“There are certainly some strong winds in the south already and there’s a band of rain approaching,” he told the Herald.
“It’s still sitting just west of Fiordland at the moment, but it’s expected to move east through the day and bring periods of heavy rain, particularly for the ranges there.”
Strong winds of up to 65km/h have been recorded in some exposed areas of Fiordland and Southland, increasing as the front tracks north, while rain began in Fiordland around 3am.
“Nothing hugely heavy at the moment, but as that front moves more solidly onto the South Island, there will be more significant rainfall in the area,” Lyndon said.
“It’ll be maybe around three-quarters of the way up the South Island by the end of today. And then tomorrow morning, it will be approaching the North Island.”
Further heavy rain watches were issued at 9.40am this morning for the Buller District, Tasman District (west of Tākaka) and the Richmond and Bryant ranges.
MetService’s severe weather team will continue reviewing forecasting models and issue further watches or warnings for the north by 9pm if needed.
The strong northwest front should mostly affect areas like Mt Taranaki and the nearby ranges that are “exposed to that kind of weather system”, Lyndon said.
“Wind will probably be more interesting in the North Island than rain by the time it makes it up to us ... there will certainly be some strong winds from about late morning tomorrow, mainly in those western areas.”
Beyond the front, showery conditions and cooler temperatures should take hold in Aotearoa’s western regions from Wednesday as a cold pool and south-westerly winds arrive.
Taupō is forecast for a high of 18C that day, while Wellington and Dannevirke will only reach 16C.
“Not anything extreme, but definitely a cooler feeling than what we have had over the last week,” Lyndon said.
Until then, high temperatures will persist in the eastern regions.
“As this front progresses up, eastern areas like Canterbury, Christchurch, Kaikōura, Ashburton, and then looking north, again, places like Hastings and Napier, they will actually see some warm temperatures both today and tomorrow.
“It’s the foehn wind effect, we often see that in these north-westerly storms where those eastern areas do have elevated temperatures with that frontal passage.”
Tom Rose is an Auckland-based journalist who covers breaking news, specialising in lifestyle, entertainment and travel. He joined the Herald in 2023.
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