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A cyclonic vortex will act over the Central-South of Brazil throughout Holy Week, bringing intense rains that should put an end to the extreme heat of recent weeks, while weather models already indicate the advance of a cold air mass from Argentina, Uruguay, and the South of Brazil between Thursday and April 6, with a significant drop in temperatures.
The intense heat that has battered Brazil in recent weeks is numbered. A cold air mass is already appearing in weather models, with forecasts of advancing through Argentina, Uruguay, and the South of Brazil between next Thursday and April 6, promising to lower the temperatures that have been breaking records in various states. Before that, a cyclonic vortex at high levels will act over the Central-South of the country throughout Holy Week, bringing intense rains that are already beginning to weaken the warm air mass.
The weather change has a defined schedule. According to Meteored’s forecast, the instabilities will begin this Monday (30) on the coast of Santa Catarina and in the northeast of Rio Grande do Sul, with heavy clouds forming over the ocean. Throughout the week, the rains will advance to Paraná, São Paulo, Rio de Janeiro, Minas Gerais, and Mato Grosso do Sul, progressively weakening the heat. And when the cyclonic vortex loses strength on Thursday, the cold air mass coming from the south should take control of the atmospheric conditions, marking the end of the heat wave and the beginning of the first real signs of autumn.
The cyclonic vortex that will change the weather during Holy Week
The protagonist of the first phase of the change is a High-Level Cyclonic Vortex (VCAN) that will act over the Central-South of Brazil throughout Holy Week. This atmospheric system works like a low-pressure whirlwind in the upper layers of the atmosphere, pulling moisture and generating instability over a wide area of Brazilian territory.
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Starting this Monday, the cyclonic vortex begins to show its effects on the coast of Santa Catarina and in the northeast of Rio Grande do Sul. Heavy clouds are expected to advance across the eastern strip of both states, from northern Santa Catarina to the Porto Alegre region.
On Tuesday (31), the system intensifies and the rains will also reach Paraná, São Paulo, Rio de Janeiro, Minas Gerais, and Mato Grosso do Sul. As a result, the winds will change direction and the warm air mass that sustained the extreme heat will lose strength.
On Wednesday (April 1), the intense rains will remain concentrated mainly between Paraná and São Paulo. The cyclonic vortex enters its last day of action on Thursday (2), favoring a better distribution of rains over the Central-South of the country and making way for the cold air mass forming in the south to begin advancing over Brazilian territory.
Where the intense rains will be strongest during Holy Week
Meteored has issued alerts for intense rains and storms over a wide area of Southern Brazil and parts of the Southeast and Midwest. The areas with the highest risk of heavy precipitation are concentrated between Santa Catarina and Paraná, where the cyclonic vortex is expected to cause the largest volumes of rain throughout Holy Week.
On Thursday (2), the alert extends to the north of Rio Grande do Sul, all of Santa Catarina and Paraná, the central-south of Mato Grosso do Sul, areas of northern, central, eastern, and southern São Paulo, southern Rio de Janeiro, and the central-south and west of Minas Gerais.
This is the most intense phase of the cyclonic vortex’s action, when the intense rains cover the largest territorial extent.
For Southern Brazil, the rains represent both relief and risk. The relief comes from the end of the extreme heat that has plagued the region in recent weeks.
The risk comes from the volume of precipitation: concentrated rains in a few hours can cause flooding, landslides, and disruptions in urban areas, especially in cities that already face drainage problems. The recommendation is to monitor local weather alerts throughout Holy Week.
When the cold air mass arrives and how far it will drop temperatures
The second phase of the weather change is of interest to those waiting for the real end of the heat. According to Conexão Geoclima, weather models have begun to indicate the possibility of the advance of a cold air mass through Argentina, Uruguay, and the South of Brazil between Thursday (April 3) and April 6. If the forecast is confirmed, temperatures could drop significantly in Rio Grande do Sul, Santa Catarina, and Paraná, the first concrete signs that autumn has truly arrived.
The scenario is still being defined, but the trend is consistent across various atmospheric models. The cold air mass forming over Argentine Patagonia is being pushed by a migratory anticyclone moving from southwest to northeast.
Upon entering Southern Brazil, this mass will lower maximum and minimum temperatures, potentially bringing thermometers to levels well below what was recorded in recent weeks when cities in Rio Grande do Sul and Santa Catarina exceeded 36°C.
The remaining question is about the intensity. A moderate cold air mass brings mild and pleasant temperatures, typical of autumn.
A more intense cold air mass could cause lows near 10°C or below in mountainous areas and the interior of Rio Grande do Sul and Santa Catarina something that, after weeks of extreme heat, would represent a considerable thermal shock. The next few days will determine which scenario prevails.
The end of the heat wave and what to expect for April in Southern Brazil
The combination of the cyclonic vortex during Holy Week with the advance of the cold air mass in the first week of April marks the end of a heat period that was notable for its duration and intensity.
The last weeks recorded temperatures well above average for the end of March in practically all of Southern Brazil, with the thermal sensation exceeding 40°C in various cities.
The trend for April is for a gradual normalization. Cold air masses should become more frequent, alternating with periods of milder heat, the typical autumn pattern in the region.
But the transition will not be smooth: the shift from an extreme heat to the arrival of polar cold air can cause temperature variations of more than 15°C in just a few days, requiring attention to health and clothing.
For those monitoring the weather in Southern Brazil, Holy Week 2026 will be marked as the turning point. The cyclonic vortex brings the intense rains that end the heat, and the cold air mass right behind confirms that the extended summer has finally ended.
After weeks of enduring temperatures above 35°C, relief comes first in the form of rain, then in the form of cold.
With information from the portal NDMAIS.
Are you waiting for the cold or would you prefer the heat to continue? How is the weather in your city right now? Let us know in the comments; we want to know if the change has already arrived in your region or if the heat is still holding on.
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