Weather: Polar blast brings more frost, cold weekend ahead for most of NZ

Another frosty morning for much of the country with temperatures as low as -5.2C in the south. Photo / NZH

Another frosty morning for much of the country with temperatures as low as -5.2C in the south.

According to MetService, Twizel was the coldest place in the country at 7am, Christchurch was sitting on -2.2C, Timaru -1C and Methven -1C.

It was not much colder further north with Wellington sitting on 4C, Rotorua 5C, Gisborne 4C and Masterton 2C.

Bit cold this morning in #Timaru. pic.twitter.com/rK2EYxkBUG

— Leonard Craig Kendrick (🇳🇿👊) (@CraigKendricknz) July 8, 2021

But another surge of gales and polar air is on its way meaning a cold weekend is on the cards for most of the country.

According to WeatherWatch.co.nz, the low is expected to hit Southland, Otago and the lower South Island later today.

It is forecasting wind chills will drop below zero in most main centres with snow falling on the hills.

"While the snow level is generally about 300m it may go lower overnight tonight for a time," head forecaster Philip Duncan said.

Dunedin's windchill tonight is expected to be -3C at sea level.

"Snow is most likely in Southland, Otago and Central Plateau over the next 36 hours.

"This cold blast, which started on Tuesday night will finally ease on Sunday."

Following the wet and snowy weather falling tonight and Saturday morning, it will significantly increase the chances of black ice, mostly on South Island roads and highways, according to RuralWeather.co.nz.

Central Otago and northern Southland will also be bitterly cold with overnight lows down to -4C to -6C while places like Queenstown to Arrowtown will drop to -2 to -4C in some locations.

2-day snowfall accumulation from Friday to Saturday. Photo / Supplied

"The North Island's Central Plateau will be the coldest in the north with overnight lows around Waiouru, Ohakune and National Park getting down to -4C next week.

"But nearby Taupo and Rotorua are more likely to be caught up in the airflow of the northern low pressure system. Overnight lows for those two main centres gets down to about +2C to -1C," a spokesperson said.

RuralWeather.co.nz is forecasting overnight lows to dramatically drop in the South Island from Sunday night with lows of -7C to -12C in the high country.

"Places like Tekapo and Twizel and surrounding areas are most exposed to this extreme cold.

"Following the wet/snowy weather falling again tonight and Saturday morning it will significantly increase the chances of black ice, mostly on South Island roads and highways."

The cold air then moves up the South Island with snow flurries in the mountains and ranges as it heads towards the North Island, WeatherWatch.co.nz is forecasting.

2-day rainfall accumulation from Sunday to Monday. Photo / WeatherWatch.co.nz

Duncan said despite the low being north of New Zealand, the cold air brought in by the Southern Ocean southerly will linger for much of next week.

"The colder airflow will then linger in the eastern North Island from Sunday through to next Wednesday with often cloudy, showery, weather there."

It will mean a colder than average week for a number of regions.

"From the polar blast last week to the cold southerly this week lingering into next week, we're certainly into peak winter right now.

"From late June to mid-August New Zealand often experiences the depths of the winter cold in the most consistent day-after-day manner," he said.

Even the low early next week, won't likely move south enough to bring a warm change, Duncan said.

Wind gusts expected at 2pm on Friday. Photo / WeatherWatch.co.nz

"The low doesn't look too serious but with the incoming high it will generate some windy 'squash zone' weather and the consistent easterly flow will see rain accumulating in the north and east.

"This is good news for dry parts of the Far North and Northland which may get 30mm to 50mm of rain but it will come with winds gusting into gale-force for some, up to 80km/h in some exposed places."