A run of clear skies for the upper North Island will give way to rain and strong winds to cap off King's Birthday weekend and ring in the meteorological winter.
MetService meteorologist Ngaire Wotherspoon said the shift will mark a dramatic end to one of the driest Mays on record for parts of the South Island.
"It's been a very, very dry and settled May, with high pressure dominating the weather situation," she told 1News.
"We are expecting a couple more days of that before quite a marked change over the weekend."
The north and west of the South Island would bear the brunt of the rainmaker, with MetService's severe weather outlook flagging Nelson, Tasman, and inland Marlborough — particularly its ranges — as areas of concern. Westland's ranges were also on the radar.
Wet and windy weather is set to sweep across much of New Zealand over King’s Birthday weekend. (Source: Breakfast)
For the northern half of the North Island — from the central plateau, New Plymouth, and Gisborne northward — significant rain was expected.
"The further north you get in the North Island, the more rain you're probably going to be seeing," she said.
Canterbury and Otago were shaping up as the places to head if you want to dodge the worst of it.
"Those places are looking quite sheltered because it's quite a northerly situation," Wotherspoon said.
A potentially record-dry May
The incoming change brings to an end an extraordinary run of dry weather for much of the South Island.
Christchurch Airport has recorded just 5.4mm of rain this month — around 10% of its usual May total of 58.4mm. The driest May on record for the city stands at 11.2mm, set in 2012.
"Unless they see another 6mm in the next couple of days, it's probably going to be their driest May on record," Wotherspoon said.
"There's a possibility they see a bit of rain on the 31st, but I doubt it's going to be that much."
The dry May fits a pattern forecasters had been anticipating. Earlier this year, meteorologists warned of a significant El Niño developing — a climate cycle driven by warmer-than-usual ocean temperatures in the tropical Pacific, which tends to bring south-westerly winds to New Zealand and drier conditions for northern and eastern areas.
Earth Sciences NZ meteorologist Jon Tunster said at the time that "dryness could become an issue as spring approaches" for areas missing out on their normal winter rainfall.
Winter to bring ... noticeably warmer nights?
The incoming system was expected to bring noticeably warmer nights along with the rain, with overnight temperatures expected to run 4 to 8C above the usual May average across much of the country.
"Ironically, as we hit meteorological winter on June 1, this system is going to bring some quite warm and humid conditions," Wotherspoon said.
"We're going to be looking at some pretty sticky nights ahead."
Wotherspoon stressed the forecast was still evolving.
"This is still very much an evolving weather situation," she said.
"We will, in all likelihood, be sending out heavy rain and strong wind watches and warnings in the coming days — so definitely keep an eye on the MetService website."
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