Elsewhere, the storm was expected to bring a dramatic fall in temperatures, snow, and more thunderstorms, gales, rain and hail.
Heavy rain watches were in place for the ranges of the Westland District, Fiordland north of Doubtful Sound and the Otago headwaters from 10pm on Sunday at the earliest, lasting until midday Monday at the latest.
Strong wind watches were issued for the Canterbury High Country, central Otago including the Queenstown Lakes District, and Fiordland and Southland from Mataura northwards set to begin at 9pm Sunday and end at 9am Monday.
MetService said: “Severe weather watches may be upgraded to warnings and areas further north are likely to be added in the coming days. Keep an eye on our severe weather pages for updates.”
The national forecaster said an intense trough of low pressure was bringing in the storm. A cold southwesterly flow then follows, embedded with thunderstorms, MetService said.
With it, severe gales were also expected in Gisborne, Hawke’s Bay, Wellington, Taranaki, Waikato, Manawatū, Marlborough and Nelson. Heavy falls were also tipped for the West Coast, Taranaki, Waikato, Manawatū and western parts of the Bay of Plenty.
Most main centres had heavy rain forecast for Monday.
MetService meteorologist Juliane Bergdolt said the strong winds would bring a dramatic temperature shift, with cooler conditions replacing some of the recent sweltering days.
“Maximum daytime temperatures [will be] in the mid-teens for southern parts of the South Island on Monday and Tuesday,” she said.
“The colder air runs northwards across the country, bringing some snowfall to the tops of the Southern Alps for the early hours of Monday morning.”
Raphael Franks is an Auckland-based reporter who covers breaking news. He joined the Herald as a Te Rito cadet in 2022.
