Lawrence Berkeley National Laboratory

African easterly waves (AEWs) are known precursors to Atlantic tropical cyclones (TCs), and are therefore often directly connected to extreme weather events that can be both deadly and destructive. It is well established that not all AEWs develop into TCs, and there has been substantial research that has addressed the different characteristics and environments of developing and non-developing waves. In this study, however, we specifically examine 41-years of developing AEWs to provide a better understanding of the relationship between the developing wave and the environment, and the resulting TC. To conduct this research, we identified TCs with AEW origins from the observational record between 1980 and 2020. We then used an objective tracking algorithm to identify the developing AEWs in reanalysis data. We found a statistically significant relationship between the strength of the developing AEWs, TC genesis location and landfall, and sea surface temperature (SST) during TC genesis. Weaker AEWs tend to develop into TCs closer to the Americas in a region with warmer SSTs than those of the stronger AEWs, which tend to develop into TCs closer to Africa. Consequently, the TCs that develop from weaker AEWs are more likely to make landfall due to the close proximity of their genesis locations to the Americas.