A belt of intense rain hit parts of Auckland this afternoon, although the the central city missed the most heavy falls.
Heat and humidity in the City of Sails caused thunderstorms to develop in the ranges to the west which then drifted across much of the region.
"The most intense parts of the rain were in the southern part of Auckland, around Pukekohe, Bombay and towards the Manukau Harbour, and also the Waitakere Ranges," said WeatherWatch analyst Philip Duncan.
"That was where the worst of it was around Auckland, but also western Waikato."
The Kaitaia area in the Far North didn't escape either, although most of the rain fell in rural districts.
"All of these areas have seen big flair-ups this afternoon. They've almost started to fade away as quickly as they started," Mr Duncan said.
As well as thunderbolts, hundreds of lightning strikes were recorded around Auckland, particularly near Pukekohe, towards the Manukau Heads.
In Pukekohe, the deluge also caused surface flooding.
"If these downpours had been in the city it would have been a very different story," Mr Duncan said.
"These were some of the more intense downpours I've seen in Auckland for some time."
The thunder in Auckland was now out to sea in the east, but was continuing in parts of Waikato, the "thunderstorm alley" of the North Island.Storms there could be expected from Ngaruawahia to Te Kuiti.
"It's a long line of thunderstorms," Mr Duncan said.
"It's just like Auckland - not everybody gets it. Some people have blue sky on one side, clouds on the other."
At Eden Park, where New Zealand are taking on Pakistan in the final cricket one-dayer, a heavy shower forced players to head for the grandstand.
MetService has this evening released a severe-thunderstorm warning for the Waitomo region, for storms heading south, accompanied by heavy rain.
It's also predicting surface or flash flooding and hazardous driving conditions.