A tropical cyclone forming in the Pacific is looking less likely to make a direct hit on New Zealand early next week, but dangerous beach conditions can be expected on the eastern coasts of the North Island, WeatherWatch head weather analyst Philip Duncan says.
Swells up to three or four metres high could pound the coastlines of the upper North Island in Northland, Coromandel Peninsula, Bay of Plenty, Gisborne and Hawke's Bay on Monday and Tuesday, Mr Duncan said.
Two lows north of New Zealand appear to be becoming cyclones, with one -- between Vanuatu and Fiji -- looking likely to become a severe storm. The second, smaller low could slide behind the larger low, he said.
"The centre of what we've dubbed Low 1, directly north of NZ will likely come within 800 kilometres of northern New Zealand, based on various models today and bring very dangerous beach conditions. Low 2 may move into the upper North Island with heavy rain at the same time, making it feel like one system bringing rough seas and tropical downpours.
"There's a chance we may just get some humidity, wind and downpours rather than severe weather ... it will depend on the size of the high to the east of the North Island, as it will directly affect how much wet weather can move into New Zealand and how much gets blocked from tracking southwards towards us."
The larger low was turning into a tropical storm this morning, which meant it would probably be given a name today. Because it is in Fiji's area of responsibility, authorities in that nation will name it. Winston is the next name on their list, Mr Duncan said.
He expected the low would form a tropical cyclone in the next day or two.
American models yesterday showed the weather system was likely to strike the North Island on Monday and Tuesday next week, but this morning the chance of a direct hit had been reduced to 40 per cent, he said.
But that was no reason for complacency.
"The big message is while there's complete uncertainty whether the centre of the low will hit New Zealand directly, there's not much of a question that it will bring down dangerous beach conditions for the North Island."
Traditionally, ex-tropical cyclones that reached New Zealand took lives on the water or at the beach, rather than on land, Mr Duncan said.
Meanwhile, Civil Defence Waikato have taken a fun approach to informing Facebook followers of the situation.
They've launched a competition to name the cyclone.
"It's not a cyclone yet, and hopefully it doesn't become one. If it does, what name would you like it to have? Cyclone Sharon? Cyclone Garry? Tell us what you want it to be called and you could win one of three 'Calm Your Farm' mugs!," they wrote.
More than 130 names had been suggested by 8.45am, many from parents, such as Katy Poucher.
She wrote: "Cyclone Anneliys, she's a 5 yr old with three big bros she runs rings a around ... till she runs out of puff. I NEED a calm your farm mug..."
Mr Duncan said the competition was a great way to alert people in a fun way.
"I love it."