Australia: La Nina 2021 weather event declared in Pacific Ocean by Bureau of Meteorology

On November 23, the Bureau of Meteorology (BOM) in Australia has proclaimed a La Nina weather event, with the country's wettest spring in ten years expected to extend throughout summer. La Nina is part of the El Nino-Southern Oscillation (ENSO), which is a naturally occurring shift in ocean temperatures and weather patterns near the Pacific Ocean's equator, resulting in wetter conditions and more cyclones. Dr Andrew Watkins, the Bureau's Head of Operational Climate Services, said that tropical weather and heavy rains will lash the eastern, northern, and central areas of Australia throughout the summer months.

The quantity of cloud buildup and the strength of trade winds are among the factors they monitor. The agency took to Twitter to make the announcement. The caption read, "The Bureau has declared that a #LaNiña has developed in the tropical Pacific. Typically during La Niña, there is above average rainfall for eastern, northern and central parts of  Australia."

In October, the bureau issued a La Nina warning, stating that confirmation will come in November. The news comes just one day after the agency confirmed the creation of the first tropical storm of the season in Australia. According to current model forecasts, this La Nina will linger until late summer or early fall 2022 in the southern hemisphere, according to the bureau, extending the weather event's duration beyond earlier predictions that it would wane by the end of January.

Queensland, New South Wales, Victoria, and Tasmania are the states most expected to get considerable rain from now until January. According to the Bureau of Meteorology, Cyclone Paddy began near Christmas Island on Monday and intensified to a category one storm, although it will weaken by Wednesday and skirt landfall.

On Tuesday afternoon, the Bureau of Meteorology issued its fortnightly update of the primary climate factors for Australia's weather, which coincided with the announcement of a La Nina. It has been on a La Nina watch for weeks. It also issued flood warnings for rainfall expected to hit eastern Australia later this week.

Australia to face more cyclones this year

Eastern Australians, in particular, don't need much more proof that the weather has suddenly turned damp and chilly. While the Indian Ocean has a greater influence on the above-average rainfall experienced by many locations in the winter and spring, the Pacific has a greater influence in the summer. The east-west trade winds that travel over the equatorial Pacific intensify during La Nina years.

Rainstorms are successfully pushed westwards, increasing the risk of flooding and raising relative sea levels in the western Pacific. Such years also have a higher number of cyclones than typical. The bureau forecast last month that there was a two-in-three probability that Australia's region will get more than the seasonal average of 11. Last year, there was also a La Nina, and analysts estimate that there is a 40% likelihood of back-to-back incidents this year. The most recent doubleheader spanned the seasons 2010-11 and 2011-12.

(With inputs from agencies)

Image: AP/Representative