Brazil: Adverse weather forecast across far southern regions through at least Sept. 20

Severe weather is forecast across parts of far southern Brazil through at least Sept. 20. As of early Sept. 19, Brazil's National Institute of Meteorology (INMET) has issued an orange storm warning (the middle level on a three-tier scale) across parts of central, northwestern, southern, and western Rio Grande do Sul and western Santa Catarina states through early Sept. 20. Rainfall amounts of 3-6 cm (1.2-2.4 inches) per hour or 5-10 cm (2-4 inches) in 24 hours, winds gusting between 60-100 kph (37-62 mph), and hail are expected in the affected area. Officials could update and possibly extend the coverage of the relevant weather alerts over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. In developed areas with easily overwhelmed stormwater drainage systems, urban flooding is also possible. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil. Power outages and disruptions to telecommunications services are likely where significant flooding, landslides, or strong winds impact utility networks.

Floodwaters and debris flows could render some bridges, rail networks, or roadways impassable, impacting overland travel in affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger intermittent flight delays and cancellations at airports in the affected regions, though these are unlikely to be severe or prolonged. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and track inundation. Localized business disruptions may occur in low-lying areas.