Guest Post by Bob Tisdale
The recent post at WattsUpWithThat Yes Virginia (and everyone else) there is an El Niño coming was written by Joe Bastardi of WeatherBell Analytics. As a result of that article, Joe and I exchanged a good number of emails. Once again, Joe Bastardi was more than willing to teach from the perspective of a professional meteorologist. Joe took the time on a Sunday afternoon during (U.S.) football season to discuss El Niños and forecasting with me. Thanks, Joe.
The 2014/15 El Niño has to be one for the record books. It has probably been one of the most-observed and most-studied weak El Niño events ever. It started early in the year with a large Kelvin wave (discussed in the first post of this series). Alarmists around the globe began predicting all sorts of mayhem… to be brought on by what they assumed would be a “super” El Niño…which, in turn, they claimed was caused by, and made worse by, human-induced global warming. Contrary to all the prognostications of gloom and doom, the El Niño fizzled into weak El Niño conditions during the boreal spring and summer, destroying all of the alarmists’ hopes and making some persons look exceedingly foolish… exceedingly foolish.
But one of the “constants” throughout the year has been Joe Bastardi’s forecasts that this El Niño would not be a strong event—that the El Niño would reach only weak to moderate levels.
You may, at this time, be saying to yourself, What El Niño? The El Niño hasn’t developed yet.
It depends on how we’re defining an El Niño—which index we’re referencing. That’s the topic of this post.
Now, this discussion would not be taking place if a super El Niño had developed. But that never materialized.
You may also be thinking, If it’s not a super El Niño, why do we care?
The tropical Pacific influences weather around the globe, regardless of whether the sea surface temperatures for a specific region are above or below El Niño and La Niña thresholds. In addition to the numerous other factors that dictate your regional weather, meteorologists have to rely on many indicators from the tropical Pacific when preparing their seasonal forecasts, not just the sea surface temperatures of a specific region along the equator.
I learned a good number of things from Joe Bastardi during that email exchange, but on the topic of El Niño, one of points he stressed was, I was limiting my definition of an El Niño to the one based on the sea surface temperatures of the NINO3.4 region—the classic NOAA definition. NOAA uses the sea surface temperatures of the NINO3.4 region of the equatorial Pacific for their Oceanic NINO Index (ONI) and for their classifications of “official” El Niños and La Niñas.
NOAA defines El Niño conditions as sea surface temperature anomalies of the NINO3.4 region equal to or higher than +0.5 deg C. And as of last week, the week centered on Wednesday, October 22, sea surface temperature anomalies were once again back at the threshold of El Niño conditions. Let’s expand on that.
This year, NINO3.4 sea surface temperature anomalies barely squeaked into weak El Niño conditions during the boreal summer, then dropped back toward zero, but have returned once again to the threshold of El Niño conditions…according to the weekly data. Whether the sea surface temperatures there remain at or above that threshold long enough for NOAA to classify this year’s event as an “official” El Nino has yet to be seen. (And that was how I was limiting my view of an El Niño.)
ANOTHER OF THE CURIOSITIES THIS YEAR
Figure 1 is a map of the average sea surface temperature anomalies of the tropical Pacific for May through September 2014. Highlighted on the map are the four NINO regions. More than a decade ago the NINO3.4 region was selected for use as the primary NINO index. In the 1997 paper The Definition of El Niño, Trenberth notes:
Mean temperatures are higher in the Niño 3.4 region than in Niño 3 and its proximity to the Pacific warm pool and main centers of convection is the reason for the physical importance of Niño 3.4.
Figure 1
This year, from May to September, the equatorial Pacific has warmed east and west of the NINO3.4 region, as shown in Figure 1. To expand on that:
The equatorial Pacific stretches almost halfway around the globe. NINO regions occupy the central and eastern portions. And while the weekly sea surface temperatures of the NINO3.4 region have occasionally reached El Niño conditions this year (just barely), the monthly values have not. See Figure 2. But the sea surface temperature anomalies for the entire central and eastern equatorial Pacific (5S-5N, 160E-80W) have been at or above +0.5 deg C since May 2014, with most of the warming taking place in the far eastern equatorial Pacific.
Figure 2
For some reason, the NINO3.4 region hasn’t been cooperating, but east and west of it, the equatorial Pacific has been in El Niño conditions for a good number of months, with the sea surface temperatures in the NINO1+2 region continuing to remain elevated and with the NINO3 and NINO4 regions cycling into El Niño conditions, back out and back in. See Figure 3. In fact, the NINO3 region reached the +1.0 deg C threshold of a moderate El Niño for a couple of weeks.
Figure 3
NOAA focuses in the NINO3.4 region with its Oceanic NINO Index, so many people, like me, also focus on it. This year, the (weak) El Niño conditions have been taking place east and west of the NINO3.4 region. Very curious.
THE 90-DAY SOUTHERN OSCILLATION INDEX IS ALSO SHOWING WEAK EL NIÑO CONDITIONS
As of October 30, 2014, the 90-day Southern Oscillation Index (SOI) value has been within weak El Niño conditions for more than 1 week, where a negative SOI value equal to or more negative than -8.0 is considered El Niño conditions.
Let’s phrase that another way: Based on the average 90-day SOI, weak El Niño conditions have existed in the tropical Pacific for the past 3 months.
CAN’T FORGET THE MULTIVARIATE ENSO INDEX
The Multivariate ENSO Index (MEI) is another ENSO index published by NOAA. It was created and is maintained by NOAA’s Klaus Wolter. The Multivariate ENSO Index uses the sea surface temperatures of the NINO3 region of the equatorial Pacific, along with a slew of atmospheric variables…thus “multivariate”.
According to the most recent Multivariate ENSO Index update discussion (my boldface):
The long anticipated emergence of El Niño conditions in 2014 has been under way since May-June, despite the lack of signal in Niño 3.4 SST…and its sudden drop in the MEI this month.
The MEI had been showing El Niño conditions for the three bimonthly periods (May-June, June-July, and July-August) before dropping out in August-September.
BUT…
…(big but), keep in mind that El Niño and La Niña rankings according to the MEI aren’t based on fixed threshold values such as +0.5 for El Niño and -0.5 for La Niña. The MEI El Niño and La Niña rankings are based on percentiles, top 30% for the weak to strong El Niños and the bottom 30% for the weak to strong La Niñas. This is difficult to track, because, when using the percentile method, the thresholds of El Niño and La Niña conditions vary from one bimonthly period to the next, and they can change from year to year.
As a clarification, looking at the numerical values of the MEI timeseries, the 19th ranked positive MEI for AugSep is 0.526 (through 2014), but for the next three bimonthly periods (through 2013) the 19th ranked positive MEI’s for SepOct is 0.638, for OctNov it’s 0.645 and for NovDec it’s 0.559. It would be interesting to know why Klaus Wolter uses percentiles instead of fixed thresholds.
I’ll have to add the MEI to my next few monthly El Niño updates.
BOTTOM LINE
NOAA’s primary ENSO index (NINO3.4 sea surface temperature anomalies) is not indicating that we’re in weak El Niño conditions. And, when all is said and done next year, it’s entirely possible that this year’s El Niño won’t be highlighted in red on the Oceanic NINO Index. But that does not mean weather conditions are not responding to the other factors that contribute to an El Niño, where
- other factors include those considered by the Southern Oscillation Index and Multivariate ENSO Index, and
- other factors that are impacted by the sea surface temperatures of the other NINO regions east and west of the NINO3.4 region.
It all boils down to what one uses to define an El Niño and how one uses that information when making a long-term weather forecast…which is where Joe Bastardi excels.
POSTSCRIPT
Just a quick animation of the last two months of subsurface temperature anomalies graphics along the equator, from the NOAA GODAS website: As noted in the last two updates (here and here), there has been a strengthening of the latest downwelling (warm) Kelvin wave. That warm water should continue to travel east and be drawn to the surface over the next few months.
Animation 1
EARLIER POSTS IN THIS SERIES
- The 2014/15 El Niño – Part 1 – The Initial Processes of the El Niño.
- The 2014/15 El Niño – Part 2 – The Alarmist Misinformation (BS) Begins
- The 2014/15 El Niño – Part 3 – Early Evolution – Comparison with 1982/83 & 1997/98 El Niño Events
- The 2014/15 El Niño – Part 4 – Early Evolution – Comparison with Other Satellite-Era El Niños
- The 2014/15 El Niño – Part 5 – The Relationship Between the PDO and ENSO
- The 2014/15 El Niño – Part 6 – What’s All The Hubbub About?…
- The 2014/15 El Niño – Part 7 – May 2014 Update and What Should Happen Next
- The 2014/15 El Niño – Part 8 – The Southern Oscillation Indices
- The 2014/15 El Niño – Part 9 – Kevin Trenberth is Looking Forward to Another “Big Jump”
- The 2014/15 El Niño – Part 10 – June 2014 Update – Still Waiting for the Feedbacks
- The 2014/15 El Niño – Part 11 – Is the El Niño Dying?
- The 2014/15 El Niño – Part 12 – July 2014 Update – The Feedbacks Need to Kick in Soon
- The 2014/15 El Niño – Part 13 – More Mixed Signals
- The 2014/15 El Niño – Part 14 – Warm Water Recirculated?
- The 2014/15 El Niño – Part 15 – August 2014 Update – An El Niño Mulligan?
- The 2014 15 El Niño – Part 16 – September 2014 Update – Still Seeing Mixed Signals
- The 2014/15 El Niño – Part 17 – Is There Still Hope for a Moderate El Niño?
- The 2014/15 El Niño – Part 18 – October 2014 Update – One Last Chance?
And for additional introductory discussions of El Niño processes see:
- An Illustrated Introduction to the Basic Processes that Drive El Niño and La Niña Events
- El Niño and La Niña Basics: Introduction to the Pacific Trade Winds
- La Niñas Do NOT Suck Heat from the Atmosphere
- ENSO Basics: Westerly Wind Bursts Initiate an El Niño
Weather Dave
I too like to review what BoM say. Here is their outlook as of October
“Three of the eight international climate models surveyed by the Bureau indicate the possibility of ocean conditions reaching El Niño thresholds by mid-summer, with the remainder favouring persistence of neutral conditions. The models which indicate a possible El Niño forecast peak central equatorial Pacific SSTs reaching at most moderate El Niño levels. ”
Three out of eight is poor odds for an El Nino in my opinion.
It is interesting when one looks at the plot of the POAMA MODELS monthly mean NINO3-4 FORECAST, the ensemble mean curve does not exceed 0.4 until about March of 2015 and only gets to about 0.6 – 0.7 by about June 2015. It seems that even the models as an ensemble do not predict an El Nino THIS WINTER at this time .
Bob Tisdale, thank you for another informative post.
El Niño conditions have been evident for at least three months in Eastern Australia. I’d say we have one but a weak event and for my own sake that it breaks down in March/April. It’s a tad difficult to grow crops without sufficient rain and we need big opening falls to replenish sub soil moisture.
Thank you Bob!
The Eagles must not have been playing’ Joe’s a South Philly fan.
Judging by the Autumn we have in Laramie, my answer is yes.
We have El Nino LIKE conditions here in Canterbury NZ.
Very sunny and very dry for the last two months.
Is an El Niño Already Taking Place?
Depending on people’s private definition, yes or no. According to the CPC definition absolutely no.
Not necessarily private definitions, FergalR. When all is said and done, the BOM may say that there had been a weak El Nino. based on the SOI.
Bob
Thanks for the further clarification about the recent unusual nature of the events in the Pacific. Whether all this turns into an El Nino this winter, we will just have to wait and see .
So everyone is right to a degree or another… LOL science at work!
Guano birds carrying horse mackerel at NOAA it seems. Spare bottle of Lea & Perrins in the canteen cupboard too no doubt. Full English breakfasts served all day.
Nice post Bob, you are such a great teacher.I have learned so much from you.I can not fully express my thanks and appreciation here.
El Nino is bad news for Australia as the populated Eastern States are affected by drought during the event. Right now there is much rain throughout the entire Nation sweeping from West to East, week in week out which is unusual, this has been happening for months now where once the rain was not inland but coastal. However the rain along the Eastern Coast has been virtually constant for years and is brought on by Southern High Pressure systems moving from West to East.
No sign of it stopping just yet.
http://www.eldersweather.com.au/synoptic/
East coast rain is often a result of dominant blocking Tasman Sea highs that cradle lows againt the coast while the inland remains very dry and is often associated with El Niño. The vast expanse of SE Australia has been in a decile one for precipitation for many months. Your post is at odds with the current situation.
Interesting discussion. No two el Ninos are alike especially ones with borderline existence. Twenty posts (almost) on an el Nino that only exists when we shift the goalposts! Why are we following an agenda of AGW desperation for el Nino? It is what it is.
Some weeks ago it was pointed out that Peruvian upwelling had returned and with it the anchovies were increasing. For me the anchovy tonnage landed in Peru has equal importance to any meteorological index of el Nino. With upwelling and the anchovies back, the el Nino was dead and buried.
We are overthinking ENSO by adding more and more multivariate parameters. ENSO at its core is the Bjerknes feedback which involves just two things: Peruvian upwelling, and the trade winds. Everything else follows from those two.
All our models and thinking about ENSO have developed during a single warming el Nino dominated PDO warm phase since 1976. Now we are moving into a different Pacific ground state and will have to learn about new dynsmic processes.
Why the excess warmth in the east and west Pacific? Maybe it is linked to the anomalous high latitude cold SSTs both north and south. Perhaps transport of ocean heat poleward from the equator is slowing?
I am following it because I want reservoir replenishment in Cali (plus snow to ski on) and because following it so intricately is contributing to our future predictive capabilities. Your assumption of the motive for interest is an inaccurate generalization (redundant).
The trade winds have turned westerly from 160°- 180° and are looking weak to the east http://www.bom.gov.au/climate/enso/sst_wind_anom_5day.large.gif
I am puzzled by the temperature convergence of the equatorial regions in Fig 3. Nino1+2 has been cooling for approximately 18 weeks. A mixed bag of signals for sure, but the trade wind change is very interesting and will be worth watching.
Has El Nino already formed ? The trade wind change would indicate so.
Keith Minto
This is the same graph that the Australian BoM used to make the comments that I noted earlier I my previous post, namely,
ENSO Update :
“Trade winds are weaker than average over the western half of the tropical Pacific and near-average over the remainder of the tropical Pacific .
During La Niña events, there is a sustained strengthening of the trade winds across much of the tropical Pacific, while during El Niño events there is a sustained weakening of the trade winds. ”
There is nothing new in your comments here.
If you go to http://earth.nullschoo.net/#current/wind /surface
You will note that the surface winds are mostly blowing east
I should correct my previous post
You will note that the trade winds are blowing mostly west[not east]
That web page should read
http://earth.nullschool.net/#current/wind/surface
El Nino, La Nina are created by external forcings (wind mostly) that (on a localized basis) alter the thermocline and natural lapse rate in ocean temperatures from what one would expect in an idealized entropic system. The boundary layers created in warm and cool pools have their own entropic characteristics which further effect the rate of achieving overall equilibrium.
“Forcing” cuts both ways. The winds force the oceans. The oceans force the winds. Its a connected system, which, with nonlinear dynamics thrown in, also forces itself.
I’ve noticed for some time now that anything on the plus side of ENSO neutral tends to produce somewhat above average rainfall in California. It’s the major El Niños that produce the 200% years. I still say we’re better off with average or a little above average rainfall because there are fewer flooding type storms with damaging winds but still enough rainfall to fill the reservoirs. A weak El Niño for the 2014/15 rainfall season might just be perfect.
Unfortunately less intelligent humans learn little about climate from their parents or grandparents and seem bent on being forced to learn the same lesson over and over again. The only way to stop that short cycle is to require each generation to care for grandparents as soon as they hit the age of 18. Let’s call it the new draft into service. Maybe we could stop this cyclic madness that every generation of nitwits seem bent on spreading: Oh its freezing! We caused it!!! Oh its heating up! We caused it!!!! Oh we are sinning and the world will end!!! And we caused it!!!!!
Please Lord give me a fricken break from the “current generation”.
Latest …
1. Troup’s SOI
2. Pressures
I have to respectfully disagree. There neither is now, nor is there going to be, an El Niño this year (much as it pains me to say it). These pre-El Niño-like symptoms we’re witnessing are only natural aberrations and not the full-fledged event.
Mr. Tisdale,
I would love to see a video of your discussion with Joe Bastardi along with the graphs you were discussing. That would be a great educational experience.
Why is it that many data sets that show present temperature anomalies used the the 1971-2000 data set. it is well know the globe was cooler from the forties thru the mid seventies. With the temperature inertia of the oceans being so massive is it fair to use a number that stats out cold?
Keith Minto. I will add to Herkimers comment regarding easterly winds. There have been no westerly winds of any significance in the SW Pacific. The only westerlies that have occurred are those from a passing depression or tropical disturbance. I think that you possibly confuse ‘anomalies’ with actual wind. I have always found that in meteorology anomalies can quickly give a novice the wrong idea. For those interested in SW Pacific wind forecasts try http://www.metvuw.com/. This is from the Univ of Victoria in NZ who use GFS. I am a tropical forecaster and use UK Met, ECMWF, GFS and a French Model that has proved quite valuable to me. BoM does not forecast east of the dateline so their data is of limited value. However back to the winds. The other cause of any westerlies, that last for only a week or so, come with an MJO pulse which has not been active at all recently.There are a few other causes but are trivial.
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