UPDATE: North Bay Water Supply, El Nino Outlooks

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As we enter the rainy season the North Bay and most of California has a lot of water in storage, a big contrast to recent years. In fact, the state’s reservoirs are nearly all running above historical averages (green percentage) for this time of year.

Lake Sonoma, which supplies around 600 thousand North Bay customers, is at 113% of historical average.

For our current water year, we in the North Bay have received about 50-70 percent of historical average rainfall, including the 2-3 inches we picked up from the most recent storm. It is still very early in the rainy season.

At the same time, sea surface temperatures continue to heat up in the equatorial Pacific, and have now passed the threshold of a so called “Super El Nino, which is 2 degrees celsius or more above average in the Nino 3.4 zone, (the place in the ocean where measurements are taken for comparison).

To be officially classified as a Super El Nino, those anomalously high temperatures will need to continue for at least three months. This seems likely as most forecasts call for the El Nino to peak in December or January.

For Central California and the North Bay, past very strong El Ninos have brought wet winters of around 110-140 percent of average rainfall. Already we’re seeing things heat up in the long range forecasts, which generally agree on a broad low pressure trough setting up off the coast of California, with storms beginning in the first week of December.