Tonga could face heightened cyclone risks in the coming months as a La Niña weather pattern remains in effect, forecasters warned.
The season’s first cyclone, Pita, passed by Tonga over the weekend, marking an early warning for the South Pacific’s most active cyclone period, which typically intensifies from January.
La Niña refers to the cooling of ocean surface temperatures in the tropical Pacific, particularly near and east of the international date line. This weather pattern often disrupts global climate systems, leading to more tropical cyclones and heavier rainfall in some regions while causing drought in others.
“La Niña means different things for different people,” said NIWA forecaster Chris Brandolino. He noted that areas near the Coral Sea, including Tonga, Vanuatu, and the Solomon Islands, could experience more tropical cyclones due to La Niña’s influence.
Rainfall is also expected to increase in regions near the Coral Sea. However, areas further east, such as French Polynesia and the Cook Islands, may experience drier conditions as cooler ocean temperatures suppress rainfall.
“These cool ocean temperatures, they don’t encourage rainfall – they favour dryness,” Brandolino explained.
Tonga and neighbouring Pacific nations are also bracing for stronger trade winds, particularly in areas just west of the international date line.
“People may notice fast or stronger trade winds and maybe higher waves,” Brandolino added, describing potential impacts near Fiji and New Caledonia.
The South Pacific cyclone season, which runs until April, poses ongoing challenges for the Pacific island nations, with preparedness critical to minimizing risks.