While below average rainfall is likely in the east for the rest of December, most of Victoria has a neutral rainfall outlook for the first quarter of 2020.
That means there is no strong push from our climate drivers towards above or below average rainfall for January-March overall.
It is likely that the above average temperatures we've had in 2019 will continue into 2020.
January-March average maximum temperatures are likely to be higher than usual across the state, with the greatest chances over the north-east.
Nights are very likely to be warmer than average in the north-east, with chances decreasing to the south and west for January-March.
Two of the drivers of the recent warm and dry weather, the positive Indian Ocean Dipole (IOD) and the negative Southern Annular Mode (SAM), are likely to withdraw soon.
The positive IOD is weakening and will likely end in January.
Typically, a positive IOD means below average rainfall for much of central and southern Australia, and warmer than average temperatures for the southern two-thirds of Australia.
It is unusual for the IOD to persist far into summer, as it normally breaks down when the monsoon moves into the southern hemisphere in late spring or early summer.
The 2019 event has been exceptionally strong, and its decay hampered by a late movement of the monsoon into the southern hemisphere.
The negative SAM is likely to persist through to the end of December and then rapidly weaken.
At this time of year, negative SAM tends to bring warmer and drier conditions to parts of eastern mainland Australia.
Due to the lack of rainfall, low streamflows are likely at most forecast sites in Victoria from December-February, however, parts of southern Victoria have recorded average rainfall so far in 2019 and some sites in southern Victoria are likely to have near average streamflow over summer.
The updated Australian Seasonal Bushfire Outlook, issued December 16, shows East Gippsland and much of northern Victoria have above normal fire potential this season.
Fire potential depends on many factors including weather, fuel abundance and availability, recent fire history and firefighting resources available in an area.
The very warm and dry conditions in 2019 are key contributors to the above normal fire potential heading into 2020.
