A roof has been ripped from a Bermuda Rd preschool in St Helliers by high winds, and a tree has reportedly been hit by lightning in Manurewa.
Fire and Emergency NZ is responding to multiple emergency callouts around the city.
A New Zealand Herald reader said West Auckland was being lashed with a "huge torrential downpour".
The reader said there had been several claps of thunder.
She said one felt like it lasted for at least 30 seconds and was so loud her husband went to check on their children.
Lifelong Manurewa resident Brendan Lambert said his living room lit up with flashes of lightning, followed closely by cracks of thunder.
Not long after it began raining so hard he thought the roof had sprung holes and the rain was coming directly into the ceiling.
"It was the most extreme 5-10 minute storm I've experienced in Manurewa," he said.
Parts of the North Island have been hit by more than 900 lightning strikes so far this evening.
Severe thunderstorms earlier detected off the west coast of Auckland hit the city about 8.15pm.
"These thunderstorms are expected to be accompanied by large hail and damaging wind gusts," MetService says.
The forecaster warned large hail could cause significant damage to glasshouses and vehicles and make driving conditions difficult.
"Very strong wind gusts can break branches from trees, damage roofing, and make driving hazardous especially for high-sided vehicles and motorcycles."
People in northern parts of the North Island are being warned to brace for severe thunderstorms this evening, as a large trough sweeps in from the west.
MetService meteorologist Curtis Hayes said the storm was hitting Waitomo about 7.30pm and quickly making its way north towards Auckland.
Lightning strikes had already been detected over South Auckland, with forecasters warning at 7.15pm: "The main band of activity is still out to sea, but will be over the city in about an hour or so".
"Around 900 lightning strikes had already hit the North Island so far, with more activity happening offshore. This is likely to continue through the night," Hayes said.
A severe thunderstorm watch is now in force for Northland, Auckland, Great Barrier Island, Coromandel Peninsular, Waikato and Bay of Plenty.
The storm is now making its way towards the Hunua Ranges and Clevedon and would then move towards Thames, Firth of Thames, Southern Coromandel Ranges and Kerepehi.
The Ministry of Civil Defence and Emergency Management advises that as storms approach you should:
- Take shelter, preferably indoors away from windows;
- Avoid sheltering under trees, if outside;
- Move cars under cover or away from trees;
- Secure any loose objects around your property;
- Check that drains and gutters are clear;
- Be ready to slow down or stop, if driving.
During and after the storm, you should also:
- Beware of fallen trees and power lines;
Earlier Peter Little said a severe thunderstorm watch was in force for regions between Northland and the Bay of Plenty and Waikato – with the worst expected to arrive sooner rather than later.
Storms due to arrive this evening could be packing wind gusts of 110km/h or even stronger – and there was a "strong likelihood" of localised downpours and hail, especially over the North Island.
