Tropical Highlights -
Surface and sub-surface oceanic conditions across the Tropical Pacific
continued to trend towards a weak warm episode during November 2003 (Table
T2), while atmospheric features continued to reflect ENSO-neutral
conditions (Table T1). Sea surface temperature (SST) anomalies
remained above normal across the entire equatorial Pacific during November (Fig.
T18), with the largest departures (exceeding 1°C)
observed in the western and central Pacific. For the Niño-4 region, which
spans the central equatorial Pacific, SST departures reached their highest
values since February 2003 (Table T2, Fig. T5).
Oceanic thermocline depths, measured by the depth of the 20°C
isotherm (Figs. T15, T16), remained slightly deeper than average
across most of the equatorial Pacific during November. Consistent with these
conditions, oceanic temperatures at thermocline depth were 1-2°C
above average across most of the equatorial Pacific (Fig. T17).
The low-level and upper-level equatorial winds remained near average
across the tropical Pacific during November (Table T1, Figs.
T21), and the Tahiti-Darwin SOI remained near zero (-0.4) (Table
Fig. T1). Also, relatively weak Outgoing Longwave Radiation (OLR)
anomalies were observed throughout much of the global Tropics, although
convection was suppressed near the date line and enhanced over the western
Pacific (Fig. T25). Since September there has been a tendency for
convection to be enhanced over the equatorial Pacific between 130°E
and 160°E (Fig. T11). None
of these indicators has exhibited any trend towards a warm or cold episode
during the past six months, and all are consistent with ENSO- neutral