Thunderstorms are expected to hit parts of the North Island today, bringing intense bursts of rain as they pass through.
MetService said it's an "electrifying time ahead" as an unstable northwest flow covers the North Island and northern South Island on Tuesday.
The weather forecasting agency said there is a low risk of thunderstorms for northern parts of Nelson/Tasman and Marlborough, Horowhenua to Wellington, and Wairarapa until late afternoon.
A heavy rain watch is also in force for Wellington and Wairarapa including the Tararua Ranges until 9pm Tuesday.
Over the remainder of the North Island, daytime heating and wind convergence are expected to cause shower activity to increase for a time in many places, MetService said.
"There is a low risk of thunderstorms for most of the North Island this afternoon and evening, as drawn on the chart. However, for Auckland, Waikato, northern Taupo, Bay of Plenty, the ranges of Gisborne, South Taranaki, Whanganui, Taihape, Manawatu, the Tararua District, and much of Hawke's Bay, the risk is considered moderate during this time," MetService said.
"Any thunderstorms that occur will likely be accompanied by heavy rain with intensities of 10 to 25mm/h, and small hail. However, from Waikato across to Bay of Plenty, including Rotorua, there is a low risk that slow-moving thunderstorms could become SEVERE and produce localised downpours with intensities of 25 to 40mm/h."
No thunderstorms or significant convection are expected elsewhere in New Zealand on Tuesday.
