Drenching on way for upper North Island, cyclones being tracked

MetService says a tropical cyclone could potentially head towards New Zealand within the next week.

There are now two tropical cyclones in the South Pacific - Cyclone Maila in the Solomon Sea and Cyclone Vaianu to the east of Vanuatu.

MetService forecaster Louis Fernando said the Category 2 Cyclone Vaianu was gaining in speed and power.

"It is looking like it will intensify to a Category 3 either later today or into tomorrow."

"Some of the models are indicating that perhaps towards the weekend the remnants at least of the cyclone could affect parts of the North Island."

Cyclone Vaianu is currently tracking between Vanuatu and Fiji.

MetService had already issued an orange heavy rain warning for the Northland region from 10pm Monday till 4pm Tuesday as well as a strong wind watch starting 3am Tuesday.

Heavy rain watches are also in place for Auckland, the Coromandel and Bay of Plenty.

MetService meteorologist Alec Holden said while they were sure something was going to happen, there was still uncertainty as to which areas would be worst hit.

"The models have been quite jumpy. We've been getting a lot of different solutions of where the worst of the rainfall is going to be from run to run."

Northland is set to expect 90 to 120mm of rain, especially in the north and east.

The region experienced heavy rains and flooding at the end of March and some parts are still recovering from the deluge.

Holden said the country was currently "sandwiched between two competing systems".

"To the northwest of the country, we have this very broad area of low pressure that is attempting to move over the country and down south."

"However, blocking its path, or rather slowing it down significantly, we have a ridge of high pressure."

The result is a lot more showers and wet weather for the eastern seaboard of the country.

"Later today, and then through tomorrow and Wednesday, this broad low-pressure system that's been drawing this big feed of moisture from the subtropics is going to be trucking its way over the country."

Holden said this was the reason behind the warnings and watches being issued for the upper half of the North Island

He advised people in areas with watches and warnings to stay up to date with the latest forecast and keep an eye out for guidance from Civil Defence.