Climatological analysis of tropical cyclogenesis in the North Atlantic and Eastern North Pacific basins

As a first step in the development of methods for prediction of tropical cyclogenesis, the climatology of storm formation in the North Atlantic and Eastern North Pacific basins is examined.

The North Atlantic basin was divided into five sub-regions based on observed clusters of tropical cyclogenesis. Within each of the five sub-regions, and the Eastern North Pacific basin, historical data from the HURDAT data base collected during years in which there was operational satellite data (1966-1998) was analyzed as to the incidence of genesis. Results show that there is considerable variation in the peaks of the frequency distributions in the sub-regions.

Tropical cyclogenesis within the North Atlantic and Eastern North Pacific basins, and the North Atlantic sub-regions was also analyzed for years relative to El Nino/La Nina. It was found that suppression of cyclogenesis in the North Atlantic during El Nino years is most evident in the tropical North Atlantic sub-region as cyclogenesis is actually enhanced in the Gulf of Mexico during these years. For La Nina years, enhanced cyclogenesis is most evident in the northern and tropical regions of the North Atlantic. In the Eastern North Pacific, the years before El Nino are the most active.