Australia is likely to be hit with increased severe weather over the next six months with more cyclones and flooding forecast.
The current La Nina may also bring drought-easing rain to some areas, with this year's northern wet season expected to arrive early, the Bureau of Meteorology said on Monday.
Climatologist Greg Browning said the La Nina was also likely to result in a rise in the number of cyclones forming between October and April.
"On average Australia sees nine to 11 tropical cyclones each year, with four crossing the coast," he said.
"With La Nina this year we are expecting to see slightly more tropical cyclones than average."
Bureau modelling suggests there's an increased risk of widespread flooding in Queensland, NSW, Victoria, Tasmania and northern Western Australia.
Higher-than-average rainfall is also predicted across much of the country, which is likely to increase humidity levels.
This could result in fewer severe heatwaves and extreme heat days in southern areas but they may last longer and be more sticky.
More rain also means there's also likely to be fewer catastrophic blazes this bushfire season.
"Long-running large fires are less likely, however, a wetter spring can lead to abundant grass growth, which could increase fire danger as it naturally dries during summer," Mr Browning said.
La Nina happens when equatorial trade winds become stronger, changing the ocean's surface currents and drawing cooler water up from the depths.
The enhanced trade winds also cause warmer surface waters to the north of Australia, potentially leading to heavier rainfall and more tropical cyclones than average.
Australia has been slammed with an extended period of below-average rainfall in many areas since early 2017, with numerous parts of the country enduring years of prolonged drought.
Southern Queensland and inland NSW are among the most severely affected regions, although recent heavy rainfall has brought relief to some areas.
There has also been a substantial lack of rain in the northwest of the country, with the past two wet seasons bringing below-average rainfall to much of the Northern Territory and WA's Kimberley region.
Southwest WA has also experienced two consecutive years with generally below-average rainfall.
The Bureau of Meteorology has urged communities across northern Australia to prepare for the tropical cyclone season and stay informed until April.
Australian Associated Press
