ENSO Updates (2007 thru 2023)

[tolakram]

Interesting that this is all happening while the US east coast is going through an unprecedented heat wave. The kink in the jet stream is perhaps responsible for increasing winds in the pacific, cooling things off?

Jet stream analysis (direct link unfortunately, can't access imageshack from here).

from: http://squall.sfsu.edu/crws/jetstream.html


I guess I should ask if the unusually strong ridge might be increasing winds in the pacific.

[cycloneye]

Another sign that the cooling of the waters may not be temporary is the 30 day SOI index that is rising after dropping almost to negative by mid to late Febuary.



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[OURAGAN]

[OURAGAN]

http://www.bom.gov.au/climate/enso/soi.txt

[Kingarabian]

I'm still confident of getting an El-Nino. We had the same thing happen in 09-10 season where El-nino started to fade then became alive again, then it quickly faded away.

[Kingarabian]

Models still support an El-Nino as well.

[cycloneye]

Here is the Mid-March update of all the ENSO models that shows only 4 of them crossing the +0.5C threshold of El Nino.The rest are at Warm Neutral in August,September and October.

Expected Conditions
What is the outlook for the ENSO status going forward?
The official diagnosis and outlook was issued earlier this month in the NOAA/Climate Prediction Center ENSO Diagnostic Discussion, produced jointly by CPC and IRI. Now, in the middle of March, a new set of model ENSO predictions is available as shown in the IRI/CPC ENSO prediction plume, discussed below. The current east-central tropical Pacific SSTs have continued to be below average and at a level indicative of La Niña, but have been warming toward the -0.45 threshold that would mark reentry to neutral conditions. Subsurface temperatures across the equatorial Pacific have weakened to near-average during late February and early March, both because of weakening of the cold pool beneath the surface in the east-central tropical Pacific and the development of above-average water temperatures near and at the surface in the eastern portion. The currently weak La Niña condition is expected to dissipate during late March or early April as the coupled system returns to neutral and the west-to-east SST anomaly gradient from just west of the dateline to near the South American coast weakens due to the expected dissipation of enhanced low level easterlies west of the dateline and weakening of the current westerly anomalies associated with the above-average SST in the eastern part of the basin.

As of mid-March, most of the dynamical and statistical models predict below average, but ENSO-neutral, conditions for the Mar-May season, while only a few continue to show weak La Niña condition. All models indicate warming from their starting anomaly values. For the Mar-May season, 21% of the models indicate La Niña conditions, and 79% indicate neutral conditions. For Apr-Jun, these figures become 8% and 92%, respectively. Jumping ahead to Jul-Aug-Sep, 73% indicate neutral conditions and 27% predict El Niño conditions. At lead times of 4 or more months into the future, statistical and dynamical models that incorporate information about the ocean's observed subsurface thermal structure generally exhibit higher predictive skill than those that do not. Among models that do use subsurface temperature information, 76% predict ENSO-neutral SSTs for the Jul-Sep 2012 season, none predict La Niña conditions, and 24% predict El Niño conditions. See Note 1

Caution is advised in interpreting the distribution of model predictions as the actual probabilities. At longer leads, the skill of the models degrades, and skill uncertainty must be convolved with the uncertainties from initial conditions and differing model physics, leading to more climatological probabilities in the long-lead ENSO Outlook than might be suggested by the suite of models. Furthermore, the expected skill of one model versus another has not been established using uniform validation procedures, which may cause a difference in the true probability distribution from that taken verbatim from the raw model predictions.

An alternative way to assess the probabilities of the three possible ENSO conditions is more quantitatively precise and less vulnerable to sampling errors than the categorical tallying method used above. This alternative method uses the mean of the predictions of all models on the plume, equally weighted, and constructs a standard error function centered on that mean. The standard error is Gaussian in shape, and has its width determined by an estimate of overall expected model skill for the season of the year and the lead time. Higher skill results in a relatively narrower error distribution, while low skill results in an error distribution with width approaching that of the historical observed distribution. This method shows probabilities for La Niña at 26% for Mar-May, decreasing to 17% for Apr-Jun, 13% for May-Jul, and down to 11% by Jun-Aug. Model probabilities for ENSO-neutral conditions are 74% for Mar-May, rising to 78% by Apr-Jun and 67% for May-Jul. Probabilities for El Niño are near 0% for Mar-May, 5% for Apr-Jun, 20% for May-Jul, and 32% by Jun-Aug. A plot of the probabilities generated from this most recent IRI/CPC ENSO prediction plume using the multi-model mean and the Gaussian standard error method summarizes the model consensus out to about 10 months into the future. The same cautions mentioned above for the distributional count of model predictions apply to this Gaussian standard error method of inferring probabilities, due to differing model biases and skills. In particular, this approach considers only the mean of the predictions, and not the total range across the models, nor the ensemble range within individual models.

The probabilities derived from the more than 20 models on the IRI/CPC plume describe, on average, a dissipation of the La Niña during the March-April period of 2012, with highest liklihood of dissipation near the end of March or beginning of April. Past experience has shown that some models are biased in the direction of prolonging ENSO episodes for somewhat too long a period at the end of the typical ENSO cycle. The current model predictions do not appear to be materially affected by this bias, as most of them show neutral ENSO conditions (even if still slightly below average) for March-May, when current conditions in mid-March are still indicative of weak La Niña conditions. Thus, most of the models are indicating imminent dissipation. Currently, for the second half of the year, neutral ENSO appears most likely, and development of El Niño has a higher predicted likelihood than a return to La Niña. However, factors such as known specific model biases and recent changes that the models may have missed will be taken into account in the official outlook, which includes human judgement in combination with the model guidance, generated by CPC and IRI and to be issued at the beginning of April.

http://portal.iri.columbia.edu/portal/s ... 2&userID=2






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[NDG]

I am still not too convinced that we will see an El Nino by Jul/Aug/Sept timeframe.
ENSO predicting models are not the greatest looking past a 2-3 month forecast. Remember last year, the majority of them were showing neutral conditions for the heart of the season about the same time of the year as now.

[jinftl]

Between the mid-March and early-March forecast probabilities, we have seen the probability of enso neutral condtions rise significantly in the Aug-Sept-Oct and Sept-Oct-Nov time frames, while the probability of both la nina and el nino has fallen some...

Mid-March forecast probabilities with change from early-March probabilities in ():
A-S-O
Neutral: 54% (+9%)
El Nino: 34% (-2%)
La Nina: 12% (-7%)

A-S-O
Neutral: 54% (+13%)
El Nino: 34% (-5%)
La Nina: 12% (-8%)
http://iri.columbia.edu/climate/ENSO/cu ... gure3.html

[cycloneye]

Climate Prediction Center 3/19/12 Weekly Update

Nino 3.4 remains like on last week's update at -0.6C and the other areas remained almost the same,so in other words is status quo for now.

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf

[cycloneye]

The 30 day SOI index continues to rise,now almost at +7,meaning El Nino if it wants to show it's head,it wont be anytime soon.

[cycloneye]

The March update by ECMWF continues to forecast El Nino by June or July and CSU is following bigtime the Euro to forecast a slow 2012 Atlantic Hurricane season.

Hey peeps,I am feeling alone posting in this and in other threads at Talking Tropics forum. Come and join the discussions as the EPAC and Atlantic hurricane seasons are fast approaching and also the numbers poll

[wxman57]

You're not alone, Luis. I just saw the new Euro Nino 3.4 area forecast. I've been talking to Phil Klotzbach about the prospect of an El Nino and higher pressures across the Atlantic this season. It's looking like we may see considerably fewer named storms than 2010/2011. Of course, that doesn't rule out a major impact but it does probably make multiple major impacts less likely (from different storms).

[hurricanetrack]

So what about the IRI/CPC info a few posts up? It seems that ENSO neutral is more likely, if even only by a little bit, than an El Nino. And, it would seem that if we hit El Nino thresholds by August that it would be quite weak, perhaps just at .50 C above normal. But this is based almost entirely on the ECMWF being right, yes? If it is not right, then all of this El Nino talk could be for nothing. Only one way to find out I suppose........we'll see what it looks like on August 1

[cycloneye]

So what about the IRI/CPC info a few posts up? It seems that ENSO neutral is more likely, if even only by a little bit, than an El Nino. And, it would seem that if we hit El Nino thresholds by August that it would be quite weak, perhaps just at .50 C above normal. But this is based almost entirely on the ECMWF being right, yes? If it is not right, then all of this El Nino talk could be for nothing. Only one way to find out I suppose........we'll see what it looks like on August 1

And the SOI keeps rising and that reinforces you thinking. (See four posts above)

[tolakram]

The models haven't had a very good track record this year, in my un-professional opinion. The Euro missed Europe's cold outbreak and the GFS has been calling for colder weather in North America in 3 weeks all winter. Something is different, not sure what, and perhaps the poor short term performance is not effecting long term performance, but I just don't think we really know what this summer will be like yet.

Study from way back in 2005: http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3420.1

The European Centre for Medium-Range Weather Forecasts (ECMWF) has made seasonal forecasts
since 1997 with ensembles of a coupled ocean–atmosphere model, System-1 (S1). In January 2002, a new
version, System-2 (S2), was introduced. For the calibration of these models, hindcasts have been performed
starting in 1987, so that 15 yr of hindcasts and forecasts are now available for verification.
Seasonal predictability is to a large extent due to the El Niño–Southern Oscillation (ENSO) climate
oscillations. ENSO predictions of the ECMWF models are compared with those of statistical models, some
of which are used operationally. The relative skill depends strongly on the season. The dynamical models
are better at forecasting the onset of El Niño or La Niña in boreal spring to summer. The statistical models
are comparable at predicting the evolution of an event in boreal fall and winter.

So we are in spring now, but NA is also experiencing some of the strangest weather in our history. I wonder if any of this will effect the accuracy of the forecast?

[Ntxw]

I would not be too hung up on the daily SOI values. There's an MJO wave happening and it can effect air pressures between the two regions (Tahiti-Darwin). March isn't usually a good indicator month for ENSO forecasting regarding SOI as it's a transition period for the northern and southern hemisphere and water temps. Give it until April/May for adjusting and settle down then we'll have a good idea from the models. I'm seeing warmer temps creeping up in the southern parts of the defined enso regions and subsurface temps are rising as well.

Edit: Euro does look very aggressive, I doubt it will happen that fast.

[cycloneye]

The Euro is not alone with El Nino by June-July as CFSv2 also goes that way,although not as agressive in terms of being moderate El Nino as Euro has.

[hurricanetrack]

Yeah, the weather has been so completely out of whack as of late that nothing would shock me at this point. We will just have to wait and see and be ready. If we look at 2004, that was a weak El Nino year late in the season and there was really just that one period of 6 weeks that everything came at us. Yet, look how bad that was. All it takes is for something like that to set up, and it did it again in 2008 for a period of time, and a lot of people can be affected. No way to predict THAT this far out or even a few weeks out. One thing is for sure- June 1 is approaching and it will be time to start watching very closely.

[Kingarabian]

The Euro is being reallllly bold right now with that prediction.