Weather Watch

El Niño came, so why didn’t it bring more rain?

Differences between the 1998 and 2016 El Niño events during the month of April. This April, a large area of the northeastern tropical Pacific still contains a large area of warmer than normal heat content. The El Nino footprint is still strong. These 1997-1998 and 2015-2016 El Niño animations were made from data collected by the TOPEX/Poseidon (1997-1998) and the OSTM/Jason-2 (2015-2016) satellites.
Differences between the 1998 and 2016 El Niño events during the month of April. This April, a large area of the northeastern tropical Pacific still contains a large area of warmer than normal heat content. The El Nino footprint is still strong. These 1997-1998 and 2015-2016 El Niño animations were made from data collected by the TOPEX/Poseidon (1997-1998) and the OSTM/Jason-2 (2015-2016) satellites.

Loren Eiseley, the great humanist and naturalist, wrote, “If there is magic on the planet, it is contained in water. ... Its substance reaches everywhere; it touches the past and prepares the future; it moves under the poles and wanders thinly in the heights of air.”

Eiseley’s beautiful essay is correct on many levels. Water vapor in our atmosphere condenses into precipitation and releases latent heat that can have profound implications for severe weather in California. The warmer the atmosphere, the more water vapor it can hold. The temperature of the seawater in the equatorial Pacific as it cycles between El Niño and La Niña events can even have greater impacts on the Golden State.

William Patzert, a respected climatologist with Caltech’s NASA Jet Propulsion Laboratory in Pasadena, told me, “This El Niño event was the strongest on record. It lasted longer (didn’t peak until January 2016), covered a larger area and is still present. Remember that 2014-15 was a weak El Niño, so this one had a jump-start. It was really a continuing El Niño.”

“Unfortunately, its effects weren’t as great as previous champ, the 1997-98 El Niño. That cycle produced huge amounts of rain and snow. This year’s El Niño was no Godzilla, more of a gecko as far as impacts were concerned.”

This leads to the question of why this year’s record-breaking El Niño event produced well below expected precipitation. The last two very strong El Niño events (1982-83 and 1997-98) produced about 200 percent of average rainfall along the Central Coast. The answer is probably climate change.

I’ve been forecasting weather along the Central Coast since the 1990s and seen both the ocean and atmosphere become warmer. I’ve calibrated, downloaded and archived seawater temperature recorder data from monitoring stations along the Pecho Coast — the coastal stretch between Point San Luis Lighthouse and Point Buchon just south of Montaña de Oro State Park.

These seawater temperature monitoring stations continued to show an upsurge in ocean temperatures. Atmospheric data from the airports in San Luis Obispo, Paso Robles and Santa Maria continue to show a marked increase in air temperatures since the 1950s. Globally, NASA, the National Oceanic and Atmospheric Administration and the World Meteorological Organization all announced that 2015 was the hottest year on record, shattering the previous record set in 2014 by more than one-tenth of a degree Celsius. Now 2016 is on pace to break the 2015 record!

Many renowned climatologists believe that these warmer temperatures are contributing to the persistent high pressure over the West Coast, nicknamed the “Ridiculously Resilient Ridge,” that has directed many storms to the north and the possible atmospheric rivers they could bring. For our area, just one or two “Pineapple Expresses” bringing moist air from the tropical Pacific is the difference between a dry and wet year.

“Here in California, the ‘great drought’ of the past decade and a half reminds us of the value of our water,” Patzert said. “The natural ebbs and flows of the climate system have always modulated water supplies and controlled the waxing and waning of civilizations in the American West. But today the rules have changed. Man-made climate change is warming and drying the West. Yes, the American West, as well as much of the Middle East, India, China, and many other regions, is headed for a water crisis. Concerns about the world’s freshwater supplies are accelerating.”

At this time, the latest guidance from the Climate Prediction Center indicates that La Niña (colder than normal ocean water in the equatorial and eastern Pacific) pattern may develop later this year. This condition often shifts the storm track further northward into the Pacific Northwest, producing below-average rainfall along the Central Coast. The long-range climate models continue to indicate that droughts in California will become more severe in the future. So far, they’ve been verifying.

Admiral David Titley, former oceanographer and navigator of the Navy, is now a professor at Pennsylvania State University and founding director of Penn State’s Center for Solutions to Weather and Climate Risk. Titley has always stressed that climate change is fundamentally a risk management issue — and as we learn more about it, we often find out that the risks are greater, not less than what we originally thought. As time marches on, climate change will be the defining challenge for all of us, especially for our children.

If you happen to be a climate change skeptic, please visit Dr. Ray Weymann’s website at www.centralcoastclimatescience.org. It’s a reliable and timely site.

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John Lindsey’s column is special to The Tribune. He is the PG&E Diablo Canyon meteorologist and media relations representative. Email him at pgeweather@pge.com

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