Negative sea surface temperature
(SST) anomalies strengthened across the central and east-central equatorial
during December 2008 (Fig. T18).
The latest monthly SST index was -0.7°C in the Niņo-3.4 region,
and -0.6°C in the Niņo-4 region (Table T2).
The oceanic thermocline along
the equator, measured by the depth of the 20°C
isotherm, featured shallower-than-average depths across the eastern equatorial
Pacific during December (Figs. T15, T16).
Consistent with this pattern, subsurface temperatures in the region were 1-5oC
below average at thermocline depth (Fig. T17).
Enhanced low-level easterly
winds and upper-level westerly winds were present across the equatorial
during December (Figs. T20,
T21). These conditions continued to be associated
with suppressed convection over the central equatorial
and enhanced convection across
This combination of conditions suggests that La Niņa is developing.
the latest status of the ENSO cycle see the ENSO Diagnostic Discussion at: