Thursday, January 8, 2015

El Nino Sputters; Bad News For California Drought?

Rain storms hit California in December, denting
the drought, but now storms, and an El Nino
weather pattern the was supposed to bring more
rain, is faltering. Image from KTLA.  
A pretty substantial El Nino pattern in the Pacific Ocean was supposed to be getting under way right now.

An El Nino is a ocean temperature pattern in the Pacific Ocean that brings warmer water to near the west coast of South America, and includes other changes in the ocean temperature.

El Ninos also affect worldwide weather patterns. One of the things El Ninos often do is bring lots of rainy storms to California in the winter.

Despite the risk of flooding from the heaviest storms, California, at least lately, has been looking forward to the El Nino to diminish a punishing drought in the state.

Things were looking up. A weak El Nino seemed to be developing. A couple large storms slammed into California. Those caused some damaging floods and mudslide, yes, because the rain came down too hard, too fast in some areas.

But at least the storms dented the drought. And if the rains continued all winter, by spring, there wouldn't be such a drought emergency in California. So everyone hoped, anyway.

Now, it seems, El Nino is sputtering, as Dr. Jeff Masters notes in his Weather Underground blog.

El Nino conditions are weak, and the people who predict such things are now no longer as bullish as they were that El Nino would continue for awhile.

I'll let Masters explain it, in this excerpt from his blog post:

"Although the tropical Pacific waters behaved as if a major El Nino was on tap, it seems the atmosphere didn't get the message. Throughout 2014, the atmospheric component of El Nino failed to emerge consistently even as oceanic conditions appeared favorable. 

For example, a developing El Nino typically sees trade winds weakening across the eastern Pacific, which facilitates the eastward spread of warm surface water. Although several bursts of westerly wind did appear in 2014, these have not translated into widespread, long-lived weakening of the easterly trade winds. Without the linkage that emerges from this kind of ocean-atmosphere interaction, it is difficult for El Nino conditions to take hold in a big way."

Why the atmosphere doesn't seem to be getting its act together for an El Nino is unclear, says Masters.

Other Pacific temperature patterns might have gotten in the way. Or abnormally warm water in the western Pacific Ocean might have disrupted things. Climatologists and other scientists will be studying this, for sure.

Although I can't exactly prove the link between an El Nino that's turning out to be more lame than expected and current California weather, it is interesting that the storminess has shut off in that region in the past couple of weeks.

The amount of snow in the Sierra Nevada mountains is more, and has more water in it, than this time last year, but that's not saying much. Snow levels are still well below normal. 

That's bad news, because California depends a lot on water from Sierra Nevada snowmelt during the spring and summer to supply drinking water to big cities, and to keep agriculture going.

The immediate forecast is mixed at best.  Over the next week or so, only very light rain is expected in parts of California. Above normal temperatures will increase evaporation, and melt some of the scant snow in the Sierras, so that's not good.

Some rain looks like it wants to come into California after mid-month, but those storms certainly don't look like blockbusters.

California's rainy season pretty much ends in April, so time is already starting to run out. January doesn't look like it will turn out to be a big precipitation month in the Golden State.

California has been in a huge drought for three years now. Unless they get epic rains and snows in February and March, the punishing drought will drag on.

By the way, you should care even if you don't live in California. This will have an effect on food prices, and the overall economy if things get too bad.

Do us all a favor and perform a California rain dance, will ya?

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