A mature and strong El Niño was now present in the tropical Pacific Ocean, with the possibility to strengthen further before the end of the year, the World Meteorological Organization (WMO) said on Tuesday.
During August, east-central tropical Pacific Ocean surface temperatures have ranged between 1.3 and 2 Celsius degrees above average, exceeding El Niño thresholds by around one Celsius degree, indicating that the current El Niño was at a very significant level, WMO said.
During the last several months, temperatures below the surface of the tropical Pacific to the east of the international dateline have been substantially above average. This weather effect was in response to persistent episodes of significant weakening of the trade winds. The current excess subsurface heat had the potential to maintain or strengthen the above average sea surface temperatures in the coming months.
Models and expert opinion suggested that surface water temperatures in the east-central tropical Pacific Ocean are likely to exceed 2 degrees Celsius above average, potentially placing this El Niño event among the four strongest events since 1950.
WMO said the peak strength of this El Niño, expected sometime during October to January of next year. Impacts from this El Niño are already evident in some regions and will be more apparent for at least the next 4 to 8 months.
A careful watch will be maintained on the oceanic and atmospheric conditions over the tropical Pacific in the coming months to better assess the evolution of the strength of the event.
Historically, a mature El Niño event is likely to have maximum strength between October and January of the following year, and often to persist through much of the first quarter of that year before decaying.
WMO noted it was important to note that El Niño and La Nina are not the only factors that drive global climate patterns. At the regional level, seasonal outlooks need to assess the relative impacts of both the El Niño and La Nina state and other locally relevant climate drivers.