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ENSO Forecast Discussion

ENSO and SST Model Forecasts

Canonical Correlation Model
Nino 3.4 Region: Historical  F1
Nino 3.4 Region: 0-4 Season  F2

NCEP Coupled Model
Eq. Pac. SST & Anomalies  F3
Nino 3 & Nino 3.4 Region  F4

NCEP Markov Model
Eq. Pac. SST & Anomalies  F5
Nino 3.4 Region  F6

LDEO Model
Eq. Pac. SST & Wind Stress Anoms  F7
Nino 3 Region  F8

Linear Inverse Modeling
Global Tropical SST Anomalies  F9
Nino 3.4 Region: Historical  F10

Scripps/MPI Hybrid Coupled Model
Eq. Pac. SST & Anomalies  F11

ENSO-CLIPER Model
All Nino Regions & SOI  F12

IRI Compilation of Forecasts
Nino3.4 Region  F13

Forecast Forum

FEBRUARY 2011

The CPC and the contributors to the Forecast Forum caution potential users of this predictive information that they can expect only modest skill.

ENSO Alert System Status: La Niña Advisory      

Outlook:  

            ENSO-Neutral  conditions are expected by June 2011.

Discussion:    

La Niña continued to weaken during February 2011 as reflected by the reduced strength of the negative surface and near-surface temperature anomalies across much of the equatorial Pacific Ocean (Figs. T9 and T15).  The Niño indices were between 0.1°C and –1.3°C for the month of February (Table T2).  Subsurface oceanic heat content anomalies (average temperatures in the upper 300m of the ocean) returned to near zero in response to the eastward progression of a strong oceanic Kelvin wave, which has weakened the negative temperature anomalies at depth in the central and eastern equatorial Pacific (Fig. T17).  La Niña continued to be most evident in the atmospheric circulation over the equatorial Pacific, although at lesser intensity.  Convection remained enhanced over much of Indonesia and suppressed over the western and central equatorial Pacific (Fig. T25).  Also, anomalous low-level easterly and upper-level westerly winds have persisted in this region (Figs. T20, T21).  However, a reduction in the strength of the anomalous low-level cross-equatorial flow, and associated oceanic upwelling, over the eastern Pacific contributed to anomalous SST warming in that region.  Collectively, these oceanic and atmospheric anomalies reflect a weakening La Niña. 

In concurrence with the observed evolution, nearly all of the ENSO models predict La Niña to weaken further in the coming months (Figs. F1-F13).  While the majority of models predict a return to ENSO-neutral by May-June-July 2011 (three month average in the Nino-3.4 index between –0.5°C and +0.5°C), there continues to be large uncertainty in the status of ENSO through the Northern Hemisphere summer and fall.  Due to both model and observed trends, there is increasing confidence in ENSO-neutral conditions by June 2011.  However, model forecasts issued in the spring typically have minimum skill (the “spring barrier”), which results in low confidence forecasts for summer and beyond. 

Weekly updates of oceanic and atmospheric conditions are available on the Climate Prediction Center homepage (El Niño/La Niña Current Conditions and Expert Discussions).