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 December 1, 1997, January 1, 1998 and
February 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 winter 1997-98
maximum to near normal conditions in the late spring early summer.
During the fall of 1998 the temperatures continue to cool 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.
| Time evolution of the NINO3 SSTA forecast. The solid red curve corresponds to the forecast initialized in December 1997, the dashed blue curve corresponds to the January 1998 forecast and the dotted green curve corresponds to the February 1998 forecast. |
The ensemble mean (average of all three forecasts) horizontal
structure of the predicted SSTA for
the spring, summer and fall of 1998,
are shown in the
three panels of the figure below. While the SSTA is rapid decaying
during the spring (MAM98), the SSTA remains relatively warm throughout
most of the tropical Pacific. By the summer season (JJA98) the early development
of cold anomalies in the far 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 (not shown).
| The ensemble mean SSTA. The top panel shows the predicted ensemble mean averaged from March to May 1998. The middle panel shows the predicted ensemble mean SSTA averaged from June 1998 to August 1998. The bottom panel shows the ensemble mean averaged over September 1998 to November 1998. |
These latest forecasts are consistent with the forecast from the previous period, and indicate that peak El Niño will rapidly decay through the spring giving near normal conditions for the summer. In addition, these forecast as well as the previous three forecasts call for relatively cold conditions for the boreal winter of 1998-99.
