Cyclone predictions divided

The forecast for Monday at 7am from Victoria University's MetVuw weather website predicts the tail of a tropical storm will be right over Northland ... but other forecasters say the storm may not reach us. Image / Metvuw.com

Weather boffins are divided in their forecast on whether a severe tropical storm developing in the Pacific will unleash its fury on Northland early next week.

WeatherWatch modelling shows New Zealand is in the direct path of a tropical depression developing near Vanuatu, which could potentially make landfall early to mid next week.

Head weather analyst Philip Duncan said there was a large pool of low pressure north of New Zealand or Northland with conditions perfect for cyclone formation.

"While it was too early to lock in what might specifically happen in New Zealand, long-range models indicated northern regions had a moderate risk of being directly impacted. It's a bit tricky locking in the future track of a storm that is yet to even form, but latest data guidance suggests the centre of the low might cross the north east of the North Island - or perhaps just offshore from East Cape next Tuesday or Wednesday," he said.

Mr Duncan said weather analysts would have a better idea where the depression may head by the end of this week. He said the way cyclones formed meant the difference between fairly normal weather - and damaging cyclone weather - can be as little as a hundred kilometres and this made long range precise forecasts of severe weather very tricky.

MetService meteorologist Claire Flynn said it was difficult to predict the movement of a weather system that had yet to even form. But she did not rule out the possibility of the tropical storm heading towards Northland.

"One modelling indicates it will head this way but many other models are saying it won't," she said.

"There's a lot of uncertainty around its movement at this time."

Ms Flynn said rain was forecast for Northland early next week but it would not be heavy.

There were no thunderstorm warnings for the region at this stage, she said.

European weather models are predicting the new cyclone may weaken before reaching New Zealand while metvuw.com charts shows Northland will bear the brunt on Monday.

Fiji Meteorological Service is reporting a "high risk" of a cyclone forming by Thursday between Vanuatu and Fiji, which would then track southwards.

Forecasters would have a better idea in another 48 hours as to the likely track and intensity of the cyclone.