From a Shapiro–Keyser extratropical cyclone to the subtropical cyclone Raoni: An unusual winter synoptic situation over the South Atlantic Ocean
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Petrobras The eastern coast of South America is a cyclogenetic region in terms of extratropical cyclones and, in lower number, of subtropical cyclones that are mor...
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Online Access: | http://hdl.handle.net/11449/240677 https://doi.org/10.1002/qj.4349 |
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ftunivespir:oai:repositorio.unesp.br:11449/240677 2023-07-02T03:33:43+02:00 From a Shapiro–Keyser extratropical cyclone to the subtropical cyclone Raoni: An unusual winter synoptic situation over the South Atlantic Ocean Reboita, Michelle Simões Gozzo, Luiz Felippe Crespo, Natália Machado Custodio, Maria de Souza Lucyrio, Vinícius Jesus, Eduardo Marcos de Rocha, Rosmeri Porfírio da Universidade Estadual Paulista (UNESP) 2022-07-01 2991-3009 http://hdl.handle.net/11449/240677 https://doi.org/10.1002/qj.4349 eng eng Quarterly Journal of the Royal Meteorological Society http://dx.doi.org/10.1002/qj.4349 Quarterly Journal of the Royal Meteorological Society, v. 148, n. 747, p. 2991-3009, 2022. 1477-870X 0035-9009 http://hdl.handle.net/11449/240677 doi:10.1002/qj.4349 2-s2.0-85136231941 cyclone phases numerical experiments South Atlantic Ocean subtropical cyclone synoptic evolution warm seclusion info:eu-repo/semantics/article 2022 ftunivespir https://doi.org/10.1002/qj.4349 2023-06-12T17:45:16Z Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Petrobras The eastern coast of South America is a cyclogenetic region in terms of extratropical cyclones and, in lower number, of subtropical cyclones that are more frequent in austral summer and autumn. However, in June 2021, an unusual cyclone developed near the boundary of Uruguay and southern Brazil, initially having extratropical features and later undergoing a subtropical transition. At 1200 UTC 29 June, the Brazilian Navy named it as subtropical cyclone Raoni. This study aims to describe the synoptic evolution of the cyclone and address physical drivers for the subtropical transition based on the ECMWF-ERA5 reanalysis and numerical experiments with the WRF model. The cyclone precursor of Raoni had its genesis at 1800 UTC 26 June 2021 forced by a trough at mid–upper levels that crossed the Andes Mountains and caused a rapid surface pressure drop. Less than 24 hr later, the cyclone presented a frontal T-bone pattern and warm seclusion, following the Shapiro–Keyser development model. Strong surface heat fluxes, a deep moist troposphere, and the vertical alignment of the warm seclusion with an upper-level cut-off pattern provided the adequate environment for organising convection and, consequently, for subtropical transition at 0600 UTC 28 June. The fundamental role of the surface turbulent heat fluxes for the transition is confirmed through numerical experiments. This study is unprecedented in the sense that no subtropical cyclone originating from a warm seclusion has been documented over the South Atlantic before. These findings emphasise the need of monitoring cold-season extratropical Shapiro–Keyser cyclones in the region since they can evolve to a subtropical or tropical cyclone and can cause damage to the maritime activities and coastal region due to the strong winds. Article in Journal/Newspaper South Atlantic Ocean Universidade Estadual Paulista São Paulo: Repositório Institucional UNESP Austral Uruguay Quarterly Journal of the Royal Meteorological Society 148 747 2991 3009 |
institution |
Open Polar |
collection |
Universidade Estadual Paulista São Paulo: Repositório Institucional UNESP |
op_collection_id |
ftunivespir |
language |
English |
topic |
cyclone phases numerical experiments South Atlantic Ocean subtropical cyclone synoptic evolution warm seclusion |
spellingShingle |
cyclone phases numerical experiments South Atlantic Ocean subtropical cyclone synoptic evolution warm seclusion Reboita, Michelle Simões Gozzo, Luiz Felippe Crespo, Natália Machado Custodio, Maria de Souza Lucyrio, Vinícius Jesus, Eduardo Marcos de Rocha, Rosmeri Porfírio da From a Shapiro–Keyser extratropical cyclone to the subtropical cyclone Raoni: An unusual winter synoptic situation over the South Atlantic Ocean |
topic_facet |
cyclone phases numerical experiments South Atlantic Ocean subtropical cyclone synoptic evolution warm seclusion |
description |
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Petrobras The eastern coast of South America is a cyclogenetic region in terms of extratropical cyclones and, in lower number, of subtropical cyclones that are more frequent in austral summer and autumn. However, in June 2021, an unusual cyclone developed near the boundary of Uruguay and southern Brazil, initially having extratropical features and later undergoing a subtropical transition. At 1200 UTC 29 June, the Brazilian Navy named it as subtropical cyclone Raoni. This study aims to describe the synoptic evolution of the cyclone and address physical drivers for the subtropical transition based on the ECMWF-ERA5 reanalysis and numerical experiments with the WRF model. The cyclone precursor of Raoni had its genesis at 1800 UTC 26 June 2021 forced by a trough at mid–upper levels that crossed the Andes Mountains and caused a rapid surface pressure drop. Less than 24 hr later, the cyclone presented a frontal T-bone pattern and warm seclusion, following the Shapiro–Keyser development model. Strong surface heat fluxes, a deep moist troposphere, and the vertical alignment of the warm seclusion with an upper-level cut-off pattern provided the adequate environment for organising convection and, consequently, for subtropical transition at 0600 UTC 28 June. The fundamental role of the surface turbulent heat fluxes for the transition is confirmed through numerical experiments. This study is unprecedented in the sense that no subtropical cyclone originating from a warm seclusion has been documented over the South Atlantic before. These findings emphasise the need of monitoring cold-season extratropical Shapiro–Keyser cyclones in the region since they can evolve to a subtropical or tropical cyclone and can cause damage to the maritime activities and coastal region due to the strong winds. |
author2 |
Universidade Estadual Paulista (UNESP) |
format |
Article in Journal/Newspaper |
author |
Reboita, Michelle Simões Gozzo, Luiz Felippe Crespo, Natália Machado Custodio, Maria de Souza Lucyrio, Vinícius Jesus, Eduardo Marcos de Rocha, Rosmeri Porfírio da |
author_facet |
Reboita, Michelle Simões Gozzo, Luiz Felippe Crespo, Natália Machado Custodio, Maria de Souza Lucyrio, Vinícius Jesus, Eduardo Marcos de Rocha, Rosmeri Porfírio da |
author_sort |
Reboita, Michelle Simões |
title |
From a Shapiro–Keyser extratropical cyclone to the subtropical cyclone Raoni: An unusual winter synoptic situation over the South Atlantic Ocean |
title_short |
From a Shapiro–Keyser extratropical cyclone to the subtropical cyclone Raoni: An unusual winter synoptic situation over the South Atlantic Ocean |
title_full |
From a Shapiro–Keyser extratropical cyclone to the subtropical cyclone Raoni: An unusual winter synoptic situation over the South Atlantic Ocean |
title_fullStr |
From a Shapiro–Keyser extratropical cyclone to the subtropical cyclone Raoni: An unusual winter synoptic situation over the South Atlantic Ocean |
title_full_unstemmed |
From a Shapiro–Keyser extratropical cyclone to the subtropical cyclone Raoni: An unusual winter synoptic situation over the South Atlantic Ocean |
title_sort |
from a shapiro–keyser extratropical cyclone to the subtropical cyclone raoni: an unusual winter synoptic situation over the south atlantic ocean |
publishDate |
2022 |
url |
http://hdl.handle.net/11449/240677 https://doi.org/10.1002/qj.4349 |
geographic |
Austral Uruguay |
geographic_facet |
Austral Uruguay |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_relation |
Quarterly Journal of the Royal Meteorological Society http://dx.doi.org/10.1002/qj.4349 Quarterly Journal of the Royal Meteorological Society, v. 148, n. 747, p. 2991-3009, 2022. 1477-870X 0035-9009 http://hdl.handle.net/11449/240677 doi:10.1002/qj.4349 2-s2.0-85136231941 |
op_doi |
https://doi.org/10.1002/qj.4349 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
148 |
container_issue |
747 |
container_start_page |
2991 |
op_container_end_page |
3009 |
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1770273784334385152 |