More than 1000 lightning strikes have been recorded across New Zealand today, and more are expected, as a band of thunderstorms moves in from the Tasman Sea.
MetService meteorologist Daniel Corbett said a severe thunderstorm watch would likely remain in place for Auckland, Northland, Great Barrier Island and the Coromandel Peninsula at least until tomorrow.
He said a brief reprieve in the stormy weather in Auckland this afternoon would be short lived.
"I wouldn't be out there with my picnic basket,'' Mr Corbett said.
"It's heavy rain in places. There's a risk of hail, frequent lightning - it's pretty awful over the next few hours.''
Over four hours from late morning there had been 1018 lightning strikes recorded across the country, most in a "good cluster'' at the top of the North Island, Mr Corbett said.
"It's a good amount for just that small area in that span of time ... hence why we have a severe thunderstorm watch,'' he said.
Mr Corbett said the weather would remain "a bit wet and yucky'' for most of the day.
WeatherWatch.co.nz said the "active but narrow band of rain'' continued to bring torrential rain and isolated thunderstorms to parts of the North Island.
Analyst Philip Duncan said the threat of a tornado had dropped to be a "low'' risk.
"The front fizzled significantly as it approached Auckland but intensified over Northland. It appears the city has missed the worst of today's narrow but active front,'' Mr Duncan said.
He said there had been an unconfirmed report of a waterspout in Whangaparaoa.