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

JULY 2011

ENSO-neutral conditions continued during July 2011 as sea surface temperatures were near-average across much of the equatorial Pacific Ocean, except the far eastern equatorial Pacific (Fig. T18, Table T2). The latest monthly Niño indices were -0.2°C for the Niño 3.4 region and +0.5°C for the Niño 1+2 region (Table T2, Fig. T5). Consistent with these conditions, the oceanic thermocline (measured by the depth of the 20°C isotherm) was shallower than average in the east-central equatorial Pacific and remained slightly deeper than average in the far eastern Pacific (Figs. T15 and T16). The corresponding sub-surface temperatures were below average in the east-central equatorial Pacific and near-average in the eastern Pacific (Fig. T17).

The atmospheric circulation patterns during July continued to show some weak La Niña impacts.  The equatorial low-level easterly trade winds and upper-level westerly winds remained stronger than average over the central equatorial Pacific (Table T1, Figs. T20 and T21), while convection remained enhanced over Indonesia/western equatorial Pacific and suppressed across the central equatorial Pacific (Figs. T25 and E3). Collectively, these oceanic and atmospheric anomalies reflect ENSO-neutral conditions but with weakening La Niña impacts in the atmosphere.

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