Weekly Australian Climate, Water and Agricultural Update, 30 May 2024

For the week ending 29 May 2024, a high-pressure system brought dry conditions to much of Australia. In Western Australia, a cold front brought rainfall totals of up to 100 millimetres in isolated areas across the southwest coast. In the northeast Queensland, a low-pressure system brought rainfall totals of up to 100 millimetres in scattered areas. Tasmania recorded a maximum of 50 millimetres of rainfall.

Across cropping regions, isolated falls of between 10 and 50 millimetres were recorded in southern Western Australia. Little to no rainfall was recorded across the remainder of Australian cropping regions this week. Mostly dry conditions in New South Wales and Queensland would have allowed planting of winter crops and harvest of summer crops to continue without delay. Across Victoria and South Australia, the lack of rainfall would have continued to delay the germination of winter crops and resulted in a continual decline in soil moisture. Rainfall in southern Western Australia will likely support the germination and establishment of crops and pastures growth.

Rainfall for the week ending 29 May 2024

Over the 8 days to 6 June 2024, a northwest cloud band extending from northwest to southeast Australia is expected to bring severe weather and thunderstorms across its passage. This weather system is expected to result in rainfall totals of up to up 50 millimetres in northern areas of Western Australia, southern areas of Northern Territory and south-western Queensland, and up to 100 millimetres in New South Wales and Victoria. Cold fronts are expected to bring rainfall totals of up to 100 millimetres in south-western Western Australia and Tasmania and up to 25 millimetres in South Australia.

Across cropping regions, widespread falls are expected in most areas. The heaviest falls are expected across New South Wales, southern Queensland, Victoria and the western parts of Western Australia, with these areas likely to receiving between 10 and 50 millimetres. Parts of eastern Victoria can record up to 100 millimetres of rainfall. Up to 25 millimetres is expected across much of South Australia, while remaining areas in Western Australia and northern Queensland are expected to receive up to 10 millimetres. If realised, this rainfall will provide relief to cropping regions in Western Australia, South Australia and Victoria, allowing germination of dry sown crops. However, excessive rainfall across southern Queensland and northern New South Wales, is likely to interfere with the harvesting of summer crops and delay planting activities of winter crops.

Total forecast rainfall for the period 30 May to 6 June 2024

The most recent rainfall outlook for June 2024 provided by the Bureau of Meteorology indicates an increased likelihood of below median rainfall across large areas of eastern, southern and northern Australia. Above median rainfall is more likely across western parts of Western Australia and in isolated areas in the tropics and southern Tasmania. There is an equal chance of either above or below median rainfall likely elsewhere.

According to Bureau of Meteorology’s climate model, for June 2024 there is a 75% probability of rainfall totals between 25 to 50 millimetres across parts of New South Wales and coastal Queensland and much of Victoria, and southern South Australia. High elevation and coastal areas may receive up to 100 millimetres of rainfall in these states. The far southwest of Western Australia and western Tasmania are anticipated to receive up to 200 millimetres of rainfall. Northern Australia is expected to remain largely dry, typical of this time of the year.

Across cropping regions, there is a 75% chance of rainfall totals between 10 to 50 millimetres in New South Wales, Victoria, South Australia and up to 100 millimetres in Western Australia. In Queensland, a maximum of 10 millimetres is expected. If realised, these expected rainfall totals should be sufficient to allow for the germination and establishment of winter crops.

Rainfall totals that have a 75% chance of occurring in June 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 June through August indicates that above median rainfall is more likely across much of the southern half of Australia, with exceptions of Victoria and Tasmania, and southern parts of South Australia where below median to median rainfall is more likely. Remaining areas have an equal chance of having above or below median rainfall.

Across cropping regions, the probability of exceeding median rainfall is between 40% and 60% in Queensland and Victoria, while Western Australia and New South Wales cropping regions have a higher probability (between 50 and 70%) of receiving above median rainfall. Below median rainfall is likely in scattered areas of South Australia.

Chance of exceeding the median rainfall June to August 2024

Note: The world precipitation percentiles indicate a ranking of precipitation for March, with the driest (0th percentile) being 0 on the scale and the wettest (100th percentile) being 1 on the scale. Percentiles are based on precipitation estimates from the NOAA Climate Prediction Center’s Climate Anomaly Monitoring System Outgoing Precipitation Index dataset. Precipitation estimates for April 2024 are compared with rainfall recorded for that period during the 1981 to 2010 base period. Source: International Research Institute for Climate and Society

The outlook for June to August 2024 suggests there is at least a 75% chance of rainfall totals of up to 200 millimetres across much of southern Australia, with up to 400 millimetres likely in high elevations of New South Wales and Victoria. In western Tasmania, rainfall is expected to reach up to 800 millimetres over the period. The far southwest of Western Australia is likely to receive up to 600 millimetres of rainfall. In contrast, northern Australia is likely to remain largely dry, typical of this time of the year.

In cropping regions, there is at least a 75% chance of receiving between 100 and 200 millimetres across much of South Australia, Western Australia, Victoria and New South Wales. Geraldton area in Western Australia has a 75% chance of receiving up to 300 millimetres of rainfall. Up to 100 millimetres of rainfall is expected in Queensland.

If realised, these expected rainfall totals will likely be sufficient to support growth and establishment of winter crops, particularly in South Australia, Western Australia and western parts of Victoria where soil moisture levels are currently well below average. Expected rainfall across remaining cropping regions will further boost soil moisture profile and will assist in maintaining above average forecast winter crops yields.

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 June to August period.

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