The areas that need strong El Niño storms the most are likely to get them, forecasters said Thursday.

  The U.S. Climate Prediction Center, in its monthly long-term weather outlook, boosted the odds of precipitation for California this winter and spring — including, crucially, the areas in the North State and Sierra that supply the bulk of the state’s water supply.

  Forecasters have long pegged Southern and Central California for rain in coming months, but with El Niño in the tropical Pacific gaining strength and warm pockets of ocean water expected to add moisture to the atmosphere, federal forecasters have broadened their bullishness.

  The updated outlook calls for at least 40 percent above-average chances of wet weather between January and March for nearly the entire state, including all of the Sierra Nevada. San Francisco stands a more than 40 percent above-average chance of seeing a rainy winter, according to the federal forecasters, while the South Bay has 50 percent greater odds.

  This El Niño, defined by warm equatorial waters that drive moisture into the atmosphere, is one of the strongest that forecasters have observed. Temperatures in the tropics are much greater than normal, and trade winds that typically push warm currents away from the Americas have died.


http://www.sfgate.com/bayarea/article/El-Ni-o-looking-like-a-rainy-winner-for-6572344.php