Snow has started to settle in Southland this afternoon as the first taste of winter begins to bite.
About 10cm of snow has settled on State Highway 94 at Gorge Hill, between Mossburn and Te Anau.
Waka Kotahi said some drivers had already become stuck and required assistance.
SH94 remains passable but the transport agency said those with little experience driving in snow should avoid travel.
Chains are required on SH94 between the Hollyford turnoff and the Chasm.
Earlier, MetService updated its forecast to show Dunedin may get a dusting of snow in the hill suburbs tonight, and a heavy snow watch has been issued for inland Otago and Southland over the next two days.
Temperatures reached 20degC around the region yesterday, but meteorologist Mmathapelo Makgabutlane said today would be a total contrast, and the high for tomorrow would be in the single digits in many places around the south.
“It’ll be a very sharp change from what we’ve seen over the last couple of weeks.”
She said a strong cold west or southwest flow would cover the south later today, bringing snow as low as 300m over the southern and eastern South Island.
The snow would be particularly heavy in areas above 700m in eastern Fiordland, northern Southland and inland parts of southern Otago between 4pm today and 2am tomorrow, when accumulations may approach warning criteria of greater than 10cm in 6 hours.
She urged farmers to prepare stock for the cold front and encouraged drivers to keep an eye on the Waka Kotahi NZ Transport Agency website for warnings about adverse driving conditions and road closures.
Road snowfall warnings have been issued for the Lindis Pass (State Highway 8), the Crown Range Rd, and the Milford Road (SH94), and for alpine passes in Canterbury
Makgabutlane said the southwest flow was expected to ease over New Zealand on Friday as a ridge of high pressure spread on to the country.
A weak front embedded within the flow should then spread north over the country over the weekend, bringing calm and clear days.
Lindis Pass (SH8)
Valid: 4 hours from 10pm today to 2am tomorrow
Forecast: Snow showers are expected to develop above 600 metres this evening. Up to 2cm of snow may accumulate above 800 metres Wednesday evening into early Thursday morning.
Crown Range Road
Valid: 10 hours from 4pm today to 2am tomorrow
Forecast: Snow is expected to develop above 500 metres late this afternoon, and 3 to 6 cm of snow may accumulate above 800 metres from late Wednesday afternoon until early Thursday morning.
Milford Road (SH94)
Valid: 19 hours from 10am today to 5am tomorrow
Forecast: Snow showers above about 500 metres are expected today and early tomorrow. During Wednesday morning and early afternoon, 3 to 5 cm of snow may accumulate on the road above 700 metres and then this evening and early Thursday morning, a further 2 to 3 cm of snow may accumulate.
Lewis Pass (SH7)
Valid: 11 hours from 4pm today to 3am tomorrow
Forecast: Snow showers are possible above 700 metres late this afternoon and evening. 2 to 5 cm of snow may accumulate on the road above 800 metres from late Wednesday afternoon until early Thursday morning.
Arthur’s Pass (SH73)
Valid: 6 hours from 4pm today to 10pm today
Forecast: Snow showers are possible above 700 metres late this afternoon and evening. 1 to 2 cm of snow may accumulate on the road near the summit late Wednesday afternoon and in the evening.
Porters Pass (SH73)
Valid: 6 hours from 1am tomorrow to 7am tomorrow
Forecast: Snow showers are expected above 600 metres from early Thursday morning. During Thursday morning, 1 to 3 cm of snow may accumulate on the road above 800 metres.
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