All hopes turn to La Nina delivering a wet summer

All hopes turn to La Nina delivering a wet summer

Weather
Where the rain fell between December 1, 2019 and November 30, 2020.

Where the rain fell between December 1, 2019 and November 30, 2020.

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Landholders are hoping that severe rainfall deficiencies can be turned around by the La Nina weather event.

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SEVERE rainfall deficiencies continue to plague big parts of Queensland and NSW, with large areas of showing big deficits during the past four years.

As the map shows, the area recording of rainfall deficiencies impacts on much of southern and central Queensland and particularly in northern NSW.

While there was some good rain in big areas of Queensland, resulting some high yielding winter crops on the Downs and excellent seasonal conditions in parts of western Queensland, big areas have continued to experience extreme drought.

The Queensland Government's 'Long Paddock' drought map paints a grim picture.

Rainfall deficiencies from December 1, 2016 to November 30, 2020.

Rainfall deficiencies from December 1, 2016 to November 30, 2020.

More than a third - or 67.4 per cent of the Queensland - is officially drought declared. That's made up of 41 local government areas and four part local government areas as well as 31 individual droughted properties in a further 12 local government areas.

Hopes are no well and truly pinned on the La Nina conditions, which promises to deliver a wetter than average summer.

BOM head of operational climate services, Dr Andrew Watkins, said there was increased risk of flooding in large parts of eastern Australia.

Dr Andrew Watkins said the climate outlook Queensland, NSW and Victoria this summer was average rainfall, with an increased risk of widespread floods.

Dr Watkins said that while the risk of bushfires isn't as high as last summer, fires will occur.

Drought continues to impact on 67.4 per cent of Queensland. Source - Queensland Government

Drought continues to impact on 67.4 per cent of Queensland. Source - Queensland Government

"There's a great chance of grass fires in some areas as recent rain and warm weather have led to vigorous vegetation growth. South eastern Australia is one of the most fire-prone regions in the world. Even short periods of hot and dry weather increase the risk of fire in summer."

Dr Watkins said northern Australia remained on track for an average to slightly above average cyclone season.

"On average, Australia sees nine to 11 tropical cyclones each year, with four crossing the coast," he said. "The first cyclone to develop in the Australian region occurs earlier during La Nina years."

Changing climate

According to BOM, Australia's climate has warmed on average by 1.44 deg C (plus or minus 0.24 deg C) since national records began in 1910.

This has resulted in an increase in the frequency of extreme heat events and seen a decline of about 16 per cent in April to October rainfall in the south west of Australia since 1970. Across the same region May-July rainfall has seen the largest decrease, by around 20 per cent since 1970.

However, rainfall and streamflow have increased across parts of northern Australia since the 1970s. Despite this, there has also been a decrease in the number of tropical cyclones observed since 1982.

BOM says the result has been an increase in extreme fire weather, and in the length of the fire season, across large parts of the country since the 1950s, especially in southern Australia.

BOM's forecast map showing the 75 per cent chance of rain across Australia from January 1 to March 31.

BOM's forecast map showing the 75 per cent chance of rain across Australia from January 1 to March 31.

At the global level, BOM says concentrations of all the major long-lived greenhouse gases in the atmosphere continue to increase, with global annual mean carbon dioxide concentrations reaching 410 parts per mmillion in 2019 and the CO2 equivalent of all greenhouse gases reaching 508ppm.

"These are the highest levels seen on Earth in at least two million years," Bom says.

"Despite a decline in global fossil fuel emissions of CO2 in 2020 associated with the COVID-19 pandemic, this will have negligible impact in terms of climate change.

"Atmospheric CO2 continues to rise, and fossil fuel emissions will remain the principal driver of this growth.

"Globally averaged air temperature at the Earth's surface has warmed by over 1 deg C since reliable records began in 1850. Each decade since 1980 has been warmer than the last, with 2010-19 being around 0.2 deg C warmer than 2000-09."

BOM says the world's oceans, especially in the southern hemisphere, are taking up around 90 per cent of the extra energy resulting from enhanced greenhouse gas concentrations.

Record weather

The long standing record for the most rain in a 24 hour period is 907mm, recorded at Crohamhurst in the Sunshine Coast hinterland on February 3, 1893. The other two in the top three are far north Queensland locales: Finch Hatton with 878.3mm on February 18, 1958, and 819.2mm on January 19, 1970 at Hecate near Cardell.

Queensland holds the record for the most amount of received in a year. In 2000 the Bellenden Ker near Babinda officially recorded an unbelievable 12.461 metres of rain - that's more than 490 inches.

Bellendan Ker also has the recorded for the highest monthly registration: 5.387m (212 inches) fell in the gauge during January 1979.

Queensland highest temperature to date for 2020 was a thermometer bursting 48.7 degrees Celcius at Birdsville Airport on December 5. That's still below the record 49.5 deg C record also set at Birdsville on Christmas Eve 1972.

However, Penrith Lakes, west of Sydney, holds the 2020 temperature record to date - a blistering 48.9 deg C recorded on January 4.

Oodnadatta Airport in far northern South Australia holds the record for Australia's highest officially recorded temperature - 50.7 deg C in January 1960 - four places above Queensland's best.

Queensland also holds the record - twice - for the fourth lowest temperatures officially measured in Australia. A very chilly -10.6 deg C was recorded at June 23, 1961, at Stanthorpe, and at Warwick on July 12, 1965.

Mitchell also copped -9.4 deg C at the post office on August 15, 1979. That same low was also measured at Stanthorpe on July 17, 1970.

The coldest place in Australian is Charlotte's Pass, which is located at an elevation of 1837m in the Snowy Mountains, close to Mount Kosciuszko. A particularly frosty -23 deg C was recorded there on June 29, 1994.

MORE READING: 'Australian ag shines in tough year'.

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