Should forecasts be realised it would be the biggest anomaly since 1997, surpassing the top recordings of 2002 and 2009

* Sea-surface temperature anomalies in central Pacific to climb

* El Nino will likely persist until early 2016

By Colin Packham

SYDNEY, Aug 4 (Reuters) - An El Nino is now well established and continues to strengthen, the Australian Bureau of Meteorology (BOM) said, with models indicating that sea-surface temperature anomalies in the central Pacific Ocean are set to climb to the highest in 19 years.

The El Nino, marked by a warming of sea-surface temperatures in the Pacific, can lead to scorching weather across Asia and east Africa but heavy rains and floods in South America.

"This past week the central tropical Pacific is 1.6 degree Celsius above normal, and slowly warming still - and forecast by models to continue warming," Andrew Watkins, supervisor, Climate Prediction Services at the BOM, said on Tuesday.

"Remember, peak values typically occur late in the year so we have a three to seven months to go before we may peak in the current event. The 1987 (event) peaked in August - all other events peaked between November and February," said Watkins.

Further warming is likely, according to models monitored by the BOM, with an average peak reading of +2.7 degree Celsius above normal by December expected.

Should that forecast be realised, it would be the biggest anomaly since 1997, surpassing the top recordings associated with the El Ninos of 2002 and 2009, data from the BOM shows.

The 1997 El Nino was the last "very strong" event recorded, though the BOM concluded the overall impact to be weak, with major crops withstanding much of the dry weather associated with the system.

The outlook reinforces the BOM's view that the developing El Nino could be a "significant event", threatening Australian production of staple crops such as wheat and sugar, and providing further pressure on the country's cattle farmers.

With the El Nino event still developing, the BOM said the weather event will likely persist until early 2016. (Reporting by Colin Packham; Editing by Himani Sarkar)

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