Relief for California's devastating drought could be on the way later this year because an El Niño climate pattern is likely to develop in the Pacific Ocean, the National Oceanic and Atmospheric Administration (NOAA) reported Thursday.
El Niño, the planet's most important climate phenomenon, shakes up weather in the USA and around the world.
"There's a 65% likelihood that El Niño will develop by later in the fall," said Mike Halpert, director of NOAA's Climate Prediction Center. He said there's a 50% chance of it developing as early as the summer.
A forecast from the Australian Bureau of Meteorology earlier this week was even more confident, predicting at least a 70% chance of an El Niño in the next four months.
In the USA, a strong El Niño can result in a stormy winter along the West Coast, a wet winter across the South and a warmer-than average winter for parts of the North. "Overall, El Niños tend to bring warmer and wetter winters from coast-to-coast," Halpert said. That would be welcome news for many after this past harsh winter.
El Niños also tend to suppress hurricane activity in the Atlantic Ocean and Gulf of Mexico.
However, as noted by meteorologist Jan Null of Golden Gate Weather Services, El Niños don't automatically deliver more precipitation to California, and historically have done so only about half the time in central California.
During an El Niño, water temperatures in the central and eastern tropical Pacific Ocean get a few degrees warmer than average for an extended period of time – typically at least three to five months.
Much warmer-than-average water is currently building under the ocean surface. March temperatures for a good chunk of the eastern and central Pacific Ocean were the warmest for any March since 1979, Halpert said.
Some water under the surface is as much as 7 degrees F above average, the Australian meteorologists reported. With temperatures that far above normal, the upcoming El Niño could rival some of the most intense on record, including one in 1997-98.
That El Niño killed 23,000 worldwide due to floods, drought and disease and led to $35 billion in damages, according to a 1999 report from NOAA. It also pushed global temperatures to their highest on record, which could happen again this year or next.
Previous spring El Niño forecasts haven't always come true, including as recently 2012, Halpert said.
"It is very early to be predicting a major El Nino for next winter," Cliff Mass, a meteorologist from the University of Washington, wrote on his blog. "Our skill for predicting the next winter is substantially less before roughly July 1."