More heavy rain expected for upper North Island

MetService has issued severe thunderstorm watches across parts of Northland and Auckland, and heavy rain watches from Northland to the central plateau.

MetService meteorologist John Law said there had been been intense bursts of rainfall and flashes of lightning on Monday, with more to come.

Most of the lightning struck off the coast of western Auckland and Waikato, with rain from Northland to Waitomo, he said.

Warm, humid weather provided perfect conditions for the intense rain showers to form, he said.

A heavy rain watch was in place for Northland from 9pm Monday until 10pm Tuesday, and in Auckland/Great Barrier Island from 11pm Monday until 1am Wednesday.

"Periods of heavy rain. Thunderstorms and localised downpours possible with rainfall intensities of 25 to 40 mm/h."

Coromandel's watch also began at 9pm, and would last through to 4am Wednesday, at least.

As for the central North Island, a heavy rain watch is in place from 3am Tuesday until early Wednesday morning for Waikato, Waitomo, Taupō, Taranaki, Taumarunui and Tongariro National Park, with a moderate chance of being upgraded to a warning.

The forecasts follow heavy rain and storms in Auckland, and Canterbury on Friday and Saturday.

MetService earlier issued a severe thunderstorm warning for the Far North before 7am on Monday, which had since lapsed.

"There is a moderate risk of severe thunderstorms with localised downpours (25 to 40 mm per hour) over Auckland and Great Barrier Island from late morning until this evening," MetService said on Monday morning.

"Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips.

"Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain."