A weak La Niña is predicted to persist in the tropical Pacific through the southern summer, and decay in the early southern autumn of 2018 by most climate models.

In its latest El Niño-Southern Oscillation (ENSO) Wrap-Up, the Bureau of Meteorology (BoM) said sea surface temperatures in the central to eastern tropical Pacific remain around La Niña levels, while in the atmosphere, cloud patterns also remain typical of La Niña. There has been a recent weakening in the trade winds, however, as well as a drop in the Southern Oscillation Index (SOI), but these likely resulted from a Madden-Julian Oscillation event and are not considered a signal of an early La Niña breakdown. What suggests the likely end of the event in the coming months was the build-up of warmer water beneath the surface of the western Pacific, BoM said.

La Niña typically brings above-average rainfall to eastern Australia during summer, but since a weak event is expected, it will likely have less influence on Australian rainfall. La Niña may also mean prolonged warm spells in southeast Australia.


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