NSW State Seasonal Update - November 2021

Prepared by NSW DPI

NSW overview

November 2021 was wet across most of New South Wales, with average to above average rainfall recorded across the state. This continues the strong production outlook, but the persistent wet conditions are now negatively impacting the winter grain crop. There is little sign of drought in the state and the NSW DPI Combined Drought Indicator (CDI) shows 95% of NSW in the Recovery or Non-Drought categories at the end of November. There is also a wet seasonal forecast for the next three months, with the official rainfall outlook indicating that there is a 65% or greater chance of rainfall being above the median values for the 2021/22 summer.

Moderate to major flooding has occurred across some catchments during November damaging winter cereal crops that were close or ready to harvest. The persistent wet conditions impact winter cereal crop yield through quality reductions or delayed harvests. Recent heavy rainfall will impact crop quality in some horticultural areas.

The irrigated crop forecast for the 2021-22 season remains high due to high soil moisture levels and water availability in the state’s reservoir and irrigation scheme. Water availability is expected to support a strong irrigated crop forecast for the 2021-22 season.

Pasture growth potential and livestock productivity remain high across most of NSW due to recent rainfall and high soil moisture levels. There are opportunities in many parts of the state to conserve fodder for future droughts. In many districts the nutritional value of pasture for livestock has started to plateau or decline with warmer temperatures. These seasonal conditions also create challenges for livestock producers, such as weed management.

Despite the strong overall outlook, parts of Western NSW and western areas of the Riverina and Murray regions continue to experience a slow, variable or delayed drought recovery. Rain fell in these regions during November however it will take more time to assess if this fully alleviates these conditions. The agronomic indictors of the CDI remain at low levels across parts of these regions and consistent follow-up rain is needed.

The latest Bureau of Meteorology (BoM) Seasonal Outlook indicates moderate to high chances of above median rainfall across NSW for the three months between December and February. The ENSO Outlook status is currently at La Niña. The Indian Ocean Dipole (IOD) is neutral and models indicate that the IOD will remain neutral in the coming months. Sea surface temperatures in the central-to-eastern tropical Pacific Ocean have cooled over the past three months and cool anomalies have strengthened in the eastern equatorial Pacific.

The CDI and its individual rainfall, soil moisture and crop/pasture growth metrics are leading biophysical indices of drought. Factors affecting production and economic responses usually lag the CDI. Further information about the correct interpretation of the CDI at a region and industry level is provided in the regional breakdown section of this report.

It is important to recognise the CDI provides an aggregated view of the State, and that on-ground conditions can be different to those displayed in the maps. They provide an ‘on average’ view of a particular region only. To report local conditions, use DPI Farm Tracker.

Rainfall

The rainfall anomaly data shows the difference between total monthly rainfall and the long-term average (1961-1990; Figure 2a). Most of NSW has received near average to above average rainfall in November. The highest rainfall totals have been across eastern NSW where falls above 100mm have been recorded (Figure 2b). Some regions have received rainfall totals above 300mm. The far north-west of NSW generally has received falls of below 50mm of rain.

Rainfall accumulation during the 2021 calendar year has been near or above average across NSW. Most of coastal NSW has received more than 1000mm in the year (Figure 2c). Eastern NSW has generally received above 600mm of the year. Western NSW has received below 300mm since the start of the year.

Temperature

Most of NSW experienced near average to below average maximum temperatures during November (Figure 3a). The average November maximum temperatures were generally above 18°C across eastern NSW, and above 24°C across central and western NSW.

Minimum temperatures were near average to slightly above average across most of NSW in November (Figure 3c). Mean minimum temperatures were above 9°C across most of the state (Figure 3d). Tablelands and Alpine regions at higher altitudes experienced cooler temperatures between 3 to 9°C.

Normalised Difference Vegetation Index (NDVI) Anomaly

The seasonal Normalised Difference Vegetation Index (NDVI, Figure 4) indicates that plant greenness levels are close to, or above normal across most of NSW for the September to November period. Lower than normal plant greenness remains evident across parts of the Western LLS region. Some areas affected by the 2019/20 bushfires also remain evident in the Central Tablelands and South East.

NSW Farm Dam Survey

The NSW Farm Dam Survey indicates large areas of western NSW have farm dam levels less than 20% of capacity (Figure 5). Dam levels are generally greater than 40% of capacity across eastern areas of NSW and above 80% capacity in regions that have received higher rainfall totals. This assessment does not include the addition to farm water storage from rainfall that was received in late November.

Soil Water Index

The Soil Water Index (SWI, Figure 6) indicates the majority of NSW is currently in the average to extremely high categories. This is a result of the rainfall that has been received over the last few months. Parts of western and south-western NSW are in the below average category.

Plant Growth Index

The Plant Growth Index (PGI, Figure 7) indicates that the majority of NSW is in the average to extremely high categories at the end of November. Parts of south-western and western NSW are in the below average category.

Rainfall Index

The Rainfall Index (RI, Figure 8) indicates that the majority of NSW is currently in the average to extremely high category. This reflects the distribution of average or above rainfall accumulated over the last 12 months. Smaller areas in the far west of the Western LLS region are in the below average RI category.

Drought Direction Index

The Drought Direction Index (DDI, Figure 9) tracks the 150-day trend of daily rainfall totals. The DDI indicates most of NSW is in a weak to strong wetting trend. This reflects the rainfall that has been received in the past few months.

Changes in the individual drought indicators may have occurred since this update was released. For the most current information, please visit DroughtHub.

CDI status for the regions

Figure 10 displays the CDI status for each individual Local Land Services (LLS) region to 30 November 2021. The following regional descriptions are based on data available until the end of November 2021.

Murray and Riverina regions

The Combined Drought Indicator (CDI, Figure 11) shows that conditions in the Riverina and Murray Local Land Services (LLS) regions have improved since the October Update. Most of both regions are in the Recovery or Non-Drought categories. Western areas of the Riverina and Murray LLS regions have remained in the Drought Affected category. Further rain is needed to support drought recovery.

Recent heavy rainfall will likely impact crop quality in some horticultural areas.

The seasonal NDVI anomaly data (Figure 12) shows that most of the Murray and Riverina regions were experiencing near to or higher than normal plant greenness levels for the September to November period. Plant greenness levels remain lower than expected in western areas of the Murray and Riverina LLS regions. The impact of the 2019/2020 bush fires is still evident south of Tumut.

The time series charts (Figure 13) show the individual response of the drought indices for Hay, Finley, Temora and Moulamein. Temora and Finley remain steady with average to high soil water, plant growth and rainfall indices. Further rainfall is required at Hay and Moulamein to improve conditions. Variable, weak or delayed drought recovery has occurred in these areas due to lower rainfall during 2021.

The Combined Drought Indicator (CDI) is a tool that monitors drought conditions across NSW. The drought categories are based on assessing the response of three drought indicators: soil water, plant growth and rainfall. The indicators track the data over the past 12 months and show how the indices are tracking compared to long-term averages. The information provided in the map is aggregated to a Parish level and provides a regional assessment of conditions. Variability within and between farms is possible and this may not be reflected in the CDI map.

Western region

The Combined Drought Indicator (CDI, Figure 14) shows that drought conditions are variable across the region. Most of the region is in the Non-Drought or Recovering CDI category. The area in the Drought Affected category retracted during November as a result of recent rainfall. The DPI continues to closely monitor these recent improvements in Western LLS.

The seasonal NDVI anomaly data (Figure 15) shows variability across the Western LLS region. Much of the region is experiencing near normal or higher levels of plant greenness for the September to November period. Areas in the far west and south-west continue to have lower than normal plant greenness levels, along with parts of central Western LLS near Bourke.

The time series charts (Figure 16) show the individual response of the drought indices for Bourke, Ivanhoe and Wentworth. Ivanhoe remains in the Non-Drought category with high soil water, plant growth and rainfall indices. Continued rainfall is required at Bourke to maintain the Non-Drought status and improve the soil water and plant growth indices. Wentworth is currently in the Drought Affected category and rainfall is required to improve conditions. The time series chart for Broken Hill shows how the conditions can vary between months. The Broken Hill parish has recently entered the Non-Drought category due to recent rainfall however, it has been transitioning between the Drought and Non-Drought categories since January 2021. NSW continues to monitor the Western LLS region closely. To access a time series for your Parish, visit the Combined Drought Indicator website.

The Combined Drought Indicator (CDI) is a tool that monitors drought conditions across NSW. The drought categories are based on assessing the response of three drought indicators: soil water, plant growth and rainfall. The indicators track the data over the past 12 months. This shows how the indices are tracking compared to the long-term averages. The information provided in the map is aggregated to a Parish level and provides a regional assessment of conditions. Variability within and between farms is possible and this may not be reflected in the CDI map.

North West, Northern Tablelands and North Coast regions

The North West, Northern Tablelands and North Coast Local Land Service regions continue longer-term drought recovery. Productive conditions have generally been maintained due to rainfall received throughout the year. The Combined Drought Indicator (CDI, Figure 17) shows that the LLS regions are in the Non-Drought category.

Moderate to major flooding has occurred across some catchments during November. This flooding will impact crop yield potential for those winter crops that have not yet been harvested in these regions.

The seasonal NDVI anomaly data (Figure 18) indicated near to above-normal greenness across most of the regions for the September to November period.

The time series charts (Figure 19) show the individual response of the drought indices for Moree, Walgett, Tenterfield and Lismore. The indicators remain high at all locations. To access a time series for your Parish, visit the Combined Drought Indicator website.

The Combined Drought Indicator (CDI) is a tool that monitors drought conditions across NSW. The drought categories are based on assessing the response of three drought indicators: soil water, plant growth and rainfall. The indicators track the data over the past 12 months and shows how the indices are tracking compared to the long-term averages. The information provided in the map is aggregated to a Parish level and provides a regional assessment of conditions. Variability within and between farms is possible and this may not be reflected in the CDI map.

Central Tablelands, Central West, Hunter and Greater Sydney regions

The Central West, Central Tablelands, Hunter and Greater Sydney Local Land Services (LLS) regions remained in the Non-Drought Combined Drought Indicator (CDI) category in November (Figure 20). The regions remain in a strong position heading into the summer period, with average to above average soil water levels in many areas.

Moderate to major flooding has occurred across some catchments during November. This flooding will impact crop yield potential for those winter crops that have not yet been harvested in these regions. Recent heavy rainfall will likely impact crop quality in some horticultural areas.

The seasonal NDVI anomaly data (Figure 21) shows near normal to high levels of plant greenness across most of the LLS regions for the September to November period. The 2019/20 bushfire impact is still evident in parts of the Central Tablelands, lower Hunter and west of Greater Sydney.

The time series charts (Figure 22) show the individual response of the drought indices for Cowra, Condobolin and Singleton. Follow-up rainfall has supported the CDI indicators at all locations and there is evidence of a strong drought recovery. These regions currently remain well placed for productive conditions in the coming months.

The CDI is a tool that monitors drought conditions across NSW. The drought categories are based on assessing the response of three drought indicators: soil water, plant growth and rainfall. The indicators track the data over the past 12 months and show how the indices are tracking compared to the long-term averages. The information provided in the map is aggregated to a Parish level and provides a regional assessment of conditions. Variability within and between farms is possible and this may not be reflected in the CDI map.

South East region

The Combined Drought Indicator (CDI, Figure 23) shows that most of the South East Local Land Services region is in the Non-Drought CDI category. The South East LLS region remains well positioned as it heads into the summer period. The CDI shows that an area around Nowra is currently into the Recovery category. Further rainfall will continue to improve conditions in this region.

The seasonal NDVI anomaly data (Figure 24) showed near normal to high levels of plant greenness across most of the region for the September to November period. The areas impacted by the 2019/20 bushfires continue to have lower than average plant greenness levels.

The time series charts (Figure 25) show the individual response of the drought indices at Bega, Goulburn and Cooma. The three regions remain in the Non-Drought category with high soil water, plant growth and rainfall indices. These regions currently remain well placed for productive conditions in the coming months.

The Combined Drought Indicator (CDI) is a tool that monitors drought conditions across NSW. The drought categories are based on assessing the response of three drought indicators: soil water, plant growth and rainfall. The indicators track the data over the past 12 months and shows how the indices are tracking compared to the long-term averages. The information provided in the map is aggregated to a Parish level and provides a regional assessment of conditions. Variability within and between farms is possible and this may not be reflected in the CDI map.

Official national outlook

The official national outlook was released by the Bureau of Meteorology (BoM) on 02 December 2021. Rainfall during December to February is likely to be above median for most of eastern Australia. Western Tasmania and parts of Western Australia are likely to have below median rainfall. Elsewhere there is near equal chance of above or below median rainfall.

Maximum temperatures are likely to be above median for most of Australia. Below median maximum temperatures are likely for eastern New South Wales, south-east Queensland and far eastern Victoria. Minimum temperatures for December to February are likely to be above median across most of Australia. Parts of south-eastern Western Australia, western South Australia and north-east New South Wales have a near equal chance of above or below median minimum temperatures.

The Bureau issues a new 3-month seasonal update weekly, each Thursday afternoon.

NSW outlook

Most of NSW has a 60% to above 80% chance of receiving above median rainfall between December and February (Figure 26). The maximum temperature outlook indicates at 40% to above 80% chance of cooler than median temperatures across eastern NSW (Figure 27). There is a 60% to 80% chance of above median maximum temperatures in western NSW. There is a 60% to above 80% chance of warmer than median overnight temperatures across most of the state (Figure 28).

Global climate drivers

El Niño–Southern Oscillation (ENSO)

The Bureau of Meteorology’s (BoM) El Niño-Southern Oscillation (ENSO) Outlook was released on 23 November 2021. There is now an active La Niña established in the tropical Pacific Ocean. Climate models suggest that this La Niña will be short-lived, breaking down by early autumn 2022. La Niña typically increases the chance of above median rainfall in NSW during spring and summer.

Southern Oscillation Index

The 30-day Southern Oscillation Index (SOI) for the 30 days ending 21 November 2021 was +7.0. The 90-day SOI value was +8.6. Sustained negative values of the SOI below −7 typically indicate El Niño while sustained positive values above +7 typically indicate La Niña. Values between +7 and −7 generally indicate neutral conditions.

Sea surface temperatures (SST)

Sea surface temperatures (SST) in the central-to-eastern tropical Pacific Ocean have cooled over the past three months (Figure 30). Cool anomalies have also strengthened in the eastern equatorial Pacific Ocean. Warmer than average SSTs persist across the far western Pacific, including parts of the Maritime Continent and waters around northern Australia.

The latest values of the three NINO indices in the tropical Pacific for the week ending 21 November were: NINO3 -0.7°C, NINO3.4 -0.6°C, NINO4 -0.4°C. These values are in the ENSO neutral range but are expected to continue to cool.

Persistent NINO3 or NINO3.4 values warmer than +0.8 °C are typical of El Niño, while persistent values cooler than −0.8 °C typically indicate La Niña.

Sea sub-surface temperatures

The four-month sequence of equatorial Pacific sub-surface temperature anomalies (to 18 November) shows strong cold anomalies have persisted in the central to eastern equatorial Pacific Ocean during November. Sub-surface anomalies were 3-4ºC cooler than average in the eastern equatorial Pacific. Weak warm anomalies are present across parts of the water column in the western Pacific.

Indian Ocean (IOD)

The Indian Ocean Dipole (IOD) has returned to neutral in November 2021. All five international climate models surveyed by the Bureau of Meteorology indicate that the IOD will remain neutral in the coming months. This is consistent with the typical life cycle of an IOD event. The latest weekly value of the Indian Ocean Dipole (IOD) index to 29 November 2021 was −0.32 °C.

While the negative IOD has declined, warm SST anomalies persist to the northwest of Australia. A warmer eastern Indian Ocean in general may contribute to increased chances of above average spring rainfall for parts of southern and eastern Australia.

Southern Ocean (Southern Annular Mode – SAM)

The Southern Annular Mode (SAM) index is positive and is likely to remain mostly positive through the end of the year. A positive SAM typically increases the chance of above average rainfall for much of New South Wales during spring and summer.

The Southern Annular Mode (SAM) refers to the north-south shift of rain-bearing westerly winds and weather systems in the Southern Ocean compared to the usual position. This indicator can be quite volatile and generally influences weather conditions on 1-3 week timescales. SAM forecasts are highly uncertain beyond 2-3 weeks.

How does it work?

Much of the information in the Seasonal Conditions Report is sourced from the NSW DPI Enhanced Drought Information System (EDIS) ™. The EDIS system is currently available in prototype form and is subject to an intensive ground truthing process. For more information, visit the interactive website via DroughtHub.

EDIS is an ongoing project aimed at improving the quality and timeliness of efforts to monitor conditions across the state. Key features of the system are:

• It tracks drought by using four indicators; rainfall, soil water, plant growth, as well as tracing rainfall trends. Agronomic conditions have equal value to rainfall recorded at meteorological stations.
• The Combined Drought Indicator (CDI) brings this information together and has been designed to characterise developing drought conditions. The key purpose for building the CDI was as a drought early warning system.
• The rainfall, soil moisture and plant growth indicators in EDIS account for conditions over a 12-month window. This provides a compromise between a highly sensitive indicator (e.g. six months) and a less sensitive indicator (e.g. 24 months).
• Climate and remote sensing data drive the information system at a high resolution, but the CDI is reported at a Parish level.
• Because of its configuration and purpose, there will be differences to the indicator used in the National Drought Monitoring Framework (the Australian Rainfall Deficiency Analyser) which relies on rainfall alone.
• The CDI has three drought categories that characterise NSW according to drought intensity as well as the main drivers of a drought event (meteorological, hydrological and agronomic). DPI considers areas Drought Affected to be experiencing a drought event.
• The Drought Affected category encompasses a wide range of conditions from the very early stages of drought entry through to a drought event becoming intense. This enables the drought monitoring system to detect a drought event early. It is also possible to stay in the Drought Affected category for some period of time.

The way in which the indicators are combined to form the CDI is described in Table 1 below.

Table 1: Description of the Combined Drought Indicator framework

The NSW State Seasonal Update is provided each month by the NSW DPI Climate Branch.

Information used in this report was primarily sourced from the Australian Bureau of Meteorology, the US National Oceanic and Atmospheric Administration, the International Research Institute for Climate and Society (Columbia University), Geoscience Australia’s Digital Earth Australia Program, and NSW Department of Primary Industries.

Maps in this document contain data which is © Spatial Services – NSW Department of Finance, Services and Innovation (2021), Panorama Avenue, Bathurst 2795 and data which is © Commonwealth of Australia 2021, Australian Bureau of Meteorology, Melbourne. All rights reserved.

The seasonal outlooks presented in this report are obtained from the Australian Bureau of Meteorology and other sources (including World Meteorological Organisation Global Producing Centres). These outlooks are general statements about the likelihood (chance) of (for example) exceeding the median rainfall or minimum or maximum temperatures. Such probability outlooks should not be used as categorical or definitive forecasts, but should be regarded as tools to assist in risk management and decision making. Changes in seasonal outlooks may have occurred since this report was released.

All climate and remote sensing input data is supplied to the Enhanced Drought Information System ™ under the Australian Creative Commons Licence (CCY 4.0) and is made available by the Terrestrial Ecosystem Research Network.