Tropical Highlights
JANUARY 2011
Forecast Forum
La
Niņa continued during January 2011 as sea surface temperatures (SSTs) remained
well below average across the equatorial Pacific Ocean (Fig.
T18).
The latest monthly Niņo indices
were -1.7°C for the Niņo
3.4 region and -0.7°C for the
Niņo
1+2 region (Table T2,
Fig. T5).
(Please note that starting with this
January 2011 issue, the anomalies are departures from the 1981-2010 base period
means.) Consistent with these conditions, 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 4°C
below average in these regions (Fig.
T17).
Also
during January, the equatorial low-level easterly trade winds remained stronger
than average over the western and central Pacific (Table T1, Fig.
T20), while convection remained enhanced over
Indonesia and suppressed across the western and central equatorial Pacific (Figs.
T25 and E3).
Collectively, these oceanic and atmospheric anomalies reflect the mature phase
of 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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