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ENSO Forecasts

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IRI ENSO Forecast

2014 June Quick Look

Published: June 19, 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 on the right to navigate to the different forecast sections

During May through mid-June the observed ENSO conditions remained near the borderline of a weak El Niño condition in the ocean, but the atmosphere so far has shown little involvement. Most of the ENSO prediction models indicate more warming coming in the months ahead, leading to sustained El Niño conditions by the middle of northern summer.

Figures 1 and 3 (the official ENSO probability forecast and the objective model-based ENSO probability forecast, respectively) are often quite similar. However, occasionally they may differ noticeably. There can be several reasons for differences. One possible reason is that the human forecasters, using their experience and judgment, may disagree to some degree with the models, which may have known biases. Another reason is related to the fact that the models are not run at the same time that the forecasters make their assessment, so that the starting ENSO conditions may be slightly different between the two times. The charts on this Quick Look page are updated at two different times of the month, so that between the second and the third Thursday of the month, the official forecast (Fig. 1) has just been updated, while the model-based forecasts (Figs. 3 and 4) are still from the third Thursday of the previous month. On the other hand, from the third Thursday of the month until the second Thursday of the next month, the model-based forecasts are more recently updated, while the official forecasts remain from the second Thursday of the current month.
Click on the for more information on each figure.

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 October - February
  • Typically persist for 9-12 months, though occasionally persisting for up to 2 years
  • Typically recur every 2 to 7 years

IRI ENSO Forecast

CPC/IRI ENSO Update

Published: June 5, 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: The chance of El Niño is 70% during the Northern Hemisphere summer and reaches 80% during the fall and winter

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 are also updated monthly in the Forecast Forum section of CPC’s Climate Diagnostics Bulletin. Additional perspectives and analysis are also available in an ENSO blog.  

The next ENSO Diagnostics Discussion is scheduled for 10 July 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
MJJ 2014 ~0% 39% 61%
JJA 2014 1% 30% 69%
JAS 2014 1% 26% 73%
ASO 2014 1% 22% 77%
SON 2014 1% 19% 80%
OND 2014 1% 17% 82%
NDJ 2014 1% 17% 82%
DJF 2014 2% 18% 80%
JFM 2015 2% 22% 76%

Please refer to our licensing agreement for permission to use IRI ENSO materials. The CPC/IRI materials are not included in this licensing.

IRI ENSO Forecast

IRI Technical ENSO Update

Published: June 19, 2014

Recent and Current Conditions

The SST anomaly in the Nino3.4 region in recent weeks has been near the borderline of neutral and El Nino during the mid-May to mid-June period, 2014. For May the Nino3.4 SST anomaly was 0.45 C, indicative of neutral conditions but very close to the borderline of El Nino, and for Mar-May it was 0.16 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 0.4 C, which is about the same as the 0.45 C observed in May, close to the borderline of an El Niño condition if it were to persist. The trend is an upward one for Mar-May to May. However, although the SST has been near the borderline of weak El Niño conditions, the atmospheric participation in an El Niño-like pattern has been absent to very weak at best.

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 a transition from neutral ENSO conditions to El Niño conditions during summer 2014, with probabilities of El Niño rising to 70% by Jun-Aug 2014, and to approximately 80% by northern autumn 2014. The latest set of model ENSO predictions, from mid-June, now available in the IRI/CPC ENSO prediction plume, is discussed below. Currently, Nino3.4 SST anomalies are near the borderline of neutral and weak El Niño, and have been that way for several weeks. Positive anomalies maximize near the dateline and also in the far eastern part of the Pacific basin, with relatively weaker anomalies in between where the Nino3.4 region is located.  Subsurface temperature anomalies across the eastern equatorial Pacific are 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. These anomalies at depth have been surfacing in the far eastern part of the basin, so that the integrated heat content has been slowly declining over the last couple of months. In the atmosphere, the basin-wide sea level pressure pattern (e.g. the SOI) has been close to average recently. The low-level zonal winds and the upper level winds have also been close to average in recent weeks. Anomalous convection (as measured by OLR) has been positive somewhat to the west of the dateline, but near average near and east of the dateline.  These atmospheric conditions are not suggestive of El Niño despite the SST being near the borderline of El Niño. Together, the oceanic and atmospheric features continue to reflect neutral ENSO conditions that lean toward the borderline of weak El Niño. The ocean-atmosphere coupling needs to appear as the onset of El Niño conditions likely gets underway over the course of the coming northern summer season.

As of mid-June, none of the dynamical or statistical models models predicts La Niña SST conditions for the Jun-Aug 2014 season, 71% predicts El Niño conditions, and 29% indicates neutral ENSO for the initial Jun-Aug 2014 period. 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 Sep-Nov 2014 season, among models that do use subsurface temperature information, 10% predicts ENSO-neutral SSTs, 90% predicts El Niño conditions and none predicts La Niña conditions. For all model types, the probability for neutral ENSO conditions is below 25% between Aug-Oct 2014 and Jan-Mar 2015, being between 30% and 39% during Jun-Aug and Jul-Sep, and again at the end of the forecast period in Feb-Apr 2015. Probabilities for El Niño rise to more than 75% during the very same times, Aug-Oct 2014 to Jan-Mar 2015. Probabilities for El Niño fall to about 60% by Feb-Apr 2015.  No model predicts La Niña conditions for any of the 3-month periods between Jun-Aug 2014 and Feb-Apr 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 no higher than 1% for any period between Jun-Aug 2014 through Feb-Apr 2015.  Model probabilities for neutral ENSO conditions are 39% for the initial period of Jun-Aug 2014, 35% for the next running period of Jul-Sep, and the hover between 22% and 30% through the northern summer and fall 2014, rising again to 32% for Dec-Feb 2014-15 and to 42% for Feb-Apr 2015. Probabilities for El Niño are 61% for Jun-Aug 2014, rise to near 65% for Jul-Sep, 69% for Aug-Oct, and to 78% for Oct-Dec 2014 and Nov-Jan 2014-15. The models collectively favor El Niño over other ENSO conditions by a clear margin between Jun-Aug 2014 and Jan-Mar 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, a likely development of El Niño development during Jun-Aug 2014, as the objective model-based probabilities for El Niño exceed those for neutral ENSO by more than a small margin between that season and Jan-Mar 2015. The consensus of model predictions calls for a weak to moderate El Niño event. 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/CPC Mid-Month Plume-Based ENSO Forecast Probabilities

Season La Niña Neutral El Niño
JJA 2014 ~0% 39% 61%
JAS 2014 ~0% 35% 65%
ASO 2014 1% 30% 69%
SON 2014 ~0% 26% 74%
OND 2014 ~0% 22% 78%
NDJ 2014 ~0% 22% 78%
DJF 2014 ~0% 26% 74%
JFM 2015 1% 32% 67%
FMA 2015 1% 42% 57%

Please refer to our licensing agreement for permission to use IRI ENSO materials. The CPC/IRI materials are not included in this licensing.

IRI ENSO Forecast

IRI/CPC Model-Based Probabilistic ENSO Forecast

Published: June 19, 2014

A purely objective ENSO probability forecast, based on regression, using as input the model predictions from the plume of dynamical and statistical forecasts shown in the ENSO Predictions Plume. Each of the forecasts is weighted equally. It is updated near or just after the middle of the month, using forecasts from the plume models that are run in the first half of the month. It does not use any human interpretation or judgment. This is updated on the third Thursday of the month.



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

Season La Niña Neutral El Niño
JJA 2014 ~0% 39% 61%
JAS 2014 ~0% 35% 65%
ASO 2014 1% 30% 69%
SON 2014 ~0% 26% 74%
OND 2014 ~0% 22% 78%
NDJ 2014 ~0% 22% 78%
DJF 2014 ~0% 26% 74%
JFM 2015 1% 32% 67%
FMA 2015 1% 42% 57%

IRI ENSO Forecast

CPC/IRI Official Probabilistic ENSO Forecast

Published: June 5, 2014

The official CPC/IRI ENSO probability forecast, based on a consensus of CPC and IRI forecasters. It is updated during the first half of the month, in association with the official CPC/IRI ENSO Diagnostic Discussion. It is based on observational and predictive information from early in the month and from the previous month. It uses human judgment in addition to model output, while the forecast shown in the Model-Based Probabilistic ENSO Forecast relies solely on model output. This is updated on the second Thursday of every month.



CPC/IRI Early-Month Consensus ENSO Forecast Probabilities

Season La Niña Neutral El Niño
MJJ 2014 ~0% 39% 61%
JJA 2014 1% 30% 69%
JAS 2014 1% 26% 73%
ASO 2014 1% 22% 77%
SON 2014 1% 19% 80%
OND 2014 1% 17% 82%
NDJ 2014 1% 17% 82%
DJF 2014 2% 18% 80%
JFM 2015 2% 22% 76%

Please refer to our licensing agreement for permission to use IRI ENSO materials. The CPC/IRI materials are not included in this licensing.

IRI ENSO Forecast

IRI/CPC ENSO Predictions Plume

Published: June 19, 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.


Because of occasional data corrections and late model runs following the time of ENSO product issuance, the data shown in the ENSO forecast table and the ENSO plume graph may not always match. The best source of the ENSO forecast data is http://iri.columbia.edu/~forecast/ensofcst/Data/ensofcst_ALLtoMMYY where MM is the month number and YY is the year.


Seasons (2014-2015)
Model JJA JAS ASO SON OND NDJ DJF JFM FMA
Dynamical models
NCEP CFS version 2 0.4 0.5 0.7 0.9 0.9 0.9 0.8 0.8
NASA GMAO model 0.7 0.8 0.9 1.1 1.2 1.2 1.2
Japan Met. Agency model 0.6 0.6 0.7 0.9 1.1
Scripps Inst. HCM 0.8 0.9 1 1.1 1.2 1.3 1.3 1.2 1.1
Lamont-Doherty model 0.5 0.4 0.5 0.6 0.5 0.4 0.2 0.2 0.2
POAMA (Austr) model 0.3 0.2 0.2 0.2 0.2 0.2 0.3
ECMWF model 0.6 0.8 1 1.2 1.3
UKMO model 0.5 0.5 0.5 0.6
KMA (Korea) SNU model 0.8 1 1.2 1.2 1.2 1.1 1.1 1 0.9
ESSIC Intermed. Coupled model 0.7 0.7 0.7 0.7 0.8 0.9 0.8 0.7 0.5
COLA CCSM3 model 0.9 1 1 1.1 1.2 1.2 1 0.7 0.1
MÉTÉO FRANCE model 0.7 0.8 0.9 0.9 0.8
Japan Frontier Coupled model 0.8 1 1.1 1 0.9 0.9 0.9 0.9 0.9
CSIR-IRI 3-model MME 0.6 0.7 0.8 0.9 1.1 1.3
GFDL CM2.1 Coupled Climate model 0.4 0.4 0.5 0.5 0.5 0.5 0.6 0.6 0.6
Canadian Coupled Fcst Sys 0.9 1.1 1.2 1.2 1.2 1.2 1.2 1.1 1
GFDL CM2.5 FLOR Coupled Climate model 0.7 0.9 1 1 1 1.1 1.1 1.1 1.1
Average, dynamical models 0.6 0.7 0.8 0.9 0.9 0.9 0.9 0.8 0.7
Statistical models
NCEP/CPC Markov model 0.4 0.5 0.6 0.7 0.8 0.9 1 0.9 0.8
NOAA/CDC Linear Inverse 0.1 0 0 -0.1 -0.1 -0.1 -0.1 0 0
NCEP/CPC Constructed Analog 0.5 0.5 0.5 0.6 0.8 0.9 0.8 0.7 0.5
NCEP/CPC Can Cor Anal 0.5 0.5 0.6 0.7 0.8 0.8 0.6 0.5 0.4
Landsea/Knaff CLIPER 0.9 1.1 1.3 1.4 1.4 1.4 1.4 1.1 0.8
Univ. BC Neural Network 0.4 0.3 0.4 0.4 0.4 0.5 0.6 0.6 0.6
FSU Regression 0.7 0.7 0.8 1 1.2 1.3 1.2 0.9 0.7
TCD – UCLA 1 1.2 1.3 1.4 1.4 1.3 1 0.7 0.4
UNB/CWC Nonlinear PCA 0.5 0.5 0.4 0.3 0.2 0.1 0 0 -0.1
Average, statistical models 0.6 0.6 0.6 0.7 0.8 0.8 0.7 0.6 0.5
Average, all models 0.6 0.7 0.8 0.8 0.9 0.9 0.8 0.7 0.6

Discussion of Current Forecasts

Most of the set of dynamical and statistical model predictions issued during late May and early June 2014 predict a transition from borderline El Nino conditions to weak El Nino conditions from early northern summer 2014 into mid-summer, with a steady warming predicted through summer and continuing into fall 2014. Development of El Nino conditions appears approximately 60-65% likely for the Jun-Aug season of 2014, and rises to near 80% by Oct-Dec. In the most recent week, the SST anomaly in the Nino3.4 region was 0.4C, reflecting nearly borderline neutral/El Nino conditions. The weekly SSTs have hovered close to 0.5 for the last several weeks. 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
JJA 2014 ~0% 39% 61%
JAS 2014 ~0% 35% 65%
ASO 2014 1% 30% 69%
SON 2014 ~0% 26% 74%
OND 2014 ~0% 22% 78%
NDJ 2014 ~0% 22% 78%
DJF 2014 ~0% 26% 74%
JFM 2015 1% 32% 67%
FMA 2015 1% 42% 57%

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.

Please refer to our licensing agreement for permission to use IRI ENSO materials. The CPC/IRI materials are not included in this licensing.