Giant storm tipped to be biggest over NZ for years

Complex low forecast to hit almost every region and last until midweek

A once-in-a-decade storm brewing in the Tasman Sea will expose Kiwis to some of the strongest gale-force winds in years.

What is unique about the storms due this weekend is how widespread they are across New Zealand.

MetService has severe weather warnings and watches across nearly every region as a complex lowpressure system moves to the east.

MetService forecaster Cameron Coutts says the storms will hit New Zealand from tomorrow and last until the middle of next week, dampening the start to school holidays.

“Most of the country is going to be affected by this set-up. It is such a widespread event,” Coutts said.

“Usually we’ll get tropical cyclones coming out of the Pacific and [they] can result in quite a few warnings as well. But for this one, the whole country’s involved.”

Heavy snow watches are in place for Clutha, Central Otago south of Alexandra, Southland, Fiordland and Stewart Island, and heavy rain forecast in the West Coast could cause flooding.

Conditions that are described as a “weather bomb” by WeatherWatch are comparable to a storm in November 2018, when roads were closed on the West Coast due to flooding.

Strong wind warnings have been issued in the Wairarapa — not including the Tararua district — and Wellington, where northwest gales are forecast to reach up to 130km/h.

Canterbury High Country is also on alert for a strong-wind warning and gusts are expected to get up to the 120km/h mark.

Aucklanders can expect a fine start to Saturday with a high of 21C. There’ll be the odd shower and northerlies from late morning and rain will develop tonight. By tomorrow there will be strong northerlies with periods of heavy rain, with a high of 19C.

Rain is forecast to persist in the City of Sails until Wednesday.

MetService has released a graph detailing exactly how bad the weather is forecast to be — with the average forecast models for tomorrow looking to be one of the worst storms since at least 2014.

Part of the cause of the storms set for the weekend is a rapidly deepening low over the Southern Ocean that will grow so large it will bring strong winds, snow and sub-zero wind chills to parts of the lower South Island.

The gales from it may spread as far north as Auckland City.

“It starts in the South Island tomorrow evening with wind and rain and then moves up the North Island during the early hours of Sunday,” Coutts said.

“The snow comes in from lateSunday into Monday morning and goes right down to sea-level in Southland. It’s the lowest we’ve forecast snow this winter.”

This weekend’s national forecast looks nearly as bad as a huge storm in May 2014, when 4500 homes lost power and massive amounts of snow fell in Queenstown.