Thunderstorms, severe gales, hail, heavy rain, snow expected to lash New Zealand in coming 72 hours

• Heavy rain, hail and severe gales are expected to lash both islands in the coming days.
• Forecasters are warning heavy rain and “damaging” winds may retrigger flooding and slips from earlier this week.
• A warm air mass from Australia will mean unseasonably higher temperatures across New Zealand.

Thunderstorms, heavy rain and severe wind gusts are expected to lash the country during 72 hours of wild weather that will see out the last days of winter.

Much of the South Island and parts of the lower North Island are under strong wind and heavy rain watches for coming days with the first alert taking effect later this afternoon.

MetService is warning much of the country should expect damaging winds and rain but the South Island and lower parts of the North Island would bear the brunt of the incoming wild weather.

🟡Latest Severe Weather Info🟡

Watches have been issued ahead of the next approaching weather system

Wind gusts could reach severe gale in some places, while elevated areas could be in for periods of heavier rainfall💨🌧️

See full details at https://t.co/qHyE5zzql5 pic.twitter.com/UB7vtgBGOE

— MetService (@MetService) August 27, 2024

There is also a threat of thunderstorms and hail, and snow is expected in alpine regions of the south.

It comes after heavy rain flooded Wellington earlier this week and slips covered roads on the West Coast.

Forecaster Niwa said warm days and mild nights are in store as an Australian air mass flows across the Tasman Sea today and tomorrow.

Temperatures are expected to climb into the 20s in eastern regions today.

An Australian air mass will flow across the Tasman Sea on Wednesday-Thursday, bringing mild nights & warm days to many parts of New Zealand 🌡️

Max temperatures will reach into the 20s, being 4-8˚C above average for the time of year.

🌬️ More warm air will blow in this weekend... pic.twitter.com/CSAwIyFejO

— NIWA Weather (@NiwaWeather) August 27, 2024

MetService meteorologist Mmathapelo Makgabutlane said unsettled weather would be the trend to finish the week.

“It will be very easy to kind of get lost and confused with all the different weather systems in the next few days.”

She said most areas of the country should expect some wind and rainfall but the South Island and lower parts of the North Island would see the worst of it.

MetService is warning severe gales may damage trees, powerlines and unsecured structures in Wairarapa, Wellington and the Marlborough Sounds.

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These areas will be under a strong wind watch from 4am Thursday for 12 hours.

It comes after widespread surface flooding hit the Wellington region on Monday, which closed multiple roads and caused rivers and streams to swell.

Makgabutlane urged residents to stay vigilant as rainfall and strong winds on the already sodden ground could make for more flooding.

Flooding in Otaihanga Domain, Paraparaumu, on Monday. Photo / David Haxton.

Further south, the Canterbury High Country, Fiordland, Southland northwest of Riversdale, Queenstown Lakes District and Central Otago will also be under a strong wind watch from 4pm.

The headwaters of the Canterbury lakes and rivers south of Arthur’s Pass will be under a heavy rain watch for 20 hours.

MetService is warning thunderstorms will be embedded in the heavy rain and rainfall amounts may approach warning criteria.

Odds for thunderstorms (lightning) over the coming days.

🔴 high
🟠 medium
🟡 some

More active weather is expected this weekend. pic.twitter.com/snRIX3xVGf

— NIWA Weather (@NiwaWeather) August 27, 2024

The forecaster said these thunderstorms will include localised heavy rain, snow above 900 metres, hail, and strong wind gusts.

Makgabutlane said there is also a low risk of thunderstorms on the East Coast from Bay of Plenty down to Napier this afternoon.

A heavy rain watch is also in place for 24 hours for the Tararua Range starting from 11am.

The ranges of Westland south of Arthur’s Pass will also be under a heavy rain watch for 21 hours from midnight.

Makgabutlane said as we come into the weekend, another weather system would move and bring more wind and wet weather.

“Because the winds are so strong, it is quite a fast-moving system.”

Rachel Maher is an Auckland-based reporter who covers breaking news. She has worked for the Herald since 2022.