Rainfall deficiencies develop in southern Queensland after a dry April
April rainfall was below to very much below average across large parts of Queensland, eastern and central regions of the Northern Territory, southwestern Western Australia, eastern New South Wales and much of Tasmania. This has led to the development of short-term rainfall deficiencies across southwestern Queensland.
Rainfall was above average for central Western Australia, much of South Australia, western New South Wales and western Victoria.
6-month rainfall deficiencies
A drier than average April across Queensland has seen a renewal of rainfall deficiencies in some areas. Scattered pockets of serious and severe deficiency are present at the 6-month time scale across inland areas in the southern half of Queensland. Above average rainfall across eastern Queensland and northeastern New South Wales in March, due to tropical cyclone Debbie, had removed areas of deficiency that had developed in the region since the start of the Northern Wet Season in November. However, dry conditions persisted across inland areas that did not receive rainfall from this system. This is the fifth consecutive wet season with drier-than-average conditions for many areas in central and western Queensland.
Isolated pockets of serious rainfall deficiencies persist in East Gippsland in Victoria at the 6-month time scale.
3-month rainfall deficiencies
A drier than average April across much of Queensland saw the development of 3-month severe and serious deficiencies in southwestern Queensland, southeastern parts of the Northern Territory and surrounding areas. The second half of the northern wet season (February to April) has been drier than average over a large region covering much of the southern half of the Northern Territory, northern parts of South Australia, much of Queensland, excluding southeastern coastal regions and northwest New South Wales. After a drier than average February across much of New South Wales and Queensland, above average rainfall in March, largely due to tropical cyclone Debbie, relieved 5-month deficiencies in coastal regions, but continued dry conditions in April has led to the development of extensive areas of short term deficiencies at the 3-month time scale in inland areas.
Deficiencies are also present across much of Tasmania at the 3-month time scale, and although this was a climatologically drier time of the year for southern parts of Australia the situation will continue to be monitored.
Soil moisture in the lower layer (from 10 cm to 100 cm deep) increased across western Victoria, eastern parts of Queensland and New South Wales for April compared to March, but decreased across parts of central to western Queensland and southwestern Western Australia.
Soil moisture for April was below average for large areas of Queensland south of the Cape York Peninsula away from eastern coastal areas, southwestern Western Australia, eastern parts of the Northern Territory and small areas in western New South Wales and Tasmania.
Soil moisture for the month was above average for most of Western Australia, the west of the Northern Territory and the Top End, an area of western Victoria, and large parts of the east coast impacted by tropical cyclone Debbie in March.
- April rainfall was below average for much of Queensland, the Northern Territory, Tasmania and southwest Western Australia
- Serious to severe rainfall deficiencies are present at the 3-month timescale in the Northern Territory into southwestern Queensland and surrounding areas
- Soil moisture is below average across much of Queensland and western parts of the Northern Territory
Product code: IDCKGD0AR0
Soil moisture details are reported when there are periods of significant rainfall deficits.
Soil moisture data is from the Bureau's Australian Water Resources Assessment Landscape (AWRA-L) model, developed through the Water Information Research and Development Alliance between the Bureau and CSIRO.
See: Australian Landscape Water Balance.
What is drought?
Drought is a prolonged, abnormally dry period when the amount of available water is insufficient to meet our normal use. Drought is not simply low rainfall; if it was, much of inland Australia would be in almost perpetual drought. Because people use water in so many different ways, there is no universal definition of drought. Meteorologists monitor the extent and severity of drought in terms of rainfall deficiencies. Agriculturalists rate the impact on primary industries, hydrologists compare ground water levels, and sociologists define it by social expectations and perceptions.
It is generally difficult to compare one drought to another, since each drought differs in the seasonality, location, spatial extent and duration of the associated rainfall deficiencies. Additionally, each drought is accompanied by varying temperatures and soil moisture deficits.
Rainfall averages, variability and trends
- Average rainfall: How much rain do you expect?
- Rainfall variability: How consistent is rainfall in your area?
- Rainfall history: Check tables, graphs and data from your local weather station.
- Rainfall trends: Has your rainfall changed?
Lowest on record - lowest since at least 1900 when the data analysed begin.
Severe deficiency - rainfalls in the lowest 5% of historical totals.
Serious deficiency - rainfalls in the lowest 10% of historical totals, but not in the lowest 5%.
Very much below average - rainfalls in the lowest 10% of historical totals.
Below average - rainfalls in the lowest 30% of historical totals, but not in the lowest 10%.
Average - rainfalls in the middle 40% of historical totals.
Above average - rainfalls in the highest 30% of historical totals, but not in the highest 10%.
Very much above average - rainfalls in the highest 10% of historical totals.
For the week to 23 May 2017 rainfall was recorded in southwest and southern Western Australia, southern and eastern South Australia, most of Victoria and Tasmania, New South Wales, Queensland, and an area in the northeast of the Northern Territory.
At the beginning of the week, a low pressure system in the Great Australian Bight and an associated surface trough produced light falls along much of the southern coastline of Australia, and thunderstorms over central and northern parts of South Australia and southwest Queensland.
The low became cut off while the surface trough extended north towards the Gulf of Carpentaria and a cloudband with embedded thunderstorms formed east of the trough with embedded thunderstorms. Moderate falls were received in southeastern South Australia, western Victoria, western New South Wales and southwest Queensland. Further moderate falls were recorded over southern and southeastern Queensland, the eastern half of New South Wales and eastern Victoria.
Moderate to heavy falls were recorded in the north and northeast of Tasmania as the surface trough moved towards the southeast and deepened ahead of an approaching front towards the end of the week. As the cold front tracked across southwest Western Australia it produced light to moderate falls across the South West Land Division and southern coast of Western Australia.
In central to northern Queensland, a surface trough over the Coral Sea approaching the coast combined with an upper-level feature early in the week. Moderate to heavy rainfall totals were recorded from the Gulf Country, across the northern Queensland interior, and in areas from the southern tropics into central Queensland.
Isolated thunderstorms also formed in northeastern parts of the Northern Territory during the second half of the week.
Rainfall totals in excess of 100 mm were recorded in northeastern Tasmania, small pockets of southeastern New South Wales, and in the northern interior and southern tropics of Queensland. Parts of this area in Queensland observed totals in excess of 200 mm. The highest weekly total was 252 mm at Alva Beach, on Queensland’s central coast.
Rainfall totals between 50 mm and 100 mm were recorded around Perth in southwest Western Australia, pockets of western and far eastern Victoria, small areas of western and southeastern New South Wales, and in the northwest and northeast of northern Tasmania. Similar totals were recorded in isolated areas of southwestern and southeastern Queensland, across most of Queensland’s northern interior and along the east tropical coast from Cairns to St Lawrence.
Rainfall totals between 10 mm and 50 mm were recorded in southwest Western Australia; parts of southern, southeastern and northeastern South Australia; western and northern Victoria and East Gippsland; most of New South Wales except the northwest; and much of Tasmania except the southeast. Similar totals were recorded in southern, eastern and northern inland Queensland, and in parts of the coastal northeast of the Northern Territory.
Little or no rainfall was recorded in remaining areas of Western Australia, most of pastoral South Australia, central southern Victoria and West Gippsland, northwestern New South Wales, northwestern and central western Queensland and areas of inland southeastern Queensland.
Impact of recent rainfall on deficits
The Drought Statement, issued on 4 May 2017, discusses rainfall deficits over Australia for the 6-month (November 2016–April 2017) period. The rainfall deficit map is available for this period 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 3- and 6-month periods ending 23 May 2017.
Rainfall for the period 1 November 2016 to 23 May 2017
For the 6-month period (November 2016–April 2017), pockets in the southern half of Queensland were in serious to severe rainfall deficiencies.
Rainfall for the affected areas of southern and central western Queensland was less than 40% to 60% of the average for the period. An area of East Gippsland in Victoria has reported less than 80% of the average.
The rainfall that occurred during the week had little effect on deficiencies in southern Queensland.
Rainfall for the period 1 February 2017 to 23 May 2017
For the 3-month period (February 2017–April 2017) severe to serious deficiencies were evident in southwestern Queensland, southeastern parts of the Northern Territory, and surrounding areas. Deficiencies were also present across western and northeastern Tasmania.
Affected areas of the southeastern Northern Territory, northeastern South Australia and far southwestern Queensland reported less than 20% of average rainfall for the period. Heading east into the Mulga Lands, rainfall for the period rises to 20% to 40% of average. Affected areas in Tasmania reported less than 70% of average for the period.
Rainfall during the week eased deficiencies in affected areas of southwestern Queensland, and Tasmania.
Product code: IDCKGRWAR0