Cape Verde-type hurricane

A Cape Verde hurricane is an Atlantic hurricane that originates at low-latitude in the deep tropics, titularly from a tropical wave that has passed over or near the Cape Verde islands after exiting the coast of West Africa. The average hurricane season has about two Cape Verde hurricanes, which are often the largest and most intense storms of the season due to having plenty of warm open ocean over which to develop before encountering land or other factors prompting weakening. A good portion of Cape Verde storms are large, some setting records. Most of the longest-lived tropical cyclones in the Atlantic basin are Cape Verde hurricanes. While many move harmlessly out to sea, some move across the Caribbean sea and into the Gulf of Mexico, becoming damaging storms for Caribbean nations, Central America, Mexico, Bermuda, the United States, and occasionally even Canada. Research projects since the 1970s have been launched to understand the formation of these storms.

Prior to the early 1940s, the term Cape Verde hurricane referred to August and early September storms that formed to the east of the surface plotting charts in use at the time. Cape Verde hurricanes typically develop from tropical waves which form in the African savanna during the wet season, then move into the African steppes. The disturbances move off the western coast of Africa and become tropical storms or tropical cyclones soon after moving off the coast, within 10 to 15 degrees longitude, or 10,760 kilometres (6,690 mi) to 16,140 kilometres (10,030 mi), of the Cape Verde Islands; this comprises the tropical latitudes east of the 40th meridian west. In the years since the phrase's coining, increasing detection has allowed meteorologists to determine that Cape Verde hurricanes have formed as early as July 4 (Hurricane Bertha of 1996) or as late as September 26 (Hurricane Flora).

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