Australian Bureau of Meteorology has just issued a La Niña alert

Renewed cooling in the tropical Pacific Ocean and models indicating a La Niña is likely by the end of the year have prompted the the Bureau of Meteorology to declare a La Niña alert—the last step before an official La Niña. 

A La Niña occurs when there are warmer than usual ocean temperatures in the western Pacific—near Australia—and cooler waters in the east.

"La Nina events increase the chances of above-average rainfall for northern and eastern Australia during spring and summer," the BOM website reads.

Rainfall this year is already being charged a negative Indian Ocean Dipole (IOD)—meaning the southern regions of Australia are likely to have a wet winter and spring—which has already been declared.

If a La Niña is declared, it would be the third one in a row.

While La Niñas occasionally occur in consecutive years, triple-dips are relatively rare, having only occurred twice since 1950.

La Niñas can form as early as autumn or as late as spring, and typically enhance rainfall through the summer severe weather season until autumn.

If a La Nina develops, it is likely to come into full bloom during the coming spring. 

This news comes after repeated flooding in Queensland and NSW in recent months.

The BOM declaration prompted warnings by the NSW State Emergency Service that there will be a heightened risk of flooding in the state.

On top of this, National water storage levels are currently sitting at 71.3 per cent, up 5 per cent on last year, while the Murray-Darling Basin is sitting at 92.2 per cent, up 12.4 per cent on this time last year—many dams up and down the east coast are now sitting at or over capacity.