Rain should ease across parts of eastern Australia in the coming weeks, with the weather bureau predicting La Niña is showing signs of “declining in strength”.
University of Melbourne senior lecturer in climate science Dr Andrew King said this weakening La Niña influence meant the weather would be warmer.
Much of the country will experience a warmer-than-average summer, which is to be expected given climate change is causing the planet to warm, Dr King said.
“We usually have warmer-than-average summers now because our average was from the past,” he said.
“Australia has warmed by approximately 1.5 degrees Celsius since pre-industrial times, so we do have hotter summers than we’re used to.”
According to forecasters Weatherzone, we have already seen signs of La Niña’s weakening influence over the past week, with a period of dry weather in most parts of the country south of the tropics.
“As La Niña continues to weaken, the rain taps will of course not totally turn off. The weather will still deliver its daily and weekly mix of conditions irrespective of underlying climate drivers which point towards broader wet or dry trends,” Weatherzone noted on its website.
“But overall, a drying trend relative to average is now looking likely across much of the country.
“Whether we see the opposite of La Niña – El Niño – with its signature hot, dry summers in the near future is not yet clear.”
Meanwhile, the Bureau of Meteorology said on Tuesday: “La Niña continues in the tropical Pacific, but some indicators show signs of declining strength.”
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End to La Nina in sight
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Floods still possible
Given the amount of rain Australia has had, even average summer rainfall could lead to flooding.
“We don’t anticipate the next few months being really wet. But even average rainfall, with a few very wet events embedded, could mean some flooding in eastern Australia, given that the ground is already primed for more flooding,” Dr King said.
“It’s unlikely we’ll get the really big floods, as we’ve seen. But we certainly couldn’t rule out major flooding, just from the fact that doesn’t require too much rain to get some flooding.”
The bureau said there has been a trend towards more rainfall from high-intensity, short-duration rainfall events, especially across northern Australia.
An increased westerly flow and rainfall across parts of northern Australia may “lead to the onset of the Australian monsoon during this time, while also increasing the risk of tropical low and cyclone formation across the region”, it stated.
“[Monsoons] can affect the tropics, anywhere in the Northern Territory or in the far north of WA, around Broome. That’s where you typically see afternoon and evening thunderstorms,” meteorologist Dr Milton Speer said.
“The east coast in Queensland is slightly different because it gets moisture fed on through onshore winds. That causes thunderstorms in parts of the state.”
The longest day of the year
The summer solstice will occur later this week, marking the longest day of the year in the southern hemisphere.
Tweet from @weatherzone
This year’s summer solstice occurs at 8.48am AEDT on Thursday, when the Earth’s south pole reaches its furthest tilt away from the Sun.
“Earth’s tilt relative to the Sun changes constantly throughout the year. This changing angle of solar exposure causes our planet’s seasons and affects the length of day and night everywhere on Earth,” Weatherzone stated.
“Towards the end of December and June, the poles reach their maximum tilts towards and away from the Sun. This causes the year’s longest days and shortest nights on Earth.”
