Sudden Stratospheric Warming is bringing weird weather to parts of Australia

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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.

El Nino weather event formally declared for Australia

21 September 2023

Australia is officially in the grip of an El Niño weather event. This means affected areas can expect higher than normal temperatures, and reduced rainfall. The Australian Bureau of Meteorology announcement on Tuesday confirmed what many people had suspected for some time.

The Bureau of Meteorology has formally declared an El Niño weather event, meaning one is underway for the first time in eight years. The major climate event impacts the weather patterns of 60 per cent of the globe, with Australia particularly vulnerable to its impacts.

That the declaration was made during the midst of a spring/pre spring equinox heatwave is all the more concerning. After parts of the northern hemisphere experienced a horror summer this year, with record high temperatures, and massive bushfires, some people will be dreading summer in the southern hemisphere.

Once air conditioning was not needed during summers in Cairo, Egypt

20 September 2023

American journalist and cartoonist Malaka Gharib used to visit her father in Cairo, Egypt, during the summer school holidays, in the mid-nineties. It was hot, as anyone who’s been to Egypt in June or July (yours truly) could tell you.

Like many Egyptians though, her father’s home did not then have air conditioning. It was certainly warm, but somehow everyone managed. Thirty years later, Gharib wonders how Cairo residents get by when climate change is slowly pushing up temperatures, in a comic strip she drew.

While the use of air conditioning has become more widespread in Cairo, experts warn it alone is not a long term solution to the ever warmer summers parts of Egypt are presently experiencing. In some cases their operation can exasperate the problem, by placing stress on the power grid, and upping local temperatures through the heat the units themselves expend.

Parts of Australia may see heatwaves before the spring equinox

11 September 2023

The ten-day weather forecast for some parts of NSW are currently predicting several days with maximum temperatures in the vicinity of thirty degrees centigrade. This, at the moment, for Saturday and Sunday, 16 and 17 September, and Tuesday 19 September. These temperature ranges come close to the official definition of a heatwave:

A heatwave occurs when the maximum and the minimum temperatures are unusually hot over a three-day period in a specific location. This is considered in relation to the local climate and past weather at that place.

Such a forecast may not be entirely surprising if not for the fact Australia is only into the first few weeks of spring. Technically though, were the spring equinox — which falls on Saturday 23 September this year — to be observed as the beginning of spring (as is the case in parts of the world), then it would still be winter in Australia. A heatwave in winter, fancy that.

Long range forecasts are not always accurate though, and conditions may change between now and the weekend. Still, such warm temperatures in the middle of September are alarming to say the least.

And for anyone wondering, each season in Australia commence on the first days of March, June, September, and December, because Australia adheres to the meteorological seasonal system. Many northern hemisphere nations however observe the astronomical season convention, meaning seasons change on about the beginning of the third week in March, June, September, and December.

Better building design will make air conditioning more environmentally friendly

5 September 2023

Ways are being sought to reduce the harmful environmental impact of air conditioning (AC) systems, which remain essential for health and well-being, starting with how buildings are designed and constructed in the first place:

“We need to design our buildings in a way that consumes less energy. We need to insulate them better. We need to ventilate them better,” explained Ankit Kalanki, a manager at Third Derivative, a climate tech accelerator co-founded by the sustainability research organization RMI. “These strategies are very important. We can reduce the air conditioning demand in the first place, but we cannot eliminate that.”

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climate change, environment, health

Rising humidity levels are making heatwaves unbearable

31 July 2023

Heatwaves, which have been experienced in a number of regions in the northern hemisphere in recent weeks, are being aggravated by increased levels of humidity, which is being precipitated by climate change. While it might be thought higher temperatures would cause moisture to evaporate, warmer air is capable of holding more water vapour than cooler air.

Sea surface temperatures have been steadily climbing globally, as the oceans absorb something like 90 percent of the excess heat that humans are adding to the atmosphere. But since March, global sea surface temperatures have been skyrocketing above the norm. The North Atlantic, in particular, remains super hot, loading Europe’s air with extra humidity.

Parts of the east coast of Australia saw higher levels of humidity last week, which had the effect of “taking the bite” out of otherwise relatively cooler temperatures. That’s about the only instance when high humidity has an upside. Those sorts of humidity levels will be far from welcome come summer.

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