Current El Nio Ties 1997-1998 as Strongest on Record, Says NOAA
The current El Nio has tied the strongest previous El Nio on record, but appears to have peaked according to data just released this week by NOAA.
Sea-surface water temperatures in the equatorial central and eastern Pacific Ocean over the latest three-month period from October through December 2015 were 2.3 degrees Celsius above average, according to NOAA’s Climate Prediction Center. That departure from average, commonly referred to as the sea-surface temperature (SST) anomaly, ties the peak anomaly measured during the 1997-1998 El Nio, the strongest El Nio on record since recordkeeping began in 1950, according to NOAA’s Climate Prediction Center.
El Nio is an anomalous, yet periodic, warming of the central and eastern equatorial Pacific Ocean. For reasons still not well understood, every two to seven years, this patch of ocean warms for six to 18 months, then cools.
Examining finer-resolution monthly or weekly SST data from NOAA/CPC suggests the current El Nio either is peaking, or has already done so in November, respectively.
We should note that, for historical context, the most accepted method of categorizing the intensity of El Nios and their opposite, La Nias, utilize NOAA’s three-month running mean SST anomaly, known as the Oceanic Nio Index (ONI), instead of looking at one week or even one month’s worth of data.
Dr. Phil Klotzbach, tropical scientist at Colorado State University, noted heat content in the uppermost 300 meters of the equatorial Pacific Ocean east of the international date line has steadily declined since November. According to NOAA/CPC, this heat content typically hits a maximum before and during the early stages of an El Nio.
The latest model guidance suggests a typical weakening of El Nio through the spring, eventually disappearing by late spring or early summer. This means sea-surface water temperatures in the equatorial central and eastern Pacific Ocean will return to near-average levels from their current above-average state.
