NSW Seasonal Conditions Summary February 2017

Overview

Rainfall across NSW during January was near average across 65 per cent of the state and below average across 21 per cent. Below average rainfall occurred across areas of coastal, central and south eastern NSW. In some areas, the January rainfall occurred due to thunderstorms and was relatively ineffective.

Pasture growth slowed across most of NSW during January due to above average temperatures and high evaporation. Growth remained moderate across areas of the eastern Riverina, far south, north coast, the east of the northern tablelands and areas of the far north west. Growth declined or remained low across most of the remainder of NSW, particularly the south east, Sydney basin and upper Hunter valley.

Relative to historical records, growth was below average across much of north western, central and south eastern NSW and the west of the northern tablelands. It was average or slightly better across areas of the far west, south, Riverina and the north coast.

Other pasture growth models indicated generally below to well below average growth across much of NSW.

Pasture biomass declined across most of NSW, particularly across areas of the south coast, tablelands, north west, central west and Hunter valley. Relative to historical records, biomass remained well above average across much of inland NSW, but average to below average across the tablelands, slopes, Monaro, Hunter valley and the coast. Relative biomass was particularly low over the south coast and the Sydney basin.

Stock condition remained generally good during January, although high temperatures and declining feed quality and availability in some areas have resulted in some stock losing condition. Supplementary feeding has recommenced in some areas.

High temperatures during January accelerated summer crop growth and increased crop water requirements. In the north, dryland crops have been stressed and yields are likely to suffer, particularly for dryland sorghum and cotton. Crop development in the south remains slightly delayed by late sowing and the cooler conditions in early December. The yield potential for irrigated crops in southern NSW is average to above average, particularly for rice and cotton.

Topsoil moisture remained relatively low across much of inland NSW, with declines across the south east and the central and southern areas of the state. The rainfall received over areas of the north east provided a slight improvement in topsoil moisture.

Subsoil moisture levels declined in most areas, particularly across the central and southern areas of the state and the south east.

Run off during January was below average across areas of coastal, central, south eastern and north western NSW, but above average across some areas of the far west and the northern tablelands.

NSW Seasonal Conditions Report – February 2017

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Seasonal outlook

The Bureau of Meteorology’s rainfall outlook for February to April (see table) indicates drier than normal conditions are likely across most of NSW, with a near-equal chance of drier or wetter than normal conditions across areas of the south to mid-north coast. Temperatures are likely to be warmer than normal across most of NSW, with the possibility of a near-equal chance of cooler or warmer than normal overnight temperatures in areas of the far south and south west.

During February, drier than normal conditions are likely across the north of NSW, the central west, upper Hunter valley and areas of the central tablelands and Riverina. There is a near-equal chance of drier or wetter than normal conditions for the south, areas of the far west, the south east, the Sydney basin and the lower Hunter valley. Daytime temperatures are likely to be warmer than normal across most of the state with a near-equal chance of cooler or warmer than normal conditions in the south west. Warmer than normal overnight temperatures are likely across most of the eastern half of NSW.

The NOAA Climate Forecast System (CFS) rainfall outlook for February to April is near-neutral for most of NSW. Below-average rainfall is possible across some areas of the tablelands and north east. The overall temperature outlook is for warmer than normal conditions across most of NSW, except for some areas of the south east.

For February, the CFS rainfall outlook is near-neutral for most of NSW. The temperature outlook suggest warmer than normal conditions are likely across the north, Hunter valley and the coastal strip.

A survey of the major climate models in early February indicated that most (77 per cent) favoured a generally near-neutral outlook (that is, a near-equal chance of drier or wetter than normal conditions) for February to April. One model favoured a generally wetter outlook and two a generally drier outlook. The Bureau’s seasonal outlook for the period was included in the latter. For temperature, most models (62 per cent) favoured a warmer than normal outlook, with four favouring a generally near-neutral outlook. It should be noted that the model accuracy tends to be lower through to late autumn.

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
February – April 1 10 2 8 4 1
March – May 1 6 4 7 2 2

The AussieGRASS pasture growth outlook for February to April suggests that below average pasture growth is possible across areas of the far west, western Riverina, north west, tablelands, upper Hunter valley and Sydney basin. However, in areas of the east, this is likely to be due to the model assuming limited soil nitrogen. Above average growth is suggested for areas of the coast and the south west slopes.

The seasonal rainfall prediction that the growth outlook is based upon is for near-equal chance of drier or wetter than normal conditions for most of NSW between February and April. This was based on a near zero SOI phase during December and January. In comparison, the Bureau of Meteorology’s February to April rainfall outlook suggests drier than normal conditions across most of NSW.

The current growth outlook has a very low past accuracy across most of NSW, and accuracy is likely to remain low into autumn and early winter.

El Niño Southern Oscillation (ENSO)

The Pacific Ocean remains in an ENSO-neutral state. Most models suggest neutral conditions continuing throughout summer and autumn, with gradual warming of sea surface temperatures in the central equatorial Pacific. Some models suggest warming to weak El Niño levels by winter due to the current temperatures, the rate of warming and the activity of the Madden-Julian Oscillation. However, model skill tends to be low until late autumn.

Sea surface temperatures during January were near-average to slightly below average in the central and eastern-central equatorial Pacific. Temperatures were above average in the eastern equatorial Pacific, and the warmer temperatures have expanded to the west since early January. Temperatures were also above average in the western equatorial Pacific. Temperatures in the Indian Ocean were near-average to slightly below average, and near average to the north of Australia. Recently, temperatures have warmed along the east coast of Australia.

During January, cloud remained high over areas of Australia, Papua-New Guinea, Indonesia and the Philippines. Cloud levels were relatively normal across much of eastern Australia. Cloud levels remained low near the junction of the equator and the International Date Line and to its east and west.

The cool subsurface temperature anomaly extending across the central and eastern equatorial Pacific continued to weaken during January but strengthened slightly in early February. Weak warm anomalies were present in areas of the west.

The easterly Pacific trade winds were near average over the month. After increasing to borderline positive levels in early January, the SOI returned to neutral levels.

The Bureau of Meteorology’s ENSO outlook status is inactive. The CPC/IRI also indicate ENSO neutral conditions are present and have a neutral outlook for summer to early autumn. Note that the Bureau and CPC/IRI use different thresholds.

The sub-tropical ridge is in a near-normal position. The Southern Annular Mode (SAM) was negative throughout most of late spring and summer, increasing the likelihood of drier conditions during the period. The SAM is now near-neutral, and likely to remain close to this level into mid-late February. A shift in the SAM to weakly positive is possible in late February and early March.

Climatic outlook summary

NSW Seasonal Outlook (BoM)

Current outlook

Previous outlook

Quarterly Rainfall

Drier

(most of NSW)

Near neutral

(areas of the south to mid-north coast)

Drier

(most of NSW)

Near neutral

(areas of western and south western NSW)

Quarterly Maximum Temperature

Warmer

Warmer

(most of NSW)

Near neutral

(areas of far western NSW)

Quarterly Minimum Temperature

Warmer

(most of NSW)

Near neutral

(areas of southern and south western NSW)

Warmer

(most of NSW)

Near neutral

(areas of western and south western NSW)

El Niño Southern Oscillation (ENSO)

ENSO (overall)

Neutral

Neutral

BoM ENSO Outlook Status

Neutral

Neutral

SOI

Neutral

Neutral

Pacific Ocean (NINO3.4)

Neutral

(near neutral and warming)

Neutral

(slightly cool but warming)

Indian Ocean (IOD)

Neutral

Neutral

(slightly warm but cooling)

Southern Annular Mode (SAM/AAO)

Near-neutral

(tending to remain near-neutral to weakly positive)

Weakly to moderately negative (trending to weakly negative-neutral)

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

Rainfall and temperature

Rainfall was less than 60% of average across much of NSW during January, particularly in areas of the south east.

Rainfall across the state ranged from 1-404 mm, with most of NSW receiving between 10-50 mm for the month.

Higher falls occurred across areas of the north east, including areas of the northern slopes, northern tablelands and north coast. Some of these falls occurred due to thunderstorm activity.

Rainfall across much of the Riverina, the south and areas of the south east and far west was less than 25 mm.

It was the third-warmest January on record across NSW. Daytime and overnight temperatures were well above average across most of NSW, particularly in the east and north.

Relative rainfall

Rainfall across NSW during January was near average across 65 per cent of the state and below average across 21 per cent.

Areas of the coast, central west, central tablelands, Sydney basin and the south east received below average rainfall, as did areas of the north west, Hunter valley, mid-north coast and eastern Riverina.

Above average rainfall occurred across areas of the far west, north west, northern tablelands and the north coast.

Quarterly relative rainfall was average across 55 per cent of the state, above average across 18 per cent and below average across 27 per cent. Above average rainfall occurred across areas of the far west, plus limited areas of the Riverina. Below average rainfall occurred across most of the coast and areas of the north west, central west, tablelands and the Hunter valley.

Soil moisture

Topsoil moisture remained relatively stable across much of inland NSW during January. Declines occurred across the south east and central and southern NSW. The rainfall received over areas of the north east provided a slight improvement in topsoil moisture. Topsoil moisture remained at levels of less than 20 per cent of a saturated profile across much of NSW, and generally less than 30 per cent across the north east.

Relative to historical records, January topsoil moisture levels were near average across most of NSW. Levels were above average over areas of the far west and some areas of the far south and north east. Below average topsoil moisture occurred across areas of the central tablelands, central west, north west, Sydney basin, Hunter valley, mid-north to lower north coast and the central to south coast.

Subsoil moisture levels declined in most areas, particularly across the south east, central and southern areas of the state. Relative to historical records, levels remained extremely high across much of inland NSW. Levels were average across areas of the north west, the eastern areas of the tablelands, south east slopes, lower Hunter valley and areas of the far north coast and south coast. Subsoil moisture was below average from the Illawarra through to the lower north coast.

Streamflow

Run off was below average across areas of coastal, central, south eastern and north western NSW, but above average across some areas of the far west and the northern tablelands.

Yearly run off to January remained influenced by the wet winter of 2016. Yearly run off was above average to extremely high across much of NSW, with the exception of areas of the north west, Liverpool Plains, the Hunter valley, Sydney basin and the mid-north to north coast.

The Bureau of Meteorology's streamflow forecast indicates near-median streamflows are likely across most NSW monitoring stations during February to April. Low flows are likely at some north eastern and south eastern locations.

Relative pasture growth and biomass

Relative to historical records, AussieGRASS modelled pasture growth during January was below average across much of the north west, central west, central and southern tablelands, upper Hunter valley, Sydney basin, Monaro, south coast and the west of the northern tablelands. Growth was near-average across one third of NSW including most of western and southern NSW, the lower Hunter valley and the east of the northern tablelands. Above average growth occurred across areas of the far west, far south, central Riverina and the far north coast.

Other pasture growth models indicated below average growth across much of NSW, with well below average to extremely low growth across areas of the north west and the far south east. Growth was near-average across areas of the far south, northern slopes, northern tablelands and far north coast.

Over the quarter, AussieGRASS relative growth was below average across 41 per cent of NSW, extending across much of northern, eastern, central and south western NSW. Much of the far west, south and Riverina had near-average growth. Areas in the north of the far west had above average growth.

During January, relative biomass levels remained above average across much of inland NSW. Relative biomass was near-average to below average across most of the tablelands, slopes, Monaro and the Hunter valley. Areas of the south coast and the Sydney basin had well below average to extremely low relative biomass.

Figure 1: Relative monthly topsoil moisture

Pasture growth 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 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 13 February 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 (13 February 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.