Good guidance on the number of severe tropical cyclones, despite a lower overall number of tropical cyclones

25 April 2023, Apia – A review of the tropical cyclones (TC) that developed in the Pacific during the 2022-2023 southwest Pacific TC season revealed the fewest number of named TC since the 2016-2017 season.
 
The review was presented by Mr Ben Noll of the National Institute of Water and Atmospheric Research (NIWA) during the 12th Pacific Islands Climate Outlook Forum (PICOF-12) which took place last week.

The PICOF is a gathering of Pacific National Meteorological and Hydrological Services (NMHSs) and partners which occurs in April and October of every year, providing reviews of the state of the ocean and climate in the Pacific for the past six months, and projections for the next six. It is hosted by the Secretariat of the Pacific Regional Environment Programme (SPREP) through the Pacific Meteorological Desk Partnership. 

A total of five named cyclones developed in the Pacific during the 2022-2023 TC season. Of the five, three cyclones were categorised as severe TC. This was consistent with the 2022-2023 season predictions by the Bureau of Meteorology, Fiji Meteorological Service, and NIWA presented during PICOF-11.

In explaining why there was a low number of TC, Mr Ben Noll of NIWA said that very unusually warm seas towards to sub-tropics may have affected stability profiles across the region, leading to fewer tropical cyclones. 
“However, even in a year with fewer tropical cyclones, we still saw considerable damage from the three severe tropical cyclones,” Mr Noll said. 

TC Hale was the first to occur in early January 2023, followed by TC Irene in the same month. The first severe cyclone, TC Gabrielle occurred in February, impacting the North Island of New Zealand, resulting in extreme rainfall and flooding in most places. 

Vanuatu was the hardest hit this season, with TC Judy and TC Kevin, both Category 4 severe TC, striking the country within 48 hours of each other. TC Judy first made landfall on 1 March with TC Kevin following closely on 3 March. The country was also hit by TC Irene in January.

The Government of Vanuatu reported that more than 200,000 people were affected by TC Judy and TC Kevin, with damages to people’s homes and livelihoods, as well as infrastructure.

With the northern Pacific now entering its tropical cyclone season, and with the current El Niño-Southern Oscillation (ENSO) showing signs of an El Niño developing later this year, the public is urged to remain vigilant at all times and take heed of advice and warnings from their national meteorological service.  

The PICOFs are organised through a collaborative partnership between SPREP and the World Meteorological Organization, with technical support provided by the Australian Bureau of Meteorology, National Institute of Water and Atmospheric Research, Commonwealth Scientific and Industrial Research Organisation, the Pacific Community, Meteo-France, and the National Oceanic and Atmospheric Administration, together with the Pacific Islands Climate Services Panel for the Pacific Meteorological Council.

For more information, please contact Mr Philip Malsale at [email protected].