NSW State Seasonal Update - November 2023

Prepared by NSW DPI

NSW overview

Despite significant rainfall towards the end of November, drought conditions continue for much of NSW.

• The NSW DPI Combined Drought Indicator (CDI) shows that 65% of NSW is in one of the three drought categories at the end of November.
• Despite the welcome rainfall, the decision-making environment remains a difficult one for many NSW farmers. Available remote sensing information of pasture conditions highlights that there is considerable variability within and between regions.
• Without follow up rainfall there is prospect that this could be a ‘false recovery’, or temporary respite from intensifying drought conditions.

Current conditions

• The late spring rainfall provided relief from drought conditions in areas like, North coast and Bega Valley, and to a lesser extent Hunter.
• The rainfall event has also slowed the drought onset and intensification that has been occurring across the state.
• The rainfall on the North Coast and some areas of the Hunter will boost pasture production and start to ease supplementary feeding programs over the coming weeks. Follow up rainfall over the coming months is critical in these regions for a sustained recovery from drought.
• The significant falls in the Bega valley will also ease drought conditions and boost water availability for irrigation in that part of NSW.
• Given late spring rainfall large areas in the west and south of the state are now in the Recovery category of the CDI, having spent a short period in the Drought Affected category in early November.
• Rainfall outlooks are largely neutral for the coming summer across most of NSW and temperatures likely to be well above historical median.

For further information on each Local Land Services region, see the Regional Breakdown section in this Update.

Seasonal Climate Outlook

The outlook is for very warm conditions across NSW and neutral chance of above median rainfall for much of NSW in the December to February period.

• The rainfall forecasts are variable for NSW, indicating there is a 40 – 65% chance of average rainfall for the November 2023 to January 2024 period.
• The ENSO Outlook status is at El Niño and the Southern Oscillation Index is negative.
• The Indian Ocean Dipole (IOD) is currently positive.
• Other climate drivers like the Southern Annular Mode (SAM) and local systems continue to bring the prospect of instability in week-to-week weather during this forecast period.

The CDI and its individual rainfall, soil moisture and crop/pasture growth metrics are leading biophysical indices of seasonal conditions and drought status. Other 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 NSW, 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.

Rainfall

Widespread rainfall during November

• Rainfall was variable across NSW during November (Figure 2a).
• Large areas of NSW received above 50mm of rainfall.
• Significant rain fell in parts of NSW over the last week of November 2023
  • There was in excess of 200mm in the southeast including flooding rain on the south coast of NSW.
  • High rainfall was also recoded in parts of the Riverina and Central West, with around 100mm recorded.
  • Rainfall across the Hunter and North coast of NSW was moderate with the weekly total ranging from as little as 5mm to around 60mm.
  • High intensity events have also been reported in isolated parts of NSW with flash flooding in centres like Deniliquin.

Calendar year to date rainfall is average to below average for many areas

• For the calendar year to date, eastern NSW has received between 300 to 1000mm of rainfall. Areas around the southern alpine region, and an isolated areas on the North Coast have received more than 1000mm. West of the Great Dividing Range has generally received rainfall between 100mm and 600mm (Figure 2b). Year to date rainfall has been average to very much below average for most of NSW.

Higher rainfall for much of NSW relative to long term records

• The November rainfall percentile map ranks the total for November 2023 in the range long term records from 1981-2020 (Figure 2c).
• November 2023 rainfall was in the top 80% of the historical record, given the significant event that occurred late in the month.  Areas like the southeast, parts of the Riverina and Northern NSW had falls in the 90-100% range (darker blue in Figure 2c).
• Parts of the Hunter and western NSW had minimal rainfall in November 2023 relative to long term expectations, with falls in the 20-40th percentile.

Temperature

Higher than average maximum temperatures for most of NSW

• In November, the average maximum temperatures ranged from 12°C in the southern alps to above 33°C in the northwest of NSW (Figure 3a).
• Above average maximum temperatures were experienced across most of NSW in November. Maximum temperatures were generally between 0°C and 3°C above average (Figure 3b).

Near average minimum temperatures for most of NSW

• Minimum temperatures were generally between 3°C and 18°C for most of NSW. The warmest temperatures (above 18°C) were in the far northwest of the state (Figure 3c).
• Minimum temperature anomalies were generally between -1 and 2°C for most of NSW during November (Figure 3d).

Normalised Difference Vegetation Index (NDVI) Anomaly

The NDVI anomaly at 23 November indicate large parts of north-west, central and coastal NSW have poor vegetation condition.

• The seasonal Normalised Difference Vegetation Index anomaly (NDVI, Figure 4) indicates that plant greenness levels are variable across NSW.
• Many areas had above normal plant greenness levels, particularly in the west and south of the state.
• Areas of below average plant greenness have continued across the Central West, Hunter, North West, South East, North Coast, Central Tablelands and Western Local Land Services areas.
• On ground reports support this observation, with low to very low ground cover being reported.
• The influence of recent rainfall on NDVI values at the end of November has not been included in this assessment.
• Some of the extremely negative NDVI areas (brown patches) are water bodies.

Decision support for drought feeding livestock

NSW Department of Primary Industries’ Drought & Supp Feed Calculator app has been re-released to support NSW livestock producers with their decision making as seasonal conditions change.

The Drought & Supp Feed Calculator simplifies decision making for livestock producers by enabling users to assess pastures and work out feed requirement and if supplementary feeding is needed, compare different supplements and ration mixes, and calculate the costs of different feeding options.

Search for Drought & Supp Feed Calculator and download the application from your app store.

NSW Farm Dam Survey

Water availability is highly variable across NSW

• The NSW Farm Dam Survey indicates dam levels have generally declined over the past few months (Figure 5).
• Higher farm dam levels are present across many parts of central and southern NSW.
• Low dam levels are evident along the NSW coast and hinterland. Large areas of Western NSW have dam levels below 60% capacity.
• The influence of recent rainfall on farm dam levels at the end of November has not been included in this assessment.
• The farm dam assessment was not possible for some parts of NSW in November due to missing data.

NSW DPI Farm Tracker Reports

NSW DPI Farm Tracker Application reports are completed by users across NSW. On the ground reports submitted on the NSW DPI Farm Tracker application (Figure 5b) show producers in several regions are reporting they are managing mild to severe drought conditions in November.

Tools for farmers to monitor and report seasonal conditions

The Farm Tracker application is freely available and can be used to help monitor seasonal conditions on your property. Completing a report allows a user to create a geotagged photo diary, monitor dam levels, or record changes at an individual paddock level.

This information provides a detailed and visual record of a farm over time that can be invaluable for budgeting, planning and decision making. The data collected for each farm is not available for other people to see or search.

Reports are also used by NSW DPI as a highly valuable information source to ground truth products from the DPI Seasonal Conditions Monitoring Program. Farmers data remains anonymous in this use.

Search for NSWDPI Farm Tracker and download the application from your app store.

Individual drought indicators

The individual indicators are being presented at a much finer resolution that in previous State Seasonal Updates. The maps now display the individual indicators at a 1km² gridded resolution. This allows readers to explore the indicator values (percentile scale 0-100) at a much higher level of detail.

The colour scale for each map transitions to a grey scale at the 30^th percentile. The 30^th percentile is one of the critical thresholds that DPI uses to monitor drought intensity (the threshold for Drought Affected). The grey scale also shows the 5^th percentile used to delineate Drought and IntenseDrought.

The Soil Water, Plant Growth and Rainfall indicators are all calculated by taking the mean of daily values over the last 12 months and ranking them relative to a 40-year baseline period. This configuration is used to detect moderate to severe drought events with a multiple season duration. The indicators track large changes and are not overtly sensitive to day-to-day or recent conditions over the past month conditions, so lag physical conditions in the field at the time of observation.

Soil Water Index

The Soil Water Index (SWI) shows conditions are variable across NSW.

• There is below average (below the 30th percentile) SWI values for most of central, northern and eastern NSW. Parts of western NSW also have below average SWI values.
• There has been a slight improvement in the SWI over the past few weeks for parts of the North Coast and Northern Tablelands, Hunter and Wollongong region due to recent rainfall events.
• Areas of southern and western NSW continue to have near average to above average (percentile range – 50-80%) root zone SWI values.
• Substantial rainfall in many areas is needed to trigger an improvement in the SWI.

Plant Growth Index

Plant Growth Index values continue to decline.

• The Plant Growth Index (PGI, Figure 7) shows a decline across all of NSW since the October Update.
• The Plant Growth Index shows that conditions are variable across NSW and display a similar pattern to the SWI values.
• There is below average (below the 30th percentile) for most of central, northern and eastern NSW.
• Substantial follow up rainfall over the coming weeks and conditions that aid plant growth is needed to trigger a substantial improvement in the PGI.

Rainfall Index

Rainfall Index values remain variable.

• The Rainfall Index (RI) is variable across the state (Figure 8).
• Most of central northern and eastern NSW have RI values below average (below the 30th percentile) to very below average (below the 5th percentile).
• Recent rainfall has resulted in the improvement in the RI values across many parts of NSW. However further rainfall is needed to maintain or improve conditions.

Drought Direction Index

Drying trend continues for most of NSW.

• The Drought Direction Index (DDI, Figure 9) tracks the 150-day trend of the rainfall index.
• Most of NSW is showing either a weak or strong drying trend due to below average rainfall over the past few months.
• This trend, combined with the decline in the individual drought indicators reflects the deterioration of conditions and the onset or continuation of a major drought in these regions over recent months.

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

NSW outlook – December 2023 to February 2024

(issued 30 November 2023)

Neutral rainfall outlook for most of NSW

• The seasonal rainfall outlook indicates that there is a near equal chance (between 45% to 60%) of above median rainfall for most of NSW during the December to February period (Figure 10).
• There is a 30-55% chance of above median rainfall for some coastal areas in the south and north, as well as parts of central and north western NSW.

Warm to hot conditions  to continue for NSW 

• The maximum temperature outlook indicates a 70 to above 80% chance of exceeding median daytime temperatures across NSW during the forecast period (Figure 11).
• There is an above 80% chance of warmer than median overnight temperatures across all of NSW during the forecast period (Figure 12).

Prospect of unstable weather

• Although the rainfall outlook is neutral for most of NSW with warmer temperatures across the state, other climate drivers like the Southern Annular Mode (SAM), individual weather systems and warm local sea surface temperatures bring the prospect of unstable week to week weather during the forecast period.
• It is important to continue to check medium range (2 week) and short range (3-1 day) weather forecasts.

Official national outlook

The official national outlook was released by the Bureau of Meteorology on 30 November 2023.

The rainfall outlook for December to February shows that there is a 20 to 40% chance of above median rainfall for most of western and northern Australia. Large parts of inland Australia have a near equal chance of above or below median rainfall.

Maximum temperatures for December to February have a very likely chance (greater than 80%) of being warmer than average for most of Australia.

Minimum temperatures for the December to February period have a likely to very likely (60% to 80%) chance of being warmer than average for most of Australia.

Forecast accuracy at this time of year has generally been moderate to high for most of Australia. The Bureau issues a new 3-month seasonal update weekly, each Thursday afternoon.

Global climate drivers

El Niño–Southern Oscillation (ENSO)

The Bureau of Meteorology’s El Niño-Southern Oscillation (ENSO) Outlook was released on 5 December 2023. The ENSO Outlook status is at El Niño and tracking around moderate strength.

Sea surface temperatures (SSTs) in the tropical Pacific Ocean continue to exceed El Niño thresholds. Atmospheric indicators over the Pacific continue to reflect El Niño conditions. The Southern Oscillation Index (SOI) is negative. Models indicate that the El Niño is likely to persist into early autumn 2024.

Southern Oscillation Index

The 30-day Southern Oscillation Index (SOI; Figure 13) for the 30 days ending 01 December was -8.1. The 90-day SOI value (as of 3 December) was -9.1. Sustained negative values of the SOI below −7 typically indicate El Niño while sustained positive values above +7 typically indicate La Niña.

Sea surface temperatures (SST)

Monthly sea surface temperatures (SST) were warmer than average across most of the tropical Pacific Ocean (Figure 14). Warm SST anomalies persist along parts of the Australian coastline, particularly the southeast and Tasmania. Warm anomalies also remain in the southern Tasman Sea.

The latest values of the three NINO indices in the tropical Pacific for the week ending 3 December were: NINO3 +1.69 °C, NINO3.4 +1.77 °C, NINO4 +1.60 °C (sourced from the Bureau of Meteorology on 5 December 2023).

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.

Sub-surface sea temperatures

The four-month sequence of equatorial Pacific sub-surface temperature anomalies (to 23 November 2023) shows warm anomalies across most of the Pacific basin for the top 100m in depth, except the far west, which has cooled further since the October update (Figure 15). These warm anomalies reached more than 2.5⁰C above average for the eastern Pacific.

Indian Ocean (IOD)

A positive Indian Ocean Dipole (IOD) continues. The latest weekly value of the Indian Ocean Dipole (IOD) index to 3 December 2023 was +1.20°C. The weekly index values for this positive IOD event are the second highest since records for the Bureau SST dataset began in 2001.

All the international climate models surveyed by the Bureau of Meteorology suggest a positive IOD event is likely to ease in December. A positive IOD can suppress winter and spring rainfall over much of Australia, including NSW. When a positive IOD and El Niño occur together, their drying effect is typically stronger and more widespread across Australia.

Southern Ocean (Southern Annular Mode – SAM)

The Southern Annular Mode (SAM) index currently neutral (as of 5 December).

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 their usual position. This indicator can be quite volatile and generally influences weather conditions on 1 to 3 week timescales. A neutral SAM has little influence on Australian rainfall.

CDI status for the regions

Figure 17 displays the CDI status for each individual Local Land Services (LLS) region to 30 November 2023. The following regional descriptions are based on data available until the end of November 2023.

Murray and Riverina regions

The production outlook continues to remain positive heading into summer.

• Most of the Murray and Riverina Local Land Services (LLS) region remains in the Non-Drought category at the end of November (CDI, Figure 18).
• Parts of the Murray and Riverina regions transitioned into the Drought Affected category during November. Many areas that were in this category transitioned into the Recovery category at the end of November due to recent rainfall easing conditions.
• Further rainfall is needed to ensure this is not a ‘false recovery’ and that areas do not transition back into one of the drought categories.
• November rainfall was variable, with above average rainfall being recorded across the region. This may have impacted on-farm operations, particularly those harvesting winter crops. Deniliquin received the highest November rainfall on record for November.
• The seasonal NDVI anomaly data (Figure 19) shows that levels of plant greenness were variable across the region. Most areas continue to experience normal to higher than normal plant greenness levels. The areas with below average levels of greenness have expanded over the past month and indicate low levels of ground cover and standing dry matter available for livestock.
• Some of the extremely negative NDVI areas (brown patches) represent water. The influence of recent rainfall on NDVI values at the end of November has not been included in this assessment.

Drought indicators have responded to November rainfall across the regions.

• The Drought History charts (Figure 20) show the individual response of the drought indicators for Finley, Moulamein, Hay and Temora.
• The indicators have responded well at all locations due to the November rain over the past month.
• Follow up rainfall in the coming weeks will be needed to ensure conditions continue to improve.
• Producers continue to monitor conditions closely in conjunction with forecasts and outlooks.
• To access a Drought History chart for your Parish, visit the Seasonal Conditions Information Portal.

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.

Figure 18. Combined Drought Indicator for the Murray and Riverina regions

Figure 19. NDVI anomaly map for the Murray and Riverina LLS regions

Western region

Western region producers are monitoring their local seasonal conditions and forecasts closely in line with their production systems.

• The Combined Drought Indicator (CDI, Figure 21) shows that approximately 65% of the Western LLS region is currently in the Drought Affected category.
• Conditions declined during November and the extent of the region in drought expanded since the October Update.
• November rainfall was near average to above average across most of the region. Higher than average rainfall was recorded in the east of the region.
• Parts of the region are currently in the Recovery category. These regions transitioned into the Drought Affected category during November, however recent rainfall has helped ease conditions. Further rainfall is needed to ensure this is not a ‘false recovery’ and that areas do not transition back into one of the drought categories.
• The seasonal NDVI anomaly data (Figure 22) shows that levels of plant greenness were variable across the region. Most areas continue to experience normal to higher than normal plant greenness levels. The areas with below average levels of greenness have expanded over the past month and indicate low levels of ground cover and standing dry matter available for livestock.
• Some of the extremely negative NDVI areas (brown patches) represent water. The influence of recent rainfall on NDVI values at the end of November has not been included in this assessment.

Drought indicators are declining in many areas but have responded to November rainfall

• The Drought History charts (Figure 23) show the individual response of the drought indicators for Bourke, Ivanhoe, Wentworth, and Broken Hill.
• The indicators remain strong at Ivanhoe and Wentworth, in response to rainfall in November.
• Bourke has seen a slight improvement in the indicators and has recently transitioned into the Drought Affected category (from the Drought category). Follow up rainfall in the coming weeks will be needed to ensure conditions continue to improve.
• The Broken Hill parish has transitioned to the Recovery category from the Drought Affected category. Substantial rainfall is needed to ensure conditions continue to improve.
• Producers continue to monitor conditions closely in conjunction with forecasts and outlooks.
• To access a Drought History chart for your Parish, visit the Seasonal Conditions Information Portal.

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.

Figure 21. Combined Drought Indicator for the Western LLS region

Figure 22. 3-month NDVI anomaly map for the Western region

North West, Northern Tablelands and North Coast regions

Drought conditions have eased slightly in some areas, with producers continuing to focus on short to medium term management strategies for their productions systems, especially livestock welfare, water, and feed availability.

• The Combined Drought Indicator (CDI, Figure 24) shows the region is in one of the drought categories at the end of November.
• The late spring rainfall provided relief from drought conditions and has slowed the drought onset and intensification that has been occurring across the region. The rainfall will boost pasture production and ease supplementary feeding programs over the coming weeks. However further rainfall is needed to ensure longer term improvement in conditions and to see the start of a sustained recovery from drought.
• The seasonal NDVI anomaly data (Figure 25) shows that levels of plant greenness were variable across the region. The areas that have below average levels of greenness has expanded over the past month and indicate low levels of ground cover and standing dry matter available for livestock.
• Some of the extremely negative NDVI areas (brown patches) represent water. The influence of recent rainfall on NDVI values at the end of November has not been included in this assessment.
• On ground reports suggest that some producers will continue to supplementary feed stock as part of their drought management strategy.
• The NSW DPI continues to closely monitor conditions in these regions.

Drought indicators are in decline in all regions consistent with the continuation of a drought event.

• The Drought History charts (Figure 26) show the individual response of the drought indicators for Tenterfield, Moree, Walgett, and Lismore.
• There has been a positive response in the indicators at all locations due to recent rainfall. The rainfall has seen Walgett and Tenterfield transitioned from the Drought category into the Drought Affected category. Moree remains the Drought Affected category. Lismore transitioned from the Intense Drought category into the Drought category.
• Despite recent improvements in the indicators, follow up rainfall in the coming weeks will be needed to ensure conditions continue to improve.
• To access a Drought History chart for your Parish, visit the Seasonal Conditions Information Portal.

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.

Figure 24.  Combined Drought Indicator for the North West, Northern Tableland and North Coast regions

Figure 25. 3-month NDVI anomaly map for the North West, Northern Tableland and North Coast regions

Central Tablelands, Central West, Hunter and Greater Sydney regions

Drought conditions continue to impact the regions.

• The Combined Drought Indicator (CDI, Figure 27) shows most regions being in one of the drought categories at the end of November.
• Recent rainfall has helped ease drought conditions in some areas, with producers seeing an improvement in ground cover. However further rainfall in the coming weeks is needed to trigger long term improvement in conditions.
• Conditions have declined further in the Upper Hunter, with a large area in the Intense Drought Category
• The seasonal NDVI anomaly data (Figure 28) shows that levels of plant greenness were variable across the region. The areas that have below average levels of greenness has expanded over the past month and covers much of the region. This indicates low levels of ground cover and standing dry matter available for livestock.
• Some of the extremely negative NDVI areas (brown patches) represent water. The influence of recent rainfall on NDVI values at the end of November has not been included in this assessment.
• On ground reports suggest that some producers are continuing to supplementary feed stock as part of their drought management strategy as pastures recover.
• The NSW DPI continues to closely monitor conditions in these regions.

Drought indicators remain low.

• The Drought History chart (Figure 29) show the individual response of the drought indicators for Cowra, Condobolin and Singleton.
• Indicators at Condobolin have stabilised over the past few weeks.
• Recent rainfall at Cowra has seen this area move out of the Drought Affected category.
• There has been a stabilisation of the CDI indicators at Singleton with the region remaining the in Drought Affected category.
• Further rainfall in the coming weeks is needed to ensure conditions continue to improve across the regions.
• To access a Drought History chart for your Parish, visit the Seasonal Conditions Information Portal.

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

Drought conditions continue for parts of the South East region.  

• The Combined Drought Indicator (CDI, Figure 30) shows approximately 65% of the region in one of the drought categories.
• November rainfall was above average across the region, with significant rainfall occurring in the last week of November for some areas.
• This rainfall has provided some short-term relief to drought conditions, and placed some areas in the Recovery category. For other areas it has reduced the intensity of drought, such as the Bega Valley, which has been managing drought conditions for many months.
• Further rainfall is needed to help maintain conditions and ensure this is not a ‘false recovery’.
• The seasonal NDVI anomaly data (Figure 31) shows that levels of plant greenness were variable across the region. The areas that have below average levels of greenness has expanded over the past month and covers much of the region. This indicates low levels of ground cover and standing dry matter available for livestock.
• Some of the extremely negative NDVI areas (brown patches) represent water. The influence of recent rainfall on NDVI values at the end of November has not been included in this assessment.
• The NSW DPI continues to closely monitor conditions in this region.

Drought indicators continue to remain low across the region.

• The Drought History charts (Figure 32) show the individual response of the drought indicators at Bega, Cooma and Goulburn.
• There has been a rapid increase in the rainfall indicator at all locations due to the significant rainfall event that impacted the South Coast LLS region at the end of November. However, follow up rainfall in the coming weeks will be needed to ensure conditions continue to improve for all indicators.
• Producers in these areas should monitor local conditions closely and on ground reports suggest that many producers are implementing drought management strategies in line with their production systems.
• To access a Drought History chart for your Parish, visit the Seasonal Conditions Information Portal.

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.

Figure 30. Combined Drought Indicator for the South East region

Figure 31. 3-month NDVI anomaly map for the South East region

How does it work?

The Combined Drought Indicator is one source of information that informs policy and Government responses to changing seasonal conditions, including drought. The map provides a snapshot of conditions at a point in time and is not used to determine eligibility for drought assistance measures offered by the NSW Government.

Much of the information in the Seasonal Conditions Report is sourced from the NSW DPI Enhanced Drought Information System (EDIS)™. The EDIS system is subject to an intensive ground truthing process. For more information, visit the interactive website via droughthub.nsw.gov.au.

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 National University, 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 (2023), Panorama Avenue, Bathurst 2795 and data which is © Commonwealth of Australia 2023, Australian Bureau of Meteorology, Melbourne, and © Australian National University. 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.