Summer time forming La Nina possibly coming to Australia

Showing all posts tagged: environment

Summer time forming La Nina possibly coming to Australia

8 January 2025

Your average La Niña forms in winter, peaks in late spring, then gradually weakens through summer. However, the current edition has not played by the rule book — for only the second time in 75 years, its onset has arrived in the middle of summer.

This is something I’ve been wondering about. Over the summer months especially, I keep a close eye on the ten-day weather forecast. I’m looking out for upcoming days where temperatures are expected to exceed thirty-degrees Celsius. This because we do not have air-conditioning in either of the places we stay at. So we plan we be elsewhere, where possible, on super warm days.

But, in scanning the ten day forecast for our part of the world, there is — as of when I write this — not a single day expected to reach thirty-degrees. The nearest is twenty-eight degrees. Weird, considering January is the warmest month of the year where we are. A surprise La Niña event, kind of, explains the generally lower temperatures.

To be clear though, La Niña, and El Niño weather events do not really influence temperature: they are more indicators of rainfall levels in the northern and eastern regions of Australia. Higher in the case of La Niña, lower for El Niño. But, higher rainfall usually means more cloud cover, which will in part moderate temperatures.

I’m all for not-so-warm summers. Temperatures in the high-twenties aren’t too bad. And providing the dewpoint level stays below twenty degrees, humidity levels aren’t too oppressive either. But I’m not so sure about the accompanying rains, which can result in extreme flooding in some areas.

A La Niña weather event is yet to be officially declared, while the Australian Bureau of Meteorology has moved away making such announcements (probably because people like me write blog posts like this), so we’ll have to wait and see. La Niña, and El Niño weather events however are one of sometimes several concurrent phenomena that influence weather across Australia, meaning certain sorts of weather cannot always be attributed to one particular event.

Snow and heatwaves: this is Christmas in Australia

23 December 2024

Weather that is fine and not too warm seems to the Christmas Day weather forecast for most of Australia. But the days either side will be a different matter, writes Tom Saunders for the ABC:

The tumultuous week of variability will commence with a wintry Monday for the south-east, even cold enough for brief snow on the Alps, followed just days later by a blast of hot northerly winds and potential catastrophic fire danger.

Presently, day time high temperatures on this part of the east coast are forecast to be relatively mild. With the exception of Friday when the mercury is predicted to reach thirty-six degrees Celsius. I think we’ll be spending most of that day deep in the shade somewhere.

The W3C launches the Sustainable Web Interest Group

20 November 2024

The World Wide Consortium (W3C) has the emissions created by the internet in its sights… who knew just high web caused emissions were?

The mission of the Sustainable Web Interest Group is to improve digital sustainability so that the Web works better for all people and the planet. The digital industry is responsible for 2-5% of global emissions, more than the aviation industry. If the Internet were a country it would be one of the top five polluters. The amount of water, energy, and minerals required increases annually, often putting the burden on developing economies.

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environment, technology, trends

Weird winter weather points to yet more unstable weather

5 September 2024

Mick Tsikas, writing for The Conversation:

The severe weather rounds out a weird winter across Australia. The nation’s hottest ever winter temperature was recorded when Yampi Sound in Western Australia reached 41.6C on Tuesday. Elsewhere across Australia, winter temperatures have been way above average.

41.6°C? It doesn’t even get that hot in summer, at least where we are on the east coast of Australia. Well, hardly ever. There have been one or two days when highs have pushed into the forties, but that’s usually at the height of summer, and still, is rare.

There’s been some strong winds recently. But the trade winds are common around this time of year, particularly August. The warm weather experienced in parts of Australia last week — in what was still winter — is definitely unusual though. I looked up the Southern Annular Mode (SAM), and found the value had been neutral in second half of August. The SAM is a metric of how close cold weather fronts come to the southern part of the Australian landmass.

A negative SAM value means they reach quite some way inland. Cold fronts bring rain and cooler weather. With SAM values being neutral or positive though, these fronts have not been coming through, which may partly explain why it was so warm. But I think climate change, of course, is the remainder, or most, of the reason.

On one day, temperatures almost reached 30°C during this late winter heatwave, in our part of the world. I truly dread to think what summer will bring…

Is the Australian winter 2024 colder than normal?

5 August 2024

It depends how you define normal. Winter this year, or certainly in July, and absolutely since the recent Sudden Stratospheric Warming event, has felt distinctly chillier. But the bad news is, no this winter, when compared to the long term average, isn’t all that much cooler than “normal”.

Despite the relatively cool conditions, most capitals have still recorded temperatures comfortably above the long-term average, and all except for Melbourne and Adelaide were colder in 2022.

2022 seems a long time ago, as I don’t recall the winter of 2022 feeling cooler than this year. The thing is though, we’ve become accustomed to warmer winters, because you know why, so when a normal winter comes along, or one that is closer to statistically normal, it feels colder.

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climate, environment, weather

Sudden Stratospheric Warming is bringing weird weather to parts of Australia

29 July 2024

El Niño and La Niña are global metrological events most people are probably familiar with. In Australia, the influence of one or other seems more pronounced over the summer months. El Niño marks periods when ocean temperatures in parts of the Pacific Ocean rise by a certain amount, while La Niña events refer to occasions when these temperatures fall by a certain amount.

While ocean temperatures may affect how many people decide to go for a swim, depending how warm or cool the water is, these variations in ocean temperatures can have a significant, and far reaching, impact on the weather. For instance, parts of Australia may experience higher than normal temperatures during an El Niño event. La Niña’s on the other hand, may instead result in below average temperatures in the same regions.

But El Niño and La Niña are not the only metrological phenomena that influence weather and climate in Australia. The Southern Annular Mode (SAM) is another. The SAM is an indicator of westerly wind belts, and their proximity to the southern coast of Australia. A negative SAM for instance, sees these westerly wind belts, and their associated rain fronts, come much closer to southern Australia, bringing higher rainfall with them.

Then there’s the Indian Ocean Dipole (IOD), sometimes known as the Indian Niño, an indicator of temperature differences between the eastern and western regions of the Indian Ocean. A positive IOD reading can result in periods of low rain fall and drought, particularly in southeast Australia, while negative readings bring higher rainfall to effected regions.

But in trying to determine how the weather may play out over the coming months, an eye should also be kept on Sudden Stratospheric Warming (SSW) events, of which one occurred a few weeks ago, albeit thousands of kilometres from Australia. SSW, as the name suggests, refers to temperature increases in the stratosphere, a layer of the Earth’s atmosphere. The stratosphere is situated anywhere from ten to twenty kilometre’s above the planet’s surface. Higher in equatorial regions; lower near the poles.

But SSW events, which usually occur in the northern hemisphere, can see temperatures rise markedly, generally in the order of about twenty-five degrees Celsius. However, the recent SSW event, over Antarctica — which, in July especially, is unusual to begin with — saw temperature rise by about fifty-degrees Celsius. Fifty-degrees. Remember though, this happened some twenty kilometres above Antarctica, and not on the ground.

One can only imagine the impact of a snap surface temperature increase of fifty degrees in Antarctica, or anywhere for that matter, were that ever to happen. That’s not to say nothing at all, weather wise, will happen though. The previous time a SSW event occurred over Antarctica was in September 2019, resulting in warm, dry weather, across much of Australia in the months that followed. Coupled with an extended period of drought, the event precipitated the tragic Black Summer bush fires of 2019 and 2020.

At this stage meteorologists anticipate more westerly winds for southern parts of Australia over the coming weeks. A negative SAM index reading, then? This has already resulted in heavy snow in some places, but temperatures nudging past twenty-degrees Celsius on parts of the southeast coast, unusual for the middle of winter. As the SSW event occurred in July, and large parts of Australia have been drought-free for some time, it is expected, hopefully, there will not be a repeat of the widespread bush fires of four or five years ago.

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climate, environment, weather

Five-thousand kilometre long cloud-band across Australia

3 June 2024

The Daily Aus (TDA), Friday, 31 May 2024:

Rain is forecast across 90% of the country over the coming days as a 5,000km ‘cloudband’ makes its way from WA‘s north to south-east Australia.

According to the Bureau of Meteorology (BOM), a ‘northwest cloudband’ is an extensive layer of air and moisture from over the Indian Ocean that can bring widespread rain to much of the country.

The cloud-band was not only extremely long, and also full to brimming with moisture. While rainfall remained constant throughout Saturday, there were some decidedly heavy downpours at times. These invariably came along just as we’d parked the car, and needed to cross a street to shelter, or while outside at some exposed mid-point between buildings.

We stopped at a cafe, a nice place, located in what was once a small warehouse, with an open ceiling with a corrugated iron roof. But we could barely hear ourselves speak at times, though during some of the showers, so heavy were they.

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climate, environment, weather

Weather forecasting has improved, sadly weather apps remain oddly deficient

20 March 2024

Four day weather forecasts are now as accurate as one day forecasts from thirty years ago. That’s good news. Access to accurate weather information is perhaps more vital than many of us can appreciate.

Weather forecasting has come a long way. In 650 B.C. the Babylonians would try to predict weather patterns based on cloud patterns and movements. Three centuries later, Aristotle wrote Meteorologica, discussing how phenomena such as rain, hail, hurricanes, and lightning formed. Much of it turned out to be wrong, but it represents one of the first attempts to explain how the weather works in detail.

But more of this data needs to be ported through to the weather apps on our smartphones. I don’t know if it’s me, but the number of times I’m caught outside somewhere, in what I call “off-app” rain — that is, where no rain whatsoever is predicted for hours, if not days — seems to be increasing.

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climate, environment, weather

September temperatures gobsmackingly bananas say climate scientist

6 October 2023

American climate scientist Zeke Hausfather has described global temperatures in September 2023 as gobsmackingly bananas.

This month was, in my professional opinion as a climate scientist — absolutely gobsmackingly bananas. JRA-55 beat the prior monthly record by over 0.5C, and was around 1.8C warmer than preindustrial levels.

See also the daily temperature anomalies heatmap for 2023, where September, to use Hausfather’s words again, “stands out like a sore thumb.”

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climate change, environment

Poison ivy to bloom, become more toxic, thanks to global warming

22 September 2023

Poison ivy, a noxious plant often found in North America, and parts of Asia, could become more common place as global warming creates an environment conducive to its growth.

Poison ivy is poised to be one of the big winners in this global, human-caused phenomenon. Scientists expect the dreaded three-leafed vine will take full advantage of warmer temperatures and rising levels of carbon dioxide in the atmosphere to grow faster and bigger — and become even more toxic.

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