Australian region tropical cyclone

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 eastern Southern Indian Ocean or the far western South Pacific Ocean. 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 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 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 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, Darwin and Brisbane 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. 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 As of 2025, The Bureau of Meteorology has discontinued tropical cyclone seasonal outlooks, as season modelling is no longer accurate as a result of climate change.

The Bureau of Meteorology 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 Indian Ocean including the Cocos (Keeling) Islands and Christmas Island, and waters off Western Australia west of Kuri Bay. The region also covers waters off Indonesia that include the main islands of Java, Bali, Lombok, Sumbawa, Sumba, Flores and the western half of Timor. 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 Arafura Sea 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 and includes the Coral Sea and the Tasman Sea. Lord Howe Island 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 and western parts of the Solomon Islands. 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.

Climatology Tropical cyclones typically occur during the tropical cyclone season, though they can occur at any time in the year. The basin has an average of 10 tropical cyclones each season, with 3-4 landfalls. The amount of cyclones in the basin is heavily influenced by the El Niño and other climate drivers, with the Queensland coast recording 3-4 times as many cyclones during La Niña years as opposed to El Niño years. Activity in the region is also enhanced by a positive Indian Ocean dipole, and less active when it is in a negative phase.

The Australian region is subdivided into three smaller basins. The Eastern basin extends from 142.5-160°E, and averages three cyclones per season. The Central basin (Northern region) spans 125-142.5°E, averaging two cyclones each season, and the Western basin spans 90-125°E and records an average of six cyclones per season.Tropical cyclones and climate change in Australia – Earth Systems and Climate Change Hub

Seasons +Historical storm formation by month between 1990 and 2020 Before 1900

1900–1909

1910–1919

1920–1929

1930–1939

1940–1949

1950–1959

1960–1969

Season Strongeststorm Deaths Damage Retired names Notes 1960–61 1961–62 1962–63 1963–64 Audrey 1964–65 Flora 1965–66 1966–67 Dinah 1967–68 1968–69 15 13 1 Amber 1969–70 14 14 1 Ada 14 ? Ada

1970s Season Strongeststorm Deaths Damage Retired names Notes 1970–71 20 20 10 Sheila-Sophie Unknown ? Dora Fiona-Gertie 1971–72 18 18 10 Emily Unknown ? Althea Daisy Emily 1972–73 15 15 8 "Flores" >1,574 ? Madge Deadliest Australian Region cyclone season ever recorded. Features the "Flores" cyclone. The deadliest cyclone recorded in the Southern Hemisphere 1973–74 19 19 9 Pam Unknown ? Wanda 1974–75 16 16 7 Trixie >71 ? Tracy Trixie 1975–76 16 15 8 Joan Unknown ? Joan David Beth 1976–77 13 13 6 Ted Unknown ? Ted 1977–78 9 5 2 Alby Unknown ? Alby 1978–79 13 12 5 Hazel Unknown ? 1979–80 15 15 9 Amy Unknown ? Simon

1980s Season Strongeststorm Deaths Damage Retired Names Notes 1980–81 14 14 11 Mabel Unknown Unknown Cliff 1981–82 15 15 7 Bernie Unknown Unknown 1982–83 7 7 5 Elinor Unknown Unknown Jane Elinor 1983–84 22 21 11 Kathy 1 $19 million Kathy Lance 1984–85 20 18 11 Kristy 0 $3.5 million Nigel Sandy Margot 1985–86 17 16 8 Victor 153 $250 million Winifred Manu 1986–87 9 7 2 Elsie 0 None Connie Jason Elsie 1987–88 6 5 2 Gwenda-Ezenina 1 $17.9 million Agi Charlie Herbie 1988–89 14 13 6 Orson 6 $93.9 million Ilona Delilah Ned Aivu Orson 1989–90 14 14 4 Alex Unknown Unknown Pedro Felicity Tina Ivor

1990s Season Strongeststorm Deaths Damage Retired names Notes 1990–91 12 10 7 Marian 27 Joy Daphne Fifi 1991–92 12 10 9 Graham 5 Mark Ian 1992–93 8 8 4 Oliver 0 Nina Lena Oliver Roger Adel 1993–94 14 12 7 Theodore 22 Naomi Pearl Quenton Theodore Sharon 1994–95 19 6 6 Chloe 1 Annette Bobby Violet Warren Chloe Agnes 1995–96 19 15 9 Olivia 1 Frank Gertie Barry Celeste Ethel Kirsty Olivia 1996–97 17 15 5 Pancho 34 Lindsay Fergus Rachel Justin Rhonda 1997–98 11 9 4 Tiffany Sid Katrina Alt URL 1998–99 21 14 9 Gwenda 8 Thelma Rona Vance Elaine Gwenda Features Gwenda, tied with Inigo as most intense cyclone recorded in the basin. 1999-00 14 12 5 Paul 0 John Steve Tessi Rosita TotalsGwenda≥

2000s Season Strongeststorm Deaths Damage Retired names Notes 2000–01 14 8 3 Sam 2 Sam Abigail 2001–02 14 10 3 Chris 19 Upia Chris 2002–03 11 9 3 Inigo 62 Erica Graham Inigo Epi Features Inigo, tied with Gwenda as most intense cyclone recorded in the basin. 2003–04 13 10 5 Fay 0 Monty Fay 2004–05 13 10 5 Ingrid 5 Harvey Ingrid 2005–06 18 12 8 Glenda 0 Clare Larry Glenda Monica Features Monica, most intense cyclone ever recorded in the basin in terms of sustained winds. 2006–07 8 5 3 George 3 George 2007–08 14 10 3 Pancho 149 Guba Helen Durga 2008–09 24 10 3 Hamish 5 Dominic Hamish 2009–10 13 8 4 Laurence 3 Laurence Magda TotalsInigo≥

2010s Season Strongeststorm Deaths Damage Retired names Notes 2010–11 28 11 6 Yasi 3 Tasha Carlos 2011–12 21 7 3 Lua 16 > Heidi Jasmine Lua 2012–13 16 9 6 Narelle 20 Oswald Rusty 2013–14 17 10 5 Ita 22 Christine Ita 2014–15 18 9 7 Marcia 1 > Lam Marcia Olwyn Quang 2015–16 11 3 0 Stan 0 None None 2016–17 30 9 3 Ernie 16 Debbie Second costliest season on record. 2017–18 23 11 3 Marcus 41 Marcus 2018–19 25 11 5 Veronica 14 Trevor Veronica 2019–20 19 9 3 Ferdinand 28 $4.3 million Damien Harold Mangga TotalsMarcus≥

2020s Season Strongeststorm Deaths Damage Retired names Notes 2020–21 27 8 3 Niran 272 $701 million Seroja Second-deadliest Australian region cyclone season on record. 2021–22 32 10 2 Vernon 4 $80 million Seth 2022–23 25 7 5 Darian Ilsa 8 $225 million Freddy Gabrielle Ilsa 2023–24 11 8 6 Jasper 1 $790 million Jasper Kirrily Megan Features Jasper, the wettest tropical cyclone in Australia's history. 2024–25 24 12 8 Zelia 52 >$1.913 billion Zelia Alfred First above-average season in the Australian region since 2005–06. 2025–26 24 11 7 Maila 26+ $610 million Maila The most active start to the season in the Australian region since 1983–84.Includes the first storm in 19 years to be named by TCWC Port Moresby since Guba in 2007 and also the most powerful tropical cyclone in TCWC Port Moresby‘s area of responsibility, Maila.Driven by a record-breaking negative Indian Ocean Dipole (IOD), which hit a weekly low of -1.94°C in November. Totals 119 44 24 Darian and Ilsa 338 $3.769 billion 11 names

Australian region tropical cyclone

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