Tokoroa's Kinleith Mill closure is to be decided by the end of the month and politicians and family gather for the final day of Dame Tariana Turia’s tangihanga. Video / NZ Herald
Dry conditions across the top half of the country are expected to intensify and expand over the next two weeks, with little rainy relief in sight
A meteorologist says parts of Northland could be “on the cusp of meteorological drought” by the end of next week
The situation has been partly caused by cooler southwesterly and southerly flows that have made for a run of abysmal summer days in Wellington
Meteorologists are closely watching fast-drying conditions across the upper North Island – with one warning some areas could be on the edge of drought within days.
The New Zealand Drought Index showed dry to very dry conditions across swathes of the North Island, with the tip of the north now running “extremely dry”.
“By the end of next week, some areas of Northland could be on the cusp of meteorological drought,” Niwa meteorologist Chris Brandolino said.
For Northland, Waikato and Auckland, the weather outlook offered little significant rainfall, which Brandolino said was likely to “intensify” the dry pattern.
Many regions north of the Central Plateau had already lost 80mm-90mm of rain over the past 15 days, putting them at a significant moisture deficit.
Source / Niwa
“If we’ve lost 75 to 85mm of rain over the past 15 days, that means you have to make it up, otherwise you’ll be in deficit – it’s like a bank account,” Brandolino said.
“And when you look at the rainfall forecast for the next 10 days, we would still be in deficit by 70mm of rain.”
Brandolino said it was possible a period of northerly flows around January 18 and 19 could bring some rainy relief to parched regions – but that wasn’t guaranteed.
“But between now and then, we’re seeing very little rain, and that dryness is going to expand over the northern half of the North Island.”
Amid the drying conditions, Auckland’s water supply situation remained stable.
“Typically, our peak demand period is in February, so we’ll continue to monitor the weather forecasts, dam storage levels and network performance to ensure stable water supply over the coming weeks,” Watercare’s head of water Sharon Danks said.
Watercare had restored its Pukekohe water treatment plant, providing up to 5 million litres per day, while its two Waikato plants could treat up to 225 million litres from the Waikato River each day if needed.
“Right now, the second plant isn’t operational as we have a good amount of water in our dams and don’t need to be maximising production from the Waikato,” Danks said.
“But it certainly provides a good safety net if the weather does turn out to be drier than expected.”
Source / Niwa
Brandolino said conditions in the north had come about from the strong power of sun at this time of year – stripping from the air 4mm to 6mm of moisture each day – but also recent dominant southerly and southwesterly flows.
For eastern and lower North Island especially, they’d made for a run of abysmal cold, wet and windy days, with the mercury in Wellington rising only as high as 15C on Monday.
“While these are expected to be the highest waves of the week, Wednesday is expected to bring rough sea conditions again as briefly strong southerlies accompany an approaching front.”
Further north, however, Brandolino said these southerly flows had been arriving with little moisture left in them to ease deficits.
In contrast to early December’s abnormal heat, Auckland reached a high of 22C on Monday, with sunny conditions but low humidity.
“And part of the reason for that is the airflow is coming off the Central Plateau: it’s a down-sloping, warming, drying wind.”
Makgabutlane said that, while there’d be warmth across the south on Tuesday – including a forecast 30C high in Otago – another cold front was set to sweep up the country on Wednesday.
After that, clearer conditions were expected for many areas in the latter half of the week – but eastern regions were likely to remain mostly cloudy and cool, with occasional showers lingering.
In the lower North Island and eastern parts of both islands, daytime highs would struggle to climb past the mid to late teens.
The picture might have been markedly different had a warm-and-wet La Nina climate pattern formed – as had long been anticipated – but Brandolino said this now looked increasingly unlikely.
He said holidaymakers seeking the most summer-like conditions in New Zealand over the next two weeks were most likely to find them in the southwest of the country, with temperatures there reaching up to 24C in some places.
“If people want to find summer, go to the national parks and the western and southwestern part of the South Island.”
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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