Large swells likely as Cyclone Atu brushes past

Wilma left a trail of destruction in the Far North. Photo / Supplied

The latest cyclone to grow out of the Pacific is forecast to brush past New Zealand, creating a risk of high seas on the North Island's east coast.

Cyclone Atu formed on Saturday, true to its name ("Saturday-born"), and is expected to reach New Zealand waters by Wednesday.

Atu is now a category two storm moving southwest from Vanuatu at a speed of 8km/h. The Fiji Meteorological Service has predicted it could turn into a category three cyclone, with winds of around 120km/h.

WeatherWatch analyst Philip Duncan said the storm followed a similar pattern to Wilma, and could yet mimic that huge cyclone.

"The sea temperatures are favourable, the atmosphere is favourable and Atu will cross the same body of water that saw Wilma go from a category 2 storm to a category 4 storm back on Auckland Anniversary weekend."

There is only a 20 per cent chance of the cyclone hitting New Zealand directly but a close miss could still have some impact.

"We're very lucky, it's going to be incredibly close, but not quite close enough," said Mr Duncan.

The Joint Typhoon Warning Centre had revised the cyclone's path to closer to New Zealand but the weather system was unlikely to cause serious damage on our coastline.

The greatest threat was from raised sea levels anywhere between Northland and the East Cape. Mr Duncan warned that Atu could create large swells and coastal erosion in Gisborne and Hawkes Bay, the most exposed spots.

The cyclone's arrival in New Zealand waters will also coincide with a 3.5m tide in Auckland and a 3m tide in Coromandel.

Mr Duncan said: "This is the third cyclone to pass us to the east. When we've seen what they've done to Australia, New Zealand has been lucky to be on the outskirts of where they've hit."

Tropical cyclones lose a lot of energy when entering New Zealand waters because our oceans are too cold to fuel them.

After a blisteringly hot start to February, which put New Zealand on track for its hottest ever month, the last week was slightly colder. The first signs of autumn were beginning to show, with cooler mornings as a result of longer nights, which give the warm air more time to cool down.

MetService forecaster Rob Kerr said Auckland would be around 25C today and tomorrow, before falling to 22C on Wednesday and Thursday.

The North Island will see rain tomorrow evening, Wednesday morning, and a few showers on Friday.

CYCLONE SEASON
Storms since December.

Rated category 3 and above:

* Vania, Category 3

* Zelia, Category 3

* Wilma, Category 4

* Yasi, Category 5

* Bianca, Category 4

Storms still active:

* Dianne, Category 3

* Carlos, Category 1, NT

* Atu, Category 2, New Caledonia, Vanuatu