The winter outlook issued on Thursday, May 16, shows a warmer and drier than average season is likely for most of Victoria.
A frustrating forecast for parts of the state recovering from a dry start to the year following below average rainfall in 2018.
Parts of the south and southeast have a neutral rainfall outlook-the chance of above average seasonal rainfall is close to 50 per cent.
But as you move further north the chance of above average rainfall decreases, for example Geelong has a 46 per cent chance, while Bendigo has a 32 per cent chance and Swan Hill only has a 26 per cent chance of above average rainfall.
Days and nights are likely to be warmer than average in winter 2019.
The exception is the northwest where nights have roughly equal chances of being warmer or cooler than average.
The greatest chance for warmer days is in the north ( 80 per cent chance) but for nights it's in the southeast (again, 80 per cent).
The Bureau's climate model suggests the dry pattern in the outlook for Victoria is being driven by the increased chance of a positive Indian Ocean Dipole event during winter.
The current El Nio-like warmth in the Pacific is expected to cool in the coming months, easing the central tropical Pacific further into a neutral ENSO (El Nio-Southern Oscillation) phase by mid-winter.
If the models are correct, then the dry influence from the Indian Ocean is likely replacing the dry influence from the Pacific.
El Nio typically brings below average winter-spring rainfall to eastern Australia, while a positive Indian Ocean Dipole typically brings below average rainfall to southern and central Australia. When the two phenomena coincide, they can reinforce their dry impacts.
Root zone (0-1 metre depth) soil moisture is average to above average for most of Victoria after good rainfall from the first weeks of May.
But there are exceptions, including the East Central and West Gippsland districts, where soils remain drier than usual.
Natural stream flow is likely to remain lower than average through winter.
For more detail about the Winter Outlook, sign up for the next Bureau of Meteorology webinar to be held on Thursday, June 6, 11am-12pm AEST.
Hear from our climate experts on what is driving the climate, and how expected conditions might affect water availability and frost this winter. More details at www.bom.gov.au/webinars
- Jonathan Pollock, BOM climatologist
