Yes, this is what a La Niña looks like

Source: NASA. Click on the image for a NASA explanation of the "Pineapple Express," in which a jet stream carries moisture from near Hawaii over the American Southwest.

KQED’s Climate Watch, David Zetland’s Aguanomics, LA Observed and the LA Times are among the websites and news organizations shaking seeming contradictions from their collective umbrellas. Yes, this is a La Niña year, and yes, these are typically drier than normal. This being a far stronger than normal La Niña, chances were strong that it was going to be far drier than the already dry average across the American Southwest.

The short answer to why we’re having such a wet dry year is that we’ve had a rare incursion of a tropical rain system called “the Pineapple Express.” The longer answer might be that it is an indicator of climate change. We are not the only ones experiencing

The Dry Garden: “a strong La Niña”

The blue purple band in the center is a building La Niña in the equatorial Pacific. Source: Jason satellite/JPL. Click on the image to be taken to JPL's El Niño/La Niña compendium of Jason images.

Autumn and early winter are traditionally considered planting season in Southern California because nature can be expected to cooperate. As days shorten and rains come, seeds germinate, newly transplanted saplings deepen their roots and established plants awaken from dormancy.

Yet not all years are created equal, and this coming planting season has all the hallmarks of a tricky one.

National Weather Service predictions for a La Niña cycle are becoming less tentative and more ominous. That means ocean temperature trends in the equatorial Pacific have shifted to the opposite of last winter —  a way that augurs drought.

How dry our rainy season might be is unknowable; this brooding La Niña might even produce a

The Dry Garden: Wet policy for a dry year

Source: NOAA. Click on the maps to be taken to composite graphics of precipitation trends during La Niña years.

We’ve been getting mixed messages about whether or not we need to conserve water. On one hand, we had a decent local rain year. Last week, the state legislature pulled a water bond from the November ballot that would have driven state-wide conservation. This week, the Los Angeles City Council amended the two-day lawn sprinkler ordinance to a three-day version.

Crisis over?

Not by a long shot. Local rain doesn’t fill our pipes. Of the three main sources that do, Lake Mead, the Colorado River storage reservoir serving Southern California, shrank in July to its lowest level since 1956. Last month, the State Water Resources Control Board concluded that the Sacramento-San Joaquin Delta is overdrawn by 50%. Southern California could do its part to fix that by reducing water use from

La Niña watch begins

After 16.36* inches of rain recorded for downtown Los Angeles from June 2009-June 2010, ocean conditions indicate a transition from the mildly wet El Niño system that gave Southern California a slightly better than average rainfall year to a dry La Niña one, according to the National Weather Service. An experimental and unofficial outlook map set issued by its Climate Prediction Center lays out a hot and dry 2010/11. Jet Propulsion Laboratory oceanographer Bill Patzert is already betting on a dry La Niña 2010/11 season. “Two years of El Niño are just such a low probability,” he said. “Six out of ten years are dry. I wish I had those odds in Vegas.” For those who think in terms of “normal” rainfall for Los Angeles, he added, “Normal is a cycle on a washing machine.”

*From the NWS California Nevada Forecast Center. NWS Los Angeles / Oxnard records …

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