‘Damaging’ storms: Warnings of tornadoes, flooding, slips in place for North Island

A severe thunderstorm watch was in place for much of the North Island overnight and into Wednesday morning, with MetService warning of possible tornadoes in some areas.

According to the MetService website, active bands of thunderstorms are expected to move eastwards across the North Island on Tuesday night and early Wednesday morning.

This may cause “damaging” storms in Northland, Auckland, Great Barrier Island, Coromandel Peninsula, Waikato, Waitomo, Taumarunui, Bay of Plenty, Rotorua, Taupo, Taranaki, Taihape and Wanganui.

These thunderstorms might produce damaging wind gusts of more than 110 km/h in some cases, as well as a possible small tornado, the service said.

The forecast warns that if tornadoes occurred, they would only affect very localised areas but could cause structural damage, including toppling trees and powerlines and making driving hazardous.

Localised downpours of 25 to 40 mm/hr are also expected for areas south of Northland.

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

A strong wind watch is in place overnight for Bay of Plenty, Gisborne, Hawke’s Bay south of Waipukurau, Wairarapa including the Tararua District and Wellington, with winds possibly becoming severe gales at times.

Earlier, electrical storms were approaching the top of the North Island as two jet streams - one from the tropics and the other from Antarctica - merge, unleashing days of thunder, gales, rain and even snow.

The near-dozen warnings and watches began in the early hours of Tuesday morning and last until Thursday morning.

Rain was falling first in Northland and Westland, ushering in up to 18 hours of stormy weather.