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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

OCTOBER 2008

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

     Outlook:  

            ENSO-neutral conditions are expected to continue into early 2009.   

      Discussion:    

ENSO-neutral conditions continued during October 2008, as equatorial sea surface temperatures (SSTs) were near-average across much of the Pacific Ocean , except for small areas of below-average SSTs in the east-central Pacific and off the coast of South America (Fig. T18). Correspondingly, the latest monthly SST index values were near-average in all Niño regions (Table T2).  Subsurface oceanic heat content anomalies (average temperatures in the upper 300m of the ocean) became less negative due to the eastward shift of positive temperature anomalies at thermocline depth to ~160°W, but anomalies remained negative in the eastern half of the Pacific (Fig. T17). 

The atmospheric winds and convection patterns exhibited a high degree of week-to-week variability across the tropical Pacific during October in response to the Madden-Julian Oscillation (MJO) (Figs. T11, T12). The cumulative effects of the MJO were 1) above-average convection over Indonesia , and 2) enhanced low-level easterly winds, enhanced upper-level westerly winds, and suppressed convection over the western and central equatorial Pacific (Figs. T20, T21, and T25).  Overall, the ocean-atmosphere system remains consistent with ENSO-neutral conditions. 

A majority of the SST forecasts indicate a continuation of ENSO-neutral conditions (−0.5°C to 0.5°C in the Niño-3.4 region) into the first half of 2009 (Figs. F1- F13).  Several dynamical models suggest the development of a La Niña during Northern Hemisphere Winter 2008-09.  This outcome becomes more likely if the current MJO were to stall in a location that favors enhanced low-level easterlies and increased upwelling in the east-central and eastern Pacific.  However, it is rare for La Niña to develop late in the year.  Therefore, based on current atmospheric and oceanic conditions and recent trends, ENSO-neutral conditions are expected to continue into early 2009.

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