The chances of Australia soon being affected by the rain-bearing La Niña weather system is climbing.
The Bureau of Meteorology (BOM) says there is now a 50% chance, double the normal likelihood. Coming just a week after news that the Bureau was already predicting a soggy season in eastern Australia, grey nomads would probably be wise to double check they’ve packed their umbrellas.
The ABC reports that the eastern Pacific Ocean has been slowly cooling in the past few months, and five of the seven climate models the bureau monitors are now indicating La Niña thresholds will be met in November and December.
La Niña is the phase of the El Niño Southern Oscillation (ENSO) over the Pacific Ocean that often leads to wetter-than-average conditions for eastern Australia.
The ABC reports that the last big La Niña event in 2011 brought devastating floods on the east coast, notably in Brisbane, Toowoomba, and the Lockyer Valley.
But not all La Niña events are as extreme.
Andrew Watkins, head of BOM’s operational climate services, told the ABC that, if La Niña did emerge this year it would be moderate … but that didn’t mean it wouldn’t pose a flood risk.
“Unfortunately, if we get rain in the coming months on top of that already sodden landscape then it increases the risk of flood because the soils and the rivers and the dams can’t absorb as much water,” Dr Watkins said. “Our outlook is looking fairly wet at the moment.”
However, the outlook is different on the south-west.
Recently, warm waters in the Indian Ocean had been feeding moisture into cloud bands reaching the south west and beyond, Dr Watkins told the ABC. But the south west’s rainfall is largely dependent upon rain-bearing fronts in the westerly wind band that circle the Southern Ocean. He says the positive Southern Annular Mode (SAM) will draw those winds south, meaning many will likely fail to reach the continent.
Wait and see what happens, might flush out covid
Nah, it’ll never happen, tell ’em Tim Flannery said that they’re dreaming!