The National Weather Service now expects El Niño to bring greater-than-average rainfall to virtually all of California, forecasters said for the first time Thursday.
The new forecast is significant because it raises the chance that El Niño will send big storms not only to Southern California and the San Francisco Bay Area — as has already been forecast — but also to the mountains that feed California’s most important reservoirs, which fuel water for much of the entire state. California’s largest reservoirs, Shasta Lake and Lake Oroville, are in the northern edge of the state.
If patterns from previous strong El Niños repeat, “there will be a number of significant storms that will bring heavy rains. What that brings will be floods and mudslides,” said Mike Halpert, deputy director of the National Weather Service’s Climate Prediction Center. “We’re more confident we’re going to be seeing El Niño through this winter.”
Federal officials said they expect El Niño rains to ease drought conditions in California, but they're not expected to eliminate the drought because the state is so far behind on precipitation.
The chance of heavy rain is strongest in Los Angeles and San Diego, where there is a 60% chance of a wet winter, a 33% chance of an average winter and less than a 7% chance of a dry winter.
In Silicon Valley, there is more than a 50% likelihood of a wet winter and less than a 17% chance of a dry winter. Farther north, there is a greater than 40% chance of a wetter-than-average rainy winter in San Francisco and Sacramento, and less than a 27% probability of a drier-than-normal winter.
With the latest prediction, the far northern parts of California — now reaching the border with Oregon — are expected to have a 33% to 39% chance of a wetter-than-average winter, and a 28% to 33% chance of a dry one. Last month, the climate forecast for that area was only equal chances of a wet or dry winter.
The latest winter climate forecast for the January-February-March time frame comes as El Niño is still very strong in the Pacific Ocean west of Peru. El Niño is a weather phenomenon that involves warming sea-surface temperatures and a change in wind that alters weather patterns in the atmosphere worldwide.
A powerful El Niño can move the jet stream that funnels wet winter storms over the jungles of southern Mexico and Central America north, dousing California and the southern United States with dramatic, punishing and potentially deadly winter rain.
Halpert said the power of the upcoming El Niño likely will be comparable to the 1982-83 and the 1997-98 El Niños. Those winters brought dramatic weather changes worldwide and extensive damage and flooding throughout California.Read more...
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