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ENSO Quick
Look IRI ENSO Update / Forecast Technical ENSO Update IRI Probabilistic ENSO Forecast ENSO Prediction Plume Monthly archive ENSO Update18 June 2009SummaryThe equatorial Pacific has warmed to the borderline of weak El Niño conditions. During the Jun-Aug season there is an approximately 56% probability of at least weak El Niño conditions, and a 43% probability of retaining ENSO-neutral conditions. Probabilities for El Niño rise to near or slightly greater than 60% for the remainder of 2009, with probabilities for ENSO-neutral conditions approximately 35 to 40%.General Discussion
Between early April and mid-June 2009, the NINO3.4 SST anomaly index has
risen from values indicative of weak La Niña conditions through
ENSO-neutral values, and is currently at the threshold of
weak El Niño territory. Atmospheric conditions are still mainly
ENSO-neutral in character, due in part to persistence of some La
Niña oceanic and atmospheric features in the western Pacific.
However, westerly low-level wind anomalies in this same region, and
an above-average sub-surface oceanic heat content across the central
and eastern equatorial Pacific, portend likely further development
of the oceanic aspects of El Niño. Expected increasing SST
anomalies in the central and eastern tropical Pacific will provide
increased opportunity for coupling to the atmosphere in the
coming several months.
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