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- Mother Nature's La Niña Hangover!
The warm Summer and our warm and dry Autumn has been largely a result of the persistent La Niña across the Pacific Ocean. This La Niña has been quite unique because instead of fading away during the transition season (Autumn/Spring) it actually strengthened the cold SST ( sea surface temperature) signal across the central Pacific to the coldest levels in a May period since the 1950s! So what is going on? Does Mother Nature have a La Nina Hangover that she just can't seem to shake off. First of all, what is La Niña? Check out my video explainer on La Niña. In a nutshell it is cooler than normal seas across the Eastern Equatorial Pacific. In addition, seas are warmer than normal further West. Trade winds across the equator that blow from East to West are stronger than normal. These subtle changes have a big effect on global weather. I like to think of La Niña as a big high pressure machine that fuel injects passing highs and also causes their tracks around the globe move further South (or North in the Northern Hemisphere) compared to their mean position. So what's the hold-up? Why won't La Niña just fade away? Wave motions in the Pacific Ocean as well as motions in the atmosphere above are keeping the La Niña machine going (for the time being) and it has even lingered longer than some of the seasonal climate models had predicted months ago. The current projections are still a bit mixed - with some models saying the La Niña will fade to neutral (neither La Niña or El Nino) but others are keeping La Niña in place for perhaps another 6 months or so. Another warm Winter for New Zealand ? Yes, quite possibly, especially with the lingering effects of the marine heat wave in the surrounding seas. This warmer than normal air will help to temper any of the Antarctic blasts that head our way in the short term. One thing worth pointing out with the lingering La Niña is to watch out for a few surprises from the Southern Ocean...... The squeeze zone where the bigger anticyclones meet the seasonal depressions from the South can at times bring some active spells of rain, gales and even snow. It can't be warm all the time!
- La Niña - What is it?
An easy to understand explainer on what it is and how it affects our weather.
- Why is the weather stuck?
This week the weather across New Zealand will be like one of those hurry up and wait moments. That's because the atmosphere is in a giant go-slow. It all starts with the big high that drifted east of New Zealand at the start of the long weekend. It is in no hurry to move. Think of it as a big water buffalo! This week’s unsettled weather pattern will take it's time to go away and changes will be slow to come. So why has the weather been putting on a go-slow with this slow moving blocking high? It has to do with the abundant warm air in the mid-levels of the atmosphere spilling down from it's source region in the tropics north of New Zealand and back westwards to Tropical Australia. Have a look at the 500hpa map for early this week. All the yellow and orange is warmer air. As this warm air (yellow and orange) spreads down from the tropics it engulfs the incoming blob of colder air ( blue and green) from the southern Ocean. It in turn chokes off the approaching front and the low subsequently pin-wheels in place with no where to go. In the breaks between the highs there are wet zones or atmospheric rivers. At the centre of the upper ridges the weather stays dry and settled. At the moment New Zealand is in the wet zone of this flow.
- Cop 26 – What is all about?
You will probably hear the words COP26 quite a lot over the coming weeks. COP 26 is the Conference of Parties to the UN Framework Convention on Climate Change. This forum will hopefully have a major impact on how the global population plans and prepares to tackle climate change in the coming years. This conference is the first time that parties are expected to commit to further reduce carbon emissions since COP21 (Paris Agreement). This is NOW the critical time to come up with a plan of action because most of the recent climate projections (IPCC) have the planet reaching the tipping point within the next 5-8 years. The rapid acceleration of planetary warming, largely due to the” runaway train“ of globalisation has accelerated the temperature rise at a frightening pace. Several years ago the average person believed climate change would happen sometime in the distant future- maybe not even in their lifetime. However, with the recent stream of catastrophic and often unprecedented extreme weather events, everyone needs to understand that those extremes that HAD been forecasted are upon us NOW! As a young man studying for my meteorology degree over 30 years ago I was taught about global warming and it’s impact on our future. Frighteningly, now I see those predicted catastrophes happening in the present day. I have been privileged to have worked and forecasted around the world and in that time I see that the daily weather maps and forecasting criteria have changed and continue to change dramatically as this extreme planetary warming really starts to bite. Sadly the COP26 forum will not be a” flick of the switch” game changer. Even if all the World Leaders were to immediately agree to drastic cuts to carbon emissions, global warming and deadly weather events will still continue in the years to come. Any reductions will take years to see results. Can we look forward to a positive outcome to COP26? The planet’s future and our future depend on it. More importantly, it is essential that the citizens of our planet learn adaptability and ultimately survivability as our planet continues to change in the years to come. Image credit npr.org
- Climate change - a easy way to understand it.
These days you hear the terms Climate change and Global Warming quite a bit in everyday conversation. What do they actually mean? Here is a way to understand it all. Climate change and Global warming can be explained in varying layers of complex language. For most people though it is better to understand what they are and how they will relate to them in the coming months and years. Watch the easy explainer that even the younger audience can understand. More comiong soon... More coming soon...
- A change in the seasons
Some active Spring weather this week with severe gales and heavy rain. There could even be some snow down south. A bit of everything thrown into the weather mixing bowl! Spring can always be full of surprises on the weather front. This is down mainly to the dramatic contrasts in temperatures across the globe over relatively short distances. This temperature contrast produces a gradient, or difference, which in turn leads to wind. There is usally plenty of that to go around during Spring. Check out the video. There is plenty more active Spring weather on the way too! More coming soon... More coming soon..
- More extremes this week across the globe
An active and very wobbly jet stream will help bring about some big extremes in temperature this week. There could be further significant rain to parts of the globe too. More coming soon... More coming soon.. More coming soon...