Relationship between Tropical Cyclone Genesis in the Main Development Region and Seasonal Tropical Cyclone Activity in the Atlantic Basin

Seasonal tropical cyclone (TC) activity in the Atlantic basin has been linked to many factors, ranging from global phenomena such as the El Nino Southern Oscillation to local features such as the Atlantic subtropical high. TC genesis is an important factor in seasonal TC activity that requires more research and may have implications for basin-wide TC activity. In this study, TC genesis in the main development region was evaluated from 1972-2015 to determine its relationship with seasonal TC activity. In particular, a strong correlation was found between the number of TCs that developed east of 42°W and overall TC activity for the entire Atlantic basin. In years when three or fewer TCs developed east of 42°W (3EY), an average of nine TCs were named in the entire basin. On the other hand, in years when four or more TCs developed east of 42°W (4EY), an average of 16 TCs were named basin-wide. Further, accumulated cyclone energy (ACE) in 4EYs was more than double the ACE in 3EYs. Analysis showed that 4EYs uncharacteristically generated more TCs in August than in September and yielded more TCs in July than climatology. This research strongly suggests that TC genesis east of 42°W is positively correlated with basin-wide TC activity. Future research will focus on the evaluation of the eastern main development region (e.g., moisture, vertical wind shear, instability) to investigate the annual variability of TC genesis in this region and its potential connection to the rest of the Atlantic basin.