Just days after La Niña was officially declared in Australia, a week-long, multi-state rain event is about to hit the country.

The Bureau of Meteorology issued a statement on Tuesday declaring that La Niña had become established in the Pacific Ocean. La Niña refers to a pattern of sea surface temperature and wind anomalies in the equatorial Pacific that increases the likelihood of rain in some parts of Australia, amongst other effects.

Now, just days after La Niña became established, computer models suggest that a significant amount of rain will fall over a broad area of Australia between this weekend and next weekend.

Image: Forecast accumulated rain between now and next Sunday, according to the ECMWF-HRES model.

An upper-level trough interacting with tropical moisture will cause a band of rain to develop over southern and central Australia this weekend. The heaviest falls will occur in South Australia and Tasmania, where some places could pick up over 30mm of rain by Sunday night.

From Monday, a region of upper-level cold air will become cut off over southern Australia and remain near-stationary for a few days, before moving further east. This stagnant pool of cold air will continue to interact with a persistent stream of tropical moisture to produce widespread rain and thunderstorms.

Next week's wet and stormy weather will affect parts of every state and territory, although the heaviest rain should fall in parts of northern, central, and southeastern Australia.

Some parts of the Australian outback could see one or two month's worth of rain in a matter of days from this system. This comes after record-breaking rain fell in parts of central Australia last month.

In addition to the rain and storms, this dynamic system could also cause damaging winds. Be sure to keep up to date with the latest warnings in your state or territory this weekend and next week.