• A low-pressure system in the Tasman is bringing stormy weather, with heavy rain and thunderstorms.
• MetService has issued warnings for Bay of Plenty and northwest Tasman, and warns of strong winds in Northland.
• Meteorologist Mathapelo Makabulane forecasts a “noticeable cooler feeling” as winter begins this long weekend.

A low-pressure system swirling in the Tasman is set to bring “active and stormy” weather for many regions and threatens to close Auckland’s Harbour Bridge this afternoon.

A number of weather watches and warnings are taking hold with increased risk of heavy rain, thunderstorms, small tornadoes and “punchy” winds.

NZ Transport Agency Waka Kotahi (NZTA) said drivers in Auckland need to be prepared for short-notice lane closures or reduced speeds on the Auckland Harbour Bridge this evening.

MetService advises people to keep an eye on conditions this afternoon and evening as heavier rain is expected. Photo / MetService

“Wind gusts of 90-95km/h are forecast for the bridge between 8pm and 10pm tonight, triggering an amber alert,” NZTA said.

There is also an amber alert in place between 2pm and 7pm tomorrow.

“We don’t take the decision to lower speeds, close lanes or close the bridge lightly,” NZTA said.

The weather warnings come after widespread flooding and slips that shut down multiple roads in Nelson.

The front impacting the country was moving eastwards across New Zealand today and early Thursday, followed by a low that would move onto the North Island later on Thursday, MetService said.

From this evening, there is a low risk of thunderstorms for a number of regions, including Northland, Auckland, Great Barrier Island, Coromandel Peninsula, and parts of Bay of Plenty.

Additionally, there is a low risk of a small tornado about Taranaki this evening, which could occur with or without a thunderstorm, MetService said.

MetService advises people to keep an eye on conditions this afternoon and evening as heavier rain is expected for Bay of Plenty, northwest Tasman and the ranges at the top of the South Island.

MetService said there is a risk of thunderstorms and hail for most of the upper North Island as a pocket of unstable air passes over tomorrow.

MetService meteorologist Mathapelo Makabulane told the Herald there is “also that strong wind watch for Northland, where some of those wind gusts could come through in quite a punchy manner”.

Makabulane said many parts of the North Island will get rain and “there could be pockets of heavier stuff within that”.

Watches and warnings

A number of regions are in for a lashing as the fast-moving front is forecast to move onto northern and central parts of New Zealand from the Tasman Sea this evening.

MetService meteorologist Samkelo Magwala said it would be a “wet and windy” week for most of the North Island.

He said there was a risk of severe gales for Auckland and Northland from this afternoon.

Bay of Plenty east of Whakatāne is under an orange heavy rain warning that is expected to last until 4am tomorrow.

Thunderstorms are possible before dawn on Thursday.

Ranges of Tasman northwest of Motueka are also under a heavy rain warning that is expected to lift at 8pm today.

Makabulane said many regions outside the current watches and warnings at this stage are also in for a battering.

“With that risk, that’s outside of the watch and warning area, I’ll say the upper North Island, Northland, Auckland, Coromandel, the western North Island, parts of Waikato and Taranaki - and the top of the South Island and even possibly the western South Island, Buller and coastal Westland could be in line for periods of heavier rain as well,” Makabulane said.

What’s in store for King’s Birthday weekend?

Makabulane said Kiwis should expect a “noticeable cooler feeling” in the air as winter begins this weekend.

She said that would be due to a southwesterly flow over the country.

Makabulane said overall, the long weekend was not looking like a washout at this stage, but there would be periods of showers.

She said coastal areas in the western parts of the country, as well as the lower South Island, could have breezy southwesterlies that might create some large waves.

“That’s maybe a bit of an early heads-up for anybody who is thinking about being near the coast in those areas.”