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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

APRIL 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 to develop during May-June 2011 and continue through the Northern Hemisphere summer 2011.

Discussion:    

During April 2011, La Niña continued to weaken as indicated by increasing surface and subsurface temperature anomalies across the equatorial Pacific Ocean (Figs. T9 and T15).  The Niño indices reflected below-average sea surface temperatures (SSTs) in the central and east-central Pacific (–0.7°C in Nino-4 and –0.8°C in Nino-3.4 regions), and near-average to above-average SSTs in the eastern Pacific (–0.3°C in Nino-3 and +0.2°C in Nino-1+2 regions; Fig. T18 and Table T2).  The subsurface oceanic heat content anomalies (average temperatures in the upper 300m of the ocean) increased slightly, due to an expanded area of above-average temperatures at thermocline depth (Fig. T17).  Consistent with other transitions to ENSO-neutral conditions, the atmospheric circulation anomalies related to La Niña remained considerable over the tropical and subtropical Pacific.  Convection was 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 and T21).  Collectively, these oceanic and atmospheric anomalies reflect a weakening La Niña, but with ongoing global impacts. 

Current observed trends, along with forecasts from nearly all of the ENSO models, indicate La Niña will continue to weaken in the coming months, with a return to ENSO-neutral during May-June-July 2011 (three-month average in the Nino-3.4 index between –0.5°C and +0.5°C; Figs. F1-F13).  Thereafter, the majority of models and all multi-model forecasts predict ENSO-neutral conditions to continue through the remainder of 2011.  However, the status of ENSO beyond the Northern Hemisphere summer remains uncertain due to lower model forecast skill at longer lead times.

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