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El Niño incoming: NZ's climate to take 'rapid turn' within weeks

Author
Jamie Morton,
Publish Date
Sun, 10 Sep 2023, 1:50pm
Niwa meteorologists are expecting a rapid turn in New Zealand's local climate state later this month, when a long-awaited El Niño is likely to be declared. Image / Niwa
Niwa meteorologists are expecting a rapid turn in New Zealand's local climate state later this month, when a long-awaited El Ni帽o is likely to be declared. Image / Niwa

El Niño incoming: NZ's climate to take 'rapid turn' within weeks

Author
Jamie Morton,
Publish Date
Sun, 10 Sep 2023, 1:50pm

New Zealand鈥檚 climate is about to take a 鈥渞apid turn鈥, a meteorologist says, giving Kiwis a taste of the hotter, drier summer much of the country will experience under El Ni帽o.

There鈥檚 now also a good chance聽聽- which could be formally declared within weeks - will sit among the strongest El Ni帽os seen in the past 80 years, with officials already warning of fire danger and a heightened risk of drought.

For those regions hit hardest by the relentless rain and humidity of three years of La Ni帽a, its counterpart climate driver is expected to bring the reverse set-up, with long periods of summer heat and dryness fanned by persistent westerly flows.

鈥淯sing the data from August, this El Ni帽o is in with the five strongest that have occurred in the last eight decades,鈥 Niwa meteorologist Ben Noll said.

Several of those events came with major dry spells: notably the El Ni帽o summers of 1972/73, 1982/83 and 1997-98, when a horror event cost the country hundreds of millions of dollars.

鈥淲ith its potential intensity being up there with those historically-significant events, there鈥檚 definitely a few flags starting to be thrown.鈥

This El Ni帽o - our first since 2016 - would also come against a background of climate change, and in tandem with another natural driver that had a hand in Australia鈥檚 catastrophic bushfires of 2019-20: a positive phase of what鈥檚 called the Indian Ocean Dipole.

鈥淭his could dramatically reduce the chance of seeing those tropical moisture plumes as we look ahead - so it鈥檚 kind of a double-whammy of climate drivers that are going to be coming on quite strongly,鈥 Noll said.

Before that, however, Noll said things would take a turn within a few weeks, when the atmosphere 鈥渃oupled鈥 with oceans already in an El Ni帽o-like state.

鈥淚n a New Zealand context, this is going to mean that our own weather patterns are likely to take a rapid turn toward an El Ni帽o-like pattern - and that鈥檚 expected to start in the second half of September.鈥

As Niwa picked in its聽, Noll expected to see a significant shift in the frequency and intensity of westerly winds, spelling below-normal rainfall and frequently-warm temperatures for the east of both islands.

鈥淲e could be seeing days exceeding 25C during the second half of September,鈥 he said.

鈥淏y the end of this month, or by mid-October, I think we鈥檒l really have had our first real taste of this El Ni帽o event, and what鈥檚 to come for the rest of 2023.

An incoming El Nino system is raising the risk of drought and wildfire in eastern regions this summer. Photo / Alan Gibson

An incoming El Nino system is raising the risk of drought and wildfire in eastern regions this summer. Photo / Alan Gibson

鈥淔or the likes of Canterbury, eastern Marlborough, northern Otago, Wairarapa and Hawke鈥檚 Bay, but also the Bay of Plenty, Coromandel, Auckland and Northland, the weather is going to be quite a contrast to what we鈥檝e dealt with the last couple of springs and summers.

鈥淪o, it鈥檚 about being prepared for the kind of extremes that are going to be possible for the next six months.鈥

In Hawke鈥檚 Bay, rainfall had already been running at half the normal average, with indications of even drier trends for late September and early October - although a high amount of moisture left in the ground meant there was no imminent threat of local drought.

Hawke鈥檚 Bay Regional Council acting science manager Dr Kathleen Kozyniak said it was too early to say if that鈥檇 happen this summer - but the developing pattern did point to a heightened risk.

鈥淎s usual, we鈥檒l be closely monitoring weather patterns and the status of the region鈥檚 rainfall and soil moisture and sharing information through our website and monthly state-of-the-environment reporting,鈥 Kozyniak told 九一星空无限.

Fire and Emergency New Zealand鈥檚 (Fenz) service delivery wildfire manager Tim Mitchell said conditions forecast for summer were likely to come with higher levels of fire danger on the east coasts of both islands.

Image / Fire and Emergency New Zealand

Image / Fire and Emergency New Zealand

鈥淕iven this year鈥檚 flood events and wet conditions, people will likely find it difficult to understand the wildfire risk New Zealand could be facing soon,鈥 Mitchell said.

鈥淏ut a spell of hot dry windy weather will quickly dry out the grass and vegetation that has grown and will likely grow over the coming months, due to the moist soils and return to warmer weather.

Image / Fire and Emergency NZ

Image / Fire and Emergency NZ

鈥淭his will become a fire risk if not managed.鈥

Fenz was urging people in rural and semi-rural areas to prepare now by keeping grass short, moving flammable materials well away from their homes, clearing gutters and accessways to ensure rapid address numbers were visible, and having a plan of action ready.

鈥淣inety-eight per cent of New Zealand wildfires are caused by people and people can do a great deal to prevent wildfires occurring and to help protect themselves and their property.鈥

Jamie Morton is a specialist in science and environmental reporting. He joined the聽贬别谤补濒诲听in 2011 and writes about everything from conservation and climate change to natural hazards and new technology.

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