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Climate Prediction Center

Climate Diagnostics Bulletin
Climate Diagnostics Bulletin - Home Climate Diagnostics Bulletin - Forecast Climate Diagnostics Bulletin - Extratropics


  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


Forecast Forum

Atmospheric and oceanic indices during February 2008 indicated a further strengthening of La Niña. This strengthening is highlighted by a decrease in the Niño 4 sea surface temperature (SST) index to -1.6 and a drop in the Niño 3.4 index to -1.9, the lowest value since January 2000. Overall, equatorial sea surface temperatures (SST) were more than 2.0°C below average across parts of the central and east-central equatorial Pacific (Fig. T18). Meanwhile, the SST anomalies in the Niño 1+2 region became positive for the first time since February 2007 (Table T2, Figs. T5, T18).

Accompanying these surface conditions, the oceanic thermocline during February remained shallower than normal across the equatorial Pacific east of 150°W and continued to deepen in the region west of the Date Line (Fig. T16). Consistent with this structure, sub-surface temperature at thermocline depth remained below average (-2°C to -5°C) across the eastern equatorial Pacific, and above average west of 170°W (Fig. T17).

Strong low-level easterly anomalies persisted across the western and central equatorial Pacific during the month (Fig. T20, Table T1), which is consistent with the shallower-than-average thermocline in the central and eastern equatorial Pacific (Figs. T15, T16). These conditions were associated with enhanced convection (above-average rainfall amounts) across the Indian Ocean , Indonesia and the far western tropical Pacific, and a continuation of suppressed convection (below-average rainfall amounts) across the central equatorial Pacific (Figs. T25, T26, E3). Consistent with these anomalies, the Tahiti – Darwin SOI remained strongly positive for the third consecutive month (+2.7) (Table T1, Fig. T1), while the equatorial SOI remained above +3.0 (Fig. T2).

For the latest status of the ENSO cycle see the ENSO Diagnostic Discussion at:

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