It's not likely that the ridges that have minimized preciptiation over Southern California are related to global warming.  This pattern has certainly been less prevalent than the last few winters, but for reasons not yet understood, the majority of storminess that impacted the west coast this winter was mianly from northern California northward into the Pacific NW.  While not what we had seen during the 1997/98 or 1982/83 El Ninos, that's a very small sample size to be drawing huge inferences, and other climate patterns (the Arctic Oscilation, the Madden-Julian Oscillation, maybe others) also played a role in determining the patterns of rainfall along the West Coast this past winter.