I work for an
oceanographic research organization. Several of our scientists work on understanding and predicting El Nino. We got an alert this past weekend from some of our collaborative scientists. It's too long to post in full, but here's some excerpts:
...a truly prodigious amount of snowfall is likely to occur in the mountains, possibly measured in the tens of feet in the Sierra after it's all said and done.
...Between this Sunday and the following Sunday, I expect categorical statewide rainfall totals in excess of 3-4 inches. That is likely to be a huge underestimate for most areas. Much of NorCal is likely to see 5-10 inches in the lowlands, with 10-20 inches in orographically-favored areas. Most of SoCal will see 3-6 inches at lower elevations, with perhaps triple that amount in favored areas.
...The models are virtually unanimous in "reloading" the powerful jet stream and forming an additional persistent kink 2000-3000 miles to our southwest after next Sunday. This is a truly ominous pattern, because it implies the potential for a strong Pineapple-type connection to develop. Indeed, the 12z GFS now shows copious warm rains falling between days 12 and 16 across the entire state.
...Normally, such as scenario out beyond day seven would be dubious at best. Since the models are in such truly remarkable agreement, however, and because of the extremely high potential impact of such an event, it's worth mentioning now. Since there will be a massive volume of freshly-fallen snow (even at relatively low elevations between 3000-5000 feet), even a moderately warm storm event would cause very serious flooding. This situation will have to monitored closely. Even if the tropical connection does not develop, expected rains in the coming 7-10 days will likely be sufficient to cause flooding in and of themselves (even in spite of dry antecedent conditions).
..In short, the next 2-3 weeks (at least) are likely to be more active across California than any other 2-3 week period in recent memory. The potential exists for a dangerous flood scenario to arise at some point during this interval, especially with the possibility of a heavy rain-on-snow event during late week 2.
In some parts of Southern California, a whole season's worth of rain could fall over the course of 5-10 days. This is likely to be a rather memorable event. Stay tuned.
(Bold emphasis was mine). Get out your ponchos and galoshes.
-Bob
I lived in south Florida for 6 years and Washington (state) for one before moving here to San Diego so this is nothing for me, but it is definitely the most it's rained since I've lived here, and the wind is shaking my house! I volunteer on a whale-watching boat and our trips were cancelled today and likely will be throughout the week. I will hope for everyone that the rains become at least manageable for your trips!!! 
No shutting down in sight for us. 
