A drier than normal autumn is predicted for large areas of Queensland and southeastern Northern Territory, while southern and western parts of Western Australia are set to receive a wetter than normal three months ahead, according to the Bureau of Meteorology’s latest Seasonal Climate Outlook.
The forecast for March to May rates the chances of exceeding median rainfall at less than 40pc for parts of central and western Queensland and the southeast corner of the NT.
“For every ten autumn outlooks with similar odds to these, about three or four of them would result in above-average rainfall over these areas, while about six or seven would be below average,” the Bureau explains.
Conversely, the chance of exceeding the median rainfall is greater than 60pc over the western half of WA, and a small area in northeast of the NT.
Over the rest of the country, there is no significant shift in the odds towards either a wetter or drier than normal autumn.
The forecast is based on several contributing factors including an El Niño-Southern Oscillation (ENSO) that remains neutral. The majority of atmospheric and oceanic indicators continue to track close to their long-term average.
Dynamical models surveyed by the Bureau suggest that while ENSO-neutral conditions are likely to persist through autumn, some warming of the central Pacific Ocean is likely. While short of El Niño levels, this warming may still have some impacts upon Australian climate.
Ocean temperatures surrounding Australia are generally expected to remain close to their 1981-2010 average, though some cooler than average temperatures around northern and north-eastern coasts early in the season may mean a reduction in evaporation in those areas.
Atmospheric pressures may be below average over some southern areas in the first half of the season, which may favour drier westerly winds over some parts of eastern Australia.
The Indian Ocean Dipole is typically too weak to have a significant influence on the Australian climate during the autumn period.
In terms of temperatures, cooler days and cooler nights are more likely over the northern half of the NT and the Kimberley region of WA over the next three months, and warmer days are more likely across southern Victoria and Tasmania.
The Bureau says the outlook accuracy is moderate to high over much of eastern and central Australia, except for some areas near the WA/NT border, southern parts of SA and western parts of WA where the accuracy is low.