A polar blast is set to sweep across New Zealand with weather forecasters saying there could be snow next week, plunging a warmer-than-usual South Island back into the depths of winter.
The rest of this week is expected to be unseasonably warm with temperatures rising “well above average” for this time of year - but that will change thanks to two weather systems.
Niwa says a slow-moving low-pressure system is likely to develop near New Zealand, while a cold high-pressure system could build from the south.
“This pattern looks potentially conducive to snow,” Niwa says.
Long-range pressure patterns: low pressure looming next week...
— NIWA Weather (@NiwaWeather) July 23, 2024
🔵 Next week, slow-moving low pressure will likely develop near the country
🔴 Around the same time, a cold high pressure system may build from the south
This pattern looks potentially conducive to snow ❄️ pic.twitter.com/SpTGgMc9nt
Private forecaster WeatherWatch is also predicting a possible “winter blast” from about Tuesday.
Forecaster Philip Duncan said a blast of cold air was expected to move up from the Southern Ocean, but it was uncertain whether it would hit New Zealand.
Although the cold blast couldn’t be locked in, it was important to give farmers advanced warning, especially as they moved into lambing season.
MetService forecaster Mmathapelo Makgabutlane said next week would be a stark contrast to the warm coming days.
“Temperatures are forecast to be higher than average for this time of year, especially in the South Island, during the next two days,” she said.
“But next week we could see cooler temperatures and possible snowfall in those inland areas, especially in the central North Island.”
📺🌡️🌤️❄️#VIDEO: Winter blast possible next week in #NewZealand, but warmer before then https://t.co/LiRUFK9ve2
— WeatherWatch.co.nz (@WeatherWatchNZ) July 23, 2024
She said the polar blast would be caused by a low-pressure system drawing colder air from the south.
In its severe weather outlook MetService said the cold southerlies could bring snow to relatively low levels over the South Island, possibly affecting many roads.
Much of the country will have woken to a wintry chill this morning following a dry, clear night, with temperatures still well below zero in the central South Island.
But over the course of today, those clear, sunny skies should warm things up - except in the west where cloud could bring some rain to coastal areas, according to MetService.
Early showers were expected in Auckland but that would turn to “better, brighter weather” once the cloud cleared away in the afternoon, with a high of about 16C today and a low of 11C, MetService meteorologist John Law said.
Wellington could expect a high of 13C and a low of 8C, while Nelson, Marlborough and Canterbury would all get plenty of sunshine. Highs in those South Island regions were expected to hit 15C while lows would be around 1-2C.
As the week progresses a northwesterly flow associated with a high-pressure system from Australia is expected to bring warmer air to the country, boosting temperatures into the high teens during the daytime and cutting the chance of frosts.
In the South Island, temperatures could be well above average for this time of year by Friday, with potential for an added 7C in the far South, according to MetService.
Plenty of sunshine in South Island places that haven't seen much over the past few weeks🌤️
— MetService (@MetService) July 23, 2024
From tomorrow, temps climb above average for the time of year, possibly reaching 17°C in parts of Southland, Otago and Canterbury on Friday🌡️ pic.twitter.com/pk2yIiU5f6