COLLEGE PARK, Maryland, U.S. – During August, ENSO neutral continued as reflected by near-average sea surface temperatures (SST) across most of the central and eastern equatorial Pacific Ocean, according to a report issues by the Climate Prediction Center/Ncep/Nws and the International Research Institute for Climate and Society, which are a part of the National Oceanic and Atmospheric Administration‘s National Weather Service.
The latest weekly Niño-3 and Niño-3.4 indices were -0.2°C and 0.0°C, respectively, with the westernmost Niño-4 region index remaining above average (0.5°C) and the easternmost Niño-1+2 region index remaining below average (-0.6°C). Upper-ocean subsurface temperature anomalies (averaged across 180°-100°W) decreased slightly during the month, with below-average temperatures strengthening in the east-central equatorial Pacific.
Suppressed tropical convection continued over parts of Indonesia, while near-average convection was evident near the Date Line. Low-level and upper-level winds were near average over most of the tropical Pacific Ocean. Overall, oceanic and atmospheric conditions were consistent with ENSO-neutral.
The majority of models in the IRI/CPC plume continue to favor ENSO-neutral (Niño-3.4 index between -0.5°C and +0.5°C) through the Northern Hemisphere spring. Interestingly, the statistical model averages favor Niño-3.4 values above the El Niño threshold (+0.5°C) during the fall and winter, while the dynamical model average indicates values near +0.2°C.
Forecasters are leaning toward the dynamical model average, which is also supported by the current tendency of the ocean toward cooler conditions. In summary, ENSO-neutral is favored during the Northern Hemisphere fall 2019 (~75% chance), continuing through spring 2020 (55-60% chance).