ENSO Watch Update (based on the NINO 3.4 index (120-170W, 5S-5N))
ISSUED AT: 03:00 PM
Date: Monday 26th of November 2018
El Niño Watch Continues: El Niño Conditions More Than Likely By The End 2018 November to December, 2018
The El Niño–Southern Oscillation (ENSO) continued in neutral state - neither El Niño nor La Niña - during October to November. However, the development of an El Niño pattern before the end of 2018 remains highly possible as sea surface temperatures (SSTs) in the Niño 3.4 region continue to warm. At present, SST departures from average in the Niño 3.4 region are positive and at El Niño levels, while subsurface waters also continue to be much warmer than average. However, the atmosphere has not responded fully. The chance of El Niño conditions during November to February is now at 83% but falls to 80% during December to March. Most international climate models continue to predict warming to persist in the coming weeks. Accordingly, the TTMS’s ENSO monitor remains in El Niño Watch.
What does this mean for Trinidad and Tobago?
El Niño during the late wet season and early dry season typically means suppression of rainfall in Trinidad and Tobago, leading to rainfall deficits during these periods. At the same time, daytime temperatures tend to be warmer than average, especially during the early dry season. Generally, potential effects of El Niño on Trinidad and Tobago include: reduced rainfall, warmer temperatures, shift in temperature extremes, reduced tropical cyclone activity in waters east of Trinidad and Tobago, and increased incidences of bush fires.
Guide: El Niño is declared when average SSTs in a region of the central and eastern equatorial Pacific known as the Niño 3.4 region become at least 0.5oC warmer than average in the preceding month and the warming is expected to persist for five consecutive overlapping three month periods. This must be in concurrence with the atmosphere in the Niño 3.4 region responding by weakening the trade-winds, while reducing rainfall and thunderstorm activity over the western equatorial Pacific Ocean and increasing it over the eastern half of the tropical Pacific Ocean. The TTMS El Niño/La Niña Watch is activated when the ENSO Outlook indicates a probability of approximately 50% chance or greater for development of El Niño or La Niña.