El Niño Southern Oscillation (ENSO) region sea surface temperature forecasts
Climate centres use several standard regional averages of sea surface temperature anomalies as indices to monitor the state of the equatorial Pacific ocean, especially the anomalous warming and cooling associated with El Niño and La Niña.
The diagrams below illustrate these indices as observed in recent months (in black), and the evolution predicted by the Met Office dynamical long-range ensemble forecast system (in red).
We also produce Tropical Atlantic and Indian Ocean sea surface temperature forecasts.
For each of several regions of the equatorial tropical Pacific the forecast graphs (called plume diagrams), show the predicted area average of monthly mean sea-surface temperature anomaly for each member of the ensemble forecast (red lines). The observed sea surface temperature anomaly for the six months preceding the forecast is also shown (black line).
Plume diagrams are provided for regions Niño3 (5° S-5° N, 150° W-90° W), Niño3.4 (5° S-5° N, 170° W- 120° W) and Niño4 (5° S-5° N, 160° E-150° W). These areas are commonly used for monitoring the anomalous warming and cooling in sea-surface temperature in the equatorial tropical Pacific associated with El Niño and La Niña. In particular, Niño3.4 is a commonly used indicator for the likely impact of El Niño and La Niña events on associated widespread global climate variability around the globe.
The Met Office contributes to the World Meteorological Organization's (WMO) statement on the state of the tropical Pacific.