Though chances remain fairly high that the strengthening El Niño will mean a lot of wetness (and possible flooding) for the Bay Area, there is a chance the majority of the rain will go to Southern California. And one major complicating factor for this El Niño, distinct from other strong ones like '97-'98, is that damn blob.
The warm water blob in the Pacific off the California coast is unrelated to the El Niño pattern, or to El Niño-related warming in the ocean, and it started taking shape two years ago. As Oregon Live reports, it has likely been the culprit in some bizarre happenings across all levels of the food chain off our coast, and is making for a "double whammy" with the El Niño taking shape that is causing forecasters to throw all known models out the window. The blob, and or El Niño, has meant a boon for Bay Area fishermen as well, with salmon and rock cod chasing schools of anchovies and other tiny fish that have moved into our warmer coastal waters.
As the Chronicle reports today, historical precedent for strong El Niños tells us that the northern half of California should get a lot of rain. However this year it could be tempered by the blob, which some climatologists have blamed for our last two extra-dry winters. And Stanford University climate researcher Daniel Swain explains that while rain for SoCal is a guarantee, "The average El Niño signal is not really meaningful for [all of] California.”
The weather people will be giving the next update on El Niño in two weeks.