Tropical Cyclone Vaianu Strengthens as It Tracks Toward New Zealand

MetService is closely monitoring Tropical Cyclone Vaianu, a Category 2 system currently east of Vanuatu that is gaining strength and speed as it moves through the South Pacific on a track that could bring it directly toward the upper North Island by the weekend.

The cyclone is one of two weather systems causing concern for forecasters this week. A separate subtropical low approaching from the Tasman Sea is already delivering heavy rain to Northland, with an orange-level heavy rain warning in place for the region. Between 90 and 120 millimetres of rain is expected in northern and eastern areas of Northland, with strong easterly gales also forecast.

But it is Cyclone Vaianu that has forecasters most worried. The system is currently sitting about 600 kilometres northwest of Nadi in Fiji, with winds near the centre exceeding 150 kilometres per hour, making it a Category 3 tropical cyclone. 1News reported that the cyclone is strengthening, and while its exact path is still uncertain, current modelling shows it tracking southeastward toward New Zealand’s North Island.

MetService has warned that Vaianu is forecast to move toward the top of the North Island, potentially making a direct impact on Northland and Auckland this weekend. The heaviest rain is expected across the north and east of the North Island, although the areas affected and the intensity of those impacts will depend heavily on the path the cyclone takes as it approaches.

The timing is particularly bad. New Zealanders are returning home from Easter holidays, many driving long distances on already-stressed motorways. A cyclone arriving on Sunday could create dangerous driving conditions across much of the North Island, with heavy rain, strong winds, and large swells all expected.

For Northland, the situation is compounded by the subtropical low that is already bringing significant rainfall. MetService had initially issued an 18-hour heavy rain watch for the region before upgrading it to an orange warning. East to northeast gales are expected ahead of the low, which is forecast to move slowly southward, reaching the upper South Island by Tuesday evening. The wettest conditions from this system are expected through Wednesday before it clears eastward on Thursday.

The potential for Cyclone Vaianu to arrive on the heels of this subtropical low means the ground could already be saturated in many areas, increasing the risk of flooding, slips, and surface flooding on roads. The NZ Herald reported that the combination of the two systems could bring a prolonged period of wet and windy weather to much of the country.

MetService is urging New Zealanders to keep up to date with the latest forecasts and warnings, particularly anyone in Northland, Auckland, the Coromandel Peninsula, and western Tasman. Forecasters say it is too early to lock in a definite path for Vaianu, but the current trajectory puts the North Island squarely in its sights.

New Zealand has been hit by several destructive cyclone events in recent years, including Cyclone Gabrielle in February 2023, which caused widespread devastation across the east coast of the North Island. While Vaianu is not yet expected to reach the same intensity by the time it arrives, the memory of that event remains fresh for many communities still rebuilding.

Are you preparing for the storm? Let us know in the comments what conditions are like in your part of the country.