WeatherWatch.co.nz is taking a look at the climate drivers influencing New Zealand's temperatures and rainfall.
This is not a weather forecast but an outlook covering trends and the latest on what is happening with El Niño as it continues to develop.
"As of the beginning of August El Niño is still not officially with us - but the latest update from the Bureau of Meteorology (BoM) continues to place our part of the world in an "El Niño Alert" - meaning it's arrival is imminent," says a statement from WeatherWatch.co.nz
BoM's statement issued on August 1 says El Niño development is considered "likely in the coming weeks" - and this is despite the current lack of atmospheric response to sea temperatures rising in the eastern Pacific.
There are two parts to measure El Niño - sea surface conditions at the equator and then the atmospheric response to that which links it up, says the weather organisation.
"While sea surface conditions are well above normal in the equatorial Pacific near South America (classic strong El Nino set up) the atmosphere around New Zealand and Australia is yet to fully link up.
"Climate drivers like El Niño and La Niña can take many months to form and ease - they don't develop rapidly like the weather does, so this big time frame is normal."
In the past an El Niño "Alert" lead on to an El Niño event developing around 70 per cent of the time, according to BoM research.
"In America NOAA scientists say it has already arrived as it starts to impact their weather. But not here in New Zealand or in Australia - with both Niwa and BoM saying an announcement is still in the coming weeks.
"What's making it a little messier for NZ is the fact we have a local marine heatwave still carrying on - usually El Niño brings cooler sea surface temperatures to our side of the Pacific. Not only that, but in the western equatorial Pacific it's still warmer than usual...and that's more like La Niña, El Niño's opposite.
"NZ has westerlies off and on coming up - but the easterlies are still in the mix this month too, along with northerlies. That's what we mean by being in a neutral and chaotic set-up and not yet El Niño driven."
EL NINO RECAP
Sea surface temperatures (SSTs) in the tropical Pacific are exceeding El Niño thresholds, with climate models indicating this is likely to continue at least through to the end of the year. In the atmosphere, however, wind, cloud and broad-scale pressure patterns mostly continue to reflect neutral ENSO conditions - according to BoM.
"This means the Pacific Ocean and atmosphere have yet to become fully coupled, as occurs during El Niño events. El Niño typically suppresses winter–spring rainfall in eastern Australia and northern and eastern New Zealand," says WeatherWatch.co.nz
"New Zealand remains in a neutral and therefore chaotic weather pattern - being driven mostly by high pressure zones out of Australia, but with low pressure zones or rainmakers in between these highs which are mostly affecting the southern coastal parts of Australia and then on into New Zealand."
- ClimateWatch is a monthly climate driver update powered by RuralWeather.co.nz and IBM.
3 comments
Climate change
Posted on 03-08-2023 10:59 | By Let's get real
I am very keen to more accurately understand the enormous changes that have been happening and it's becoming a case of "who do you believe"... Over recent years I have noticed increasing natural phenomena such as violent earthquakes and volcanic activities that I tend to believe are extremely relevant to other global systems. Then there is the fantastic information passed on by Mr Maunders regular articles printed here that indicate the obvious influences that the sun has on environmental issues. I tend to believe that the natural world has much more influence on the climate than mankind. What happened to the planet in the lead up to the last polarity flip I wonder...?
Let's get real
Posted on 04-08-2023 13:02 | By This Guy
Even people back in the 1900's people were aware that the industrial revolution was going to cause issues for future generations - How is it you don't think pumping billions and billions of tons of Co2 in the atmosphere for over a hundred years doesn't have an effect?
@This Guy
Posted on 05-08-2023 23:26 | By Let's get real
Population growth and not CO2. Population growth causes the increase in carbon emissions (you'll note that the terminology has changed after it was realised that CO2 is heavier that air and plants actually need it to grow) Population growth is diminishing plant material and there are now vast numbers of fossil fuel power generation plants being built because people are scared of nuclear power for stupid reasons. But that doesn't diminish my points about natural phenomena being a bigger driver than the ever increasing world population. They are now experimenting with growing food in a Laboratory for goodness sake, hydroponics, aquaculture and vertical gardening... I wonder why...? It's just easier to blame something tangible, like cars and industry, than to blame a natural phenomena and enormous population growth over the last 60 years. But maybe if you sit in the dark and ride a bike, you'll save us all.
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