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10/15/2018, 11:22 am EDT

Weekly ENSO Diagnostics: Plenty of Upper Ocean Heat

A LOT of FUEL for El Nino! Modoki-style El Nino (at first) then a full-tilt El Nino (similar to 1986-87) seems to be emerging Discussion: Upper ocean heat to fuel El Nino 2018-19 is building but the core is still located near or just east of the Dateline (Fig. 1). During the past 2-3 weeks a westerly wind burst in the tropical East Pacific (Fig. 2) allowed some of that central/east-central equatorial Pacific warmth to extend eastward making El Nino onset likely a very short time from now…likely in November. The Nino SSTA regions were all within El Nino thresholds 2 weeks ago while last week the Nino12 region (off the coast of South America) cooled back to the normal range (Fig. 3). The recent warming in the far eastern equatorial Pacific has contributed to a more El Nino-like multi-variate ENSO index (MEI), a measure of the atmospheric response to the ENSO regime (Fig. 4). The tilt of the surface/subsurface warmth in the equatorial Pacific Ocean toward the Dateline implies monitoring of El Nino Modoki. The Modoki index was positive in August and may be headed back that way in October/November (Fig. 5). Upper ocean heat is immense across the entire equatorial Pacific increasing dramatically the past 1-2 months (Fig. 6). During a conventional El Nino most of the upper ocean heat convenes east of the Dateline. The Climate Impact Company probabilistic ENSO forecast is stronger with El Nino ahead (Fig. 7) although initially the El Nino is likely biased toward Modoki and becomes a full-tilt El Nino in 2019 much like the El Nino of 1986-87. A review of El Nino 1986-87 in the Climate Impact Company Daily Feature is ahead. Fig. 1-2: Upper ocean heat maintains a very warm signature toward the Dateline. Recent westerly wind in the tropical East Pacific pushed some of that central Pacific warm water toward the northwest coast of So. America. Fig. 3: The 12-week Nino SSTA observations indicate El Nino warming. Fig. 4: The multivariate ENSO index indicates the atmosphere is beginning to respond to the ocean warming (again) with a marginal El Nino +MEI through September. Fig. 5: The Modoki index monitor indicates a possible trend back toward the positive phase initiating the past week or so. Fig. 6: The upper ocean heat indices across the entire equatorial Pacific are ALL impressively warm. This is a RARE signature. Fig. 7: Given the upper ocean heat a stronger El Nino ahead is forecast by Climate Impact Company.