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Forecast Forum
JUNE 2009
Forecast Forum
The
CPC and the contributors to the Forecast Forum caution potential users of
this predictive information that they can expect only modest skill.
ENSO
Alert System Status: El
Niņo Advisory
Outlook:
El Niņo conditions will
continue to develop and are expected to last through the Northern Hemisphere
Winter 2009-2010.
Discussion:
During
June 2009, conditions across the equatorial
Pacific Ocean
transitioned from
ENSO
-neutral to El Niņo
conditions. Sea surface temperature
(SST) anomalies continued to increase, with the latest monthly departures
exceeding +0.5°C across the equatorial Pacific (Fig. T18).
All of the SST indices increased during June and now range from +0.6°C to +0.7°C
(Table T2).
Subsurface oceanic heat content anomalies (average temperatures in the
upper 300m of the ocean) also increased as the thermocline continued to deepen (Fig.
T17). Consistent with the oceanic evolution, the
low-level equatorial trade winds were weaker-than-average across the eastern
Pacific basin (Fig. T20), and convection became increasingly suppressed over
Indonesia
(Fig. T25).
This coupling of the oceanic and atmospheric anomalies indicates the
development of El Niņo conditions.
Model
forecasts of SST anomalies for the Niņo-3.4 region (Figs. F1-F13)
reflect a growing consensus for the continued development of El Niņo (+0.5°C
or greater in the Niņo-3.4 region). However,
the spread of the models indicates disagreement over the eventual strength of El
Niņo (+0.5°C to +2.0°C). Current
conditions and recent trends favor the continued development of a
weak-to-moderate strength El Niņo into the Northern Hemisphere Fall 2009, with
further strengthening possible thereafter.
Weekly
updates of oceanic and atmospheric conditions are available on the Climate
Prediction
Center
homepage (El
Niņo/La Niņa Current Conditions and Expert Discussions).
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www.nws.noaa.gov
