EL ANTICIPATION
The latest El Nino forecast has arrived and it continues to increase in strength. It hit the “strong” level in August for the first time. A key factor will be when it peaks. It not showing any sign of peaking yet, but is apparently forecast to max out in the December timeframe. If it peaks too early, it will not have the impact on our winter weather that we are hoping and praying for.
Despite what you may have heard from other forecasters, there have only been FOUR strong El Ninos since 1950. To clarify: four strong El Ninos “in the winter”; three of these had above average rain in California in the winter, and the fourth had “slightly above average” rain. Let me explain: The four strong El Ninos were: 1998, 1983, 1958, and 1973. As we all probably know, the first three had well above average precipitation for northern CA in the winter. No question about that. In 1973, however, I see about 103% of average precipitation for northern CA, noting that this strong El Nino peaked early in November (but still remained strong through the winter). Usually, forecasters referring to 1973 say it was an above average year for this strong El Nino, but I don’t think you can say 103% is “above average”, to me it is more “average”, but if you really want to then say “slightly above average”. The Southern Sierra may have been slightly higher that year.
There were two other strong El Ninos since 1950: 1966 and 1988. Both of these years had well below average winters for northern CA. However, it must be noted that both of these El Ninos were on the very low end of strong; the El Nino of 1988 peaked in the summer and was not strong when winter started; the El Nino of 1966 peaked in November/December and by January it was down to moderate strength. That is a very important distinction. Does it rain in the summer in California? No it doesn’t! So in the heart of winter, these strong El Ninos were not strong! Therefore, in my opinion, it is not appropriate to say El Nino was strong in those years if you are talking about predicting precipitation in the winter for California; they were moderate El Ninos during the winter of those years, not strong ones.
The other factor we have is the warm blob of water off the coast. In past strong events, this blob did not exist, and it also could be the reason we are currently in a four year drought. If it was not there, it is quite likely at least 2 of the 4 years we would have had average or above average precipitation. So will it affect the strong El Nino, and how? No one knows of course; personally I think it likely it will have some sort of negative effect, but the question is how much.
If we do have a big winter, I will be extremely excited of course. I was not living in California during the last big El Nino. I moved down here in 1999. I am already trying to map out where I will be hiking and what waterfalls I will be visiting this winter. Are you making your list yet? Pictured here is the Lower Middle Fork Tuolumne River Falls, 182 ft. high. Is this going to one of the waterfalls I will be visiting? Perhaps it will, though it is not specifically on my list (but nonetheless, I will be visiting this area for sure next year). If you have not seen it yet yourself, then you will certainly want to put it on your list. It is going to be amazing next year at high flows.