An Australian region tropical cyclone is a non-

frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music * The Front (band), an American rock band signed to Columbia Records and active in the 1980s and e ...

low-pressure system In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...

that has developed within an environment of warm

sea surface temperature Sea surface temperature (SST), or ocean surface temperature, is the ocean temperature close to the surface. The exact meaning of ''surface'' varies according to the measurement method used, but it is between and below the sea surface. Air mas ...

s and little vertical

wind shear Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizont ...

aloft in either the Southern

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...

or the South

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

. Within the Southern Hemisphere there are officially three areas where tropical cyclones develop on a regular basis: the South-West Indian Ocean between Africa and 90°E, the Australian region between 90°E and 160°E, and the South Pacific basin between 160°E and 120°W. The Australian region between 90°E and 160°E is officially monitored by the Australian

Bureau of Meteorology The Bureau of Meteorology (BOM or BoM) is an executive agency of the Australian Government responsible for providing weather services to Australia and surrounding areas. It was established in 1906 under the Meteorology Act, and brought together ...

, the Indonesian

Meteorology, Climatology, and Geophysical Agency Meteorology, Climatology, and Geophysical Agency ( id, Badan Meteorologi, Klimatologi, dan Geofisika, abbreviated BMKG) is an Indonesian non-departmental government agency for meteorology, climatology, and geophysics. History Its history began ...

, and the Papua New Guinea National Weather Service, while others like the

Fiji Meteorological Service The Fiji Meteorological Service (FMS) is a Department of the government of Fiji responsible for providing weather forecasts and is based on the grounds of Nadi Airport in Nadi. The current director of Fiji Meteorological Service is Misaeli Funak ...

and the United States

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...

also monitor the basin. Each tropical cyclone year within this basin starts on 1 July and runs throughout the year, encompassing the tropical cyclone season, which runs from 1 November and lasts until 30 April each season. Within the basin, most tropical cyclones have their origins within the

South Pacific convergence zone The South Pacific Convergence Zone (SPCZ), a reverse-oriented monsoon trough, is a band of low-level convergence, cloudiness and precipitation extending from the Western Pacific Warm Pool at the maritime continent south-eastwards towards French Pol ...

or within the Northern Australian monsoon trough, both of which form an extensive area of cloudiness and are dominant features of the season. Within this region a tropical disturbance is classified as a tropical cyclone when it has 10-minute sustained wind speeds of more than 65 km/h (35 mph) that wrap halfway around the low level circulation centre, while a severe tropical cyclone is classified when the maximum 10-minute sustained wind speeds are greater than 120 km/h (75 mph).

Basin history

There is a history of tropical cyclones affecting northeastern Australia for over 5000 years; however,

Clement Lindley Wragge Clement Lindley Wragge (18 September 185210 December 1922) was a meteorologist born in Stourbridge, Worcestershire, England, but moved to Oakamoor, Staffordshire as a child. He set up the Wragge Museum in Stafford following a trip around the wor ...

was the first person to monitor and name them. In the early history of tropical cyclones in the Australian region, the only evidence of a storm was based on ship reports and observations from land. Later, satellite imagery began in the basin in the 1959-60 season, although it was not continuous until 1970. In

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

in particular, the lack of population centers, shipping lanes, radars, and offshore stations meant that storms were tracked infrequently. After the onset of satellite imagery, the

Dvorak technique The Dvorak technique (developed between 1969 and 1984 by Vernon Dvorak) is a widely used system to estimate tropical cyclone intensity (which includes tropical depression, tropical storm, and hurricane/typhoon/intense tropical cyclone intensitie ...

was used to estimate storms' intensities and locations. Each of three tropical cyclone warning centres (TCWCs) of the Bureau of Meteorology in

Perth Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth i ...

, Darwin and

Brisbane Brisbane ( ) is the capital and most populous city of the Australian state of Queensland, and the third-most populous city in Australia and Oceania, with a population of approximately 2.6 million. Brisbane lies at the centre of the South ...

used its own tropical cyclone naming list until the 2008–09 season, when the three TCWCs started to use the single Australian national naming list. From the 2020–21 season, the three TCWCs were unified into one single TCWC which still monitors all tropical cyclones that form within the Australian region, including any within the areas of responsibility of TCWC Jakarta or TCWC

Port Moresby (; Tok Pisin: ''Pot Mosbi''), also referred to as Pom City or simply Moresby, is the capital and largest city of Papua New Guinea. It is one of the largest cities in the southwestern Pacific (along with Jayapura) outside of Australia and New ...

. Later in 2021, the Australian tropical cyclone warning centre was officially named as TCWC Melbourne.

Background

The Australian region is currently defined as being between 90°E and 160°E, and is monitored by five different warning centres during the season, which runs from 1 November to 30 April.

Australian tropical cyclone outlook regions

The

defines four regions within the Australian region which are used when the bureau issues tropical cyclone seasonal outlooks every year. These four regions are named the Western region, the Northwestern sub-region, the Northern region and the Eastern region. The Australian region overall averages eleven tropical cyclones in a season, and the bureau assesses the region as a whole to have a high level of accuracy when forecasting tropical cyclone activity. The Western region encompasses the area east of 90°E and west of 125°E. The region covers the eastern

including the

Cocos (Keeling) Islands ) , anthem = "''Advance Australia Fair''" , song_type = , song = , image_map = Australia on the globe (Cocos (Keeling) Islands special) (Southeast Asia centered).svg , map_alt = Location of the Cocos (Keeling) Islands , map_caption = ...

and

Christmas Island Christmas Island, officially the Territory of Christmas Island, is an Australian external territory comprising the island of the same name. It is located in the Indian Ocean, around south of Java and Sumatra and around north-west of the ...

, and waters off

west of

Kuri Bay Kuri Bay is a remote coastal bay in the far north of Western Australia in the Kimberley region, about north of Broome. It is a designated point on the Western Australian Forecast Areas, utilised by the Bureau of Meteorology as a boundary for ...

. The region also covers waters off Indonesia that include the main islands of

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...

, Bali,

Lombok Lombok is an island in West Nusa Tenggara province, Indonesia. It forms part of the chain of the Lesser Sunda Islands, with the Lombok Strait separating it from Bali to the west and the Alas Strait between it and Sumbawa to the east. It is ...

Sumbawa Sumbawa is an Indonesian island, located in the middle of the Lesser Sunda Islands chain, with Lombok to the west, Flores to the east, and Sumba further to the southeast. Along with Lombok, it forms the province of West Nusa Tenggara, but th ...

, Sumba, Flores and the western half of

Timor Timor is an island at the southern end of Maritime Southeast Asia, in the north of the Timor Sea. The island is divided between the sovereign states of East Timor on the eastern part and Indonesia on the western part. The Indonesian part, also ...

. The region averages seven tropical cyclones in a season, and the bureau assesses the region to have a low level of accuracy when forecasting tropical cyclone activity. The Northwestern sub-region encompasses the area east of 105°E, west of 130°E and north of 25°S. The sub-region covers waters off Western Australia north of Shark Bay, and extends westward to Christmas Island. The sub-region also covers waters off Indonesia as far west as Java and as far east as Timor. The sub-region averages five tropical cyclones in a season, and the bureau assesses the sub-region to have a moderate level of accuracy when forecasting tropical cyclone activity. The Northern region encompasses the area east of 125°E and west of 142.5°E. The region covers the

Timor Sea The Timor Sea ( id, Laut Timor, pt, Mar de Timor, tet, Tasi Mane or ) is a relatively shallow sea bounded to the north by the island of Timor, to the east by the Arafura Sea, and to the south by Australia. The sea contains a number of reefs ...

, the

Banda Sea The Banda Sea ( id, Laut Banda, pt, Mar de Banda, tet, Tasi Banda) is one of four seas that surround the Maluku Islands of Indonesia, connected to the Pacific Ocean, but surrounded by hundreds of islands, including Timor, as well as the Halma ...

, the

Arafura Sea The Arafura Sea (or Arafuru Sea) lies west of the Pacific Ocean, overlying the continental shelf between Australia and Western New Guinea (also called Papua), which is the Indonesian part of the Island of New Guinea. Geography The Arafura S ...

and the Gulf of Carpentaria. The region averages three tropical cyclones in a season, and the bureau assesses the region to have a very low level of accuracy when forecasting tropical cyclone activity. The Eastern region encompasses the area east of 142.5°E and west of 160°E. The region covers waters east of

Torres Strait The Torres Strait (), also known as Zenadh Kes, is a strait between Australia and the Melanesian island of New Guinea. It is wide at its narrowest extent. To the south is Cape York Peninsula, the northernmost extremity of the Australian mai ...

and includes the Coral Sea and the

Tasman Sea The Tasman Sea ( Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer ...

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland P ...

lies within the region, but Norfolk Island lies east of the region, although the bureau continues to monitor tropical cyclones when they are a threat to the external territory. The region also covers waters off

Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...

and western parts of the

Solomon Islands Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capit ...

. The region averages four tropical cyclones in a season, and the bureau assesses the region to have a low level of accuracy when forecasting tropical cyclone activity.

Seasons

Before 1900

1900–1909

1910–1919

1920–1929

1930–1939

1940–1949

1950–1959

1960–1969

1970s

1980s

1990s

2000s

2010s

2020s

Notes

References

External links

Australian Bureau of Meteorology

Joint Typhoon Warning Center

Tropical Cyclone Warning Center Jakarta

{{DEFAULTSORT:List Of Australian Region Cyclone Seasons

Australian region cyclone seasons Australian(s) may refer to: Australia * Australia, a country * Australians, citizens of the Commonwealth of Australia ** European Australians ** Anglo-Celtic Australians, Australians descended principally from British colonists ** Aboriginal Aus ...