Overview
Cyclone Vaianu is approaching New Zealand and will be the dominant weather feature this weekend. The system is expected to pass just northeast of Northland by late Saturday before tracking south across the North Island on Sunday. The cyclone brings a combination of damaging winds, heavy rain, and coastal inundation, and MetService has described it as a multi-hazard, potentially life-threatening event. All mariners are strongly advised to seek safe harbour before conditions deteriorate and to monitor MetService for updates, which will be issued through the weekend as the track becomes clearer.
Friday (today)
Conditions are manageable for now but deteriorating. A ridge of high pressure is keeping central New Zealand relatively settled, but the outer circulation of Vaianu is already generating increasing southeast winds and building swells across the upper North Island. The Brett area is seeing southeast 20 knots rising to 30 knots this evening, with a northeast swell building to 4 metres. Kaipara is southeast 25 knots with a rough sea and a northeast swell reaching 4 metres north of Cape Reinga. The Hauraki Gulf is seeing southeast 15 knots rising to 20 knots, gusting to 30 late evening. Conditions further south remain relatively light, with most South Island areas sitting at variable 10 to 15 knots and slight to moderate seas.
Saturday
Conditions will deteriorate sharply across the north. This is not a day to be at sea anywhere north of the Bay of Plenty.
A storm warning is in force for the Brett area, where southeast winds will build to 50 knots by evening, and the sea will become high, with a long-period easterly swell reaching 8 metres. Colville carries the same storm warning, with identical conditions expected. Kaipara is on a gale warning, with southeast winds reaching 35 knots and an easterly swell rising to 6 metres north of Cape Reinga.
The Hauraki Gulf is on a gale warning, with southeast winds to 35 knots, gusting to 45 by late evening and a very rough sea. The Bay of Islands is also under a gale warning, with winds to 45 knots gusting 55 knots by early evening and an easterly swell rising to 6 metres. Bream Head to Cape Colville and the Coromandel are both under strong wind advisories building to gale warning conditions by evening, with swells to 4.5 metres.
The Plenty area is on a gale warning, with easterly winds reaching 40 knots by evening and a northeast swell building to 6 metres offshore. Portland is also under a gale warning, with conditions roughest north of East Cape. Milford and Puysegur are both on gale and storm warnings, respectively, driven by the front approaching Fiordland from the west rather than Vaianu directly.
The Waitemata Harbour is under a strong wind advisory for Saturday, with southeast 25 knots gusting 35 in the morning.
Heavy swell warnings are current for the Wellington south coast, the Kapiti-Porirua coast, and the Wairarapa coast.
Sunday
The worst of the cyclone’s effects are expected Sunday as Vaianu moves south across the North Island. Land-based severe weather warnings at this stage include a red wind warning for the Coromandel Peninsula and Great Barrier Island, with gusts to 140 km/h. Orange wind warnings cover Northland, Auckland, Bay of Plenty, Gisborne, Hawke’s Bay, Waikato, Taranaki, and Whanganui. Heavy rain warnings and watches are in force across most of the North Island and parts of the upper South Island.
Marine conditions on Sunday will be extreme across all northern and eastern areas. No recreational or coastal boating should be undertaken.
Advice
Any vessel currently at sea or in an exposed anchorage in the upper or eastern North Island should make for safe harbour immediately. Saturday will be too late for many harbours to enter safely. Skippers should check their berth lines, secure loose gear, and monitor MetService for updates, with the next forecast revision due 9pm Friday. The cyclone’s track carries uncertainty, and warnings are likely to be upgraded as it approaches.
Sources: MetService Severe Weather Warnings (issued 9:51am Fri 10 Apr), MetService Marine Warnings and Coastal Weather Forecasts (issued from 11:06am to 1:25pm Fri 10 Apr).
