A cold front was surging through Wellington last night and is now making its way up the country, sweeping gale force southerlies over the southern and eastern North Island areas in its wake, MetService says.
Temperatures have plunged as cold Antarctic air follows close behind the front. Snow was expected down to 400m in Southland and Otago, to 300m in Canterbury and 500m in Marlborough overnight.
Yesterday a heavy snow dump and ice worries cut access to Tekapo, closing SH8 at either end of the township. Some motorists had to abandon their vehicles outside the town as the third snow fall in three weeks brought the town to a standstill.
Further north, Inglewood in Taranaki received 77mm of rain over six hours yesterday, causing major flooding on State Highway 3.
The cold blast moves north over the eastern and southern parts of the North Island today, and is expected to bring showers to most areas. Heavy rain and a strong southerly were likely to hit Wairarapa, Hawke's Bay and Gisborne early this morning.
Morning showers should clear in most places, and the sun break through in spots. The Bay of Plenty can expect a fairly dry day.
Auckland and northern Waikato could get heavier showers late afternoon and evening, clearing to a fine night ahead of a settled weekend.
Weatherwatch.co.nz said snow flurries could lower to 400m or even a dusting down to 300m for Wairarapa, and gusty cold southwesterlies would develop in the morning.
Snow flurries down to 400m are possible east of Wellington in the afternoon, with brisk, cold winds blowing from the south.
Today was expected to be cold but clear in the south, and winds would out as a ridge of high pressure moves in from the Tasman Sea. Frosts are highly likely tonight and tomorrow night in the south.
MetService meteorologist Andy Best said Mosgiel would wake to -3C tomorrow morning and -4C on Sunday. Middlemarch would have a severe frost of about -10C both days.
Although this weekend will be settled, Weatherwatch warns New Zealand is "stuck in a severe weather rut", and another round of heavy rain and snow is likely from Wednesday next week.
Road closures and warnings
Severe weather watches are in force for many parts of the country, and people travelling should check the NZ Transport Agency website for road closures before heading out.
A swathe of road snow warnings was issued for highways including the Desert and Rimutaka Hill Rds. Up to 10cm of snow was expected to fall in the Central Plateau highway from midnight last night until midnight tomorrow, and about 5cm could accumulate on the Rimutaka Hill Rd by tomorrow morning.
State highways in the south have reopened but motorists are being warned to take care as snow and ice are still causing issues on SH8 near Tekapo and SH80 to Mount Cook National Park.
Flooding has caused issues on SH1 near Timaru, on SH79 between Fairlie and Geraldine, and SH77 between Ashburton and Methven. Road users are advised to take extra care.
Flooding on SH83 between Georgetown and Black Pt was also blocking the northbound lane near Smillies Rd.
Restrictions have been lifted on the Lindis Pass (SH8) between Tarras and Twizel.
Snow is expected to continue near the MacKenzie Basin, where 15-20cm was due by midnight last night down to about 600m.