For now,the Great Barrier Reef is"very much in a watch situation",said James Kerry,the acting chief scientist of the reef's Marine Park Authority.
The past winter was cooler than the previous year's giving"a bit more buffer in the system",Dr Kerry said.
Still,the Bureau of Meteorology's forecasts indicate areas such as the Capricorn and Bunker reefs off Gladstone may reach the threshold of heat stress that could trigger bleaching.
“For the southern half of the Great Barrier Reef,there’s a reasonable probability over the January-March period we will see heating in that range,"Dr Kerry said.
“That is the kind of borderline[level] where you can start to see coral bleaching once you’re getting over the four-week mark,"he said ."That’s a concern."
Benjamin Fitzpatrick,a coral biologist with the University of WA and director of Oceanwise Australia,said researchers were"fairly certain we will see a significant bleaching event this year".
The most recent significant bleaching at Ningaloo was in 2011 and should the NOAA and bureau predictions hold,this summer's event could be as bad or worse,he said.
Climate change,which was pushing up background temperatures,meant such the risks of such events was increasing.
Dr Fitzpatrick said the warming would impact the whale sharks that underpin the ecotourism industry in the region.
“At this stage,we really need to reduce our greenhouse gas emissions and reduce the warming that is occurring,"he said.
Dr Kerry said there was not much authorities could do to limit any bleaching should it occur. But ongoing investment in improving water quality or tackling the Crown of Thorns starfish would have give the reef greater resilience and aid in its recovery after a bleaching event.
However,Dr Fitzpatrick said that"in many instances even with good management plans in place we are seeing dramatic and rapid loss of coral cover due to these global impacts.
“We are still finding that climate change and warm water can wipe out all those management gains,"he said.
Andrew Watkins,head of long-range forecasts for the Bureau of Meteorology,said the warming up of the seas to Australia's north-west appears to be the result of a complex interaction.
Warmer waters are passing from the Pacific Ocean through the Indonesian archipelago and into the Indian Ocean,driven by increased trade winds. A big area of lower-than-normal air pressure over the southern Indian Ocean is also weakening winds that would usually be drawing cool waters north,Dr Watkins said.
And the months'long pattern of reduced cloud cover off north-western WA - that have contributed to reduced rainfall and drought in south-eastern Australia - has led to a warming of shallow waters near the coast.