(CN) - While forecasters remain bullish on the chances of El Nino barraging Los Angeles with rain this winter, the likelihood of the state's reservoirs filling up remains in doubt.
On Thursday, federal forecasters with the National Oceanic and Atmospheric Administration released their much-anticipated winter outlook and predicted above normal rainfall and improved drought conditions through March across Central and Southern California.
NOAA scientists say the best chance for heavy rain is in San Diego and Los Angeles, where they predict a 60 percent chance of above-average rainfall and just a seven percent chance of a dry winter.
But farther north, where the bulk of California's major reservoirs are fed by snowmelt and runoff from the Sierra Nevada, the forecast is far from the drought-buster the state's water savings accounts need as they approach historic lows.
NOAA's winter outlook gives much of Northern California just a 33 percent chance of increased rainfall and the most northern counties an equal chance. Even worse, temperatures this winter are expected to be warmer than average, a likely deterrent for the snow Northern California desperately needs.
Last month, a report published in the journal "Nature Climate Change" estimated the amount of snow in the Sierras was the lowest it had been in more than 500 years. In a normal year, melting Sierra snow provides the state with a third of its water.
While El Nino is almost certain to influence weather patterns in Southern California, forecasters say they aren't sure if, when and where it will snow in Northern California.
"A strong El Niño is in place and should exert a strong influence over our weather this winter," Mike Halpert, deputy director of NOAA's Climate Prediction Center, said in a statement. "Cold-air outbreaks and snow storms will likely occur at times this winter. However, the frequency, number and intensity of these events cannot be predicted on a seasonal timescale."
Snow forecasts are generally unpredictable more than a week out because they depend so heavily on the strength and direction of winter storms which often change their track unexpectedly.
Regardless of the actual strength of El Nino's impact, California will head into a fifth consecutive year of extreme drought in 2016.
"California would need close to twice its normal rainfall to get out of drought and that's unlikely," Halpert said.
The El Nino event of 1997-1998, one of the strongest on record, dumped 32 inches of rain on Sacramento - a city that gets 18 inches in a normal year.
Previews of El Nino's likely destructive impact on California were felt earlier this week when unseasonable thunderstorms struck southern parts of the state, trapping motorists and clogging interstates with massive amounts of mud.
Two major north-south arteries into Los Angeles were closed Thursday and into Friday as flash flooding engulfed large stretches of Interstate 5 and Highway 58 in Los Angeles and Kern counties. I-5 through the Grapevine is expected to open by late Friday, but Highway 58 will remain closed for days as crews remove 20 feet of mud and more than 200 cars from the roadway east of Tehachapi.
Meanwhile in Northern California, officials estimated economic damages of more than $1.5 billion from the Valley fire that destroyed more than 1,900 structures in Lake County last month. The deadly fire burned more than 76,000 acres in Lake, Sonoma and Napa counties and according to officials is the third-most destructive wildfire in the state's history.
On Wednesday, Cal Fire officials declared 133 different locations in recent fire zones throughout Northern California as mudslide danger zones and warned residents to be prepared for highway closures this winter.
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