Heavy snow warnings for parts of South

The heaviest snow was expected above 100m in Southland, Clutha and southern Fiordland. Photo / Supplied

Heavy snow warnings have been issued for parts of the South as a wintry blast makes its way up the country.

In an update this afternoon, MetService said an active front, followed by "a very cold southwest change", was forecast to move north across the South Island tonight and tomorrow, bringing snow to low levels.

A Heavy Snow Warning is in force for Southland, Clutha & southern Fiordland down to 100 metres beginning this evening - this may disrupt travel, damage trees & powerlines and stress livestock. Lesser amounts of snow are expected to sea level. Details: https://t.co/Sd5C6lrsSL ^CRN pic.twitter.com/8V3CsrRAuz

— MetService (@MetService) August 3, 2019

The heaviest snow was expected above 100m in Southland, Clutha and southern Fiordland, and a heavy snow warning was in force for these areas.

The forecaster said 25cm or more of snow could accumulate above 400m in these areas, and 15 to 20cm of snow above 100m.

A heavy snow watch was in place for southern parts of Central Otago, the Southern Lakes area and the parts of Fiordland not covered by the warning.

Southland and Otago farmers should be wary of the "brutal wind chill" that could prove dangerous to newborn lambs and calves by pushing localised temperatures well below zero, WeatherWatch head analyst Philip Duncan said.

As well, a brief period of heavy rain was expected in Westland, where a heavy rain watch is in place.

As at 1.15pm on Saturday only one southern highway had been affected - State Highway 94, the Milford Road, was closed owing to snow and would remain closed overnight.

Road snowfall warnings had been issued for the Lindis Pass, Crown Range Road, Arthur's Pass, Lewis Pass and Porters Pass in the South Island, and the Desert Road, and Remutaka Hill Road in the North Island.

The wintry blast was expected to bring some very cold nights for parts of the South, with temperatures as low as -6degC in some places.