[env-trinity] Sac Bee 1 8 10

[Byron Leydecker]

El Niño may still give us a wet winter, weather experts say

Sacramento Bee-1/8/10

By Matt Weiser

 

El Niño was predicted to dominate the weather this winter, but a look out
the window suggests that forecast has fizzled.

 

Sacramento rainfall so far this winter is merely normal, and the Sierra
Nevada snowpack is only 84 percent of average.

 

But don't give up on El Niño just yet. 

 

Several weather experts predict El Niño will soon crank open the faucet and
blow away the cold, gray skies that have gripped the Sacramento region for
weeks. They expect much wetter weather through March.

 

"I'm not wringing my hands terribly much," said Tim Barnett, a climate
researcher at the Scripps Institution of Oceanography in San Diego.

 

"Odds are good to see some pretty good storms later in the winter," he said.
"How much rain, nobody can really tell you. All I can tell you is, it will
be in the upper third of all the wet years."

 

John Monteverdi, a professor of meteorology at San Francisco State
University, said he expects El Niño to begin showing its hand in California
next week.

 

"There are lots of indications that a pattern shift is about to occur," he
said.

 

A crucial point is that El Niño typically doesn't deliver its punch until
later in the winter. So it's too early to fear a fourth drought year.

 

"I don't expect a whopper," said Maury Roos, a hydrologist at the California
Department of Water Resources. However, he added, "I'm optimistic we will
wind up getting a fairly decent January and February, probably above
average."

 

El Niño is defined as a warming of the equatorial Pacific Ocean that's
typically in place around Christmas – hence the name, which is Spanish slang
for "Christ child."

 

This warming of the vast Pacific typically alters weather patterns
throughout the Western Hemisphere. In the United States, the Northwest
usually gets drier and the Southwest wetter.

 

Sacramento and Central California, however, sit between these effects, so El
Niño effects here can go either way. The Sierra Nevada snowpack –
all-important to the state's water supplies – is also hard to predict in an
El Niño winter.

 

Yet El Niño is often overhyped in the media because it has, on occasion,
brought memorable and sometimes damaging storms to California.

 

"There is no doubt that we're having an El Niño," said Bill Patzert, a
climatologist at the NASA Jet Propulsion Laboratory in Pasadena. "Now, that
doesn't mean it's going to rain. The impact of the El Niño has often been
exaggerated."

 

Patzert doubts this year's El Niño will bring major rains. He said its
effect is muted by another phenomenon called the Pacific Decadal
Oscillation, a longer-term change that is actually trending toward cooler
ocean temperatures.

 

This winter is considered a moderate El Niño, meaning the ocean warming
isn't as great as the historical maximum. This makes rainfall predictions
even more difficult.

 

In an updated forecast released Thursday, the National Weather Service said
El Niño strengthened in December. The service still predicts improved odds
for above-average precipitation through Jan. 20, especially for Central
California, and continuing through March.

 

In the near term, though, expect more fog through Monday, followed by a
chance of rain Tuesday and Wednesday.

 

A more ambitious prediction comes from Gregg Suhler, whose company, Dynamic
Predictables in Columbia, Mo., developed a unique forecasting tool called
ATLAS.

 

Unlike traditional forecasting that relies on climate observations and
historical trends, ATLAS uses thermodynamic principles to tap into recurring
energy cycles that drive global weather.

 

Simply put, Suhler said, there is a certain amount of energy in the
atmosphere that has to be spent every year in the form of storms. If it
isn't – for instance, during a stretch of drought years – that energy
eventually builds up to produce very big storms on a regular cycle.

 

Suhler said that cycle for the Sacramento River basin is about 16 years, and
is starting to come back around again.

 

As a result, Suhler predicts 15 to 20 inches of rain in the Sacramento River
watershed in February. If it comes to pass, this could refill some of the
state's most important reservoirs, from Shasta to Folsom. It also could
cause damaging floods.

 

Normal February rainfall in the city of Sacramento is 2.8 inches.

 

"January and February are looking to be a really wet sucker," Suhler said.
"We want people to know about it."

 

He developed the forecast after DWR expressed an interest. The state didn't
come through with funding, so he shared it with The Bee.

 

The ATLAS computer model has been presented at science conferences but has
not been published in a peer-reviewed science journal yet, Suhler said.

 

Experts in conventional forecasting are skeptical.

 

"Over the last decade, we've had a lot of false alarms about El Niño,"
Patzert said. "As you look back in the historical record, there really
haven't been that many of what I call 'macho El Niños.' "

 

On the other hand, it's worth looking at the winter of 1994-95. It started
out dry. Californians feared that one of the worst droughts in history –
officially recorded from 1987 to 1992 – wasn't really over.

 

Then El Niño caused major floods in many areas of the state in January and
March 1995, including $220 million in damage and 28 deaths.

 

"It turned out to be a heavy year when it was done, but it was a late
bloomer," Roos said.

 

 

Byron Leydecker, JcT

Chair, Friends of Trinity River

PO Box 2327

Mill Valley, CA 94942-2327

415 383 4810 land/fax (call first to fax)

415 519 4810 mobile

 <mailto:bwl3 at comcast.net> bwl3 at comcast.net

 <mailto:bleydecker at stanfordalumni.org> bleydecker at stanfordalumni.org
(secondary)

 <http://fotr.org/> http://www.fotr.org 

 

 

 

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