MetService is warning a deluge of rain, strong winds and thunderstorms could hit the country this weekend, as several fronts bring unusually hot and humid weather for this time of the year.
The Herald has previously reported a tropical cocktail could cause flooding and disrupt travel.
Heavy rain warnings are in place for the South Island and watches for the Bay of Plenty and the central North Island.
Spirits ahead of two Women's Rugby World Cup quarter-finals, one between the Black Ferns and Wales, at the Northland Events Centre on Saturday evening should hopefully not be dampened by the wet and balmy weather.
Whangārei can expect a high of 23C and rain on game day. The overnight low should only drop to 17C.
Auckland can expect much of the same, with heavy rain possible in the west of the city on Saturday. Two quarter-finals at Waitākere Stadium are likely to be played in heavy rain, with a slightly lower high of 20C forecast on Sunday.
The Black Ferns play Scotland at a Women's Rugby World Cup match at Semenoff Stadium in Whangārei this week. The weather may play a factor in this Saturday's matches. Photo / Michael Cunningham
MetService meteorologist Luis Fernandes said: "A broad area of low pressure in the Tasman Sea results in a persistent northwest flow reaching New Zealand for the next five days.
"This airmass originates in Queensland and the Coral Sea, so it's really warm."
One forecaster has raised fears a water bomb could drop on Auckland and the rest of the upper North Island on Sunday, but this has been allayed as an outlier from other weather models.
Thunderstorms will be around the motu this weekend.
Here's a look at the odds of thunderstorms (or lightning) for each island this weekend.
The UK Met Office warned of a "convergence zone water bomb". A MetService meteorologist did not expect this to eventuate: "We look at several global models with a much higher resolution [than just this one].
"We do have these watches and warnings in place as a series of broad fronts move across the country with the low-pressure system from the Tasman, but nothing like what the UK Met is warning of."
Those warnings included up to 180mm of rain for Mt Taranaki between 3pm on Saturday and early Sunday morning. MetService said streams and rivers could rise rapidly, and surface flooding and slips were possible which could make driving conditions hazardous.
🟧 Severe Weather Forecast 🟨
Warm, humid air is forecast to bring an unsettled period of weather across the country from today & through the weekend
🌧 Heavy rain could cause slips and surface flooding
A heavy rain watch is in place for the Bay of Plenty from Sunday evening until Monday afternoon, while the central North Island and the Tararua Ranges could also have rainfall approaching warning levels until Sunday.
Northerly winds about Wellington may reach severe gale in exposed places on Saturday, MetService forecast.
In the South Island, heavy rain warnings about Nelson and the West Coast from Friday should linger until Saturday evening. This was driven by a sub-tropical jetstream, Niwa said.
