Severe weather warnings have been issued across Rio Grande do Sul as the region braces for extreme rainfall and potential flooding. On Thursday, May 8, 2025, the Instituto Nacional de Meteorologia (Inmet) declared a red alert for several areas, anticipating significant rain due to an approaching cold front combined with warm, humid air masses.
The Campanha region and surrounding municipalities are expected to face the brunt of the storm, with rainfall totals ranging from 60 mm to upwards of 100 mm. Some areas may even see precipitation exceed 100 mm, accompanied by wind gusts that could reach over 100 km/h. This precarious weather situation is set to persist until Friday, May 9, 2025.
According to forecasts, Uruguaiana is projected to receive a staggering 201 mm of rain in just one day, nearly double the monthly average for May, which is 118 mm. Similarly, Quaraí is expected to experience 167 mm, exceeding its average of 119 mm for the month. Such extreme rainfall is anticipated to lead to flooding and river overflows, particularly in the western, central, and Campanha regions.
MetSul Meteorologia has raised alarms about potential flooding, warning that rainfall accumulations in some cities could reach between 100% and 200% of the historical average for the entire month within a mere 48 hours. "The situation is severe, with the potential for hail, winds exceeding 90 km/h, and microbursts—localized events with intense wind gusts over short periods," the agency noted.
On Thursday, rainfall is expected to be most intense in the western and southern parts of the state, with cities like Uruguaiana, Quaraí, and Barra do Quaraí seeing the highest totals. For instance, Uruguaiana is anticipated to receive 201 mm, while Quaraí may see 167 mm and Barra do Quaraí about 138 mm. Other cities like São Gabriel and Rosário do Sul are also on alert as they prepare for significant rain.
The situation is exacerbated by a strong mass of dry air established over the central region of Brazil, which has been blocking the advance of cold fronts toward the Southeast and Central-West. This has resulted in a buildup of instability in the southern regions, leading to the formation of heavy rain clouds as the cold air interacts with the warm, humid air present in the state.
As the weather system progresses, the forecast indicates that rainfall accumulations will shift to the south and center of the state by Friday, with São Lourenço do Sul expected to receive up to 191 mm, Camaquã 175 mm, and Arambaré 163 mm. The heavy rains are projected to continue through the weekend, although a cooler air mass is expected to move in, potentially reducing overall precipitation.
In the Southeast region, isolated showers are predicted for Espírito Santo, while the rest of the states in the region are expected to have stable weather. For example, Rio de Janeiro is forecasted to reach a high of 32°C, while São Paulo will see a maximum of 29°C.
As the rain continues to fall, authorities are urging residents in affected areas to take precautions. The Defesa Civil has advised individuals to avoid flood-prone areas and to stay updated with weather alerts. The severe weather conditions could lead to significant disruptions, with risks of landslides and other weather-related incidents.
In summary, as Rio Grande do Sul faces an unprecedented weather event, the combination of heavy rainfall, strong winds, and potential flooding highlights the need for vigilance and preparedness among residents. The upcoming days will be crucial as the state navigates through this challenging weather pattern.
The average rainfall for the month of May in Rio Grande do Sul typically ranges between 140 mm and 180 mm, indicating that many areas could receive more rain in just a couple of days than usually expected for the entire month. The situation underscores the impact of climate variability and the importance of monitoring weather patterns closely.
As the weather unfolds, residents are advised to remain alert and adhere to safety guidelines issued by local authorities to mitigate the risks associated with severe weather.
