Brazil faces weather contrasts: from 41°C to thunderstorms this week

A bomb cyclone continues to influence the weather in Southern Brazil during this Friday (7) and Saturday (8). Inmet issued an alert predicting storms, potential hail, and wind gusts in various locations in the region.

After the passage of this meteorological system, the climate scenario will undergo rapid changes. The cold will intensify in Rio Grande do Sul, increasing the risk of frost and causing a drop in temperatures. Additionally, much of the country's interior will continue to face concerns about low air humidity.

The forecast provided by Inmet indicates that the extratropical cyclone, which is rapidly intensifying, still affects the South of the country and also generates instability in southern Mato Grosso do Sul and parts of São Paulo.

Main points of the forecast

The period of greatest climatic attention remains focused on Paraná and Santa Catarina. In these states, intense rainfall, thunderstorms, strong winds, and the possibility of hail are expected throughout Friday.

On the other hand, Rio Grande do Sul will begin to register a progressive improvement in atmospheric conditions. Precipitation will decrease in intensity, paving the way for the arrival of a strong cold air mass.

While Paraná and Santa Catarina persist with instability, Rio Grande do Sul will have a weekend characterized by cold.

On Saturday (8), stable weather will contribute to a sharp reduction in temperatures, particularly in the south-central region of the state, where thermometers may approach 0°C. In these areas, conditions are also favorable for the formation of frost.

In Porto Alegre, the minimum predicted temperature is 5°C, and the maximum should not exceed 15°C.

In regions outside the area impacted by the cyclone, the climate picture shows little variation. A large portion of the Center-West, Southeast, and Matopiba region maintains low relative humidity levels, keeping the alerts issued by Inmet.

Rain will remain concentrated mainly over western Amazonia and segments of the Northeast coast. In other inland areas, the weather tends to be stable.

The National Institute of Meteorology (INMET) is monitoring the formation of a strong extratropical cyclone located between Argentina, Uruguay, Southern Brazil, and the Atlantic Ocean. This system has the potential to generate storms, wind gusts, hail, and decreasing temperatures in the coming days.

The classification of this event as a 'bomb cyclone' still awaits the evolution of atmospheric pressure. Forecasts indicate that the period requiring the most attention should be between Thursday, the 6th, and Saturday, the 8th, with a special focus on the Southern Region.

It is important to clarify that the name 'bomb cyclone' does not refer to an explosion; it describes an extratropical cyclone that rapidly gains strength due to a sharp drop in pressure at its center. This process is known as explosive cyclogenesis and generally occurs when air masses with distinct characteristics meet.

The encounter between warm, humid air and cold air facilitates the creation of a low-pressure zone that can intensify rapidly. According to INMET, the system will begin to structure itself from a low-pressure area located between northern Argentina and Paraguay, subsequently progressing towards Uruguay and the coast of Rio Grande do Sul.

The projection indicates that the cyclone may reach its most vigorous phase on Saturday, the 8th, with an estimated central pressure of 940 hPa, before gradually moving into the South Atlantic. Even if the core of the system is over the ocean, the effects can reach the continent due to the associated cold front and instability zones.

Among the predicted impacts, the strongest winds are expected to occur over the Atlantic Ocean, potentially exceeding 100 km/h near the cyclone's center. On the coast and in parts of Southern Brazil, notably in Rio Grande do Sul and Santa Catarina, gusts exceeding 60 km/h are expected.

Although extratropical cyclones are frequent in areas where warm and cold air masses converge, only some demonstrate sufficient acceleration to be classified as bomb cyclones. The crucial factor to observe is the speed at which the system evolves, as abrupt changes in pressure reduce the preparation time for facing strong winds, storms, and climate changes.

After the cyclone passes, a high-pressure area is expected to promote the arrival of a cold air mass over Central-South Brazil, resulting in a drop in temperatures in the following days. INMET continues to issue meteorological alerts for the Central-South areas and advises the population to follow forecast updates, as the trajectory and intensity of the system may be adjusted based on new data.