Brazil, Uruguay: Adverse weather forecast across the region through at least Sept. 20

Thunderstorms and heavy rainfall are forecast across parts of southeastern Brazil and northern and eastern Uruguay through at least Sept. 20. Storms may be accompanied by strong wind gusts, lightning, and possible hail.

Brazil's National Institue of Meteorology (INMET) has issued orange storm warnings (the middle level on a three-tier scale) across far southwestern Parana, Rio Grande do Sul, and southern and western Santa Catarina states. Rainfall totals of 3-6 cm (1.1-2.4 inches) per hour or 5-10 cm (2-4 inches) per day are forecast, as well as winds of 60-100 kph (37-62 mph) and possible hail storms. Yellow storm warnings are in place across the rest of the affected area in Brazil.

Uruguay's Institute of Meteorology (Inumet) has issued an orange strong storms and heavy rainfall warning (the middle level on a three-tier scale) across Cerro Largo, Rivera, northern Rocha, northern and eastern Tacuarembo, and Treinta y Tres departments. A yellow strong storms and heavy rainfall warning is in effect for the areas surrounding the orange warning area.

Officials could update and possibly extend the coverage of weather alerts over the coming hours and days.

The storms could produce rounds of heavy precipitation, strong winds, and isolated thunderstorm activity in the affected area. Sustained heavy rainfall could trigger flash and areal flooding. Such flooding is possible in low-lying communities near watercourses and other large bodies of water and in urban areas with easily overwhelmed stormwater drainage systems. Sites downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall. Sporadic power outages may occur throughout the affected area.

The severe weather will likely contribute to transport disruptions across parts of the impacted region. Traffic and commercial trucking delays might occur along regional highways. Flooding downpours could inundate some low-lying roads in areas with poor drainage. Strong winds might also pose a hazard to high-profile vehicles. Hazardous weather conditions might cause flight delays and cancellations at regional airports.