Weekly Rainfall Update

For the week to 26 May 2020, rainfall was recorded in every State and Territory away from the central interior of the continent.

At the start of the week, a high pressure system in the Tasman Sea extended a ridge along Queensland's east coast, providing moist onshore flow onto the north tropical Queensland coast. Moderate to locally heavy falls exceeding 250 mm around Mission Beach were reported. Bingil Bay recorded 301.8 mm on the 21st, a new daily rainfall record for May at that site.

A surface trough extended from the Gulf Country, down through inland Queensland to the southeast of New South Wales and, along with another surface trough close to the east coast, produced isolated thunderstorms with widespread light to moderate falls across central, southern, and southeastern Queensland and eastern New South Wales.

During the first half of the week, a broad cloudband over northern Australia, and produced light to moderate falls across much of the Kimberley, central districts of the Northern Territory and the base of the Top End, and the Cape York Peninsula in Queensland. A broad upper trough maintained areas of rain across central to northern parts of Queensland, with widespread moderate falls across the northern half of that State during the middle of the week before the trough dissipated.

Also at the start of the week, a complex frontal system moved across southeastern Australia, with moderate falls recorded over much of Victoria, southeastern South Australia, and Tasmania. The passage of this front was associated with severe storms in parts of Victoria. By the middle of the week, this system had developed a complex low off the central and southern New South Wales coast, with further light to moderate rainfall in eastern New South Wales and northeastern Victoria. Snowfall was recorded in the Alpine regions.

Towards the end of the week, a deep low pressure system developed off the southwest coast of Western Australia as ex -tropical cyclone Mangga interacted with a strong cold front. A pre-frontal trough moved through the west Pilbara and Gascoyne, while the cold front moved through the west coast, and an associated complex low tracked the southwest and south coast. Squally and damaging winds, and moderate to locally heavy rainfall, were reported over parts of Western Australia from the west Pilbara down to the southwest.

At the end of the week, showers, thunderstorms, and squally winds continued to affect southern parts of Western Australia. The trough in the north moved east and produced moderate to locally heavy falls in the west Kimberley and Northern Interior.

Rainfall totals in excess of 200 mm were recorded around Mission Beach and Tully in the north tropical coast of Queensland, including the highest weekly total of 516 mm at Bingil Bay.

Rainfall totals in excess of 100 mm were recorded in pockets of the west Kimberley in Western Australia; small areas of the Hunter District in New South Wales; and the north tropical coast of Queensland.

Rainfall totals in excess of 50 mm were recorded the western Pilbara, and coastal areas of the Gascoyne and pockets of southwest Western Australia; from the north tropical to central coast, and adjacent inland districts of Queensland; areas in the Hunter and Illawarra districts in New South Wales; and far East Gippsland in Victoria.

Rainfall totals between 10 mm and 50 mm were recorded in the Kimberley, Pilbara, Gascoyne, Interior, South West Land Division and south coast of Western Australia; the northern half of the Northern Territory away from the northern Top End; most of Queensland except the southwest; central to eastern New South Wales; most of Victoria; southern and parts of eastern South Australia, and northern and western Tasmania.

Impact of recent rainfall on deficits

Rainfall deficits over Australia for the 9-month (August 2019–April 2020) and 25-month (April 2018– April 2020) periods are discussed in the Drought Statement, issued on 7 May 2020.

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 9-month and 25-month periods, extended to the week ending 26 May 2020.

Rainfall for the period 1 August 2019 to 26 May 2020

Areas of serious to severe rainfall deficiencies for the period starting 1 August 2019 persist in areas along the border of South Australia and New South Wales, extending in parts of western New South Wales; in pockets of southern South Australia and across the far north of that State, extending into the southwest of the Northern Territory; in far eastern Victoria and some parts of southeastern New South Wales; pockets of southwest coast and west coast of Western Australia; a large area in the central to northeastern Top End in the Northern Territory and far northern Kimberley; and pockets of eastern Queensland, including the inland southeast.

Rainfall over the past week eased deficiencies along the Central West coast of Western Australia, and in small areas of the Central Highlands in Central Queensland.

Affected areas in far western New South Wales, far northern South Australia and the south of the Northern Territory have generally received less than 40% of average, while remaining areas have received less than 60% of their average rainfall.

Rainfall for the period 1 April 2018 to 26 May 2020

Serious to severe rainfall deficiencies are in place for the 25-month period across much of the South West Land Division in Western Australia, parts of the Kimberley and the northeastern Interior District, and parts of the western Pilbara; much of the Northern Territory except areas of the east; much of South Australia; the southeastern quarter of Queensland; most of New South Wales; across northern Victoria and most of the eastern half of that State except parts of West and South Gippsland; and along the coast of northern and eastern Tasmania.

Areas of record low rainfall for the 25-month period persist in western New South Wales and adjacent eastern South Australia, areas along the New South Wales–Queensland border, parts of the southern coast of the South West Land Division and South Coastal District in Western Australia, and scattered pockets elsewhere.

The rain that fell in the past week had little impact on deficiencies at this time scale.

Affected areas through the interior of Australia into western New South Wales, southern inland Queensland, northeastern South Australia and the southern parts of the Northern Territory have generally received less than 50% of average rainfall for this period. Remaining areas have generally received between 80% and 50% of average rainfall.

Map of rainfall totals for this week

Product code: IDCKGRWAR0