Heavy snow, rain and strong winds are likely to smash the South Island as a "large and complex low pressure system" heads towards New Zealand.
However, while a wintry blast will hit the country's eastern coast, there could be other areas that bask in sunshine due to the severity of the storm.
Usually bearing the brunt of any storm, the West Coast is set to be among the driest areas for the next seven days, according to Philip Duncan at weatherwatch.co.nz.
Duncan says it's still too early to specify exactly where the weather will hit, but "early indications" did show up to 40cm of heavy snow landing on the Southern Alps and Alpine Highways this weekend.
The storm as it is currently forecasted to be at noon on Saturday. Photo / weatherwatch.co.nz
Meanwhile, in the Coromandel, the king tide is to begin hitting the region tonight and area civil defence controller Garry Towler says they're bracing for big waves.
Diggers and bob cats will be at the ready to help lessen the impact of the larger-than-normal swell set to batter areas, including Whitianga.
Towler said the large swells are forecast to hang around until about Saturday but they were ready for it.
"Really, we're just going to be business as usual. Over the next few days we don't anticipate any risk to people or property."
As for the weekend's storm, Duncan said there could be between 1cm to 5cm of snow falling on the Canterbury plains, above a couple of hundred metres altitude.
The south to southwest flow will see Canterbury hardest hit by rain too, with early estimates of between 70mm and 90mm through inland areas, including Darfield.
"This rain, if it does eventuate, will be very welcome in the dry region," Duncan said.
As the North Island has milder westerlies at the end of the week - after a gusty few days - it will be the South Island's turn by Sunday, with the strong winds battering eastern Australia likely to be felt here by then.
"The low is going to bring in that southeasterly over the South Island but first it's bringing a norwester over the North Island, so the North Island won't be as cold to begin with, it will take another day or so to get into the north.
"So [system] sort of moves into the south on Saturday, definitely Sunday, and later into Sunday, Monday that colder southeasterly moves into the North Island."
The system at midday on Sunday. Photo / weatherwatch.co.nz
North Islanders won't feel the brunt as much as the southerners but Duncan said it would still be "windier and colder than what we've just had".
However, it was still early days and while it was large, it could still break off or change shape with rain or winds hitting other areas.
"It's such a big low that the middle of it might be calm but we haven't locked in which parts of the North Island will be the windiest yet."
Unsurprisingly Wellingtonians could expect a southerly blast late on Sunday before moving north towards Taranaki. As it moved further up the island it would eventually peter out, he said.
As cold and wind hits western areas, rain will hit the east coast, including the parched Hawke's Bay, who Duncan said "need as much as they can get".
"They'll get rain when it's the northwester, not much, and then when it turns southerly they'll get another burst and then showers."
Overall, Duncan said the complexity and size of the system meant it could change at any stage leading up to the late Saturday.
"It 's a complex low, it's very big, there's a lot of moving parts to it, the general theme is that there's a big southerly coming in at the end of it."
Despite the storm, MetService has South Island temperatures hovering around 10 or 11C - similar to today - although Christchurch is currently just warming up after an overnight low of 1C.
Meanwhile Aucklanders would continue to bask in sunshine until rain arrives on Saturday before they lighten to showers through Sunday and Monday, according to the MetService.
