OK, So Where Is This El Niño Already?

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What remains of Folsom Lake, as it continues to sink to record low levels.  (Dan Brekke/KQED)

If you're a drought pessimist, or just the nervous type, you might see California's weather so far this fall as a confirmation of your worst fears. Forecasters far and wide assure us that we are on the threshold of an epically wet, El Niño-fueled winter. And they've got the data and the models to back up that outlook.

What they don't have so far is actual rain or (much) snow to calm the skeptics among us. What we see is shrinking reservoirs, below-normal precipitation in many locations and the memory of the past several "rainy" seasons in which anomalously dry, warm winter weather has prevailed (we're looking at you, Ridiculously Resilient Ridge.)

For the truly determined drought-relief doubter, Exhibit A has got to be last winter.

The 'long-lead seasonal outlook'; from NOAA's Climate Prediction Center, issued in mid-December 2014, indicated that models pointed to above-median precipitation in California in early 2015. The period turned out to be among the state's driest on record.
The 'long-lead seasonal outlook' from NOAA's Climate Prediction Center, issued in mid-December 2014, indicated that models pointed to above-median precipitation in California in early 2015. Instead, the period was among the state's driest on record. (NOAA-Climate Prediction Center)

It began with a sopping-wet December. With the benefit of hindsight and the archives of National Oceanic and Atmospheric Administration's Climate Prediction Center, we can go back to the middle of that rainy month and revisit what the dynamical forecast models were telling weather scientists and hopeful lay people about the coming months.

Yes, it looked like the chances were good for a moist January, February and March. What happened instead, of course, is that the storms that had dumped trillions of gallons of water on the state vanished. Most of California experienced its driest January on record.


So why, one may ask as we watch Folsom Lake hit its record low and see every one of the state's biggest reservoirs sink to 30 percent of capacity or less, should anyone expect the long-term outlooks will be right this time?

Daniel Swain, the Stanford meteorological researcher and climate blogger, noted last week that the dynamical models have already scored one coup by correctly forecasting the "implausibly high" sea surface temperatures now being seen in the central equatorial Pacific. That lends credence to the models' forecast of a wet, and possibly wild, winter.

"In fact, it’s hard to envision a set of mid-November observations and model output that would lead to higher confidence in a wetter-than-average California winter than the ones currently in place," Swain wrote.

We don't pretend to actual meteorological sophistication, so what the forecasters say is likely to happen may well come to pass. Still, until we see the storms lined up across the Pacific, we'll be imagining what California will look like if the models go bust again.

To close, here are stats for a few of California's key reservoirs and where they stand now, compared with their all-time lows.

Reservoir Capacity
Pre-2015 low Date Current level
Shasta 4.5 million 562,600 Sept. 13, 1977 1,351,081
Oroville 3.55 million 882,395 Sept. 7, 1977 946,422
Trinity 2.45 million 222,350 Nov. 9, 1977 485,615
New Melones 2.4 million 86,631 Oct. 1, 1992 265,455
San Luis 2 million 201,049 Nov. 7, 1977 409,303
Folsom 977,000 140,600 Nov. 20-21, 1977 138,775

Data sources: California Department of Water Resources, U.S. Geological Survey.