Current ENSO Information
Summary of ENSO Model Forecasts
16 January 2003
Note on interpreting model forecasts
The following graph and table show forecasts made by dynamical and statistical
models for SST in the Nino 3.4 region for nine overlapping 3-month periods.
Note that the expected skills of the models, based on historical performance,
are not equal to one another. The skills also generally decrease as the
lead time increases. Thirdly, forecasts made at some times of the year
generally have higher skill than forecasts made at other times of the year--namely,
they are better when made between June and November than when they are
made between January and May. Differences among the forecasts of the models
reflect both differences in model design, and actual uncertainty in the
forecast of the possible future SST scenario.
Discussion of current forecasts
The set of dynamical and statistical model forecasts issued during late
December 2002 and early January 2003 shows a range of possible sea surface
temperature conditions for the coming 2 to 9 months (January - February
- March through September - October - November 2003). Nearly all models
are indicating a weakening of El Nino conditions over the next few months,
with more significant weakening during the March to June period.
Most of the models forecast sea surface temperatures sufficient to be called
an El Nino for February-March-April (0.6 degrees C or more above average
in the Nino 3.4 region for the seasonal average) while only half predict
similar conditions for April-May-June, with the remainder forecasting ENSO
conditions in the neutral category--within 0.6 degrees C from normal.
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