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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

APRIL 2008

Forecast Forum

Oceanic indices indicated a further weakening of La Niņa during April 2008 (Table T2). Negative SST anomalies weakened in the central and east-central equatorial Pacific Ocean , while positive SST anomalies were confined to parts of the eastern equatorial Pacific (Fig. T18). The latest weekly Niņo-3.4 index was -0.9°C, and the Niņo-4 index was -1.0°C.

Accompanying these surface conditions, the oceanic thermocline was near normal across the equatorial Pacific east of 150°W during April, and continued to deepen west of the Date Line (Fig. T16). Consistent with this structure, sub-surface temperatures at thermocline depth became above average (+1°C to +3°C) across the eastern equatorial Pacific and in the area west of 170°W (Fig. T17).

Strong low-level easterly anomalies persisted across the western and central equatorial Pacific during April (Fig. T20, Table T1) in association with the ongoing pattern of enhanced convection across the far western tropical Pacific and suppressed convection over the central equatorial Pacific (Figs. T25, E3). These atmospheric anomalies continue to strongly reflect La Niņa.

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

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Page Last Modified: May 2008
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