Tropical Highlights - November 2004

Sea surface temperature (SST) anomalies remained positive across the central and east-central equatorial Pacific during November 2004.  The SSTs in the eastern equatorial Pacific have increased from near average to above average, with a November value of 0.3 in the Niño 1+2 region (Fig. T18, Table T2).  The pattern of Tropical SSTs during November featured positive anomalies greater than +1.0°C between 160°E and 150°W (Fig. T18).  The SST anomaly in the Niño 3.4 region remained 0.8, the highest value since January 2003, and the Niño 4 anomaly increased to 1.2, the highest value since November 2003 (Table T2).  Meanwhile, atmospheric features continued to show month-to-month variability associated with intraseasonal (Madden-Julian Oscillation - MJO) activity, although the MJO activity during November was weaker than that in previous months (Figs. T11, T12, T13, Table T1). 

The oceanic thermocline, measured by the depth of the 20°C isotherm, remained slightly deeper than average across most of the equatorial Pacific during November (Figs. T15, T16). Consistent with these conditions, oceanic temperatures at thermocline depth were 1-2°C above average across most of the equatorial Pacific (Fig. T17). 

During November, near-average low-level winds were observed over the equatorial Pacific (Fig. T20). The global Tropics featured near-average convection, with the exception of enhanced convection over the Indian Ocean and the equatorial Pacific west of the date line (Fig. T25). The Tahiti - Darwin SOI (latest value -0.9, Table T1, Fig. T1) has been negative during the past 6 months, primarily in response to higher-than-average pressure over Darwin.