The chances of a La Niña weather event occurring this year has increased to 70% according to the Bureau of Meteorology, this is roughly three times the normal outlook.

La Niña means higher than average rainfall in the central, eastern and northern parts of Australia.

Dr Andrew Watkins the Bureau of Meteorology Manager of Climate Operations said "It typically also brings cooler and cloudier days, more tropical cyclones, and an earlier onset of the first wet season across the north".

The last significant La Niña event occurred in 2010/11, which was Australia's wettest two year period on record beating the previous record of 1973/74.

During both of those periods severe flooding occurred.

2010/11 saw Brisbane suffer major flood damage as homes were ripped off their foundations and swept down river while some people in Lismore will remember the floods of 1974. The memories of the more recent 2017 floods very much in the forefront of all our minds.

The long term forecast from the BOM is not to say that major flooding will occur but to say there is an increased chance of higher than average rainfall.

The impacts of La Niña often continue into the warm months. In eastern Australia, the average December-March rainfall during La Niña years is 20% higher than the long-term average, with eight of the ten wettest such periods occurring during La Niña years. This is particularly notable for the east coast, which tends to be less affected by La Niña during the winter months but can experience severe flooding during La Niña summers.

The reason is the cooling of surface temperatures in the tropical Pacific Ocean and an increase in the strength of the Pacific Trade Winds. When these two changes occur at the same time, at this time of year, we see a greatly increased chance of a La Niña forming and persisting through spring and into summer.

"Climate models suggest that further cooling and intensification of Trade Winds may occur over the coming months, which has triggered the Bureau to shift from a La Niña watch, issued on 26 June, to a La Niña Alert", Dr Watkins said.

In the short term, our clear blue winter skies will continue for the next seven days with some fairly strong westerly winds turning north westerly this afternoon. This will be the pattern into the weekend with some cloud about.