A thunderstorm is moving rapidly across the North Island.
MetService has issued a severe thunderstorm warning for Northland, Auckland, Great Barrier Island, Coromandel Peninsula, Waikato, and Bay of Plenty.
It said these thunderstorms are moving towards the east-southeast, and are expected to lie near Cape Colville, Little Barrier Island, and outer Hauraki Gulf at 4pm on Tuesday, and near Whitianga, Coroglen, Matarangi, Hot Water Beach, Hahei, and Kennedy Bay at 4:30pm.
"A very fast-moving, intense cell could see wind gusts briefly exceed 110km/h," MetService said on Twitter.
"Lightning has been frequent around the cell and heavy rain is likely too but accumulations won't be huge due to the fast-moving nature of the thunderstorm."
MetService said these thunderstorms are expected to be accompanied by "damaging wind gusts" and "frequent lightning".
"Very strong wind gusts can break branches from trees, damage roofing, and make driving hazardous especially for high-sided vehicles and motorcycles," it said in the severe thunderstorm warning.
"Frequent lightning is dangerous to people and livestock, especially those exposed outdoors or on the water, and can cause power surges and damage to electrical equipment."
In Auckland as a result of the storms, a high wind alert has been issued for the Harbour Bridge and lanes could close between 8pm and midnight on Tuesday.
"As such there will be no barrier shift today and the lane configuration will remain four in each direction," Waka Kotahi NZTA said.
"Motorists are urged to drive to the conditions, look out for electronic message boards which will indicate lane closures and reduced speeds, and stay within their lane while travelling across the bridge."
For the South Island, there is a moderate risk of thunderstorms to Buller, Westland and the adjacent alps, and Fiordland for Tuesday. There is also a moderate risk of thunderstorms for Dunedin, Clutha, and coastal Southland in the afternoon.
"Any thunderstorms that occur will bring localised heavy rain with intensities of 10 to 25mm/h, and hail of 5 to 15mm diameter. There is also the risk of a small coastal tornado about the West Coast," MetService said in its thunderstorm outlook.
On Wednesday, there is a moderate risk of thunderstorms over the North Island from Auckland to Manawatū and across to Bay of Plenty, and over the west of the South Island.
There will then be a low risk of thunderstorms on Wednesday afternoon over the North Island from Auckland to Bay of Plenty and southwards to Manawatū.
There's a moderate risk across the West Coast and areas near the alps during the afternoon and evening, and spreading to Horowhenua-Kapiti Coast and Taranaki at night. Coastal Southland, Clutha, and Dunedin also all have a moderate risk of thunderstorms in the afternoon and early evening on Wednesday.
The unsettled weather is due to stay for a little while longer. MetService said earlier on Tuesday that a jet stream is forecast to hang around New Zealand until the end of November.
"This means the weather will stay on the changeable side and while there will be breaks, it's unlikely we'll see an extended run of settled weather before Dec," it said.
