Australia expects strongest El Nino since 1997-98

OREANDA-NEWS.  This year's El Nino weather phenomenon is expected to be the strongest since 1997-98, Australia's Bureau of Meteorology (BoM) said.

The 1997-98 El Nino was followed by the hottest year in the 20th century in 1998. The weather phenomenon in the southern part of the Pacific Ocean is now well established with further warming of the tropical part of the Pacific likely in the coming months. El Nino is likely to remain in place for the rest of this year, BoM said.

Recent tropical cyclone activity, including a rare July southern hemisphere cyclone in the western Pacific, has brought about a strong reversal of the Pacific trade winds resulting in enhanced warming of sea surface temperatures (SSTs) across the Pacific.

The latest SSTs measurements have been the strongest since 1997-98. All models indicate SSTs in the central tropical Pacific will exceed 2°C above average by October, with an all-model average temperature anomaly of 2.6 °C above average, BoM said.

Average temperatures across global land and ocean surfaces in June were 0.88°C above the 20th century average, the US National Oceanic and Atmospheric Administration (NOAA) said. "This was the highest for June in the 1880–2015 record, surpassing the previous record set last year in 2014 by 0.12°C," NOAA said.

This year's El Nino was first declared in May. This is earlier than usual, as the phenomenon is not normally declared until at least mid-year. El Nino is a warming of the Pacific Ocean surface that occurs naturally every few years. It can trigger droughts and floods in most countries along the Pacific coastline, but its impact can be felt in the Indian Ocean and as far away as east Africa.

The weather disruption can affect energy demand and supply flows. Higher temperatures during the winter months in Australia can reduce heating demand, while droughts in other parts of the world can affect hydropower generation.

El Nino is typically associated with below-average winter and spring rainfall over eastern Australia and above-average daytime temperatures over the southern half of the country during the second half of the year. Lower rainfall could affect hydropower generation in New South Wales and higher temperatures could reduce winter heating demand.