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 March 1, April 1, and
May 1, 1998 are shown below. Each forecast is run for 18 months.
The evolution of all three forecasts are consistent.
The model
predicts a rapid decay of the NINO3 SSTA from the warm anomalies during
spring 1998 to near normal conditions in the late spring early summer.
During the fall of 1998 the temperatures continue to cool rapidly with NINO3
SSTA more than one standard deviation below normal. The cold anomalies
peak during the winter of 1998-99 with strong La Niña conditions
persisting through the spring of 1999. The NINO3 SSTA return to normal
during the summer and fall of 1999.
| Time evolution of the NINO3 SSTA forecast. The solid red curve corresponds to the forecast initialized in March 1998, the dashed blue curve corresponds to the April 1998 forecast and the dotted green curve corresponds to the May 1998 forecast. |
The ensemble mean (average of all three forecasts) horizontal
structure of the predicted SSTA for
the summer and fall of 1998,
as the winter of 1998-99,
are shown in the
three panels of the figure below.
During the summer season (JJA98) the development
of cold anomalies in the central and eastern Pacific can be detected.
Cold anomalies dominate most of the tropical Pacific basin by fall
(SON98) and mature La Niña conditions prevail during the winter of
1998-99.
| The ensemble mean SSTA. The top panel shows the predicted ensemble mean averaged from June to August 1998. The middle panel shows the predicted ensemble mean SSTA averaged from September 1998 to November 1998. The bottom panel shows the ensemble mean averaged over December 1998 to February 1999. |
These latest forecasts are consistent with the forecast from the previous period, and indicate that the El Niño will rapidly decay through the spring giving near normal or slightly cold conditions for the summer. In addition, these forecast as well as the previous three forecasts call for strong cold conditions for the boreal winter of 1998-99.
