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La Niña likely to bring more rainfall and cyclones

The Bureau of Meteorology has released its Severe Weather Outlook for October to April, showing an increased risk of flooding for eastern Australia and tropical cyclones in the north, with roughly average potential for heatwaves and severe thunderstorms.

The current La Niña is likely to bring more rain to eastern and northern Australia, with some drought affected areas already seeing rainfall deficiencies ease and water storage levels increase.

La Niña also suggests an earlier than normal arrival for the first rains of this year’s northern wet season and an earlier monsoon onset for Darwin.

While recent decades have seen a decline in the number of tropical cyclones in our region, Bureau climatologist, Greg Browning, says this summer is likely to buck that trend.

“On average Australia sees 9 to 11 tropical cyclones each year, with 4 crossing the coast. With La Niña this year we are expecting to see slightly more tropical cyclones than average, and the first one may arrive earlier than normal,” Mr Browning said.

“Every northern wet season has had at least one tropical cyclone cross the Australian coast, so we can never be complacent. We know that cyclones can develop at any time throughout the tropical cyclone season, which runs from November to April,” he said.

“This means that communities right across northern Australia need to stay be prepared now, and stay informed from the very start of the tropical cyclone season in October, right though until April.”

After the catastrophic fires of last summer, it’s a very different bushfire outlook this season, with average fire potential for most parts.

“This fire season we’re expecting wetter than average conditions in eastern and northern Australia, so long running large bushfires are less likely, however a wetter spring can lead to abundant grass growth, which could increase fire danger as it naturally dries during summer.”

“Meanwhile, if dry conditions continue in southwest Western Australia as forecast, the potential for more fire weather days there could increase.”

The Bureau’s General Manager of Decision Support Services, Sandy Whight, said the lower fire risk across much of Australia is no reason for complacency.

“Southern Australia is one of the most bushfire prone places in the world in any summer and it’s important to remember that, right across Australia, even short periods of hot and windy weather will raise the fire risk, so communities need to have their bushfire plans ready.
 
“La Niña also brings more rain and increased humidity, which can mean fewer extreme heat days. But while heatwaves may not be as severe, the Bureau’s advice is that in southern areas they may last longer and be more humid – both of which can increase the risk to human health. Be sure to monitor the Bureau’s heatwave service, which provides information about the location and severity of heatwaves.”

The Bureau is committed to keeping Australians safe. We support emergency partners and the community to prepare for the impacts of severe weather through regular forecasts, warnings, monitoring and advice. 

Now, more than ever, it’s vital to heed the Bureau’s warning to Know your weather. Know your risk.

 

 
REGIONAL SNAPSHOTS

NEW SOUTH WALES

  • La Niña is likely to bring more rain than usual with an increased risk of widespread flooding
  • Heatwaves could be more humid and last for longer, especially in southern NSW
  • Normal bushfire potential, but more grass could provide more fuel in summer

QUEENSLAND

  • La Niña is likely to bring more rain than usual, with an increased risk of widespread flooding
  • Likely to see more tropical lows and cyclones than normal
  • Earlier start to the wet season across the north
  • Average numbers of severe thunderstorms

NORTHERN TERRITORY

  • La Niña is likely to bring more (and earlier) rain than usual
  • La Niña typically means earlier onset of the monsoon, higher likelihood for more tropical lows and cyclones than usual

WESTERN AUSTRALIA

  • La Niña’s impacts are not as marked in northern WA as they are in eastern Australia
  • Expect an earlier onset of the monsoon and increased risk of a pre-Christmas tropical cyclone off northwest WA 
  • Increased risk of widespread flooding in the north
  • A dry spring could increase fire potential in the south

SOUTH AUSTRALIA

  • More grass growth in spring could raise the risk of grass fires in summer
  • During La Niña, heatwaves may last longer and be more humid, though there may be fewer days of extreme heat compared an average season
  • La Niña is likely to bring more rain than usual through what is usually a very dry period in SA

TASMANIA

  • Normal bushfire potential, but more grass could provide more fuel in summer
  • Extreme heat days are more likely every season, due to the impacts of climate change
  • La Niña is likely to bring an increased risk of widespread flooding for eastern Tasmania 

VICTORIA

  • Increased risk of widespread flooding
  • Fewer extreme heat days but heatwaves may last longer and be more humid  
  • Long running bushfires are less likely, but more grass could provide more fuel in summer

AUSTRALIAN CAPITAL TERRITORY

  • La Niña is likely to bring more rain than usual with an increased risk of flooding
  • The ACT has normal bushfire potential, but people in rural areas and on the urban edge of Canberra are advised to plan for the potential of fast-moving grassfires

 

You can view the Bureau’s severe weather outlook page here: www.bom.gov.au/knowyourweather

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