El Niño, California Drought, and Predictions

El Niño, California Drought, and Predictions

Modified on 20141029

Back in May 2014, I wrote a couple of blogs about El Niño predictions for this year (Tracking El Niño and Underlying Models). In July, I did a summertime update. For those who need it, there are links to basic information such as definitions of terms in those blogs. This entry is an update.

As most of my readers already know, the excited, exaggerated springtime predictions have not come to fruition. The current prediction status, from the links below, is that there remains a chance of a weak El Niño. As I have followed the El Niño forecast, I have found the products and guidance from the Australian Bureau of Meteorology to be the clearest and most usable. Their discussions are short, and compared to many other centers, their language does not fall quickly into either jargon or graphics that require a high level of expertise to interpret.

The latest Australian forecast is “Given current observations and model outlooks, the chance of a late season El Niño remains at least 50%, which is double the average likelihood of an event occurring.” I am going to try to break this down some. The first part of this forecast is telling me that the probability of a set of criteria that define El Niño is a little more than half. On the flip side, of this slightly warped coin, the probability that El Niño neutral will persist is a little less than half.

The other part of this sentence “which is double the average likelihood of an event occurring,” is a little harder to explain. If you look around the summaries from the different centers, then they say that the current measurements of the ocean and atmosphere are El Niño neutral, but there are a number of descriptors that, though measured as “neutral,” are tilted towards the El Niño condition. This is mostly related to the temperatures in the eastern Pacific being warmer than average. That is, we are close enough to El Niño that it's twice as likely to become an official El Niño than if we were smack in the middle of neutrality. The ocean and atmosphere are flirting with an El Niño.

The predictions from most centers are that if there is an El Niño, then it will be a weak El Niño. At most, there might be a moderate El Niño. (Again, if you need to know terms and definitions, I refer you to the links in the first paragraph.)

OK, no monster, super, or even strong El Niño. I remind you from the May 20, 2014 entry, “Note, none of these centers are predicting, yet, strong, super or monster.” All of that exaggeration came from elsewhere. And, perhaps tediously, as was the case in my cranky response to the return of the polar vortex, the increasing exaggeration and personification of weather events and their implications for climate change are distinctly negative contributions (link to my analysis). I rely on The Onion’s description of the deadly super rainbow to finish my point. (from my former student Evan O)

In my entry from May 29, 2014 I wrote, “even a moderate El Niño this year is likely to lead to the hottest year on record.” My rationale for this statement is that we are living in the hottest decade since we have had easily defended direct temperature measurements. We have remained warm, globally, despite relatively cool temperatures in the eastern Pacific. Given the importance of the eastern Pacific to the global picture, even a small break in the cool pattern is likely to lead to globally historic highs. Let’s do a summary, since modern temperature records began in 1880:

April 2014 the warmest April
May 2014 the warmest May
June 2014 the warmest June
July 2014 not quite the warmest July
August 2014 the warmest August
September 2014 the warmest September

(A short summary for NASA Earth Observatory) modifications ... There are some differences in the different records of the actual records on a month by month basis. It's worse than a football poll. Here is NOAA's Accounting which counts April as second warmest. Here is Deke Arndt on 2014 Temperatures. end modifications

At this point it will take the intervention of the Snow Queen to derail this year from the record books. My statement in the earlier blog was only me stating the self evident, I want to go back and give credit to Judith Lean and David Rind. Their analysis in 2009 laid out the story line that I am following (Bumps and Wiggles)

OK, California. When there was a prediction of a strong El Niño back in the spring of 2014, there was a lot of chatter about an El Niño breaking the California drought. Returning to the interpretation that I did of the Australian Bureau of Meteorology’s El Niño forecast, when there is an El Niño, the likelihood of rain (heavy rain) in California, in winter is higher. That does not mean that if there is an El Niño, that it will necessarily rain. It is also possible that there will be rain in the absence of an El Niño. There is a good blog from KQED in San Francisco about the reliability (or not) of the relationship between El Niño and California rain.

A couple of people have asked me what I think about the drought, El Niño, and this winter – like I should know. I remember back in 2013, March, sitting in Colorado following a very dry year, 2012. I was pretty much giving up on the garden, looking at a fall back of using city water on a very small garden, expecting water restrictions to be imposed. In fact, municipalities around Denver were imposing mandatory restrictions. Then in April of 2013, there was record snow. The mountains were laden with water. Then in September of 2013, there was flood. In this little spot, by no means the entire state, there was water. This year, 2014, the ditches were flowing later than I have every seen, but that’s not much of a measure. Such events make you exquisitely aware of the quixotic behavior of weather. I recall several instances in my life where drought was upon us, the reservoirs were drying, and then there was a singular event and reservoirs were full.

With that as a caveat, I am going to imagine that I have small farm near Cloverdale, California. If I were looking to the skies for water, I would be preparing for continued drought. What is going on with the El Niño forecasts does not support the easy hope of El Niño or rain and snow. The seasonal forecasts for California have been showing above average this winter in Southern California (link). My casual observation is that the western half of the U.S. is headed towards more of that persistent flow that keeps California dry. Even if there were enormous rains, they are not likely to extend across all of the watersheds required to fill California’s needs. It will take time to restore that part of the groundwater that can be restored.

I close with a mention of NOAA’s ENSO Blog. Emily Becker wrote an entry on October 9, 2014 entitled Details on the October ENSO Diagnostic Discussion: Trust, but Verify.

r

I like the effort from the Australian Bureau of Meteorology to summarize the criteria for El Niño and La Niña watches, alerts and existence, in addition to the neutral phase.



Figure 1: ENSO Tracker indicating an El Niño WATCH (left) and El Niño ALERT (right). Far more details from Australian Bureau of Meteorology. In the July 29, 2014 update, the Australian Bureau of Meteorology shifted from Alert to Watch

Forecast and Analysis Centers

Climate Prediction Center Alert System and the Climate Prediction Center Diagnostic Discussion

International Research Institute Forecast Products and the Quick Look

Japanese Meteorological Agency El Niño Monitoring and Outlook and a nice graph of historical events

Australian Bureau of Meteorology Wrapup

Netherlands Meteorological Institute (KNMI) Forecasts

Information Portals

CLIVAR (Variability and predictability of the ocean-atmosphere system) Forecast Page

World Meteorological Updates

Pacific Marine Environmental Laboratory El Niño Theme Page Forecasts

Climate Prediction Center FAQ

NOAA’s El Niño Page and NOAA’s La Niña Page

Summaries in Blogs

Judy Curry El Niño Watch

NOAA’s ENSO Blog

Rood’s Just Temperature Series

Just Temperature 3

Just Temperature 2

Just Temperature 1