Rainfall Update

For the week to 21 April 2020, rainfall was recorded in southwest Western Australia, the coastal Top End of the Northern Territory, the Cape York Peninsula as well as eastern Queensland and adjacent inland districts, southeast coastal areas of South Australia, southern and northeastern Victoria, and Tasmania. Little to no rainfall was recorded elsewhere.

In the first half of the week, a slow-moving high pressure system in the northern Tasman Sea extended a ridge along the east coast, with showers in a moist onshore flow producing moderate falls across the north tropical Queensland coast, Cape York Peninsula, and the coastal Top End of the Northern Territory. In the south, a cold front tracked across southeast Australia, with a fresh west to southwesterly airstream persisting across Victoria and Tasmania. Moderate falls were reported in western Tasmania.

By the middle of the week, another cold front tracked across the southeast, bringing further moderate falls to western Tasmania. Showers continued along the northeast Queensland coast in onshore flow, and thunderstorms produced moderate falls about the Cape York Peninsula.

In the second half of the week, a surface trough extended inland from the Queensland coast, and showers and thunderstorms developed from the north tropical to Wide Bay and Burnett coasts, producing moderate falls. Severe thunderstorms produced giant hail of more than 7 cm in diameter in parts of the Capricornia District in Queensland.

A cold front and pre-frontal trough tracked across southwest Western Australia and produced moderate falls in the southwest and parts of southern coast of that State. The cold front tracked across the Southern Ocean and then southeast Australia at the end of the week, producing light falls in southern and southeast coastal parts of South Australia, and widespread light falls across most of Victoria except in the northwest. Moderate falls were also recorded in northern and western Tasmania as the cold front crossed that State.

Rainfall totals in excess of 100 mm were recorded in western Tasmania and about the north tropical coast of Queensland. The highest weekly total was 230 mm at Tully Sugar Mill in northern Queensland.

Rainfall totals in excess of 50 mm were recorded in parts of the north tropical and Burdekin coasts of Queensland, and the western half of Tasmania.

Rainfall totals between 10 mm and 50 mm were recorded in southwest and parts of the southern coast of Western Australia, the coastal Top End of the Northern Territory, much of the Cape York Peninsula, and from the north tropical coast to the Wide Bay and Burnett Districts and adjacent inland districts of Queensland.

Impact of recent rainfall on deficits

Rainfall deficits over Australia for the 8-month (August 2019–March 2020) and 24-month (April 2018– March 2020) periods are discussed in the Drought Statement, issued on 8 April 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 8-month and 24-month periods, extended to the week ending 21 April 2020.

Rainfall for the period 1 August 2019 to 21 April 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 had little impact on deficiencies in affected areas.

Affected areas of southwest Queensland and far northeastern South Australia have now received their average rainfall for this period. 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 21 April 2020

Serious to severe rainfall deficiencies are in place for the 24-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 24-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.