The storm hits in Whangārei on Thursday. Photo: RNZ / Nick Monro
Cyclone Tam is pummelling the upper North Island with wind gusts of up to 150km/h and heavy rain.
The severe weather system will bring sustained heavy rain and severe easterly gales to many areas of the North Island and upper South Island through to the weekend.
It was originally a category one cyclone. However, as expected by forecasters, it was reclassified to an ex-tropical cyclone early afternoon on Wednesday.
Forecasters were warning it could still pack a punch.
By Thursday morning, the extreme weather had caused nearly 25,000 properties in Northland to lose power, and FENZ attended more than 120 calls for damage across Auckland and Northland overnight.
Meteorologist Mmathapelo Makgabutlane told Morning Report wind was strong even in built-up places like Whangārei, with gusts of about 96km/h.
Makgabutlane said there had been a bit of rain, but the trouble was caused by the impact of rain and wind exacerbating each other.
Northland was at risk of thunderstorms on Thursday, and Auckland could expect to see them later in the evening.
"Maybe a bit of a complicating factor," Makgabutlane said. "As we know thunderstorms are problematic on their own, but what they're going to be doing is intensifying some local effects."
Multiple electricity outages affected the region covered by Auckland City Council on Thursday, as far apart as Te Arai in the north to Piha in the west.
Warnings and watches in place
MetService has issued several weather warning and watches across the country. Warnings were widened on Thursday for some regions and a new area added.
MetService issues severe weather warnings whenever there is an expectation that any of the following weather conditions will occur within the next 24 hours. There could be more issued as the system moves over the country.
Check the latest MetService warnings on its website.
Northland was on Thursday under an orange heavy rain warning with peak rainfall rates of 15mm to 25mm an hour forecast through to the evening. Severe gales were also expected through to the evening with damaging wind gusts.
An orange strong wind warning was issued for Auckland and Great Barrier Island until midnight Thursday and an orange heavy rain watch was in place through to early Friday morning.
Coromandel Peninsula continued an orange rain warning through to Friday afternoon. There was a low chance of upgrading to a red warning.
Parts of Bay of Plenty west of Whakatane, including Rotorua and the Kaimai Range, were under an orange rain warning through to midday Friday.
The warning for Gisborne/Tai Rāwhiti had been widened. The area north of Tokomaru Bay and Bay of Plenty northeast of Omaio, had an orange rain warning through to midday Saturday, with a low chance of upgrading to a red warning.
Tongariro National Park has been added in to the heavy rain watches, periods of heavy rain forecast through to Saturday morning.
Strong wind watches are in force for Coromandel Peninsula, and Waikato and Waitomo, through to midnight Thursday, and for Taumarunui and Taihape, and parts of Taranaki to early Friday morning.
Heading south, parts of Tasman have been issued an orange rain warning from Thursday night until midnight Saturday. MetService said there was a low chance of this warning being upgraded. Buller is under a strong wind watch through to Friday morning.
Electricity outages in the Far North as severe weather from Cyclone Tam hits the Upper North Island. Photo: Northpower / Screenshot
Official advice
Cellphone towers have been without power in Northland affecting mobile reception. One NZ is opening up satellite text as an option for those with 4G. Landlines are still operating and 111 calls can be made from them.
Civil Defence Northland said local emergency services, councils, contractors, and partner agencies, including health and welfare agencies, had all been working on their preparations and were ready to respond.
With many people likely to be heading away for the Easter holidays, drivers are urged to drive to the conditions and plan for disruptions.
The rain was already setting in on Wednesday, Photo: MetService rain radar
MetService said there is a risk of surface flooding and slips across the country.
Auckland Transport said there would be a higher safety risk out on the roads, and some public transport services may also be affected, especially ferries.
"Make sure you check the forecast when planning any weekend travel or activities and check it again for any changes before you go out. Don't forget, if you're heading to another region, check the weather there too," Auckland Emergency Management general manager Adam Maggs said.
"A bit of rain has softened ground conditions over the last week so we could start to see some surface flooding if heavy rain eventuates."
Power suppliers have told customers to charge their devices as the weather may cause outages, mostly caused by trees and branches coming down over power lines.
RNZ is the statutory civil defence lifeline radio broadcaster and will be providing vital information and updates as they come to hand. Check out the frequencies here.
