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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. Storms can develop year-round in the South Atlantic, with activity peaking during the months from November through May. Since 2011, the Brazilian Navy Hydrographic Center has assigned names to tropical and subtropical systems in the western side of the basin, near the eastern coast of Brazil, when they have sustained wind speeds of at least 65 km/h (40 mph), the generally accepted minimum sustained wind speed 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.

Climatology
It was initially thought that tropical cyclones did not develop within the South Atlantic. Very strong vertical wind shear in the troposphere is considered a deterrent. The Intertropical Convergence Zone drops one to two degrees south of the equator, not far enough from the equator for the Coriolis force to significantly aid development. Water temperatures in the tropics of the southern Atlantic are cooler than those in the tropical north Atlantic. Although they are rare, during April 1991 the United States' National Hurricane Center (NHC) reported that a tropical cyclone had developed over the Eastern South Atlantic. In subsequent years, a few systems were suspected to have the characteristics needed to be classified as a tropical cyclone, including in March 1994 and January 2004. During March 2004, an extratropical cyclone formally transitioned into a tropical cyclone and made landfall on Brazil, after becoming a Category 2 hurricane on the Saffir–Simpson hurricane wind scale. While the system was threatening the Brazilian state of Santa Catarina, a newspaper used the headline "Furacão Catarina", which was originally presumed to mean "furacão (hurricane) threatening (Santa) Catarina (the state)". After international presses started monitoring the system, "Hurricane Catarina" has formally been adopted. ==History and warning==
History and warning
At the Sixth WMO International Workshop on Tropical Cyclones (IWTC-VI) in 2006, it was questioned if any subtropical or tropical cyclones had developed within the South Atlantic before Catarina. During January 2009, a subtropical storm developed in the basin, and in March 2010, a tropical storm developed, which was named Anita by the Brazilian public and private weather services. In 2011, the Brazilian Navy Hydrographic Center started to assign names to tropical and subtropical cyclones that develop within its area of responsibility, to the west of 20°W, when they have sustained wind speeds of at least . In July 2025, at the 42nd Session of the International Civil Aviation Organization (ICAO) Assembly, the brazilian government expressed their intention to establish a Tropical Cyclone Advisory Centre (TCAC) in Rio de Janeiro for METAREA V, which comprises the western side of the South Atlantic ocean and includes the brazilian coastline, with the Centro Integrado de Meteorologia Aeronáutica (CIMAER) assuming the responsibilities for the region alongside the navy. The plan's goal is to integrate this TCAC into WMO's Tropical Cyclone Programme (TCP) and achieve operational status by December 2026. ==Notable storms and impacts==
Notable storms and impacts
Pre-2010s 1991 Angola tropical storm A low-pressure area formed over the Congo Basin on 9 April. The next day it moved offshore northern Angola with a curved cloud pattern. It moved westward over an area of warm waters while the circulation became better defined. According to the United States National Hurricane Center, the system was probably either a tropical depression or a tropical storm at its peak intensity. On 14 April, the system rapidly dissipated, as it was absorbed into a large squall line. This is the only recorded tropical cyclone in the eastern South Atlantic. Hurricane Catarina Hurricane Catarina was an extraordinarily rare hurricane-strength tropical cyclone, forming in the southern Atlantic Ocean in March 2004. Soon after becoming a hurricane, it hit the southern coast of Brazil in the state of Santa Catarina on the evening of 28 March, with winds up to making it a Category 2-equivalent cyclone on the Saffir–Simpson hurricane scale. Catarina killed 3 to 11 people and caused millions of dollars in damage in Brazil. At the time, Brazilians were taken completely by surprise, and were initially skeptical that an actual tropical cyclone could have formed in the South Atlantic. Eventually, however, they were convinced, and adopted the previously unofficial name "Catarina" for the storm, after Santa Catarina state. This event is considered by some meteorologists to be a nearly once-in-a-lifetime occurrence. 2010s Tropical Storm Anita On 8 March 2010, a previously extratropical cyclone developed tropical characteristics and was classified as a subtropical cyclone off the coast of southern Brazil. The following day, the United States Naval Research Laboratory began monitoring the system as a system of interest under the designation of 90Q. The National Hurricane Center also began monitoring the system as Low SL90. During the afternoon of 9 March, the system had attained an intensity of and a barometric pressure of 1000 hPa (mbar). It was declared a tropical storm on 10 March and became extratropical late on 12 March. Anita's accumulated cyclone energy was estimated at 2.0525 by the Florida State University. There was no damage associated to the storm, except high sea in the coasts of Rio Grande do Sul and Santa Catarina. Post mortem, the cyclone was given the name "Anita" by private and public weather centers in Southern Brazil. Subtropical Storm Arani Early on 14 March 2011, the Navy Hydrographic Center-Brazilian Navy (SMM), in coordination with the National Institute of Meteorology, were monitoring an organizing area of convection near the southeast coast of Brazil. Later that day a low-pressure area developed just east of Vitória, Espírito Santo, and by 12:00 UTC, the system organized into a subtropical depression, located about east of Campos dos Goytacazes. Guided by a trough and a weak ridge to its north, the system moved slowly southeastward over an area of warm waters, intensifying into Subtropical Cyclone Arani on 15 March, as named by the Brazilian Navy Hydrographic Center, and achieving its lowest pressure. The storm was classified as subtropical, as the convection was east of the center. On 16 March, Arani began experiencing of wind shear because another frontal system bumped it from behind. As it moved east-southeastwards, it achieved its highest winds as it transitioned back to an extratropical cyclone, process that was concluded on early 17 March. Increased swells along the coast prompted ocean travel warnings. Subtropical Depression #01-2015 On late 22 January 2015, instability areas formed well south of the state of Rio de Janeiro, associated with a trough attached with a low-pressure area active on the region. Early on the next day, over a region with anomalous warm sea surface temperatures, convection organized over a low-level center of circulation, which achieved its peak intensity of . For the rest of the day, the storm moved south and then turned southwestward, until it lost its subtropical characteristics over high seas on the next day, becoming a remnant low about to the east of Rio Grande do Sul, Brazil. During the next day, low-level baroclinity decreased around the system, as it moved southeastwards away from the Brazilian coast and into anomalously warm waters, where it intensified further. The system was named Bapo by the Brazilian Navy Hydrography Center during 6 February as it had intensified into a subtropical storm. Over the next couple of days the system continued to move south-eastwards, achieving its peak intensity just before it transitioned into an extratropical cyclone during 8 February. while the Center for Weather Forecast and Climatic Studies (CPTEC in Portuguese) already assigned the name Cari for the storm. At 00:00 UTC on 11 March, the Hydrographic Center of the Brazilian Navy upgraded Cari to a subtropical storm, also assigning this name to it. On 12 March, the Brazilian Hydrographic Center downgraded Cari to a subtropical depression as it achieved its lowest pressure, as it moved away from the continental coastline. Cari brought heavy rainfall, flooding and landslides to eastern cities of Santa Catarina and Rio Grande do Sul states as it interacted with a South Atlantic Convergence Zone. On the next day, while shfting from a westward movement to a southward one, other agencies considered the system an invest for possible tropical transition, designating it as 90Q. However, on 7 January, the system degenerated into a remnant low east of the state of Rio de Janeiro. Subtropical Storm Deni On 15 November 2016, instability areas associated with a trough axis over Rio de Janeiro's coastline led to the formation of a subtropical depression southwest of it. It intensified into a subtropical storm and received the name Deni on 16 November. Moving south-southeastwards, Deni soon became extratropical shortly before 00:00 UTC on 17 November, where it was absorbed by a mid-latitude frontal system. Later, it intensified quickly and then transitioned into a subtropical storm shortly before 22:00 BRST (00:00 UTC on 5 December), with the name Eçaí assigned by the Hydrographic Center of the Brazilian Navy. Eçaí started to decay on 5 December as it moved Into cooler waters, and weakened into a subtropical depression at around 00:00 UTC on 6 December. As it decayed and lost its subtropical characteristics, its center divided in two, with the new center moving away southeastwards and the old one degrading into a remnant frontal low. On 9 December a subtropical storm formed from this setup, on border between Espírito Santo and Bahia, moving southeastwards away from land. On late 10 December, a Cold front pushed Guará southwards towards cooler waters, where it started transitioning into an extratropical cyclone. shortly thereafter degenerating into a low-pressure area associated with a through axis. Tropical Storm Iba On 22 March 2019, a low-pressure area formed off the coast of Bahia after the passage of a frontal system. On the next day, the cyclone developed a deep warm-core, thus being designated as a tropical depression. On 24 March, the system intensified into a tropical storm, receiving the name Iba from the Brazilian Navy Hydrographic Center. Iba was the first tropical storm to develop in the basin since Anita in 2010, as well as the first fully tropical system to be named from the Brazilian naming list. Subtropical Storm Jaguar On 19 May 2019 several instability areas formed from a through axis off the coast of Espírito Santo, which later coalesced into a subtropical depression. On 20 May, the system strengthened into a subtropical storm, receiving the name Jaguar from the Brazilian Navy Hydrographic Center. However, the system did not intensify any further, as it soon encountered unfavorable conditions while moving southeastwards, weakening into a subtropical depression on early 21 May. Several hours later, due to a lack of wind shear, the system intensified into a subtropical storm and was given the name Kurumí. After this bout of intensification, Kurumí moved southward and began to succumb to much more unfavorable conditions. It weakened back to a subtropical depression on late 24 January, due to an intensification of wind shear over its circulation due to the formation of an extratropical cyclone to its southeast. The last advisory was issued on Kurumí later that same day, as it degenerated into a trough while also beginning to merge with the nearby frontal system. Subtropical Storm Mani On 24 October 2020, a trough axis persisted off the coast of the border between Espírito Santo and Bahia, which led to the formation of a subtropical depression on the next day. Later that day it intensified into a subtropical storm, which led it to be named Mani at 00:00 UTC on 26 October. As it moved away from a South Atlantic Convergence Zone on 27 October, Mani gradually lost its subtropical characteristics, until it weakened to a low pressure area. The storm caused significant damage in Espírito Santo, with landslides of stones and earth leaving more than 400 people homeless. The storm also impacted almost the entire state of Minas Gerais and the northern region of Rio de Janeiro. Subtropical Storm Oquira On 26 December 2020, the prior presence of a South Atlantic Convergence Zone and the subsequent passage of a frontal system led to the presence of several instability areas off the coast east of Rio Grande do Sul, which coalesced into a subtropical depression a day later. Moving southwestward, the system's central pressure dropped to by 00:00 UTC on 28 December. Later that day, the system's winds intensified, and it was named Oquira by the Brazilian Hydrographic Center. On 29 December, Oquira continued to strengthen, deepening while heading further southwestward away from the Brazilian mainland, and reaching a pressure of . Afterwards, Oquira's movements shifted southeastwards, and its winds decreased as it started to lose its subtropical characteristics, weakening to a subtropical depression on 30 December, but its pressure continued to drop, bottoming out at a minimum central pressure of . Later that day, Oquira transitioned into an extratropical low, and the Hydrographic Center issued their final advisory on the storm as it was absorbed by a frontal system. Tropical Storm 01Q On 4 February 2021, an extratropical storm off the coast of Rio Grande do Sul developed into a bomb cyclone. On 6 February, the storm began separating from its weather fronts and developed subtropical characteristics, before fully separating from the frontal zone and transitioning into a fully-tropical storm later that day. As a result, the NOAA classified the system as a tropical storm at 17:30 UTC, with the system being designated as Tropical Storm 01Q. However, the storm was short-lived, as it lost its tropical characteristics several hours later, with the NOAA issuing their final bulletin on the storm at 23:30 UTC that day. The storm dissipated soon afterward. Although the NOAA issued bulletins on the storm, the Hydrographic Center of the Brazilian Navy did not monitor it. Subtropical Depression #01-2021 On 13 February 2021, instability areas associated with a low-pressure area off the coast of the state of Rio Grande do Sul acquired subtropical characteristics on the next day, becoming a subtropical depression about from the state. For the next few days, the storm slowly meandered southeastward and then southwestward alongside a trough axis to its east, The Brazilian Navy noted in its post-season analysis that on late 14 February the system could have intensified into a subtropical storm, since the radiometer built into the AMSR-2 satellite found winds of 35 knots, but it wasn't upgraded because no other measurement confirmed such findings. On 20 April 2021, the system intensified into a subtropical storm, which Brazilian Navy then decided to name it Potira. Potira moved slowly northeastwards for a couple of days over unusually warmer waters, favorable upper-level tropospheric winds and strong low-level convergence, which led to its intensification and persistence of its peak intensity until 23 April. As it completed a clockwise loop, Potira weakened into a subtropical depression, with the Brazilian Navy downgrading it to a low-pressure area on late 24 January. The storm caused a gale in the Copacabana fort and the gusts of wind went over . In the municipalities of Balneário Camboriú and Florianópolis (SC), the hangover caused by Potira caused flooding in the streets and damage to the sidewalks. The ports of Itajaí and Navegantes were closed for 3 days. No economic or material damage caused by the cyclone has been reported. Subtropical Storm Raoni An extratropical cyclone formed on 26 June 2021, about east-southeast of Montevideo, Uruguay, associated with a cold airmass that acted over the region. On the next day, the cyclone acquired a warm seclusion while intensifying, while it moved westwards and separated from the frontal system it was previously attached to. It remained unnamed due to it being outside of the Brazilian Navy's area of responsibility. By 23:30 UTC on 28 June, the Satellite Products and Services Division of the NESDIS declared the system to have become a tropical storm, based on a Dvorak rating of 3.5, assigning an invest tag to it. At around 12:00 UTC on the next day, as the storm entered the boundary of METAREA V, Brazilian Navy's area of responsibility, thus it was assigned the name Raoni. Continuing moving northeastwards, Raoni further developed an eye feature as well as a robust band to the east of the system. Raoni began to weaken by 30 June, as the subtropical jet broke the barotropic flow over it, and NESDIS dropped the tag as it lost its convective bands. On 1 July, Raoni lost its subtropical characteristics and degenerated into a low-pressure area. The predecessor extratropical cyclone of Raoni caused heavy rains and strong winds gust up to , downing trees and causing damages to different public and private establishments across Punta del Este. The area's waters were also rough due to the storm. Downpours with continuous gales were also experienced in Uruguay's capital Montevideo. Subtropical Storm Ubá On 9 December 2021, instability areas remained off the coast of Espírito Santo and Rio de Janeiro after the passage of a frontal system and a South Atlantic Convergence Zone. Overnight the system coalesced into an occluded front, which transitioned into a subtropical depression. On the morning of the next day, the system was upgraded to subtropical storm status, receiving the name Ubá. On 11 December Ubá gradually weakened while moving southeastwards, being downgraded to depression status. The precursor extratropical cyclone and South Atlantic Convergence Zone caused heavy rains in Minas Gerais, Espírito Santo and southern Bahia, where heavy precipitation accumulated in Itamaraju and in Monte Formoso, killing fifteen people. The low occluded and separated form its precursor extratropical cyclone, obtaining subtropical characteristics in the process. Taking a more northwestwardly movement, Yakecan moved away from the coastline, gradually losing its subtropical characteristics. During its trajectory, the storm caused snow in the Gaúcha and Catarinense Mountains, setting record lows for this time of year. Two people died in Uruguay and Brazil due to the passage of the cyclone. Yakecan is the last name from the regular naming list, which has been in use since 2011. Subtropical Depression #01-2023 On late 6 January 2023, a subtropical depression formed from a quasi-stationary frontal system, about east of the state of Santa Catarina. On the next day, the system achieved its lowest pressure of as it moved southeastward, away from the frontal system while being enhanced by both anomally high sea-surface temperatures and the presence of a South Atlantic Convergence Zone (SACZ) on the vicinity. Tropical Storm Akará In February 2024, a low-pressure area began developing along a stalled cold front. Moisture from the tropics began feeding into the circulation of the developing disturbance, helping it to intensify. On 16 February 2024, the Brazilian Navy designated the system, which at the time was east southeast of Rio de Janeiro, Brazil, as a subtropical depression. Two days later, the system transitioned into a tropical cyclone. Early on 19 February, the system intensified into a tropical storm, receiving the name Akará from the Brazilian Navy. However, two days later, the system lost its tropical characteristics and weakened into a subtropical depression. The next day, the system lost its subtropical characteristics, thus the Brazilian Navy ceased all bulletins. Nova Iguaçu was affected with intense rainfall and winds. Akará was the first named tropical storm to develop in the basin since Iba in 2019. Subtropical Storm Biguá Early on 15 December 2024, a subtropical storm formed off the coast of the Brazil–Uruguay border, receiving the name Biguá from the Brazilian Navy. As it moved southeastwards, away from the coastline, the system was downgraded to subtropical depression. On early 17 December 2024, the cyclone was downgraded to a low-pressure area as it transitioned to an extratropical cyclone. The closeness to the Brazilian shore caused wind gusts over the southeastern Rio Grande do Sul, leading to power losses and structural damages on nearby cities. Subtropical Storm Caiobá {{Infobox tropical cyclone small On 2 March 2026, a subtropical depression formed just north of an already existing one, marking the first time in recorded history that two cyclones, either tropical or subtropical, have existed simultaneously in the South Atlantic. Later that day, the system strengthened into a subtropical storm and was named Caiobá. As it moved generally southeastwards, away from South America, it was last noted on late 3 March. ==Other systems==
Other systems
Pre-2004 According to a presentation at the Sixth WMO International Workshop on Tropical Cyclones (IWTC-VI), satellite imagery from January 1970 showed that a system with an eyewall had developed behind a cold front and that the system needed further analysis to determine if it was tropical or subtropical. Over the next 48 hours the system quickly developed further and was classified as subtropical, as it developed a banding structure and deep convection near its warm core. According to the Zambia Meteorological Department, Cyclone Bonita moved off the coast of Angola and entered the South Atlantic Ocean on 19 January 1996. By the next day, the system had succumbed to cold waters and days of land interaction, dissipating completely. It was the first tropical cyclone known to have traversed southern Africa from the South-West Indian Ocean to the South Atlantic. 2004–2009 During 2004, the large-scale conditions over the South Atlantic were more conducive than usual for subtropical or tropical systems, with 4 systems noted. Between 11 and 17 March 2006, another system with a warm core developed and moved southward along the South Atlantic Zone, before dissipating. The storm produced rainfall in 24 hours of or more in some locations of Rocha (Uruguay) and southern Rio Grande do Sul. The weather station owned by MetSul Weather Center in Morro Redondo, Southern Brazil, recorded in a 24-hour period. The storm caused fourteen deaths and the evacuation of thousands, with an emergency declared in four cities. 2010–2021 On 16 November 2010, a cold-core mid to upper-level trough in phase with a low-level warm-core low developed a low-pressure system over Brazil, and moved southeastward into the South Atlantic, where it slightly deepened. The system brought locally heavy rains in southern Brazil and northeast of Uruguay that exceeded 200 millimeters within a few hours, in some locations of Southern Rio Grande do Sul, northwest of Pelotas. Damages and flooding were observed in Cerrito, São Lourenço do Sul and Pedro Osório. Between 23 December 2013 and 24 January 2015, the CPTEC and Navy Hydrography Center monitored three additional subtropical depressions to the south of Rio de Janeiro. The first one lasted until Christmas Day, 2013. Two subtropical depressions formed in 2014: one in late-February 2014 and the other in late-March 2014. On 3 January 2021, according to the Météo-France, the remnants of Tropical Storm Chalane from the South-West Indian Ocean crossed southern Africa and briefly emerged into the eastern South Atlantic before dissipating. 2026–present On 28 February 2026, shortly before Caiobá's formation, a subtropical depression formed along the coastline of the State of Rio De Janeiro and Espírito Santo, and they coexisted between March 1 and 3 until the depression dissipated over open waters. ==Storm names==
Storm names
The following names are published by the Brazilian Navy Hydrographic Center's Marine Meteorological Service and used for tropical and subtropical storms that form in the area west of 20ºW and south of equator in the South Atlantic Ocean. Originally announced in 2011, In 2022, 32 new names were added after the previous ones were exhausted. The names are assigned in alphabetical order and used sequentially without regard to year. Retirements Kamby was replaced by Kurumí in 2018 without being used. == Climatological statistics ==
Climatological statistics
There have been 88 recorded tropical and subtropical cyclones in the South Atlantic Ocean since 1957. Like most southern hemisphere cyclone seasons, most of the storms have formed between November and May. DateFormat=yyyy ImageSize= width:350 height:auto barincrement:35 Period = from:0 till:18 TimeAxis = orientation:horizontal PlotArea = right:10 left:5 bottom:50 top:5 Colors= id:cat5red value:rgb(1,0.3765,0.3765) id:minorline value:rgb(0.9,0.9,0.9) id:line value:rgb(0.5,0.5,0.5) PlotData= width:15 textcolor:black shift:(5,-5) anchor:from fontsize:M bar:Jan from:0 till:11 color:cat5red text:"January" bar:Feb from:0 till:10 color:cat5red text:"February" bar:Mar from:0 till:12 color:cat5red text:"March" bar:Apr from:0 till:7 color:cat5red text:"April" bar:May from:0 till:11 color:cat5red text:"May" bar:Jun from:0 till:7 color:cat5red text:"June" bar:Jul from:0 till:5 color:cat5red text:"July" bar:Aug from:0 till:5 color:cat5red text:"August" bar:Sep from:0 till:5 color:cat5red text:"September" bar:Oct from:0 till:2 color:cat5red text:"October" bar:Nov from:0 till:9 color:cat5red text:"November" bar:Dec from:0 till:8 color:cat5red text:"December" ScaleMajor = gridcolor:line unit:year increment:3 start:0 ScaleMinor = gridcolor:minorline unit:year increment:1 start:0 TextData = fontsize:M textcolor:black pos:(50,25) # tabs:(100-left) text:"Number of storms in the South Atlantic Ocean" DateFormat=yyyy ImageSize= width:350 height:auto barincrement:35 Period = from:0 till:21 TimeAxis = orientation:horizontal PlotArea = right:10 left:5 bottom:50 top:5 Colors= id:cat5red value:rgb(1,0.3765,0.3765) id:minorline value:rgb(0.9,0.9,0.9) id:line value:rgb(0.5,0.5,0.5) PlotData= width:15 textcolor:black shift:(5,-5) anchor:from fontsize:M bar:1950s from:0 till:7 color:cat5red text:"1950s" bar:1960s from:0 till:13 color:cat5red text:"1960s" bar:1970s from:0 till:13 color:cat5red text:"1970s" bar:1980s from:0 till:3 color:cat5red text:"1980s" bar:1990s from:0 till:9 color:cat5red text:"1990s" bar:2000s from:0 till:19 color:cat5red text:"2000s" bar:2010s from:0 till:15 color:cat5red text:"2010s" bar:2020s from:0 till:15 color:cat5red text:"2020s" ScaleMajor = gridcolor:line unit:year increment:3 start:0 ScaleMinor = gridcolor:minorline unit:year increment:1 start:0 TextData = fontsize:M textcolor:black pos:(50,25) # tabs:(100-left) text:"Number of storms in South Atlantic Ocean" ==See also==
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