NSW Seasonal Conditions Summary June 2017

Overview

During May, rainfall was slightly below average to near-average across 71 per cent of NSW, generally ranking at less than 60-80 per cent of normal. Rainfall was below average across areas of central, far western and north western NSW, as well as areas of the Illawarra, tablelands, Hunter valley and north coast. Areas of the central Riverina and far south also received below average rainfall.

Pasture growth was variable across the state, and slowed due to cooler overnight temperatures. Growth improved across the south of the state and areas of central and south western NSW, but declined across much of far western and eastern NSW. Growth remained limited across some areas of north western NSW, but improved across the eastern edge of western NSW.

Relative to historical records, pasture growth was slightly below average to near-average across much of NSW. It was above average across much of the south and areas of the central tablelands, south east and the south of the central west. Growth was below average across areas of the north west, central west, northern tablelands and much of the far west.

Other pasture growth models indicated below average growth across areas of central NSW, the north west, the far north coast and the far west, but above average growth across areas of the south west, northern tablelands, northern slopes and south coast. Growth across the remainder of NSW was generally near-average.

Pasture biomass was relatively unchanged during May, and generally remained quite low across most of NSW with the exception of areas of the central west and far south. Relative to historical records, biomass was generally average to above average across inland NSW and areas of the south east, but was below average across areas of the tablelands, northern slopes, upper Hunter valley and the Sydney basin.

Pasture establishment and winter growth across much of inland NSW will be highly dependent on urgently needed follow up rainfall and mild conditions.

Stock condition was generally average to very good during the month, although supplementary feeding has recommenced in many areas.

Winter crop planting continued into late May in districts where sufficient rainfall was received. In many areas, rainfall and soil moisture were insufficient for sowing, particularly over areas of the north west plains, central west as well as areas of the eastern and central Riverina. In these areas, rainfall during June will be needed to complete sowing. Establishing crops are patchy and struggling in many areas due to poor topsoil moisture levels. In other areas, there has been insufficient rainfall and soil moisture for germination and emergence. Dry conditions have been problematic for post-emergent herbicide application and have limited opportunities to apply nitrogen fertilisers. High levels of insect and mite pests have been reported in a number of areas. Follow up rainfall is urgently needed in most areas to ensure the successful germination, establishment and growth of winter crops.

Crops sown in April and early May responded to the late May rainfall, ensuring even establishment and early growth. Early sown grazing crops have continued to perform well, providing useful feed as cold, frosty conditions slowed pasture growth on the upper slopes and tablelands. Lack of soil moisture may limit recovery of some grazing crops, particularly canola.

Topsoil moisture improved across areas of southern NSW, but declined across areas of the north west, Hunter valley, tablelands, Sydney basin and the coast. Subsoil moisture levels were relatively stable across most of NSW, but declined slightly across coastal areas. Declines in soil moisture levels continued into early June.

Run off during May was above average across some areas of western, central, southern and south eastern NSW but below average across most of the coast.

NSW Seasonal Conditions Report – June 2017

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Seasonal outlook

The Bureau of Meteorology’s rainfall outlook for June to August (see the Climatic Outlook Summary below) indicates drier than normal conditions are likely across most of NSW. There is a near-equal chance of drier or wetter than normal conditions across areas of eastern NSW including the far south east, coast, lower Hunter valley and northern tablelands. Daytime temperatures are likely to be warmer than normal. Overnight temperatures are likely to be warmer than normal across areas of eastern, northern, central and southern NSW. There is a near-equal chance of cooler or warmer than normal overnight temperatures across most of western NSW and the western areas of the central west and Riverina.

During June, drier than normal conditions are likely for most of western and southern NSW, the Riverina, the southern tablelands and the southern half of the central west and central tablelands. For the rest of NSW, there is a near-equal chance of drier or wetter than normal conditions. Daytime temperatures are likely to be warmer than normal across most of NSW, with a near-equal chance of cooler or warmer than normal conditions in areas of the north, north west and far north west. There is a near-equal chance of cooler or warmer than normal overnight temperatures across most of NSW. Overnight temperatures are likely to be cooler than normal across areas of the far west, with warmer than normal conditions likely for the north east.

These outlooks have been influenced by warmer than normal sea surface temperatures in the tropical Pacific and cooler than normal temperatures in the eastern Indian Ocean. Higher than average pressure across southern Australia, has led to fewer cold fronts and low pressure systems.

The NOAA Climate Forecast System (CFS) rainfall outlook for June to August is drier than normal across most of NSW. For the coast and some tablelands and northern areas, the outlook is near-neutral (that is, a near equal chance of drier or wetter than normal conditions) for NSW. The overall temperature outlook is near-neutral for most of NSW. Warmer than normal conditions are possible for areas of the far north east and some areas of the coast, with cooler than normal temperatures possible for areas of the south west.

For June, the CFS rainfall outlook is for drier than normal conditions across most of NSW, with a near-neutral outlook for areas of the coast, northern tablelands and far north west. The overall temperature outlook is near-neutral for most of NSW, warmer than normal for the far north east and cooler than normal for areas of the south west.

A survey of the major global climate models in early June indicated that for the majority of NSW most models (54 per cent) favoured a drier than normal outlook for June to August period. The remainder of models favoured a generally near-neutral outlook (a near-equal chance of drier or wetter than normal conditions). For temperature, models were split between a warmer than normal and near-neutral outlook, with a slight majority favouring warmer than normal conditions.

The major multi-model ensembles surveyed favoured a drier than normal outlook for June to August and they were equally split between warmer than normal and near-neutral conditions.

Overall NSW outlook -

major climate models

Rainfall Outlook

(number of models)

Temperature Outlook

(number of models)

Period

Generally wetter

Generally

near-neutral

Generally

drier

Generally warmer

Generally

near-neutral

Generally

cooler

June – August

0

4

7

6

5

0

July – September

1

2

5

6

2

0

The AussieGRASS pasture growth outlook for June to August suggests that above average pasture growth is possible for areas of the north west, northern tablelands, central west, Riverina and far south. Above average growth is also possible for the Monaro, areas of the central tablelands and areas of the far west.

Below average growth is suggested for areas of the far north west and the central and southern tablelands, with average growth suggested across the remainder of NSW.

The SOI phase seasonal rainfall outlook that the growth outlook is based upon is for near-neutral to wetter than normal conditions for most of inland NSW between June to August. The outlook suggests drier conditions are possible along much of the coastal strip. This was based on a rapidly rising SOI phase during April and May. In comparison, the Bureau of Meteorology’s June to August rainfall outlook suggests drier than normal conditions across NSW. If these eventuate, potential growth may be very different from the outlook.

The current growth outlook has a moderate to high past accuracy across most of NSW.

El Niño Southern Oscillation (ENSO)

The Pacific Ocean remains in an ENSO-neutral state, with the outlook from most global climate models suggesting neutral conditions continuing through winter and into spring. The ENSO indicators remain near-neutral. Model skill is now improving.

The Bureau of Meteorology’s ENSO outlook status has moved to 'inactive' from ‘El Niño watch’. The CPC/IRI also currently indicate that ENSO neutral conditions are present and are likely to continue into winter and spring, but with a slightly elevated chance of El Niño development into spring. Note that the Bureau and CPC/IRI use different ENSO thresholds.

Some models indicate that a positive Indian Ocean Dipole (IOD) event remains possible, with slightly cooler sea surface temperatures in the eastern Indian Ocean and some warming in the west. However, any development appears to have temporarily stalled and the IOD remains neutral. Positive IOD events tend to suppress rainfall across Australia during winter and spring and can exacerbate the effects of an El Niño event.

Warming of sea-surface temperatures in the central equatorial Pacific occurred into late April, but stalled in May and early June. Whilst warm, temperatures in this region still remain within the neutral (neither El Niño nor La Niña) range. Sea surface temperatures in the far western Pacific remain warm, but have cooled to near-neutral levels in the east.

In the sub-surface areas of weak warm anomalies are persisting in the west at 150-300m, with a weak cool anomaly near the surface in the eastern equatorial Pacific. Weak warm anomalies are present in the east to depth. Without a reversal of the trade winds, the temperature anomalies in the west are unlikely to strengthen and move east in an El Niño-like pattern.

The easterly trade winds were close to normal throughout May in the central equatorial Pacific, with some strengthening in the western Pacific and reversal in the east.

The Southern Oscillation Index (SOI) has returned to neutral.

The Southern Annular Mode (SAM) is currently near-neutral. The outlook suggests it will increase to be moderately positive by late June to early July. Under ENSO-neutral conditions, other climate influences such as the SAM, atmospheric pressure and sea surface temperatures near the continent tend to have more influence.

Climatic outlook summary

NSW Seasonal Outlook (BoM)

Current outlook

Previous outlook

Quarterly Rainfall

Drier

(most of NSW)

Near-neutral

(areas of the coast, far south east, north east and the northern tablelands)

Drier

Quarterly Maximum Temperature

Warmer

Warmer

Quarterly Minimum Temperature

Warmer

(areas of eastern, northern, central and southern NSW)

Near-neutral

(most of western NSW, western Riverina and areas of the central west)

Near neutral

(most of NSW)

Warmer

(areas of eastern, south eastern and far north western NSW)

El Niño Southern Oscillation (ENSO)

ENSO (overall)

Neutral

Neutral

BoM ENSO Outlook Status

Inactive

El Niño watch

Southern Oscillation Index (SOI)

Neutral

Falling, currently below El Niño threshold

Pacific Ocean (NINO3.4)

Neutral

(warm)

Neutral

(slowly warming)

Indian Ocean (IOD)

Neutral

(eastern Indian Ocean slightly cool)

Neutral

(western Indian Ocean slowly warming)

Southern Annular Mode (SAM/AAO)

Near neutral

(trending to moderately positive)

Strongly positive

(trending to moderately positive then to near-neutral)

Note: Climate model outlooks are updated regularly. To check whether updates are available, use the hyperlinks provided.

Rainfall and temperature

During May, rainfall was slightly below average to near-average across most of NSW. Areas of the Illawarra to central coast, north coast, central tablelands, central west, north west, Riverina and much of the far west had rainfall of less than 40 per cent of average.

Rainfall across the state ranged from 1-207 mm, with most of the state receiving 10-50 mm and some areas 50-100 mm. Most of the north east, north west, southern and northern tablelands, south and south east received rainfall of 25-50 mm, with some areas receiving up to 100 mm. Isolated areas of the south and north coast and alpine areas received more than 100 mm.

Areas of the central Riverina, the north of the central tablelands, Hunter valley, central to mid-north coast, Sydney basin, southern highlands, north west and central west received 10-25 mm for the month. Some areas of the far west and north west received rainfall of 1-10 mm, as well as an area near Dubbo.

Over the state as a whole, rainfall was 41 per cent below average.

Daytime temperatures were generally average to above average for the month, particularly across areas of the north, north west and areas of central NSW.

Overnight temperatures were near-average across areas of the north west, north east and Illawarra to north coast, but below average across much of western, southern, south eastern and central NSW.

Relative rainfall

Rainfall across NSW during May was near-average across 71 per cent of the state and below average across 20 per cent of the state. Rainfall was above average across 9 per cent of the state.

Below average rainfall was received across areas of the far west, north west, central west, central Riverina, central tablelands, southern highlands, Sydney basin, Hunter valley, north coast and the Illawarra to central coast. Some of these areas received rainfall low enough to be in the lowest 10-20 per cent of years. Above average rainfall was limited to areas of the south west, Monaro, far south east, western Riverina, northern slopes and plains and the south of the central west.

Quarterly relative rainfall was average across 58 per cent of the state and above average across 36 per cent, with below average rainfall restricted to 6 per cent of the state. Below average rainfall occurred across areas of the far west and small areas of the north west and central Riverina. Rainfall was above average across much of eastern NSW, the northern tablelands, northern slopes and areas of the central west and south west.

Soil moisture

Topsoil moisture improved across areas of southern NSW, but declined across areas of the north west, coast, Hunter valley, Sydney basin and the tablelands.

Relative to historical records, May topsoil moisture levels were near average across much of NSW. Levels were above average across areas of the north west, northern tablelands, southern central west and the south west. Levels were below average across areas of the far west, central west, southern highlands, Sydney basin, lower Hunter valley and far north coast. Levels were also below average across the coast from the Illawarra to mid-north coast.

Subsoil moisture levels were relatively stable across most of NSW, but declined slightly across areas of the coast.

Relative to historical records, subsoil moisture levels remained extremely high across much of inland NSW. Levels were near average across areas of the north west, the eastern areas of the tablelands, the south west slopes and most of the coast and south east.

Streamflow

Run off during May was above average across areas of the south west, north west, south east and areas of the central west and northern slopes. It was below average across areas of the coast, Hunter valley, southern highlands and central tablelands.

Yearly run off to May remained above average to extremely high across much of NSW and average for areas of the far south west, north west and lower Hunter valley. Areas of the north west and Liverpool Plains had below average run off for the period.

The Bureau of Meteorology's streamflow forecast indicates near-median streamflows are likely at most NSW monitoring stations during June to August. Low to near-median streamflows are almost equally likely at some far southern locations.

Relative pasture growth and biomass

Relative to historical records, AussieGRASS modelled pasture growth during May was slightly below average to near-average across much of NSW. It was above average across areas of the south, south east, Monaro, central tablelands, the east of the Riverina and the south of the central west. Growth was below average across some areas of the north west, central west, northern tablelands and much of the far west.

Other pasture growth models indicated above average growth across areas of the south west, the western Riverina, the northern tablelands, south coast, northern slopes and the north of the lower Hunter valley. Growth was below average across much of the central and southern tablelands. Areas of the central Riverina, far north coast and the far west also had below average growth. Growth across the remainder of NSW was generally near-average.

Over the quarter, AussieGRASS relative growth remained below average across large areas of the far west, as well as areas of the north west, the east of the central west, the west of the northern tablelands and the upper Hunter valley. Areas of the central Riverina also had below average to near-average growth. Growth was above average across areas of the south, south east, Monaro, the south of the central west and along areas of the coast.

During May, relative biomass levels were above average across areas of central, southern and western NSW and the south east. Levels were generally average across areas of the west, central west and the Riverina but were below average across areas of the Sydney basin, upper Hunter valley, tablelands, north west and northern slopes.


Figure 1: Relative monthly topsoil moisture

Small map of relative soil moisture (upper level) - average value for May 2017

Figure 2: Relative quarterly pasture growth

Small map of pasture growth relative to historical records from 1957 - March 2017 to May 2017

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 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 June 2017 and was edited on 20 June 2017.

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 (9-20 June 2017). 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.