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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

JULY 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: La Niña Advisory      

Outlook:  

            La Niña conditions are expected to strengthen and last through the Northern Hemisphere winter 2010-11.

Discussion:    

During July 2010 La Niña conditions developed, as negative sea surface temperature (SST) anomalies strengthened across the central and eastern equatorial Pacific Ocean (Fig. T18).  All of the Niño indices decreased with values near -1.0°C in the Niño 3 and 3.4 regions at the end of the month (Table T2).  The subsurface heat content (average temperatures in the upper 300m of the ocean) continued to reflect a deep layer of below-average temperatures east of the Date Line (Fig. T17).  Also convection was enhanced over Indonesia, while remaining suppressed over the western and central tropical Pacific (Fig. T25).  Enhanced low-level easterly trade winds and anomalous upper-level westerly winds continued over the western and central equatorial Pacific (Figs. T20, T21).  Collectively, these oceanic and atmospheric anomalies reflect the development and strengthening of La Niña conditions. 

            Nearly all models predict La Niña to continue through early 2011 (Figs. F1-F13).  However, there is disagreement among the models over the eventual strength of La Niña. Most dynamical models generally predict a moderate-to-strong La Niña, while the majority of the statistical model forecasts indicate a weaker episode. Given the strong cooling observed over the last several months and the apparent ocean-atmosphere coupling (positive feedback), the dynamical model outcome of a moderate-to-strong episode is favored at this time.  Therefore, La Niña conditions are expected to strengthen and last through Northern Hemisphere Winter 2010-11.   

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