The departures from the average sea surface temperature (SST anomaly) across most equatorial regions of the eastern and central Pacific Ocean have become mainly negative. During October, the Niño indices ranged from positive values in west-central Pacific, +0.1°C (Niño region Niño-4), to negative values across the central and easternmost Pacific, -0.3 °C (Niño regions: Niño-3.4 and Niño 1+2). The upper ocean heat content anomalies are below average and below-average subsurface temperatures have spread across the central Pacific. The atmosphere has also reflected this change where low-level wind anomalies were easterly over the central and eastern Pacific Ocean and the upper-level winds were westerlies. Collectively, the coupled ocean-atmosphere system reflects conditions of ENSO-neutral tending to borderline La Niña conditions. Climate models indicate with a moderate probability (57%) of weak La Niña conditions to develop November through December and continue January-February 2025.

What does this mean for Trinidad and Tobago?

The current ENSO-neutral event increases the likelihood of near-normal climatic conditions to occur. Historically during an ENSO-neutral event, near-normal rainfall amounts would occur within Trinidad and Tobago, but not always. The weak La Niña conditions expected should positively influence local and regional rainfall climatic systems and therefore possibly increase rainfall amounts through December 2024 into January 2025. 

Guide: A La Niña (El Niño) is declared when the average SSTs in the central and eastern equatorial Pacific Ocean become at least -0.5 °C cooler than average (0.5 °C warmer than average) in the preceding month and the cooling (warming) is expected to persist for five consecutive overlapping three-month periods. This must occur together with a corresponding change in the overlying atmospheric circulation. The TTMS La Niña/El Niño Watch is activated when the ENSO Outlook indicates a probability of approximately 50% chance or greater for the development of La Niña or El Niño.