As a hydrologist I am steeped in models based on past observations and predictions based on analogous years, etc. But climate change is forcing us to rethink our projections and those p values. My point is that while we have data and statistical methods Sir Gilbert Walker could not have dreamt of, we are also faced with trends our models, fancy as they are, would not have predicted a short 30 years ago. We don't have to look far to see manifestations of this - this winter's intrusions of the polar vortex deep into the central U.S., or the ongoing convective storm destruction wrought by converging air masses over mid-America. The jet stream is becoming both weaker and less organized. In large measure it was that weakness that brought us the polar vortex and those lingering storms and it is observed past tendencies of storm tracks driven by jet stream patterns that suggests that this el Nino will bring storms to southern CA. Bringing this uncertainty to the question of rainfall this winter in the Central Valley - leads to my favorite answer to the question - what to expect from perturbations of complex systems - surprise. I'm not suggesting your answer is wrong - there certainly is hope based on past experience - but I sure as hell would not bet the farm on it.