South America: Adverse weather forecast across northeastern Argentina, southern Brazil, central and southern Paraguay, and Uruguay through at least June 23

Thunderstorms accompanied by heavy downpours, strong wind gusts, and possible hail storms are forecast across parts of northeastern Argentina, southern Brazil, central and southern Paraguay, and much of Uruguay through at least June 23. Heavy rainfall could trigger flooding in low-lying areas in affected regions and landslides on unstable slopes. Strong winds may cause power outages and property damage.

As of early June 21, Argentina's National Meteorological Service (SMN) has issued yellow thunderstorm warnings (the lowest level on a three-tier scale) across much of Corrientes Province.

Brazil's National Institute of Meteorology (INMET) has issued an orange storm warning (the middle level on a three-tier scale) across western Rio Grande do Sul State and yellow storm warnings across the rest of Rio Grande do Sul and parts of southern and western Santa Catarina states. Many areas of Rio Grande do Sul are still recovering from major flooding in April and May that caused a high number of casualties, mass displacements, and widespread disruptions across the state.

Paraguay's Directorate of Meteorology and Hydrology has issued a special weather bulletin for storms across the Eastern Region and central and southern parts of the Western Region June 21. Isolated showers are expected in parts of the country June 22 before more intense rainfall returns June 23.

The Uruguayan Institute of Meteorology (INUMET) has issued a press release warning of intense storms June 21-23. Storms are expected to move in from western coastal regions June 21 and spread across the country, with the worst of the severe weather expected south of the Rio Negro June 22. Weather conditions are expected to gradually improve June 23.

Officials could update and possibly extend the coverage of weather alerts over the coming 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 located downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall.

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.