Brazilian weather authorities and others issued a joint report on El Niño on September 30.
The report found that even within the same country, drought and wildfire risks could rise in the central and northern regions, while the southern regions could face heavier rain and a greater risk of flooding.
This is why forecasts of a strengthening El Niño alone cannot establish that weather will move in one direction across every region.
3-Line Summary
1. El Niño’s effects vary by region in Brazil
2. Drought in the central and northern regions, and heavier rain in the south, are forecast
3. Seasonal forecasts differ from actual weather by region
From October to December, 95% Chance of “Very Strong” Conditions
Report No. 4, jointly issued by Brazil’s National Institute of Meteorology (INMET) and several federal agencies, put the likelihood of El Niño reaching a very strong level between October and December at 95%. El Niño is the phenomenon in which abnormal warming of the surface waters of the equatorial Pacific changes the flow of winds and rain.
According to the report, sea-surface temperature anomalies in the central and eastern equatorial Pacific exceeded 2℃ at the end of September. El Niño conditions were confirmed in June, and its effects were forecast to continue at least through the first quarter of 2027. However, this is a forecast showing seasonal trends; it does not indicate when rain will fall or drought will end in a specific city.
Less Rain in the Central and Northern Regions, Excess Rainfall in the South
The key point presented in the joint report is the contrast between two risks in Brazil. In the central and northern regions, a continuing lack of rain and high temperatures could increase the risk of drought and wildfires, while in the south, heavier-than-normal rain could raise the risk of rivers overflowing. The forecast also included the possibility that temperatures could be above the normal range across nearly the entire country.
Worsening drought has already appeared in some indicators. In Cemaden’s partial September tally, the number of municipalities experiencing extreme drought rose from 4 to 24 in one month, while the number experiencing severe drought increased from 153 to 197. The largest increases were seen particularly in the states of Amazonas, Bahia, Amapá, Alagoas, and Sergipe.
In the Northeast, 16% of the region was recorded as experiencing severe drought. Drought also worsened rapidly in the northern states of Roraima, Acre, and Amazonas, and the report said that some municipalities were experiencing difficulties with water extraction and navigation. The Branco and Negro rivers in Roraima were mentioned as having low water levels.
In the south, meanwhile, heavy rain raised river levels and caused flooding. The Taquari Valley and areas around the Caí River in Rio Grande do Sul, as well as several municipalities in Santa Catarina, were cited as major affected areas. Brazil’s Geological Survey (SGB) issued more than 190 hydrological alerts in southern regions in 2026.
Agriculture Also Varies by Region Rather Than by Crop Alone
The agricultural effects of El Niño are also difficult to assess based on the name of a single crop. Researchers at the University of São Paulo explained that soybeans in northern Mato Grosso could be affected by reduced rainfall, while soybeans in Rio Grande do Sul and Paraná could benefit from the possibility of increased rain.
A lack of rain and heat in the central and northern regions could burden soybeans, coffee, and livestock in semiarid areas. In the south, moisture could benefit corn, but excessive rain could increase disease in wheat and make it difficult to plant soybeans and rice. This is why the single phenomenon known as El Niño does not immediately mean a nationwide bumper harvest or poor harvest.
The most important point to watch in this report is the direction of regional risks, rather than the phrase “strong El Niño.” Seasonal forecasts can provide a basis for prevention and preparedness, but the actual effects may vary depending on subsequent changes in weather and hydrological conditions.
References
Tags #ElNiño #BrazilWeather #BrazilDrought #BrazilFlooding #ClimateCrisis #ExtremeWeather #PacificSeaSurfaceTemperature #SeasonalForecast #WildfireRisk #HeavyRain #AgriculturalWeather #INMET