El Niño stays warm, boosting hopes for wet California winter

The Pacific Ocean along the equator stands a 95 percent chance of staying warm through winter and possibly influencing storms to hit drought-damaged California, federal officials said Thursday at an increasingly popular monthly update on El Niño.

But National Oceanic and Atmosphere Administration officials and others continued to stress that the drought probably won’t be eliminated in California or the West, even if there is a big rain and snow season.

“A single year of precipitation is unlikely to erase four years of drought in California,” said Kevin Werner, director of NOAA’s Western region climate services. “And it’s entirely possible to see continued drought in parts of the West.”

Since El Niño ocean warming appeared in March, scientists have been trying to temper enthusiasm. California’s climatologist Mike Anderson took it a step further, warning that nobody knows what the winter will bring.

“This uncertainty means that Californians should continue to use water carefully and sparingly in the face of the ongoing extreme drought,” he said.

But there is reason to be cautiously optimistic, scientists said. NOAA officials again confirmed the ocean warmth right now is among the three warmest episodes on record at this time of year, behind 1997 and 1987. The 1987 temperatures fizzled by the time winter arrived, so it was not considered a major event.

El Niño’s influence grows as the ocean temperature rises. The warmest temperatures – above average by 2 degrees Celsius or 3.5 to 4 degrees Fahrenheit – have coincided with monster rain and snow totals in California.

There have only been two super El Niños dating back more than six decades. They happened in the 1997-98 and 1982-83 seasons. California got well beyond 150 percent of average rain and snow.

So far, the event this year is in that category, NOAA officials said. That means California could get a monster season again.

But NOAA explained that it would take 2.5 to 3 times above average rain and snow to make up for drought in California. So even an extraordinary year of precipitation probably would not be enough.

“In 1983, California got about 1.9 times the average,” said Werner.

The most powerful El Niños usually focus storms and rainfall on Southern California, scientists said. The ocean warming is not strongly associated with increased rain and snow in Northern California and the Pacific Northwest, officials said.

The San Joaquin Valley and the rest of Central California might be a little more likely to have increased precipitation because they are farther south, scientists said.

The powerful 1997-98 El Niño season ended with 20.16 inches in Fresno, which averages about 11.5 inches of rain each year. The city’s rainfall set a seasonal record in the 1982-83 El Niño season with 23.57 inches.

But scientists always hedge their bets, saying nothing is certain for specific areas because global weather is affected by many influences.

“It’s far more complicated than just El Niño,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center. “Nothing is guaranteed.”

This story was originally published September 10, 2015 at 2:11 PM with the headline "El Niño stays warm, boosting hopes for wet California winter."