MetService's rain forecast as of Sunday 1am. Photo: Supplied / MetService
Heavy rain from Cyclone Gabrielle is likely to start arriving in Northland overnight, while people in the Coromandel in areas at risk are being warned to self evacuate.
A red warning for heavy rain is in place for the Coromandel Peninsula from 3am Sunday and Tairāwhiti Gisborne north of Tolaga Bay from 3pm Sunday.
An orange warning is in place for heavy rain for several areas including Auckland north of Whangaparaoa and Great Barrier Island from 3am Sunday and Northland from 9pm Saturday.
The most recent updates from MetService can be found on their warnings page throughout the evening.
Moderate rain is falling over much of Northland as of 9pm.
An orange warning for strong winds has been made for Coromandel from 3pm Sunday, Auckland from Whangaparoa south from 4pm Sunday and Northland and Auckland from Whangaparoa north from 7am Sunday.
MetService says regardless of the storm's eventual track, there is a very high risk of extreme and impactful weather over the upper North Island late tonight spreading to south and central New Zealand by Monday.
Heavy rain warnings and watches are also in place for Hawke's Bay, Bay of Plenty, eastern Taupō and Wairarapa starting Monday.
The cyclone has been downgraded to Category 2 from Category 3, with wind speeds estimated between 89-118 km/h.
Civil Defence Controller for the Coromandel Garry Towler said after weeks of severe weather, civil defence officials are very worried.
Civil Defence is recommending that residents in the Coromandel consider evacuating before Sunday evening if they live in an at-risk area.
"Things have changed a little bit and we are now confident to say that a very severe and possible destructive cyclone is descending on the Coromandel," Towler said in a video.
"We ask people to seriously consider preparing to evacuate if you are in areas that are prone to flooding or areas that are possibly going to be inundated with coastal surge."
"We need you to take this seriously."
MetService says regardless of the storm's eventual track, there is a very high risk of extreme and impactful weather over the upper North Island late Saturday night, spreading to south and central New Zealand by Monday.
MetService says it expects up to 400 millimetres of rain to fall in the regions, mostly on Monday.
"Central Auckland is still under a Severe Weather Watch. It hasn't been upgraded due to the uncertainty of movement of the cyclone, but it could be in the near future, " MetService's head of weather communication Lisa Murray said.
"Auckland is already sodden from recent events which could exacerbate impacts of any strong wind and rain."
Norfolk Island in firing line first
North of New Zealand, cyclonic winds have cut power, brought down trees and blocked roads on Norfolk Island, with residents urged to take shelter as Tropical Cyclone Gabrielle tracks towards the island.
The Bureau of Meteorology says gale-force winds could impact the island through Saturday night and into Sunday.
In an update on Saturday afternoon, the Bureau said conditions on the island were deteriorating as the cyclone approached, with the cyclone expected to pass very near, or over the island this evening.
Emergency Management Norfolk Island (EMNI) moved the island to a red alert Saturday afternoon, meaning people should stay inside until further notice.
The storm was downgraded from a category three to a category two system but is still set to bring destructive winds, heavy rain and abnormally high tides.
Much of the island has lost power.
Norfolk Island's Emergency Controller George Plant said gale-force winds and heavy rain started to ramp up around the island on Saturday morning.
"We're happy that it's been downgraded to a category two again, but still, with 155km an hour winds, we're expecting some sort of damage," he told the ABC.
Norfolk Island resident Kate Lemerle said winds rapidly intensified early on Saturday.
"The island has never had a cyclone of this magnitude and none of our houses have built to cyclone standards," she said.
"So it is unknown whether the roof will blow off or whether I will come out the other side completely intact."
Monday, Tuesday predicted to see heavy rain
Strong winds are already being felt in the north, with Waka Kotahi issuing a strong winds warning late this afternoon for the Auckland Harbour bridge.
"Please take extra care especially if you are in a lighter or high-sided vehicle or riding a motorcycle."
The storm is due to track across Northland before moving south to Auckland, Coromandel, Waikato, Bay of Plenty and Gisborne on Monday and Tuesday.
Forecasters are warning of strong wind, heavy rain and big seas.
MetService meteorologist Lewis Ferris said the cyclone would bring widespread severe weather.
The cyclone had taken a more eastern track over the last few days, but there was still disagreement over where the central point will lie when it made landfall, Ferris said.
"It's still looking like Monday-Tuesday are going to be the biggest days for the weather with the approaching cyclone. The worst impacts, where they are and when they occur, are still going to be riding on where the track of the cyclone actually eventuates."
The storm is due to track across Northland on Sunday before moving south to Auckland, Coromandel, Waikato, Bay of Plenty and Gisborne on Monday and Tuesday. It is possible that even Wellington could see some impacts, MetService said.
MetService has issued heavy rain and strong wind watches ahead of its arrival.
Travel warnings issued
Meanwhile, the government is urging people to avoid non-essential travel in areas that could be hit by Cyclone Gabrielle.
Air New Zealand has cancelled several flights.
Emergency Management Minister Kieran McAnulty said safety trumped the disappointment of scrapping weekend plans.
"We would urge people, despite the inconvenience this would naturally cause, to heed that advice, because it is not given lightly. We are taking this very seriously. Depending on how this tracks it could be quite severe and we're just asking people to take it seriously."
McAnulty said he had assurances government agencies and local civil defence services would update their social media channels regularly.
People were also being urged to stock three days' worth of food and water and prepare for possible power outages.
Supermarkets have urged shoppers to be patient as people stocked up on essential supplies.
St John Ambulance said it was scaling up in preparation for Cyclone Gabrielle.
Spokesperson Dan Ohs said St John had increased deployments in Northland, Coromandel, Auckland, and Bay of Plenty.
There would be extra ambulances and four wheel drives on the ground, he said.
"For us it looks like additional ambulances where that's relevant and in particular, four-wheel-drives. We're also in discussion with Wellington Free (Ambulance). Wellington Free have a rescue unit capability and four-wheel-drive resources."
Parents in Auckland are likely to receive communication from their children's school this weekend about Cyclone Gabrielle.
Yesterday, the Ministry of Education advised Auckland schools that they must decide individually whether to stay open or close in response to the storm. The decision would be based on schools' assessment of health and safety risk of their situation.
Maraes prepare to help
A number of maraes in Northland may be available as welfare centres when Cyclone Gabrielle hits the region.
A health organisation based near Kaitaia, Whakawhiti Ora Pai, said it had been talking to maraes in the area.
General manager Errol Murray said several marae are prepared to step in if needed, including Potahi Marae in Te Kao, Waiora Marae in Ngataki.
Murray said they had also been doing welfare checks on vulnerable communities ahead of the cyclone, as well as preparing food packs and water.
And an iwi in the far north said community support networks developed during the Covid-19 pandemic had made it more resilient to face sudden weather events.
Te Runanganui o Te Aupouri chief executive Mariameno Kapa-kingi said they had already started doing welfare checks and stocked up on supplies and water ahead of the cyclone.
"We did a lot of this work ... communities (in Northland) are still very Covid-aware, right, so a lot of the work we did then is actually carried forward into capacity that we have today to deal with this."
South in Tairāwhiti's Tolaga Bay people were on edge.
Five inches of silt covered Suesanne Kutia's property during the recent Cyclone Hale.
The prospect of more bad weather was making people feel stressed and anxious, but they were prepared, she said.
Kutia said her grandmother and two other family members drowned during Cyclone Bola in 1988.
You can find the latest advice from Civil Defence here.
The latest MetService warnings are here.
- RNZ /w ABC