Temperatures plummet in eastern, inland South Island

Thursday, 6 June 2019

A cold front continues to move up New Zealand on Thursday.

Temperatures dropped below freezing in eastern and inland areas of the South Island overnight, with Christchurch getting below -3 degrees Celsius and Timaru below -4C.

In contrast the north was comparatively warm and windy, and there's a chance of gales in Auckland by evening.

Early on Thursday, NZ Transport Agency was warning of ice in Canterbury on State Highway 79 from Geraldine to Fairlie, continuing on SH2 from Fairlie to Twizel.

Further south in Otago, drivers were being urged to take care because of ice on SH87 from Outram to Kyeburn.

**READ MORE:

Lake Tekapo got down to -7C before 6.45am on Thursday.

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By 6.45am Thursday, the temperature in Christchurch had dropped to -3.1C , MetService meteorologist Amy Rossiter said.

MetService data showed Wellington still above 4C, but Paraparaumu did get down to 1C. Auckland was considerably warmer around 12C shortly before sunrise, with brisk southwesterlies.

The stormy weather that damaged homes in the Far North on Wednesday, has moved away. In its wake, temperatures plummeted in eastern and inland areas of the South Island.

Rossiter said the coldest places were under a cool air mass and had clear skies and light winds. Frosts were possible in many of the places that dropped down to around freezing.

Lake Tekapo got down to -7C before 6.45am, Pukaki to -6C, Timaru -4.3C, Alexandra -2.5C, Blenheim -2C, Nelson Airport 0.7C and St Arnaud -4.4C. In the North Island, Tongariro in the Central Plateau was down to -4C.

Early Thursday Queenstown Lakes District Council was warning of black ice on roads across the district, and said light snow was falling on the Crown Range.

MetService expects the temperature in Christchurch to reach 13C, with winds swinging to the north. There's a chance of an afternoon shower.

Auckland is expected to get to 15C, with a few showers, rain from evening, strong westerlies and gales in exposed places from evening.

Wellington is forecast to have a fine morning, then increasing cloud in the afternoon with strengthening northerlies, and rain possible by early evening. The temperature is expected to get up to 14C.

The east of the North Island from Bay of Plenty to Wairarapa is forecast to be mainly fine. The west from Waikato to Wellington, and including Coromandel Peninsula, is expected to be fine for a time, with showers from afternoon, rain this evening, with possible thunderstorms.

The top of the South Island should be mainly fine, with brief rain late. Canterbury should be mainly fine, while the lower South Island is expected to have showers, some of which could be heavy with hail, and snow to 600 metres. Rain is forecast for the West Coast.

Meanwhile, Niwa meteorologist Chris Brandolino has questioned whether the event that caused damage in the Far North on Wednesday was a tornado.

He told The AM Show it was probably a microburst, straight line winds - described as an intense small-scale downdraft produced by a thunderstorm or rain shower.

'I don't think it was (a tornado), personally. You'd have to look at the damage and see how the damage is kind of laid out.

'Looking at the way the atmosphere was structured, it's unlikely it was,' said Brandolino.

'In order for a tornado to occur, you have to have a thunderstorm … and the air has to spin, or rotate, and for that to happen the wind changes direction with height.

'That shear creates the spin necessary for the air to rotate in a tornado.' Yesterday the winds were coming from the same direction throughout the vertical.

'It means basically the wind didn't change direction with height, which means there probably wasn't any spin.'

But he pointed out: 'Damage is damage, this is an academic question.'