Discussion: Subsurface cooler-than-normal water required to initiate and sustain La Nina in the eastern equatorial Pacific is diminishing rapidly. At the surface, the Nino SSTA regions are (generally) warming especially the Nino34 region where ENSO phase is monitored has warmed to -0.6C this past week (Fig. 1) barely qualifying for La Nina. The upper ocean heat east of the Dateline in the equatorial Pacific has faded to neutral (Fig. 2). In January the subsurface cool profile in the equatorial East Pacific is weakening along the fringes with warming at depth already occurring in the East Pacific (Fig. 3).
Fig. 1: The 12-week Nino SSTA observations indicate a steady La Nina episode weakening the past week or so.
Fig. 2: Upper ocean heat east of the Dateline is weakening rapidly.
Fig. 3: During January the subsurface equatorial Pacific Ocean has shown a trend for eastward warm expansion while the cool anomaly sustaining La Nina is weakening.