The frost in some parts of the country early Tuesday was a foretaste of the incoming cold spell that could cause one of the coldest October nights on record in many places.
In several regions, including Canterbury, temperatures dropped below 3C early Tuesday, MetService meteorologist Larissa Marintchenko said.
Tuesday around 7am MetService showed temperatures of 0.7C in Timaru, -0.9C in Queenstown, 1.1C in Gore, 2.5C (feels like -2C) in Christchurch, 5.2C in Wellington, 1C in Masterton, – 1C (feels like -6C) in Waiouru and 12.2C in Auckland.
While Auckland was warmer than most of the rest of the country, dropping slightly further to 11.5C at 8am, that was still around 3C cooler than the same time on Monday.
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The coldest temperatures are expected to reach the city by the end of the week, with highs of just 13°C on Thursday and minimums of 6°C in the early morning on Friday and Saturday.
Peter Meecham / Stuff
Snow in Springfield, inland Canterbury, in August. An unusual cold spell in the coming days could bring more snow to much of the South Island and lower North Island.
The cold snap would be felt in the south from Tuesday evening, following the arrival of a front expected to reach southern Fiordland around noon, Marintchenko said.
MetService predicts snow could drop to 200 meters in the south on Tuesday night. It could fall as far as 200 meters in the north of the South Island on Wednesday and south to sea level from Canterbury.
On the North Island, snow could drop to 200 meters in Wellington on Wednesday evening and 500 meters in Manawatu.
MetService warns of a chance that the “blaze of intense cold” could bring heavy snowfalls of more than 400 meters overnight, or more than 600 meters in the Deep South, to much of the eastern part of the South Island.
Christchurch is expected to have a lovely Tuesday after the frosty start, with a high of 20C. That all changes with a southerly turn of the night, and daytime highs of just 10C are expected on Wednesday and Thursday, with an early Thursday low of -1C.
MetService predicts temperatures will drop to -3C in Alexandra early Thursday.
South winds are expected to arrive in Wellington late in the morning on Wednesday, with snow possible up to 200 meters from the evening, with temperatures dropping to 2 degrees on Thursday – which would equal the second lowest temperature in October – and only later in the day will be 8 degrees.
MetService metrologist Angus Hines described the sky as “taking a direct line from the Antarctic Ice Sheet to the South Island,” with strong winds, snow and bitterly cold temperatures.
Those conditions can put pressure on livestock, while: frost can damage newly planted crops. There was also a chance of waves of seven meters around coastal parts of Southland on Wednesday night.
Many roads in the South Island are likely to be affected and possibly closed, as well as some roads across the lower and central North Island.
Niwa forecaster Chris Brandolino predicted there could be “snowflakes” in Wellington on Thursday morning – likely in the hilly suburbs, but possibly at sea level.
MetService forecast record-breaking lows for some parts of the country that day. Masterton, for example, is looking at a high of 7C on Thursday – the lowest ever recorded in October is 8.4C. Invercargill is forecast to have a high of 6°C, the lowest record for the month is 5.8°C.
NIWA/delivered
A Niwa image shows a burst of cold air from Antarctica pulling up Aotearoa and covering the entire country on Thursday.
Blenheim is forecast to hit a low of -2C, the equal fourth coldest temperature in October. It would have to exceed that projection by just half a degree to become the third-coldest October day.
Even areas that don’t get snow will notice a drop in temperature. Hamilton started the week at 18°C but was set to drop to a high of 12°C on Thursday, with a sub-zero minimum overnight.
It was previously reported that no snow had fallen in Christchurch in October for over 50 years – However, MetService went back on that statement and clarified that the data was incomplete for two decades.
“It is certainly very unusual. It’s possible it happened in those incomplete years, but it hasn’t happened much,” Hines said.
Conditions were expected to ease on Friday, giving way to a sunny weekend for most parts of the country.
“Even as the rainy and snowy weather clears up, nighttime temperatures will still be very cold.”