1News weather expert Daniel Corbett says Spring, which officially starts today, is arriving with a bang. He explains what we can expect in the coming days and weeks.
Spring set to be ‘rollercoaster’ – watch Dan’s outlook on TVNZ+
Buckle in again. It looks like the wild ride of weather from the Winter will continue right through the Spring.
The recent spell of drier weather in August has given us a breather from the active rainmakers of June and July.
Moving forward into Spring keep that merino layer and raincoat handy. Even though we might have a few fine and milder days there could be brief wet, windy and colder blasts to come.
What’s been going on the with weather?
Things did quieten down a bit during August with a few more fine days in the mix thanks to passing highs (anti-cyclones). This was helped by some extra warmth higher up in the atmosphere spreading down to New Zealand across Australia from the Indian Ocean.
The warm seas around the country have cooled slightly over the last several weeks but are still primed and ready to give the next rainmaker more oomph.
Warmer than normal seas
This Winter has been a bit like heading to the local buffet restaurant and grabbing a plate and loading up with a bit of everything. No single item or, in the case of the weather, one particular type of weather.
This is what we call a neutral ENSO. Neither La Nina nor El Nino. Somewhere right in the middle with many factors influencing our weather.
There’ll be some volatile weather to start with the odd Wintry blast.
Spring 2025 will see more of the variety (Enso Neutral) but there will start to become some La Nina flavour to the weather as Spring progresses.
La Nina ENSO creates cooler than normal seas in the eastern Pacific. This in turn helps grow the big high (anti-cyclone) over the eastern Pacific. This also results in the frontal storm shifting further south during the Southern Hemisphere Summer.
Think of it as being a bit like when you’re at that restaurant buffet and they run out certain items and you are just stuck with lots of the same.
La Nina likely weak and short-lived
The La Nina we will probably remember occurred over three successive Summers, with the Summer of 2022-2023 being very active and wet. This was the Summer of the Auckland Anniversary floods and Cyclone Gabrielle.
That was a strong La Nina. The early indications of this potential La Nina are that it will be weak and short-lived, with it fading away and returning to Neutral during the Summer.
One of the factors that does helps create these extreme rainfall events is when the weather systems “linger”, or in other words the upper steering winds that push the weather system “cut off” for several days.
With warmer seas and greater contrast of warm and cold in the atmosphere the tendency for this increases. Remember the extreme rainfall event across the upper South Island in late June.
So, what sort of weather can we expect for Spring?
In a nutshell a bit of everything!
The biggest thing to watch out for at first is the variety. We will get some good active weather systems in the first few weeks mixed with some passing highs.
The deep Southern Ocean and Antarctica won’t want us to forget them just yet so expect some more of the quick Wintry blasts after the most recent one.
As more warm air moves down from the tropics in October we can anticipate more fine and even warm days. Overall it should be a warm Spring.
You’ll get lots of use out of a raincoat especially in the first few weeks with overall rainfall near average. But there could be more than normal in the east and northeast as the La Nina flavour develops in the atmosphere.
This shift to La Nina later in the Spring could increase rain chances in the northeast of the country.
Enjoy the Spring! Remember to buckle in, but you’ll manage to get the BBQ out too.
‘Buckle your seat belt’ – watch Dan’s outlook on TVNZ+
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