Wettest autumn in decades
Most of Victoria has been wetter than average this autumn so far, and it is only parts of the far east that have been drier than usual. It is a similar story for New South Wales with above average rainfall across the interior but east of the Divide seasonal totals to date have been more typical or even below average in parts.
March and April did the heavy lifting; rainfall was in the wettest 10 per cent of records across much of southeast Australia away from the coast during April, following above average rainfall for much of the same area during March.
State-wide, autumn rainfall is on track to be the highest since 1989.
It has been a wet first five months of the year for most of Victoria but year to date totals are closer to average in the far northwest, southwest and eastern corners of the State.
The extra cloud has helped keep autumn days cooler than average for most of Victoria and much cooler than average in parts of the northeast. On average, overnight temperatures have mostly been typical for the season.
The outlook for winter is still favouring above average rainfall for much of central, northern and north-western Victoria. In the southwest and southeast there is roughly equal chance of above or below average winter rain.
The prospect of extra rainfall and cloud means days are likely to be cooler than average this winter in the northwest. But there are signs days could be warmer than usual in the east—a pattern that extends along the eastern seaboard from parts of Tasmania up to the tip of Cape York Peninsula.
One of the main drivers of this year's above average rainfall has been warmer than average water in the eastern Indian Ocean providing extra moisture to weather systems as they sweep across the country. Looking ahead, computer models are predicting a negative Indian Ocean Dipole (IOD) may develop during winter. And while the El Niño–Southern Oscillation (ENSO) is likely to remain neutral over winter, cooling towards La Niña levels is possible by the end of the season. Both La Niña and negative IOD events typically bring above average rainfall for parts of Victoria.