Weekly Rainfall Update

For the week to 9 October, rainfall was recorded across southern Western Australia; South Australia away from the far northwest and northeast; western and eastern Victoria; most of Tasmania, most of New South Wales; and southeast Queensland.

During the first few days of the week, an upper level trough and associated surface trough extended from northwest and central Queensland into western New South Wales. A low pressure system developed in northern central New South Wales and moved slowly towards the northeast coast and brought isolated thunderstorms and widespread rain over almost all of New South Wales and into southeast Queensland. Moderate falls were recorded in the Lower Western and Central West Slopes districts, as well as in smaller areas along the east coast of New South Wales and through southeast Queensland. Light to moderate falls continued over coastal regions as the low lingered near the coast well into the middle of the week.

In the west, a low pressure system near the southwest coast, and associated broad surface trough, moved slowly eastward over Western Australia during the first half of the week. The systems produced thunderstorms and moderate rain over the Goldfields and Southeast Coast districts, and lighter falls across the southwest and Nullarbor regions of Western Australia.

At the end of the week, troughs extending around the northern coasts of Australia and from the Kimberley through Central Australia to far southeast South Australia, were associated with extensive cloud and embedded thunderstorms. Mostly light falls were observed along a band extending from the west of the Northern Territory to western Victoria, though isolated locations received moderate totals. In the last day of the week a cold front crossing Tasmania and areas of low pressure over the mainland southeast also contributed.

Meanwhile the eastern end of the trough and the low pressure system lingering off the New South Wales Coast, saw continued falls from southeast Queensland to central coast New South Wales.

Rainfall totals exceeding 50 mm were recorded along the coast of New South Wales from Port Macquarie to the Illawarra. Totals in excess of 100 mm were observed at several locations, including the highest weekly total of 297 mm at Careys Peak in the Upper Hunter region of New South Wales. Isolated rainfall totals in excess of 50 mm were also recorded at some locations in the Capricornia, east Darling Downs and Southeast Coast districts of Queensland.

Rainfall totals between 10 mm and 50 mm were recorded in much of the southern South West Land Division, Southeast Coastal and southern Goldfields districts in Western Australia; patches of inland southern, central northern and far southeast regions of South Australia; pockets in western and far eastern Victoria; western Tasmania; southwest, central and eastern New South Wales; and southeast Queensland. An area of Western Australia from the southern Goldfields to the coast around Esperance observed totals in excess of 25 mm for the week, as did areas in a band through inland eastern to western New South Wales, though as the falls were associated with storms and showers coverage was patchy.

Little to no rainfall was observed over northern Western Australia; almost all of the Northern Territory; northwest and northeast South Australia; the central third of Victoria; parts of eastern Tasmania; and most of Queensland away from the southeast.

Impact of recent rainfall on deficits

The Drought Statement, issued on the 3 October 2018, discussed rainfall deficits over Australia for the 6-month (April–September 2018), the 9-month (January–September 2018) and 18-month (April 2017–September 2018) periods. Rainfall deficit maps are available for these periods as well as for standard periods.

The maps below show the percentage of mean rainfall that has been received for the rainfall deficit period for the 6-month, 9-month and 18-month periods ending 9 October 2018.

Rainfall for the period 1 April 2018 to 9 October 2018

Serious or severe rainfall deficiencies for the 6-month period persist across much of the eastern mainland, affecting northern and eastern Victoria, nearly all of New South Wales, large parts of southern, western, and eastern Queensland, and much of eastern South Australia away from the far southeast.

Large areas of serious or severe rainfall deficiencies are also in place for Central Australia and areas of Western Australia's interior, south coast, and the south of the Goldfields District.

Rainfall during the last week has somewhat reduced the severity of deficiencies across southern Western Australia, and has also reduced deficiencies to a lesser extent across much southeast Queensland and New South Wales.

Affected areas of northern and eastern Victoria and agricultural South Australia have generally received between 70% and 40% of average rainfall for the period. While the coastal south of Western Australia has now received between 80% and 60% of their average, the percentage of mean rainfall received decreased further inland. Most of New South Wales, inland eastern South Australia, and southern and eastern Queensland have received less than 50% of average rainfall for the period, though large areas of these States have received less than 40% of their mean, and totals still drop to less than 20% of mean for a large area spanning northwestern New South Wales, Queensland away from the southeast quadrant, and Central Australia.

Rainfall for the period 1 January 2018 to 9 October 2018

Serious to severe rainfall deficiencies for the 9-month period are evident across nearly all of New South Wales, except the northern coast, much of northern, southern central, and eastern Victoria, large parts of southern Queensland, and much of eastern South Australia except the far southeast. Since last month, an area of rainfall deficiencies have also developed on the south coast of Western Australia, between Albany and Hopetoun. 

Rainfall in the last week has slightly reduced the extent of serious deficiencies for this period through much of New South Wales, eastern South Australia, and southeastern Queensland. In Victoria away from western regions which received rainfall this week, deficiencies have generally increased slightly.

Affected parts of Victoria, eastern New South Wales, and agricultural districts of South Australia have generally received between 70% and 40% of average rainfall for the period. Percentage of average rainfall received drops further inland, with much a large area of northwestern New South Wales, southwestern Queensland, and northeastern South Australian having received less than 30% average rainfall for the period. The affected area on the south coast of Western Australia has received between 80% and 60% of the average.

Rainfall for the period 1 April 2017 to 9 October 2018

For the 18-months starting April 2017, rainfall deficiencies are still present over most of New South Wales away from the northeast coast and southern border; across eastern to central southern Victoria; southern, central, and southwestern Queensland, much of eastern South Australia except the far southeast, and along parts of the western and southern coast of Western Australia.

Recent during the past week has slightly reduced deficiencies at this timescale in the south of Western Australia, across southwestern and central New South Wales, and some parts of southeast Queensland.

Rainfall in affected areas of Western Australia, Victoria, agricultural districts of South Australia, southern New South Wales, and southeastern Queensland has generally been between 80% and 60% of average for the period. Percentages of mean rainfall have generally decreased further inland, with large areas of New South Wales away from the south and northeast, northeastern South Australia, and southwestern Queensland having received between 60% and 30% of average rainfall for the period.

Map of rainfall totals for this week

Product code: IDCKGRWAR0