A very dry month for the southeastern mainland increases rainfall deficiencies
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.
Rainfall deficiencies persist; increase in parts of the east and north
January rainfall was below or very much below average across the southeastern quarter of Queensland, northeastern New South Wales, Victoria and adjacent southern New South Wales, southern South Australia, Tasmania, most of the southern half of Western Australia, most of the Northern Territory (except the Top End) and adjacent western Queensland. A large number of stations in the southeastern quarter of Queensland received record-low rainfall for January.
Rainfall was very much below average for southern Victoria and much of southern South Australia, while for Tasmania as a whole it was the driest January on record.
Tropical systems contributed to above average rainfall along the coast of central and northern Queensland, and small in central northern Queensland and the Top End, and central eastern New South Wales.
The delayed onset of the Australian monsoon during the summer of 2018–19 has seen below average rainfall for the northern wet season to date over most of northern Australia, excluding Queensland's tropical and central coast, and the northeastern Top End. This has led to the emergence of serious or severe rainfall deficiencies over parts of northern Australia at the 4-month timescale.
A slow-moving monsoon trough has produced, and will continue to produce, heavy rain across northern Queensland during late January to early February. Multi-day totals for the first 5 days of February exceeded 400 mm across a broad area, and while the heaviest rain has so far been on the coast in the region surrounding Townsville, there have been locally very high (but patchy) falls in inland northern Queensland, including an area north of Mount Isa. It is likely that a Special Climate Statement will be released for this event.
Rainfall has been below average over the region for a number of months (periods beginning April 2018) and the deficits in place are quite large. While this current event will go far towards relieving rainfall deficiencies, and may remove short-term deficiencies (particularly immediately north of Mt Isa), is unlikely to clear long-term deficits completely, and some areas will miss out.
The lack of rainfall over northern Australia during summer has also been a primary influence on the prolonged heat events which have affected Australia since early December 2018. Both the scale and longevity of this persistent heat is unprecedented and January was the warmest on record for Australia; further information can be found in the Special Climate Statement Widespread heatwaves during December 2018 and January 2019.
Rainfall deficiencies for the longer 10-month period have also increased across northern Australia, and have generally increased slightly across eastern South Australia and the eastern mainland at both the 10- and 22-month timescales.
4-month rainfall deficiencies
Northern Australia receives the bulk of its rainfall between October and April (the northern wet season), so rainfall deficiencies during this period are particularly significant, and will not usually be removed before the following wet season.
For the 2018–19 northern wet season so far, rainfall has been below average over most of northern Australia, excluding Queensland's tropical and central coast, and the northeastern Top End. Serious or severe rainfall deficiencies for the period starting October 2018 affect scattered pockets of the north of Western Australia, a large area in the central Northern Territory and smaller areas spanning the border and adjacent parts of western Queensland, and an area inland of the ranges in the southeastern quarter of Queensland.
Rainfall during this period has also been particularly low over Tasmania, with severe deficiencies across the west of the State.
10-month rainfall deficiencies
Southern Australia receives the bulk of its rainfall between April and November (the southern wet season), so rainfall deficiencies during this period are particularly significant.
While December brought above average rain for parts of the mainland southeast, high rainfall after the end of the main agricultural and runoff season has the effect of reducing rainfall deficiencies, but does not fully ameliorate the impact of earlier dry conditions.
January was very dry across large areas, and has seen deficiencies increase across much of eastern Australia and increase greatly across northern Australia.
Serious or severe rainfall deficiencies are in place across eastern South Australia (except the extreme southeastern tip) and adjacent parts of western New South Wales; across northern New South Wales away from the coast, and an area in the South West Slopes and Riverina districts; across Gippsland in Victoria; much of Queensland except the far southwest, Cape York Peninsula, and much of the central coast; a large part of the Northern Territory between the eastern border and central regions; an area of Western Australia in the southern Kimberley and northern Interior, and smaller areas in the northern Kimberley and in the Southeast Coastal District.
22-month rainfall deficiencies
As for the other periods, low January rainfall has generally seen rainfall deficiencies increase slightly, and emerge across parts of the Northern Territory.
Serious or severe rainfall deficiencies continue across most of New South Wales excluding the northeast coast and most southern regions away from the far southwest and inland of the coastal ranges; across much of eastern Victoria; areas of coastal eastern and northern Tasmania; much of the eastern half of South Australia away from the far southeast and far northeast; much of the southern and central Queensland away from the coastal ranges, and areas of western Queensland extending into parts of the Alice Springs and Barkly districts in the Northern Territory.
In Western Australia deficiencies persist along the coast between the Pilbara and the South Coastal District.
Compared to December, relative lower-layer soil moisture (from 10 cm to 100 cm deep) has decreased across nearly all of Australia.
Soil moisture for January was below average for the western half of Western Australia, across the Nullarbor and in pockets of the Kimberley; across most of the remainder of the mainland except for some areas in the west of the Northern Territory and central to eastern Top End, the northwest of South Australia, across the north and east of Cape York Peninsula and central coast Queensland, pockets of central eastern to southeastern New South Wales, northwestern Victoria, and northeastern Tasmania.
Soil moisture was above average for the north and east of Cape York Peninsula and pockets of Queensland's central coast, and also for pockets of the north east of the Top End, in the east of Western Australia in the north and south of the Interior District, and on the west coast near Geraldton.
- January rainfall very much below average for southeastern Queensland and much of southeastern Australia; driest January on record for Tasmania
- Rainfall above average for parts of northern coastal Queensland
- Short-term deficiencies have increased and are evident in western Tasmania and scattered areas of northern Australia at the 4-month timescale
- Deficiencies have increased at the 10-month timescale in much of eastern South Australia, the eastern mainland, and northern Australia
- Longer-term deficiencies continue with generally slight increases in most areas
- Lower-level soil moisture below average for January across most of Australia, except central west of Western Australia, parts of the Top End, and the northern and central Queensland coast
- Record-high temperatures added to moisture stress during January, following a record-warm December
Product code: IDCKGD0AR0