ENSO-neutral conditions are expected to continue for the next one to two
months, with weak warm episode (El Niño) conditions likely by the end of
By the end of August equatorial SST anomalies greater than +0.5ºC were observed in most
of the equatorial Pacific, with anomalies exceeding +1.0ºC in the central Pacific between 165ºE
and 170ºW (Fig. 1). Correspondingly, the
SST departures in the Niño regions were all positive
(Fig. 2). Beginning in February the basin-wide upper ocean heat content
increased, and since early April positive anomalies have been observed (Fig.
early July weaker-than-average low-level equatorial easterly winds were
observed across most of the equatorial Pacific, and
the Southern Oscillation Index (SOI) was
negative for the fourth consecutive month. Collectively, these oceanic and atmospheric anomalies are consistent with
a trend toward warm episode (El Niño)
conditions in the tropical Pacific.
Over the past several months most of the statistical
and coupled model forecasts have trended towards warmer conditions in the
tropical Pacific through the Northern Hemisphere winter. The spread of the most recent
statistical and coupled model forecasts (ENSO-neutral to weak El Niño)
indicates some uncertainty in the outlooks (Fig.
recent conditions (weaker-than-average easterly winds over the central
equatorial Pacific) and warming trends in observed oceanic conditions support
a continuation of ENSO-neutral conditions for the next one to two months,
with weak warm episode (El Niño) conditions likely by the end of 2006.
This discussion is a consolidated effort of NOAA and its funded institutions.
Oceanic and atmospheric conditions
are updated weekly on the Climate
Prediction Center website
(El Niño/La Niña
Current Conditions and Expert Discussions). Forecasts for the evolution of El Niño/La Niña are updated monthly in the
Forecast Forum section of CPC's Climate
Diagnostics Bulletin. The next ENSO Diagnostics Discussion is scheduled for
2006. To receive
an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail