A high-risk storm warning is active across Southern Brazil. The National Institute of Meteorology (INMET) has placed the entire state of Paraná, parts of Santa Catarina, and northern Rio Grande do Sul on alert due to a severe weather system.
The instability is driven by an extratropical cyclone advancing over South America, bringing heavy rainfall, damaging winds, and hail.
The Immediate Threat
Meteorologists warn that the incoming system is highly volatile. Residents in the affected zones should prepare for severe conditions, including:
- Heavy Rainfall: Expected precipitation between 30 to 60 mm per hour, or up to 100 mm daily.
- Severe Winds: High-velocity gusts capable of downing trees and power lines.
- Hail Hazards: High potential for localized hail storms damaging vehicles and crops.
- Infrastructure Risks: High risk of urban flooding, sudden power outages, and agricultural damage.
In response to the wind hazards, emergency services advise the public not to seek shelter under trees or near transmission towers, and to unplug major household appliances to prevent surge damage.
Understanding the Science
The driving force behind this severe weather is an extratropical cyclone.
These are low-pressure atmospheric systems that form in middle latitudes, far from the equator. They develop when a cold air mass collides with a warm air mass, causing winds to rotate in a circular pattern around a low-pressure center.
While highly common in North America, Europe, and Asia, these systems regularly impact southern Brazil, leading to intense rainfall, sharp temperature shifts, and high winds.
The Weather Forecast: What's Next
The storm system is expected to linger, impacting the region over the next 48 hours.
- Sunday: Atmospheric instability remains high. By Sunday evening, the entire state of Rio Grande do Sul will be under an orange "danger" alert. Temperatures are rising, with Curitiba seeing a low of 15°C and Porto Alegre ranging from 18°C to 27°C.
- Monday: The storm footprint expands. Severe weather alerts will cover nearly all of Paraná, Santa Catarina, and Rio Grande do Sul. Temperatures will stabilize, with Curitiba starting at 17°C, Florianópolis at 20°C, and all three state capitals projected to reach a maximum of 25°C.
Local authorities urge residents in low-lying or flood-prone areas to monitor official updates and prepare emergency plans.
