Brazil, Paraguay: Adverse weather forecast across parts of southern Brazil and central Paraguay through at least Sept. 28 /update 1

Event

Thunderstorms and heavy rainfall are forecast across parts of southern Brazil and central Paraguay through at least Sept. 28. Storms may be accompanied by strong wind gusts, lightning, and possible hail. Heavy downpours could trigger flash and urban flooding, as well as landslides on unstable slopes.

As of early Sept. 27, Brazil's National Institute of Meteorology (Inmet) has issued orange storm warnings (the middle level on a three-tier scale) across parts of southern Goias, far southern Mato Grosso, most of Mato Grosso do Sul, southern and southwestern Minas Gerais, northern and western Parana, and eastern, northern, and western Sao Paulo states. Between 3-6 cm (1-2 inches) of rain per hour or 5-10 cm (2-4 inches) of rain per day and winds of 60-100 kph (37-62 mph) are forecast in these orange warning areas.

The Paraguay Directorate of Meteorology and Hydrology has issued a warning for rains with moderate to strong thunderstorms and wind gusts, as well as occasional hail, across central regions of the country for the morning Sept. 27. The affected area includes parts of central and southern Concepcion, San Pedro, northern Cordillera, northern Alto Parana, central and southern Amamby, Canindeyu, and southern President Hayes departments. The directorate has also issued a special bulletin warning of possible thunderstorms over central, northern, and eastern parts of Paraguay through Sept. 28. Rainfall totals of 8-12 cm (3-5 inches) are possible across the affected area, as well of winds of around 100 kph (62 mph).

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 and damaging winds across the affected area. In areas where heavy rainfall occurs, 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 in 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 airports in the region, 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 track inundation. Localized business disruptions may occur in low-lying areas.

Advice

Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments before travel. Make allowances for localized travel delays and potential supply chain disruptions where flooding has been forecast. Do not drive on flooded roads. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

National Institute of Meteorology (Inmet)
Paraguay Directorate of Meteorology and Hydrology