The upper North Island will be ravaged by hundreds of thunderstorms this afternoon.
Torrential rain and thunderstorms are heading in from the west of the North Island, and should hit this afternoon predicted WeatherWatch.co.nz.
Auckland and Northland will be hit with the worst of the weather.
Weather analyst Philip Duncan said this was one of the most active thunder bands seen for some time.
"These thunderstorms may produce localised flash flooding and produce damaging tornadoes.''
Any tornadoes hitting the country would be on a small scale, unlike the previous tornadoes causing damage in Auckland and New Plymouth earlier this year he said.
The Lightening Tracker has already detected more than 1150 strikes west of Auckland and Northland.
The band of torrential rain and thunderstorms is hovering about 150km west of Piha beach in west Auckland, and is on the move he said.
The site has issued a Storm Alert advising residents and motorists to take extreme care this afternoon with the risk of flash flooding, hail, isolated small tornadoes and frequent thunderstorms as the front moves through in the next few hours.
