Weekly Australian Climate, Water and Agricultural Update, 25 July 2024

For the week ending 24 July 2024, cold fronts and a series of troughs brought rainfall to southern Australia, while a high-pressure system kept the north and centre of the country largely dry. Up to 150 millimetres was recorded in isolated areas of Western Australia and Tasmania. In South Australia, Victoria, and southern New South Wales, up to 100 millimetres of rainfall was recorded in scattered areas.

Across cropping regions, rainfall totals of between 5 and 25 millimetres were recorded in South Australia, southern Victoria and the far southeast of New South Wales. In Western Australia, cropping regions received between 15 and 100 millimetres, with the highest falls recorded along the western coast. Little to no rainfall was recorded in remaining cropping regions. Recent rainfall continues to benefit the build-up of soil moisture across southern and western areas of the wheat/sheep zone. By contrast, lack of rainfall in Queensland is seeing a drawdown in stored soil moisture.

Rainfall for the week ending 24 July 2024

Over the 8 days to 1 August, a series of cold fronts in the southwest and southeast of the country are expected to bring rainfall totals of up to 100 millimetres in Western Australia and up to 50 millimetres in Tasmania and southern areas of Victoria and South Australia. A northwest cloud band is expected to bring rainfall of between 5 and 10 millimetres to northern and central regions.

Across cropping regions, rainfall totals of between 5 and 10 millimetres are forecast for parts of Queensland, Victoria, and South Australia. Much of New South Wales is forecast to receive between 5 and 25 millimetres of rainfall. Meanwhile, Western Australia is expected to receive widespread falls of up to 10 millimetres in the east increasing to 50 millimetres in western areas. If realised, these rainfall totals are expected to continue supporting winter cropping across much of southern Australia, but dry conditions in parts of Queensland may contribute to a decline in soil moisture levels.

Total forecast rainfall for the period 25 July to 1 August 2024

The most recent rainfall outlook for August 2024 provided by the Bureau of Meteorology indicates an increased likelihood of above median rainfall across central to southeast Australia, as well as in the southwest. There is an increased likelihood of below median rainfall across parts of northern Australia, central areas of Western Australia and southern parts of Tasmania.

According to Bureau of Meteorology’s climate model, for August 2024 there is a 75% probability of rainfall totals between 10 and 100 millimetres across New South Wales, Victoria, Tasmania, southern South Australia and Western Australia. Southern Queensland is expected to receive up to 25 millimetres of rainfall. Alpine areas in New South Wales, Victoria, and the far west of Western Australia will likely receive rainfall of up to 200 millimetres. Tasmania is expected to receive up to 300 millimetres of rainfall. The northern areas of the country are expected to remain largely dry, typical of this time of year, with exceptions in parts of the tropical northeast Queensland where up to 25 millimetres of rainfall are expected.

Across cropping regions, there is a 75% chance of receiving between 10 and 50 millimetres of rainfall in New South Wales, Victoria, South Australia and Western Australia. Isolated areas in these states can receive up to 100 millimetres of rainfall. In Queensland, rainfall totals of between 5 and 25 millimetres are expected across southern cropping regions, while little to no rainfall is expected for northern cropping regions. If realised, these rainfall totals are likely to be sufficient to support growth of crops through remaining of winter. In Queensland cropping regions, this expected lack of rainfall in the central to northern areas may have a negative effect on the winter crop development.

Rainfall totals that have a 75% chance of occurring in August 2024

The El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) climate drivers are currently neutral and having minimal influence on Australian rainfall.

The rainfall outlook for August through October 2024 indicates that above median rainfall is more likely across the interior, and eastern and south-western areas of the country. In contrast, much of Western Australia, and parts of the tropics and southern Tasmania are expected to receive below median rainfall, with the probability below 40% of average rain in these areas. Remaining areas have equal chance of receiving above or below median rainfall.

Across cropping regions, the probability of receiving median rainfall is between 45% and 70% in Queensland, New South Wales and Western Australia. There is an equal chance of either above or below median rainfall in South Australian and Victorian cropping regions. If realised, this rainfall would support ABARES forecasts of above average winter crop yields.

Chance of exceeding the median rainfall August to October 2024

The outlook for August through to October suggests a 75% chance of rainfall totals between 25 and 200 millimetres occurring in the southern part of the country, with heavier falls of up to 600 millimetres forecast for isolated areas of far southwest Western Australia, and alpine regions of Victoria and New South Wales. Western Tasmania is expected to receive falls in excess of 600 millimetres in isolated areas. In Queensland, falls of between 25 and 100 millimetres are expected in the southeast and parts of the northeast, with coastal areas likely to receive up to 200 millimetres of rainfall. Much of the remainder of the country is expected to receive little to no rainfall, typical of this time of the year.

In cropping regions, there is at least a 75% chance of receiving between 50 and 200 millimetres of rainfall across much of New South Wales, Victoria, South Australia and Western Australia. In Queensland, falls of between 25 and 100 millimetres are expected, with drier conditions forecast for far northern cropping regions.

These expected rainfall totals are likely to be sufficient to support growth of winter crops, boost soil moisture profile and assist in maintaining above average crops yields in most winter regions and provide a favourable start to the summer cropping season.

Livestock producers, especially those in the south, are expected to experience close to average pasture production on the back of the improving rainfall outlook over the August to October period.

Rainfall totals that have a 75% chance of occurring August to October 2024