The pattern of global tropical sea surface temperature
(SST) during May 2005 featured negative anomalies in the eastern equatorial
Atlantic and near-average SSTs elsewhere. The SST anomaly in the Niņo 3.4
region remained 0.4 during May and the Niņo 1+2 anomaly became slightly
positive for the first time since December 2004 (Fig. T18,
Table T2). The overall patterns of convection,
SST, low-level winds and upper-level winds were near average over the
tropical Pacific during May, which is consistent with ENSO-neutral
Intraseasonal (Madden-Julian Oscillation - MJO) activity
during May contributed to week-to-week variability in many tropical
atmospheric features (Figs. T10, T11,
T12, T13). The
Tahiti - Darwin SOI (latest value -1.2, Table T1,
Fig. T1) was negative, primarily in response to
higher-than-average pressure over Darwin.
The oceanic thermocline, measured by the depth of the 20°C isotherm,
featured near-average depth across the equatorial Pacific during May (Figs.
Consistent with these conditions, oceanic temperatures at thermocline depth
were near average throughout most of the equatorial Pacific (Fig. T17).