Discussion: The Climate Impact Company probability forecast of ENSO phase has been adjusted STRONGER/MORE LIKELY for El Nino to form later in 2018 (Fig. 1). There is risk of El Nino onset as early as late summer which would diminish tropical cyclone activity in the North Atlantic basin. The primary diagnostic lending support for the El Nino scenario is the accelerated warming of the East Pacific subsurface (Fig. 2). The Nino SSTA regions are now in neutral ENSO except Nino12 off the northwest coast of South America which (interestingly) has trended cooler (Fig. 3). The subsurface warming should reach the northwest coast of South America by next month.
Fig. 1: Climate Impact Company ENSO phase probability predictor for 2018.
Fig. 2: Persistent robust warming of the East Pacific equatorial subsurface is an indicator of La Nina’s demise and increased risk of El Nino later in 2018.
Fig. 3: 12-week Nino SSTA observations indicate La Nina is ending.