The South region will have a cold wave and strong frosts in the coming days

According to the National Institute of Meteorology (Inmet), in the coming days, the Southern Region of Brazil will have lower temperatures and heavy frosts. This condition occurs due to the passage of a cold front, between Friday (28) and Saturday (29), accompanied by a strong and large air mass of polar origin, combined with cold and dry air. The most affected states will be Rio Grande do Sul and Santa Catarina, in addition to southern Paraná.

Also according to Inmet, the change in direction and intensification of winds, which began late Friday until Sunday (30), will cause low thermal sensation and accentuate the cold in all areas of the south of the country.

Rain and drop in temperatures

During the passage of the cold front, the formation of areas of instability may cause rain (figure 1a) in the northern half of Rio Grande do Sul, especially between Santa Catarina and Paraná on Saturday (29).

The forecast still shows a lot of humidity in the north of Rio Grande do Sul and Santa Catarina (figure 2a) during the passage of the cold front. On Saturday (29), as it traveled through Paraná, humidity concentrated in the state (figure 2b).

In addition to the rain and humidity, winds in the eastern part of the state of Rio Grande do Sul, blowing from west to south, will accentuate the cold and should also help to dam up Lake Guaíba until Sunday (30), as shown in figure 3.

Temperatures and frosts

Inmet's forecast is for temperatures between 0°C and 5°C in the early morning hours, starting on Saturday (29) until at least Monday (1/7). There is a possibility of negative temperatures between 0°C and -5°C in areas of the campaign and, mainly, in the mountains of Rio Grande do Sul, Santa Catarina and southern Paraná (figure 4).

The frosts, in turn, will begin between the night and dawn in the coldest areas on Sunday (30th) and Monday (1st). Still on the 1st, the forecast shows intense cold in the low-lying areas. Inmet does not rule out the possibility of frost between Tuesday (2) and Wednesday (3).

Inmet emphasizes that the frost must be widespread, with moderate to very strong intensity (figure 5). On Sunday (30), the phenomenon will be of strong to very strong intensity between the mountains of Rio Grande do Sul and Santa Catarina, in the extreme south of Paraná and in the Campanha Region, in the west of Rio Grande do Sul.