Weather Watch

When will the drought end? Predictions are all over the map

Special to The TribuneOctober 26, 2013 

Sea lions and birds at Lion Rock near Diablo Canyon. Without rainfall to wash away bird guano, the air is pungent with their odor.

JOHN LINDSEY

So far, 2013 is now the driest year on record at Cal Poly since 1870 when weather observations started.

The second driest January-to-October on record at Cal Poly occurred in 1972, when 5.5 inches of rain fell. The next driest was 1984, when 4.3 inches of precipitation were recorded. So far this year, only a meager 3.5 inches of rain has fallen.

Rain showers are expected this Monday and Tuesday, but rainfall amounts are expected to remain below half an inch.

The effects of this extreme drought can be seen throughout San Luis Obispo County as our rolling hills continue to turn from hues of golden brown to shades of gray. It’s affecting all of us.

Robert Lewin, Cal Fire chief for San Luis Obispo County, said, "Until we get a couple of inches of rain and a forecast for more, we are going to be forced to continue staffing all of our fire season engines, dozers, crews and aircraft. This is going to strain our budget."

At Old Creek Ranch near Cayucos, Bob Blanchard, who has raised cattle along the Central Coast since the 1950s, said “This year’s dry spell is the most severe I have seen. Cattle ranchers along the coastal sections of San Luis Obispo County are eagerly anticipating the green-up that winter rains will bring. The majority of the ranchers east of Highway 101 have either sold or moved their cattle to other locations.”

Not only can you see the drought, you can smell it. If you have visited beaches where offshore rock or island monuments provide refuge for marine mammals and birds, you know the smell of guano has increased.

Lion Rock is a relatively large island that rises about 100 feet above sea level near Diablo Canyon Power Plant. It is home to hundreds of California Sea Lions and numerous cormorants and pelicans that flourish there. The pungent smell from this island has gotten worse without the October rains to wash it off.

North of the Cuesta Grade, Lake San Antonio is at 5 percent capacity, with its water elevation at 656 feet. The dead pool elevation of the lake is 645 feet. When the lake is at that level, water cannot be released via gravity flow. This is the all-time low water elevation at the lake.

On the other hand, Nacimiento Lake is currently at 26 percent of capacity with its water elevation at 732 feet. The dead pool elevation at this lake is 670 feet. In October of 2009, the lake was only at 9 percent capacity with a level of 700 feet.

So what does the 2014 rain season (July 1, 2013, through June 30, 2014) hold in store for us?

This year, conditions don’t exist for either an El Niño or its sister, La Niña. The U.S. Climate Prediction Center is predicting that the neutral conditions — the infamous El Nothing or El Nada — will continue through winter.

Neutral conditions generally don’t produce any reliable seasonal rainfall predictions along the Central Coast.

However, there is another ocean water temperature cycle that seems to be playing a larger role. It’s called the Pacific Decadal Oscillation, or PDO, and it probably has the same effect on our rainfall as El Niño and La Niña in San Luis Obispo County.

The phases of the PDO are called warm or cool phases. There’s a growing amount of evidence that the warm phase of the PDO produces above-normal levels of rainfall, while the cool phase produces below-normal levels.

According to Dr. Josh Willis of the NASA Jet Propulsion Laboratory (JPL) in Pasadena, “There is some research to suggest that during negative phases of the PDO, La Niñas become more frequent and El Niños become less so.”

Unfortunately, we’re still in the cool phase of the PDO, meaning we could continue to see below-average rainfall. Nevertheless, the current seawater trends seem to indicate that we could move into the warm phase of the PDO by early next year.

It’s interesting to note that the Farmer’s Almanac is advertising near normal rain amounts for California this winter.

TheWeatherSpace.com web site is predicting extreme above normal rainfall in February.

However, JPL oceanographer Dr. Bill Patzert who studies the ocean's role in climate is calling for below average rainfall this winter.

My prediction for this rain season: between 15 and 20 inches as measured at Cal Poly.

John Lindsey's column is special to The Tribune. He is a media relations representative for PG&E and a longtime local meteorologist. He is president of the Point San Luis Lighthouse Keepers. If you have a question, send him an email at pgeweather@pge.com.

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