Three bouts of bad weather are expected to bring strong winds to much of the country, with temperatures fluctuating wildly from day to day.
(file photo) Photo: RNZ / Rebekah Parsons-King
MetService has heavy rain warnings in place for Westland south of Otira, the headwaters of Canterbury lakes and rivers about and south of Arthur's Pass, and the headwaters of Otago lakes and rivers for Tuesday.
Some 10-15cm of snow is expected on Milford Road above 800m, with lesser amounts down to 300m. Some 3-5cm was expected in Arthur's Pass and Crown Range Road above 800m, and 1-2cm on Lindis Pass near the summit.
Meanwhile, a strong wind warning is in place for the Canterbury High Country with northwest gales, and gusts reaching 120km/h in exposed places.
National Institute of Water and Atmospheric Research (NIWA) principal forecasting scientist Chris Brandolino told Morning Report strong winds could also hit places in Southland, Fiordland and the West Coast before making their way to Wellington later in the week.
"I know Wellingtonians have a high standard for what's defined as 'windy' so the next couple days we'll call it a stiff breeze for Wellington standards... Thursday night into Friday is when the wind will be especially strong, there'll be northwesterlies ... gust over 100km/h, in some cases close to 120km/h, and that would be enough to cause some damage."
"Then we'll catch a break and then we'll see more active weather as we end the weekend and start a new week."
A separate system would also mean strong winds - though not as strong - for Auckland tomorrow.
"For Auckland, Wednesday's the day where there could be some really strong winds ... gusts down the west coast of the Auckland region on Wednesday approaching 100 clicks, and also the interior portions of the Auckland region will see winds well over 70km/h," he said.
The most unusual thing would be the swings in temperature, however.
"What you see on one day, probably not gonna get the next day," he said. "Today in ... eastern Canterbury, upper teens and 20s, and tomorrow you'll struggle to get to 12 degrees for a maximum.
"As we work ahead towards Thursday we'll see temperatures in the east of the South Island once again well into the teens, to perhaps lower 20s and that'll work its way north, and then we'll see colder temperatures replace that Friday and Saturday, then we'll do it again Sunday and Monday.
It seemed the season was the reason for the changeable weather.
"It's spring, man. More in spring, we get a lot of active weather, it's not uncommon to get very changeable weather, and with change ... oftentimes that's an opportunity for basically disruption in terms of active weather - wind and rain."
"Mother nature loves balance, her job is to create homeostasis, equilibrium, balance in the atmosphere. You got too much heat one place, not enough heat in another and as a consequence you get low pressure, you get storms.
"We're seeing the huge high over Australia, huge low to the south and east ... that's driving the wind, it's also driving the change in temperature."
MetService has warned snowfall is expected to affect many South Island roads and passes and may cause stress to livestock, with surface flooding and slips possible.