Bob Tisdale writing at Watts Up With That has an update:
INTRODUCTION – NINO3.4 SEA SURFACE TEMPERATURE ANOMALIES ARE AT THE 1.5 DEG C THRESHOLD OF A STRONG EL NIÑO
NOAA defines a Strong El Niño as: “Episode when the peak Oceanic Niño Index (ONI) is greater than or equal to 1.5°C.” (See the footnotes of the NOAA ENSO blog post here.) And NOAA’s Oceanic Niño Index is a three-month running average of NINO3.4 sea surface temperature anomalies.
Weekly NINO3.4 sea surface temperatures for the week centered on July 8, 2015 are at 1.5 Deg C, the threshold a strong El Niño. Of course, the running 3-month average of the monthly NINO3.4 sea surface temperature anomalies would have to remain at or above that threshold for a number of months in order to register as a strong El Niño on NOAA’s Oceanic NINO Index.
More details HERE.