Brazil is facing a new heat wave, which is expected to last until next Friday (15/3). This is the third in 2024, and will affect areas of Mato Grosso do Sul, São Paulo, Paraná, Santa Catarina and Rio Grande do Sul. According to the National Institute of Meteorology (Inmet), in these states, maximum temperatures should remain 5°C above average; Therefore, a “danger alert” was issued.
According to the agency, the alert is valid until the end of the heat wave. The warning of above average temperatures came into effect this Monday (11/3). In some places, temperatures can reach 40°C.
On Monday afternoon, Campo Grande (MS) recorded the highest temperature of the year so far: 35.8ºC.
Atmospheric blocking and El Niño
According to Fábio Luengo, meteorologist at Climatempo, the current heat wave is the result of an atmospheric blockage that prevents the advance of cold fronts across the country, allowing the hot air in central Brazil to gain strength, increasing the heat.
The system also makes it difficult for clouds to form and keeps the air dry and gradually warming. According to him, heat waves are common at this time of year, however, they tend to be more restricted to the south.
This year, the new heat wave would be explained by the El Niño phenomenon. Data from the American Oceanic and Atmospheric Agency (NOAA) indicate that the temperature of the Central-Eastern Equatorial Pacific remains at moderate El Niño levels.
And, despite having passed its peak at the end of last year and ending in a few weeks, El Niño still influences the climate in Brazil. Luengo points out that the phenomenon should only change and reach neutrality in mid-April.
Heat
According to Climatempo, the forecast indicates that this hot air mass should expand to the Triângulo Mineiro, the entire state of São Paulo, Goiás, Mato Grosso, Distrito Federal, Rondônia, Roraima and part of the states of Acre, Amazonas, Pará , Tocantins and Bahia.
Unlike a heat wave (which has technical terms that characterize it), these regions should experience intense heat until Friday (15/3), with temperatures around 3ºC to 5ºC above average.
Inmet notices
The term “heat wave” is used when there is a temperature increase of 5ºC in relation to the monthly average. When this pattern persists for two to three consecutive days, Inmet issues a “potential danger” alert, the so-called yellow warning.
When this pattern persists for three to five consecutive days, the institute issues a “danger” alert, the so-called orange warning, like the one that affects a large part of the Center-South region throughout this week.
Finally, when this pattern persists for more than five consecutive days, Inmet issues a “great danger” alert, the so-called red warning. In November, a similar alert was issued by Inmet.