Temperatures across southern Queensland and northern NSW have been up to 13 degrees Celsius above the August maximum on a number of days this week, and while climate change may the words on everyone’s lips, it is not the whole story.
Why so hot?
The consensus among climate scientists the ABC spoke to is that it is hot because of what has not been happening in the atmosphere.
The weather across the country has been very stable in the first half of winter.
With few cold air intrusions to mix things up, pressure and temperatures have been able to build.
El Nino Southern Oscillation (ENSO) and another ENSO-like driver called the Indian Ocean Dipole (IOD) have been neutral for a while, and that means they are not to blame for the hot weather.
This means other climatic systems that usually sit in the back seat are getting their chance at the wheel.
One of those other systems is the Southern Annular Mode (SAM).
In winter, SAM affects whether storms in the Southern Ocean impact Australia.
According to Melbourne University climatologist Andrew King, the kind of extreme warmth over central Australia could be partly due to storm tracks passing to the south of Australia.
“We know that the storm track is moving southwards, away from Australia, due to climate change,” Dr King said.
“This means the kind of weather we’ve seen this winter will likely be more common in future.”
SAM has been in a positive mode in late autumn and early winter, and the resulting unusually stable weather has caused all sorts of trouble.
Farmers right across the south of Australia have faced a frustrating lack of early winter rain, and wind energy providers have been plagued by a lack of wind.
Luckily, SAM now appears to have moved to a neutral mode, and there has finally been wind and rain across the south of the country.
Source: www.abc.net.au
