Sacramento is in the peak of its rainy season, but there is no substantial rain in the forecast for the next two weeks. The Sierra snowpack has fallen below normal levels for this time of year. The state’s three largest reservoirs remain far below capacity.
Whither El Niño?
Throughout the summer and fall of 2015, California residents waited in anticipation as they heard about the strong El Niño weather pattern brewing in the Pacific Ocean. We remembered the winters of 1997-98 and 1982-83, when such strong El Niños corresponded with deluges. And we hoped for relief from our long, brutal drought.
But through Feb. 20, Sacramento has seen half the precipitation that occurred by this point in 1997-98 and 1982-83.
Bill Patzert, climate expert at NASA's Jet Propulsion Laboratory in Pasadena, said a dry February doesn’t mean El Niño has run its course, however. In the 1983 El Niño winter, “the big show really didn’t happen until March and April. I’m still holding out hope.”
Patzert said the timing of the precipitation varies with the intensity of the El Niño pattern, which is a function of warmer-than-usual water temperatures in the Pacific Ocean. In 1998, the water temperatures peaked in November and much of the rain fell in February. In 1983, it peaked in January - as it did this year - and the bulk of the rain came in March and April.
Jan Null, former National Weather Service forecaster, now a private consultant with Golden Gate Weather Services in Saratoga, also isn't quite ready to label this El Niño a dud.
“It’s possible there’s another shoe to drop. There is still a lot of warm water out in the Pacific,” Null said. Water temperatures are still considerably warmer than normal.
But during the next seven days, the only rain in the forecast is a mild system arriving Friday night that likely will bring less than one-tenth of an inch of precipitation to Sacramento.
The 8-14 day outlook from the federal Climate Prediction Center also is discouraging. It predicts a strong chance of below-average precipitation throughout California for March 3-8.
Null said this year’s winter is yet another example that El Niños are unpredictable and any long-range weather forecast is suspect. The nexus of warm water in the Pacific is further west than usual this year. That is a big factor in determining where the rain will fall. Often El Niño brings heavy rain to Southern California; this year it’s been rainier in Northern California, and portions of the Pacific Northwest have gotten record precipitation.
It’s not clear why the warm water is so far west this year, and it’s not clear why that’s creating such unusual weather patterns.
“We don’t know all the answers," Null said. "This has sort of become the poster child that all El Niños are different.”
Even if the rains return with a vengeance, Patzert doesn’t expect El Niño to end the drought.
“Everybody expected this El Niño to be the great...drought-buster, but that was never going to happen. It took us 15 years to get into this drought. No matter how successful the rainfall might (be) in February and March, we were still going to be in a drought when it was all over...Lake Mead has never been this low before. Lake Oroville and Lake Shasta are not going to fill up no matter what.”