Fuel For La Nina In Question

Fig. 1: The 12-week Nino SSTA monitor indicates the recent the cool La Nina-spike weakened slightly last week.

Discussion: Diagnostics in support of a developing La Nina later in quarter 3 of 2020 have eased. Last week the Nino SSTA regions turned slightly warmer after a cool peak earlier this month (Fig. 1). Subsurface cool water required to fuel La Nina developed rapidly in May but is now fading through mid-June (Fig. 2). The air-to-sea link of ENSO is not happening as the cooler waters are not able to drive a positive southern oscillation index (Fig. 3) typically present during La Nina. Implied is any La Nina ahead is likely weak and short-lived.

Fig. 2: Upper ocean heat in the eastern equatorial Pacific Ocean has trended less cool the past couple weeks.

Fig. 3: Positive phase southern oscillation index which is present during La Nina is not developing.