Australia's summer forecast – intense heatwaves and more cyclones

NSW and Victorian residents are going to have to brace for sweltering summer weather with more intense heat waves forecast.

The Bureau of Meteorology released its severe weather outlook for the rest of October until April on Monday.

The bureau last month said Australia will experience La Niña in the coming months. BOM manager of Climate Operations Dr Andrew Watkins said it means we’ve got warmer ocean water near Australia with cooler water off the south.

Melbourne residents seen in the heat.
Victoria could see longer heatwaves over the next few months. Source: BOM

It tends to favour rainfall and cloudiness, he said. And while there will be fewer days of extreme heat in southern states, they will be more intense this summer.

The severe weather outlook forecasts longer heat waves for South Australia, Victoria and NSW.

Meteorologist Diana Eadie said Australia “is warming”.

“Extreme heat days are more likely than compared to the past due to the impacts of climate change,” she said.

“This summer, rain and increased humidity, thanks to La Niña, means we face a reduced number of extreme heat days compared to recent years.

“But while heatwaves may not be as severe in southern areas, they may last longer and be more humid both of which can increase the risk to human health.”

A map produced by the Bureau of Meteorology showing Australia's chance of above median minimum temperature for December.
Much of Australia is in with a good chance of exceeding the median minimum temperature in December. Source: BOM

Hot temperatures for late October

By BoM’s definition, a heatwave occurs when maximum and or minimum temperatures “are unusually hot over a three-day period” in a specific location.

According to BoM’s climate outlook maps, most of Australia, if temperatures do exceed the average, most of the searing heat will occur between December and February.

However, the two weeks from October 19 through to November 1 promise to be hot too with southern NSW, South East Queensland, Darwin, Canberra, Melbourne and Perth all a 60-80 per cent chance of exceeding the median minimum temperature.

For Darwin and Hobart, it’s at 70-80 per cent.

A man on a paddle board in Blackwattle Bay as smoke haze from bushfires hangs over the CBD during hot weather in Sydney.
A man paddle-boards at Glebe's Blackwattle Bay in Sydney last summer as smoke haze fills the air. Source: AAP

Cyclones and flooding await

The La Niña event also brings more cyclones. In fact, in 2011 when Australia experienced La Niña South East Queensland was pummelled by flooding.

BoM believes eastern Australia and parts of the north will experience more rain over the coming months. It could lead to more mosquitoes too.

Climatologist Greg Browning said past years have seen less cyclones but the upcoming weeks and months will buck that trend.

"On average Australia sees nine to 11 tropical cyclones each year, with four 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.

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

Local watch as the swollen Balonne river floods the Andrew Nixon bridge in St George, south-western Queensland.
Residents look on after the Balonne river floods in St George in Queensland's southwest in February. Source: AAP

The Northern Territory could be hit with an earlier onset of monsoons while Queensland could see more cyclones bringing widespread flooding.

While spring through to summer is normally a dry period for South Australia it’s also likely to see more rain than usual while Tasmania, NSW, northern WA and the ACT could also see widespread flooding.

North Queensland might see an earlier start to the wet season too.

November through to January looks to be the wettest period though with parts of NSW’s north across the Queensland border to the Sunshine Coast, according to BOM’s climate outlook.

Beachgoers enjoy the hot weather at Coogee Beach.
A man soaks up the heat at Sydney's Coogee Beach. Source: Getty Images

October 19 through to November 1 has parts of northern NSW, South East Queensland and Darwin at about 65-70 per cent chance of surpassing median rainfall.

November could be a wet month for Sydney, Melbourne, Canberra and Adelaide too with a 65-75 per cent chance of exceeding median rainfall.

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