Current ENSO Information
ENSO Update
16 September 2004
Summary
Overall conditions in the tropical Pacific are currently indicative of
a weak El
Niño. Based
on
the latest observations and forecasts, it is at least 60% likely that
weak El Niño conditions will prevail through early 2005.
General Discussion
Weak El Niño conditions developed in the
east-central tropical Pacific
in late July, with sea surface temperatures of 1 degree C above
average along the equator from 170E to 120W. Below average sea surface
temperatures continue in
the far eastern tropical Pacific. The tropical Pacific atmospheric
conditions have just recently begun to show
characteristics of El Niño development. Out of a large set of
dynamical and
statistical
forecast models, about 60% predict sea surface temperatures at weak El
Niño levels for the coming season, and several of the
models not currently indicating El Niño conditions warm to that
level by the end of the year, indicating approximately 70% probability
of weak El Niño conditions through early 2005.
Overall, based on model forecasts and current observations of
the ocean surface and subsurface, the chances for El Niño
conditions are aproximately equal to 60% from September through
December 2004, increasing to 70% by the end of the calendar
year and
into early 2005, and decreasing thereafter. The likelihood
of neutral conditions is below the climatological
likelihood (i.e. equal to or greater than 50% probability) through 2004
and early 2005. The
probability of development
of La Niña conditions is believed to be much less than that
of an average year (i.e. less than 25%).
Note 1 - Only models
that produce a new ENSO forecast every month are included in the above
statement.
Top of Page
|
