Impacts of the large-scale circulation on the formation of Cape Verde storms

Cape Verde storms in the Atlantic basin are tropical cyclones that develop off the west coast of Africa near the Cape Verde islands. These storms are more likely to develop into major hurricanes because they spend a longer time period over warm oceans prior to making a landfall or recurving northeastward. Cape Verde storms generally form in July-September. An average year sees about two Cape Verde storms. The climate and weather conditions over West Africa and the East Atlantic are examined in this study to better understand the large-scale factors favorable for the formation of Cape Verde storms. Besides the impact of the Madden-Julian oscillation (MJO) and the El Nino-Southern oscillation (ENSO), the structure of the African easterly jet, the African easterly wave activity and structure, and the variability of the West African monsoon will also be examined.