Temperatures could hit 30C this weekend, but there's some rain warnings too

A "taste of summer" is on the way, particularly for those who live in eastern parts of the country, according to the latest forecast.

Temperatures could exceed 30C as we head into the weekend thanks to an Australian heatwave being pushed across the Tasman.

Metservice has issued orange heavy rain warnings, however, for Westland, Fiordland north of George Sound, the Canterbury headwaters south of Arthur's Pass and the Otago headwaters from the early hours of Friday morning into Saturday.

The heaviest rain is expected in Westland, with up to 400mm of rain about the ranges, with peak rates of up to 30mm per hour expected on Saturday morning.

Heavy rain watches are also in place for the Grey District, parts of Fiordland and Southland.

'Unseasonably warm'

The state of Victoria was already experiencing temperatures "between 6 and 16C above average for early November", ABC News reported, as officials enacted a statewide total fire ban.

"For Victoria, we'll see temperatures into the mid to high 30s, even potentially pushing up towards 40C for northern Victoria," Bureau of Meteorology forecaster Jonathan How said. "And then for New South Wales, we'll see temperatures particularly west of the divide climbing up into the high 30s to low 40s."

Here at our lower latitudes, that will translate into unseasonably warm weather.

"We are going to get a taste of summer for the rest of this week and for much of the country, even into the weekend… and this is coming from Australia," NIWA forecaster Chris Brandolina said in a video update.

While Canterbury was off to a fairly mild start on Thursday, Brandolino said they would be "increasing pretty substantially" as the day went on.

"By midday we could see temperatures in the mid 20s near Ashburton, even parts over interior Otago.

"Check out places like Gore, 22C around midday. Look, average high temperatures in this area range from 16 to 19 - those are average maximum temperatures in the month of November, so we're going to be well above that. We're talking in some cases eight, nine, 10 degrees or more above average - and it gets warmer during the day."

Ashburton could reach 28C, and others might even tip 30C: "Rangiora over toward Kurow, over toward Fairlie - a lot of the, I guess, interior portions of interior - well, Canterbury and the South Island toward Otago, Alexandra mid-20s, Tapanui also could be in the mid 20s, Gore mid low to mid 20s, so some pretty impressive stuff."

In the North Island, Brandolino said it would be "a warm day, just not as warm", with low 20s for Hamilton, Auckland and Northland, as well as Hawke's Bay.

On Friday "it's both east and of the east of the north and east of the South Island that's expected to find some very warm temperatures".

"This is midday, and we're talking 27, 26C in Christchurch, North Canterbury, east of Culverton, in and around Kaikoura, some pretty warm temperatures. We could see temperatures approaching or exceeding 30C in this part of the country during the day on Thursday and even on Friday…

"Areas farther south such as Gore and such as interior Otago, probably not going to be as warm. We see temperatures still on the mild side, upper teens in there, 20C, but certainly, a good six, seven, eight degrees cooler on Friday in Gore than it will be on Thursday.

"For the North Island, it'll be eastern parts of the North Island that have the warmest temperatures - you can see over toward Wairoa, Napier… we're going to find temperatures in the low, maybe mid-20s.

"Looks like the warmest temperatures on Friday are going to be over the eastern South Island. But I wouldn't rule out some areas getting close to 3oC. So, while 30C is possible east of the North and east of the South Island, it may be a bit more probable for the east of the South Island."

The warm weather will continue into Sunday, he explained.

"You can see temperatures on Sunday and in portions of the North Island, as well as Hawke's Bay well into the 20s. Meanwhile, much cooler air is expected for the day on Sunday, for the South Island. So your temperatures will be going down."

And with that drop will come rain, he said.

"There will be some heavy rain it looks like Thursday night and into Friday… we see this band of rain coming off Australia, areas of low pressure…

"If you've got plans on Friday to be in the national parks - Fiordland National Park, Westland, Tai Poutini, over toward maybe Arthur's Pass, Aoraki Mt Cook, Mt Aspiring, there's going to be some heavy rain. You're gonna want to stay on top of the forecast, check the latest warnings from MetService and looking at the rainfall forecast… these are some pretty beefy amounts."

Speaking to RNZ's Midday Report, Brandolino added that the capital will not experience quite the same highs as the upper and eastern North Island.

"Wellington won't be bad. I mean, Wellington will be nice - it just won't be 25 or 30."

As for the rest of summer, he said the signs were pointing to a scorcher.

"We haven't issued our summer outlook yet. That'll be later this month, but we can get some insight. Look, La Niña is going to be influencing our weather.

"La Niña is what we call a climate driver. So climate drivers, well, who's basically driving Mother Nature's car? If you know who is behind the wheel, you kind of know which direction you're going. And La Nina tends to give us less westerlies, and it tends to give us more in the way of east to northeast winds.

"And because of that… we're likely to see air flows coming from a warm direction, and we're likely to see temperatures above average for the next three months."

Warnings

MetService has issued several rain warnings for the lower South Island, as an active front moves across the country.

Orange heavy rain warnings were in place for Westland, parts of Fiordland and the Canterbury and Otago Headwaters from the early hours of Friday morning into Saturday.

Meanwhile in the Mackenzie District and across Mid and South Canterbury, Fire and Emergency NZ data showed there was a very high fire risk over the next few days, with the risk of scrub fires at an extreme level.

MetService said the heaviest rain was expected in Westland between 6pm Friday and 1pm Saturday, with up to 400mm of rain expected about the ranges, and up to 200mm about the coast. Peak rates of up to 30mm per hour were expected on Saturday morning.

In Fiordland, up to 200mm of rain was expected north of George Sound, in the 24 hours from 3am on Friday.

There was a moderate chance of both being upgraded to a red warning.

In the Canterbury headwaters south of Arthur's Pass and the Otago headwaters, between 300 to 400mm of rain was expected about the main divide from the early hours of Saturday morning, with up to 150mm expected to fall farther east.

MetService warned streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions were possible.

Heavy rain watches were also in place for the Grey District, parts of Fiordland and Southland.

Fire and Emergency NZ has issued a fireworks ban for parts of Southland in response to the changing weather.

"Although things have been extremely wet in Southland things are starting to dry," district manager Julian Tohiariki said earlier this week. "The weather forecast for Thursday and Friday is for temperatures in the 20s with possible strong winds."

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