Tropical Highlights
APRIL 2010
Forecast Forum
El
Niņo weakened during April
2010, as the sea surface temperature
(SST) anomalies decreased across most of the equatorial Pacific Ocean (Fig.
T18).
The latest monthly SST indices were +0.7°C for both the Niņo-3.4
and the Niņo-3 regions. (Table
T2, Fig. T5).
Consistent with this evolution, the
oceanic thermocline (measured by the depth of the 20°C
isotherm) was shallower than average across the central equatorial Pacific (Figs.
T15, T16), with
sub-surface temperatures remaining below average in that region (Fig. T17).
Also
during April, equatorial low-level easterly winds remained stronger than average
over the western Pacific, while the upper-level westerly wind anomalies
persisted across the central Pacific (Table
T1, Figs. T20
and T21).
This wind pattern was associated with enhanced convection over Indonesia and
suppressed convection across the equatorial Pacific, south of the equator (Figs.
T25, T26
and E3).
Collectively, these oceanic and atmospheric anomalies reflect a weakening El Niņo.
For
the latest status of the ENSO cycle see the ENSO Diagnostic Discussion at:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.html
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