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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 2009

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:  

            El Niño is expected to continue strengthening and last through at least the Northern Hemisphere Winter 2009-2010.

Discussion:    

During October 2009, sea surface temperature (SST) anomalies increased across the central and eastern equatorial Pacific Ocean (Fig. T9).  The monthly Niño-3.4 index increased to +1.0°C (Table T2).  Above-average subsurface temperature anomalies increased across a large region of the central and east-central Pacific, with anomalies ranging between +1 to +5°C by the end of the month (Fig. T17).  Consistent with this warming, subsurface oceanic heat content anomalies (average departures in the upper 300m of the ocean) also increased during the month.  In addition, low-level westerly and upper-level easterly wind anomalies strengthened over much of the equatorial Pacific (Fig. T20 and Fig. T21).  The pattern of tropical convection also remained consistent with El Niño, with enhanced convection over the west-central Pacific and suppressed convection over Indonesia (Fig. T25). Collectively, these oceanic and atmospheric anomalies reflect a strengthening El Niño. 

There continues to be disagreement among the models on the eventual strength of El Niño, but the majority indicate that the three-month average Niño-3.4 SST index value will range between +1.0°C and +1.5°C during the Northern Hemisphere winter (Figs. F1-F13).  Consistent with the historical evolution of El Niño, a peak in SST anomalies is expected during November-January.  Presently, there is considerable uncertainty over how long this event will persist. Most of the models suggest El Niño will last through March-May 2010, although the most likely outcome is that it will peak with at least moderate strength (3-month Niño-3.4 SST index of +1.0°C or greater) and last through at least the Northern Hemisphere winter 2009-10. 

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