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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 2010

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: El Niño Advisory      

Outlook:  

            A transition to ENSO-neutral conditions is expected by June 2010, which will continue into the Northern Hemisphere summer 2010. 

Discussion:    

El Niño weakened during April 2010 as positive surface temperature (SST) anomalies decreased across the equatorial Pacific Ocean.  However, SST anomalies still exceeded +0.5°C across most of the Pacific at the end of the month (Fig. T18, Table T2).  Since the end of February, subsurface heat content anomalies (average temperatures in the upper 300m of the ocean) have decreased steadily in association with the expansion and strengthening of below-average temperatures at depth (25-200m; Fig. T17).  Also, enhanced convection developed over Indonesia, while suppressed convection strengthened and expanded over the tropical Pacific, south of the equator (Fig. T25).  The low-level equatorial trade winds remained near-average, and anomalous upper-level westerly winds prevailed over the central Pacific during much of April (Figs. T20, T21).  Collectively, these oceanic and atmospheric anomalies reflect a weakening El Niño.

Nearly all models predict decreasing SST anomalies in the Niño-3.4 region through the Northern Hemisphere summer 2010 (Figs. F1-F13).  Most models predict a transition to ENSO-neutral conditions during April-June 2010, followed by ENSO-neutral conditions through the end of the year.  However, by July-September 2010, the envelope of model solutions includes a significant number (nearly a third) indicating the onset of La Niña conditions.  Even though ENSO-neutral conditions are most likely during the second half of the year, the general tendency of the models in recent months has been toward increasingly negative SST anomalies in the Niño-3.4 region.  These forecasts, in addition to various oceanic and atmospheric indicators, indicate a growing possibility of La Niña developing during the second half of 2010.   

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