In a monthly report from the National Climate Prediction Center, the National Centers for Environmental Prediction, the National Weather Service and the International Research Institute on Climate and Society, the chances of an El Niño developing this fall have decreased to 65 percent.
Computer forecast models delayed the onset of the El Niño, a warming of sea surface temperatures and corresponding atmospheric changes. Last month, the chance of the phenomenon forming was almost 80 percent through the Northern Hemisphere’s fall and winter.
An El Niño is characterized by unusually warm ocean temperatures in the Equatorial Pacific. That contrasts with the unusually cold temperatures in the Equatorial Pacific during a La Niña. Both are associated with extreme weather around the globe.
Scientists this spring saw signs that the 2014 El Niño might be as powerful as the devastating 1997-98 event that was blamed for thousands of death and more than $33 billion in damages. The strength of an El Niño is determined by the interaction between the winds and waves; the systems are classified as either weak, moderate or strong.
If an El Niño develops later this year in the Pacific, the jet stream across the U.S. could change this winter, meaning more rain and storms across the South while the Northeast may trend a little warmer.
Around the world, El Niños have been known to soak southern Brazil, dry out Southeast Asia and bring havoc to Australia. In the short term, it may even mean an early end to the Atlantic hurricane season by increasing the amount of wind shear across the basin.
“Over the last month, model forecasts have slightly delayed the El Niño onset, with most models now indicating the onset during July-September, with the event continuing into early 2015,” the report said.
It’s worth noting the Australian Bureau of Meteorology concluded last week that “the chance of El Niño developing in 2014 is approximately 50%, which remains significant at double the normal likelihood of an event.”
Despite the decreased odds, an “El Niño watch” continues, which means conditions are favorable for it to develop over the next six months. However, computer models are leaning toward a weak El Niño when and if one develops.