NSW Seasonal Conditions Summary June 2015

Highlights

  • Rainfall across NSW during May was average to above average in the north, but below average in the south west. Heavy rainfall occurred across areas of the mid-north to north coast.
  • Drier than normal conditions and warmer than normal daytime temperatures are likely across most of across most of eastern, central and northern NSW between June and August. Overnight temperatures are likely to be warmer over eastern, northern and areas of central and southern NSW.
  • During June, drier than normal conditions are likely across much of eastern, central, southern and northern NSW, with warmer daytime temperatures likely across much of northern, central and eastern NSW. Across much of the south and far south west, there is a near-equal chance of cooler or warmer than normal daytime temperatures. There is a near-equal chance of cooler or warmer than normal overnight temperatures across most of inland NSW.
  • An El Niño event has commenced, appears to be strengthening and may continue into spring. Reduced winter/spring rainfall, higher daytime temperatures and an increased risk of frost are likely.
  • Topsoil moisture levels improved along the central to north coast and improved slightly in the west. Subsoil moisture levels were generally stable, but improved across the coast. Continued poor run off has limited farm water supplies in many areas.
  • Pasture growth was maintained over most of NSW, but declined over the south west and areas of the western and central Riverina and remained low in the north west.
  • Sowings of early maturing winter crops continued during May, with an increase in the area sown to chickpeas. Early to mid-season winter crops have established well, particularly in the north east of the central west. Grazing of forage and early sown crops has commenced, particularly on the tablelands and slopes. Crop establishment and growth has been patchy in areas of the north west, south west and the southern central west. Follow up rainfall is urgently required in these areas. Cotton crops have generally yielded well.
  • Resources to assist in management for areas suffering poor rainfall and growth are available at Managing drought.

Overview

Rainfall during May was average or above across northern and areas of central NSW, but below average in areas of the far south west, the western and central Riverina and the far south east. Above average rainfall occurred across the mid-north to north coast, most of the Hunter valley and areas of the northern tablelands, far north west and northern central west.

Rainfall across some drought affected areas of the north west stimulated some pasture growth and sowing of winter crops on marginal moisture. However, rainfall in these areas was insufficient to replenish subsoil moisture.

Pasture growth improved or was maintained across central and areas of southern NSW. It declined across areas of the Riverina and the south west and west. Growth remained relatively stable across the coast, but remained low across areas of the north west. Flooding and waterlogging has restricted pasture growth in low lying areas of the mid-north to north coast and Hunter valley.

Relative to historical records growth in May was similar to April across most of NSW, however declines occurred across areas of the south west and western Riverina. These areas showed below average relative growth, as did areas of the north west. Relative growth remained near average along the coast and the east of the tablelands. Well above average relative growth occurred across areas of the northern slopes, northern and central tablelands and areas of the central west, south west slopes and far south. Supplementary feeding is continuing in areas of north western and western NSW.

Biomass levels remained similar to April, with some declines across the east. Biomass remained low across much of central and western NSW and along the coast. Relative to historical records, biomass was well below average across the north west (west of the Newell Highway) and below average in the western Riverina and the east of the far west. It was above average across much of the tablelands, slopes, north coast, far south and areas of the far west. Across the remainder of the coast, west and central NSW, relative biomass was near average.

Sowings of early maturing winter crops continued during May, with an increase in the area sown to chickpeas. Early to mid-season winter crops continued to establish and produce well, particularly in the north east of the central west. Grazing of forage and early sown crops has commenced, particularly on the tablelands and slopes.

However, topsoil moisture has declined and subsoil moisture is marginal over the north western and south western areas of the cropping belt, and across the south west of the central west. Crop establishment in some of these areas has been patchy and crops urgently require follow up rainfall.

Good cotton yields were obtained, particularly in the south. Harvesting of soybean crops on the north coast has been delayed due to the April/May rainfall, and quality may suffer.

Topsoil moisture levels improved slightly across western NSW, declined slightly across areas of the north west, the south east and central NSW, remained low in the western Riverina, and improved along the coast from the Illawarra to the north. Subsoil moisture levels remained relatively stable, remaining low in areas of the north and west but increasing along the coast.Streamflow analysis over the last twelve months indicated continued improvement in run off across much of the coast, but it remained low across much of central and north western NSW, the north and east of the far west, the Riverina and most of the tablelands. Some localities within these areas have received run off due to storm rainfall, but stock water levels are near critical in others.

NSW Seasonal Conditions Report – June 2015

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Seasonal outlook

Drier than normal conditions and warmer than normal daytime temperatures are likely across most of across most of eastern, central and northern NSW between June and August. There is a near-equal chance of drier or wetter than normal conditions in the far north east, the far west and areas of the south. There is a near equal chance of warmer or cooler than normal daytime temperatures across areas of the far west and far south west.

Warmer than normal overnight temperatures are likely over eastern, northern and areas of central and southern NSW between June and August. There is a near equal chance of warmer or cooler than normal overnight temperatures across areas of the central west, far west and far south west.

During June, drier than normal conditions are likely across much of eastern, central, southern and northern NSW. There is a near-equal chance of drier or wetter than normal conditions across much of the far west and far north east corner of NSW. Warmer daytime temperatures are likely across much of northern, central and eastern NSW during June. Across much of the south and far south west, there is a near-equal chance of cooler or warmer than normal daytime temperatures. There is a near-equal chance of cooler or warmer than normal overnight temperatures across most of inland NSW during June. Warmer than normal overnight temperatures are likely in the far north east, the central to mid-north coast and the far south east. Cooler than normal overnight temperatures are likely in the south west.

Updated outlook information suggests that wetter than normal conditions are likely for the remainder of June, with warmer than normal daytime temperatures in the south, central west and east. Overnight temperatures are likely to be warmer.

The pasture growth outlook for June to August is extremely variable. It suggests slightly above average growth is possible over the period for the central west, coast, tablelands and Hunter valley. Below average growth is possible for most of the north west and much of the southern and south eastern areas of the far west. Variable growth is possible across the Riverina, south, and far south east. Below average growth is possible over the far western and northern/central areas of the Riverina

Skill levels are moderate to high in most of these areas, but the outlook for areas of the Hunter valley, central west, far north west and south east low skill. The outlook is based a rapidly falling SOI in April/May, and a probability of below average rainfall across much of inland NSW and above average rainfall across coastal NSW during June to August.

El Niño Southern Oscillation (ENSO)

An El Niño event has commenced, and is likely to persist through winter and spring. The Bureau of Meteorology's ENSO tracker status is now at 'El Niño'.

The NOAA Climate Prediction Centre and International Research Institute for Climate and Society in the USA have indicated that (based on their thresholds and indicators) the El Niño event is currently weak to moderate, although there is some uncertainty about how strong it may become.

An El Niño event is generally associated with below-average rainfall across NSW (particularly inland NSW) during winter and spring, above average daytime temperatures, lower than average streamflow and an increased risk of frost. However, the strength of an El Niño event is not necessarily linked the degree of its effect on rainfall in eastern Australia.

Warm sea surface temperatures anomalies extend across the central and eastern equatorial Pacific, and strengthened in the east during May. All NINO indices (to 14 June) are more than 1°C above normal, with the NINO 2 index (far east) more than 2°C above normal.

The SOI remained in the neutral range between mid-April to early May, but until recently has been at negative levels. The SOI was -13.7 as at 31 May, but increased to 0.6 as at 14 June. This is due to local weather factors rather than climatic influences. Westerly anomalies in the trade winds extend across the western and central equatorial Pacific, and the trade winds have been consistent weaker than average throughout the year. Cloud at the junction of the equator and the International Date Line declined slightly in early June but has increased since. It has generally been above average since early March. These indicators are generally consistent with coupling between the atmosphere and ocean.

Climatic outlook summary

NSW Seasonal Outlook Current outlook Previous outlook
Quarterly Rainfall

Drier
(areas of northern, central, eastern NSW)

Neutral
(far west, far south west, far north east)

Wetter

Quarterly Maximum Temperature

Near neutral
(far west, far south west)

Warmer
(northern, eastern, central NSW)

Cooler
(western and areas of central NSW)

Near neutral
(southern, eastern, most of central NSW)

Warmer
(far south east)

Quarterly Minimum Temperature

Warmer
(northern, eastern, southern, south eastern NSW)

Near neutral
(central areas of far west, areas of central NSW)

Warmer

El Niño Southern Oscillation (ENSO)
ENSO (overall) El Niño El Niño
BoM ENSO Tracker Status El Niño El Niño
SOI Negative Negative
Pacific Ocean (NINO3.4)

Warm
(Above El Niño thresholds)

Warm
(Above El Niño threshold and warming)

Indian Ocean (IOD) Neutral Neutral
Southern Annular Mode (SAM/AAO) Weakly negative – near neutral Near neutral – weakly negative

Rainfall and temperature

During May, rainfall across the state ranged from 1-402 mm, with the heaviest falls over the mid-north to north coast and occurring as a result of an East Coast Low early in the month. In the south west, western Riverina and areas of the south east over the Monaro, rainfall was below average and ranged from 1-10 mm.

Average daytime temperatures were close to normal across NSW during May. The central areas, central tablelands, upper south west slopes, and central to mid-north coast had temperatures of up to 1.0°C below normal, as did areas of the far north west.Average overnight temperatures were 0.7°C above normal across NSW during May. Overnight temperatures were generally 1.0°C cooler than normal in the south, near normal across northern and central NSW and 1.0-2.0°C warmer across the Hunter valley and northern central west.

Relative rainfall

Relative to historical records, rainfall during May was above average to extremely high across 37 per cent of the state, average over 44 per cent and below average over 19 per cent..

Areas of the far south west, the western, central and northern Riverina and the far south east received below average relative rainfall. Areas of the Hunter valley and mid-north to north coast and the eastern fall of the northern tablelands received well above average rainfall. This was due to the effects of an east coast low early in the month. The northern areas of the far west and the northern areas of the central west also received above average rainfall. Rainfall across the remainder of the state was near average.

Quarterly relative rainfall was average or above over 97 per cent of the state, but was below average across areas of the north west and central/western Riverina. Above average rainfall for the period occurred primarily across the Sydney basin, Hunter valley, northern tablelands, areas of the north coast, northern slopes and northern central west.Half yearly relative rainfall was above average across most of eastern and areas of far western NSW. It was below average across areas of the north west, but average across most of central and western NSW.

Soil moisture

Modelled topsoil moisture levels improved slightly across western NSW but still remained low. Levels of topsoil moisture remained low in the far south west and western Riverina. Levels declined slightly across areas of central NSW and the south east and improved along the coast from the Illawarra to the north.

Relative to historical records, topsoil moisture was generally average or above across most of the state. Areas of the coast and adjacent tablelands from the Illawarra north generally had above average to well above average soil moisture. Areas of the central and western Riverina had below average topsoil moisture, as did areas between Ivanhoe and Balranald, south of Deniliquin and in the north east around Bourke.

Modelled subsoil moisture levels were generally stable during May, remaining low in areas of the north and west but increasing along the coast.Relative to historical records, subsoil moisture was below average across much of the north west and areas of the northern tablelands, Liverpool plains, central tablelands and Riverina.

Streamflow

Despite the autumn rainfall, many inland areas have experienced very little run off. Farm water supplies are low in many areas, with some areas critically low.Streamflow analysis over the last year indicated below average run off over much of northern and central NSW, the north and east of the far west, the tablelands, the upper Hunter valley and the Riverina. Run off was average or better over much of the coast, Monaro and areas of the far west.

The Bureau of Meteorology's streamflow forecast indicates near median streamflows are likely across south eastern Australia during June to August. High May streamflows were recorded at some coastal locations .

Relative pasture growth and biomass

Relative to historical records, AussieGRASS modelled pasture growth was similar to April, although it declined in areas of the south west and western Riverina. Across the coast and the eastern fall, relative growth remained near average. It remained well above average across areas of the northern slopes, the central tablelands, and areas of the central west, south west slopes and far south. Relative growth remained low in areas of the north west to the west of the Newell Highway.

Relative growth for May was below average over 12 per cent of NSW, average over 47 per cent and above average over 27 per cent.

Other pasture growth models indicated well above average growth for temperate pastures across most of northern, central and eastern NSW and the tablelands. Growth was average across the coastal strip of the north coast, southern NSW and in areas of the north west. Growth was below average in the far south west.

Over the three months to May, relative growth was average to above average across much of the tablelands, northern slopes and areas of the south and far west. It was below average across areas of the north west (west of the Newell Highway), the south east, the north western Riverina and the north east of western NSW. The remainder of central and coastal NSW had near average growth.

Relative biomass levels were similar to April, except for a decline in the western and northern Riverina and the east of Western NSW.  Across much of the north coast, Hunter, central and northern tablelands, northern slopes, central west, far south and eastern Riverina relative biomass was above average. Relative biomass remained low across the north west and much of the western Riverina. About 24 per cent of NSW had below average relative biomass levels, and 75 per cent average or better relative biomass levels.

Figure 1: Relative monthly topsoil moisture

Soil moisture map - June 2015

Figure 2: Relative quarterly pasture growth

Pasture growth map - June 2015

More information

For more information, contact the NSW Department of Primary Industries on 02 6391 3100 or Local Land Services on 1300 795 299.

Acknowledgments

Information used in this report was sourced from the Bureau of Meteorology, CSIRO, Queensland Department of Science, Information Technology and Innovation, NSW Local Land Services, the US National Oceanic and Atmospheric Administration, the International Research Institute for Climate and Society (Columbia University) and NSW Department of Primary Industries.

External links

Disclaimer

The seasonal outlooks presented in this report are obtained from the Australian Bureau of Meteorology and other sources. 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. Outlook information was up to date as at 12 June 2015.

Recognising that some of the information in this document is provided by third parties, the State of New South Wales, the author and the publisher take no responsibility for the accuracy, currency, reliability and correctness of any information included in the document provided by third parties.

The information contained in this publication is based on knowledge and understanding at the time of writing (12 June 2015). However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of the Department of Primary Industries, Local Land Services or the user's independent adviser.