El Niño strengthening and what that means for us in Southern California

2015_El Nino Strength

The latest El Niño forecast is in and it is looking more and more likely that we are in for a very strong El Niño through the winter of 2015-16.  There is even a 60% chance that we could experience the strongest El Niño in modern times.  So what does this mean for California and especially our drought?  Keep reading and I’ll try and answer this question.

ElNino_Forecast

The above image is the latest forecast for El Niño.  This shows the different models and what they are projecting.  As you can see, almost all of them are forecasting a strong El Niño with some even above the record El Niño of 1997.

2015_El Nino Rainfall

Of course the big question is: Will we get enough rain in the winter to get out of our horrific drought in California or at least make a big dent in it?  One of the biggest misconceptions when it comes to El Niño is it ALWAYS brings rain.  There is the belief that every El Niño will be like 1997-98 or 1983-83 when downtown Los Angeles received 30 plus inches of rain during the water year.  The atmosphere is not that simple.  Some El Niño seasons have been dry, some wet, and others are somewhere around average.  Going back through 1950, we have seen 22 seasons with an El Niño, 12 had above-average rainfall and 10 were below-average.  This data shows a slight trend toward wet winters, but you can see it is far from a guarantee.  This is the part of El Niño that is impossible to predict.

2015_Significant El Ninos

However, the one strong correlation to getting the rain we need is if we get a significantly strong El Niño.  Check out the above graph and how all significant years brought well above average rain amounts.  If El Niño forecast continues in this direction I do think we will receive a tremendous amount of rain this upcoming winter.  To get out of our drought in California we need widespread amounts of two feet just to get back to normal.  If we get that in one season we’ll get flooding and mud slides.  We also need more than just rain.  We need our northern California mountains to get snow.  A concern I have is, if the temperatures are too warm, we’ll get a lot of rain but no snow.  The snow in the Northern Sierras is our year-round water supply for families and farmers.

ElNino_Compare

Check out how our July water temperatures compare to the El Niño of 1997.  That year was warmer and more widespread from the waters of South America, but the two are fairly close.  An interesting note: Hurricane Dolores was able to keep its circulation as it moved closer to southern California because the warmer waters in North America kept it from completely dying.  It was Dolores, along with a monsoonal flow, that brought about record-setting rain July 18th and 19th.

2015_El Nino Hurricane

In any El Niño season we see an increase in Pacific hurricane activity and a decrease in the Atlantic.

2015_Drought Monitor

Even with the record-setting July rain, there is no recognizable dent in the drought.  We went from 47% exceptional drought to 46%.

2015_El Nino Effects

What is interesting for Los Angeles in particular is we also don’t get as many 90-degree days in the summer.

2015_What Is El Nino

El Niño is a warming of the water off the Pacific coast of South America.  El Niño’s are categorized by their strength, ranging from weak to very strong.  This past winter was a weak El Niño.  No two El Niños are alike.

Special thanks to David Biggar for the graphics and research.

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One Response

  1. miss you much! great explanation!

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