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.
The NINO3 time series of the predicted SSTA for three
forecasts initialized on the first day of September, October and November
1997, are shown below. Each forecast is run for 18 months.
The
evolution of all three forecasts are consistent.
The model
predicts steady anomalously warm conditions (2ºC) in the eastern Pacific
from the initial state (boreal Fall 1997) through the boreal winter of
1997-98 and early boreal Spring. During boreal spring 1998 the NINO3
anomalies in all three forecasts decay rapidly to near normal
conditions by the boreal summer of 1998 with rather strong cold
conditions by the winter of 1998-99.
| Time evolution of the NINO3 SSTA forecast. The solid red curve corresponds to the forecast initialized in September 1997, the dashed blue curve corresponds to the October 1997 forecast and the dotted green curve corresponds to the November 1997 forecast. |
The ensemble mean (average of all three forecasts) horizontal
structure of the predicted SSTA for the
boreal winter of 1997-98, the
boreal spring of 1998 and the boreal summer of 1998
are shown in the three panels below.
The ensemble mean forecast for DJF97-98
indicates strong warm conditions throughout most of the eastern and
central Pacific Ocean. In the far western Pacific there are
substantial cold anomalies on both sides of the equator. By MAM98 the
warm anomalies in the central and eastern Pacific and the cold
anomalies in the western Pacific have decayed by approximately 50%.
The rapid transition from warm conditions to relatively cold
conditions seen in the plot above is also apparent in the figure below. By JJA98 the
initial development of the cold phase of the ENSO can be easily
detected.
| The ensemble mean SSTA. The top panel shows the predicted ensemble mean averaged from December 1997 to February 1998. The middle panel shows the predicted ensemble mean SSTA averaged from March 1997 to May 1998. The bottom panel shows the ensemble mean averaged over June 1998 to August 1998. |
These latest forecasts are consistent with the forecast from the previous period, and indicate that peak El Niño conditions can be expected for the winter of 1997-98. In addition, these forecasts call for a rapid transition from warm conditions for this boreal winter to relatively cold conditions for the boreal winter of 1998-99.
