Tropical Highlights
DECEMBER 2010
Forecast Forum
A
moderate-to-strong La Niņa continued during December 2010 as sea surface
temperatures (SSTs) remained below average across the equatorial Pacific Ocean (Fig.
T18).
The latest monthly Niņo indices were -1.5°C for both of the Niņo
3.4 and Niņo
1+2 regions (Table T2,
Fig. T5).
Consistent with this evolution, the oceanic thermocline (measured by the
depth of the 20°C
isotherm) remained much shallower than average across the central and eastern
equatorial Pacific (Figs. T15 and
T16), with sub-surface temperatures
reaching 1°C to 5°C
below average in these regions (Fig. T17).
Also
during December, equatorial low-level easterly trade winds and upper-level
westerly winds remained stronger than average over the western and central
Pacific (Table T1,
Figs. T20 and
T21). This wind pattern was associated with
enhanced convection over Indonesia and suppressed convection across the western
and central equatorial Pacific (Figs. T25
and E3). Collectively, these
oceanic and atmospheric anomalies reflect the ongoing La Niņa.
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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