On Monday and Tuesday, strong and very cold westerlies were forecast to bring snow showers to quite low levels over southern New Zealand, MetService said.
A heavy snow watch is in place for the Milford Road (State Highway 94) with snow showers from this morning, and up to 20cm of snow forecast near the Homer Tunnel from tonight until Tuesday.
Waka Kotahi/ NZ Transport Agency advised that the highway would close from 4.30pm today.
"Heavy snow is predicted into tomorrow, a further road closure on Tuesday is possible".
MetService this morning issued a number of road snowfall warnings for other alpine roads and the Crown Range, linking Queenstown and Wanaka.
Light snow showers were forecast for the Crown Range and the Lindis Pass (SH8) from late on Monday morning, while snow showers were also likely for the Lewis, Arthur's and Porters passes from Tuesday morning.
On the West Coast, a heavy rain watch is in place for Westland, north of Otira, and Buller from 9am until 3pm today. Rainfall amounts may approach warning criteria, especially about the ranges.
MetService said the cold front and rain were expected to move north over New Zealand on Thursday and early Friday. A strong northwest flow precedes the front, and a colder southwest flow follows it.
On Saturday, another cold front was expected for the southern part of the South Island.
Snow for alpine roads
Milford Road (SH94)
Period: from 11am on Monday until 5pm on Tuesday
Expect 2cm to 4cm of snow to settle near Homer Tunnel, with lesser amounts down to 700 metres, on Monday morning and afternoon. More snow was expected from Monday night until Tuesday afternoon, and another 10cm to 20cm of snow is expected near the Tunnel, with lesser amounts to 600 metres. Light snow showers were possible on Tuesday night.
Crown Range Road
Period: from 1pm on Monday until 5pm on Tuesday
Light snow showers are possible above 800 metres during Monday afternoon, and above 700 metres from late on Tuesday morning until the afternoon. Little snow (if any) expected to settle on the road.
Lindis Pass (SH8)
Period: from 2pm until 5pm on Monday
Light snow showers are possible near the summit during the afternoon, but little snow (if any) expected to settle on the road.
Arthur's Pass (SH73)
Period: from 9am until 6pm on Tuesday
Snow showers expected in the morning and afternoon. Expect 2cm to 3cm to settle on the road near the summit.
Porters Pass (SH73)
Period: from 9am until 6pm on Tuesday
Snow showers are expected in the morning and afternoon. Expect 1cm to 2cm to settle on the road near the summit.
Lewis Pass (SH7)
Period: from 10am until 7pm Tuesday
Snow showers possible from Tuesday morning to early evening, and 1cm to 2 cm of snow may settle on the road near the summit.
