Role of African Easterly Waves and embedded vorticity features in genesis of tropical cyclones over the Eastern Tropical Atlantic

It has long been known that African Easterly Waves (AEWs) often serve as precursors for Atlantic tropical cyclones in predominantly the so called Main Development Region (MDR). While it is often assumed that the year-to-year number of AEWs is fairly constant, our work has nevertheless shown that there exists a rich variability in the nature and characteristics of these weather systems on multiple space- and timescales – from decadal and interannual to day-to-day variations.

We are going to use the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA40 dataset for the analysis of individual cases and for a composite analysis for developing/non-developing storm systems. In particular, our investigation focuses on important differences in the horizontal and vertical structure of the precursors over West Africa, and how this affects the further outcome towards cyclogenesis or not.