Tropical Highlights

  Table of Atmospheric Indices  (Table 1)

  Table of Oceanic Indices  (Table 2)

  Time Series

  Time-Longitude Sections

  Mean & Anomaly Fields

  Appendix 1: Outside Contributions

Tropical Highlights

SEPTEMBER 2010

Negative sea surface temperature (SST) anomalies continued to strengthen across the equatorial Pacific Ocean during September 2010 (Fig. T18). The monthly Niño indices were -1.6°C for both Niño 3.4 and Niño 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 6°C below average in these regions (Fig. T17).

Also during September, 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 a strengthening of La Niña conditions.

Elsewhere, enhanced convection (above-average rainfall amounts) was observed observed over the North Atlantic/Caribbean Sea and across the west African monsoon region during September (Figs. T25 and E3), which is consistent with a very active Atlantic hurricane season.

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