An Atlantic hurricane or tropical storm is a tropical cyclone that forms in the Atlantic Ocean, usually between the months of June and November. A hurricane differs from a cyclone or typhoon only on the basis of location. A hurricane is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a cyclone occurs in the south Pacific or Indian Ocean.
Tropical cyclones can be categorized by intensity. Tropical storms have one-minute maximum sustained winds of at least 39 mph (34 knots, 17 m/s, 63 km/h), while hurricanes have one-minute maximum sustained winds exceeding 74 mph (64 knots, 33 m/s, 119 km/h). Most North Atlantic tropical storms and hurricanes form between June 1 and November 30. The United States National Hurricane Center monitors the basin and issues reports, watches, and warnings about tropical weather systems for the North Atlantic Basin as one of the Regional Specialized Meteorological Centers for tropical cyclones, as defined by the World Meteorological Organization.
In recent times, tropical disturbances that reach tropical storm intensity are named from a predetermined list. Hurricanes that result in significant damage or casualties may have their names retired from the list at the request of the affected nations in order to prevent confusion should a subsequent storm be given the same name. On average, in the North Atlantic basin (from 1966 to 2009) 11.3 named storms occur each season, with an average of 6.2 becoming hurricanes and 2.3 becoming major hurricanes (Category 3 or greater). The climatological peak of activity is around September 10 each season.
In March 2004, Catarina was the first hurricane-intensity tropical cyclone ever recorded in the Southern Atlantic Ocean. Since 2011, the Brazilian Navy Hydrographic Center has started to use the same scale of the North Atlantic Ocean for tropical cyclones in the South Atlantic Ocean and assign names to those which reach 35 kn (65 km/h; 40 mph).
Tropical cyclones are steered by the surrounding flow throughout the depth of the troposphere (the atmosphere from the surface to about eight miles (12 km) high). Neil Frank, former director of the United States National Hurricane Center, used the analogies such as "a leaf carried along in a stream" or a "brick moving through a river of air" to describe the way atmospheric flow affects the path of a hurricane across the ocean. Specifically, air flow around high pressure systems and toward low pressure areas influences hurricane tracks.
In the tropical latitudes, tropical storms and hurricanes generally move westward with a slight tendency toward the north, under the influence of the subtropical ridge, a high pressure system that usually extends east-west across the subtropics. South of the subtropical ridge, surface easterly winds (blowing from east to west) prevail. If the subtropical ridge is weakened by an upper trough, a tropical cyclone may turn poleward and then recurve, or curve back toward the northeast into the main belt of the Westerlies. Poleward (north) of the subtropical ridge, westerly winds prevail and generally steer tropical cyclones that reach northern latitudes toward the east. The westerlies also steer extratropical cyclones with their cold and warm fronts from west to east.
|Most intense Atlantic hurricanes|
Generally speaking, the intensity of a tropical cyclone is determined by either the storm's maximum sustained winds or lowest barometric pressure. The following table lists the most intense Atlantic hurricanes in terms of their lowest barometric pressure. In terms of wind speed, Hurricane Allen (in 1980) was the strongest Atlantic tropical cyclone on record, with maximum sustained winds of 190 mph (310 km/h). However, these measurements are suspect since instrumentation used to document wind speeds at the time would likely succumb to winds of such intensity. Nonetheless, their central pressures are low enough to rank them among the strongest recorded Atlantic hurricanes.
Owing to their intensity, the strongest Atlantic hurricanes have all attained Category 5 classification. Hurricane Opal, the strongest Category 4 hurricane recorded, intensified to reach a minimum pressure of 916 mbar (hPa; 27.05 inHg), a pressure typical of Category 5 hurricanes. Nonetheless, the pressure remains too high to list Opal as one of the ten strongest Atlantic tropical cyclones. Presently, Hurricane Wilma is the strongest Atlantic hurricane ever recorded, after reaching an intensity of 882 mbar (hPa; 26.05 inHg) in October 2005; this also made Wilma the strongest tropical cyclone worldwide outside of the West Pacific, where seven tropical cyclones have been recorded to intensify to lower pressures. However, this was later superseded by Hurricane Patricia in 2015 in the east Pacific, which had a pressure reading of 872 mbar. Preceding Wilma is Hurricane Gilbert, which had also held the record for most intense Atlantic hurricane for 17 years. The 1935 Labor Day hurricane, with a pressure of 892 mbar (hPa; 26.34 inHg), is the third strongest Atlantic hurricane and the strongest documented tropical cyclone prior to 1950. Since the measurements taken during Wilma and Gilbert were documented using dropsonde, this pressure remains the lowest measured over land.
Hurricane Rita is the fourth strongest Atlantic hurricane in terms of barometric pressure and one of three tropical cyclones from 2005 on the list, with the others being Wilma and Katrina at first and sixth, respectively. However, with a barometric pressure of 895 mbar (hPa; 26.43 inHg), Rita is the strongest tropical cyclone ever recorded in the Gulf of Mexico. Hurricanes Camille, Mitch, and Dean share intensities for the seventh strongest Atlantic hurricane at 905 mbar (hPa; 26.73 inHg). The tenth place for most intense Atlantic tropical cyclone is Hurricane Maria listed to have deepened to a pressure as low as 908 mbar (hPa; 26.81 inHg).
Many of the strongest recorded tropical cyclones weakened prior to their eventual landfall or demise. However, three of the storms remained intense enough at landfall to be considered some of the strongest landfalling hurricanes – three of the eleven hurricanes on the list constitute the three most intense Atlantic landfalls in recorded history. The 1935 Labor Day hurricane made landfall at peak intensity, making it the most intense Atlantic landfall. Though it weakened slightly before its eventual landfall on the Yucatán Peninsula, Hurricane Gilbert maintained a pressure of 900 mbar (hPa; 26.58 inHg) at landfall, making its landfall the second strongest. Similarly, Hurricane Dean made landfall on the peninsula, though it did so at peak intensity and with a higher barometric pressure; its landfall marked the third strongest in Atlantic hurricane history.
|Total and Average Number of |
Tropical Storms by Month (1851–2017)
|Month||Total||Average per year|
|January — April||7||<0.05|
|Source: NOAA FAQ|
Climatology does serve to characterize the general properties of an average season and can be used as one of many other tools for making forecasts. Most storms form in warm waters several hundred miles north of the equator near the Intertropical convergence zone from tropical waves. The Coriolis force is usually too weak to initiate sufficient rotation near the equator. Storms frequently form in the warm waters of the Gulf of Mexico, the Caribbean Sea, and the tropical Atlantic Ocean as far east as the Cape Verde Islands, the origin of strong and long-lasting Cape Verde-type hurricanes. Systems may also strengthen over the Gulf Stream off the coast of the eastern United States, wherever water temperatures exceed 26.5 °C (79.7 °F).
Although most storms are found within tropical latitudes, occasionally storms will form further north and east from disturbances other than tropical waves such as cold fronts and upper-level lows. These are known as baroclinically induced tropical cyclones. There is a strong correlation between Atlantic hurricane activity in the tropics and the presence of an El Niño or La Niña in the Pacific Ocean. El Niño events increase the wind shear over the Atlantic, producing a less-favorable environment for formation and decreasing tropical activity in the Atlantic basin. Conversely, La Niña causes an increase in activity due to a decrease in wind shear.
According to the Azores High hypothesis by Kam-biu Liu, an anti-phase pattern is expected to exist between the Gulf of Mexico coast and the North American Atlantic coast. During the quiescent periods (3000–1400 BC, and 1000 AD to present), a more northeasterly position of the Azores High would result in more hurricanes being steered toward the Atlantic coast. During the hyperactive period (1400 BC to 1000 AD), more hurricanes were steered towards the Gulf coast as the Azores High was shifted to a more southwesterly position near the Caribbean. Such a displacement of the Azores High is consistent with paleoclimatic evidence that shows an abrupt onset of a drier climate in Haiti around 3200 14C years BP, and a change towards more humid conditions in the Great Plains during the late-Holocene as more moisture was pumped up the Mississippi Valley through the Gulf coast. Preliminary data from the northern Atlantic coast seem to support the Azores High hypothesis. A 3000-year proxy record from a coastal lake in Cape Cod suggests that hurricane activity has increased significantly during the past 500–1000 years, just as the Gulf coast was amid a quiescent period of the last millennium.
Climatologically speaking, approximately 97 percent of tropical cyclones that form in the North Atlantic develop between the dates of June 1 and November 30 – dates which delimit the modern-day Atlantic hurricane season. Though the beginning of the annual hurricane season has historically remained the same, the official end of the hurricane season has shifted from its initial date of October 31. Regardless, on average once every few years a tropical cyclone develops outside the limits of the season; as of January 2016 there have been 68 tropical cyclones in the off-season, with the most recent being Subtropical Storm Alberto in 2018. The first tropical cyclone of the 1938 Atlantic hurricane season, which formed on January 3, became the earliest forming tropical storm and hurricane after reanalysis concluded on the storm in December 2012.
Hurricane Able in 1951 was initially thought to be the earliest forming major hurricane – a tropical cyclone with winds exceeding 115 mph (185 km/h)[nb 1] – however following post-storm analysis it was determined that Able only reached Category 1 strength which made Hurricane Alma of 1966 the new record holder; as it became a major hurricane on June 8. Though it developed within the bounds of the Atlantic hurricane season, Hurricane Audrey in 1957 became the earliest developing Category 4 hurricane on record after it reached the intensity on June 27. However, reanalysis from 1956 to 1960 by NOAA downgraded Audrey to a Category 3, making Hurricane Dennis of 2005 the earliest Category 4 on record on July 8, 2005. The earliest-forming Category 5 hurricane, Emily, reached the highest intensity on the Saffir–Simpson hurricane wind scale on July 17, 2005.
Though the official end of the Atlantic hurricane season occurs on November 30, the dates of October 31 and November 15 have also historically marked the official end date for the hurricane season. December, the only month of the year after the hurricane season, has featured the cyclogenesis of fourteen tropical cyclones. Tropical Storm Zeta in 2005 was the latest tropical cyclone to attain tropical storm intensity as it did so on December 30. However, the second Hurricane Alice in 1954 was the latest forming tropical cyclone to attain hurricane intensity. Both Zeta and Alice were the only two storms to exist in two calendar years – the former from 1954 to 1955 and the latter from 2005 to 2006. No storms have been recorded to exceed Category 1 hurricane intensity in December. In 1999, Hurricane Lenny reached Category 4 intensity on November 17 as it took an unprecedented west to east track across the Caribbean; its intensity made it the latest developing Category 4 hurricane, though this was well within the bounds of the hurricane season. Hurricane Hattie (October 27-November 1, 1961) was initially thought to have been the latest forming Category 5 hurricane ever documented, though reanalysis indicated that a devastating hurricane in 1932 reached such an intensity at a later date. Consequently, this made the hurricane the latest developing tropical cyclone to reach all four Saffir–Simpson hurricane wind scale classifications past Category 1 intensity.
The beginning of the hurricane season is most closely related to the timing of increases in sea surface temperatures, convective instability, and other thermodynamic factors. Although June marks the beginning of the hurricane season, generally little activity occurs during the month with an average of 1 tropical cyclone every 2 years. Tropical systems usually form in the Gulf of Mexico or off the east coast of the United States.
Since 1851, a total of 81 tropical storms and hurricanes formed in the month of June. During this period, two of these systems developed in the deep tropics east of the Lesser Antilles. Since 1870, three major hurricanes have formed during June, most notably Hurricane Audrey in 1957. Audrey attained an intensity greater than that of any Atlantic tropical cyclone during June or July until Hurricanes Dennis and Emily of 2005. The easternmost forming storm during June, Tropical Storm Ana in 1979, formed at 45°W.
Not much tropical activity occurs during the month of July, but the majority of hurricane seasons see the formation of one tropical cyclone during July. From an average of Atlantic tropical cyclone seasons from 1944 to 1996, the first tropical storm in half of the seasons occurred by 11 July, and a second formed by 8 August.
Formation usually occurs in the eastern Caribbean Sea around the Lesser Antilles, in the northern and eastern parts of the Gulf of Mexico, in the vicinity of the northern Bahamas, and off the coast of The Carolinas and Virginia over the Gulf Stream. Storms travel westward through the Caribbean and then either move towards the north and curve near the eastern coast of the United States or stay on a north-westward track and enter the Gulf of Mexico.
Since 1851, a total of 105 tropical storms have formed during the month of July. Since 1870, ten of these storms reached major hurricane intensity. Only Hurricane Emily of 2005, the strongest July tropical cyclone in the Atlantic basin, attained Category 5 hurricane status during July, making it the earliest Category 5 hurricane on record. The easternmost forming storm and longest lived during the month of July, Hurricane Bertha in 2008, formed at 22.9°W and lasted 17 days.
Decrease in wind shear from July to August contributes to a significant increase of tropical activity. An average of 2.8 Atlantic tropical storms develop annually in August. On average, four named tropical storms, including one hurricane, occur by August 30, and the first intense hurricane develops by 4 September.
The peak of the hurricane season occurs in September and corresponds with low wind shear and the warmest sea surface temperatures. The month of September sees an average of 3 storms a year. By 24 September, the average Atlantic season features 7 named tropical storms, including 4 hurricanes. In addition, two major hurricanes occur on average by 28 September. Relatively few tropical cyclones make landfall at these intensities.
The favorable conditions found during September begin to decay in October. The main reason for the decrease in activity is increasing wind shear, although sea surface temperatures are also cooler than in September. Activity falls markedly with 1.8 cyclones developing on average despite a climatological secondary peak around 20 October. By 21 October, the average season features 9 named storms with 5 hurricanes. A third major hurricane occurs after 28 September in half of all Atlantic tropical cyclone seasons. In contrast to mid-season activity, the mean locus of formation shifts westward to the Caribbean and Gulf of Mexico, reversing the eastward progression of June through August.
Wind shear from westerlies increases substantially through November, generally preventing cyclone formation. On average, one tropical storm forms during every other November. On rare occasions, a major hurricane occurs. The few intense hurricanes in November include Hurricane "Cuba" in late October and early November 1932 (the strongest November hurricane on record peaking as a Category 5 hurricane), Hurricane Lenny in mid-November 1999, Hurricane Kate in late November 1985 which was the latest major hurricane formation on record until Hurricane Otto (a category 3 storm) of the 2016 hurricane season. Hurricane Paloma was a very potent category 4 storm that made landfall in Cuba in early November 2008.
Although the hurricane season is defined as beginning on June 1 and ending on November 30, there have been several off-season storms. Since 1870, there have been 32 off-season cyclones, 18 of which occurred in May. In the same time span, nine storms formed in December, two in April, and one each in January, February and March. During four years (1887, 1953, 2003, and 2007), tropical cyclones formed in the North Atlantic Ocean both during or before May and during December. In 1887, four storms occurred outside the season, the most in a single year. High vertical wind shear and low sea surface temperatures generally preclude tropical cyclone formation during the off-season.
Tropical cyclones have formed in all months. Four tropical cyclones existed during the month of January, two of which formed during late December: the second Hurricane Alice in 1954/1955, and Tropical Storm Zeta in 2005/2006. The only two hurricanes to form in January are a Category 1 hurricane in the 1938 season, and Hurricane Alex in the 2016 season. A subtropical storm in January also began the 1978 Atlantic hurricane season. No major hurricanes have occurred in the off-season.
While the number of storms in the Atlantic has increased since 1995, there is no obvious global trend. The annual number of tropical cyclones worldwide remains about 87 ± 10. However, the ability of climatologists to make long-term data analysis in certain basins is limited by the lack of reliable historical data in some basins, primarily in the Southern Hemisphere. In spite of that, there is some evidence that the intensity of hurricanes is increasing. In 2006, Kerry Emanuel stated, "Records of hurricane activity worldwide show an upswing of both the maximum wind speed in and the duration of hurricanes. The energy released by the average hurricane (again considering all hurricanes worldwide) seems to have increased by around 70% in the past 30 years or so, corresponding to about a 15% increase in the maximum wind speed and a 60% increase in storm lifetime." At the time, Emanuel theorized that increased heat from global warming was driving this trend, however, some argue that Emanuel's own research in 2008 refuted this theory. Others contend that the trend does not exist at all, but instead is a figment created by faulty readings from primitive 1970s-era measurement equipment. Vecchi and Knutson (2008) found a weakly positive, although not statistically-significant trend in the number of North Atlantic tropical cyclones for 1878–2006, but also a surprisingly strong decrease in cyclone duration over this period.
On May 15, 2014, the journal Nature published a peer-reviewed submission from October 2013 by James P. Kossin, Kerry A. Emanuel, and Gabriel A. Vecchi that suggests that a poleward migration exists for the paths of maximum intensity of tropical cyclone activity in the Atlantic. The focus of the report is on the latitude at which recent tropical cyclones in the Atlantic are reaching maximum intensity. Their data indicates that during the past thirty years, the peak intensity of these storms has shifted poleward in both hemispheres at a rate of approximately 60 km per decade, amounting to approximately one degree of latitude per decade.
Atlantic storms are becoming more destructive financially, since five of the ten most expensive storms in United States history have occurred since 1990. According to the World Meteorological Organization, “recent increase in societal impact from tropical cyclones has largely been caused by rising concentrations of population and infrastructure in coastal regions.” Pielke et al. (2008) normalized mainland U.S. hurricane damage from 1900–2005 to 2005 values and found no remaining trend of increasing absolute damage. The 1970s and 1980s were notable because of the extremely low amounts of damage compared to other decades. The decade 1996–2005 has the second most damage among the past 11 decades, with only the decade 1926–1935 surpassing its costs. The most damaging single storm is the 1926 Miami hurricane, with $157 billion of normalized damage.
Often in part because of the threat of hurricanes, many coastal regions had sparse population between major ports until the advent of automobile tourism; therefore, the most severe portions of hurricanes striking the coast may have gone unmeasured in some instances. The combined effects of ship destruction and remote landfall severely limit the number of intense hurricanes in the official record before the era of hurricane reconnaissance aircraft and satellite meteorology. Although the record shows a distinct increase in the number and strength of intense hurricanes, therefore, experts regard the early data as suspect. Christopher Landsea et al. estimated an undercount bias of zero to six tropical cyclones per year between 1851 and 1885 and zero to four per year between 1886 and 1910. These undercounts roughly take into account the typical size of tropical cyclones, the density of shipping tracks over the Atlantic basin, and the amount of populated coastline.
The number and strength of Atlantic hurricanes may undergo a 50–70 year cycle, also known as the Atlantic Multidecadal Oscillation. Nyberg et al. reconstructed Atlantic major hurricane activity back to the early eighteenth century and found five periods averaging 3–5 major hurricanes per year and lasting 40–60 years, and six other averaging 1.5–2.5 major hurricanes per year and lasting 10–20 years. These periods are associated with the Atlantic multidecadal oscillation. Throughout, a decadal oscillation related to solar irradiance was responsible for enhancing/dampening the number of major hurricanes by 1–2 per year.
Although more uncommon since 1995, few above-normal hurricane seasons occurred during 1970–94. Destructive hurricanes struck frequently from 1926–60, including many major New England hurricanes. Twenty-one Atlantic tropical storms formed in 1933, a record only recently exceeded in 2005, which saw 28 storms. Tropical hurricanes occurred infrequently during the seasons of 1900–25; however, many intense storms formed during 1870–99. During the 1887 season, 19 tropical storms formed, of which a record 4 occurred after November 1 and 11 strengthened into hurricanes. Few hurricanes occurred in the 1840s to 1860s; however, many struck in the early 19th century, including an 1821 storm that made a direct hit on New York City. Some historical weather experts say these storms may have been as high as Category 4 in strength.
These active hurricane seasons predated satellite coverage of the Atlantic basin. Before the satellite era began in 1960, tropical storms or hurricanes went undetected unless a reconnaissance aircraft encountered one, a ship reported a voyage through the storm, or a storm landed in a populated area. The official record, therefore, could miss storms in which no ship experienced gale-force winds, recognized it as a tropical storm (as opposed to a high-latitude extra-tropical cyclone, a tropical wave, or a brief squall), returned to port, and reported the experience.
Proxy records based on paleotempestological research have revealed that major hurricane activity along the Gulf of Mexico coast varies on timescales of centuries to millennia. Few major hurricanes struck the Gulf coast during 3000–1400 BC and again during the most recent millennium. These quiescent intervals were separated by a hyperactive period during 1400 BC and 1000 AD, when the Gulf coast was struck frequently by catastrophic hurricanes and their landfall probabilities increased by 3–5 times. This millennial-scale variability has been attributed to long-term shifts in the position of the Azores High, which may also be linked to changes in the strength of the North Atlantic Oscillation.
According to the Azores High hypothesis, an anti-phase pattern is expected to exist between the Gulf of Mexico coast and the Atlantic coast. During the quiescent periods, a more northeasterly position of the Azores High would result in more hurricanes being steered towards the Atlantic coast. During the hyperactive period, more hurricanes were steered towards the Gulf coast as the Azores High was shifted to a more southwesterly position near the Caribbean. Such a displacement of the Azores High is consistent with paleoclimatic evidence that shows an abrupt onset of a drier climate in Haiti around 3200 14C years BP, and a change towards more humid conditions in the Great Plains during the late-Holocene as more moisture was pumped up the Mississippi Valley through the Gulf coast. Preliminary data from the northern Atlantic coast seem to support the Azores High hypothesis. A 3,000-year proxy record from a coastal lake in Cape Cod suggests that hurricane activity increased significantly during the past 500–1000 years, just as the Gulf Coast was amid a quiescent period during the last millennium. Evidence also shows that the average latitude of hurricane impacts has been steadily shifting northward, towards the Eastern Seaboard over the past few centuries. This change has been sped up in modern times due to the Arctic Ocean heating up especially much from fossil fuel-caused global warming.
The 1983 Atlantic hurricane season was the least active Atlantic hurricane season in 53 years, during which only four tropical storms formed. 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 1950, but not since 1900.
The season began later than normal; the first tropical depression formed on July 29 and the second on July 31. Neither tropical depressions strengthened and they dissipated soon thereafter. Hurricane Alicia formed as Tropical Depression Three on August 15, quickly intensified into a hurricane on August 16 and made landfall in Texas on August 18. Alicia caused $3 billion in damage in Texas. Hurricane Barry formed on August 25, crossed Florida and strengthened into a hurricane. Barry made landfall near the Mexico–United States border, and dissipated over land on August 30.
Hurricane Chantal, the third and final hurricane in 1983, formed on September 10. It strengthened into a hurricane, but stayed out at sea, and became absorbed by a front on September 15. Tropical Depression Six formed on September 19 and caused heavy rains in the Caribbean before degenerating into a wave on September 21. Tropical Storm Dean was the final storm of the season, forming on September 26. It originally tracked to the north, peaking at 55 mph (89 km/h) winds (85 km/h), and made landfall in the Delmarva Peninsula on September 29. It dissipated over the coast of Virginia on September 30.1991 Atlantic hurricane season
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.
The most significant storm of the season was Hurricane Bob, which at the time was among the ten costliest United States hurricanes. After brushing the Outer Banks of North Carolina and Long Island in New York, the hurricane made landfall on Rhode Island. It caused $1.5 billion in damage (1991 USD), mostly in Massachusetts, and 17 fatalities. The strongest hurricane of the season was Claudette, which reached peak winds of 135 mph (215 km/h) near Bermuda. It passed near the island but did not cause any damage. Tropical Storm Fabian was the only tropical storm to move over or near Cuba or Florida, producing heavy rainfall but no damage. Hurricane Grace, the final named storm of the season, provided the energy that led to the development of a powerful nor'easter known as the Perfect Storm. Originating from an extratropical storm, the Perfect Storm intensified while moving westward toward New England, leaving $200 million in damage and causing coastal damage from Puerto Rico to Florida and northward through Canada. It later transitioned into a hurricane over the Gulf Stream, finally dissipating over Nova Scotia on November 2.1994 Atlantic hurricane season
The 1994 Atlantic hurricane season was the final season in the most recent low-activity era (“cold phase”) of tropical cyclone formation in the Atlantic. It produced seven named tropical cyclones and three hurricanes, a total below the seasonal average. The season officially started on June 1 and ended on November 30, dates which conventionally limit the period during which most tropical cyclones form in the Atlantic Ocean. The first tropical cyclone, Tropical Storm Alberto, developed on June 30, while the last storm, Hurricane Gordon, dissipated on November 21. The season was unusual in that it produced no major hurricanes, which are those of Category 3 status or higher on the Saffir–Simpson hurricane scale. The most intense hurricane, Hurricane Florence, peaked as a Category 2 storm with winds of 110 mph (180 km/h). Aside from Chris, Florence, and Gordon, none of the storms exceeded tropical storm intensity.
Tropical Storm Alberto produced significant rainfall and flooding in the Southeastern United States, damaging or destroying over 18,000 homes. In August, Tropical Storm Beryl produced heavy rainfall in Florida, Georgia, South Carolina, and North Carolina, with moderate to heavy rainfall throughout several other states. Beryl caused numerous injuries, many of which occurred from a tornado associated with the tropical storm. Tropical Storm Debby killed nine people in the Caribbean in September. Hurricane Gordon was the most significant storm of the season, causing damage from Costa Rica to North Carolina among its six landfalls. Extreme flooding and mudslides from Gordon caused approximately 1,122 fatalities in Haiti. In addition, a nor'easter in December may have had tropical characteristics, though due to the uncertainty, it was not classified as a tropical system.2001 Atlantic hurricane season
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 most intense storm was Hurricane Michelle, which attained Category 4 strength on the Saffir–Simpson Hurricane Scale.
The most damaging storms of the season were Tropical Storm Allison, which caused extensive flooding in Texas, Hurricane Iris, which struck Belize, and Hurricane Michelle, which affected several countries. Three tropical cyclones made landfall on the United States, three directly affected Canada, and three directly affected Mexico and Central America. Overall, the season caused 117 fatalities, and $11.3 billion (2001 USD) in damage. Due to their severe damage, the names Allison, Iris, and Michelle were retired by the World Meteorological Organization.2002 Atlantic hurricane season
The 2002 Atlantic hurricane season was a slightly below-average Atlantic hurricane season. It officially started on June 1, 2002 and ended on November 30, dates which conventionally limit the period of each year when most tropical cyclones develop in the Atlantic Ocean. The season produced fourteen tropical cyclones, of which twelve developed into named storms; four became hurricanes, and two attained major hurricane status. While the season's first cyclone did not develop until July 14, activity quickly picked up; the 2002 season tied with 2010 in which a record number of tropical storms, eight, developed in the month of September. It ended early however, with no tropical storms forming after October 6—a rare occurrence caused partly by El Niño conditions. The most intense hurricane of the season was Hurricane Isidore with a minimum central pressure of 934 mbar, although Hurricane Lili attained higher winds and peaked at Category 4 whereas Isidore only reached Category 3. The season's low activity is reflected in the low cumulative accumulated cyclone energy (ACE) rating of 67. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so low number reflects the small number of strong storms and preponderance of tropical storms.
The season was less destructive than normal, causing an estimated $2.47 billion (2002 USD) in property damage and 23 fatalities.
Most destruction was due to Isidore, which caused about $1.28 billion (2002 USD) in damage and killed seven people in the Yucatán Peninsula and later the United States, and Hurricane Lili, which caused $1.16 billion (2002 USD) in damage and 15 deaths as it crossed the Caribbean Sea and eventually made landfall in Louisiana.2003 Atlantic hurricane season
The 2003 Atlantic hurricane season was a very active Atlantic hurricane season with tropical activity before and after the official bounds of the season—the first such occurrence since the 1964 season. The season produced 21 tropical cyclones, of which 16 developed into named storms; seven cyclones attained hurricane status, of which three reached major hurricane status. With sixteen storms, the season was tied for the sixth-most active Atlantic hurricane season on record. 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 $5.5 billion in damage (2003 USD) and a total of 51 deaths across the Mid-Atlantic region of the United States.
The season began with Subtropical Storm Ana on April 20, prior to the official start of the season; the bounds of the season are from June 1 to November 30, which conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. In early September, Hurricane Fabian struck Bermuda as a Category 3 hurricane, where it was the worst hurricane since 1926; on the island it caused four deaths and $300 million in damage (2003 USD). Hurricane Juan caused considerable destruction to Nova Scotia, particularly Halifax, as a Category 2 hurricane, the first hurricane of significant strength to hit the province since 1893. Additionally, Hurricanes Claudette and Erika struck Texas and Mexico, respectively, as minimal hurricanes.2004 Atlantic hurricane season
The 2004 Atlantic hurricane season was a very deadly, destructive, and hyperactive Atlantic hurricane season, with over 3,000 deaths and more than $60 billion (2004 USD) in damage. More than half of the 16 tropical cyclones brushed or struck the United States. Due to the development of a Modoki El Niño – a rare type of El Niño in which unfavorable conditions are produced over the eastern Pacific instead of the Atlantic basin due to warmer sea surface temperatures farther west along the equatorial Pacific – activity was above average. The season officially began on June 1 and ended on November 30, though the season's last storm, Otto, dissipated on December 3, extending the season beyond its traditional boundaries. The first storm, Alex, developed offshore of the Southeastern United States on July 31, one of the latest dates on record to see the formation of the first system in an Atlantic hurricane season. It brushed the Carolinas and the Mid-Atlantic, causing one death and $7.5 million (2004 USD) in damage. Several storms caused only minor damage, including tropical storms Bonnie, Earl, Hermine, and Matthew. In addition, hurricanes Danielle, Karl, and Lisa, Tropical Depression Ten, Subtropical Storm Nicole and Tropical Storm Otto had no effect on land while tropical cyclones.
There are four notable storms: Hurricane Charley, that made landfall in Florida as a Category 4 hurricane on the Saffir–Simpson hurricane wind scale (SSHWS), causing $16 billion in damage in the United States alone. Later in August, Hurricane Frances struck the Bahamas and Florida, causing at least 49 deaths and $10.1 billion in damage. The costliest and most intense storm was Hurricane Ivan. It was a Category 5 hurricane that devastated multiple countries adjacent to the Caribbean Sea, before entering the Gulf of Mexico and causing catastrophic damage on the Gulf Coast of the United States, especially in the states of Alabama and Florida. Throughout the countries it passed through, Ivan caused 129 fatalities and over $26.1 billion in damage. The deadliest storm was Hurricane Jeanne. In Haiti, torrential rainfall in the mountainous areas resulted in mudslides and severe flooding, causing at least 3,006 fatalities. Jeanne also struck Florida, inflicting extensive destruction. Overall, the storm caused at least $7.94 billion in damage and 3,042 deaths, ranking it as one of the deadliest Atlantic hurricanes in history.
Collectively, the storms of this season caused at least 3,270 deaths and about $61.2 billion in damage, making it the costliest Atlantic hurricane season at the time, until surpassed by the following year, 2012, and then 2017. With six hurricanes reaching at least Category 3 intensity, 2004 also had the most major hurricanes since 1996. However, that record would also be surpassed in 2005, with seven major hurricanes that year. In the spring of 2005, four names were retired: Charley, Frances, Ivan, and Jeanne. This tied the then-record most names retired with 1955 and 1995, while five were retired in 2005.2005 Atlantic hurricane season
The 2005 Atlantic hurricane season was the most active Atlantic hurricane season in recorded history, shattering numerous records. The impact of the season was widespread and catastrophic. Its storms caused an estimated total of 3,913 deaths and approximately $180.7 billion in damage, making it the second costliest season on record, surpassed only by the 2017 season.
Of the storms that made landfall, five of the season's seven major hurricanes—Dennis, Emily, Katrina, Rita, and Wilma—were responsible for the majority of the destruction. Stan was the most destructive storm that was not a major hurricane. The Mexican states of Quintana Roo and Yucatán and the U.S. states of Florida and Louisiana were each struck twice by major hurricanes; Cuba, the Bahamas, Haiti, Mississippi, Texas, Alabama, and Tamaulipas were each struck once and brushed by at least one more.
The most devastating effects of the season were felt on the United States' Gulf Coast, where a 30-foot (9.1 m) storm surge from Hurricane Katrina caused severe flooding that destroyed most structures on the Mississippi coastline; subsequent levee failures in New Orleans, Louisiana caused by the storm crippled the city. Furthermore, Hurricane Stan combined with an extratropical system to cause deadly mudslides across Central America, with Guatemala being hardest-hit.
The 2005 season was the first to observe more tropical storms and cyclones in the Atlantic than in the West Pacific; on average, the latter experiences 26 tropical storms per year while the Atlantic only averages 12. This event was repeated in the 2010 season; however, the 2010 typhoon season broke the record for the fewest storms observed in a single year, while the 2005 typhoon season featured near-average activity.
The season officially began on June 1, 2005, and lasted until November 30, although it effectively persisted into January 2006 due to continued storm activity. A record twenty-eight tropical and subtropical storms formed, of which a record fifteen became hurricanes. Of these, a record-tying seven strengthened into major hurricanes, a record-tying five became Category 4 hurricanes and a record four reached Category 5 strength, the highest categorization for hurricanes on the Saffir-Simpson Hurricane Scale. Among these Category 5 storms were hurricanes Katrina and Wilma, respectively the second costliest and the most intense (by lowest barometric pressure) Atlantic hurricanes on record. The 2005 season was also notable because the annual pre-designated list of storm names was used up and six Greek letter names had to be used.2006 Atlantic hurricane season
The 2006 Atlantic hurricane season was the least active since 1997 as well as 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 2005, forecasters predicted that the 2006 season would be only slightly less active. Instead 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.Tropical Storm Alberto was indirectly responsible for two deaths when it made landfall in Florida. Hurricane Ernesto caused heavy rainfall in Haiti, and directly killed at least seven in Haiti and the United States. Four hurricanes formed after Ernesto, including the strongest storms of the season, Hurricanes Helene and Gordon. In total, the season was responsible for 14 deaths and $500 million (2006 USD; $621 million 2019 USD) in damage. The calendar year 2006 also saw Tropical Storm Zeta, which arose in December 2005 and persisted until early January, only the second such event on record. The storm can be considered a part of the 2005 and 2006 seasons, although it occurred outside the June 1 – November 30 period during which most Atlantic basin tropical cyclones form.2007 Atlantic hurricane season
The 2007 Atlantic hurricane season was an above average Atlantic hurricane season, but most of the storms were weak and short-lived. Despite the high activity of weak storms during 2007, it was the first season to feature more than one Category 5 landfalling hurricane, a feat that would not be matched until ten years later. It produced 17 tropical cyclones, 15 tropical storms, six hurricanes, and two major hurricanes. It officially started on June 1 and ended on November 30, dates which conventionally delimit the period during which most tropical cyclones form in the Atlantic Ocean, although as shown by Subtropical Storm Andrea and Tropical Storm Olga in early May and early December, respectively, the formation of tropical cyclones is possible at any time of the year. The first system, Subtropical Storm Andrea, developed on May 9, while the last storm, Tropical Storm Olga, dissipated on December 13. The most intense hurricane, Dean, is tied for the eighth most intense Atlantic hurricane ever recorded as well as the third most intense Atlantic hurricane at landfall. The season was one of only six on record for the Atlantic with more than one Category 5 hurricane. It was the second on record in which an Atlantic hurricane, Felix, and an eastern Pacific hurricane, Henriette, made landfall on the same day. September had a record-tying eight storms, although the strengths and durations of most of the storms were low. Aside from hurricanes Dean and Felix, none of the storms in the season exceeded Category 1 intensity.
Pre-season forecasts by Colorado State University called for 14 named storms and 7 hurricanes, of which three were expected to attain major hurricane status. The National Oceanic and Atmospheric Administration (NOAA) later issued its initial forecast, which predicted 13 to 17 named storms, 7 to 10 hurricanes and three to five major hurricanes. After several revisions in the projected number of storms, NOAA and CSU lowered their forecasts by the middle of the season.
Several storms made landfall or directly affected land. Hurricanes Dean and Felix made landfall at Category 5 intensity, causing severe damage in parts of Mexico and Central America, respectively. Both storm names, as well as Noel, the name of a hurricane that affected the Caribbean, were retired from the naming list of Atlantic hurricanes. The United States was affected by five cyclones, although the storms were generally weak; three tropical depressions and only two tropical storms, Barry and Gabrielle, and one hurricane, Humberto, made landfall in the country. Elsewhere, three storms directly affected Canada, although none severely. The combined storms killed at least 478 people and caused about $3.42 billion (2007 USD, $4.13 billion 2019 USD) in damage.2008 Atlantic hurricane season
The 2008 Atlantic hurricane season was the most disastrous Atlantic hurricane season since 2005, causing over 1,000 deaths and nearly $50 billion in damages. It was an above-average season, featuring sixteen named storms, eight of which became hurricanes, and five which further became major hurricanes, the highest amount since the record-breaking 2005 season. It officially started on June 1 and ended on November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. However, the formation of Tropical Storm Arthur caused the season to start one day early. This season is the fifth most costly on record, behind only the 2004, 2005, 2012 and 2017 seasons, with over $49.5 billion in damage (2008 USD). It was the only year on record in which a major hurricane existed in every month from July through November in the North Atlantic.Bertha became the longest-lived July tropical cyclone on record for the basin, the first of several long-lived systems during 2008.
The season was devastating for Haiti, where over 800 people were killed by four consecutive tropical cyclones (Fay, Gustav, Hanna, and Ike), especially Hurricane Hanna, in August and September. Hurricane Paloma's outer rain bands also made landfall over Haiti. Ike was also the most destructive storm of the season, as well as the strongest in terms of minimum barometric pressure, devastating Cuba as a major hurricane and later making landfall near Galveston, Texas as a large high-end Category 2 hurricane. One very unusual feat was a streak of tropical cyclones affecting land. All but one system impacted land in 2008. The unprecedented number of storms with impact led to one of the deadliest and destructive seasons in the history of the Atlantic basin, especially with Ike, as its overall damages made it the second-costliest hurricane in the Atlantic at the time, although it would later drop to sixth after hurricanes Sandy, Harvey, Irma, and Maria.2009 Atlantic hurricane season
The 2009 Atlantic hurricane season was a below-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 (75 km/h) before quickly dissipating over Alabama. The storm killed two people and caused $228,000 (2009 USD) in damage.
Pre-season forecasts issued by Colorado State University (CSU) called for fourteen named storms and seven hurricanes, of which three were expected to attain major hurricane status. The National Oceanic and Atmospheric Administration (NOAA) later issued its initial forecast, which predicted nine to fourteen named storms, four to seven hurricanes, and one to three major hurricanes. After several revisions in the projected number of named storms, both agencies lowered their forecasts by the middle of the season.
Several storms made landfall or directly affected land outside of the United States. Tropical Storm Ana brought substantial rainfall totals to many of the Caribbean islands, including Puerto Rico, which led to minor street flooding. Hurricane Bill delivered gusty winds and rain to the island of Newfoundland, while Tropical Storm Danny affected the U.S. state of North Carolina, and Erika affected the Lesser Antilles as a poorly organized tropical system. Hurricane Fred affected the Cape Verde Islands as a developing tropical cyclone and Tropical Storm Grace briefly impacted the Azores, becoming the farthest northeast forming storm on record. The season's final storm, Ida, affected portions of Central America before bringing significant rainfall to the Southeast United States as an extratropical cyclone.2017 Atlantic hurricane season
The 2017 Atlantic hurricane season was a hyperactive and catastrophic hurricane season that, with a damage total of at least $282.27 billion (USD), was the costliest tropical cyclone season on record. With over 3,300 estimated deaths, 2017 was the deadliest season since 2005 and also featured both the highest total accumulated cyclone energy (ACE) and the highest number of major hurricanes since 2005. About 99.7% of the season's damage was due to three of the season's major hurricanes – Harvey, Irma, and Maria. Another notable hurricane, Nate, was the worst natural disaster in Costa Rican history; Harvey, Irma, Maria, and Nate had their names retired due to their high damage costs and loss of life. Featuring 17 named storms, 10 hurricanes, and 6 major hurricanes, the 2017 season ranks alongside 1936 as the fifth-most active season since reliable records began in 1851.
This season is also one of only six years on record to feature multiple Category 5 hurricanes, and only the second after 2007 to feature two hurricanes making landfall at that intensity. All ten of the season's hurricanes occurred in a row, the greatest number of consecutive hurricanes in the satellite era, and tied for the greatest number of consecutive hurricanes ever observed in the Atlantic basin since reliable records began in 1851. Additionally, this season is the only season on record in which three hurricanes each had an ACE of over 40: Irma, Jose, and Maria.
The season officially began on June 1 and ended on November 30. These dates historically describe the period of year when most tropical cyclones form in the Atlantic basin. However, as shown by Tropical Storm Arlene in April, the formation of tropical cyclones is possible at other times of the year. In mid-June, Tropical Storm Bret struck the island of Trinidad, which is rarely struck by tropical cyclones, due to its low latitude. In late August, Hurricane Harvey became the first major hurricane to make landfall in the United States since Wilma in 2005 and the first Category 4 hurricane since Charley in 2004, while also tying the record for the costliest tropical cyclone on record, as well as the most rainfall dropped by a tropical cyclone in the United States. In early September, Hurricane Irma became the first Category 5 hurricane to impact the northern Leeward Islands on record, later making landfall in the Florida Keys as a Category 4 hurricane. In terms of maximum sustained winds, Irma is the strongest hurricane ever recorded in the Atlantic Ocean outside of the Gulf of Mexico and Caribbean Sea. In late September, Hurricane Maria became the first Category 5 hurricane to strike the island of Dominica on record. It later made landfall in Puerto Rico as a high-end Category 4 hurricane with catastrophic effect. Most of the deaths from this season occurred from Maria, and caused a humanitarian crisis in Puerto Rico. In early October, Hurricane Nate became the fastest-moving tropical cyclone in the Gulf of Mexico while also becoming the fourth hurricane of the year to make landfall in the contiguous United States. Slightly over a week later, Hurricane Ophelia became the easternmost major hurricane in the Atlantic basin on record, and later impacted most of Northern Europe as an extratropical cyclone. The season concluded with Tropical Storm Rina, which became a post-tropical cyclone on November 9, although the season did not officially end until November 30.
Initial predictions for the season anticipated that an El Niño would develop, lowering tropical cyclone activity. However, the predicted El Niño failed to develop, with cool-neutral conditions developing instead, later progressing to a La Niña – the second one in a row. This led forecasters to raise their predicted totals, with some later anticipating that the season could be the most active since 2010.
Beginning in 2017, the National Hurricane Center (NHC) had the option to issue advisories, and thus allow watches and warnings to be issued, on disturbances that are not yet tropical cyclones but have a high chance to become one, and are expected to bring tropical storm or hurricane conditions to landmasses within 48 hours. Such systems are termed "Potential Tropical Cyclones". The first storm to receive this designation was Potential Tropical Cyclone Two, which later developed into Tropical Storm Bret, east-southeast of the Windward Islands on June 18. In addition, the numbering that a potential tropical cyclone receives would be retained for the rest of the hurricane season, meaning that the next tropical system would be designated with the following number, even though potential tropical cyclones do not qualify as tropical cyclones. This was first demonstrated with Potential Tropical Cyclone Ten, which failed to develop into a tropical cyclone.2018 Atlantic hurricane season
The 2018 Atlantic hurricane season was the third in a consecutive series of above-average and damaging Atlantic hurricane seasons, featuring 15 named storms, 8 hurricanes and 2 major hurricanes and a total of $33.3 billion (2018 USD) in damages. The season officially began on June 1, 2018, and ended on November 30, 2018. These dates historically describe the period each year when most tropical cyclones form in the Atlantic basin and are adopted by convention. However, tropical cyclogenesis is possible at any time of the year, as shown by the formation of Tropical Storm Alberto on May 25, which marked the fourth consecutive year in which a storm developed before the official start of the season. The next storm, Beryl, became the first hurricane to form in the eastern Atlantic during the month of July since Bertha in 2008. Chris, upgraded to a hurricane on July 10, became the earliest second hurricane in a season since 2005. No hurricanes formed in the Atlantic during the month of August, marking the first season since 2013, and the eighth season on record, to do so. On September 5, Florence became the first major hurricane of the season. On September 12, Joyce formed, making 2018 the first season since 2008 to feature four named storms active simultaneously (Florence, Helene, Isaac, and Joyce). On October 9, Michael became the second major hurricane of the season, and a day later, it became the third-most intense hurricane to make landfall on the United States in terms of pressure, behind the 1935 Labor Day hurricane and Hurricane Camille of 1969. With the formation of Oscar on October 27, the season is the first on record to see seven storms that were subtropical at some point in their lifetimes (Alberto, Beryl, Debby, Ernesto, Joyce, Leslie, and Oscar).
Most forecasting groups called for a below-average season due to cooler than normal sea surface temperatures in the tropical Atlantic and the anticipated development of an El Niño. However, the anticipated El Niño failed to develop in time to suppress activity, and activity exceeded most predictions.Atlantic hurricane reanalysis project
The Atlantic hurricane reanalysis project of the National Oceanic and Atmospheric Administration seeks to correct and add new information about past North Atlantic hurricanes. It was started around 2000 to update HURDAT, the official hurricane database for the Atlantic Basin, which has become outdated since its creation due to various systematic errors introduced into the database over time. This effort has involved reanalyses of ship observations from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) as well as reanalyses done by other researchers over the years. It has been ongoing as of 2016, and should last another four years.Atlantic hurricane season
The Atlantic hurricane season is the period in a year when hurricanes usually form in the Atlantic Ocean. Tropical cyclones in the North Atlantic are called hurricanes, tropical storms, or tropical depressions. In addition, there have been several storms over the years that have not been fully tropical and are categorized as subtropical depressions and subtropical storms. Even though subtropical storms and subtropical depressions are not technically as strong as tropical cyclones, the damages can still be devastating.
Worldwide, tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures is the greatest. However, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active. In the Northern Atlantic Ocean, a distinct hurricane season occurs from June 1 to November 30, sharply peaking from late August through September; the season's climatological peak of activity occurs around September 10 each season. This is the norm, but in 1938, the Atlantic hurricane season started as early as January 3.
Tropical disturbances that reach tropical storm intensity are named from a pre-determined list. On average, 10.1 named storms occur each season, with an average of 5.9 becoming hurricanes and 2.5 becoming major hurricanes (Category 3 or greater). The most active season was 2005, during which 28 tropical cyclones formed, of which a record 15 became hurricanes. The least active season was 1914, with only one known tropical cyclone developing during that year.
The Atlantic hurricane season is a time when most tropical cyclones are expected to develop across the northern Atlantic Ocean. It is currently defined as the time frame from June 1 through November 30, though in the past the season was defined as a shorter time frame. During the season, regular tropical weather outlooks are issued by the National Hurricane Center, and coordination between the Weather Prediction Center and National Hurricane Center occurs for systems which have not formed yet, but could develop during the next three to seven days.List of Atlantic hurricanes in the 18th century
The List of Atlantic hurricanes in the 18th century encompasses all known Atlantic tropical cyclones from 1700 to 1799. Although not all of the data for every storm that occurred are available, some parts of the coastline were populated enough to provide data of hurricane occurrences.South Atlantic tropical cyclone
South Atlantic tropical cyclones are unusual weather events that occur in the Southern Hemisphere. Strong wind shear, which disrupts the formation of cyclones, as well as a lack of weather disturbances favorable for development in the South Atlantic Ocean make any strong tropical system extremely rare, and Hurricane Catarina in 2004 is the only recorded South Atlantic hurricane in history. South Atlantic storms have developed year-round, with activity peaking during the months from November through May in this basin. Since 2011, the Brazilian Navy Hydrographic Center has started to assign names to tropical and subtropical systems in the western side of the basin near Brazil, when they have sustained wind speeds of at least 65 km/h (40 mph), the generally accepted minimum sustained wind velocity for a disturbance to be designated as a tropical storm in the North Atlantic basin. Below is a list of notable South Atlantic tropical and subtropical cyclones.Tropical cyclone naming
Tropical cyclones and subtropical cyclones are named by various warning centers to provide ease of communication between forecasters and the general public regarding forecasts, watches, and warnings. The names are intended to reduce confusion in the event of concurrent storms in the same basin. Generally once storms produce sustained wind speeds of more than 33 knots (61 km/h; 38 mph), names are assigned in order from predetermined lists depending on which basin they originate. However, standards vary from basin to basin: some tropical depressions are named in the Western Pacific, while tropical cyclones must have a significant amount of gale-force winds occurring around the centre before they are named in the Southern Hemisphere.
Before the formal start of naming, tropical cyclones were named after places, objects, or saints' feast days on which they occurred. The credit for the first usage of personal names for weather systems is generally given to the Queensland Government Meteorologist Clement Wragge, who named systems between 1887 and 1907. This system of naming weather systems subsequently fell into disuse for several years after Wragge retired, until it was revived in the latter part of World War II for the Western Pacific. Formal naming schemes and naming lists have subsequently been introduced and developed for the Eastern, Central, Western and Southern Pacific basins, as well as the Australian region, Atlantic Ocean and Indian Ocean.