Summer days and nights are expected to be warmer than usual for 2019-20.
Early rainfall outlooks for summer suggest much of central Victoria may be drier than average, while the whole state is likely to see warmer days than what is considered normal.
In the run up to summer, the strong positive Indian Ocean Dipole (IOD) will continue to influence Australia's climate, while a negative Southern Annular Mode (SAM) is also likely to affect the southern half of the country.
Both the IOD and SAM typically bring warmer and drier conditions to the southeast mainland during spring.
Typically, a positive IOD means below average rainfall for much of central and southern Australia during spring, and warmer than average maximum temperatures for the southern two thirds of Australia.
This is certainly what we've seen so far this spring, with less rainfall than usual in September and October and higher than normal daytime temperatures.
The outlook for November shows the dry pattern continuing in the north of the state, with areas south of the divide having a more neutral outlook.
This pattern is at least partly due to the negative phase of the Southern Annular Mode (SAM), which is expected to arrive during the first half of November.
A negative SAM in spring tends to bring drier conditions to parts of eastern Australia including northern Victoria, but wetter conditions to western Tasmania.
Typically, a negative SAM increases the chance of spring heatwaves occurring across southern and eastern Australia.
We've already had some very warm days in October but the outlook for maximum temperatures in November is neutral for most of Victoria.
IOD events typically have little influence on Australian climate from December to April.
This means its contribution to the recent drier outlooks should start to reduce in early summer.
However, the current IOD event is so strong it is likely to take a little longer to break down.
While outlooks for drier than average conditions may ease for some areas in the coming months, several months of above average rainfall would be needed to see a full recovery from current long-term rainfall deficiencies in parts of south-east Australia.
For more information, visit www.bom.gov.au/climate/outlooks/
- Jonathan Pollock is a climatologist at the Bureau of Meteorology.
