Strong La Nina leads to 25pc above average rainfall across nation

The Bureau of Meteorology annual data has confirmed that 2022 was markedly wetter than average for much of Australia.

Less obviously, it also found the year was warmer than average, although cooler than recent years.

National mean temperature was 0.50 degrees warmer than the 1961-1990 average, making 2022 the equal 22nd warmest year on record since national temperature records began in 1910.

On the rainfall front, the Bureau found that national rainfall was 25 per cent above the 1961-1990 annual average making 2022 the ninth-wettest year on record, with the impact of powerful La Nina and Indian Ocean Dipole events having strong influences on weather, particularly in eastern and southern Australia.

The Bureau confirmed this, saying rainfall was very much above average for the south-eastern quarter of the mainland, where persistent rain saw significant flooding affecting large areas, multiple times during the year.

Along with the two well publicised climate drivers in La Nina and the IOD negative, the BOM also said the Southern Annular Mode contributed to the wet conditions many experienced.

However, not everywhere was wet in 2022.

Rainfall was below average for western Tasmania, much of the north of the Northern Territory, and the far south-west of Western Australia, although the below average rain in parts of the WA cropping belt was not enough to stop farmers there ripping off a record crop.

The rain has put welcome reserves in key water storage in most areas, although there are still areas that have missed out.

The Bureau said key storages in central coast Queensland, western Tasmania, south-east New South Wales and western Victoria still had room to fill further.

The warm temperatures in northern Australia, Tasmania and parts of WA were enough to push the year overall into above average territory in spite of cooler weather in New South Wales, southern Queensland and parts of South Australia.

In terms of the climate drivers, the Bureau said the triple-dip La Nina, the third consecutive La Nina, was only the fourth time three successive La Nia events in a row have been observed in the Bureau record since 1900, the others being 1954-57, 1973-76, and 1998-2001.

NSW experienced the wettest conditions compared to average.

NSW overall had 860.24 mm rainfall in 2022, as an area average across the state, 54.7pc above average.

It was the second-wettest year on record for NSW, after 1950 where there was 915.61 mm rainfall.

In Victoria the state overall had 872.70 mm rainfall in 2022, as an area average across the state, 31.6pc above average.

It was the fifth-wettest year on record and the state's highest rainfall since 1974.

Queensland was 24.4pc above average for rainfall, averaging 74.27 mm rainfall in 2022, the state's highest rainfall since 2011.

South Australia overall had 310.45 mm rainfall in 2022, as an area average across the state, 38.7pc above average and the state's highest rainfall since 2016.

Tasmania overall had 1,318.75 mm rainfall in 2022, as an area average across the state, which is 2.9pc below average, reflecting the drier conditions in the state's west in particular.

Western Australia overall had 413.52 mm of rainfall in 2022, as an area average across the state, which was 21pc above average and the state's highest rainfall since 2017, in spite of the dry conditions in the south-west.

Original article written by Gregor Heard & published in FarmOnline on 13 January 2023.