Cold fronts bring threat of thunderstorms, hail to parts of the country

The South Island and lower North Island may be in for thunderstorms on Sunday as two cold fronts move up the country.

MetService warned two cold fronts would move across the South Island on Sunday and onto central New Zealand tonight. These fronts brought the risk of thunderstorms which were likely to bring heavy rain of 10 to 20mm/h and hail.

MetService meteorologist Peter Little said one cold front was approaching the Buller region as of midday Sunday, while another was tracking over Fiordland.

“We’re not expecting a lot of thunderstorms but you know there could be one or two as the front goes past, tomorrow it’s still fairly showery in a number of places and there’s still a thunderstorm risk with the fronts over parts of Taranaki, Kāpiti Coast, Horowhenua area,” he said.

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The forecaster said there was moderate risk of thunderstorms in Fiordland in the morning, then moving over Westland and Buller in the afternoon and evening.

The risk of thunderstorms extended from Dunedin up to south of Christchurch in the afternoon and evening, while western Tasman and Horowhenua Kāpiti Coast could be in the firing line later on Sunday.

The fronts were expected to continue moving north-eastwards today and tomorrow, Little said.

The cold fronts brought freezing temperatures in the upper atmosphere, meaning any thunderstorms that did develop could bring hail, Little said.

“There’s definitely a risk of hail, though it would be fairly small in the West, the better chance of some slightly larger hail would be if we get any thunderstorms developing about eastern Otago and near the Canterbury coast – those thunderstorms have the potential for hail up to about 15mm.”

The thunderstorm risk was expected to decrease as the cold fronts moved northwards from there, he said.

On Monday, southern parts of Wairarapa could be in for some nasty weather as a southerly change brings showers and the chance of thunderstorms.

Meanwhile, the country had a chilly start to the day on Sunday, with temperatures dropping close to zero in some regions.

The mercury dropped to just -0.3C in the North Canterbury town of Culverden on Sunday morning, while Christchurch Airport reached a frosty -0.3C.

At the top of the South Island, St. Arnaud in the Nelson lakes area got down to -1.7C and Blenheim locals were urged to rug up as temperatures hit just 1C.

Down south in Queenstown, morning showers coincided with temperatures dropping to 1C in the tourist hotspot.

Although the North Island escaped the worst of the cold on Sunday morning, the island’s east coast bore the brunt of the chilly temperatures.

Temperatures on the Desert Rd dropped to -0.9C and a weather station south of Waiouru got down to -2.2C.

In the east, Masterton and Napier hit 5.6C and 5.8C respectively, while Taupō hit 6C.