California drought: El Niño not likely to bring much rain
Pattern gathering out in Pacific expected to be 'weak to moderate'
Updated 5:06 pm, Thursday, July 10, 2014
Professional weather watchers are losing hope that the expected arrival of an El Niño in coming months will wash away California's drought.
The U.S. Climate Prediction Center, which issued its monthly report on Pacific Ocean weather patterns Thursday, is still projecting that sea surface temperatures will rise, a phenomenon known as El Niño. But the El Niño that's in the forecast will likely be "weak to moderate," the report says.
While strong El Niños have been associated with California's wettest years, lesser El Niños have not been linked to rainfall in Northern California.
"We're a lot less certain about what types of impacts we'll have this year," said Logan Johnson, a meteorologist with the National Weather Service who has been tracking the development of the El Niño. "Unless it's a strong event, it doesn't do much to predict what winter rainfall will be."
The chance of an El Niño emerging, according to the report, is about 70 percent by the end of summer and 80 percent by fall or early winter.
The projected strength of the El Niño is low because subsurface ocean temperatures near the International Date Line have cooled since earlier this year, according to the report.
Reports last spring of sea surface warming had many hoping that a strong El Niño would develop and help combat the state's prolonged drought.
While rainfall in Northern California isn't likely to see a bump with the El Niño, moderate events have sometimes correlated with wetter years in Southern California.
The strong events have correlated with statewide increases in rainfall. San Francisco saw its most rain in the last century - 47.2 inches - during the El Niño year of 1997-98.
California is wrestling with three years of below-average rainfall, and Sierra snowmelt remains historically light. That's left water supplies in many places at near-record lows.
Several communities have begun restricting water use in homes and businesses, and water deliveries to California farmers have been curtailed.
While an El Niño is unlikely to bring an end to the drought, Johnson said this doesn't mean California won't see rain, as there are many factors shaping the weather.