Post-tropical Cyclone - Wikipedia

A tropical cyclone that no longer possesses tropical characteristics

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages) The examples and perspective in this article may not represent a worldwide view of the subject. You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate. (February 2021) (Learn how and when to remove this message) The neutrality of this article is disputed. Relevant discussion may be found on the talk page. Please do not remove this message until conditions to do so are met. (August 2023) (Learn how and when to remove this message) (Learn how and when to remove this message)

A post-tropical cyclone is a former tropical cyclone that no longer possesses enough tropical qualities to be considered a tropical cyclone.[1] The word may refer to a former tropical cyclone undergoing extratropical transition or a tropical cyclone degenerating into a remnant low. A tropical cyclone degenerating into a trough or wave, or having its low level circulation dissipate overland, lacks a cyclonic circulation and is referred as remnants instead of a post-tropical cyclone. However, post-tropical cyclones or remnants can continue producing high winds and heavy rains.[2]

Classification/Other post-tropical cyclones

[edit]

Classes

[edit]

Two classes of post-tropical cyclones exist

• Extratropical cyclone, which is frontal, sometimes still retains winds of hurricane or tropical storm force.[1] Hurricane Paulette (2020) provides a recent example of an extratropical cyclone,[3] in which it no longer has a warm core in higher latitudes when it was over Nova Scotia and all points north in its trajectory.[4]
• Remnant low, which is non-frontal, has maximum sustained winds of less than 34 knots, and mainly consists of stable stratocumulus with little to no convective activity. These shallow systems may meander for some time before opening into a trough of low pressure, or by being absorbed into an extratropical cyclone.[1][5][6]

Other post-tropical cyclones

[edit]

Not all systems fall into the above two classes. According to the guideline, a system without frontal characteristics but with maximum winds above 34 knots may not be designated as a remnant low. It should be merely described as post-tropical.[7] A few examples falling into this grey area are listed below.

• Eugene (2011)[8]
• Michael (2012)[9]
• Nadine (2012)[10]
• Humberto (2013)[11]
• Joaquin (2015)[12]
• Matthew (2016)[13]
• Jerry (2019)[14]
• Paulette (2020)[15]
• Guambe (2021)
• Linda (2021)[16]
• Batsirai (2022)
• Emnati (2022)
• Blas (2022)[17]
• Frank (2022)[18]
• Howard (2022)[19]
• Kay (2022)[20]

However, there has been an occasion that the United States National Hurricane Center went against that definition and designated Calvin (2011) as a 35-knot remnant low.[21] Also, if a tropical cyclone degenerates into a tropical wave or trough, then it does not qualify as a post-tropical cyclone. It would be referred as the "remnants of (tropical cyclone name)".

Météo-France classifies systems in the South-West Indian Ocean undergoing an extratropical transition or losing tropical characteristics as "post-tropical depressions", since the 2012–13 cyclone season. They would be re-classified as extratropical depressions after completing the process.[22]

Formation

[edit]

A post-tropical cyclone is formed when the typical characteristics of a tropical cyclone are replaced with those of extratropical cyclones, otherwise known as extratropical transition.[23] After the initial formation, a post-tropical cyclone has the potential to gain strength and intensity by forming an extratropical storm.[23] If a post-tropical cyclone does become an extratropical storm, it will eventually decay through the process of occlusion.[24]

Impacts

[edit]

The re-intensification of a post-tropical cyclone can cause dangerous conditions in North Atlantic shipping routes with high seas and winds comparable to those of hurricanes.[23]

Origin

[edit]

The terminology was initiated by Meteorologist Peter Bowyer of the Canadian Hurricane Centre in 1998 during Tropical Storm Bonnie.[25] In 2008, the National Hurricane Center used this term for Tropical Storm Laura to address the limitation of the two classes (extratropical/remnant low) mentioned above.[26] The term was later adopted by the National Weather Service on May 15, 2010.[7]

Synonym

[edit]

The Bureau of Meteorology in Australia refers to a former tropical cyclone as an "ex-tropical cyclone".[27] An example is ex-tropical cyclone Oswald.

See also

[edit]

• Glossary of tropical cyclone terms

References

[edit]

1. ^ a b c "Glossary of NHC Terms". www.nhc.noaa.gov.
2. ^ "Glossary of NHC Terms". www.nhc.noaa.gov. Retrieved 2021-01-25.
3. ^ "Post-Tropical Cyclone Dorian Forecast+Discussion". www.nhc.noaa.gov. Retrieved 2019-09-07.
4. ^ "Dorian causing damage in Canada after losing 'hurricane' status". 8 September 2019.
5. ^ Zelinsky, David A.; Pasch, Richard J. (2015-01-30). Hurricane Marie (PDF) (Report). Archived (PDF) from the original on 2022-12-17.
6. ^ "Post-Tropical Cyclone MARIE". www.nhc.noaa.gov. Retrieved 2021-02-19.
7. ^ a b "SERVICE CHANGE NOTICE 10-06". Nws.noaa.gov. National Weather Service. January 15, 2010. Archived from the original on October 30, 2012. Retrieved 13 October 2017.
8. ^ "Post-Tropical Cyclone EUGENE". National Hurricane Center.
9. ^ "Post-Tropical Cyclone MICHAEL". National Hurricane Center.
10. ^ "Post-Tropical Cyclone NADINE". National Hurricane Center.
11. ^ "Post-Tropical Cyclone HUMBERTO". www.nhc.noaa.gov.
12. ^ "Post-Tropical Cyclone JOAQUIN". National Hurricane Center.
13. ^ "Post-Tropical Cyclone MATTHEW". National Hurricane Center. Retrieved 2016-10-09.
14. ^ "Post-Tropical Cyclone JERRY". National Hurricane Center. Retrieved 2019-09-28.
15. ^ "Post-Tropical Cyclone PAULETTE". www.nhc.noaa.gov. Retrieved 2022-11-16.
16. ^ "Post-Tropical Cyclone LINDA". www.nhc.noaa.gov. Retrieved 2022-11-16.
17. ^ Reinhart, Brad (June 20, 2022). Post-Tropical Cyclone Blas Advisory Number 26 (Report). Miami, Florida: National Hurricane Center. Retrieved June 20, 2022.
18. ^ "Post-Tropical Cyclone FRANK". www.nhc.noaa.gov. Retrieved 2022-11-16.
19. ^ "Post-Tropical Cyclone HOWARD". www.nhc.noaa.gov. Retrieved 2022-11-16.
20. ^ "Post-Tropical Cyclone KAY". www.nhc.noaa.gov. Retrieved 2022-11-16.
21. ^ http://www.nhc.noaa.gov/data/tcr/EP032011_Calvin.pdf
22. ^ "Saison 2012-2013" (in French). Météo-France. Retrieved 5 February 2018.
23. ^ a b c Pelissero, Jonathon; Chiao, Sen (July 5, 2013). "The influences of post-tropical reintensification and dissipation on North Atlantic shipping routes". Meteorological Applications. 21 (3). Royal Meteorological Society: 755. Bibcode:2014MeApp..21..755P. doi:10.1002/met.1410.
24. ^ "Extratropical Cyclone". britannica.com. Encyclopædia Britannica. Retrieved October 27, 2016.
25. ^ "Learn about hurricanes: Post-tropical cyclones". 16 June 2009.
26. ^ "Tropical Storm LAURA". www.nhc.noaa.gov.
27. ^ "Tropical Cyclone Outlook". Bureau of Meteorology.

v t e Cyclones and anticyclones of the world (centers of action)
Concepts	Anticyclonic storm Storm High-pressure area Low-pressure area Rapid intensification Explosive cyclogenesis Central dense overcast Annular tropical cyclone Bar (tropical cyclone) Superstorm Hypercane Tropical cyclones and climate change Post-tropical cyclone Sting jet List Rainband
Anticyclone	Northern Hemisphere North Polar High Siberian High Azores High North American High North Pacific High Ridiculously Resilient Ridge Subtropical ridge Southern Hemisphere Bolivian High South Polar High South Atlantic High South Pacific High Kalahari High Australian High Subtropical ridge
Cyclone	Synoptic scale Surface-based Polar North Polar low South Polar low Great Arctic Cyclone of 2012 Extratropical North America Continental Lee Cyclone Alberta clipper Colorado low Great Basin low Bighorn Low Other Panhandle hook November gale Oceanic Aleutian Low Hatteras low Nor'easter Gulf low Pacific Northwest windstorm Europe Icelandic Low Genoa low European windstorm Asia Asiatic Low Western Disturbance Continental North Asian storms East Asian-northwest Pacific storms Southern Hemisphere Southern Ocean cyclone Sudestada Subtropical Kona storm Australian east coast low Black nor'easter Lake Huron cyclone Mediterranean tropical-like cyclone Thermal Tropical (Outline) Northern Hemisphere Atlantic hurricane Cape Verde hurricane Pacific hurricane Typhoon North Indian Ocean tropical cyclone Mediterranean tropical-like cyclone Black Sea tropical-like cyclone Southern Hemisphere South-West Indian Ocean tropical cyclone Australian region tropical cyclone South Pacific tropical cyclone South Atlantic tropical cyclone Upper level Cold-core low Cut-off low Polar vortex Upper tropospheric cyclonic vortex Mesoscale Mesoscale ocean eddies Catalina eddy Haida Eddies Mesoscale convective system Wake Low Mesohigh Mesoscale convective vortex Line echo wave pattern Whirlwind Major Mesocyclone Supercell Low-topped supercell Wall cloud Funnel cloud Tornado Multiple-vortex tornado Satellite tornado Anticyclonic tornado Landspout Waterspout Minor Gustnado Dust devil Steam devil Fire whirl
Tropical cyclones portal Tornadoes portal