Brazil, Uruguay: Adverse weather forecast across portions of far southern Brazil and Uruguay through at least Sept. 20

Event

Thunderstorms with rounds of strong winds, heavy rainfall, hail, and flooding are forecast to occur across portions of far southern Brazil and Uruguay through at least Sept. 20.

Brazil's National Institute of Meteorology has issued an orange storm warning (second-highest level on a four-tier scale) for heavy rain, strong winds, hail, and possible flooding for southern Rio Grande do Sul State. The storm could result in power outages as well as damage crops and trees.

The Uruguayan Institute of Meteorology (Inumet) has issued the following warnings.

• Orange storm warnings (second-highest level on a four-tier scale) for heavy rain, strong winds, hail, and possible flooding for Cerro Largo, eastern Durazno, northern Florida, far northern Lavalleja, Paysandu, Rio Negro, Rivera, northern Rocha, southern Salto, Tacuarembo, and Treinta y Tres departments.

• Yellow storm warnings for the rest of Uruguay.

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

Hazardous Conditions
The storms will be capable of producing heavy downpours, damaging winds, and hail across the affected area. Should sustained heavy rainfall occur, it could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located 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 the soil has become saturated by heavy rainfall. Disruptions to electricity and telecommunications services are possible where significant flooding, landslides, or strong winds impact utility networks.

Transport
Floodwaters and debris flows could render some bridges, rail networks, or roadways impassable, impacting overland travel around 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 regional airports, 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 that see heavy rainfall and potential track inundation. Localized business disruptions may occur in low-lying areas.

Advice

Confirm flights. Monitor local media for updated emergency and weather information. Seek updated information on weather and road conditions before driving or routing shipments through areas where severe weather is forecast. Plan accordingly for potential delivery delays if routing shipments by truck through the affected area. Do not attempt to drive through flooded areas. Review contingency plans and be prepared to move quickly to shelter if tornado warnings are issued. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

Instituto Nacional de Meteorologia, Brazil (Portuguese)
Uruguayan Institute of Meteorology (Spanish)