Weekly update - 24 September 2020

Weekly Australian Climate,
Water and Agricultural Update

Key issues

  • During the week ending 23 September 2020, frontal systems moved east over Australia and moist onshore flow developed along the east coast of Queensland, bringing rainfall and storms to parts of southern and eastern Australia. Moderate falls across parts of eastern Australia cropping regions are likely to support current yields and boost soil moisture during the final stages of winter crop development.
  • It is expected that cooling in the central Pacific Ocean will continue and a La Niña event is likely to eventuate in spring. Similarly, large parts of the Indian Ocean are warmer than average and the majority of models surveyed are expected to exceed negative IOD values in October. The development of these major climate drivers are potentially contributing to the above average spring and early summer rainfall outlook for parts of Australia.
  • There is a high chance that rainfall between October and December will be sufficient to sustain above average crop and pasture production through the remainder of spring in areas where soil moisture is close to average or above average. With the exception of parts of Western Australia, these highly probable rainfall totals – if realised - represent an excellent finish to the 2020 winter growing season across southern Australia and start to the 2020-21 summer cropping season and wet season across northern Australia. These rainfall totals are consistent with forecasts embodied in the ABARES September 2020 editions of the Australian crop report and Agricultural commodities.
  • Over the next eight days, a frontal system is expected to bring showers and storms to parts of south-eastern Australia. Across cropping regions, rainfall of between 10 and 25 millimetres is expected across much of southern New South Wales, Victoria and South Australia. These falls are likely to support favourable winter crop yields and boost soil moisture in south-eastern Australia during the final stages of winter crop development.
  • Water storage levels in the Murray-Darling Basin (MDB) increased between 16 September 2020 and 23 September 2020 by 51 gigalitres (GL). The current volume of water held in storage is 13,764 GL which represents 54 per cent of total capacity.
  • Allocation prices in the Victorian Murray below the Barmah Choke decreased from $300 per ML from 17 September 2020 to $290 per ML 24 September 2020. Prices are lower in the Goulburn-Broken, Murrumbidgee and regions above the Barmah Choke, due to binding of the Goulburn intervalley trade and Murrumbidgee export limits, and the Barmah Choke trade constraint.

Climate

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Rainfall this week

During the week ending 23 September 2020 frontal systems moved east over Australia and moist onshore flow developed along the east coast of Queensland, bringing rainfall and storms to parts of southern and eastern Australia. Rainfall totals of between 10 and 50 millimetres were recorded across much of New South Wales, south-western and central Queensland, southern South Australia and Tasmania and parts of north-eastern Queensland, Victoria, southern Western Australia and the north and east of the Northern Territory. Rainfall in excess of 50 millimetres was recorded across isolated parts of south-western Queensland, central South Australia and western Tasmania.

In Australia’s cropping regions, rainfall totals of between 10 and 50 millimetres were recorded across much of New South Wales and parts of western and central Queensland, eastern and southern Victoria, southern Western Australia and scattered parts of South Australia. Little to no rainfall was recorded across remaining cropping regions during the week ending 23 September 2020.

The significant falls in parts of eastern and southern cropping regions are likely to support current yields and boost soil moisture. In contrast, in regions that recorded below average rainfall during winter and have low soil moisture reserves, particularly Western Australia, these largely dry conditions are likely to be a concern for yield prospect and pasture production as temperatures increase.

Rainfall for the week ending 23 September 2020

Map showing weekly rainfall totals in Australia. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

©Commonwealth of Australia 2020, Australian Bureau of Meteorology - Issued: 23/09/2020

Note: The rainfall analyses and associated maps utilise data contained in the Bureau of Meteorology climate database, the Australian Data Archive for Meteorology (ADAM). The analyses are initially produced automatically from real-time data with limited quality control. They are intended to provide a general overview of rainfall across Australia as quickly as possible after the observations are received. For further information go to http://www.bom.gov.au/climate/rainfall/

Climate Drivers

Following a generally favourable winter cropping season-to-date in Australia, there is interest in how the remainder of the growing season may pan out. To gain some insight it is important to look at the major climate drivers—the Indian Ocean Dipole (IOD) and the El Nino Southern Oscillation (ENSO)—that influence spring rainfall across southern Australia. If La Niña and negative IOD conditions were to eventuate as forecast by a range of international models surveyed by the Bureau of Meteorology, these key climate drivers would become the major influencing factor for the spring and early summer rainfall outlook across eastern Australia.

If a La Niña and negative IOD were to eventuate during spring, they are likely to generate the favourable seasonal conditions that were central in developing ABARES winter and summer crop production forecasts embodied in the ABARES September 2020 editions of the Australian crop report and Agricultural commodities. The enhanced probabilities of a wetter than average spring rainfall would also benefit spring pasture growth across eastern and northern Australia, summer crop production and an early northern rainfall onset.

The Bureau of Meteorology’s ENSO Outlook remains at La Niña ALERT. This means that while the El Niño-Southern Oscillation is currently neutral, the chance of a La Niña forming during the southern hemisphere spring has increased to around 70% - roughly three times the normal likelihood.

A La Niña ALERT is not a guarantee that a La Niña will occur; it is an indication that some of the typical precursors of an event are in place. The potential impact of a La Niña event on agricultural production across southern Australia decreases if the event forms during spring or summer, as it has a shorter time to strengthen and will persist for a shorter time before it decays in late summer.

Cooling in the central and eastern Pacific Ocean has continued and has extended along the eastern tropics south of the equator. All of the eight surveyed climate models suggest the cooling will exceed La Niña thresholds in spring.

Difference from average sea surface temperature observations 7 September to 13 September 2020

Map showing the global sea surface temperature observations difference from average during the previous week. The climatology baseline used is 1961 to 1990. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

Atmospheric indicators are consistent with the early stages of La Niña development, with generally stronger than average trade winds, decreased cloudiness near the Date Line and the Southern Oscillation Index (SOI) has exceeded the threshold into La Niña values for most of the past three weeks. Sustained SOI values above 7 typically indicate La Niña and for the period ending 21 September the 30-day SOI value was 8.3 and for the period ending 13 September the 90-day value was still within the neutral ENSO range at 5.0.

30-day Southern Oscillation Index (SOI) values ending 21 September 2020

Graph showing the 30-day Southern Oscillation Index (SOI) values for the past two years. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

The El Niño–Southern Oscillation (ENSO) is currently neutral but very close to La Niña thresholds, with monthly sea surface temperature anomalies for NINO3.4 region likely to reach -0.8 by October. It is expected that further cooling in the central tropical Pacific Ocean will occur and a La Niña event is likely to eventuate, with all of the eight surveyed models exceeding La Niña thresholds in October and persisting above La Niña thresholds until the end of the year at least, potentially contributing to the above rainfall outlook for parts of Australia during the remainder of spring and early summer.

Monthly sea surface temperature anomalies for NINO3.4 region

Plume graph from ACCESS-S forecasts showing the recent monthly, month-to-date and forecast mean sea surface temperature anomalies for the NINO3.4 region. This graph uses a base period of 1990-2012. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

Large parts of the Indian Ocean are warmer than average, however the weak cooler than average anomalies in the western Indian Ocean have reduced during recent weeks. The Indian Ocean Dipole (IOD) index is currently neutral and is likely to reach negative IOD threshold values during October. IOD values at or below -0.4 must be sustained for eight weeks for this to be considered a negative IOD event. The majority of models surveyed are expected to exceed or have met IOD thresholds during October and three models are expected to maintain these values during November. A negative IOD typically brings above average rainfall to south-eastern Australia, and the Northern Territory and Queensland during spring and is associated with an early northern rainfall onset.

Monthly sea surface temperature anomalies for IOD region

Plume graph from ACCESS-S forecasts showing the recent monthly, month-to-date and forecast mean sea surface temperature anomalies for the IOD region. This graph uses a base period of 1990-2012. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

The Southern Annular Mode (SAM) is currently neutral and expected to become positive briefly, then weakly negative, followed by weak positive values during much of October. The SAM refers to the north-south shift of the band of rain-bearing westerly winds and weather systems in the Southern Ocean compared to the usual position. When SAM is positive during spring, this band of westerly winds is further south than normal. This allows for increased moist onshore flow from the Tasman and Coral seas and more rainfall across eastern Australia and a reduced chance of extreme heat.

Southern Annular Mode (SAM) daily index

Plume graph from ACCESS-S forecasts showing the daily Southern Annular Mode (SAM) index values for approximately the past 30-days and the forecast mean values for approximately the next 30-days. This graph uses a base period of 1990-2012. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

National Climate Outlook

These climate outlooks are generated by ACCESS–S (Australian Community Climate Earth-System Simulator–Seasonal). ACCESS–S is the Bureau of Meteorology's dynamical (physics-based) weather and climate model used for monthly, seasonal and longer-lead climate outlooks.

For further information, go to http://www.bom.gov.au/climate/ahead/about/

The latest rainfall outlook released by the Bureau of Meteorology suggests above average rainfall is more likely for the eastern two thirds of mainland Australia and northern and eastern Tasmania. There are roughly equal chances of a wetter or drier than average October across the remainder of the country.  

The rainfall outlook for October to December 2020 suggests that wetter than average conditions are likely for much of the eastern two thirds of mainland Australia and much of Tasmania. Drier than average rainfall is likely for parts of central-western mainland Australia and south-western Tasmania. There are roughly equal chances of a wetter or drier than average three months across the remainder of the country (Bureau of Meteorology ‘National Climate Outlook’, 17 September 2020). Bureau of Meteorology rainfall outlooks for October to December have greater than 65% past accuracy across much of eastern Australia, with higher accuracy, greater than 75%, in the north-east and parts of the south-east. There is lower accuracy, less than 65%, across much of the remainder of Australia, with less than 55% past accuracy across parts western and central Australia.

Chance of exceeding the median rainfall October to December 2020

Map showing the chance of exceeding median rainfall between October to December 2020 in Australia. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

©Commonwealth of Australia 2020, Australian Bureau of Meteorology - Issued: 17/09/2020

The outlook for October 2020 suggests that there is a 75% chance of rainfall totals between 10 and 50 millimetres across much of the eastern half of Australia and far south-western Australia. Rainfall totals in excess of 50 millimetres are likely across parts of south-eastern Australia, north-west of the Northern Territory and much of Tasmania.

There is a high chance of recording close to average October rainfall totals across most agricultural regions, with the exception of south-western Australia. These totals are likely to support above average winter crop yield potentials across New South Wales and Victoria, and parts of South Australia.

In cropping regions there is a 75% chance of rainfall totals between 25 and 100 millimetres across New South Wales and much of Queensland and Victoria. There is a 75% chance of rainfall totals between 10 and 50 millimetres in cropping regions across northern Queensland, South Australia and southern Western Australia, with rainfall totals between 1 and 5 millimetres across the remainder of the Western Australia wheat belt for October 2020.

Rainfall totals that have a 75% chance of occurring October 2020

Map showing the rainfall totals that have a 75% chance of occurring during October 2020 in Australia. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

©Commonwealth of Australia 2020, Australian Bureau of Meteorology - Issued: 17/09/2020

The outlook for October to December 2020 suggests that there is a 75% chance of rainfall totals between 50 and 200 millimetres across much of northern, eastern and central Australia and parts of far southern Australia. Lower rainfall totals between 25 and 50 millimetres are likely across the much of inland Western Australia and the remainder of central Australia. Rainfall totals in excess of 200 millimetres are likely across parts of eastern New South Wales, eastern and northern Queensland, eastern Victoria, north of Western Australia, north of the Northern Territory and western and northern Tasmania.

These totals indicate that the northern rainfall onset may occur across most of northern Australia during October to December. The onset occurs when the total rainfall after 1 September reaches 50 millimetres, this is considered approximately the amount of rainfall required to stimulate plant growth. 

In many areas where soil moisture is close to average to above average for this time of year, there is a high chance of recording October to December rainfall totals sufficient to sustain above average crop and pasture production through the remainder of spring.

In cropping regions, there is a 75% chance of receiving between 100 and 200 millimetres across most of New South Wales, Queensland and parts of southern Victoria and central South Australia. Rainfall totals greater than 200 millimetres are likely across cropping regions in parts of central and south-eastern Queensland and north-eastern New South Wales. Rainfall totals between 25 and 100 millimetres are likely across cropping regions in northern Victoria, much of South Australia and the central and southern Western Australian wheat belt between October and December 2020.

With the exception of parts of Western Australia these high chance expected rainfall totals are equivalent to the seasonal median between (1990 and 2012) and represent an excellent finish to the 2020 winter growing season across southern Australia and start to the 2020-21 summer cropping season and wet season across northern Australia. 

Rainfall totals that have a 75% chance of occurring October to December 2020

Map showing the rainfall totals that have a 75% chance of occurring during October 2020 in Australia. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

©Commonwealth of Australia 2020, Australian Bureau of Meteorology - Issued: 17/09/2020

The temperature outlook for October to December 2020 indicates that temperatures are likely to be between 1°C to 2°C above the 1990-2012 average across parts of northern Australia during the night-time. Average (- 1°C to 1°C) daytime and night-time temperatures are likely for the remainder of the country (Bureau of Meteorology ‘National Climate Outlook’, 17 September 2020).

Predicted maximum temperature anomaly for October to December 2020

Map showing the predicted maximum temperature anomaly for the next three months in Australia. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

Predicted minimum temperature anomaly for October to December 2020

Map showing the predicted minimum temperature anomaly for the next three months in Australia. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

Rainfall forecast for the next 8 days

A frontal system is expected to bring showers and storms to parts of south-eastern Australia and troughs are expected to bring rainfall to isolated parts of south-western and northern Australia during the week. Rainfall totals of between 10 and 50 millimetres are forecast for much of Victoria and Tasmania, and parts of southern New South Wales, south-eastern South Australia, south-western Western Australia and the north-west of the Northern Territory.

In cropping regions, rainfall of between 10 and 25 millimetres is expected across much of southern New South Wales, Victoria and South Australia. Rainfall totals of between 5 and 10 millimetres are expected across remaining cropping regions in parts of central and southern New South Wales, northern Victoria, central and northern South Australia and south-western Western Australia during the next eight days.

These falls are likely to support favourable winter crop yields and boost soil moisture in south-eastern Australia during the final stages of winter crop development.

Total forecast rainfall (mm) for the period 24 September 2020 to 1 October 2020

Map of the total forecast rainfall for the next 8 days. Image provided by the Bureau of Meteorology. Please refer to accompanying text for a more detailed description.

©Commonwealth of Australia 2020, Australian Bureau of Meteorology - Issued: 24/09/2020

Note: This rainfall forecast is produced from computer models. As the model outputs are not altered by weather forecasters, it is important to check local forecasts and warnings issued by the Bureau of Meteorology.

Commodities

Current indicators – 24 September 2020

Indicator Week ended Unit Latest price Price week prior Weekly change Price 12 months prior Year on year change Chart

Selected World Indicator Prices

AUD/USD Exchange rate 23-Sep US$/A$ 0.72 0.73 -1% 0.67 7% chart
Wheat – US no. 2 hard red winter wheat, fob Gulf 23-Sep US$/t 252 249 1% 207 21% chart
Coarse Grains – US no. 2 yellow corn, fob Gulf 19-Aug US$/t 150 145 3% 157 -4% chart
Canola – Rapeseed, Canada, fob Vancouver 23-Sep US$/t 386 411 -6% 366 5% chart
Cotton – Cotlook 'A' Index 23-Sep USc/lb 71 71 -1% 72 -1% chart
Sugar – Intercontinental Exchange, nearby futures, no.11 contract 23-Sep USc/lb 13 13 6% 11 16% chart
Wool – Eastern Market Indicator 23-Sep Ac/kg clean 1,036 937 11% 1,513 -32% chart
Wool – Western Market Indicator 23-Sep Ac/kg clean 1,085 984 10% 1,992 -46% chart

Selected Australian grain export prices

Milling Wheat – APW, Port Adelaide, SA 23-Sep A$/t 341 331 3% 363 -6% chart
Feed Wheat – ASW, Port Adelaide, SA 23-Sep A$/t 326 316 3% 354 -8% chart
Feed Barley – Port Adelaide, SA 23-Sep A$/t 277 271 2% 336 -18% chart
Canola – Kwinana, WA 23-Sep A$/t 667 651 3% 668 0% chart
Grain Sorghum – Brisbane, QLD 23-Sep A$/t 347 346 0% 435 -20% chart

Selected domestic livestock indicator prices

Beef – Eastern Young Cattle Indicator 23-Sep Ac/kg cwt 768 762 1% 489 57% chart
Mutton – Mutton indicator (18–24 kg fat score 2–3), Vic 16-Sep Ac/kg cwt 507 512 -1% 602 -16% chart
Lamb – Eastern States Trade Lamb Indicator 16-Sep Ac/kg cwt 713 680 5% 831 -14% chart
Pig – Eastern Seaboard (60.1–75 kg), average of buyers & sellers 09-Sep Ac/kg cwt 318 318 0% 360 -12% chart
Goat – Eastern States (12.1–16 kg) 16-Sep Ac/kg cwt 843 843 0% 902 -7% chart
Live cattle – Light steers ex Darwin to Indonesia 16-Sep Ac/kg lwt 355 355 0% 310 15% chart
Live sheep – Live wether (Muchea WA saleyard) to Middle East 11-Dec $/head 105 140 -25% N/A N/A chart

Global Dairy Trade (GDT) weighted average prices a

Dairy – Whole milk powder 16-Sep US$/t 2,985 2,884 4% 2,958 1% chart
Dairy – Skim milk powder 16-Sep US$/t 2,889 2,663 8% 1,972 47% chart
Dairy – Cheddar cheese 16-Sep US$/t 3,674 3,428 7% 3,663 0% chart
Dairy – Anhydrous milk fat 16-Sep US$/t 3,910 3,852 2% 5,709 -32% chart

a Global Dairy Trade prices are updated twice monthly on the first and third Tuesday of each month.

Selected world indicator prices
Selected domestic crop indicator prices
Selected domestic livestock indicator prices
Global dairy trade weighted average prices
Movements in selected fruit and vegetable prices
Data attribution

Water

Water storages, water markets and water allocations - current week

The Tableau dashboard may not meet accessibility requirements. For information about the contents of these dashboards contact ABARES.

 
Last reviewed: 24 September 2020
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