The high-pressure system bringing clear days and cold nights to New Zealand will move off the country early next week, chased by a front bringing rain and strong winds.
As the high pressure moves away to the east over Monday, this allows a strengthening northerly to spread over the country.
This is followed by the front approaching from the Tasman Sea, which is forecast to slowly move northwards over the South Island on Tuesday, then more quickly over the rest of the country on Wednesday.
MetService says there is a moderate confidence rainfall accumulations will reach warning criteria about Fiordland from late on Monday into Tuesday morning.
"On Tuesday, there is high confidence warnable amounts of rain will fall in Westland south of Otira and the headwaters of the Otago and Canterbury lakes and rivers," it says.
"Also on Tuesday, there is low confidence a heavy rain warning will be required for Westland from Otira northwards, Buller, Nelson, northern Marlborough, Southland, and coastal parts of Clutha and Dunedin. Late on Tuesday into Wednesday, there is low confidence of heavy rain about Mount Taranaki."
The front also brings a moderate risk of severe north to northwest gales in exposed parts of Fiordland, Southland, Queenstown Lakes District and the Canterbury High Country on Monday and Tuesday.
"On Tuesday, there is moderate confidence of severe northerly gales in Wellington, and low confidence of gales from the northerly quarter in exposed parts of Buller, Nelson, Marlborough, the Canterbury coast and plains and the remainder of Otago," MetService warns.
"Finally, snow is likely about inland parts of southern New Zealand on Tuesday and Wednesday. There remains uncertainly as to the snow level and how much snow will fall at this stage, but some high roads and High Country farms could be affected."
