Weather: First big cold snap of the year coming this weekend

  • 15/03/2024
Two road snowfall warnings are in place.
Two road snowfall warnings are in place. Photo credit: Getty Images

Autumn is about to feel a lot cooler as a cold change moves northwards on Friday.

MetService is forecasting blustery thunderstorms from late afternoon for some parts of the country followed by snow flurries over the highest spots in the evening today.

Road snowfall warnings are in place for Arthur's Pass and Porters Pass (SH73) until 9pm Friday.

"Snow is expected to affect higher parts of the road this afternoon and evening, however little if any is likely to accumulate on the road," MetService said.

WeatherWatch said the cooler temperature is brought by two cold fronts moving up the country, ahead of another big high-pressure zone moving in for next week.

"Rain and showers, drizzle patches too, move up the country today (Friday) - but some regions may get very little rain due to the mountains and ranges blocking it. There are large dry areas too," WeatherWatch said.

As for thunderstorms, MetService said "unstable south-westerlies" over the lower South Island affect the southern coast from Fiordland to Dunedin, bringing a low risk of thunderstorms during Friday morning and afternoon.

"A front moves northwards along the west coast of the South Island bringing bursts of heavy rain and a low risk of embedded thunderstorms to Westland this morning and to Buller until afternoon. The front continues northwards across the west of the North Island in the evening and night, with a low risk of thunderstorms as depicted on the chart," it said.

"A southerly change moves across Canterbury during the afternoon with a low risk of thunderstorms for the High Country and north Canterbury Plains. The risk of thunderstorms becomes moderate late afternoon and in the evening with the southerly change as it moves across eastern Marlborough, the Marlborough Sounds, Wellington, Kapiti and southern Wairarapa."

The forecasting agency added that any thunderstorms that occur will produce brief heavy rain, small hail and strong wind gusts of up to 90km/h.

A low risk of thunderstorms then spreads onto the northern Wairarapa coast at night.

Crisp autumn mornings this weekend

MetService said crisp autumn mornings are on the way this weekend with minimum temperatures dropping to single digits for the South Island and parts of the North Island. Twizel is forecast to be the coldest with minimum temperature expected to be -1C on Saturday, followed by Timaru at 2C.

On Sunday, most eastern and northern regions of both main islands dry out further while a few showers and more clouds remain in the west. The lower South Island (mostly Southland and Coastal Otago) will still have colder air plus clouds and showers coming off the Southern Ocean, WeatherWatch said.

MetService's short forecast:

Northland to Whanganui, also Coromandel, Bay of Plenty, the central high country, Gisborne and Hawke's Bay

Periods of rain, briefly heavy, easing from the south this afternoon, then clearing to fine tomorrow.

Manawatu to Wellington, also Wairarapa

Partly cloudy. Showers and cold southerlies developing this evening, possibly heavy and thundery, clearing to fine tomorrow morning.

Marlborough and Canterbury

Rain about Canterbury with cold southerlies, spreading to Marlborough this afternoon where thunderstorms are possible. Clearing to partly cloudy early tomorrow.

Nelson, Buller and Westland

Showers, possibly heavy, clearing to fine later today. Showers return to Buller and Westland tomorrow.

Fiordland, Southland and Otago

Showers, with snow above 600 metres, clearing Otago this afternoon and inland Southland tonight. Rain spreading north tomorrow afternoon, then easing to showers in the evening.

Chatham Islands

Rain today. Showers tomorrow, easing.