The 2023–24 Australian region cyclone season was the fifth and final consecutive season to have below-average activity in terms of named storms, with only eight named storms developing. Despite this, it produced six severe tropical cyclones, becoming the second season in a row to have at least five severe tropical cyclones. The season officially started on 1 November 2023 and ended on 30 April 2024. However, tropical cyclone formation is possible at any time of the year, as shown by the formation of Tropical Low 16U in May.

The season commenced on 4 December with the development of Cyclone Jasper. Jasper peaked as a category 5 severe tropical cyclone a few days later, eventually making landfall on the Cape York Peninsula of Queensland in a weakened state. The system caused torrential rainfall in northern Queensland, becoming Australia's wettest tropical cyclone on record. After almost a month of inactivity, Cyclones Anggrek and Kirrily developed in short succession in mid-January. Anggrek meandered in the open Indian Ocean, eventually entering the South-West Indian Ocean. Kirrily slowly organised before finally striking the Queensland coast as a category 3 cyclone on 25 January. Lincoln was first noted in the Gulf of Carpentaria on 14 January, intensifying into a cyclone two days later. Making landfall near the Northern Territory-Queensland border, Lincoln later emerged over the Indian Ocean but failed to reintensify into a tropical cyclone.

The tropical low that would become Cyclone Neville was first noted on 4 March, but the system was not upgraded to a tropical cyclone until 20 March. After being named, Neville rapidly intensified into a category 4 severe tropical cyclone. Megan developed on 13 March, becoming a category 4 in the Gulf of Carpentaria before making landfall. Olga formed on 4 April and rapidly deepened into a category 5 storm three days later, the second of the season. The last named storm of the season, Cyclone Paul, developed shortly after Olga, and peaked as a category 2. Collectively, the systems during this season caused $790 million (2023 USD) in damage, mainly due to Jasper, along with 1 fatality, also caused by Jasper. __TOC__

Season forecasts Source/Record TropicalCyclone SevereTropical Cyclone RefRecord high: 21 12 Record low: 3 0 Average (1969–70 – 2023–24): 11 Region Chanceof less Averagenumber Ref Whole (90°E–160°E)80%11 Western (90°E–125°E)72%7 North-Western (105°E–130°E)75%5 Northern (125°E–142.5°E)61%3 Eastern (142.5°E–160°E)76%4 Western South Pacific (142.5°E—165°E)68%4 Eastern South Pacific (165°E—120°W)40%6

Ahead of the season officially starting on 1 November, the Australian Bureau of Meteorology (BoM) and New Zealand's National Institute of Water and Atmospheric Research (NIWA) both issued a tropical cyclone outlook that discussed the upcoming season. These outlooks took into account a variety of factors such as a developing El Niño event and what had happened in previous seasons such as 1972–73, 1982–83, 1997–98, 2009–10 and 2015–16. Within their seasonal outlook for the Australian region, the BoM suggested that there was an 80% chance, that the whole region between 90°E – 160°E, would be below average, having less than the long term average of 11 tropical cyclones. They also suggested that each of their self-defined Western, Northern, North-western and Eastern regions would see a below-average amount of tropical cyclone activity.

The BoM also issued a seasonal forecast that discussed tropical cyclone activity over the South Pacific Ocean for their self-defined eastern and western regions of the South Pacific Ocean. Within this forecast, they predicted that their western region between 142.5°E and 165°E would have a below average amount of activity, while their eastern region between 165°E and 120°W had a 60% chance of seeing activity above its average of 6 tropical cyclones. Along with other Pacific Meteorological Services, the BoM contributed to NIWA's Southwest Pacific tropical cyclone outlook, which predicted that nine and fourteen tropical cyclones would occur between 135°E and 120°W. At least four to eight of these systems were expected to intensify further and become either a Category 3, 4 or 5 severe tropical cyclone on the Australian tropical cyclone intensity scale.

Season summary

Early activity The season officially started on 1 November, however the first system, Cyclone Jasper, would not be active until 4 December, when it crossed into the basin as a tropical low from the South Pacific. The low became a named storm on 5 December, receiving the name Jasper, and intensified into the season's first severe tropical cyclone the next day. Jasper made landfall in Far North Queensland as a Category 2 tropical cyclone on 13 December.

Season starts After a significant lull in activity, Tropical Cyclone Anggrek and Tropical Low 03U formed on 10 and 11 January respectively, with the latter dissipating on 23 January. The next day, Cyclone Kirrily formed. Tropical Low 06U formed on 30 January, dancing out of basin the next day and waltzing back in on 5 February. Tropical Cyclone Lincoln formed on 16 February and made landfall on the Gulf of Carpentaria coast. Severe Tropical Cyclone Neville formed north of the Cocos Islands on 1 March and left the basin 20 days later. Severe Tropical Cyclone Megan formed on 13 March from a tropical low over the coast of the Gulf of Carpentaria. Short-lived Tropical Low 10U formed and weakened within the same day of 14 March. Severe Tropical Cyclone Olga formed within a monsoon trough south of Sumba Alt URL on 4 April. Tropical Cyclone Paul formed 5 days later over the Louisiade Archipelago. Tropical Low 12U formed on 12 April and remained traceable.

Off-season The season ended with Tropical Low 16U, which formed on 4 May and weakened the next day.

Systems Severe Tropical Cyclone Jasper

On 2 December, the Australian Bureau of Meteorology (BoM) reported that Tropical Disturbance 03F, which was re-designated as Tropical Low 02U, had formed in the South Pacific Ocean in Fiji's area of responsibility. Two days later, on 00:00 UTC of 4 December, the system would enter the Australian area of responsibility. The Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert (TCFA) later that day, projecting a high likelihood of a significant tropical cyclone developing. Alt URL Later the next day, the JTWC subsequently initiated advisories on the system and classified it as Tropical Cyclone 03P. Alt URL The BoM subsequently followed suit and upgraded it to a Category 1 tropical cyclone, naming it Jasper. Jasper started to track southward under the steering influence of a near equatorial ridge to the east. During the next day, the cyclone's centre continued to organise, with deep convective bands starting to wrap around the centre, prompting the JTWC to upgrade the system to a Category 1 hurricane. Alt URL Jasper rapidly intensified into a Category 3 severe tropical cyclone, due to being in an environment with warm sea surface temperatures and low wind shear. The next day, it further intensified, becoming a Category 5 severe tropical cyclone. Operationally, the BoM classified Jasper as a high-end Category 4 severe tropical cyclone with winds of , but during post-cyclone reanalysis concluded a peak wind speed of based on Synthetic-aperture radar measurements. Shortly thereafter, Jasper began weakening, with its eye becoming cloud-filled and the deep convection eroding due to dry air entrainment. Alt URL Jasper would reintensify, and at 12:00 UTC on 13 December, made landfall as a Category 2 tropical cyclone in Wujal Wujal, Queensland."Cyclone Jasper makes landfall in Australia ". AFP. 13 December 2023. After making landfall, the JTWC discontinue warnings on the system later that day. Alt URL By 14:00 UTC that day, the BoM reported that Jasper had weakened to a tropical low. However, Jasper remained traceable, and the BoM would give the tropical low a moderate chance of redeveloping into a tropical cyclone on 15 December. However, they would soon downgrade its chances of re-developing into a very low as the storm turned southeast further inland, causing the tropical low to rapidly weaken, and on 18 December, Jasper was last noted over the Cape York Peninsula.

Jasper produced torrential rainfall, peaking at at Bairds near the Daintree River, making the wettest tropical cyclone in Australian history, beating the previous record of Cyclone Peter in 1979. The Insurance Council of Australia estimated that Jasper caused AU$1 billion (US$670 million) in damages.

Severe Tropical Cyclone Anggrek

On 9 January, the BoM noted that a tropical low could form in the Indian Ocean, designating it as 04U. Later the next day, the BoM reported that it had formed to the northwest of the Cocos Islands. On 11 January, the JTWC followed suit in monitoring the system, after convection had significantly consolidated around the circulation. Three days later, the agency issued a TCFA, for the disturbance as it was situated in an environment of warm waters, low shear, and good outflow. By 15 January, the JTWC began issuing advisories, recognising it as Tropical Cyclone 06S after its circulation had improved, with the BoM subsequently followed suit and upgraded it to a Category 1 tropical cyclone. Since the cyclone was within their area of responsibility, Meteorology, Climatology, and Geophysical Agency (BMKG) named the system Anggrek. It tracked southeast before changing direction and tracking west. Anggrek remained nearly stationary due to weak steering ridges to the north and southwest, the system generated upwelling, causing sea surface temperatures to decrease. Despite that, Anggrek steadily re-intensified, and after entering favourable conditions on 24 January, became a Category 3 severe tropical cyclone, with estimated maximum 10-minute sustained winds of , and a central barometric pressure of . Alt URL while the system's depiction showed that tightly circulating around a ragged eye. The next day, the system exited the basin towards the South West Indian Ocean.

Tropical Low 03U

On 7 January, the BoM noted the possibility of a tropical low forming near the north Kimberley, as a monsoon trough was expected to develop along the Top End. It was predesignated as 03U. This came to fruition 4 days later, when the BoM reported that it was developing over the southern Joseph Bonaparte Gulf within the trough. As the tropical low tracked overland, the system maintained a robust outflow channel in the upper troposphere. The BoM continued to monitor the low as it moved slowly southeast, then turning west towards Western Australia by 20 January, until they determined that it would not develop into a tropical cyclone on 23 January.

The low and its associated monsoon brought heavy rainfall to the Northern Territory, resulting in the BoM issuing flood watches and warnings throughout the Top End and central Northern Territory. Wadeye received of rainfall.

Severe Tropical Cyclone Kirrily