ENSO Forecast Navigation

Download the Quicklook PDF

ENSO Forecasts

IRI ENSO Forecast

2014 April Quick Look

Published: April 17, 2014

A monthly summary of the status of El Niño, La Niña, and the Southern Oscillation, or ENSO, based on the NINO3.4 index (120-170W, 5S-5N)

Use the navigation menu to navigate to the different forecast sections

During March through mid-April the observed ENSO conditions moved from cool-neutral to warm-neutral. All of the ENSO prediction models indicate a warming trend, with neutral ENSO during northern spring 2014 transitioning to El Niño conditions by the middle of northern summer.

Historically Speaking

    El Niño and La Niña events tend to develop during the period Apr-Jun and they
  • Tend to reach their maximum strength during Dec-Feb
  • Typically persist for 9-12 months, though occasionally persisting for up to 2 years
  • Typically recur every 2 to 7 years

Figure 1 is based on a consensus of CPC and IRI forecasters, in association with the official CPC/IRI ENSO Diagnostic Discussion

Figure 3 is purely objective, based on regression, using equally weighted model predictions from the plume

IRI ENSO Forecast

CPC/IRI ENSO Update

Published: April 10, 2014

El Niño/Southern Oscillation (ENSO) Diagnostic Discussion issued jointly by the Climate Prediction Center/NCEP/NWS and the International Research Institute for Climate and Society

ENSO Alert System Status: El Niño Watch

Synopsis: While ENSO-neutral is favored for Northern Hemisphere spring, the chances of El Niño increase during the remainder of the year, exceeding 50% by summer.

ENSO-neutral continued during March 2014, but with above-average sea surface temperatures (SST) developing over much of the eastern tropical Pacific as well as near the International Date Line (Figure 1). The weekly SSTs were below average in the Niño1+2 region, near average but rising in Niño3 and Niño3.4 regions, and above average in the Niño4 region (Figure 2). A significant downwelling oceanic Kelvin wave that was initiated in January greatly increased the oceanic heat content to the largest March value in the historical record back to 1979 (Figure 3) and produced large positive subsurface temperature anomalies across the central and eastern Pacific (Figure 4). Also during March, low-level westerly wind anomalies were observed over the central equatorial Pacific. Convection was suppressed over western Indonesia, and enhanced over the central equatorial Pacific (Figure 5). Although these atmospheric and oceanic conditions collectively reflect ENSO-neutral, they also reflect a clear evolution toward an El Niño state.

The model predictions of ENSO for this summer and beyond are indicating an increased likelihood of El Niño this year compared with last month. Most of the models indicate that ENSO-neutral (Niño-3.4 index between -0.5°C and 0.5°C) will persist through much of the remainder of the Northern Hemisphere spring 2014 (Figure 6), with many models predicting the development of El Niño sometime during the summer or fall. Despite this greater model consensus, there remains considerable uncertainty as to when El Niño will develop and how strong it may become. This uncertainty is amplified by the inherently lower forecast skill of the models for forecasts made in the spring. While ENSO-neutral is favored for Northern Hemisphere spring, the chances of El Niño increase during the remainder of the year, and exceed 50% by the summer (click CPC/IRI consensus forecast for the chance of each outcome).

This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA’s National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts for the evolution of El Niño/La Niña are updated monthly in the Forecast Forum section of CPC’s Climate Diagnostics Bulletin. The next ENSO Diagnostics Discussion is scheduled for 10 April 2014. To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: ncep.list.enso-update@noaa.gov.

CPC/IRI Early-Month Consensus ENSO Forecast Probabilities

Season La Niña Neutral El Niño
MAM 2014 1% 79% 20%
AMJ 2014 1% 64% 35%
MJJ 2014 2% 53% 45%
JJA 2014 2% 46% 52%
JAS 2014 3% 41% 56%
ASO 2014 3% 36% 61%
SON 2014 3% 34% 63%
OND 2014 4% 32% 64%
NDJ 2014 4% 30% 66%

IRI ENSO Forecast

IRI Technical ENSO Update

Published: April 17, 2014

Recent and Current Conditions

The SST anomaly in the Nino3.4 region in recent weeks has been in the neutral range but rising during the mid-March to mid-April period, 2014. For March the Nino3.4 SST anomaly was -0.22 C, indicative of neutral conditions, and for Jan-Mar it was -0.43 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 0.2 C, which is warmer than the -0.22 C observed in March. The trend is then an upward one both for Jan-Mar to March, and from March to last week’s observation.

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 likelihood for neutral ENSO conditions continuing into spring 2014, but with probabilities of El Niño rising to 52% by Jun-Aug 2014, and to 66% by early northern winter 2014-15. The latest set of model ENSO predictions, from mid-April, now available in the IRI/CPC ENSO prediction plume, is discussed below. Currently, Nino3.4 SST anomalies are in the warm-neutral range. Anomalies are positive near the dateline and also in the portion of the eastern tropical Pacific in part of the Nino3 region (5S-5N; 90W-150W). Subsurface temperature anomalies across the central and eastern equatorial Pacific have increased to become very strongly above average levels, due to a downwelling Kelvin wave triggered by two westerly wind events in the western tropical Pacific during the Jan-Mar period. In the atmosphere, the basin-wide sea level pressure pattern (e.g. the SOI) has been close to average recently, with a hint of becoming slightly negative. The low-level zonal winds have been weak, and the upper level winds have also shown no strong or spatially extensive anomalies. Anomalous convection (as measured by OLR) has become positive near the dateline, and near average in much of the remainder of the equatorial Pacific basin. Together, these features continue to reflect ENSO-neutral conditions. The much above average subsurface heat content, however, has the potential to raise the SST farther in the eastern part of the basin in the very near future. This, in turn, could induce anaomlous low level westerlies in the central and eastern part of the equatorial Pacific, which could lead to a coupling of ocean and atmosphere in such a way as to induce the onset of El Niño conditions.

As of mid-April, none of the dynamical or statistical models models predicts La Niña SST conditions for the Apr-Jun 2014 season, 14% predicts El Niño conditions, and 86% 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 Jul-Sep 2014 season, among models that do use subsurface temperature information, 12% predicts ENSO-neutral SSTs, 88% predicts El Niño conditions and none predicts La Niña conditions. For all model types, the probability for neutral ENSO conditions is above 50% only for Apr-Jun 2014, is 29% for Jun-Aug 2014, and is mainly in the 10-30% range from Aug-Oct through Dec-Feb 2014-15 at the end of the forecast period. Probabilities for El Niño rise to 52% for May-Jul 2014, to 71% for Jun-Aug, and Jul-Sep, and settle in mainly the 80-88 range from Aug-Oct through Dec-Feb. No model predicts La Niña conditions for any of the 3-month periods between Apr-Jun and Dec-Feb.

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 at near 0% for Apr-Jun 2014, and remaining at 2% or less for all forecast periods through Dec-Feb 2004-15.  Model probabilities for neutral ENSO conditions are above 75% for Apr-Jun 2014, 49% for May-Jul, 37% for Jun-Aug, 30% for Jul-Sep, and between 20 and 25% for Aug-Oct through Dec-Feb 2014-15 at the end of the forecast period. Probabilities for El Niño are 25% for Apr-Jun 2014, rise to 49% for May-Jul, 62% for Jun-Aug, 69% for Jul-Sep, and between 74% and 80% for Aug-Oct through Dec-Feb 2014-15. It is clear that the models collectively favor neutral ENSO conditions only for Apr-Jun 2014, give about equal chances for neutral or El Niño for May-Jul, followed by the remainder of 2014 when El Niño becomes considerably more likely than neutral.  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, maintenance of neutral ENSO conditions into northern spring 2014. A good possibility for El Niño development is seen starting in May-Jul 2014, as the objective model-based probabilities for El Niño begin exceeding those for neutral ENSO through Dec-Feb 2014-15 at the end of the forecast period. The uncertainty will diminish as we progress through the northern spring predictability barrier in the coming two months. 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.

 

Climatological Probabilities
Season La Niña Neutral El Niño
DJF 37% 28% 35%
JFM 34% 37% 29%
FMA 30% 48% 22%
MAM 26% 54% 20%
AMJ 24% 54% 22%
MJJ 25% 51% 24%
JJA 25% 50% 25%
JAS 27% 46% 27%
ASO 29% 40% 31%
SON 32% 34% 34%
OND 34% 31% 35%
NDJ 37% 27% 36%

 

IRI ENSO Forecast

IRI/CPC Plume-Based Probabilistic ENSO Forecast

Published: April 17, 2014



IRI/CPC Mid-Month Plume-Based ENSO Forecast Probabilities

Season La Niña Neutral El Niño
AMJ 2014 ~0% 75% 25%
MJJ 2014 2% 50% 48%
JJA 2014 2% 37% 61%
JAS 2014 1% 31% 68%
ASO 2014 1% 25% 74%
SON 2014 1% 25% 74%
OND 2014 1% 20% 79%
NDJ 2014 1% 21% 78%
DJF 2014 1% 24% 75%

IRI ENSO Forecast

CPC/IRI Consensus Probabilistic ENSO Forecast

Published: April 10, 2014



CPC/IRI Early-Month Consensus ENSO Forecast Probabilities

Season La Niña Neutral El Niño
MAM 2014 1% 79% 20%
AMJ 2014 1% 64% 35%
MJJ 2014 2% 53% 45%
JJA 2014 2% 46% 52%
JAS 2014 3% 41% 56%
ASO 2014 3% 36% 61%
SON 2014 3% 34% 63%
OND 2014 4% 32% 64%
NDJ 2014 4% 30% 66%

IRI ENSO Forecast

IRI/CPC ENSO Predictions Plume

Published: April 17, 2014

Note on interpreting model forecasts

The following graph and table show forecasts made by dynamical and statistical models for SST in the Nino 3.4 region for nine overlapping 3-month periods. Note that the expected skills of the models, based on historical performance, are not equal to one another. The skills also generally decrease as the lead time increases. Thirdly, forecasts made at some times of the year generally have higher skill than forecasts made at other times of the year--namely, they are better when made between June and December than when they are made between February and May. Differences among the forecasts of the models reflect both differences in model design, and actual uncertainty in the forecast of the possible future SST scenario.


Seasons (2014-2014)
Model AMJ MJJ JJA JAS ASO SON OND NDJ DJF
Dynamical models
NCEP CFS version 2 0.7 1 1.1 1.1 1.3 1.5 1.5 1.4
NASA GMAO model 0.4 0.6 0.8 1 1.1 1.2 1.3
Japan Met. Agency model 0.5 0.7 0.9 1.2 1.4
Scripps Inst. HCM 0.3 0.5 0.7 0.8 1 1.1 1.2 1.2 1.2
Lamont-Doherty model 0.1 0.3 0.3 0.3 0.3 0.5 0.6 0.5 0.5
POAMA (Austr) model 0.6 0.8 1 1.2 1.3 1.4 1.5
ECMWF model 0.6 0.9 1.1 1.3 1.5
UKMO model 0.4 0.5 0.6 0.7
KMA (Korea) SNU model 0.4 0.5 0.6 0.8 0.9 1 0.9 0.9 0.9
MÉTÉO FRANCE model 0.3 0.6 0.9 1.2 1.5
CSIR-IRI 3-model MME 0.2 0.3 0.5 0.7 0.8 0.8
GFDL CM2.1 Coupled Climate model 0.5 0.8 1.2 1.3 1.3 1.3 1.3 1.3 1.2
Canadian Coupled Fcst Sys 0.3 0.5 0.7 0.8 0.9 1 1.1 1.1 1.1
Average, dynamical models 0.4 0.6 0.8 1 1.1 1.1 1.2
Statistical models
NCEP/CPC Markov model 0.2 0.2 0.3 0.4 0.5 0.7 0.8 1 1.1
NOAA/CDC Linear Inverse -0.1 0 0.1 0.1 0.1 0.1 0.2 0.2 0.2
NCEP/CPC Constructed Analog 0 0.3 0.4 0.4 0.4 0.5 0.7 0.7 0.6
NCEP/CPC Can Cor Anal 0.3 0.5 0.6 0.7 0.8 0.9 1 1 0.9
Landsea/Knaff CLIPER -0.2 -0.1 0 0.1 0.2 0.3 0.5 0.4 0.3
Univ. BC Neural Network 0 0.1 0.3 0.4 0.6 0.7 0.8 0.9 0.9
FSU Regression 0.5 0.8 1 1 1.2 1.3 1.6 1.7 1.6
TCD – UCLA 0.4 0.5 0.6 0.7 0.8 1 1 0.9 0.8
Average, statistical models 0.1 0.3 0.4 0.5 0.6 0.7 0.8 0.8 0.8
Average, all models 0.3 0.5 0.7 0.8 0.9 0.9 1 0.9 0.9

Discussion of Current Forecasts

Most of the set of dynamical and statistical model predictions issued during late March and early April 2014 predict neutral ENSO conditions into the remainder of northern spring 2014, but with a steady warming predicted during spring and into summer 2014. Development of El Nino conditions appears more than 60% likely by the Jun-Aug season of 2014. In the most recent week, the SST anomaly in the Nino3.4 region was 0.2C, reflecting warm-neutral conditions. Based on the multi-model mean predictions, and the expected skill of the models by start time and lead time, the probabilities (X100) for La Nina, neutral and El Nino conditions (using -0.5C and 0.5C thresholds) over the coming 9 seasons are:

IRI/CPC Mid-Month Plume-Based ENSO Forecast Probabilities

Season La Niña Neutral El Niño
AMJ 2014 ~0% 75% 25%
MJJ 2014 2% 50% 48%
JJA 2014 2% 37% 61%
JAS 2014 1% 31% 68%
ASO 2014 1% 25% 74%
SON 2014 1% 25% 74%
OND 2014 1% 20% 79%
NDJ 2014 1% 21% 78%
DJF 2014 1% 24% 75%

Summary of forecasts issued over last 22 months

The following plots show the model forecasts issued not only from the current month (as in the plot above), but also from the 21 months previous to this month. The observations are also shown up to the most recently completed 3-month period. The plots allow comparison of plumes from the previous start times, or examination of the forecast behavior of a given model over time. The first plot shows forecasts for dynamical models, the second for statistical models, and the third for all models. For less difficult readability, forecasts are shown to a maximum of only the first five lead times. Below the third plot, we provide a mechanism for highlighting the forecasts of one model at a time against a background of more lightly colored lines for all other models.


Notes on the data 

Only models producing forecasts on a monthly basis are included. This means that some models whose forecasts appear in the Experimental Long-Lead Forecast Bulletin (produced by COLA) do not appear in the table.

The SST anomaly forecasts are for the 3-month periods shown, and are for the Nino 3.4 region (120-170W, 5N-5S). Often, the anomalies are provided directly in a graph or a table by the respective forecasting centers for the Nino 3.4 region. In some cases, however, they are given for 1-month periods, for 3-month periods that skip some of the periods in the above table, and/or only for a region (or regions) other than Nino 3.4. In these cases, the following means are used to obtain the needed anomalies for the table:

  • Temporal averaging
  • Linear temporal interpolation
  • Visual averaging of values on a contoured map

The anomalies shown are those with respect to the base period used to define the normals, which vary among the groups producing model forecasts. They have not been adjusted to anomalies with respect to a common base period. Discrepancies among the climatological SST resulting from differing base periods may be as high as a quarter of a degree C in the worst cases. Forecasters are encouraged to use the standard 1971-2000 period as the base period, or a period not very different from it.