Discussion: Last week the Nino34 SSTA warmed to above the El Nino threshold (Fig. 1). However, neutral ENSO remain intact. Subsurface waters are not sufficiently warm to allow an El Nino to generate (Fig. 2). The warm temperatures in the equatorial Pacific near the Dateline have caused a Modoki-like SSTA pattern to generate in recent weeks (Fig. 3). Despite short-term borderline El Nino characteristics the NCEP CFS V2 and NMME models are trending stronger with a developing La Nina for northern hemisphere summer (Fig. 4-5).
Fig. 1: The 12-week Nino SSTA observations sudden warming of the Nino34 SSTA region into weak El Nino. However, overall ENSO is in neutral phase.
Fig. 2: Upper ocean heat across the equatorial Pacific is very borderline to support any El Nino development.
Fig. 3: The Modoki ENSO index has strengthened in recent weeks as warming near the Dateline is quite intense while the eastern equatorial Pacific is relatively cool.
Fig. 4: The NCEP CFS V2 Nino34 SSTA forecast trends stronger with La Nina by northern hemisphere summer.
Fig. 5: The NMME global SSTA forecast also projects La Nina for JUN/JUL/AUG 2020.
Fig. 6: NOAA/CPC La Nina historical climate impacts for JUN/JUL/AUG.