Weekly Australian Climate, Water and Agricultural Update, 9 November 2023

For the week ending 8 November 2023, troughs brought widespread showers and storms to Queensland and New South Wales, and in country’s northwest. In contrast, little to no rainfall was recorded across the remainder of the country.

Across cropping regions, rainfall totals of up to 100 millimetres were recorded in Queensland and up to 50 millimetres in northern New South Wales. While welcomed, the rainfall recorded over the weekend is unlikely to spark widespread sorghum planting in northern New South Wales and Queensland but has brought some paddocks one fall closer to their next crop.

With the early sorghum-planting window now closing in southern Queensland and much of northern New South Wales, these falls are unlikely to spark any widespread sowing. In Central Queensland, where sorghum is not planted until January, falls were patchy, and has provided a boost to soil moisture levels.

In northern New South Wales some regions such as the Liverpool Plains can plant sorghum up to Christmas, some producers who recorded 40 millimetres or more may advance put in a dryland paddock to add to what has already gone in under irrigation. However, planting activity is unlikely to widespread planting activity because there’s just not enough soil moisture to plant with confidence.

Little to no rainfall recorded across remaining cropping areas. The dry conditions across remaining cropping regions would have allowed for the uninterrupted harvest of winter crops.

Rainfall for the week ending 8 November 2023

Pasture growth during the August to October period is typically low across large areas of central and northern Australia as it is firmly in the dry season. Across southern Australia, August to October pasture growth provides the spring flush which typically allows producers to cease winter supplementary feeding with grain and hay. It also influences the growth, branding and marking rates of lambs and calves, and the production of meat, milk, and wool over this peak production period.

For the 3 months to October 2023 below average rainfall totals and high temperatures resulted in well below average pasture production for this time of year across many grazing regions in eastern and southern Australia.

Modelled pasture growth was average to above average in Tasmania and parts of southern Victoria, southern and western New South Wales, and eastern South Australia. This growth will likely enable farmers to maintain current stock numbers and provide opportunities to replenish fodder supplies during late spring, if suitable fodder conservation conditions arise.

In contrast, modelled pasture growth was extremely low to below average across much of eastern and northern New South Wales, southern Queensland, South Australia, and southern parts of Western Australian grazing areas. This has led to a decline in pasture availability and precipitated a rapid increase in saleyard activity.

Relative pasture growth for 3-months ending October 2023 (1 August 2023 to 31 October 2023)

The timing of Northern Australia rainfall onset is important indicator for seasonal pasture growth and potential livestock production. The rainfall onset gives an indication of the accumulation of at least 50 millimetres of rainfall after 1 September to stimulate plant growth after the northern dry season. Between 1 September and 7 November 2023, much of northern Australia is yet to receive at least 50 millimetres of rainfall. The only regions that have recorded an early onset with at least 50 millimetres of rain is the coastal northeast and parts of interior southeast Queensland, part of northern Western Australia and Northern Territory.

Northern rainfall totals: 1 September to 7 November 2023

Number of days earlier or later than the long-term average onset date

The climate drivers with the largest potential impact on Australia’s climate patterns are the El Niño–Southern Oscillation (ENSO), Madden-Julian Oscillation (MJO), Indian Ocean Dipole (IOD) and Southern Annular Mode (SAM). These climate drivers are likely to influence pasture growth across southern Australia and the growth and yield prospects for winter crops.

The SAM is currently in positive stage and is expected to return to neutral stage in the coming weeks. During Spring, neutral SAM is associated with average climate conditions in southern Australia.

The MJO is currently weak but will strengthen and move eastwards into western Pacific later this week and lead to increased chance of showers and rain over northern Australia.

An El Niño and a positive IOD event are currently underway. When a positive IOD and El Niño occur together, their drying effect is typically stronger and more widespread across Australia. Their effect on spring rainfall is currently being observed. The El Niño is expected to persist till at least March 2024, while positive IOD is expected to remain active till January 2024.

ENSO and IOD forecast

The Bureau of Meteorology’s latest rainfall outlook for December 2023 indicates drier than average conditions are expected across large areas of northern, western and southern Australia.

The Bureau of Meteorology’s climate model suggests that for December 2023, there is a 75% chance of rainfall totals between 10 and 100 millimetres across eastern New South Wales, south-eastern Queensland, and southern Victoria. Rainfall totals in excess of 100 millimetres are expected across western Tasmania, northern Western Australia and Northern Territory.

Across cropping regions, there is a 75% chance of rainfall totals of between 10 and 100 millimetres in New South Wales and Queensland. December rainfall totals are expected to be below 25 millimetres for the remaining cropping regions.

These relatively low expected rainfall totals continue to represent a significant downside production risk for dry land summer crop production as well as pasture growth, particularly given the lack of rainfall in recent weeks and declining soil moisture levels across large areas of the cropping regions.

Rainfall totals that have a 75% chance of occurring in December 2023

The rainfall outlook for December 2023 to February 2024 suggests that there is close to equal chances of above or below median rainfall for central and south-eastern Australia, while below median rainfall is more likely for the remainder of the country.

Across cropping regions, close to equal chances of above or below median rainfall is likely across most cropping regions in south-eastern Australia and below median rainfall is likely in the western cropping areas.

Chance of exceeding the median rainfall December 2023 to February 2024

The outlook for December 2023 to February 2024 suggests there is a 75% chance of rainfall totals between 25 and 200 millimetres across much of Australia. The main exceptions are in large areas of South Australia and western and central parts of Western Australia where below 25 millimetres of rainfall are expected, and in areas of across tropical northern Australia, coastal New South Wales and western Tasmania, where rainfall totals in excess of 200 millimetres are expected.

In cropping regions, there is a 75% chance of receiving between 50 and 200 millimetres across New South Wales, Queensland and eastern Victoria while less than 50 millimetres of rainfall are likely across remaining cropping regions.

If these falls are realised, it is likely to be sufficient to support late spring and summer pasture growth across eastern and northern Australia. Additional while the dry start to spring has limited early planting of summer crops these falls may be sufficient to allow for later summer crop planting.

Rainfall totals that have a 75% chance of occurring December 2023 to February 2024

Over the 8 days to 16 November 2023, troughs and lows will generate showers and thunderstorms over eastern New South Wales and Victoria, northern Western Australia and Queensland, the north and east of the Northern Territory, and in central parts of Australia.

Across cropping regions, rainfall totals up to 50 millimetres are forecast for eastern New South Wales and the far southeast of Queensland, while little to no rainfall is expected elsewhere. The dry expected condition across most cropping regions will allow for the uninterrupted harvest of early planted winter crops. However, these dry conditions are expected to result in further delays to the timely planting of dryland summer crops.

Total forecast rainfall for the period 9 November 2023 to 16 November 2023