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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

MAY 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: Final La Niña Advisory      

Outlook:  

           ENSO-neutral conditions have developed and are expected to continue at least through the Northern Hemisphere summer 2011.

Discussion:    

A transition from La Niña to ENSO-neutral conditions occurred during May 2011 as indicated by generally small sea surface temperature (SST) anomalies across the equatorial Pacific Ocean east of the Date Line (Fig. T18). The May Niño index values (Table T2) were slightly below-average in the central and east-central equatorial Pacific (Niño-4 index of –0.5°C and Niño 3.4 index of –0.5°C), and above-average SSTs in the eastern equatorial Pacific (Niño-1+2 index of +0.8°C).  The subsurface oceanic heat content anomalies (average temperatures in the upper 300m of the ocean) remained elevated, but relatively constant during the month, reflecting a large area of above-average temperatures at depth (Fig. T17).  Consistent with other transitions to ENSO-neutral conditions, the atmospheric circulation anomalies continued to show some features consistent with La Niña, albeit at weaker strength.  Convection was enhanced over eastern Indonesia and suppressed over the central equatorial Pacific (Fig. T25).  Also, anomalous low-level easterly and upper-level westerly winds weakened but persisted over the central Pacific (Figs. T20, T21).  Collectively, these oceanic and atmospheric anomalies reflect a transition to ENSO-neutral conditions, but with lingering La Niña-like atmospheric impacts, particularly in the global Tropics. 

Current observed trends, along with forecasts from a majority of the ENSO models, indicate ENSO-neutral will continue through the Northern Hemisphere summer 2011 (three-month average in the Nino-3.4 index between –0.5°C and +0.5°C; Figs. F1-F13).  Thereafter, most models and all multi-model forecasts predict ENSO-neutral to continue through the remainder of 2011.  However, the status of ENSO beyond the Northern Hemisphere summer remains more uncertain due to lower model forecast skill at longer lead times, particularly during this time of year.

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