According to the latest report from the National Weather Service and the International Research Institute for Climate and Society released on Sept. 12, 2019, conditions are 75% that a weather pattern marked by average long-term ocean temperatures, tropical rainfall and atmospheric winds will prevail in the Northern Hemisphere this fall.
The report also finds the probability that the El Niño-Southern Oscillation-neutral (ENSO) weather pattern will continue through the spring of 2020 is 55% to 60%.
ENSO stands for El Niño/Southern Oscillation. The ENSO cycle refers to the coherent and sometimes very strong year-to-year variations in sea-surface temperatures, convective rainfall, surface air pressure, and atmospheric circulation that occur across the equatorial Pacific Ocean. El Niño and La Niña represent opposite extremes in the ENSO cycle.
El Niño refers to the above-average sea-surface temperatures that periodically develop across the east-central equatorial Pacific. It represents the warm phase of the ENSO cycle, and is sometimes referred to as a Pacific warm episode.
La Niña refers to the periodic cooling of sea-surface temperatures across the east-central equatorial Pacific. It represents the cold phase of the ENSO cycle, and is sometimes referred to as a Pacific cold episode.
ENSO-neutral conditions refer to those periods in which neither El Niño nor La Niña are present, often coinciding with the transition between the 2 weather patterns. Click or tap here to read more about these patterns and how they affect weather across the globe.
During August, ENSO-neutral continued as reflected by near-average sea surface temperatures across most of the Central and Eastern equatorial Pacific Ocean. 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 and the easternmost Niño-1+2 region index remaining below average.ensodisc