conditions are expected to continue for the next one to three months, with a
50% chance that weak El Niño conditions will develop by the end of 2006.
Equatorial surface and subsurface temperature
anomalies increased during July 2006, with SST anomalies greater than +0.5C
observed in most of the equatorial Pacific between 130ºE and 140ºW (Fig.
1). As a result, positive SST anomalies were observed in all of the Niño
regions (Fig. 2). During July, low-level (850-hPa) easterly winds were weaker
than average across most of the equatorial Pacific, and the Southern
Oscillation Index (SOI) was negative for the third consecutive month.
Beginning in February the basin-wide upper ocean heat content increased, and
since early April positive anomalies have been observed (Fig.
upper-ocean heat content anomalies are usually a precursor to warm (El Niño) episodes.
The statistical and coupled model forecasts
range from ENSO-neutral to weak warm (El Niño)
episode conditions for the remainder of 2006 and into early 2007 (Fig.
4). The forecasts are
consistent with the recent build up in upper-ocean heat content along the
equator (Fig. 3), indicating a trend toward warm-episode conditions. In the
absence of any strong intraseasonal (Madden-Julian Oscillation – MJO)
activity, a continued slow trend toward warm-episode conditions is expected.
Therefore, ENSO-neutral conditions are expected to continue for the next one
to three months, with a 50% chance that weak El Niño conditions will develop
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