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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

NOVEMBER 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 or La Niña conditions are equally likely through early 2009.  

      Discussion:    

ENSO-neutral conditions continued during November 2008, although equatorial sea surface temperatures (SSTs) were slightly below-average across parts of the central and eastern Pacific Ocean (Fig. T18). Correspondingly, the latest monthly SST index values were -0.2°C in all the Niño regions, except for a value of -0.3°C in the Niño 4 region (Table T2).  The subsurface oceanic heat content anomalies (average temperatures in the upper 300m of the ocean) became increasingly negative as below-average temperatures at thermocline depth expanded throughout the central and eastern Pacific (Fig. T17). 

Low-level easterly winds and upper-level westerly winds expanded and strengthened across the equatorial Pacific Ocean November (Figs. T20 and T21).  Also, convection remained enhanced near Indonesia and suppressed near the International Date Line (Fig. T25).  However, in recent months intraseasonal variability has contributed to episodic strengthening and weakening of convection over Indonesia .  Overall, the ocean-atmosphere system during November remained consistent with ENSO-neutral conditions, but exhibited several atmospheric characteristics typical of weak La Niña conditions.

A majority of the SST forecasts indicate ENSO-neutral conditions (Niño-3.4 index of −0.5°C to 0.5°C) will continue into the first half of 2009 (Figs. F1- F13).  Several models, including the NOAA Climate Forecast System (CFS), suggest the development of La Niña during December 2008- March 2009.  The recent strengthening of the low-level easterlies over the equatorial Pacific suggests the possibility of additional anomalous cooling of the SSTs.  However, the magnitude of such cooling remains uncertain and it is possible the La Niña threshold will not be met (3-month average of the Niño-3.4 index less than or equal to −0.5°C).  Therefore, based on current observations and recent trends, ENSO-neutral or La Niña conditions are equally likely through 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).