NSW Seasonal Conditions Summary February 2016

Highlights

  • Rainfall was above average across most of NSW during January, but variable in some areas due to storms.
  • The rainfall outlook for February to March is for wetter than normal conditions across most of NSW, with a near-neutral outlook for areas of the coast. Cooler daytime temperatures are likely for most of NSW, but the outlook for overnight temperatures is near-neutral.
  • During February, there is a wetter than normal rainfall outlook for most of NSW. Cooler than normal daytime temperatures are likely across most of NSW, with cooler overnight temperatures in eastern, central and northern areas.
  • The El Niño event is declining, but is likely to continue into late autumn. Neutral conditions are likely to follow.
  • Topsoil moisture levels improved across eastern and north western NSW during January, and in some central areas.
  • Pasture growth was generally above average across most of the eastern half of NSW during January, with summer-growing pastures and lucerne responding to the rainfall and warm temperatures.
  • The improved soil moisture has increased interest in dual purpose winter crops. Summer-growing weeds have been problematic in paddocks to be sown to winter crops.
  • Yield prospects of late sown summer crops have been improved by the conditions, and are likely to be well above average if follow up rainfall occurs.

Overview

Rainfall during January was above average across nearly 70 per cent of the state, and near-average for most of the remainder. Much of the rainfall in inland areas was as a result of storms, with associated variability in falls. Heavy falls occurred in areas of the south, central and mid-north coast, Sydney basin and lower Hunter valley as a result of an East Coast Low and severe thunderstorms.

Pasture growth improved across the tablelands, south east and areas of the coast, west, central NSW and the north west as a result of the rainfall. Growth across some areas of the west and south west remained low. Perennial summer growing grasses and lucerne benefited particularly from the conditions, but haymaking proved difficult in some areas and the quality of standing dry feed was degraded.

Relative to historical records, January pasture growth was average to above average across most of NSW. Areas of particularly high growth occurred in the north west, tablelands, Monaro, Hunter valley and south east.

Biomass levels were similar to December and declined slightly across most of western and central NSW, the Riverina, far south, tablelands and coast. They remained relatively stable along the coast and tablelands.

The summer rainfall improved soil moisture reserves in many areas, boosting confidence for winter crops, but has stimulated prolific growth of weeds. Spraying of winter cropping paddocks has been necessary to ensure moisture and nitrogen levels are maintained. There has been particular interest in early sowings of dual purpose winter crops.

Harvesting has commenced for early sown sorghum crops in the north. In some areas, yields were affected by the dry conditions in early December. Modelling by QAAFI suggests that the yield prospects for sorghum (grown after a winter fallow) in northern NSW are average to above average. With follow up rainfall, particularly on later sown crops, yields are likely to be above to well above average. In the far south, average to above average summer crops yields are likely.

Modelled topsoil moisture improved across the eastern half of the state during January, particularly along the south to mid-north coast, Hunter valley, central tablelands and north west.

Modelled subsoil moisture levels remained relatively stable during the month, but increased in coastal areas. Levels remained moderate across most of the tablelands and slopes.

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Seasonal outlook

The Bureau of Meteorology’s rainfall outlook for February to April indicates wetter than normal conditions are likely across most of NSW. There is a near-neutral outlook for the Sydney basin, eastern areas of the central tablelands, and areas of the southern tablelands, south coast, central coast and far north coast. This means there is a near-equal chance of drier or wetter than normal conditions in these areas. Cooler than normal daytime temperatures are likely across most of NSW for the period. There a near-neutral outlook for daytime temperatures across coastal areas and areas of the far south east. There is a near-neutral outlook for overnight temperatures across most of NSW. This means there is a near-equal chance of cooler or warmer than normal conditions in these areas. Cooler than normal overnight temperatures are likely in areas of the north west, central west, central tablelands and upper Hunter valley. Warmer than normal overnight temperatures are likely in the far south eastern corner of NSW.

During February, wetter than normal conditions are likely across most of NSW. There is a near-neutral outlook for areas of the far west and areas of the far north east. Cooler than normal daytime temperatures are likely across most of NSW, with a near-neutral outlook for areas of the far west and far south east. Cooler than normal overnight temperatures are likely across most of eastern, central and northern NSW. There is a near-neutral outlook across areas of western, southern and south eastern NSW.

Of the global climate models surveyed during early February, 30 per cent of models indicate a wetter than normal outlook for the February to April period, 20 per cent drier than normal and 50 per cent near-neutral.

The pasture growth outlook has poor accuracy at this time of year. For February to April, it suggests generally above average growth is likely across most of NSW. Below average growth is suggested for areas of the coast, Monaro, Hunter valley and northern tablelands as well as far north western NSW. However, this may be an artefact of the growth model. The past accuracy of this outlook is low to very low across NSW, although moderate across areas of the south west. Historically, skill levels for the pasture growth outlook are low in late summer and autumn, and the outlook should therefore be regarded with caution. The rainfall prediction that the growth outlook is based upon suggests wetter than normal conditions are likely across most of NSW, with a near-neutral outlook for the north east, far north west and far south east. This was based upon rapidly falling SOI during December to January. The rainfall outlook is reasonably consistent with that of the Bureau of Meteorology.

El Niño Southern Oscillation (ENSO)

The Pacific Ocean remains in a strong El Niño event, although sea surface temperatures in the NINO 3 and 3.4 regions and subsurface temperatures have generally declined since late November.

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 mid-January (based on the Bureau of Meteorology’s thresholds), the majority suggested a return to neutral conditions by April-June, with a small number suggesting the possibility of a La Niña event. Historically, model accuracy declines in the autumn.

The effects of an El Niño event on rainfall tend to decrease during summer and into 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, trade wind and cloud conditions remain consistent with an El Niño event. The SOI has been variable and is currently moderately to strongly negative. It tends to be variable during the monsoon season.

Warm sea surface temperature anomalies extend across the central and eastern equatorial Pacific, and have continued to weaken, particularly in the east. Sea surface temperatures are near-normal in the equatorial Pacific west of the International Date Line but have warmed near Indonesia. They remain generally warmer than normal in the Indian Ocean. Warm sub-surface temperature anomalies remain across most of the central to eastern equatorial Pacific, but have generally weakened since November although some warming occurred during the last month. A cool anomaly remains at depth in the west and central equatorial Pacific, declined slightly in the central areas in January but has recently started to strengthen again. The movement of the Madden-Julian Oscillation into the western Pacific in late December and early January may have slowed the decline of the El Niño event.

Climatic outlook summary

NSW Seasonal Outlook Current outlook Previous outlook

Quarterly Rainfall

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

Near neutral
(most of NSW)
Wetter
(far north east)
Drier
(areas of the south east, Monaro, southern tablelands and south-west slopes)

Quarterly Maximum Temperature

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

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)

Quarterly Minimum Temperature

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)

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)

El Niño Southern Oscillation (ENSO)

ENSO (overall)

El Niño

El Niño

BoM ENSO Tracker Status

El Niño

El Niño

SOI

Variable, currently moderately negative

Variable, currently moderately negative

Pacific Ocean (NINO3.4)

Very warm
(above El Niño thresholds) but declining

Very warm
(above El Niño thresholds)

Indian Ocean (IOD)

Neutral (variable)

Neutral

Southern Annular Mode (SAM/AAO)

Weakly – moderately positive

Neutral – moderately negative

Rainfall and temperature

During January, rainfall across the state ranged from 7-586 mm, with most of the state receiving between 25-100 mm. Most of the rainfall resulted from storms, and was quite variable. Falls of less than 25 mm occurred in areas of the west and south west. Falls of 50-100 mm occurred across areas of the north west, assisting to replenish soil moisture reserves and encourage summer growing pastures in this area. Storms and an East Coast Low contributed to falls in excess of 200-300 mm across the central to mid-north coast, lower Hunter valley, Sydney basin and areas of the south coast. The heavy rainfall in these areas resulted in flooding.

Temperatures were generally above average for the month but were variable, with cool conditions during the rain events and heatwaves in mid-month.

Relative rainfall

Relative to historical records, rainfall during January was above average across nearly 70 per cent of NSW, and near average across most of the remainder. Rainfall was below average across limited areas of the north coast near Grafton and Kempsey, and a small area in the central tablelands near Blayney. The majority of the north coast, the southern areas of the northern tablelands and areas of the far west and far south received near-average rainfall. Areas of the south east, mid-north coast, Hunter valley, Sydney basin, central tablelands and the far south west received extremely high relative rainfall for the period.

Quarterly relative rainfall was above average across nearly 60 per cent of NSW and near-average for most of the remainder. Well above average to extremely high relative rainfall occurred across areas of the mid-north coast, Hunter valley, Sydney basin, far south coast and the north of the northern tablelands. Limited areas of below average relative rainfall occurred in the far south and the north coast near Grafton.

Soil moisture

Average modelled topsoil moisture levels improved across most of the eastern half of NSW during January, particularly along the south to mid-north coast, Hunter valley, central tablelands and north west. Levels also improved in areas of the central west. Relative to historical records, topsoil moisture was average to above average across most of NSW, but below average in the west near Bourke and on some areas of the north coast. It was well above average to extremely high across the Sydney basin, Hunter valley and the far south east. It was also above average across areas of central, north western and southern NSW.

In early February, topsoil moisture levels across the state were above average across much of north western, southern, south eastern and central NSW and average across the remainder.

Modelled subsoil moisture levels remained relatively stable during the month, but increased in coastal areas. 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, the Hunter valley, mid-north coast and far south east.

Streamflow

Yearly run off estimates continued to improve, but remained variable in many areas. Run off in the year to January remained low across the north of the central tablelands, as well as some southern/south 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 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 generally low streamflows are likely across most inland NSW monitoring stations during February to April. Some inland stations in the far south and north eastern Victoria are likely to have near median streamflows. In coastal locations and the tablelands, generally near-median flows are expected, although high flows are likely for the south and central coast.

Relative pasture growth and biomass

Relative to historical records, AussieGRASS modelled pasture growth generally improved during January and was average to above average across most of NSW. Limited areas of below average relative growth occurred across some of the north coast and of the far south. Above average growth occurred across much of the south east, Monaro, central tablelands, upper Hunter valley and the north west.

Other pasture growth models suggested better growth, with above average relative growth across the most of the north west, central west, south, southern and central tablelands, south east, Sydney basin and Hunter valley. The north of the northern tablelands and the far south west also had above average relative growth. Growth was generally average for the far west and for the north coast, with an area of below average growth near Grafton and near Wilcannia in the far west.

Over the quarter, AussieGRASS relative growth was average across 55 per cent of the state and above average over 32 per cent, including areas of the tablelands, upper Hunter valley, far west, eastern Riverina and the coast. Below average growth was generally restricted to isolated areas of the mid-north coast, far west, far south and the north of the central west.

During January, relative biomass levels were generally average across NSW. They were above average across areas of the northern and central tablelands, Sydney basin, upper Hunter valley and Monaro. Areas of above average biomass also occurred along the mid-north to north coast. Levels were low in areas of the far south, far north west and eastern Riverina.

Figure 1: Relative monthly topsoil moisture

Soil moisture map up to January 2016

Figure 2: Relative quarterly pasture growth

Pasture growth map up to January 2016

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 February 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 February 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.