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

AUGUST 2007

Forecast Forum

The canonical correlation analysis (CCA) forecast of SST in the central Pacific (Barnett et al. 1988, Science, 241, 192-196; Barnston and Ropelewski 1992, J. Climate, 5, 1316-1345), is shown in Figs. F1 and F2. This forecast is produced routinely by the Prediction Branch of the Climate Prediction Center . The predictions from the National Centers for Environmental Prediction (NCEP) Coupled Forecast System Model (CFS03) are presented in Figs. F3 and F4.  Predictions from the Markov model (Xue, et al. 2000: J. Climate, 13, 849-871) are shown in Figs. F5 and F6.   Predictions from the latest version of the LDEO model (Chen et al. 2000: Geophys. Res. Let., 27, 2585-2587) are shown in Figs. F7 and F8.  Predictions using linear inverse modeling (Penland and Magorian 1993: J. Climate, 6, 1067-1076) are shown in Figs. F9 and F10. Predictions from the Scripps / Max Planck Institute (MPI) hybrid coupled model (Barnett et al. 1993: J. Climate, 6, 1545-1566) are shown in Fig. F11.  Predictions from the ENSO-CLIPER statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633-652) are shown in Fig. F12.  Niño 3.4 predictions are summarized in Fig. F13, provided by the Forecasting and Prediction Research Group of the IRI.

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

 Outlook:

          La Niña conditions will develop further during the next 3 months.  

 Discussion:  

            During August 2007, negative sea surface temperature (SST) anomalies in the eastern equatorial Pacific expanded westward, and now extend from the coast of South America to the date line (180ºW) (Fig. T1).  Consistent with this additional cooling, three of the Niño indices remained cooler than −0.5 ºC throughout August, with only Niño 4 remaining average (August monthly values: Niño 1+2 (−1.6ºC), Niño 3 (−1.1ºC), Niño 3.4 (−0.5ºC), Niño 4 (+0.1ºC)) (Table T2).  The upper-ocean heat content (average temperatures in the upper 300 m of the ocean) in the central and east-central equatorial Pacific also remained below average, with temperatures at thermocline depth ranging from 1°C to 3°C below average (Fig. T17).  While not as pronounced as in previous months, the low-level easterly winds remained stronger than average in the west-central equatorial Pacific (Fig. T20), convection was suppressed throughout the central and eastern equatorial Pacific, and an area of slightly enhanced convection again covered parts of Indonesia and the far western Pacific (Fig. T25).  Collectively, the oceanic and atmospheric conditions reflect La Niña conditions.  

            The recent SST forecasts for the Niño 3.4 region range from ENSO-neutral to La Niña (Figs. F1-F13).  Nearly all of the dynamical ENSO models forecast the continuing development of La Niña during the next couple of months, and several of the statistical models also indicate the continuation of La Niña conditions through the end of the year.  Therefore, current atmospheric conditions (stronger than average easterlies over the west-central Pacific) and observed oceanic trends indicate that La Niña conditions will develop further and possibly strengthen during the next 3 months.  

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