The formation of an extratropical cyclone in the Southern region of the country this Thursday, the 20th, is expected to generate warnings for intense rainfall and strong winds. This system tends to move towards the ocean, aiding in the structuring of a cold front.
This climatic shift may pave the way for the arrival of a polar air mass. Projections indicate a sharp reduction in temperatures in the South-Central area starting on Friday, the 21st, with the thermal drop extending to the interior of the Northern region over the weekend.
On Thursday, very unstable weather is expected in the three southern states, with risks of thunderstorms, hail, and wind gusts of up to 90 km/h. In Rio Grande do Sul, precipitation volume could reach 80 millimeters in parts of the West, Campanha, and South. Predicted highs are 21°C in Porto Alegre (RS) and 27°C in Curitiba (PR).
Starting Friday, the advance of polar air may cause temperature drops, with a probability of frost and negative readings between Saturday (22) and Sunday (23).
Meanwhile, on Thursday, much of the Southeast region should experience heat and dry weather. Temperatures could reach 32°C in São Paulo (SP) and Rio de Janeiro (RJ), 31°C in Belo Horizonte (MG), and exceed 35°C in the interior of São Paulo. Winds are expected to intensify between Thursday night and Friday due to the approach of the cold front. Rain may concentrate on the São Paulo coast, the Paraíba Valley, and the Mantiqueira Range, with a forecast cooling down over the weekend.
Mato Grosso do Sul should be the first state to feel the climatic change, with a predicted temperature drop already on Thursday, accompanied by winds of up to 60 km/h and a high of 23°C in Campo Grande (MS). Cold air also has the potential to reach southern Mato Grosso. In Goiás and the Federal District, the scenario tends to remain stable, characterized by intense heat and low air humidity.
Rain showers should be located along the coastal strip, especially between Rio Grande do Norte and Sergipe. The largest accumulations may occur on the coast of Pernambuco and Alagoas, while the northern coast may record wind gusts of up to 70 km/h. In the interior of the Northeast, hot and dry weather should persist.
Polar air should progress through the region, reaching Acre, Rondônia, and southern Amazonas. The forecast points to cold spells, with the effect of the temperature drop being most noticeable during the night and early morning. In other areas of the North, heat should remain predominant, with dry weather expected for Pará and Tocantins. There is a possibility of isolated rains in Amazonas, Roraima, Amapá, and northern Pará.