Tropical cyclone activity in the Atlantic exhibits variability that encompasses seasonal to decadal timescales. Past studies have shown that a key factor that influences Atlantic tropical cyclone activity is the variability of the vertical shear over the main development region (MDR), a large area in the Atlantic within which the majority of tropical cyclones develop. This significant finding points towards the need to better understand the factors that contribute to the variability of the MDR vertical shear in order to improve our knowledge as well as forecast skill of tropical cyclone activity.

In this study, we consider the seasonal to decadal variability of the MDR vertical shear. The objectives include the examination of the spatial and temporal characteristics of the vertical shear variability and their relationship with Atlantic sea surface temperatures, African rainfall and ENSO. This work is in progress and the results to be presented at the conference will emphasize the role of local and teleconnection processes that influence the vertical shear over the MDR.