The 2014/15 El Niño – Part 8 – The Southern Oscillation Indices

Eric Worrall says: “I live in Hervey Bay, on the East coast of Australia. The last week or so has been cold and set – unusual weather for a subtropical region, and not what you would expect if the surface waters of our end of the Pacific were heating up.
Wouldn’t be surprised if this El Nino were a fizzle.”
Eric, we had a blast of Antarctic air cool things off. It’s kinda hard to feel the ocean heat when you’re getting blasted with polar air. While it is a bit unusual in this part of the world, it isn’t unheard of.
I think you’re right that the much anticipated El Nino will fizzle… but failed predictions are soon forgotten, and I’m sure they’ll be back next year with new predictions and updated graphs.

It is definitely appalling to see the vast number of individuals here who are somehow trying to convince themselves of no el nino this year (or a weaker one) despite much of the evidence to the contrary.

Bob, Interesting review again, as usual from you. In reading many of the comments I get a bit frustrated as some of the folks really don’t understand WEATHER in the South Pacific. While Trenberth doesn’t seem popular here he really is an outstanding Tropical Forecaster with texts published on the subject. His comments on the SOI and MJO are spot on and there much more that affect the index as he indicates. I think what is confusing for some of the commenters is the use of anomalies instead of looking at real data. As I have mentioned in numerous comments, I do this every day when I forecast. While the MJO is cyclic and certainly skews the SOI so do the traveling Anticyclones which affect the SOI even more. When an intra-anticyclonic trough is over Tahiti and an Anticyclone is near Australia the index anomaly would be negative (pressure lower in Tahiti, higher in Darwin), but the reality is the WINDS still blow east to west. The only time we see west to east is during an MJO or the North side of a traveling Depression. The later occurs nearly every 7 to 10 days, but the northern extent of these winds usually doesn’t go north of 15 to 20S. The MJO is most active in the Austral summer (eg Dec, Jan, Feb) and weak in the Austral winter, which is now. So the chance of a big ‘westerly wind burst’ along the equator at this point is pretty slim.
The other item that seems to be confusing folks is the talk of equatorial trades. There are really no equatorial trades to speak of. This area is the Doldrums or Horse Latitudes (named because being an area of no wind ships of old had to toss the horses overboard because there wasn’t enough water). To confuse even more there are two equators. The geographic one and the meteorological one. The later is the ITCZ which changes latitude; mostly north of the geographic one east of the dateline but can go south of the geographic one west of the dateline. The ITCZ is fed by NE winds on one side and SE winds on the other, in the main. The meteorological ITCZ east of the dateline corresponds to the ‘equatorial counter current’.
As many have noted the ‘Null School’ site is a good one to see streamlines . It’s then that you’ll get the idea of watts up with the wind and how much it affects ENSO.
And lastly I too recommend your book, it’s worth it folks.

Jack, you just prove my point in trying to convince yourself of what’s going on here & are simply letting your AGW views skew your view on this upcoming El Nino event. It’s also ironic you mention that I’m a “kid”, yet your rant above reveals your maturity level is equatable to that of a child. Let’s just remember that you & many others here didn’t even think an el nino was coming to begin with several months ago, but that has clearly changed, and to say that AMJ is off the table is somewhat delusional on your part as you have once again failed to look @ur momisugly any actual data of the ENSO regions, you’d be able to see that we’re virtually @ur momisugly .5C marker now, & the AMJ period is a tri-monthly average, so the fact that we are almost to that point in the beginning of the 2nd month bodes well AMJ starting point. In addition, the SOI is as Bob has stated above is among the nosiest ENSO indicators & although it isn’t common for us to see positive spikes like this in Apr, it’s not entirely unheard of as both the 1957-58 & 1986-87 El Nino events, strong & moderate respectively in intensity, observed a +SOI spike in Apr following -SOI bursts earlier in the year. If anything, is “fizzling” its the easterly trade winds, which with the passage of each successive MJO pulse, have been decaying in the Pacific, especially in the regions east of the international dateline.
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/u850_c.gif
The first Kelvin Wave was historic and has completely altered the base state of the Pacific to the point that even when the periodic WWBs in the wake of the mean convective signal associated with the MJO start to decay, you’re still going to end up with mean westerly surface currents. Also, the warm upwelled water has kick-started the classic Bjerknes Feedback process, & as result, the MJO is starting to become biased towards the Pacific & Western Hemisphere (Phases 7-1) and TRMM rainfall anomalies reveal that an El Nino like precipitation pattern has already evolved in the tropics with a wavenumber 2 precip pattern featuring drier conditions over the Maritime Continent & Tropical Atlantic with 2 regions of opposing wetter than normal conditions & upward motion generally over the Pacific & African Sahel.
http://trmm.gsfc.nasa.gov/trmm_rain/Events/new_anomaly.gif

Thanks Pamela,
I’m going to try spraying some weeds while the wind isn’t blowing 40 mph, so will read that this evening. I am an unpaid volunteer trail worker with Washington Trails Association (WTA.org) and the massive runoffs provide job security with the need for bridge replacements and trail relocations.

Eric, You need to check those trade winds again and the SOI.
May 7th -18.52
May 8th -12.08
May 9th +04.77
May 10th +13.81
May 11th +23.61
See a pattern?
All you ever had was the kelvin wave. Even with the kelvin wave surfacing, the eastern pacific is still colder than 1997. The 3+4 is still stuck in neutral, literally. The trades are strong again, so I don’t see that changing this week. So good luck with your A-M-J.

Weather Dave says:
May 11, 2014 at 11:19 am
“. . . The other item that seems to be confusing folks is the talk of equatorial trades. There are really no equatorial trades to speak of. This area is the Doldrums or Horse Latitudes (named because being an area of no wind ships of old had to toss the horses overboard because there wasn’t enough water). ”
The Horse Latitudes and the Doldrums are not the same. Today the terms are respectively SubTropical High Pressure (STHP) and Intertropical Covergence Zone (ITCZ). The latter is the one mentioned in Coleridge’s “Rime of the Ancient Mariner.”
Now to the naming of the Horse Latitudes: I wrote the following to a friend sometime back and hope we are far enough along in this thread that the Boss and Bob T. won’t mind me adding it here; it is a bit long:
To a friend:
Here is the long story about how I got to the site mentioning the compression of cotton bales (aka cotton-screwing) and the chants by which the timing of turns on the jack-screws was done.
I have taken and read many historical things, and included are history of science and history of geography. From the history of science side comes the fact that when Galileo investigated the force of gravity by timing a ball rolling down an inclined plane – clocks accurate enough to do this had not been invented.
Answer is here:
http://www.mcm.edu/academic/galileo/ars/arshtml/mathofmotion1.html
Any geography book that mentioned the “Horse Latitudes” usually explained the name using a story about sailing ships getting caught in calm areas and then throwing horses overboard to save water for the humans. One text gave a second account, namely that the English word “horse” can be a verb in the sense one might have “to horse” something heavy this way of that way by pushing or tugging on it. Becalmed sailing ships could be “horsed” from a calm area to one more breezy by tugging on it from a rowed boat. That sounds fun.
The book, wherein this was, finished by saying the world might never know which of these explanations was the truth. Along about the 40th year of teaching classes that include explaining the horse latitudes, I explained the 2 possible explanations for the term. A non-traditional student (somewhat older and more experienced than the average freshmen) offered that he could suggest a third explanation. He did, and the next class meeting he brought a thick book on sailing ships, rigging, stories, and work songs or shanties (also chanteys).
So now there are 3 explanations and not much guidance for selecting one over the others.
Over the years I’ve thought of this and wondered. In no particular order here are some thoughts.
Most maps of the route Columbus took to “America” are useless – wrong projections or just simple cartoons. In any case, the 3 ships started and headed more south than west – Columbus did not attempt to sail “west to America.” Had he gone west he would have sailed directly into the high pressure zone. He had to know that it was there! How?
Apparently, he knew this by talking to or sailing with people that already knew about the Atlantic Ocean:
http://en.wikipedia.org/wiki/Grand_Banks#History
Then there is the idea that Spanish ship captains ordered horses thrown overboard. The two problems are: 1. There is at least one classic painting (I’ve seen a photo, WSJ, about 10 years ago) of the unloading of horses when arriving in the New World. It is a great painting of a beautiful horse, rearing, as he is led to an opening in the rail and invited to leap into the sea. Without wharf or quay the unloading is accomplished in deep enough water to accommodate a plunging horse. It would be easy to make up a story about this if one did not know what was happening. 2. Back to the name: We don’t call these places the Caballo Latitudes or Yegua, or é gua (or a gender neutral noun). Maybe that’s because the Spanish did not find such places of interest and knew enough to stay out of them.
Well, I think the English sailors knew that too. Would sailors repeatedly go into an area of calm seas, find themselves becalmed, and then “horse” their way out with oars and a line. Not likely. If they did would they return to port and brag about it? Not likely.
English history tells of ships about to leave and needing sailors. It is romanticism to believe that lots of folks wanted to leave and maybe not come back. The word “nap” with the word “kid” in front suggests one way of getting sailors. But napping also involved going to pubs and hauling off passed-out men – as long as the ship’s representatives paid the drunk’s bar bill. This cost was called a “horse” or “dead horse.” Another source of “horse” in this sense was a purse given to the wife and family of a man about to go to sea – this would be about one month’s wages.
Ships would sail south from England and many of the men were paid ahead in the sense of the above paragraph. After a few weeks of sailing this pre-payment (“the horse”) would have been taken care of by their work – following which they would be given credit until a port was reached or they returned to England and were paid after the sale of the acquired cargo.
Into the voyage, at the point where the horse had been paid a straw (wicker) horse would be raised and swung over the rail. The celebration would reach its apex as the line was cut and the representation of “the horse” was sent drifting in the sea. Someplace I have some material on this with a line drawing of the ceremony but most folks have concentrated on the words and the timing of the chants and the fact that having everyone pull at the exact same instant could be achieved with this simple method.
Until, shown a better alternative explanation I favor the shanty and the floating straw form as the source of the term Horse Latitudes.
In class, I would tell students that the characteristics of these calm areas should be the things to remember and if floating dead horses helped them – all was good.

@ur momisugly Jack
The trade winds undergo week-week variability in intensity, however, when looking @ur momisugly ENSO it is better to observe the overall trend, & in the last few months, the trend clearly indicates substantial weakening that favors a rapid start to El Nino
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/u850_c.gif
In addition, the evident flattening of the thermocline & eastward propagation of the 28C isotherm is a clear indicator that El Nino is upon us http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/anim/wkxzteq_all.gif

Eric, I never predicted that there wouldn’t be an el nino. You need to stop living in your bubble. I said there would be a weak one. The problem with you is that you project. This way you can just dismiss anything that doesn’t conform to your belief. It allows you to remain morally superior. Adjusting your beliefs becomes unnecessary this way, because you are always right and when someone disagrees with you than it is because they are biased or there is a flaw in their thinking. This is not a sign of brilliance, it’s a sign of immaturity.
June-July-August (1.3 to 1.6 C) and it lasts 9 to 11 months, my guess. 2.0 to 2.3 C is ridiculous, in my opinion. Nothing exists which would justify that. One strong kelvin wave won’t do that. The problem with you is you don’t want to admit you’re wrong.