NSW Seasonal Conditions Summary March 2015

Highlights

  • Rainfall during February was average across 67 per cent of NSW, but below average across nearly 30 per cent. The north west, central west and Hunter valley had low relative rainfall. Rainfall was above average over the north coast.
  • There is a near-equal chance of drier or wetter than normal conditions across most of NSW between March and May. Warmer than normal daytime temperatures are likely over southern and western NSW. Overnight temperatures are likely to be warmer.
  • During March, there is a near-equal chance of drier or wetter than normal conditions across most of NSW, with a slightly increased chance of wetter than normal conditions in the north west. Daytime and overnight temperatures are likely to be cooler in the north east, and overnight temperatures warmer in the south and west.
  • ENSO is neutral, although warming is occurring in the western and central equatorial Pacific. NINO3.4 temperatures may exceed the El Niño threshold in winter. NOAA indicates that a weak El Niño has commenced. Model skill is however low at this time of year.
  • Topsoil moisture levels declined over western and central NSW, were stable over most of the east and increased across the north coast. Subsoil moisture levels were generally stable, with improvements in the north east.
  • Pasture growth slowed or declined during February, particularly across central and north western NSW. Supplementary feeding of stock is occurring in some areas.
  • Early sown summer field crops are approaching maturity. Irrigated crops have maintained good yield potential. The dry February has reduced yield potential of dryland sorghum in the west of northern NSW.
  • Resources to assist in management for areas suffering poor rainfall and growth are available at Managing drought.

Overview

Rainfall during February was average across 67 per cent of NSW, and below average across 29 per cent. Rainfall was above average over much of the north coast and also in areas of southern-south eastern NSW.

Areas of the north west, central west and Hunter valley received below average rainfall for February, with an area between Moree, Lightning Ridge, Coonamble and Dubbo being extremely low. Over most of the State, rainfall was less than 40-60 per cent of normal.

Over the last year, below average rainfall occurred over areas of the north west between Walgett, Goodooga, Collarenebri and Brewarrina. Rainfall was also below average over areas of the northern tablelands near Armidale and scattered areas of the northern slopes, Liverpool Plains and Hunter valley. Areas around Hay and to the south east of Balranald were also affected.

During February, pasture growth declined across most of western, central and north western NSW, as well as areas of the south to mid-north coast. Growth slowed across the tablelands and the south west slopes. Relative to historical records, growth declined across most of NSW but generally remained near average except across north western and central NSW.
Biomass levels declined across most of NSW, particularly across central NSW and areas of the west. Relative to historical records, biomass was well below average in these areas but average in the west, and above average in the east, south east and areas of the far west.

Supplementary feeding of stock is occurring in some areas.

Early sown summer field crops are approaching maturity. Yield prospects for dryland sorghum crops have declined in some areas due to lack of February rainfall, particularly for late sown crops and areas west of the Newell Highway. Yield modelling by the QAAFI suggests potential sorghum yields in the west of northern NSW are 10-30 per cent below average, but in the east are average to slightly above average (0-20 per cent above average).

Irrigated cotton crops have maintained good yield potential. Drier conditions have increased water requirements on irrigated crops. Periods of cooler temperatures during January have had less effect on rice yields than initially expected. Heavy rainfall from ex-tropical cyclone Marcia has had a limited effect on sugar cane crops along the north coast.

Topsoil moisture levels declined during the month, particularly across western and central NSW. Subsoil moisture reserves are still limited in many areas.

Summer rainfall has not been sufficient to replenish stock water supplies in many areas.

Yearly streamflow analysis continues to indicate below average run off over areas of the north west, central and northern tablelands, northern slopes, Liverpool Plains, central west, Riverina, Hunter valley, and the Sydney basin. Run off improved across most of the north coast.

NSW Seasonal Conditions Report – March 2015

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Seasonal outlook

There is a near-equal chance of drier or wetter than normal conditions between March and May across the majority NSW. Wetter than normal conditions are likely in the far west between Broken Hill and Fowlers Gap.

Warmer than normal daytime temperatures are likely across most of southern and western NSW during the period. There is a near equal chance of warmer or cooler than normal daytime temperatures across areas of north west, northern tablelands and north coast.

Warmer overnight temperatures are likely over most of NSW, particularly in the south and west. There is a near-equal chance of warmer or cooler than normal overnight temperatures in far north eastern NSW.

During March, there is a near-equal chance of drier or wetter than normal conditions across most of NSW, with a slightly increased chance of wetter than normal conditions in the north west. Cooler daytime temperatures are likely across much of northern and north eastern NSW. For the rest of the State, there is a near-equal chance of cooler or warmer than normal daytime temperatures, except in the far south east where warmer daytime temperatures are likely. Overnight temperatures are likely to be warmer in the south and west, and cooler in the north east and areas of the north west.

During April, drier than normal conditions are likely across southern and eastern NSW, with a near-equal chance of drier or wetter than normal conditions elsewhere. Warmer than normal daytime and overnight temperatures are likely across most of NSW, except over the far north east.

The pasture growth outlook for NSW suggests below average growth across the north west, Liverpool Plains and the northern central west over the March to May period. Skill levels are moderate (although variable) in these areas. The skill levels of this outlook are low across most of NSW.

El Niño Southern Oscillation (ENSO)

ENSO is currently neutral, although warming is occurring in the western and central equatorial Pacific. The Bureau of Meteorology's ENSO tracker status is has shifted to 'El Niño Watch' from 'Neutral'. Climate models surveyed by the Bureau suggest central Pacific (NINO3.4 region) sea surface temperatures warming to above the Bureau's El Niño thresholds in winter.

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) a weak El Niño event commenced in February, and has a 50-60% chance of continuing through winter.

Model accuracy is low (the 'autumn predictability gap') and El Niño events normally decay rather than develop at this time of year. Historically, El Niño events have a limited effect on rainfall over much of NSW between March to May.
Sea surface temperatures have warmed in the western and the central equatorial Pacific, but remain near-average to cool in the east.

Sub-surface warm temperature anomalies have increased in the western-central Pacific and have moved eastwards. A cool anomaly remains in the eastern Pacific, but has decreased in intensity and size.

The SOI rose in mid-February and has been relatively stable over the last few weeks at near-neutral levels. Fluctuations in the SOI are common at this time of year.

Trade winds have shown signs of reversal in the western and central tropical Pacific, while remaining near normal in the east..

Climatic outlook summary

NSW Seasonal Outlook Current outlook Previous outlook
Quarterly Rainfall

Near neutral – neutral

Wetter
(areas of far western NSW)

Drier
(north west and areas of the central west and central tablelands and far south west)

Near neutral
(south, coast and north east)

Quarterly Maximum Temperature

Warmer

Near neutral
(north west and north east)

Warmer

Near neutral
(areas of the far north east, far south and far south east)

Quarterly Minimum Temperature

Warmer

Near neutral
(north east)

Warmer
(most of northern and coastal NSW)

Near neutral – neutral
(southern and far western NSW)

El Niño Southern Oscillation (ENSO)
ENSO (overall) Neutral – possible El Niño developing in winter (NOAA - weak El Niño) Neutral
BoM ENSO Tracker Status Neutral El Niño Alert
SOI Neutral  Neutral (currently negative)
Pacific Ocean (NINO3.4) Warm
(currently neutral, but warming)

Neutral – slightly warm

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

Rainfall and temperature

During February, rainfall across the State ranged from 0-600 mm, with most of the State receiving 10-50 mm. Rainfall was variable and below average across areas of the north, north west, northern central west, Hunter valley and far south western NSW. Areas of the north west and far west received 0-10 mm, 20 per cent or less of their normal rainfall. Rainfall over the north coast was high due to the passage of ex-tropical cyclone Marcia.

Daytime temperatures were 1.75°C warmer than normal across NSW during February. Overnight temperatures were 1.23°C above normal across NSW.

Relative rainfall

Relative to historical records, rainfall during February was average across most of the west and south of the State (67 per cent of NSW). Rainfall was above average over much of the north coast due to the effects of ex-tropical cyclone Marcia, and also in limited areas of southern-south eastern NSW.

Relative rainfall was below average across 29 per cent of NSW, including areas of the north west, central west and the Hunter valley. An area between Moree, Lightning Ridge, Moree, Coonamble and Dubbo was extremely low. Areas of the far south west also received below average relative rainfall for February.

Quarterly relative rainfall was above average over 56 per cent of the State, including most of the coast, tablelands, upper Hunter valley, south west slopes and the far west. Relative rainfall was average across much of central NSW and areas of the north west, but was below average across area between Walgett, Brewarrina and Goodooga.

Half yearly relative rainfall was average across the west, south and east of NSW. It was above average over the far north west, far south east and areas of the north coast. Below average relative rainfall occurred in areas of the north west, the Liverpool Plains, areas of the central west and an area of the far south west near Balranald.

Soil moisture

Modelled topsoil moisture levels declined across western and central NSW during February. Levels remained relatively stable across most of the coast, and improved over the north coast.

Relative to historical records, topsoil moisture was generally average across most of NSW, but high across the north coast and south/south east. Levels were below average across the north west between Narrabri and Bourke.

Modelled subsoil moisture levels were generally stable, but improved across areas of the north coast.

Relative to historical records, subsoil moisture remained below average across much of the north west and areas of the northern tablelands, Liverpool plains, central tablelands and areas of the Riverina. Subsoil moisture was extremely low across areas of the north west. Subsoil moisture was above average across areas of the far west, north coast and far south east.

Streamflow

Streamflow analysis over the last year indicated below average run off over areas of the north west, central and northern tablelands, northern slopes, central west, Riverina, Hunter valley, the Sydney basin and areas of the north coast. Storm rainfall has resulted in run off in some of these areas, but not in others and farm water supplies are variable. The Bureau of Meteorology's streamflow forecast indicates low streamflows are likely at most locations during March to May.

Relative pasture growth and biomass

Relative to historical records, AussieGRASS modelled pasture growth declined across most of NSW, particularly across most of central and north western NSW. Across the coast, central and southern tablelands and areas of the far west, relative growth declined from above average in January to near average in February. In the north west and central areas, relative growth declined to well below average. Relative pasture growth remained high across areas of the northern tablelands and far south.

Relative growth was below average over 28 per cent of NSW, average over 39 per cent and above average over just 9 per cent. However, there were large areas of missing data, particularly in the west.

Other pasture growth models indicated below average growth for temperate pastures across most of northern/north western NSW, the northern half of the central west, the far south west and areas of the Hunter valley. Above average growth was limited to the north coast, the eastern areas of the northern tablelands, and areas of the far south/south east. Over north western NSW, areas on the eastern and north eastern edges showed above average growth. For tropical pasture species, the best growth occurred across the north coast.

Over the three months to February, relative growth showed the influence of the December and January rainfall. Relative growth was above average across most of the east and far west of NSW, but below average across areas of the north west, Liverpool plains, the north of the central west and the western Riverina. Most of central NSW had average growth.

Relative biomass levels remained high across the tablelands, coast and across areas of the far west, but low across the north west and much of central NSW and the Riverina. About 27 per cent of NSW had below average relative biomass levels, and 72 per cent average or above average relative biomass levels.

Figure 1: Relative monthly topsoil moisture

Soil moisture map

Figure 2: Relative quarterly pasture growth

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.

Acknowledgments

Information used in this report was sourced from the Bureau of Meteorology, CSIRO, Queensland Department of Science, Information Technology, Innovation and the Arts, 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 8 March 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 (8 March 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.