NSW Seasonal Conditions Summary March 2016

Highlights

  • Rainfall was below average across most of NSW during February, with warmer than normal daytime temperatures.
  • The rainfall outlook for March to May is for a near equal chance of drier or wetter than normal conditions. Wetter than normal conditions are possible in the south west and areas of the north. Warmer temperatures are likely for most of NSW.
  • During March, there is a near equal chance of drier or wetter than normal conditions across most of NSW, with drier conditions likely in the far south west and south east. Warmer than normal temperatures are likely.
  • The El Niño event has declined to a moderate level, with sea surface temperatures continuing to decrease. It is likely to continue into late autumn. Neutral conditions are likely to follow. A La Niña event is possible, but less likely.
  • Topsoil moisture levels declined as a result of the warm, dry and often windy conditions.
  • Pasture growth was declined, with summer-growing pastures haying off. Supplementary feeding commenced in some areas due to lack of pasture biomass and feed quality.
  • Despite declining soil moisture, interest in dual purpose winter crops remains high.
  • Livestock condition is generally good.
  • Harvesting of early sown sorghum has been completed and later sown crops are approaching maturity. Yield prospects of late sown sorghum crops have declined, but generally remain average to slightly above average. Yield prospects in some northern areas may be higher. Prospects for irrigated crops remain good.

Overview

Rainfall during February was below average across 74 per cent of the state, with the remainder of the state receiving near-average rainfall. Much of the rainfall across inland NSW occurred during the first week of the month. Daytime temperatures were above average, particularly in the west and north and conditions were windy, contributing to high evaporation.

The hot, dry conditions caused pasture growth to decline sharply across most of NSW during February. Particular declines occurred across the far west, western Riverina, central west, north west, northern tablelands, central tablelands and the central areas of the north coast. Growth declined, but was maintained at reasonable levels along areas of the coast, south east, south west slopes, southern tablelands and the east of the central tablelands.

Relative to historical records, February pasture growth was below average across areas of the far north west, north west, central west, central and northern tablelands, upper Hunter valley and north coast, but was near average across most of the remainder of NSW.

Biomass levels declined across most of NSW. The greatest declines occurred across most of western and central NSW, the north west, western Riverina and areas of the far south.

Stock condition remains good in many areas as a result of the good growth of perennial summer growing pastures and lucerne during January. However, in many inland areas stubbles have mostly been grazed out, biomass is now limited, feed quality has declined and supplementary feeding is commencing.

The hot, dry weather in February caused topsoil moisture to decline rapidly. Despite this, interest in early sowings of dual purpose winter crops remains high due to their flexibility, grazing potential and performance last year. Sowings across the tablelands and upper slopes have been delayed by the dry conditions.

Harvesting has been completed for most early sown sorghum crops in the north, with some late sown crops approaching maturity. Maturity of these crops has been hastened by the dry, hot weather. Modelling by QAAFI at the end of February suggests that the yield prospects for sorghum (grown after a winter fallow) in northern NSW have remained above average despite the conditions, although the prospects in north-central NSW are closer to average. In the south, yields are likely to be average to slightly above average. The yield potential for dryland sorghum and cotton crops has decreased the most where soil moisture reserves were lower. Irrigated crops continue to have a good yield potential, although high evaporation rates have increased water requirements.

Modelled topsoil moisture declined across most of the state to low levels during February, with the exception of areas of the coast. By the end of the month, levels were below average across most of northern, north western and central NSW, as well as many southern areas.

Modelled subsoil moisture levels remained relatively stable during the month, but improved across areas of the coast and also showed a slight improvement across some areas of the far south and the north west. Levels remained moderate across most of the tablelands and slopes.

Stock water supplies are declining in many areas, with the added complication of algal blooms in dams and waterways. Areas of some concern are in the west of the central and southern tablelands, the northern tablelands, the northern slopes, the west and north east of the central west, the upper Hunter valley and areas of the far west, far south and north coast.

NSW Seasonal Conditions Report – March 2016

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Seasonal outlook

The Bureau of Meteorology’s rainfall outlook for March to May indicates there is a near-neutral outlook 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 the south west of NSW and areas of the northern central west and north west. Warmer than normal daytime temperatures are likely across most of NSW for the period. There a near-neutral outlook for daytime temperatures across areas of the far west. Overnight temperatures are likely to be warmer than normal across NSW.

During March, there is a near-neutral rainfall outlook for most of NSW. Drier than normal conditions are likely across the south east, areas of the southern tablelands and areas of the far south west. Warmer than normal daytime and overnight temperatures are likely across most of NSW.

The NOAA Climate Forecast System (CFS) rainfall outlook for March to May indicates wetter than normal conditions are likely for areas of southern and western NSW and there is a near-neutral outlook for the remainder of the state. For March, the NOAA CFS rainfall outlook is near-neutral for most of NSW, with wetter than normal conditions possible in areas of the far south and south west.

Of the global climate models surveyed during early March, 43 per cent of models indicated a wetter than normal outlook for the March to May period, 7 per cent drier than normal and 50 per cent near-neutral.

The AussieGRASS pasture growth outlook has very poor accuracy at this time of year. Historically, skill levels for the outlook are low in late summer and autumn, and it should therefore be regarded with caution For March to May, it suggests below average to average growth in the west, north west and western Riverina, average growth for the central west, and above average growth for areas of the south and the central and southern tablelands. Below average growth is suggested for areas of the coast, Monaro, Hunter valley and northern tablelands. However, this may be an artefact of the growth model. The rainfall prediction that the growth outlook is based upon suggests wetter than normal conditions are likely across southern and central NSW, with a drier than normal outlook for the north east and a near-neutral outlook for the north, far south west and most of the coast. This was based on a consistently negative SOI during January and February. The rainfall outlook is reasonably consistent with that of the Bureau of Meteorology, with the exception of the north east..

El Niño Southern Oscillation (ENSO)

The Pacific Ocean remains in a moderate El Niño event, with sea surface temperatures in the NINO 3 and 3.4 regions and subsurface temperatures continuing to decline.

Most modelling suggests 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 early March (based on the Bureau of Meteorology’s thresholds), the majority suggested a return to neutral conditions by April-June, with some suggesting the possibility of a La Niña event in winter or spring. Historically, model accuracy is low in the autumn.

The effects of an El Niño event on rainfall tend to decrease in the year after the event. This is detailed in the Bureau of Meteorology’s analysis of the past 12 strongest El Niño events. However, these probabilities vary from region to region across the state and every El Niño event is different.

The equatorial Pacific sea temperatures and cloud conditions remain consistent with an El Niño event. The 30-day SOI is generally variable during the monsoon season and during this time is of limited use as an indicator. It is currently strongly negative. Trade winds were generally weaker than average till January, consistent with an El Niño event, but have been mostly near-normal since.

Warm sea surface temperature anomalies extend across the central and eastern equatorial Pacific. Sea surface temperatures are near-normal in the equatorial Pacific west of the International Date Line. Warm sub-surface temperature anomalies in the central to eastern equatorial Pacific have weakened substantially due to the passage of a cool anomaly at depth. The cool anomaly strengthened during the month now extends into the eastern equatorial Pacific at a depth of 50-150m. This with other indicators signals the decay of the El Niño event, and may be an indication of a developing La Niña event.

Warm sea surface temperatures exist to the north of the continent, as well as to the north east and north west, and in much of the Indian Ocean. Sea surface temperatures have cooled off the coast of Western Australia. These are generally positive indicators for rainfall across south eastern Australia, although cloud levels have been low across Indonesia and Papua New Guinea.

Climatic outlook summary

NSW Seasonal Outlook

Current outlook

Previous outlook

Quarterly Rainfall

Near neutral
(most of NSW)

Wetter
(south west and areas of the south, north west and northern central west)

Wetter
(most of NSW)

Near neutral
(areas of the central and southern tablelands, Monaro, south coast, Sydney basin, Hunter valley and far north coast)

Quarterly Maximum Temperature

Warmer
(most of NSW)

Near neutral
(far western NSW)

Cooler
(most of NSW)

Near neutral
(most of the coast, far south east, Sydney basin and lower Hunter valley)

Quarterly Minimum Temperature

Warmer

Near neutral
(most of NSW)

Cooler
(areas of the central tablelands, Upper Hunter valley, central west and north west)

Warmer
(areas of the far south east)

El Niño Southern Oscillation (ENSO)

ENSO (overall)

El Niño

El Niño

BoM ENSO Tracker Status

El Niño

El Niño

SOI

Variable, currently strongly negative

Variable, currently moderately negative

Pacific Ocean (NINO3.4)

Warm
(above El Niño thresholds) but declining

Very warm
(above El Niño thresholds) but declining

Indian Ocean (IOD)

IOD neutral (variable)

Warm sea surface temperatures

IOD neutral (variable)

Southern Annular Mode (SAM/AAO)

Weakly - moderately positive

Weakly – moderately positive

Rainfall and temperature

During February, rainfall across the state ranged from 0-292 mm. Rainfall distribution across most of the western and central areas of the state was variable. Falls of generally less than 5-10 mm occurred in areas of the west, north west, Riverina, central west and central tablelands. Over the remainder of the north west, Riverina, central west and central tablelands, and across the northern tablelands falls of generally 10-25 mm were received. Some areas (particularly in the east) received 25-50 mm and areas in the eastern Riverina and the east of the northern tablelands received 50-100 mm. The south east, south and central coast generally received 10-50 mm, with some areas of the Illawarra receiving 50-100 mm. The best falls occurred across the mid-north to north coast, with most areas receiving 50-100 mm and some areas up to 200 mm. However, some areas near Grafton received less than 25 mm.

Daytime temperatures were above average for the month across most of NSW, with a heatwave late in the month. Overnight temperatures were slightly elevated over most of NSW, but were above average in the north west.

Relative rainfall

Relative to historical records, rainfall during February was below average across 74 per cent of NSW. Across this area, most of the rainfall was in the lowest 10 per cent of recordings. This included areas of the north coast, northern tablelands, northern slopes, Sydney basin, central west and central tablelands. The remainder of NSW received near-average rainfall for the period.

Quarterly relative rainfall was average across 72 per cent of NSW but below average for 18 per cent. Well above average to extremely high relative rainfall occurred across areas of the mid-north coast, Hunter valley, Sydney basin and far south coast. Areas of below average relative rainfall occurred across areas of the far north west, the central west, western Riverina, southern tablelands and the north coast near Grafton.

Soil moisture

Average modelled topsoil moisture declined across most of NSW during February, with the exception of areas of the coast. Relative to historical records, topsoil moisture during February was average across most of NSW and above average in the south and some areas of the north west. It was below average across most of the north coast, northern tablelands and in the west near Bourke. By the end of the month, levels had declined and were below average across most of northern, north western and central NSW, as well as in many southern areas.

Modelled subsoil moisture levels remained relatively stable during the month, but improved across areas of the coast, and improved slightly across some areas of the far south and the north west. Levels remained moderate across most of the tablelands and slopes. Relative to historical records, subsoil moisture was average across most of the state, but remained below average across areas of the north west, northern central west, far south and areas of the central and northern tablelands. Above average relative subsoil moisture occurred across areas of the far west, central NSW, the Hunter valley, mid-north coast and far south east.

Streamflow

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

The Bureau of Meteorology's streamflow forecast indicates a mix of low to near-median streamflows are likely across most NSW monitoring stations during March to May.

Relative pasture growth and biomass

Relative to historical records, AussieGRASS modelled pasture growth declined during February to generally average to below average levels across much of NSW. Below average growth occurred in areas of the far north west, north west, the western edge of the central west, northern tablelands, upper Hunter valley and the central areas of the north coast. Growth was generally average across the south of the state. Limited areas of above average relative growth occurred across some of the south east, eastern Riverina and far south. There were large areas of missing data in the far west.

Other pasture growth models suggested generally average growth for the south, southern Riverina, south east, Sydney basin, lower Hunter valley, mid-north coast and areas of the north west. However, well below average to extremely low relative growth occurred across western NSW, most of the central west, central and southern tablelands, northern Riverina, northern slopes, northern tablelands and areas of the north coast.

Over the quarter, AussieGRASS relative growth was average across 58 per cent of the state but below average over 27 per cent, including areas of the far north west, far west, northern central west and western Riverina. Above average growth was generally restricted to isolated areas of the tablelands, upper Hunter valley and the south east.

During February, relative biomass levels declined, but generally remained average across NSW. Most of the decline was due to areas of above average biomass along the coast and tablelands declining to near-average. There was an increase in areas of below average relative biomass in the far west and areas of the far south.

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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 9 March 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 (9 March 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.