Brazil's National Institute of Meteorology (Inmet) issued high-level weather alerts for critical relative humidity dropping below 15% across nine states in the Central-West, Southeast, Northeast, and North regions. The intense dry spell affects the Federal District, Goiás, Mato Grosso, Mato Grosso do Sul, Tocantins, and interior sectors of São Paulo, Minas Gerais, Bahia, and Maranhão, combining elevated temperatures with desert-like dryness.
Data from automated weather stations show that the Araguaia river basin and sections of the São Francisco valley are experiencing the sharpest drops, with humidity levels swinging between 12% and 20% during peak afternoon hours. The World Health Organization (WHO) classifies humidity under 20% as an emergency alert, which quickly increases hospital visits for respiratory distress and dehydration in regional hubs such as Goiânia, Cuiabá, and Montes Claros.
The condition stems from a persistent atmospheric blocking system anchored over central South America. This hot, dry air mass prevents cold fronts from pushing northward and cuts off tropical moisture flows from the Amazon basin, accelerating soil water loss in a dynamic tied to shifting global climate circulation patterns.
Fire prevention and health advisories
To reduce the spread of fires across savannah grasslands and agricultural fields, Prevfogo, the national specialized fire management center under environmental agency Ibama, joined state brigades to enforce bans on open-field agricultural burning. State civil defense agencies advised residents to drink extra water, suspend outdoor exercise between 10:00 and 17:00, and use indoor humidifiers or wet towels.
Municipal clinics across the affected states have expanded primary care triage for children and elderly patients suffering from asthma and chronic bronchitis. Forecasters at Inmet project that the high-pressure system will linger over the coming days, requiring steady vigilance from rural communities and city services until rain systems can break through the dry block.