WMO El Niño/La Niña Update
15 April 2014
Current Situation and Outlook
The tropical Pacific continues to be ENSO-neutral (neither El Niño nor La Niña). Model forecasts and expert opinion suggest that neutral conditions are likely to continue into the earlier part of the second quarter of 2014. However, temperatures below the surface of the tropical Pacific have warmed to levels that can occur prior to the onset of an El Nino event, while climate models surveyed by WMO experts show a steady warming of the tropical Pacific during the months ahead. A majority of models reach El Niño thresholds around the middle of the year. If an El Niño event does occur, it remains too early to determine its strength. National Meteorological and Hydrological Services and other agencies will continue to monitor Pacific Ocean conditions for further El Niño developments, and will assess the most likely local impacts.
Since the second quarter of 2012, El Niño-Southern Oscillation (ENSO) indicators in the tropical Pacific (e.g., tropical Pacific sea surface temperatures, sea level pressure, cloudiness and trade winds) have generally remained at neutral levels, indicating that neither El Niño nor La Niña conditions have been present.
The latest outlooks from climate models and expert opinion suggest that oceanic conditions and atmospheric anomalies associated with El Niño or La Niña are most likely to remain neutral into the earlier part of the second quarter of 2014. However, since February there have been two strong westerly wind events, and a general weakening of trade winds in the tropical Pacific. This has led to a significant warming of the waters below the surface of the central Pacific, which historically has been a precursor to El Niño development. While there is no guarantee this situation will lead to an El Niño event, the longer the trade winds remain weakened, and subsurface temperatures stay significantly warmer than average, the higher the likelihood of the emergence of an El Niño.
Model forecasts indicate a fairly large potential for an El Niño, most likely by the end of the second quarter of 2014. For the June to August period, approximately two-thirds of the models surveyed predict that El Niño thresholds will be reached, while the remaining models predict a continuation of neutral conditions. A few models predict an earlier El Niño onset, such as in May. No model suggests a La Niña in 2014. The strength of the possible El Niño cannot be reliably estimated at the current time. This uncertainty is related to the fact that model outlooks that start in March-April tend to have lower skill than those made later in the calendar year, due to the more fluid nature of the ocean-atmosphere system during March to June. If El Niño does develop by the end of the second quarter of 2014, it is likely to continue through the remainder of the year.
It is important to note that El Niño and La Niña 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/La Niña state and other locally relevant climate drivers. For example, the state of the Indian Ocean Dipole, or the Tropical Atlantic SST Dipole, may impact the climate in the adjacent land areas. Locally applicable information is available via regional/national seasonal climate outlooks, such as those produced by WMO Regional Climate Centres (RCCs), Regional Climate Outlook Forums (RCOFs) and National Meteorological and Hydrological Services (NMHSs).
The situation in the tropical Pacific and Indian Ocean will continue to be carefully monitored. More detailed interpretations of regional climate variability will be generated routinely by the climate forecasting community over the coming months and will be made available through the National Meteorological and Hydrological Services. For web links of the National Meteorological Hydrological Services, please visit:
|© World Meteorological Organization, 7bis, avenue de la Paix, Case postale No. 2300, CH-1211 Geneva 2, Switzerland - Tel.: +41(0)22 730 81 11 - Fax: +41(0)22 730 81 81 Contact us|