Tropical
Highlights - December 2018
Sea surface
temperatures (SSTs) remained above-average across
the equatorial Pacific during December 2018 (Fig. T18, Table T2).
The latest monthly
Niņo indices were +0.8°C for the Niņo 1+2
region, and +1.0°C
for the Niņo 3.4 and Niņo 3 regions
(Table T2,
Fig. T5). The depth
of the oceanic thermocline (measured by the depth of the 20°C isotherm) was above-average
across the eastern equatorial Pacific (Figs. T15,
T16), and the
corresponding sub-surface temperatures were 1-4°C above average (Fig. T17).
Also during December, the lower-level
easterly winds were slightly weaker-than-average (indicated by westerly
anomalies) over the eastern equatorial Pacific (Table T1, Fig. T20),
while the upper-level westerly winds anomalies were near-average across the western
and central equatorial Pacific (Fig. T21). Meanwhile, tropical convection was near-average
over Indonesia and enhanced just west of the Date Line (Figs. T25, E3). Collectively, these oceanic and
atmospheric anomalies reflect ENSO-neutral, but with continued evolution toward
El Niņo.
For the latest status of the ENSO
cycle see the ENSO Diagnostic Discussion at:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.html
www.nws.noaa.gov
