NSW State Seasonal Update - June 2023

Prepared by NSW DPI

NSW overview

The NSW DPI Combined Drought Indicator (CDI) shows 99% of NSW in the Non-Drought category at the end of June. Despite variable rainfall in June, the production outlook continues to remain strong for most areas of NSW. There are regions that are managing feed deficits, particularly in the northern NSW and Hunter regions.

Current conditions

• June rainfall was variable, concentrated largely in southern and western NSW.
• Dry conditions continue to impact parts of the state leading to a decline in plant growth in the north, north-east, and south-east. On ground reports suggest that some areas are managing feed deficits. The DPI continues to closely monitor conditions.
• Subsoil moisture levels for NSW are mostly average to above average, generally drier in the north-east, far south-east and north-west of the state.
• Water availability for irrigated production remains adequate, with many irrigation schemes at near full capacity.

Seasonal Climate Outlook

• Seasonal climate forecasts indicate warmer than average days and warmer than average overnight temperatures for most of NSW for the July to September period.
• Rainfall is likely to be below average for most of inland NSW from July to September.
• The ENSO Outlook status is at El Niño ALERT, indicating a 70% chance of El Niño forming over the coming months.
• The Indian Ocean Dipole (IOD) is currently neutral; models suggest a positive IOD event, may occur in the coming months. A positive IOD event is normally associated with below median rainfall. Long range forecasts of the IOD beyond August should be viewed with caution.

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

The rainfall anomaly data shows the difference between total monthly rainfall and the long-term average monthly rainfall (1981 – 2010; Figure 2a). Eastern NSW has recorded negative rainfall anomalies for June. The highest negative anomalies were recorded along some coastal regions of NSW. Positive rainfall anomalies were recorded for large parts of the Western, Riverina and Murray Local Land Services (LLS) regions.

Rainfall was variable during June. The highest monthly rainfall totals (above 100mm) were recorded in the southern Alpine regions of NSW. (Figure 2b). Large areas of Riverina, Murray and Western NSW received totals above 50mm. Eastern NSW received generally between 10 and 50mm of rainfall over the month, while some parts of eastern NSW received less than 10mm of rainfall.

For the calendar year to date, eastern NSW has received between 200 to above 600mm of rainfall. Areas around Coffs Harbour, Taree, Lismore and the southern highlands have received more than 600mm. West of the Great Dividing Range has generally received rainfall between 50mm and 400mm (Figure 2c). Year to date rainfall has been average to below average for most of NSW.

Temperature

Near average maximum temperatures were experienced across most of NSW in June (Figure 3a). Maximum temperatures were generally 1°C above average in parts of the North Coast, North West and Western Local Land Services regions. In June the average maximum temperatures ranged from 0°C in the southern alps to above 21°C in north-eastern NSW (Figure 3b).

Minimum overnight temperatures were near average across most of NSW during June. Minimum temperatures were more than 2°C below average along parts of the North Coast and 1°C warmer than average in western and southern NSW (Figure 3c). The average June minimum temperatures (Figure 3d) ranged between -3°C to 0°C in the alps and Tablelands. Western NSW and parts of the east coast recorded average minimum temperatures of above 6°C.

The alpine and tableland regions (between Tamworth and Armidale) experienced the highest number of frost days during June (Figure 3e).

Normalised Difference Vegetation Index (NDVI) Anomaly

The seasonal Normalised Difference Vegetation Index (NDVI, Figure 4) indicates that plant greenness levels are variable across NSW. Many areas continue to have above normal plant greenness levels due to recent rainfall aiding plant growth. Near normal to lower than normal levels of plant greenness are present for large areas of the Central West, Hunter, North West and Western Local Land Services areas. Small, isolated patches of lower than average plant greenness are occurring across NSW. Some of the extremely negative NDVI areas (brown patches) are water bodies.

NSW Farm Dam Survey

The NSW Farm Dam Survey indicates dam levels are generally 60% or less of capacity across large areas NSW (Figure 5). Regions west of the Great Dividing Range and parts of northern and coastal NSW maintain farm dam levels at less than 40% of capacity. Data is unavailable for some areas of NSW due to cloud cover.

Soil Water Index

The Soil Water Index (SWI, Figure 6) shows conditions continued to decline during June. The areas in the Average SWI category have expanded since the last Update, particularly in the Hunter, Central Tablelands and northern NSW. The area west of Grafton in the Below Average category has expanded, along with areas south-west of Lismore, east of Narrabri and Bega. This is due to the continued low and variable rainfall received this year.

Plant Growth Index

The Plant Growth Index (PGI, Figure 7) shows that most of NSW remains in the Average to Above Average PGI category. The Average and Below Average categories have expanded during June with parts of Western, central and eastern NSW transitioning into one of these categories.

Rainfall Index

The Rainfall Index (RI, Figure 8) shows that the area in the Extremely High category has expanded slightly in June, particularly in the Western and Riverina LLS Regions. The reminder of the state falls in the Average to Above Average category, except for areas on the North Coast and east of Singleton which are in the Below Average to Extremely Low categories.

Drought Direction Index

The Drought Direction Index (DDI, Figure 9) tracks the 150-day trend of daily rainfall totals. Western NSW is generally showing a wetting trend due to recent rainfall during May and June. In contrast, much of eastern and northern NSW have recorded a strong drying trend during June. A weak drying trend has been recorded for most of central NSW. Areas in the Weak Drying Trend category have experienced a slightly drier May and June compared to previous months. A strong drying trend along the east coast and northern tablelands has been influenced by high rainfall recorded in late 2022, and the comparatively drier conditions over the last few months.

Changes in the individual drought indicators may have occurred since this update was released.

NSW outlook - July to September

(issued 4 July 2023)

Average to below average rainfall for much of NSW

• The rainfall outlook for July indicates near average rainfall for most of NSW, and above average rainfall likely in the north-east and north-west of NSW (60% to 70% chance).
• The seasonal rainfall outlook indicates that there is a 45% to 70% chance of below median rainfall across most of NSW during the July to September period (Figure 10).
• Parts of the Murray and Riverina have a greater than 70% of below median rainfall during the July to September period.
• Slightly above median rainfall is likely (55% to 60% chance) for a small region in the far north east of NSW.

High chance of warmer days for NSW

• The maximum temperature outlook indicates a more than 75% chance of exceeding median daytime temperatures across NSW during the July to September period (Figure 11).

Warmer nights across NSW

• There is an above 80% chance of warmer than median overnight temperatures across most of eastern, central and southern NSW during the July to September period (Figure 12).
• Across western NSW there is a 65% to above 80% chance of above median overnight temperatures.

Official national outlook

The official national outlook was released by The Bureau of Meteorology on 29 June 2023.

The rainfall outlook for July to September shows that most of Australia has a likely to very likely (60% to 80%) chance of below median rainfall. Above median rainfall is likely for parts of the Northern Territory and far North Queensland.

Maximum temperatures for July to September have a likely to very likely (60% to greater than 80%) chance of being warmer than average for most of Australia.

Minimum temperatures for the July to September period have a likely to very likely (60% to greater than 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 04 July 2023. The ENSO Outlook status is currently at El Niño ALERT. Central and eastern Pacific sea surface temperatures (SSTs) are exceeding El Niño thresholds. However atmospheric indicators (E.g., trade winds, cloudiness) have not reached El Niño thresholds. The Southern Oscillation Index (SOI) is at neutral levels. This means the Pacific Ocean and atmosphere have yet to become fully coupled, as occurs during El Niño events.

Models indicate a high likelihood of further warming, with SSTs exceeding El Niño thresholds until at least the beginning of the southern hemisphere summer. El Niño typically suppresses winter–spring rainfall in eastern Australia. The Bureau of Meteorology’s El Niño ALERT indicates a 70% chance of El Niño occurring in 2023.

Southern Oscillation Index

The 30-day Southern Oscillation Index (SOI; Figure 13) for the 30 days ending 02 July was +1.1. The 90-day SOI value as of 21 May was -5.5. Both the 30-day and 90-day continue to show a gradual declining trend.

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 the eastern and western tropical Pacific Ocean (Figure 14). Warm SST anomalies persist in the southern Tasman Sea, from south-east Australia to New Zealand.

The latest values of the three NINO indices in the tropical Pacific for the week ending 02 July were: NINO3 +1.49 °C, NINO3.4 +0.94 °C, NINO4 +0.63 °C (sourced from the Bureau of Meteorology on 4 July 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.

Sea sub-surface temperatures

The four-month sequence of equatorial Pacific sub-surface temperature anomalies (to 3 June 2023) shows warm anomalies across most of the Pacific basin for the top 175m in depth (Figure 15). These warm anomalies reached more than are more than 3^oC above average for most of the region.

Indian Ocean (IOD)

The Indian Ocean Dipole (IOD) is currently neutral. The latest weekly value of the Indian Ocean Dipole (IOD) index to 2 July 2023 was -0.21 °C.

All of the international climate models surveyed by the Bureau of Meteorology suggest a positive IOD may emerge in the coming months. A positive IOD occurs at values greater than +0.4 °C and can suppress winter and spring rainfall over much of Australia, including NSW. Long range IOD forecasts beyond August should be viewed with caution.

Southern Ocean (Southern Annular Mode – SAM)

The Southern Annular Mode (SAM) index is negative (as of 1 July) and is expected to return to neutral values over the next three weeks (Figure 16).

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 June 2023. The following regional descriptions are based on data available until the end of June 2023.

Murray and Riverina regions

The Combined Drought Indicator (CDI, Figure 18) shows that all of the Riverina and Murray Local Land Services (LLS) regions remain in the Non-Drought category at the end of June. June rainfall was generally average to above average for most of the region. Areas in the central and west have low farm dam levels while areas in the east are generally experiencing high to very high farm dam levels.

The seasonal NDVI anomaly data (Figure 19) shows that most of the Murray and Riverina regions, were experiencing normal to higher than normal plant greenness levels for the April to June period. Some of the extremely negative NDVI areas (brown patches) represent water.

The Drought History charts (Figure 20) show the individual response of the drought indicators for Hay, Temora, Finley, and Moulamein. The indicators are high at all locations and suggest a strong production outlook. 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.

Western region

The Combined Drought Indicator (CDI, Figure 21) shows that the Western LLS region is currently in the Non-Drought category. June rainfall was average to above average for most of the Western region. Farm dam levels are variable with some regions having low farm dam levels while other areas are experiencing high to very high farm dam levels due to recent flooding. The DPI continues to closely monitor conditions in Western LLS.

The seasonal NDVI anomaly data (Figure 22) shows normal to very high levels of plant greenness across most of the Western LLS region for the April to June period. Below normal levels of greenness are apparent in the north-west and northern areas of the LLS region. Some of the extremely negative NDVI areas (brown patches) represent water.

The Drought History charts (Figure 23) show the individual response of the drought indicators for Bourke, Ivanhoe, Wentworth, and Broken Hill. Although still high, the rainfall, soil water and plant growth indicators have declined at Bourke and Broken Hill. Indicators remain high at Ivanhoe and Wentworth. 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.

North West, Northern Tablelands and North Coast regions

The Combined Drought Indicator (CDI, Figure 24) shows most of the region is in the Non-Drought category at the end of June. The areas in the Drought Affected category around Grafton and Lismore has slightly expanded since the May Update. The Drought Affected area near Narrabri and Tweed Heads remains stable. June rainfall was generally average to below average for the three Local Land Services regions and farm dam water levels are variable.

The seasonal NDVI anomaly data (Figure 25) indicates that parts of the region have average to below average levels of plant greenness for the April to June period. Some of the extremely negative NDVI areas (brown patches) represent water. The NSW DPI continues to closely monitor conditions in these regions.

The Drought History charts (Figure 26) show the individual response of the drought indicators for Tenterfield, Moree, Walgett, and Lismore. There has been a decline in the plant growth and soil water indicators at Moree. Indicators have continued to decline at Tenterfield, Lismore, and Walgett. The sharp declines are likely due to below average rainfall received for the calendar year to date and last year’s record rainfall no longer being included in the indicator calculations. On ground reports indicate that some areas are managing feed deficits and a reduction in stored soil moisture. Further rainfall is required to maintain productive conditions. These regions should continue monitor conditions closely. 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.

Central Tablelands, Central West, Hunter and Greater Sydney regions

The Combined Drought Indicator (CDI; Figure 27) shows that the Central West, Central Tablelands, Hunter and Greater Sydney Local Land Services (LLS) regions continue to experience Non-Drought conditions at the end of June. A small area in the Hunter LLS region has transitioned into the Drought-Affected category. June rainfall was average to below average for the Central Tablelands, Hunter and Greater Sydney LLS regions. Parts of the Central West LLS region experienced above average rainfall. Farm dam water levels are variable across the four LLS regions.

The seasonal NDVI anomaly data (Figure 25) indicates near normal levels of greenness across most of the regions for the April to June period. Parts of the Central West around Coonamble, and the north-west of the Hunter LLS region have below average levels of greenness. On ground reports indicate that some regions are managing feed deficits and a reduction in stored soil moisture. Some of the extremely negative NDVI areas (brown patches) represent water. The NSW DPI continues to closely monitor conditions in these regions.

The Drought History charts (Figure 29) show the individual response of the drought indicators for Cowra, Condobolin and Singleton. There has been a decline in the CDI indicators at Singleton however, the CDI indicators are currently high at all locations. 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

The Combined Drought Indicator (CDI, Figure 30) shows that most of the South East Local Land Services region is in the Non-Drought CDI category. There is a small area that has transitioned to the Drought Affected category since the May Update. June rainfall was average to below average for most of the region and farm dam water levels are variable although data is missing due to cloud cover affecting satellite imagery during the reporting period.

The seasonal NDVI anomaly data (Figure 31) shows near normal to above average levels of plant greenness across most of the region. There are areas that have below average levels of greenness. Some of the extremely negative NDVI areas (brown patches) represent water. The NSW DPI continues to closely monitor conditions in this region. The white patches represent missing data.

The Drought History charts (Figure 32) show the individual response of the drought indicators at Bega, Cooma and Goulburn. Indicators remain steady at Cooma and Goulburn. There has been a steady decline in all indicators at Bega over the past few months. Further rainfall is required to maintain productive conditions. The NSW DPI continues to closely monitor conditions in this region. To access a Drought History chart for your Parish, visitthe 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.

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.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.