As wet weather drenches much of the country, localised thunderstorms are possible over the next couple of days, MetService says.
The effects were seen early this morning in Auckland with flights being delayed and bouts of lightning in the CBD, leaving one person struck by lightning in South Auckland.
St John Ambulance said they were called to Māngere shortly after 8.30am and took one person to Middlemore Hospital in a moderate condition.
A manager at Happy Campers in Māngere said the person was a member of staff and that while St John Ambulance attended, she was "perfectly okay" and had gone home.
Auckland man, Jordan Swarbrick, who works next door to the Happy Campers office, said it felt like an earthquake when the building next door was struck by lightning. He says at its peak the thunder was so loud he and his work mates used earplugs.
"There were a couple of strikes right above us, they were shaking the building a bit, the power cords were kind of swinging suspended from the roof, almost like a mini-earthquake."
Niwa's Chris Brandalino said that the wild weather broke the record for the wettest December hour in Auckland, however, the worst has passed and mainly fine conditions are expected for the rest of the day.
MetService meteorologist James Millward said: "If you're up North you've probably woken up with a big bang, you've got a cold front moving over the North Island this morning. It should make way to a fairly fine afternoon for a lot of the West of the North Island."
The view from the @snapithd cam of the Viaduct Harbour in #Auckland currently. Intense localised falls this morning (up to 28mm/hr) are severely reducing viability in the region. Take extra care this morning with the severe weather, especially if you are out on the roads. ^JM pic.twitter.com/plGZRGcSU7— MetService (@MetService) December 3, 2018
Down south there is a low to the south west of the country which is spinning into the Westland, Fiordland area today, and that's bringing heavy rain. A few thunderstorms have been reported around Aoraki/Mount Cook this morning.
"We have actually got a severe thunderstorm watch in place for areas in Westland and Southland this afternoon right through to 9pm this evening," he said.
The thunderstorms are causing significant disruption to both international and domestic flights at Auckland Airport.
An Air New Zealand spokesperson said it was experiencing delays due to gate availability while a number of departures have been cancelled. A number of Air New Zealand aircraft are being inspected because of possible lightning strikes.
The intense thunderstorms in the North Island have also led to heavy rainfall rates of roughly 25mm per hour.
"The good news for Auckland and the Waikato as well which is also experiencing these thunderstorms, is they do pass through relatively quickly. For Auckland, by the afternoon we are looking at quite a sunny day. It's not all bad news," Mr Millward said.
Power outage in parts of Auckland
Lightning strikes have caused power outages in parts of rural Auckland this morning including Whangaparaoa, Piha, Laingholm, Oratia, Helensville, Maraetai, and Clevedon.
Vector said network managers were back-feeding electricity to affected areas from nearby powerlines and power was being restored where possible.
People in those areas may be without power until it is safe for outage crews to repair the faults, Vector said.
According to Niwa, 130 lightning strikes were reported in the Auckland region in five minutes.
MetService forecasted a showery and humid start to the week.
Thunderstorms all over today! While the most intense action at the moment is all in the upper north, these two southern areas have the potential for heavy downpours and hail later today. Details: https://t.co/GZIq9Jlbrw ^AH pic.twitter.com/f5qU6NKrAv— MetService (@MetService) December 3, 2018
Thunder and lighting roll overhead in Papatoetoe as Auckland is hit by thunderstorms. pic.twitter.com/Wd4IWkP0zd— RNZ (@radionz) December 3, 2018
Auckland hit by powerful thunderstorms, power outages and flights cancelled, more details to come. pic.twitter.com/aPVhhY8j66— RNZ (@radionz) December 3, 2018
Most of the North Island woke up to dark skies, while the east coast of South Island had a foggy morning.
A very active cold front is moving onto the NI this morning bringing thunderstorms right across the upper NI. #Auckland @AucklandCDEM and #Hamilton can expect heavy showers and thunderstorms to roll over the cities within the next hour.Radar @ https://t.co/prKU7O2R01 ^JM pic.twitter.com/jhqih8m79Y— MetService (@MetService) December 3, 2018
⛈ in the north but fog to start the day for the east coast of the SI. A shot from the Christchurch @snapithd camera at 7am, but this is clearing now.Timaru, Oamaru and Kaikoura also started the day with some fog.Whats in store for the rest of the day?https://t.co/5v4V4jknSd ^JM pic.twitter.com/9g1RTLzXw7— MetService (@MetService) December 3, 2018
West Auckland currently seeing some localised intense rainfalls ~25 mm/hr underneath the thunderstorms. Stay safe, avoid driving through any floodwaters. Things dry out quickly once the cold front passes thru later this morning. https://t.co/7k3nmdWQwx ^GG @AucklandCDEM— MetService (@MetService) December 3, 2018
Meanwhile in the Tropics, Cyclone Owen was named by TCWC Brisbane Sunday evening, the second cyclone of the season in the South Pacific/Coral Sea area. Owen is forecast to remain slow moving over the Coral Sea this week and poses no threat to New Zealand.