South America: Adverse weather forecast across parts of northeastern Argentina, far southern Brazil, and Uruguay through at least Sept. 26

Severe weather is forecast across parts of northeastern Argentina, far southern Brazil, and much of Uruguay through at least Sept. 26. A slow-moving cold front over the region is expected to bring thunderstorms accompanied by heavy downpours, strong wind gusts, and possible hail storms over the coming days. 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 Sept. 23, Argentina's National Meteorological Service (SMN) has issued orange thunderstorm warnings (the middle level on a three-tier scale) across much of Entre Rios Province, with the exception of some southern areas. Yellow storm warnings are in place for the rest of Entre Rios and parts of central, southern, and western Corrientes and central and southeastern Santa Fe provinces.

Brazil's National Institute of Meteorology (INMET) has issued an orange storm warning (the middle level on a three-tier scale) across central and southern Rio Grande do Sul State Sept. 23. Rainfall totals of 3-6 cm (1.1-2.4 inches) per hour or 5-10 cm (2-4 inches) per day are expected in the warning area, as well as winds between 60-100 kph (37-62 mph) and possible hail storms.

The Uruguayan Institute of Meteorology (INUMET) has issued a press release warning of strong and occasionally severe storms accompanied by heavy rainfall across the country over the coming days. The worst of the severe weather is expected in northern regions and the central-eastern strip.

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.