An Australian region tropical cyclone is a non- frontal, low-pressure system that has developed within an environment of warm sea surface temperatures and little vertical wind shear aloft in either the Southern

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

or the South

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

. 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 Government of Australia, Australian Government that is responsible for providing Weather forecasting, weather forecasts and Meteorology, meteorological services to Australia a ...

, the Indonesian Meteorology, Climatology, and Geophysical Agency, and the Papua New Guinea National Weather Service, while others like the Fiji Meteorological Service and the United States

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with Weather forecasting, forecasting weather, monitoring oceanic and atmospheric conditions, Hydrography, charting the seas, ...

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 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 at least 65 km/h (40 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 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 (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

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 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 list of Australian capital cities, capital city of Western Australia. It is the list of cities in Australia by population, fourth-most-populous city in Australia, with a population of over 2.3 million within Greater Perth . The ...

, Darwin and

Brisbane Brisbane ( ; ) is the List of Australian capital cities, capital and largest city of the States and territories of Australia, state of Queensland and the list of cities in Australia by population, third-most populous city in Australia, with a ...

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 Jakarta (; , Betawi language, Betawi: ''Jakartè''), officially the Special Capital Region of Jakarta (; ''DKI Jakarta'') and formerly known as Batavia, Dutch East Indies, Batavia until 1949, is the capital and largest city of Indonesia and ...

or TCWC Port Moresby. 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 and Christmas Island, and waters off

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

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

Bali Bali (English:; Balinese language, Balinese: ) is a Provinces of Indonesia, province of Indonesia and the westernmost of the Lesser Sunda Islands. East of Java and west of Lombok, the province includes the island of Bali and a few smaller o ...

, Lombok, Sumbawa, 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 Indonesia–Timor-Leste border, divided between the sovereign states of Timor-Leste in the eastern part and Indonesia in the ...

. 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

Banda Sea The Banda Sea (, , ) 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 Halmahera Sea, Halmahera and Ceram Seas. It is about ...

, the Arafura Sea and the

Gulf of Carpentaria The Gulf of Carpentaria is a sea off the northern coast of Australia. It is enclosed on three sides by northern Australia and bounded on the north by the eastern Arafura Sea, which separates Australia and New Guinea. The northern boundary ...

. 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 and includes the

Coral Sea The Coral Sea () is a marginal sea of the Pacific Ocean, South Pacific off the northeast coast of Australia, and classified as an Interim Biogeographic Regionalisation for Australia, interim Australian bioregion. The Coral Sea extends down t ...

and the

Tasman Sea The Tasman Sea 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 Abel Janszoon Tasman, who in 1642 wa ...

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 Port ...

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, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...

and western parts of the

Solomon Islands Solomon Islands, also known simply as the Solomons,John Prados, ''Islands of Destiny'', Dutton Caliber, 2012, p,20 and passim is an island country consisting of six major islands and over 1000 smaller islands in Melanesia, part of Oceania, t ...

. 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 ...