East Pacific Upper Ocean Heat: First Warm Anomaly Since Last Summer

Potential Big Storm Scenario in Mid-Atlantic in 15 Days
02/21/2018, 12:40 pm EDT
Deluge of Rain Across Australian Drought Region Next Week
02/27/2018, 2:03 pm EDT
Show all

Appearance of a dramatic Kelvin Wave near the Dateline counters remaining cool subsurface temperatures to sustain a weak La Nina in the eastern Pacific resulting in a slight warm anomaly for upper ocean heat east of the Dateline.

Headline: Kelvin Wave near Dateline but no (MJO) push yet

Discussion: The weekly ENSO diagnostics update indicate Nino34 SSTA remains moderately within La Nina at -1.1C while just-about every other aspect of ENSO is much weaker including Nino4 (near Dateline) and Nino12 (off northwest coast of South America) which are near neutral (Fig. 1).  Upper ocean heat east of the Dateline now averages slightly warmer than normal for the first time since summer 2017 (Fig. 2). The primary contributor to the warmer upper ocean heat trend is a strong Kelvin Wave now east of the Dateline (Fig. 3). A MJO push of the Kelvin Wave into the East Pacific is not indicated for the moment. If the Kelvin Wave moves eastward the La Nina will dissipate.

Fig. 1: 12-week Nino SSTA observations indicate a steady weak La Nina.

Fig. 2: Upper ocean heat anomalies east of the Dateline in the equatorial Pacific Ocean.

Fig. 3: NOAA subsurface equatorial Pacific Ocean temperature anomaly analysis identifies a Kelvin Wave moving east of the Dateline.