First let's talk about the significance of El Nino; El Nino winters almost certainly are average to significantly above average for the Sierra Nevada mountains around Lake Tahoe. After last winter (or lack thereof), El Nino would be a welcome site. El Nino is warming surface temperatures in the Equatorial Pacific waters. Forecasters who want an early jump on how the winter will shape up usually start with the ENSO (El Nino Southern Oscillation). Currently we are in a neutral ENSO. I believe that is changing as I write this. There are many indicators that things are radically different than last year ... some scientific (like ocean temperatures) and some not so scientific. Last year I mentioned that many forecasters saw wet early winter for our area. I did not climb on that bandwagon. We moved into a strong La Nina early on and that more times than not means below average precip. The previous winter meant that La Nina brought giant storms and well above average precip ... so many saw the strengthening La Nina as a sign of early winter and more of the same. Wrong.
The models are all over the place as to when El Nino arrives. However most forecasters agree that the dynamical model is correct. That model says El Nino starts between now and September. I believe that this is the case and looking around (2 days of rain in July, storms making to Tahoe) I think we are seeing the effects of El Nino already.
What does this mean? We are going to have winter this year. Our storms will not be as large, but they may arrive on the heels of a previous storm. Winter should be early, although that is tough predictor. I believe we will have above average precip this winter with a chance of significantly above average precip.
Disclaimer: This machine that God created is complex and nobody even comes close to understanding it. Remember a decent storm will pick up 10,000,000,000,000 gallons of water from the Pacific, desalinate it, and dump in the Sierra in 1 day. Giant desalination plants cannot do that in 100 years. If we remember that we have little to no control over our weather we will realize that what we are saying is nothing more than guess work. I am hoping in this case ... educated guesswork.
Stay Tuned ...