The structure and the dynamics of the convective systems over West Africa and the eastern Atlantic, which were embedded in an African Easterly wave out of which Hurricane Helene developed in September 2006, are investigated. The tropical cyclogenesis of Helene was accompanied by several marked dust outbreaks. Thus, the second part of this study investigates the transport of mineral dust and the impact of the dust-radiation feedback for this African easterly wave. The study is based on both COSMO (COnsortium for Small scale Modelling) and COSMO-ART (Aerosols and Reactive Trace gases) model runs. In COSMO-ART the dust emission and dust transport as well as the radiation feedback are taken into account.