Tropical Highlights - April 2018

 

 

Sea surface temperatures (SSTs) during April 2018 were near-average across the central and eastern equatorial Pacific (Fig. T18, Table T2). The latest monthly Niño indices were +0.1°C for the Niño 4 region, -0.4°C for the Niño 3.4 region, and -1.0°C for the Niño 1+2 region (Table T2, Fig. T5). The depth of the oceanic thermocline (measured by the depth of the 20°C isotherm) was above-average in the east-central equatorial Pacific and below-average in the far eastern equatorial Pacific (Figs. T15, T16). The corresponding sub-surface temperatures were 1-2°C above average across most of the east-central equatorial Pacific and below average near the west coast of South America (Fig. T17).

 

Also during April, the lower-level easterly winds were above-average over the east-central equatorial Pacific while the upper-level westerly winds were above-average over the eastern equatorial Pacific (Table T1, Figs. T20, T21). Meanwhile, convection was suppressed across the central and eastern equatorial Pacific and slightly enhanced over the western equatorial Pacific (Figs. T25, E3). Collectively, these oceanic and atmospheric anomalies reflect ENSO-neutral conditions.

 

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