What is a Super El Niño?
El Niño is a natural climate phenomenon characterized by the abnormal warming of sea surface temperatures in the equatorial Pacific Ocean. This warming disrupts global weather patterns, affecting rainfall and temperatures worldwide. When the warming is particularly intense, it's classified as a Super El Niño, an extreme event that can trigger severe floods, droughts, and other impacts.
According to the latest reports from the World Meteorological Organization (WMO) and Argentina's National Meteorological Service (SMN), the current El Niño is active and consolidated, with a 100% probability of persisting through the September-October-November 2026 quarter. It is expected to intensify to a "very strong" category, meaning a Super El Niño.
The RONI index (which measures the phenomenon's intensity) is projected to reach 3.5 between October 2026 and January 2027. For context, a value of 2.0 already indicates very strong conditions, and the historical record was 2.4 during the 1982-83 event.
The WMO warns the phenomenon will last at least until February 2027, meaning its effects will be felt throughout the summer and into early autumn.
Where Will It Rain Most in Argentina?
The impact won't be uniform across the country. The areas expected to see the most significant rainfall anomalies are:
- Northeast and Litoral (Corrientes, Misiones, Chaco, Formosa): The largest anomalies are expected here, with accumulations of 150 to 200 mm in September (normal is 120-150 mm), and some locations could exceed 300 mm.
- Central and Pampas region (eastern Buenos Aires, central Argentina): Rainfall will be near normal or slightly above, but intense storms and saturated soils are being closely monitored.
- Cuyo and Patagonia: Accumulations are expected to be normal or below average, with water deficits toward the west and southern Patagonia.
- San Luis: Up to 200 mm is projected for the quarter (vs. 150 mm normal), with a greater than 50% probability of precipitation exceeding 100-150 mm in the east, south, and center of the province. Temperatures will also be higher than normal, with averages of 22°C in September, 25°C in October, and 28°C in November.
Risks: River Flooding, Waterlogging, and Urban Pressure
The main danger is the overflow of the Paraná, Paraguay, Uruguay, and Iguazú rivers, due to intense rains upstream in Brazil and Paraguay. This could cause flooding and waterlogging in riverside areas, ports, roads, and productive zones.
In the AMBA (Greater Buenos Aires), frequent and intense rains will increase pressure on storm drains, with a risk of urban flooding. Authorities recommend constant monitoring of short-term forecasts and early warnings.
For the agricultural sector, the impact won't be uniform: excess water will be concentrated in specific areas and basins, so it's recommended to plan planting and harvesting activities with attention to daily reports.
Temperatures: No Extreme Heat Waves, but with Nuances
In general, no widespread extreme heat waves are anticipated at the start of the quarter. Average temperatures will be normal or slightly cooler in the central part of the country. However, in San Luis and other western areas, values are expected to be above normal, which could increase the heat index.
International Impact: Hurricanes and Drought in Panama
The Super El Niño doesn't only affect Argentina. In Mexico, Hurricane Marie (Category 2) has intensified due to the phenomenon, and 18 to 21 cyclones are forecast in the Pacific during the season. In Panama, drought has forced a reduction in ship transits through the Panama Canal from 36 to 32 daily crossings starting September 15.
These figures reflect the global magnitude of the event, requiring international cooperation and local preparedness.
Recommendations for the Public
- Stay informed through official SMN channels and emergency agencies.
- In riverside areas, be alert to river levels and evacuation warnings.
- In urban areas, do not throw waste into the streets to avoid clogging drains.
- For agriculture, consult weekly agrometeorological reports and adjust management practices.
Source: La Gaceta and data from the National Meteorological Service.