A Cape Verde hurricane or Cabo Verde hurricane is an Atlantic hurricane that originates at low-latitude in the tropical Atlantic from a tropical wave that has passed over or near the Cape Verde islands after exiting the coast of West Africa. The average Atlantic 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, and some, such as hurricanes Allen, Ivan, Dean, and Irma have set various 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 and their movement through the Main Development Region.
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. [1] 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 cyclones soon after moving off the coast, [2] within 10 to 15 degrees latitude, or 1,100 kilometres (680 mi) to 1,600 kilometres (990 mi), of the Cape Verde Islands; [1] this comprises the tropical latitudes east of the 40th meridian west.
Twenty nations took part in the GATE research project in 1974, where Douglas DC-6 aircraft examined tropical waves which spawned Cape Verde hurricanes. [3] In 2006, there was a two-month research project known as NAMMA-06 (short for NASA African Monsoon Multidisciplinary Activities) [4] which flew Douglas DC-8s into seedling disturbances in the eastern Atlantic which had the potential to become Cape Verde hurricanes. [5] [6]
The 2003 Atlantic hurricane season was a very active season with tropical cyclogenesis occurring before and after the official bounds of the season—the first such occurrence since the 1970 season. The season produced 21 tropical cyclones, of which 16 developed into named storms; seven of those attained hurricane status, of which three reached major hurricane status. The strongest hurricane of the season was Hurricane Isabel, which reached Category 5 status on the Saffir–Simpson hurricane scale northeast of the Lesser Antilles; Isabel later struck North Carolina as a Category 2 hurricane, causing $3.6 billion in damage and a total of 51 deaths across the Mid-Atlantic region of the United States.
The 2001 Atlantic hurricane season was a fairly active Atlantic hurricane season that produced 17 tropical cyclones, 15 named storms, nine hurricanes, and four major hurricanes. The season officially lasted from June 1, 2001, to November 30, 2001, dates which by convention limit the period of each year when tropical cyclones tend to form in the Atlantic Ocean basin. The season began with Tropical Storm Allison on June 4, and ended with Hurricane Olga, which dissipated on December 6.
The 1978 Atlantic hurricane season was a slightly above average hurricane season in terms of number of named storms. Eleven tropical cyclones were named in all, and five of these became hurricanes; two of the five became a major hurricane. This was also the last Atlantic hurricane season to use an all-female naming list. The season officially began on June 1, 1978, and ended on November 30, 1978. These dates, adopted by convention, denote the period in each year when most tropical cyclogenesis occurs in the Atlantic basin. However, the formation of subtropical or tropical cyclones is possible at any time of the year, as shown by the formation of an unnamed subtropical storm on January 18.
The 1982 Atlantic hurricane season was an extremely inactive Atlantic hurricane season with five named tropical storms and one subtropical storm. Two storms became hurricanes, one of which reached major hurricane status. The season officially began on June 1, 1982, and lasted until November 30, 1982. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. Activity started early with Hurricane Alberto forming on the first day of the season. Alberto threatened the Southwestern Florida coast as a tropical storm, meadering offshore in the southeastern Gulf of Mexico and causing 23 fatalities in Cuba. The next system, a subtropical storm, formed later in June and affected the same area as Alberto, causing $10 million in damage.
The 1983 Atlantic hurricane season was the least active Atlantic hurricane season since 1930. The season officially began on June 1, 1983, and lasted until November 30, 1983. These dates conventionally delimit the period of each year when most storms form in the Atlantic basin. The season had very little activity, with only seven tropical depressions, four of which reached tropical storm strength or higher. This led to the lowest accumulated cyclone energy count since 1977.
The 1984 Atlantic hurricane season was the most active since 1971, though the season was below average in hurricanes and major hurricanes. It officially began on June 1, 1984, and lasted until November 30, 1984. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. The 1984 season was an active one in terms of named storms, but most of them were weak and stayed at sea. Most of the cyclones tracked through the northwest subtropical Atlantic west of the 50th meridian to near the Eastern coast of the United States between mid-August and early October. The most damaging storm was Hurricane Klaus, which caused $152 million (1984 dollars) in damage in Puerto Rico. Hurricane Diana was the first hurricane to strike a nuclear power plant without incident; it was also the first major hurricane to strike the U.S. East Coast in nearly 20 years. Also of note was Hurricane Lili, which lasted well after the official end of the season. It was downgraded from a named storm on December 24. Damage overall from the tropical cyclones in 1984 totaled $228.7 million. Unusually, no hurricanes developed from tropical waves in 1984, which usually are the source of the strongest storms in an Atlantic hurricane season.
The 1988 Atlantic hurricane season was a near average season that proved costly and deadly, with 15 tropical cyclones directly affecting land. The season officially began on June 1, 1988, and lasted until November 30, 1988, although activity began on May 30 when a tropical depression developed in the Caribbean. The June through November dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. The first cyclone to attain tropical storm status was Alberto on August 8, nearly a month later than usual. The final storm of the year, Tropical Storm Keith, became extratropical on November 24. The season produced 19 tropical depressions of which 12 attained tropical storm status. One tropical storm was operationally classified as a tropical depression but was reclassified in post-analysis. Five tropical cyclones reached hurricane status of which three became major hurricanes reaching Category 3 on the Saffir–Simpson scale. But until 34 years later in 2022 Atlantic hurricane season, had Pacific-Atlantic hurricane crossover.
The 1989 Atlantic hurricane season was an average hurricane season with 11 named storms. The season officially began on June 1, and ended on November 30. The first tropical cyclone, Tropical Depression One, developed on June 15, and dissipated two days later without any effects on land. Later that month, Tropical Storm Allison caused severe flooding, especially in Texas and Louisiana. Tropical Storm Barry, Tropical Depressions Six, Nine, and Thirteen, and Hurricanes Erin and Felix caused negligible impact. Hurricane Gabrielle and Tropical Storm Iris caused light effects on land, with the former resulting in nine fatalities from rip currents offshore the East Coast of the United States and Atlantic Canada, while the latter produced minor flooding in the United States Virgin Islands.
The 1990 Atlantic hurricane season was the most active Atlantic hurricane season since 1969, with a total of 14 named storms. The season also featured eight hurricanes, one of which intensified into a major hurricane. It officially began on June 1, 1990, and lasted until November 30, 1990. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. However, tropical cyclogenesis can occur prior to the start of the season, as demonstrated with Tropical Depression One, which formed in the Caribbean Sea on May 24.
The 1991 Atlantic hurricane season was the first season since 1984 in which no hurricanes developed from tropical waves, which are the source for most North Atlantic tropical cyclones. The hurricane season officially began on June 1, and ended on November 30. It was the least active in four years due to higher than usual wind shear across the Atlantic Ocean. The first storm, Ana, developed on July 2 off the southeast United States and dissipated without causing significant effects. Two other tropical storms in the season – Danny and Erika – did not significantly affect land. Danny dissipated east of the Lesser Antilles, and Erika passed through the Azores before becoming extratropical. In addition, there were four non-developing tropical depressions. The second depression of the season struck Mexico with significant accompanying rains.
A tropical wave, in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which moves from east to west across the tropics, causing areas of cloudiness and thunderstorms. Tropical waves form in the easterly flow along the equatorial side of the subtropical ridge or belt of high air pressure which lies north and south of the Intertropical Convergence Zone (ITCZ). Tropical waves are generally carried westward by the prevailing easterly winds along the tropics and subtropics near the equator. They can lead to the formation of tropical cyclones in the north Atlantic and northeastern Pacific basins. A tropical wave study is aided by Hovmöller diagrams, a graph of meteorological data.
The 2006 Atlantic hurricane season was the least active in the basin since 1997, with nine named storms as well as an additional unnamed tropical storm identified by the National Hurricane Center. 2006 was the first season since 2001 in which no hurricanes made landfall in the United States, and was the first since 1994 in which no tropical cyclones formed during October. Following the intense activity of 2003, 2004, and 2005, forecasters predicted that the 2006 season would be only slightly less active. Instead, it turned out to be a below average season, as activity was slowed by a rapidly forming moderate El Niño event, the presence of the Saharan Air Layer over the tropical Atlantic, and the steady presence of a robust secondary high-pressure area to the Azores High centered on Bermuda. There were no tropical cyclones after October 2.
An Atlantic hurricane is a type of tropical cyclone that forms in the Atlantic Ocean primarily between June and November. The terms "hurricane", "typhoon", and "cyclone" can be used interchangeably to describe this weather phenomenon. These storms are continuously rotating around a low pressure center, which causes stormy weather across a large area, which is not limited to just the eye of the storm. Organized systems of clouds and thunderstorms that originate over tropical or subtropical waters and have closed low-level circulation, and is not to be confused with tornadoes, which are just another type of cyclone. They form over low pressure systems. In the North Atlantic and the Eastern Pacific, the term "hurricane" is used, whereas "typhoon" is used in the Western Pacific near Asia. The more general term "cyclone" is used in the rest of the ocean basins, namely the South Pacific and Indian Ocean.
Hurricane Irene was a long-lived Cape Verde hurricane during the 2005 Atlantic hurricane season. The storm formed near Cape Verde on August 4 and crossed the Atlantic, turning northward around Bermuda before being absorbed by an extratropical cyclone while situated southeast of Newfoundland. Irene proved to be a difficult storm to forecast due to oscillations in strength. After almost dissipating on August 10, Irene peaked as a Category 2 hurricane on August 16. Irene persisted for 14 days as a tropical system, the longest duration of any storm of the 2005 season. It was the ninth named storm and fourth hurricane of the record-breaking season.
Hurricane Gladys was the farthest tropical cyclone from the United States to be observed by radar in the Atlantic basin since Hurricane Carla in 1961. The seventh named storm and fifth hurricane of the 1975 Atlantic hurricane season, Gladys developed from a tropical wave while several hundred miles southwest of Cape Verde on September 22. Initially, the tropical depression failed to strengthen significantly, but due to warm sea surface temperatures and low wind shear, it became Tropical Storm Gladys by September 24. Despite entering a more unfavorable environment several hundred miles east of the northern Leeward Islands, Gladys became a Category 1 hurricane on the Saffir–Simpson hurricane wind scale on September 28. Shortly thereafter, the storm reentered an area favorable for strengthening. Eventually, a well-defined eye became visible on satellite imagery.
Traditionally, areas of tropical cyclone formation are divided into seven basins. These include the north Atlantic Ocean, the eastern and western parts of the northern Pacific Ocean, the southwestern Pacific, the southwestern and southeastern Indian Oceans, and the northern Indian Ocean. The western Pacific is the most active and the north Indian the least active. An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones, super typhoons, or major hurricanes.
The 1924 Atlantic hurricane season featured the first officially recorded Category 5 hurricane, a tropical cyclone with maximum sustained winds exceeding 155 mph (249 km/h) on the modern-day Saffir–Simpson scale. The first system, Tropical Storm One, was first detected in the northwestern Caribbean Sea on June 18. The final system, an unnumbered tropical depression, dissipated on November 24. These dates fall within the period with the most tropical cyclone activity in the Atlantic. Of the 13 tropical cyclones of the season, six existed simultaneously. The season was average with 11 tropical storms, five of which strengthened into hurricanes. Further, two of those five intensified into major hurricanes, which are Category 3 or higher on the Saffir–Simpson scale.
The 2009 Atlantic hurricane season was a near-average Atlantic hurricane season that produced eleven tropical cyclones, nine named storms, three hurricanes, and two major hurricanes. It officially began on June 1 and ended on November 30, dates that conventionally delimit the period of each year when most tropical cyclones develop in the Atlantic basin. The season's first tropical cyclone, Tropical Depression One, developed on May 28, while the final storm, Hurricane Ida, dissipated on November 10. The most intense hurricane, Bill, was a powerful Cape Verde-type hurricane that affected areas from the Leeward Islands to Newfoundland. The season featured the lowest number of tropical cyclones since the 1997 season, and only one system, Claudette, made landfall in the United States. Forming from the interaction of a tropical wave and an upper-level low, Claudette made landfall on the Florida Panhandle with maximum sustained winds of 45 mph (70 km/h) before quickly dissipating over Alabama. The storm killed two people and caused $228,000 in damage.
The 2012 Atlantic hurricane season was the final year in a string of three consecutive very active seasons since 2010, with 19 tropical storms. The 2012 season was also a costly one in terms of property damage, mostly due to Hurricane Sandy. The season officially began on June 1 and ended on November 30, dates that conventionally delimit the period during each year in which most tropical cyclones form in the Atlantic Ocean. However, Alberto, the first named system of the year, developed on May 19 – the earliest date of formation since Subtropical Storm Andrea in 2007. A second tropical cyclone, Beryl, developed later that month. This was the first occurrence of two pre-season named storms in the Atlantic basin since 1951. It moved ashore in North Florida on May 29 with winds of 65 mph (105 km/h), making it the strongest pre-season storm to make landfall in the Atlantic basin. This season marked the first time since 2009 where no tropical cyclones formed in July. Another record was set by Hurricane Nadine later in the season; the system became the fourth-longest-lived tropical cyclone ever recorded in the Atlantic, with a total duration of 22.25 days. The final storm to form, Tony, dissipated on October 25 – however, Hurricane Sandy, which formed before Tony, became extratropical on October 29.