THE CLIMATE KELPIE BLOG: What’s predicted in March?

Posted by BCG on 5th March 2021

The La Niña is now weakening with conditions in the tropical Pacific Ocean likely to return to neutral over the next three months. However, during this transition phase it is not uncommon for the effects of a La Niña to still be felt and hence northern and eastern regions of Australia could still experience ‘Above Average’ rainfall during autumn.

The Madden-Julian Oscillation (MJO) is currently weak but forecast to move into the tropical Americas and Africa in the coming week. When the MJO moves to this position northern Australia typically experiences ‘Below Average’ rainfall.

The Southern Annular Mode (SAM) has returned to neutral levels and models anticipate SAM to remain this way for the next couple of weeks. SAM’s influence is usually erratic through Autumn. The Indian Ocean Dipole (IOD) continues to remain neutral and isn’t expected to change from this state anytime soon. The IOD is not likely to influence Australia’s rainfall for the next few months.

The overall outlook for March to May is for increased chances of ‘Above Average’ rainfall for parts of eastern Queensland, New South Wales and Western Australia. A more ‘Average’ outlook is likely elsewhere. In terms of temperatures, minimums are likely to be ‘Above Average’ across most of Australia and maximums are likely to be ‘Above Average’ in the northern parts of Australia, Tasmania, and the west coast of Western Australia, however much of southern Australia is likely to be ‘Below Average’.

Rainfall Roundup

In February, rainfall was ‘Below Average’ in a northern Western Australia, along the south east coast of Queensland and much of western New South Wales, western Victoria and into South Australia however the rest of Australia received ‘Average’ to ‘Above Average’ rainfall during February (Fig. 1). The 2020-21 summer was the wettest since 2016-2017 with large areas of Western Australia and the Northern Territory as well as parts of northern Queensland, South Australia, the north coast and central regions of New South Wales, south west and north east Victoria as well as the north east of Tasmania all recording ‘Above Average’ rainfall (Fig. 2). However, some places did miss out including southern Queensland as well as small areas in the south of Western Australia, north west Victoria and into New South Wales and the south east of South Australia (Fig. 2).

Figure 1. Rainfall deciles for February 2021.
Figure 2. Rainfall deciles for December 2020 to February 2021.

Rainfall Forecast

The BoM’s ACCESS model predicts that in March ‘Above Average’ rainfall is likely in southern Australia and ‘Below Average’ in northern Australia (Fig. 3). For the three-month forecast, March to May, ‘Above Average’ rainfall is likely for much of Australia except for north west Queensland where ‘Below Average’ rainfall is likely (Fig. 3). At this time of year accuracy for the three-month forecast is moderate to high for much of Australia except for parts of central Australia, small pockets in Victoria and Tasmania was well as along the New South Wales and Queensland border (Fig. 3).

Figure 3. Australian rainfall outlook for March to May 2021.

Temperature Roundup

Maximum temperatures in February were ‘Average’ to ‘Below Average’ for much of Australia except for a pocket along the northern tip and much of the southern parts of Queensland where it was ‘Above Average’ (Fig. 4). Minimum temperatures were ‘Above Average’ over Queensland, parts of the Northern Territory and the Western Australia coastline, as well as a small area on the New South Wales central coastline, and the eastern coastline of Tasmania (Fig. 5). In contrast areas of ‘Below Average’ minimum temperatures were recorded in all states and territories except for Tasmania and Queensland (Fig. 5).

Figure 4. Maximum temperature deciles for February 2021.
Figure 5. Minimum temperature deciles for February 2021.

Temperature Forecast

The BoM’s ACCESS model forecast suggests that over the next three months maximum temperatures are likely to be ‘Above Average’ across northern Australia and ‘Below Average’ across southern Australia (Fig. 6). Some notable exceptions include Tasmania and the Western Australia coastline where maximum temperatures are likely to be ‘Above Average’ (Fig. 6). For minimum temperatures, most of Australia is likely to be ‘Above Average’ for the next three months apart from a large area in the south of Western Australia into South Australia which has equal chances of maximum temperatures being ‘Above’ or ‘Below Average’ (Fig. 7).

At this time of year accuracy for the three-month maximum temperature forecast is moderate to high for much of Australia except for the north west of Victoria, parts of South Australia and much of the southern half of Western Australia where accuracy is low (Fig. 6). For minimum temperature, accuracy is moderate to high across most of Australia except for parts of Queensland into northern New South Wales which have low accuracy (Fig. 7).

Figure 6. March to May 2021 maximum temperature outlook.
Figure 7. March to May 2021 minimum temperature outlook.

Climate and Water Outlook Videos

The Bureau of Meteorology releases regular outlook videos, covering all this information. Watch the most recent video below.

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