A return to normal rainfall

Welcome rainfall in the past week raised month-to-date totals above January averages in parts of northern, central and eastern Victoria. With a week left to go, much of the State will cruise past their normal January rainfall.

While the rain will help combat the longer-term severe rainfall deficiencies in parts of the east, the cold temperatures, rain and showers, and southerly winds triggered a warning to sheep graziers on Monday for the South West, Central and West and South Gippsland forecast districts.

Looking ahead, the climate model is showing us there's no strong push towards wetter or drier than average rainfall patterns over Victoria in the coming three months. The same goes for most of Australia. The climate model's 50:50 rainfall outlook is consistent with forecasts for a neutral El Niño–Southern Oscillation through autumn.

While the model doesn't favour widespread above or below average rainfall, the temperature outlook is more one-sided. Both days and nights are likely to be warmer than average from February to May across the State. The greatest chance of above average temperatures is in the east, reducing slightly towards the southwest. The outlook for warmer than average temperatures is consistent with the long-term increasing trend in global air and ocean temperatures.

The dry end to 2019 including below average soil moisture in catchments across the east, and neutral rainfall outlook for the beginning of 2020, means low streamflows are likely to continue at most Victorian forecast locations from January to March; there are no locations with high flows forecast. Much of the rain will first need to soak into the dry soils before we are likely to see substantial increases in streamflows.

Victorian water storage is about 45% full, which is about 9% lower than this time last year. But the two drainage divisions that cover Victoria, the Murray-Darling in the north and the South-East Coast, were affected by different conditions in 2019. Storage levels in the South-East Coast are 37.8 % full, an increase of 1.7 % over the past year, while storage levels in the Murray-Darling are 31.5 % full, falling 11.4 % over the past year. 2016 was the last year with well above average storage refilling in the Murray-Darling Basin.