ENSO Updates Thread

The sst anomalies are warm in Nino 3.4 and in fact on almost all the equatorial Pacific but the question is if they will stay that way in the next few months or cooling will occur.IMO,we are close to a El Nino official declaration by Climate Prediction Center.Stay tuned to this thread as all the information about how ENSO is doing will be posted.

Here is the update by CPC of ENSO and it has Nino 3.4 going up to +1.0C.

www.cpc.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

CPC made a great discussion blog about why they didn't declared officially El Nino.

www.climate.gov/news-features/blogs/enso/decembers-enso-update-close-no-cigar 

CPC weekly update has Nino 3.4 up to +0.9C.

www.cpc.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Climate Prediction Center 12/18/14 update.

They say a moderate El Nino is not ruled out and there are still some things that are not El Nino-like.Read the whole update below along with the new updated graphic that has the plume of models.

Recent and Current Conditions

The SST anomaly in the NINO3.4 region has been at the weak El Niño level from mid-October to the present, and even reached the borderline of moderate El Niño for a single week at the end of November. For November the average NINO3.4 SST anomaly was 0.85 C, indicative of weak Niño conditions, and for Aug-Oct it was 0.60 C. The IRI’s definition of El Niño, like NOAA/Climate Prediction Center’s, requires that the SST anomaly in the Nino3.4 region (5S-5N; 170W-120W) exceed 0.5 C. Similarly, for La Niña, the anomaly must be -0.5 C or less. The climatological probabilities for La Niña, neutral, and El Niño conditions vary seasonally, and are shown in a table at the bottom of this page for each 3-month season. The most recent weekly SST anomaly in the Nino3.4 region was 0.9 C, in the category of weak El Niño for SST. However, accompanying this SST is an atmospheric pattern with inadequate indication of an El Niño-like pattern–very weak westerly low-level wind anomalies and no positive anomalies of convection near the dateline. Some indicators, however, such as the Southern Oscillation Index (SOI), have been somewhat indicative of weak El Niño, and the upper level wind anomalies are also showing El Niño-indicative enhanced easterlies.

Expected Conditions

What is the outlook for the ENSO status going forward? The most recent official diagnosis and outlook was issued earlier this month in the NOAA/Climate Prediction Center ENSO Diagnostic Discussion, produced jointly by CPC and IRI; it called for a 66% likelihood for El Niño conditions during the Nov-Jan season now in progress, remaining at 60% or more through Jan-Mar 2015. The latest set of model ENSO predictions, from mid-December, now available in the IRI/CPC ENSO prediction plume, is discussed below. Currently, Nino3.4 SST anomalies are about 0.9C, above the 0.5C threshold for weak El Niño. Subsurface temperature anomalies across the eastern equatorial Pacific have remained above average. In the atmosphere, the basin-wide sea level pressure pattern (e.g. the SOI) has been near the threshold of -0.8 to -0.10 for a weak El Niño in late November and early December, but recently weakened back toward neutral levels. Also, other atmospheric parameters continue to reflect neutral ENSO conditions: Weak anomalous low-level westerlies have only appeared at times during November and early December. Upper level anomalous easterly anomalies are being observed over substantial portions of the equatorial Pacific, indicative of El Niño. On the other hand, anomalous convection (as measured by OLR) has been near average, or even below average, near and eastward of the dateline. Together, the oceanic and atmospheric features currently reflect a warmish but neutral ENSO condition, despite the clearly weak El Niño status of the SST during the last one to two months.

As of mid-December, none of the dynamical or statistical models models predicts La Niña SST conditions for the initial Dec-Feb 2014-15 season, 96% predicts El Niño conditions, and 4% indicates neutral ENSO. At lead times of 3 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. For the Mar-May 2015 season, among models that do use subsurface temperature information, 20% predicts ENSO-neutral SSTs, 80% predicts El Niño conditions and none predicts La Niña conditions. For all model types, the probability for neutral ENSO conditions is 32% or below between Dec-Feb 2014-15 through Apr-Jun 2015, and 50% or below through Jul-Sep. Probabilities for El Niño are 84% or higher between Dec-Feb 2014-15 and Jan-Mar, and at least 70% out to Apr-Jun 2015. No model predicts La Niña conditions for any of the 3-month periods between Dec-Feb 2014-15 and Aug-Oct 2015.

Note - Only models that produce a new ENSO prediction every month are included in the above statement.

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 near 0% from Dec-Feb 2014-15 through Apr-Jun 2015, rising to 5% by Jun-Aug and 14% by Aug-Oct. Model probabilities for neutral ENSO conditions are 17% for the initial period of Dec-Feb 2014-15, 24% for the next running period of Jan-Mar 2015, and rise to 39% by Apr-Jun, and to 40-45% for May-Jul through Aug-Oct. Probabilities for El Niño are 83% for Dec-Feb 2014-15, 76% for Jan-Mar 2015, 70% for Feb-Apr, and do not fall below 50% until Aug-Oct when they are 46%. The models collectively favor El Niño over other ENSO conditions by a sizable margin until Apr-Jun 2015. 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 models on the IRI/CPC plume describe, on average, El Niño conditions for the Dec-Feb 2014-15 season currently in progress, enduring well into northern spring season of 2015. The consensus of model predictions calls for a weak El Niño event, although a moderate event cannot be ruled out. A strong event appears virtually impossible. A caution regarding this latest set of model-based ENSO plume predictions, is that factors such as known specific model biases and recent changes that the models may have missed will be taken into account in the next official outlook to be generated and issued in early October by CPC and IRI, which will include some human judgement in combination with the model guidance.

iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-iri_update

CPC in it's 12/29/14 update has Nino 3.4 down to +0.7C and has Nino 1+2 down to -0.2C. Maybe a Modoki El Nino in the works here?

www.cpc.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

CPC diagnostic monthly update has Weak El Nino for the next 2 months and then Neutral returns. Wow,that is a very brief El Nino episode. What implications down the road it will have on the sever weather season and the North Atlantic Hurricane Season is still early to tell.

EL NIÑO/SOUTHERN OSCILLATION (ENSO)
DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP/NWS
and the International Research Institute for Climate and Society
8 January 2015


ENSO Alert System Status: El Niño Watch



Synopsis: There is an approximately 50-60% chance of El Niño conditions during the next two months, with ENSO-neutral favored thereafter.

During December 2014, positive sea surface temperature (SST) anomalies decreased across the central and east-central equatorial Pacific (Fig. 1). At the end of the month, the weekly Niño indices ranged from +0.8oC in the Niño-4 region, to +0.5oC in the Niño-3.4 region, to 0.0oC in the Niño-1+2 region (Fig. 2). The positive subsurface heat content anomalies (averaged between 180o-100oW) also decreased during December (Fig. 3) in response to an upwelling equatorial oceanic Kelvin wave (Fig. 4). Although the surface and sub-surface temperature anomalies were consistent with El Niño, the overall atmospheric circulation continued to show only limited coupling with the anomalously warm water. The equatorial low-level winds were largely near average during the month, while upper-level easterly anomalies continued in the central and eastern tropical Pacific. The Southern Oscillation Index (SOI) remained slightly negative, but the Equatorial SOI remained near zero. Also, rainfall remained below-average near the Date Line and was above-average over Indonesia (Fig. 5). Overall, the combined atmospheric and oceanic state remains ENSO-neutral.

Similar to last month, most models predict the SST anomalies to remain at weak El Niño levels (3-month values of the Niño-3.4 index between 0.5oC and 0.9oC) during December-February 2014-15, and lasting into the Northern Hemisphere spring 2015 (Fig. 6). If El Niño were to emerge, the forecaster consensus favors a weak event that ends in early Northern Hemisphere spring. In summary, there is an approximately 50-60% chance of El Niño conditions during the next two months, with ENSO-neutral favored thereafter (click CPC/IRI consensus forecast for the chance of each outcome).

iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-cpc_update