Rio de Janeiro is bracing for a tumultuous weather weekend, with forecasts predicting heavy rains and potential flooding across the city. According to Climatempo, the upcoming days will see rainfall volumes exceeding the monthly average, raising alarms for residents in vulnerable areas.
The weather shift begins on Thursday, April 3, 2025, as a pre-frontal system arrives, heralding a cold front that will sweep through the state starting Friday, April 4. On Thursday, temperatures are expected to soar to a high of 36°C, with isolated rain showers bringing about 15mm of precipitation. However, the calm will soon give way to more severe weather.
On Friday, the cold front will hit Rio, leading to intense rain, a drop in temperatures, and moderate to strong winds. The forecast predicts a maximum temperature of 31°C and a minimum of 21°C. Rain will spread across the city, with the possibility of thunderstorms and lightning strikes.
Saturday, April 5, is anticipated to be the most critical day, with forecasts indicating that rainfall could accumulate to 70mm within 24 hours. Temperatures are expected to plummet, with highs only reaching 26°C and lows at 21°C. The situation is compounded by a severe weather alert issued by Alerta Rio, which highlights that the total rainfall for the weekend could exceed 120mm, surpassing the historical average for the entire month of April, which stands at 112.8mm.
As the storm progresses into Sunday, April 6, the weather will remain unstable, with weak to moderate rain expected throughout the day. The sky will be predominantly cloudy, with temperatures ranging from 17°C to 25°C. Winds will continue at moderate intensity, keeping residents on edge.
Residents are urged to stay vigilant, especially in areas prone to flooding and landslides. The Climatempo has reinforced warnings about the risks of flooding, landslides, and overflowing rivers in these vulnerable zones. The Rio de Janeiro City Hall Operations Center (COR) is advising residents to heed communications and avoid high-risk areas during intense rainfall.
In addition to the heavy rainfall, the Southeast Region of Brazil is under a maximum alert for an extreme rain event, particularly affecting Rio de Janeiro and São Paulo. The Extreme Forecast Index (EFI) from the ECMWF model indicates that this weather event will rank among the most severe in the region's history, with precipitation levels significantly exceeding normal expectations.
Between Saturday and Sunday, April 5-6, the EFI indicates that precipitation in the eastern part of the Southeast Region will be extreme, with values marking it as one of the 1% most extreme events recorded. This alarming forecast highlights the destructive potential of the incoming storm, especially in areas that have historically suffered from landslides and flooding.
The ECMWF model predicts that rainfall totals could exceed 300mm over just two days, particularly impacting the coastal regions of São Paulo and Rio de Janeiro, as well as their mountainous areas. These regions are known for their vulnerability to such natural disasters, having seen tragic outcomes in the past.
Specific forecasts for the state of São Paulo include significant rainfall amounts as follows: Cubatão (170mm), Paranapiacaba (180mm), Rio Grande da Serra (160mm), Ubatuba (214mm), and Itamambuca (200mm). In Rio de Janeiro, the hardest-hit areas are expected to include Sossego (300mm), Petrópolis and Cachoeiras de Macacu (230mm), Teresópolis and Angra dos Reis (214mm), and Tarituba and Mambucaba (240mm).
This extreme weather is exacerbated by unusually high sea surface temperatures in the South Atlantic Ocean, which have recorded anomalies of over 2°C above average. This warming increases moisture availability in the atmosphere, intensifying the forthcoming precipitation as the cold front approaches.
As the situation develops, residents in flood-prone neighborhoods are advised to follow safety guidelines from local authorities and the Civil Defense. If possible, those living in high-risk areas should seek temporary shelter elsewhere to ensure their safety during this hazardous weather event.
With such dire predictions, the coming weekend in Rio de Janeiro is set to be a test of resilience for the city’s inhabitants. As they prepare for the storm, the focus remains on safety and preparedness, with hopes that the community will weather the storm together.
