SACRAMENTO — El Nino may be bringing a wet winter, but October is gearing up to be mostly dry throughout California’s Central Valley.
The National Weather Service was growing confident that a weather system would arrive by Oct. 4, bringing cooler temperatures and mountain precipitation that could spread into the valley.
But beyond that, long-range forecasts from AccuWeather envision mostly sunny days with afternoon highs in the 70s and 80s through Halloween, with a few cloudy days and perhaps a stray drizzle sprinkled in.
“Right now we’re in a transition period, so it’s really tough to say if it’s a trend,” said Nathan Owen, a National Weather Service meteorologist in Sacramento. “We’re kind of on a roller-coaster.”
The outlook comes as California was set to begin a new water year on Oct. 1, closing the books on a fourth straight year of drought and hoping to not suffer through a fifth. Most areas finished the 2014-2015 water year with much less precipitation than normal and averaging warmer-than-normal temperatures, notes the state Department of Water Resources.
For instance, Redding finished the water year with 23.63 inches of rainfall — well below the 34.56 inches it normally receives, according to the National Weather Service. Fresno measured a meager 6.97 inches of precipitation for the year, far below its normal 11.48 inches.
The low rainfall totals and nearly nonexistent snowpack caused California’s major reservoirs to start the fall with well-below-normal storage. Those include Shasta Lake (59 percent of normal for this time of year), Lake Oroville (49 percent), Trinity Lake (33 percent), Folsom Lake (32 percent) and New Melones Reservoir (20 percent), the DWR notes.
Federal forecasters said recently they are now confident that a strong El Nino will boost rainfall in parts of California this winter — perhaps as far north as Sacramento. They said there’s a 95 percent chance that El Nino conditions will persist until next spring.
However, the federal Climate Prediction Center’s most recent three-month outlook foresees higher-than-average precipitation in Southern California only, with equal chances of above- or below-average precipitation for the middle of the state. Far Northern California and the Pacific Northwest figure to be drier than normal, according to the outlook.
The big question for scientists is whether the developing El Nino will be strong enough to displace “the blob,” another mass of warm water in the northern Pacific that set up the stubborn high-pressure ridge that has diverted storms away from California and caused the four-year drought.
The ridge was still holding as of last week, as temperatures throughout the state averaged nearly 10 degrees above normal, federal officials reported.
A relatively dry October would help growers finish their harvests, which are ongoing for rice and other field crops as well as olives and wine grapes and just starting for walnuts and persimmons, according to the National Agricultural Statistics Service.