NSW State Seasonal Update - January 2023

Prepared by NSW DPI

NSW overview

New South Wales continues to experience a strong production outlook despite variable rainfall across the state this month. The NSW DPI Combined Drought Indicator (CDI) shows 100% of NSW in the Non-Drought category at the end of January.

Soil water and plant growth have remained high across the state, despite the combination of variable rainfall in January following on from comparatively drier conditions in December. Pasture availability remains high in many regions although the nutritional value of pasture for livestock has declined over recent months. There have been opportunities in many parts of the state to conserve fodder. The summer cropping season continues across NSW. On ground reports suggest some cropping enterprises had a delayed start due to wetter and cooler conditions.

Water availability for production remains strong, with many on-farm dam levels and irrigation schemes at full capacity. However, average to below average rainfall in December and January has seen dam levels fall in some areas particularly in the north and northwest of the state.

Seasonal climate forecasts indicate warmer than average days in the north, west and southeast of NSW, and cooler than average day time temperatures in parts of eastern NSW for the March to May period. Overnight temperatures are likely to be warmer than average in eastern NSW during this period. Rainfall is likely to be average to below average across most of NSW between March to May. The ENSO Outlook status is at La Niña. The Indian Ocean Dipole (IOD) is neutral, with a low likelihood of influencing Australian climate in the next few months.

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). Near average rainfall has been received across most of NSW in January. The highest negative rainfall anomalies were recorded in parts of the North West, Northern Tablelands, North Coast, and Central West LLS regions. The highest positive rainfall anomalies were observed in parts of the Riverina and Murray LLS regions, particularly around Albury.

The highest monthly rainfall totals in January were recorded in parts of southern and eastern parts of NSW where rainfall of more than 100mm was received (Figure 2b). Most of NSW received above 25mm of rainfall in January.

Temperature

Near average maximum temperatures were experienced across most of NSW in January. Maximum temperatures were 1 to 2 degrees below average in eastern NSW (Figure 3a). In January the average maximum temperatures ranged from 15°C in the southern alps to above 36°C in northwestern NSW. Most of central NSW experienced day time temperatures above 30°C, except for parts at higher altitudes. Parts of the Tablelands and southeast NSW experienced average day time temperatures below 24°C (Figure 3b).

Minimum overnight temperatures were average for most of NSW in January. Temperatures were 1 to 2 degrees below average across parts of central and north-eastern NSW (Figure 3c). The average January minimum temperatures (Figure 3d) ranged between 6°C to 12°C in the Alpine and Tablelands. The far northwest of NSW recorded the highest average minimum temperatures of above 24°C.

Normalised Difference Vegetation Index (NDVI) Anomaly

The seasonal Normalised Difference Vegetation Index (NDVI, Figure 4) indicates that plant greenness levels are normal to well above normal across most of NSW for the November to January period. 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 greater than 40% of capacity across central and eastern NSW (Figure 5). Large areas of the Western LLS region, particularly along the Darling River, have dam levels at greater than 80% capacity. 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 that most of NSW is currently in the extremely high category. Soil water conditions have moved into the above average category in parts of eastern and northern NSW due to the low and variable rainfall received in December and January.

Plant Growth Index

The Plant Growth Index (PGI, Figure 7) shows that most of NSW is in the extremely high category at the end of January due to the high Spring rainfall. Some areas of eastern NSW show an average to above average PGI due to the lower December and variable January rainfall and warm summer temperatures.

Rainfall Index

The Rainfall Index (RI, Figure 8) for 2023 shows that at the end of January most of NSW is in the extremely high category. Drier December conditions and variable rainfall in January have led to areas moving back into average to above average RI values.

Drought Direction Index

The Drought Direction Index (DDI, Figure 9) tracks the 150-day trend of daily rainfall totals. The DDI shows a strong drying trend throughout most of NSW. Both weak wetting and drying trends can be seen in parts of northwestern and eastern NSW. The drying trends are a result of extremely high rainfall recorded in 2022 and the comparatively drier conditions in the few last months. Importantly the weak to strong drying trend does not indicate the emergence of a drought in the regions, rather it indicates a degree of drying following on from the previous very wet conditions.

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

Murray and Riverina regions

The Combined Drought Indicator (CDI, Figure 11) shows that all of the Riverina and Murray Local Land Services (LLS) regions remain in the Non-Drought category at the end of January.

The seasonal NDVI anomaly data (Figure 12) shows that parts of the Murray and Riverina regions were experiencing higher than normal plant greenness levels for the November to January period. Some of the extremely negative NDVI areas (brown patches) represent water.

The Drought History charts (Figure 13) show the individual response of the drought indices for Hay, Temora, Finley, and Moulamein. The indicators are high at all locations and suggest a strong outlook to the start of autumn. 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 14) shows that the Western LLS region is currently in the Non-Drought category. Continued rainfall throughout the region in January has maintained flood risk warnings for the Darling and Lachlan rivers.

However, rainfall has not been uniform and some parts currently have low farm dam levels. Other regions are experiencing high to very high farm dam levels. The DPI continues to closely monitor conditions in Western LLS.

The seasonal NDVI anomaly data (Figure 15) shows normal to very high levels of plant greenness across the Western LLS region for the November to January period. Some of the extremely negative NDVI areas (brown patches) represent water.

The Drought History charts (Figure 16) show the individual response of the drought indices for Bourke, Ivanhoe, Wentworth, and Broken Hill. The indicators are high at all locations. 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 17) shows that the North West, Northern Tablelands and North Coast Local Land Service regions are in the Non-Drought category.

The seasonal NDVI anomaly data (Figure 18) indicates normal levels of greenness across most of the regions for the November to January period. Parts of the North West LLS region has average to below average levels of greenness. Flood affected areas may be represented by lower levels of greenness. 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 19) show the individual response of the drought indices for Tenterfield, Moree, Walgett,and Lismore. The Plant Growth indicator has declined at Tenterfield and Lismore, likely due to below average rainfall received in January. 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 20) 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 January.

The seasonal NDVI anomaly data (Figure 21) shows near normal to high levels of plant greenness across most of the LLS regions for the November to January period. Parts of the Central West have average to well below average levels of greenness. Flood affected areas may be represented by lower levels of greenness. 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 22) show the individual response of the drought indices for Cowra, Condobolin and Singleton. The CDI indicators remain high at all locations and suggest a strong outlook to the start of autumn. 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 23) shows that the South East Local Land Services region is in the Non-Drought CDI category.

The seasonal NDVI anomaly data (Figure 24) shows near normal to high levels of plant greenness. However, greenness levels have decreased slightly across the region since the December Update. 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 25) show the individual response of the drought indices at Bega, Cooma and Goulburn. Despite the drop in soil water, plant growth and rainfall indices for Bega, and a smaller drop for Cooma and Goulburn, all indices remain relatively high and the three regions are in the Non-Drought category. 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.

Official national outlook

The official national outlook was released by The Bureau of Meteorology on 9 February 2023. The rainfall outlook for March to May shows that parts of the south and east of Australia, including southern Western Australia, central and southeast Queensland, and northern and central Victoria, have a 60% to 70% chance of below median rainfall. Northern parts of the Northern Territory and Kimberly have a 60% chance of above median rainfall. Forecast accuracy at this time of year has generally been moderate to high.

Maximum temperatures are likely to be cooler than average for the New South Wales central coast. Maximum temperatures are likely to very likely to be above median for subtropical Australia and the far north of Cape Yor Peninsula. Above median minimum temperatures are very likely for most of Australia for the 3-month period between March to May. Parts of central Australia and the Great Australian Bight are expected to 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

Central and western NSW have a 35% to 55% chance of exceeding above median rainfall between March and May. The east coast and ranges, and parts of southeast NSW have a near equal chance to more than 65% chance of receiving above median rainfall over the 3-month period (Figure 26). There is a 60% to 70% chance of below median rainfall on the western slopes of the Great Dividing Range.

The maximum temperature outlook indicates a more than 60% chance of exceeding median daytime temperatures for most of NSW. The chance of warmer than median daytime temperatures increases in parts of the north and southeast; there is up to a 75% chance of above median maximum temperatures in parts of northern NSW, the North Coast and South East LLS regions (Figure 27). There is a below average chance of exceeding median temperatures in the Hunter region.

There is a 65% to above 80% chance of warmer than median overnight temperatures in eastern NSW during the March to May period (Figure 28). West of the Great Dividing Range, there is a near equal to above 65% chance of above median overnight temperatures.

Global climate drivers

El Niño–Southern Oscillation (ENSO)

The Bureau of Meteorology’s El Niño-Southern Oscillation (ENSO) Outlook was released on 31 January 2023. The ENSO Outlook status is currently at La Niña. La Niña typically increases the chance of above average rainfall in eastern Australia in summer. Climate models suggest SSTs will return to neutral ENSO conditions during February, persisting until mid-autumn.

Southern Oscillation Index

The 30-day Southern Oscillation Index (SOI; Figure 29) for the 30 days ending 29 January was +12.9. The 90-day SOI value was +12.9. 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)

Sea surface temperatures (SST) were cooler than average along the equator in the central and eastern tropical Pacific Ocean. Warm anomalies continue in the Coral Sea to the north-east of Australia and are particularly strong around Tasmania and New Zealand (Figure 30).

The latest values of the three NINO indices in the tropical Pacific for the week ending 29 January were: NINO3 -0.4 °C, NINO3.4 -0.6 °C, NINO4 -0.5 °C.

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 26 January 2023) shows cool anomalies to 150m depth in the eastern equatorial Pacific Ocean (Figure 31). Warm anomalies of more than 3^oC above average, persist west of 160^oW from 50m to 250m depth.

Indian Ocean (IOD)

The Indian Ocean Dipole (IOD) is currently neutral. All of the five international climate models surveyed by the Bureau of Meteorology indicate that a neutral IOD will continue through February and into autumn. Whilst the monsoon trough is in the southern hemisphere from December to April, the IOD has little influence on Australia’s climate. The latest weekly value of the Indian Ocean Dipole (IOD) index to 29 January 2023 was -0.06 °C.

Southern Ocean (Southern Annular Mode – SAM)

The Southern Annular Mode (SAM) index is positive (as of 04 February) and is expected to return to neutral during February (Figure 32). In summer a positive SAM increases the chance of above average rainfall in eastern NSW.

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 1-3 week timescales.

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 (2022), Panorama Avenue, Bathurst 2795 and data which is © Commonwealth of Australia 2022, 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.