'Tropospheric polar vortex' to bring cold snap around NZ

Source: 1News

MetService say "an intense cold outbreak is expected" later this week, forecasting its impacts will be felt around the country.

Early morning frost (file photo).

It comes after MetService meteorologist Luis Fernandes warned last week that "the turbulent spring weather isn't done with us yet", urging Kiwis to "keep those blankets on hand".

And NIWA has explained that "a lobe of the tropospheric polar vortex will brush Aotearoa New Zealand from Wednesday into Thursday", tweeting "that's a technical way of saying it's going to be very unusually cold and snowy for October".

"From the belly of the polar region, this surge of cold air will, for a couple of days, make it feel like mid-winter.

"First stop: Southland around midday Tuesday."

MetService has warned that the unseasonable "bitterly cold temperatures" could bring stress to livestock and damage crops, as well as snow in places.

"While widespread warning amounts of snow are unlikely there is a high probability that many South Island roads will be affected and some roads over the lower and central North Island," the forecaster said.

"People are advised to proceed with care and keep up to date with the latest MetService forecasts and advice from the NZTA since disruptions to traffic are likely."

A heavy snow watch is in place for Marlborough south of Clarence River, Canterbury, Otago, Southland and Fiordland from 11pm tonight to midday on Thursday. Strong winds are on the cards for parts of the country as well.

"There is a low confidence of severe southwesterly gales for the Banks Peninsula, Wellington and the far south of Wairarapa late Wednesday and during Thursday," MetService said.

"On Thursday there is a low confidence in severe southwesterly gales along the east coast of Wairarapa and for coastal Hawke's Bay and Gisborne."

A 'low confidence' means a 20% chance of the weather event happening.

"It's a good day to dig out those extra layers and get ready for some colder temperatures later in the week," the forecaster tweeted.