Tropical Highlights – September 2012

 

 

 During September 2012, the sea surface temperatures (SSTs) remained warmer-than-average across the central and east-central equatorial Pacific (Fig. T18, Table T2). The latest monthly Niño indices were +0.5°C for both the Niño 3.4 and the Niño 1+2 regions (Table T2, Fig. T5). Consistent with these conditions, the depth of the oceanic thermocline (measured by the depth of the 20°C isotherm) remained near-average in the east-central equatorial Pacific and above-average in the eastern equatorial Pacific (Figs. T15, T16).

The Southern Oscillation Index (SOI) also remained near average, with the latest monthly index value being +0.2 (Table T1). Meanwhile, the equatorial low-level easterly trade winds remained slightly enhanced across the east-central equatorial Pacific and slightly weaker-than-average over the western equatorial Pacific (Table T1, Fig. T20). Enhanced convection was seen across the western equatorial Pacific and near the Date Line (Figs. T25, E3), which is consistent with weak El Niño conditions. Collectively, these oceanic and atmospheric anomalies reflect borderline ENSO-neutral/ weak El Niño 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