Break in the weather for Saturday – then southerly gales, heavy rain Sunday
Between a rainy Friday and a cold windy, wet Sunday, there's some reasonable weather on Saturday to enjoy the many events held around the country.
The rain across much of the North Island on Friday, brought by a low fuelled by warm, moist air from the Tropics, meant an end to a long period of dry weather in some places.
MetService said rain in Tauranga ended a run of 36 dry days, the third longest succession of days with less than 1mm of rain in the area since records started in 1910. The city had 9mm of rain on Friday, and about the same amount again between midnight and 8am Saturday.
That's good news for the 50,000 fans going to see Kiwi pop band Six60 at Western Springs Stadium on Saturday night. MetService is forecasting showers becoming isolated during Saturday morning for the area from Northland through to Taranaki, including the Coromandel Peninsula, and the central high country.
That's also good for the Splore music and arts festival, on the Firth of Thames coast, east of Auckland. There is a chance of some rain on Sunday before the event winds up.
A mostly dry day is expected in the lower North Island, which is good for the Te Matatini Kapa Haka Festival at Westpac Stadium in downtown Wellington, and for Wings Over Wairarapa. Unfortunately, the planned New Zealand debut of a B-52 bomber is off the programme, with the plane grounded in Australia because of a maintenance issue.
An early Saturday post on the Wings Over Wairarapa Facebook page said the weather was looking "great" at the Hood Aerodrome event venue.
But MetService is expecting things to deteriorate later on Saturday, forecasting isolated showers in the evening in Wellington, Wairarapa, Marlborough and Canterbury.
On Sunday, most of the North Island is expected to get some rain, with some heavy falls forecast. It's a similar story for the south and east of the South Island, but the west is expected to be mainly fine. Cold southerly gales are expected in the east of the South Island on Sunday, spreading into the North Island.
MetService is warning of heavy rain in some eastern areas on Sunday.
The biggest risk is for the Kaikōura Coast and ranges where up to 150mm of rain could fall during Sunday, starting sometime after 1am, as an active trough moves north.
There's also a risk of heavy rain in Hawke's Bay and Wairarapa, where there's a chance of localised downpours at rates up to 40mm an hour. Heavy rain is also possible in the Canterbury foothills north of the Rakaia River.
After so much warm weather this summer, temperatures will be appreciably lower this weekend.
Christchurch got to 29 degrees Celsius on Friday, but easterlies on Saturday should keep the high down to 18C, then southerlies on Sunday will mean a maximum of around 15C.
In Wellington, winds were coming from the south or southeast on Saturday. The main impact will be a cooler night, with the overnight low expected to drop to 11C, compared to 18C overnight Friday.
With the winds swinging toward the south, Aucklanders will get some night time relief. After tossing and turning through lows of 20C in the past two nights, overnight Saturday the temperature is expected to get down to 16C, then 13C overnight Sunday and 11C overnight Monday.
Some snow is expected over the weekend, down to 1700m on the Southern Alps and 1600m in Fiordland on Saturday. On Sunday, snow could lower to 1200m in the north of the South Island.
However, the chilly spell doesn't herald the arrival of autumn.
"After this cold air goes across, there's another ridge of high-pressure building, and there will be some more sunny weather, and some warmer temperatures," the MetService's Glassey said.
"We're still in summer."