A powerful extratropical cyclone developing off the coast of Argentina is set to unleash a wave of severe weather across southern Brazil in the coming days. The system, a low-pressure area formed by contrasting air masses, will not make direct landfall in Brazil but will still deliver significant impacts, including strong winds, heavy storms, and a sharp drop in temperatures.
The cyclone is expected to intensify near the coast of Buenos Aires starting Thursday. While the core of the system will remain over the Atlantic Ocean, with winds potentially reaching 180 km/h in open waters, its associated cold front will push into Brazil. This front will bring rain, sometimes heavy to intense, and a risk of severe weather, including possible gales with gusts exceeding 100 km/h in some areas of the South region.
Even before the cold front arrives, strong winds are forecast for Thursday across the three southern states, Mato Grosso do Sul, and the interior of São Paulo. These warmer, drier winds could cause gusts between 70 km/h and 90 km/h in parts of Rio Grande do Sul, with some locations experiencing even higher speeds. The instability will intensify Thursday afternoon in Rio Grande do Sul, with the possibility of heavy rain, isolated hail, and gusts surpassing 90 km/h.
The cold front associated with the cyclone will begin entering western Rio Grande do Sul Thursday night and advance across the South region and into Mato Grosso do Sul on Friday. The forecast calls for rain and a risk of severe weather. By the weekend and early next week, the front's effects will extend to Mato Grosso, Rondônia, São Paulo, and Rio de Janeiro, with gusts potentially reaching 80 km/h between São Paulo and Rio de Janeiro on Sunday.
Following the storm system, a strong polar air mass is forecast to invade Brazil over the weekend, bringing what is expected to be the most significant temperature drop of the year so far. The cold air is predicted to start entering the country from the extreme south on Friday, gaining strength on Saturday and Sunday. It will spread rapidly through the South, Southeast, and Center-West regions, with effects reaching even into western Amazonia.
The coldest mornings are anticipated between Sunday and Tuesday. In the southern states, minimum temperatures are expected to range between 0°C and 5°C in many municipalities, with the possibility of negative readings in various locations. In higher altitude areas, thermometers could drop to -5°C. Widespread frost is also expected, posing a potential risk to agriculture.
Specific capital forecasts highlight the coming chill: Porto Alegre is expected to see lows near 9°C on Sunday, Curitiba around 6°C on Monday, and São Paulo dropping to about 10°C by Tuesday. Even Rio de Janeiro will feel the change, with temperatures falling to near 20°C on Monday. The system's influence will also be felt in the Center-West, with Campo Grande forecast to reach a low of 9°C on Sunday.
Based on reporting from g1.