery allows quantitative criteria to be identified retrospectively, not only for the tendency towards circular organization, but for other factors influencing convection and its remnant cloud, such as gravity waves and horizontal/radial advection. A detailed analysis of LISA (2010) in the eastern Atlantic will be presented, illustrating these phenomena together with environmental steering effects and development of the low-level cloud swirl. Comparison will be made to other storms including those sampled by PREDICT and GRIP.