A weather system is set to reach the South Island's lower west coast on Friday afternoon before pushing north in the days that follow.
MetService has issued orange-level rain warnings for Fiordland on Friday afternoon, and for the Westland ranges and headwaters of Otago and Canterbury lakes overnight Friday. An orange wind warning covers Canterbury high country between 9am and 9pm Saturday, with gusts forecast to reach up to 130 kilometres per hour. Otago and Southland face winds up to 90 kilometres per hour.
A cold air mass is forecast to advance northward throughout Sunday and early next week, bringing heavy rainfall and possibly heavy snow. Snow could fall as low as 400 metres in the Southern Alps, with road snowfall warnings possible on mountain passes.
MetService meteorologist Brayden White said Marlborough and southern Wairarapa face the greatest rainfall risk from a slow-moving front forming over central New Zealand early next week. "The biggest area of concern is the Marlborough area, but there is a risk again that some of those places in the southern Wairarapa that have already seen quite a bit of rain from that most recent event could see a fair amount more," White said.
Heavy rain warnings remain possible for Canterbury and eastern Bay of Plenty on Monday, with severe gales forecast for the West Coast and Cook Strait the same day.
White advised drivers to exercise caution during the school holiday period. "It could be fairly windy and your car could be getting shoved around a fair bit, so just make sure you're driving to the conditions and making smart choices," he said. On the forecast snow, White said: "A great excuse to take the kids out for a snow day, but if you're planning on doing some travel, just know you may need chains or the roads may be closed for a time."
The weather system is expected to ease toward the second half of next week, though further weather systems are forecast the following week.