Wet, windy weekend ahead
Large areas of the South Island and lower North Island will be blasted by northwest gales for the rest of today and at times tomorrow, while rain will be heavy in many western areas of the South Island.
MetService said up to 200 millimetres of rain was possible in Fiordland north of Lake Manapouri between 9am today and 3am tomorrow, while up to 250mm could fall in Westland south of Mt Cook in the 24 hours to 9am tomorrow.
In Otago, up to 200mm could fall at the Main Divide in the 18 hours to 3am tomorrow, while up to 250mm could fall at the Main Divide in Canterbury in the 21 hours to 6am tomorrow.
There would be significant spillover for the headwaters of Otago and Canterbury lakes and rivers.
"During this period, around 300mm of rain is possible in some areas," MetService said.
"People are advised that the heavy rain could cause flooding and slips. Rivers and streams may rise rapidly, including those in eastern Otago and Canterbury, where there may be little rain, but are also likely to respond to heavy rain falling in the headwaters."
Winds could reach 120kmh in Southland, and 130kmh in Canterbury, Marlborough, Wellington and Wairarapa.
The strong west to northwest flow over much of the country tomorrow should ease and turn southwest during Sunday.
Rain should also ease in most places on Sunday, MetService said.
Despite that, strong winds were possible for the east of the South Island, Wellington, Wairarapa and Central Hawke's Bay on Sunday, with heavy rain possible in the west of the South Island and the Tararua Range.
Cold southerlies should spread over the South Island on Tuesday, with some chance of significant snow below 500 metres in Fiordland, Southland and southern Otago.
Heavy rain was possible in the east of the North Island on Wednesday, along with significant snow about the Central Plateau, MetService said.
"However, there is too much uncertainty at the moment to highlight specific areas," it said.
Much of the country is expected to feel the sting of the southerlies next week.
Even in Kerikeri, the daily maximum is expected to get no higher than 11 degrees Celsius next Wednesday and Thursday.