Don't Get Too Excited About That Giant El Niño

"While it does point us in a direction, it doesn't promise anything."

Excitement has been building for the massive El Niño heading toward the drought-stricken western U.S., but scientists say the hype is premature. 

The National Oceanic and Atmospheric Administration said it expects this year's El Niño, a periodic warming event in the Pacific Ocean known for dumping rainfall in California and other parts of the West, to be one of the three strongest on record. That makes a wet winter likely -- but not a sure thing.  

"While it does point us in a direction, it doesn’t promise anything," Mike Halpert, the deputy director of the Climate Prediction Center, said in a phone call with reporters Thursday. "We’ve done our best, from NOAA’s point of view, to try to stick to what we understand and what we can say and really stay out of the hype that 'This is the strongest El Niño and this is what it means.'"

If El Niño brings a wet winter, its effects might not be felt strongly outside Southern California. 

"While a strong El Niño signal helps reduce the uncertainty around [California's high weather] variability, making the wet winter more likely in Southern California, it really offers less predictability for a wetter than normal winter in Northern California, a region where it can have the greatest impact in the drought," NOAA hydrologist Alan Haynes said. "Also, remember that El Niño increases the chances for drier and warmer weather in the Pacific Northwest, where drought has started to develop."

The California Department of Water Resources also has played down the El Niño, urging people to look at its effects historically. 

"Six strong El Niño events since 1950 produced wet conditions in Southern California, but only the strongest ones in water years 1983 and 1998 brought significant precipitation throughout the state," a press release from the department noted. "In the four other strong El Niño years, the critical up-state water-collecting regions received far less rainfall. As Water Year 2015 draws to a close, it is still too soon to know whether the building El Niño will be a drought-buster or simply a bust."

One thing the scientists said they are sure of is that a single wet season won't relieve dryness in California, which just began a fifth year of relentless drought

"While there’s some hope for optimism in helping with the drought in California, a full recovery is likely to be uneven across the West and it’s also likely to take more than one season of above-normal precipitation," Haynes said. "If the wettest year were to occur, we still wouldn’t erase the deficit that’s built up over the last four years."

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