The forecaster issued a range of road snow warnings for South Island highways as a late wintry blast works up the country.
MetService said rain in Southland and Otago this morning would spread northwards to Canterbury in the afternoon, and that snow was expected to about 200 metres parts of the South today and on Tuesday.
In an update late this morning, MetService issued a road snow warning for Dunedin's Northern Motorway (State Highway 1) to go with warnings earlier issued for the Lindis Pass (SH8), the Crown Range Road and the Milford Road (SH94), where chains should be carried after 7pm.
Further north, road snow warnings have also been issued for Arthur's, Porters (both SH73) and Lewis (SH7) passes. Snow was also forecast for the Desert Road (SH1) in the central North Island tomorrow.
MetService meteorologist Katie Hillyer said the winds in the South Island "shift to a cold and blustery southerly tonight, meaning sheltered western regions become fine tomorrow, but eastern regions are exposed to the showers and cloud that will gradually ease toward the end of the work week".
"People will feel those temperatures drop today, with maximums today and tomorrow staying in the single digits in for many. A rough start for the little lambs.”
She said that with clearer skies on the way later this week, slightly warmer afternoons but also colder mornings were on the cards.
NZ Transport Agency/Waka Kotahi earlier said snow was already falling in some places in the South, and frost and ice were likely in coming days.
The agency's system manager Mark Pinner said very frosty conditions were expected in the following days, which meant icy roads were likely.
"Our crews will be out and ready to clear snow and lay grit or a de-icing agent on icy roads," Pinner said.
"If conditions are considered bad enough, temporary speed reductions or road closures are also possible.
"We want to remind motorists to drive with care and to the conditions - including being visible, reducing speed, adjusting the travelling distance behind other motorists and avoiding sudden braking or turning movements."
Road snowfall warnings
Dunedin to Waitati Highway (SH1), for six hours from 1am-7am on Tuesday.
Forecast: Showers may fall as snow about the summit of the road early tomorrow morning, when 1cm to 2cm may accumulate.
Crown Range Road, for 15 hours from 4pm today until 7am on Tuesday.
Forecast: Snow is expected to lower to 800 metres in the morning where up to 2cm of snow may accumulate on the road about the summit until mid afternoon, with lesser amounts lower down. Further snow showers were expected tonight and early on Tuesday morning, when 1cm may accumulate at times above 400 metres.
Lindis Pass (SH8) for 13 hours from 2pm today until 3am tomorrow.
Forecast: Snow may affect the summit of the road this afternoon and again overnight. Between mid-afternoon and early evening 1-2cm of snow may accumulate at the summit, with lesser amounts down to 700 metres. Further snow is possible overnight Monday to Tuesday with less than 1cm above 600 metres accumulating.
Milford Road (SH94), for 12 hours from 4pm today until 4am tomorrow. Chains needed after 7pm.
Forecast: Snow was expected to affect the road until early afternoon with 2cm to 4cm accumulating on the road near the summit. Overnight, another 1cm to 2cm was forecast near the summit.
Porters Pass (SH73), for 14 hours from 9pm today to 11am tomorrow.
Forecast: Snow expected to affect the road this evening and tomorrow morning. Some 5cm to 10cm of snow could accumulate down to 600 metres, with lesser amounts to lower levels. Snow showers may continue into Tuesday evening, but accumulations for the road are not expected to be significant.
Arthur's Pass (SH73), for 9 hours from 1am to 10am tomorrow.
Forecast: Snow possible above 500 metres early Tuesday morning. 1cm to 2cm of snow may accumulate near the summit with lesser amounts lower down.
Lewis Pass (SH7), 17 hours from midnight today until 5pm tomorrow.
Forecast: Snow expected to develop around midnight today. Some 2cm to 4cm of snow may accumulate about the summit early tomorrow morning and lesser amounts down to 600 metres. Snow showers may continue to affect eastern parts of the road down to 300 metres through tomorrow morning and afternoon and 1cm to 2cm may accumulate.
Desert Rd (SH1), 8 hours from noon to 8pm tomorrow.
Forecast: Snow showers are expected to affect the road above 700 metres tomorrow afternoon and evening. Some 2cm to 4cm may accumulate about and south of the summit, with lesser amounts further north.
- Allied Media/RNZ
