The 2022–23 South Pacific cyclone season was a below-average but very destructive tropical cyclone season that featured one of the costliest tropical cyclones in the Southern Hemisphere on record. The season officially started on November 1, 2022, and ended April 30, 2023; however, a tropical cyclone could form at any time between July 1, 2022, and June 30, 2023, and would count towards the season total. During the season, tropical cyclones were officially monitored by the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BOM) and New Zealand's MetService. The United States Armed Forces through the Joint Typhoon Warning Center (JTWC) also monitored the basin, issuing unofficial warnings for American interests. The FMS attaches a number and an F suffix to tropical disturbances that form in or move into the basin while the JTWC designates significant tropical cyclones with a number and a P suffix. The BoM, FMS and MetService all use the Australian Tropical Cyclone Intensity Scale and estimate windspeeds with a period of approximately ten minutes, while the JTWC estimates sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHWS). __TOC__

Seasonal forecasts Source/Record Region TropicalCyclones SevereTropicalCyclones RefsRecords Average (1969–70 – 2021–22): 160°E – 120°W 7 3 Record high: 160°E – 120°W 1997–98: 16 1982–83: 10 Record low: 160°E – 120°W 1990–91:  2 2008–09:  0 Predictions CWCL July 135°E – 120°W 6–9 CWCL August 135°E – 120°W 6–9 CWCL September 135°E – 120°W 7–10 CWCL October 135°E – 120°W 6–10 NIWA October 135°E – 120°W 6–10 3–4 FMS Whole 160°E – 120°W 5–7 1–4 FMS Western 160°E – 180° 3–6 1–3 FMS Eastern 180°   – 120°W 2–4 1–2

Ahead of the season officially starting on November 1, the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BoM), National Institute of Water and Atmospheric Research (NIWA) and the University of Newcastle's Australian Centre for Water, Climate and Land (ACWCL), each issued a tropical cyclone outlook that discussed the upcoming season. These outlooks took into account a variety of factors such as a persistent La Niña event and what had happened in previous seasons such as 1971–72, 1974–75, 1975–76, 1984–85, 2000–01, 2008–09, 2011–12 and 2017–18.

The first three of these outlooks were issued in July, August and September by the ACWCL, suggesting that it would be a near-normal season, with six to nine tropical cyclones occurring between 135°E and 120°W during the season. During October 2022, the ACWCL joined NIWA, BoM, MetService and various Pacific meteorological services with contributing towards the Southwest Pacific tropical cyclone outlook. This outlook suggested that between six and ten named tropical cyclones would occur between 135°E and 120°W, while three to four of these tropical cyclones were expected to intensify into either a Category 3, 4 or 5 severe tropical cyclone on the Australian tropical cyclone intensity scale.

In addition to contributing towards the Southwest Pacific tropical cyclone outlook, the FMS and the BoM issued their own seasonal forecasts for the South Pacific region. The BoM predicted that their self-defined western region had a 65% chance of seeing activity above its average of 4 tropical cyclones, while its self-defined eastern region had a 43% chance of seeing more than 6 tropical cyclones. Within their outlook the FMS predicted that between five and seven tropical cyclones would occur within the basin compared to an average of around 7. One these tropical cyclones was expected to intensify further and become either a Category 3, 4 or 5 severe tropical cyclone on the Australian tropical cyclone intensity scale. The FMS also predicted that the majority of systems would occur to the west of the International Dateline, with 3–6 tropical cyclones expected to occur between 160°E and 180° while 2–4 were expected to occur between 180° and 120°W.

Seasonal summary

Systems

Tropical Disturbance 01F

On December 10, the FMS reported that Tropical Disturbance 01F had developed, within an area of low vertical windshear near Fiji's southern Lau Islands. Moving southward under a moderate sheared environment with warm sea surface temperatures, 01F intensified into a tropical depression late on December 11, before being steered into a highly sheared environment due to an upper ridge to its north and an approaching upper trough from its west.

Tropical Disturbance 02F

Late on December 29, the FMS reported that Tropical Disturbance 02F had developed to the south of Vanuatu. The JTWC gave it a low chance for development due to the system having a fully obscured LLC and in a favorable environment of low wind shear, good poleward outflow and warm sea surface temperatures. At 3:00 UTC on December 30, the JTWC announced that the system had transitioned into a subtropical cyclone; however, the agency gave the system a low chance to develop into tropical cyclone due to persistent unfavorable environment. The system then moved into TCWC Wellington's area of responsibility on the next day, where it was reclassified as a non-tropical low.

Tropical Disturbance 03F

Late on January 5, the FMS reported that Tropical Disturbance 03F had formed near New Caledonia. The system generally moved southeast before the FMS ceased advisories on the system, on January 7. However, on January 8, the JTWC gave the system's chance for development, although in favorable environment, as low since it was in close proximity with Hale. But upon reanalysis, convection re-fired, and an eye feature was visible, although the JTWC later reported that the system had dissipated the following day.

Tropical Depression Hale

On January 7, Tropical Low 07U crossed into the basin from the Australian region, where it was reclassified as Tropical Depression 04F by the FMS. Later that day, the storm would feel the effects of moderate wind shear, with its convective structure splitting into two different regions, before it started to weaken as shear increased and its low-level center became elongated. The FMS issued their last advisory on Hale by the next day as it moved east-southeast towards the TCWC Wellington's area of responsibility, where they reclassified it as an extratropical low six hours later. The JTWC subsequently discontinued warnings on the system three hours later.

In preparation for Hale, MetService issued heavy rain and wind warnings for many parts of New Zealand. A state of emergency was later declared in the northeastern part of New Zealand as it approached the country. Hale caused widespread flooding and slips in northern and eastern parts of the country on January 10 and 11, particularly in the Coromandel and Gisborne areas. Washed away forestry slash clogged many rivers in the Gisborne region, exacerbating the flooding and accumulating around bridges downstream. Several metres of foreshore was eroded away by the storm surge in Whitianga, threatening waterfront buildings such as the Mercury Bay Boating Club. A child was killed on Waikanae Beach on January 25, two weeks after Hale impacted the country, after falling while playing on forestry slash debris left behind by the cyclone.

In real-time, the FMS assessed Hale peaking as a Category 1 tropical cyclone, however in their seasonal summary, the FMS would downgrade Hale to a tropical depression.

Tropical Cyclone Irene

By early January 13, the FMS noted that a low pressure system was expected to develop to the west of Vanuatu in the next 5 days, and gave it a moderate chance of development. However, the low formed in the Australian region late on the same day, and by January 14, it organized into a tropical disturbance, with the FMS designating it as 05F. 05F briefly entered the basin by the next day, before subsequently moving back to the Australian region late by the same day.

By January 17, 05F moved back into the South Pacific basin, where it was upgraded to a tropical depression by the FMS. At 03:00 UTC on January 18, the JTWC's began issuing warnings on the system, classifying it as Tropical Cyclone 09P. Alt URL The FMS subsequently followed suit, upgrading the system into a Category 1 tropical cyclone on the Australian scale and naming it Irene. At that time, satellite imagery showed Irene was quickly developing a central dense overcast (CDO). Under a favorable environment of warm sea surface temperatures, low wind shear and strong poleward outflow, Irene intensified into a Category 2 tropical cyclone late on the same day. However, as it moved over Tanna Island in Vanuatu, its weakly defined and elongated low-level circulation center quickly became exposed due to the wind shear, prompting the JTWC to issue its final warning on Irene and reclassify the system as a subtropical cyclone by January 19. The FMS subsequently downgraded Irene into a Category 1 tropical cyclone, and continued to issue warnings as it weakened while moving east-southeast, before declaring the system an extratropical cyclone late on the same day. Irene was last noted the next day.

A heavy rain alert was issued for some parts of Fiji and the public was advised to be on high alert. Similar warnings were also issued to Vanuatu. On January 19, Irene caused flooding and power cuts in Port Villa.

Tropical Depression 06F

On January 20, a tropical low entered the basin from the Australian region, where it was immediately designated as Tropical Depression 06F by the FMS. Later that day, the JTWC would recognize the system as a tropical cyclone, designating it as Tropical Cyclone 10P, although the system was becoming exposed due to a dry air infiltration. With the system becoming fully exposed due to increasing wind shear and large amounts of dry air, the JTWC would issue their final advisory on 06F the next day. The FMS continued to issue advisories on 06F as it continued east-southeast, before it turned south-southwest and degenerated into a low pressure area on January 22. The remnants of the system impacted New Zealand on January 27, causing severe flooding which killed 4 people and resulted in US$1.2 billion in damages.

Severe Tropical Cyclone Gabrielle

On February 10, Severe Tropical Cyclone Gabrielle moved into the basin from the Australian region, as a Category 3 severe tropical cyclone on the Australian scale. Gabrielle began to experience an increase in northwesterly vertical wind shear, the JTWC downgraded it to a Category 1-equivalent cyclone. Later that day, Gabrielle moved into MetService's area of responsibility. By 21:00 UTC, the low-level circulation became fully exposed on the central convection, the JTWC discontinued warnings on the system. Alt URL Later the next day, Gabrielle was downgraded to a Category 2 tropical cyclone by the MetService. Gabrielle subsequently passed directly over Norfolk Island. The BoM and MetService reported that Gabrielle had transitioned into a deep subtropical low later that day. The JTWC classified it as a subtropical storm.

Weather warnings were issued across Norfolk Island and New Zealand, with multiple states of emergency being declared in New Zealand as the cyclone impacted the country. Heavy rain and strong winds led to widespread power outages and flooding across the upper North Island, with a national state of emergency being declared on February 14. Two people were killed in Muriwai, while eight others were killed in Hawke's Bay, and one person killed in Gisborne. New Zealand declared a national state of emergency for the third time in its history on February 14 as Cyclone Gabrielle caused widespread flooding, landslides and huge ocean swells.

Severe Tropical Cyclone Judy