NSW Seasonal Conditions Summary January 2016

Highlights

  • Early December was dry across much of inland NSW, with rainfall across much of the state late in the month.
  • The rainfall outlook for January to March is near-neutral for much of NSW. Drier than normal conditions are likely in the south east and wetter than normal conditions in the far north east. Warmer daytime and overnight temperatures are likely for the eastern half of NSW.
  • During January, there is a near-neutral rainfall outlook for most of NSW. Drier than normal conditions are likely in the south east. Warmer than normal temperatures are likely across the eastern half of NSW, and cooler overnight temperatures in the west.
  • The El Niño event appears to have peaked, but is likely to continue into autumn. Historically, its effects on rainfall across NSW decline during summer.
  • Topsoil moisture declined during December, but improved in early January. There was a slight decline in subsoil moisture during December.
  • Pasture growth declined across most of NSW during December, although average to above average growth was maintained in the north east
  • Summer crop yield prospects were enhanced by the mid-late December and early January rainfall, particularly in the north

    Overview

    Early December was dry across much of inland NSW. Apart from the north east of the state, most rainfall occurred from mid-late month, with heavy rainfall across the central to mid-north coast and Hunter valley.

    Rainfall during December was average across 62 per cent of the state. Above average rainfall occurred across areas of western NSW, the Hunter valley, central coast and areas of the central and northern tablelands and mid-north coast. Below average rainfall occurred in areas of the far south west, north west, northern central west, southern tablelands and the south east. The remainder of the state received near-average rainfall. Heavy rainfall also occurred across areas of the central to mid-north coast, Hunter valley and south coast in early January.

    Pasture growth declined across most of inland NSW during December as a result of the generally dry conditions early to mid-month. Growth across the western half of NSW declined from moderate to low levels, and in the eastern half of NSW from high to low-moderate levels. Production has been maintained in lucerne stands and in perennial pastures in areas of the east.

    Relative to historical records, December pasture growth was below average to average across most of NSW. Above average growth occurred across areas of the central and northern tablelands, Hunter valley and mid-north to north coast.

    Biomass levels declined slightly across most of western and central NSW, but remained high in areas of the Riverina and central tablelands. Levels remained reasonably stable along most of the tablelands and coast, but slightly declined in the south east.

    Summer crop growth and yield prospects were enhanced by the mid-late December rainfall in areas of the north west, central and southern NSW, with areas of the north and north west receiving excellent follow up rainfall in early January. Modelling by QAAFI suggests that the yield prospects for sorghum (grown after a winter fallow) in northern NSW are close to average in many areas. Prospects are above average in the north east and the south of the Liverpool Plains but somewhat below average in the northern central west and the north of the Liverpool Plains. The early January rainfall will have improved prospects further.

    Modelled topsoil moisture declined across most of the state during December, particularly in the north west, west, southern and central areas. Levels were stable in the north east. The early January rainfall improved levels in the north west, northern tablelands, Hunter valley, much of the coast and areas of the Riverina.

    Modelled subsoil moisture levels declined slightly in most areas. Levels remained moderate to high across most of the coast and south east and moderate across most of the tablelands and slopes.

    Subscribe to the Seasonal Conditions e-newsletter

    The Seasonal Conditions e-newsletter will let you know as soon as the monthly report is published. Subscribe now.

    Seasonal outlook

    The Bureau of Meteorology’s rainfall outlook for January to March is near-neutral for most of NSW. This means there is a near-equal chance of drier or wetter than normal conditions. Wetter than normal conditions are likely across far north eastern NSW. Drier than normal conditions are likely for an area of the south east, extending across the southern tablelands, Monaro and south west slopes. There a near-neutral outlook for daytime temperatures across the far west, areas of the western Riverina and areas of southern NSW for the period. Warmer than normal daytime temperatures are likely across most of eastern NSW including areas of the north west, central west, south west slopes, tablelands and coast. Cooler than normal daytime temperatures are likely across areas of the far south west. Warmer than normal overnight temperatures are likely across most of the coast, tablelands, Hunter valley and north west. Cooler than normal overnight temperatures are likely across areas of the far west, south west and western Riverina.

    During January, there is a near-neutral rainfall outlook for most of NSW. Drier than normal conditions are likely in the south east, including the south coast, southern tablelands, Monaro and Sydney basin, as well as areas of the south west slopes, central tablelands and southern Hunter valley. Warmer than normal daytime temperatures are likely across the eastern half of NSW, including the coast, tablelands, Monaro, central west, north west and eastern-central Riverina. Warmer than normal overnight temperatures are likely in the east, including most of the coast, tablelands, north-eastern central west and the north west. Cooler than normal conditions are likely across areas of western and southern NSW.

    Of the global climate models surveyed during early January, 36 per cent of models indicate a wetter than normal outlook for the January to March period, 18 per cent drier than normal and 56 per cent near-neutral.

    The pasture growth outlook for January to March suggests generally average growth is likely across most of western NSW. Above average growth is suggested for areas of the tablelands (except the eastern half of the northern tablelands), central west, south east and Riverina. Generally below average growth is suggested for the Hunter valley and north coast. However, past accuracy for this outlook is low to very low across NSW, although moderate across areas of the tablelands and Riverina. Historically, skill levels for the pasture growth outlook are low into autumn, and the outlook should therefore be regarded with caution. The rainfall prediction that the growth outlook is based upon suggests a near-neutral outlook for much of NSW, with wetter than normal conditions likely for areas of southern and central NSW. This was based upon rapidly falling SOI during November to December. The rainfall outlook is reasonably consistent with that of the Bureau of Meteorology, although the latter suggests drier than normal conditions in areas of the south west slopes and south east.

    El Niño Southern Oscillation (ENSO)

    The Pacific Ocean remains in a strong El Niño event, although sea surface and subsurface temperatures have declined.

    Most modelling continues to suggest that the El Niño event is likely to continue until late autumn or early winter 2016, followed by a return to neutral conditions. Of global climate models surveyed by CPC/IRI in mid-December (based on the Bureau of Meteorology’s thresholds), the majority suggested a return to neutral conditions, with a small number suggesting a La Niña event and one model suggesting a continuation of the El Niño event. Historically, model accuracy declines into autumn.

    The effects of an El Niño event on rainfall tend to decrease during summer. During the past 12 strongest El Niño events, the Bureau of Meteorology’s analysis shows that rainfall across the state (as a whole) was lower than normal in about 25-33 per cent of cases and near average or above in about 66-75 per cent of cases. However, these probabilities vary from region to region across the state and every El Niño event is different.

    The equatorial Pacific sea temperatures, trade wind and cloud conditions remain consistent with an El Niño event. The SOI has been variable and is currently weakly to moderately negative. It tends to be variable during the monsoon season.

    Warm sea surface temperature anomalies extend across the central and eastern equatorial Pacific, but have weakened during December. Sea surface temperatures are near-normal in the equatorial Pacific west of the International Date Line and have cooled near eastern Indonesia. Sub-surface warm temperature anomalies remain across most of the central to eastern equatorial Pacific, but have weakened and reduced in depth. The cool anomaly in the west continues to move eastwards at depth into the central equatorial Pacific. This with other indicators tends to signal the decay of the El Niño event. The recent movement of the Madden-Julian Oscillation into the western Pacific may however temporarily slow the decline of the El Niño event.

    Climatic outlook summary

    NSW Seasonal Outlook

    Current outlook

    Previous outlook

    Quarterly Rainfall

    Near neutral
    (most of NSW)

    Wetter
    (far north east)

    Drier
    (areas of the south east, Monaro, southern tablelands and south-west slopes)

    Near neutral
    (most of NSW)

    Wetter
    (north east, Northern Tablelands, areas of northern slopes and plains and areas of mid-north coast)

    Drier
    (limited areas of south east)

    Quarterly Maximum Temperature

    Warmer
    (north west, central west, eastern Riverina, tablelands, Monaro and coast)

    Near neutral
    (most of western NSW, western Riverina and far south)

    Cooler
    (far south west)

    Near neutral
    (most of NSW)

    Warmer
    (far north west, south east, central tablelands, areas of Hunter valley and mid-north coast)

    Cooler
    (far south west)

    Quarterly Minimum Temperature

    Warmer
    (north west, coast, Hunter valley, north western central west and tablelands)

    Near neutral
    (far north west, south western central west, eastern Riverina, and south west slopes)

    Cooler
    (far west)

    Near neutral
    (most of NSW)

    Warmer
    (far north west, coastal strip, areas of south east, central tablelands, Hunter valley)

    Cooler
    (areas of far south west)

    El Niño Southern Oscillation (ENSO)

    ENSO (overall)

    El Niño

    El Niño

    BoM ENSO Tracker Status

    El Niño

    El Niño

    SOI

    Variable, currently weakly-moderately negative

    Variable, currently moderately negative

    Pacific Ocean (NINO3.4)

    Very warm
    (above El Niño thresholds)

    Very warm
    (above El Niño thresholds)

    Indian Ocean (IOD)

    Neutral

    Neutral

    Southern Annular Mode (SAM/AAO)

    Weakly-moderately positive

    Neutral – moderately negative

    Rainfall and temperature

    During December, rainfall across the state ranged from 0.4-394 mm, with most of the state receiving 10-50 mm. Falls of less than 10 mm occurred across areas of the far north west, the far south west and the north western area of the central west. Falls of 25-50 mm occurred across some central areas of the far west, areas of the Riverina, far south and central west and the western half of the north west. The southern areas of the central west, Riverina and areas of the south east received 10-25 mm. Most of the northern slopes and central west received 50-100 mm, with the Sydney basin, Hunter valley, northern tablelands and north coast generally receiving 50-200 mm. Isolated areas of the mid-north coast received more than 200 mm.

    Most rainfall occurred late in the month. Significant storm rainfall occurred across the central to north coast mid-month, with the Sydney basin receiving widespread large hail and a tornado in the south east.

    Heavy rainfall occurred across areas of the central to mid-north coast, Hunter valley and south coast in the first week of January, resulting in areas of flooding.

    Temperatures were above average for the month, particularly in the south and west during the first half of the month.

    Relative rainfall

    Relative to historical records, rainfall during December was near-average across most of NSW. Rainfall was below average across areas of the far south west, southern tablelands, south east, north west and northern areas of the central west. Areas of above average relative rainfall occurred across the far west, northern tablelands, mid-north coast, Hunter valley and across the northern areas of the central tablelands and the Sydney basin.

    Quarterly relative rainfall was average across most of NSW, but was below average across areas of the far south west, south east and northern areas of the central west and north west. Above average rainfall occurred across areas of the mid-north and far north coast, Hunter valley, Sydney basin, central tablelands, central west and isolated areas of far western NSW and south eastern NSW.

    Soil moisture

    Average modelled topsoil moisture levels declined across most of inland and south eastern NSW during December due to the warm, dry conditions across most of these areas over early-mid month. Relative to historical records, topsoil moisture was average across most of NSW, but below average across the far south west, south east and areas of the north west and northern central west. It was above average in areas of the north east, including areas of the north coast, Hunter valley and the north of the northern tablelands. It was also above average in some areas of the far west to the north of Broken Hill.

    In early January, topsoil moisture levels across the state were average to above average as a result of the late December and early January rainfall.

    Modelled subsoil moisture levels declined slightly across in most areas but remained moderate to high across most of the coast and south east. Levels remained moderate across most of the tablelands and slopes. Relative to historical records, subsoil moisture was average across most of the state, but below average across areas of the north west, northern central west, far south and areas of the central and northern tablelands.

    Streamflow

    Yearly run off estimates to December showed some improvement, but remained variable in many areas. Run off was low across the north of the central tablelands, as well as western areas of the central west and areas of the north west and far south. Areas of low run off also occurred in the upper Hunter valley and central and northern areas of the northern tablelands. Run off was high over areas of far western NSW, the south east and areas of the central coast, lower Hunter valley and central Riverina.

    The Bureau of Meteorology's streamflow forecast indicates generally near-median streamflows are likely across most inland southern NSW monitoring stations during December to February. Some stations are tending towards low streamflows in the far south. In the south east, near-median to high streamflows are likely. Low flows are likely in the north east.

    Relative pasture growth and biomass

    Relative to historical records, AussieGRASS modelled pasture growth declined during December and was below average to average across most of NSW. Below average relative growth occurred across areas of the north west, far south west, the northern central west and the south east. Above average growth was restricted to areas of the Hunter valley, far north coast and areas of the northern and central tablelands. In the far west, areas of above average relative growth occurred in the far north west and the east.

    Other pasture growth models suggested a similar pattern, with below average relative growth across the north west, far north west, far south west and south east. Most of the Riverina, south, central west and far west had average growth, as did areas of the central tablelands and Sydney basin. The Hunter valley, mid-north to north coast and much of the northern tablelands had above average relative growth.

    Over the quarter, AussieGRASS relative growth was generally average across the state. Below average growth occurred across areas of the far south west, north west, northern areas of the central west, eastern Riverina and southern tablelands. Above average growth occurred across the upper Hunter valley, northern areas of the central tablelands and much of the north coast.

    During December, relative biomass levels were generally average across NSW. Relative biomass levels were above average across the mid-north to north coast, northern tablelands, Hunter valley and the northern central tablelands. Levels were low in areas of the far south, far north west, southern tablelands and eastern Riverina.

    Figure 1: Relative monthly topsoil moisture

    Soil moisture map

    Figure 2: Relative quarterly pasture growth

    Pasture growth map

    More information

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

    Acknowledgements

    Information used in this report was sourced from the Australian Bureau of Meteorology, CSIRO, the Queensland Department of Science, Information Technology and Innovation, the Australian Export Grains Innovation Centre, the Queensland Alliance for Agriculture and Food Innovation, the U.S. Department of Agriculture, U.S. Department of Commerce, the U.S. National Oceanic and Atmospheric Administration, the International Research Institute for Climate and Society (Columbia University), the UK Meteorological Office, the APEC Climate Centre, NSW Local Land Services 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 8 January 2016.

    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 (8 January 2016). 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.