Published in the Experimental Long-Lead Forecast Bulletin, June 1995
The El Niño forecasts are part of an ongoing research effort at COLA, and do not represent official forecasts. These forecasts should not be used as the basis of any commercial, policy, or other decisions. They are strictly research tools for advancing the understanding of the ocean-atmosphere system.
Shown below are the NINO3 time series of the predicted SSTA for three forecasts initialized on July 1, 1994, January 1, 1995 and April 1, 1995 respectively. Each forecast is for 18 months although only the last 12 months of the July 1, 1994 forecast is shown. The observed (Climate Diagnostics Bulletin, April 1995 Table T1 and the value for May 1995 data was provided by J. Copman CAC, personal communication) NINO3 SSTA for May 1994-May 1995 is also shown. Both the July 1994 and the January 1995 forecasts predict relatively warm NINO3 temperatures throughout most of the summer of 1995, whereas the observed temperature is warm in the winter of 1994-95 but returns to near normal conditions by spring 1995. The April forecast indicates relatively cold temperatures throughout most of the forecast period, however, there is a short lived return to near normal conditions in the Fall of 1995. By the winter of 1995-96 both the January and the April forecasts indicate moderate La Niña conditions.
Time evolution of the NINO3 SSTA forecast. The dotted curve is the last 12 months of the forecast initialized in July 1994, the long dashed curve is for the forecast initialized in January1995 and the long-short dashed curve corresponds to the forecast initialized in April 1995. The solid curve is the observed SSTA.
The horizontal structure of the predicted (April 1, 1995 initial condition) SSTA for the Fall of 1995 and the winter of 1995-96 is shown below. In the fall of 1995 the model predicts a -0.3 to -0.9ēK SSTA throughout a sizable region in central Pacific and somewhat weaker anomaly in the eastern Pacific. In the following winter season, the prediction indicates more mature La Niña conditions with anomalies on the order of -1.0ēK in the eastern Pacific. The meridional structure of the predicted SSTA is narrowly confined to the equator particularly in the eastern Pacific. Excessive equatorial trapping of the SSTA is a systematic error of this model and applying a statistical correction gives a broader meridional structure to the predicted SSTA.
Top panel shows the September-October-November 1995 mean SST anomaly for the forecast initialized in April 1995 forecast. Bottom panel show the December-January-February 1995-96 SSTA for the forecast initialized in April 1995.
In summary, the COLA prediction system indicates moderate La Niña conditions for the winter of 1995-96.
