Tropical
Highlights - December 2020
During December
2020, sea surface
temperatures (SSTs) remained below-average across the
central and eastern equatorial Pacific (Fig.
T18). The latest monthly Niņo indices were -0.7°C for
the Niņo 1+2 region, -1.0°C for the Niņo 3.4 region and -0.8°C for the Niņo 4 region (Fig. T5, Table T2). The depth of
the oceanic thermocline (measured by the depth of the 20°C isotherm) was below-average
across much of the eastern equatorial Pacific (Figs. T15,
T16). The
corresponding sub-surface temperatures were 1-4°C below-average in the eastern
equatorial Pacific (Fig. T17).
Also during December, the
lower-level easterly winds were above-average across the western and east-central
equatorial Pacific and the upper-level westerly winds were above-average over
much of the eastern equatorial Pacific (Fig.
T20, Fig. T21). Meanwhile,
tropical convection continued to be suppressed over the western and central
equatorial Pacific (Figs. T25, E3).
Collectively, these oceanic and atmospheric anomalies were consistent with La
Niņa conditions.
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