Here comes the heat: Widespread warmth forecast for NZ later this week; Hawke’s Bay to push 30C

• MetService is forecasting a warm end to the week, with a northerly flow nudging temperatures toward 30C in Hawke’s Bay on Friday and Sunday
• A meteorologist says the widespread warmth will be noticeable on Thursday: especially in centres not used to early November temperatures approaching the mid-20s.
• The warmth arrives on the heels of a front delivering showery conditions around much of central New Zealand today and tomorrow

The whole of New Zealand is in for some abnormal spring warmth toward the end of this week – with hotspot Hawke’s Bay in for a run of temperatures pushing 30C.

The heat is set to arrive Thursday, on the back of winds ferrying subtropical air over the country and driving temperatures much higher than many Kiwis will be used to at this time of year.

On Thursday and Friday, MetService is forecasting highs of 22C (both days) in Auckland; 23C and 22C in Hamilton; 21C (both days) in Tauranga and 23C (both days) in Thames.

But the mercury will rise the highest along the North Island’s East Coast: temperatures are forecast to hit 28C and 29C in Napier and Hastings respectively on Friday and Saturday.

“It may well be getting close to 30C ... so we’ll be keeping a close eye on that,” MetService forecaster Dan Corrigan said of Hawke’s Bay’s outlook.

Those temperatures would prove the warmest for spring so far, beating the 28.4C recorded in Christchurch on October 23.

A maximum of 25C is meanwhile forecast for Masterton on Thursday; while further north, Gisborne is expected to get a run of days reaching 26C from Friday.

It’s a similar story in the east of the South Island: Christchurch’s temperatures will hover around the mid-20s from Thursday to Saturday.

“Thursday afternoon will be a particularly warm one for eastern parts of the South Island,” Corrigan said.

“Ashburton is forecasting a high of 27C then, which is 9C above its average daytime high for November.”

Other centres in line for unusual November highs include Dannevirke (22C on Friday), Whanganui (24C on Friday and Saturday), Invercargill (23C on Thursday) and Alexandra (26C on Thursday).

Corrigan explained the big driver behind the late-week warmth: a northerly wind flow sweeping down on to New Zealand and over the main ranges of both islands.

“As that air descends across the mountains, that’s what’s going to produce those somewhat higher-than-normal early November temperatures in eastern places.”

But the unseasonable heat was book-ended by bouts of unsettled weather around the country – starting with a front moving up the South Island today and likely to bring showery conditions over parts of the North Island tomorrow.

“Central parts of New Zealand are likely to see some rain on Wednesday – that’s from southern Waikato down to Wellington and Nelson – but then, for most places, weather is expected to be dry for the rest of the week,” Corrigan said.

“Our next real weather-bringer is going to be a front that arrives in the lower South Island on Friday morning – that’s going to bring a change to slightly cooler temperatures for a while in Southland and Dunedin.

“But it will likely just be a brief, south-west flick for the bottom of the South Island going into the weekend and doesn’t look like it will have much of an effect on the north.”

Jamie Morton is a specialist in science and environmental reporting. He joined the Herald in 2011 and writes about everything from conservation and climate change to natural hazards and new technology.

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