Tropical
Highlights - September 2021
During September
2021, sea surface
temperatures (SSTs) were near-to-below average across much
of the central and eastern equatorial Pacific (Fig. T18). The latest monthly
Niņo indices (based on OISST) were +0.1°C for the Niņo 1+2 region, -0.3°C for the Niņo 3.4 region and -0.4°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 the eastern equatorial Pacific (Figs. T15,
T16). The
corresponding sub-surface temperatures were 1-6°C below-average (Fig. T17).
Also during September, the
lower-level easterly winds and the upper-level westerly winds were above-average
over much of the equatorial Pacific (Table
T1, Fig. T20, Fig. T21). Meanwhile,
tropical convection was suppressed near and west of the Date Line and enhanced
over Indonesia (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