The Instituto Nacional de Meteorologia (Inmet) predicts temperatures will reach or exceed 40°C across much of Brazil this weekend [1].

These extreme conditions pose significant health risks to the population and create volatile weather patterns that can lead to sudden, severe atmospheric disturbances.

In the city of Rio de Janeiro, meteorologists expect a maximum temperature of 39°C on Saturday [1]. The heat is projected to intensify further, reaching 40°C on Sunday and Monday [1]. These high temperatures are driven by high-pressure conditions that keep the weather stable and hold heat over the region [1].

While much of the country deals with rising temperatures, the state of Rio Grande do Sul is under a severe heat alert [1]. The region is preparing for a complex weather shift as a new cold front approaches. This front is expected to bring storms to the southern state, contrasting with the intense heat currently affecting the area [1].

Inmet said that the combination of high-pressure systems and the arrival of cold fronts often triggers these temperature extremes. The agency continues to monitor the movement of the front to provide updated warnings for the southern region [1].

“Temperatures are expected to hit 40°C in Rio de Janeiro.”

The simultaneous occurrence of a severe heatwave and an approaching cold front indicates high atmospheric instability. When intense heat meets a cold front, it often results in more violent storm systems, increasing the risk of flash flooding and infrastructure damage in southern Brazil.