Victoria's west in for above average rain in April

Victoria's west in for above average rain in April

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The long-range outlook for April to June shows slightly increased chances of above average rainfall for western Victoria, while East Gippsland could see less rainfall than normal. Photo by Shutterstock.

The long-range outlook for April to June shows slightly increased chances of above average rainfall for western Victoria, while East Gippsland could see less rainfall than normal. Photo by Shutterstock.

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Australia's major climate drivers are likely to remain neutral through winter.

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Australia's major climate drivers - the El Nio-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) - are likely to remain neutral through winter.

When ENSO and the IOD are neutral they typically have little, if any, large scale influence on Australian rainfall and temperature patterns.

But even with these big climate drivers doing little to push our weather one way or another, the next fortnight is likely to be wetter than average for large parts of south-eastern Australia, including Victoria.

For April, western Victoria could see above average rainfall.

The long-range outlook for April to June shows slightly increased chances of above average rainfall for western Victoria, while East Gippsland could see less rainfall than normal.

There are roughly equal chances that days will be warmer or cooler than average for April overall.

However, the three-month April to June outlook indicates eastern Victoria is likely to have warmer days than usual.

Parts of northern Victoria are likely to have warmer than average April nights, and that expands to the whole state (and country) for April to June.

With our major climate drivers being neutral, there are other factors are influencing the outlook.

Typically in the autumn after a positive IOD (we had one of the strongest on record IOD events last year), warmer than average ocean temperatures in the tropical eastern Indian Ocean bring more northwest cloud-bands - those long lines of cloud that cross the country from north-west to south-east.

This draws moisture from the tropics right down to Victoria.

If this moisture meets a cold front or low-pressure system, it can trigger good rainfall, resulting in wetter than average conditions for Australia's south-east.

Warmer than average oceans around the coastline are also likely contributors to the warmer than average outlook across Australia.

Australia's temperature and rainfall variability are also influenced by long-term trends in our climate.

Australia's climate has warmed by about 1.4 degrees since 1910, and there has been a decline of about 11 per cent in April-October rainfall in the south-east of Australia since the late 1990s.

The BoM's climate model includes the influence of climate change and natural climate drivers like ENSO, IOD, and the Southern Annular Mode in its outlooks.

  • Jonathan Pollock is a BoM climatologist
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