South America: Adverse weather forecast across parts of the region through at least June 26 /update 1

Thunderstorms accompanied by heavy downpours, strong wind gusts, and possible hail storms are forecast across parts of northeastern Argentina, southern Brazil, and central and southern Paraguay through at least June 26. 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 24, Argentina's National Meteorological Service (SMN) has issued yellow thunderstorm warnings (the lowest level on a three-tier scale) across Misiones Province.

Brazil's National Institute of Meteorology (INMET) has issued orange storm warnings (the middle level on a three-tier scale) across Santa Catarina and parts of southern and western Parana and northern Rio Grande do Sul states. Yellow storm warnings have been issued across parts of central, southeastern, and western Parana and central, eastern, and western Rio Grande do Sul states. After a slightly dryer day on June 25, further showers and storms are expected in the affected region on June 26. 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; further adverse weather may hamper ongoing recovery efforts and trigger additional flooding.

Paraguay's Directorate of Meteorology and Hydrology has issued a warning for heavy rainfall with moderate to strong thunderstorms, strong winds, and possible hail across central, eastern, and southern parts of the Eastern Region and southern parts of the Western region early June 24. Rainfall and storms are expected to continue across much of the Eastern and parts of the Western regions June 24. Isolated showers are expected to linger June 25 before conditions improve June 26.

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.