"It will be generally fine across most of the country today with just some high cloud. After quite a cool, calm morning North Island will start gradually warming up."
The fine conditions will continue into Sunday, before a front starts to arrive from the Tasman Sea in the afternoon, first spreading cloud over the country before evening rain in western-most areas, including Taranaki and Buller.
The low is expected to bring rain and strong winds to many parts of central and northern New Zealand from later on Sunday through to Tuesday.
Rain-parched Auckland could get showers on Sunday evening.
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By Monday rain is forecast over all of the North Island, Crabtree said. Auckland is in for a decent dousing - welcome relief for the alarmingly-low dam levels.
Conditions could be severe in some areas, including northwest Nelson, and the mountain and hill country of Taranaki, Waitomo, and Taumarunui including the Whanganui headwaters, the ranges of eastern Bay of Plenty, and northern and eastern parts of Marlborough.
Crabtree said it was important people in those areas kept an eye out for any weather warnings in the coming days.
Meanwhile, a ridge of high pressure should build over the south of the South Island on Monday and Tuesday, then spread further north on Wednesday.
However, a trough may persist about the upper North Island on Wednesday, but associated severe weather is not expected at this stage.
According to WeatherWatch NZ, despite the rain being widespread the heaviest falls will be patchy.
In the upper North Island drought zones, including Auckland, current estimates show 10 to 35mm should fall in the 24 hours from Sunday morning to Monday morning.
There should be some additional rain or showers on Monday and Tuesday.
Down the country and the central, western and lower North Island may have higher totals with two days of rain on the way. Even some eastern areas may get rain into Monday and Tuesday.
Takaka and western Nelson region may see some of the highest rainfall with totals possibly approaching up to 100mm in the ranges.