South America: High temperatures forecast to persist in northern Argentina, southern Brazil, and across Paraguay through at least March 15 /update 1

Forecast models indicate that high temperatures will persist across parts of northern Argentina, southern Brazil, and much of Paraguay through at least March 15. Temperatures exceeding 40 C (104) F are possible across parts of the affected area over the coming days.

As of early March 12, Argentina's National Meteorological Service (SENAMHI) has issued red high-temperature warnings (the highest level on a three-tier scale) across parts of northwestern Chaco, central and western Formosa, and northeastern Salta provinces. Yellow high-temperature warnings are in place across the rest of the affected area in northern Argentina.

Brazil's National Institute of Meteorology (INMET) has issued an orange heatwave warning (the middle level on a three-tier scale) across central and southern parts of Mato Grosso do Sul State and most inland areas of Parana, Rio Grande do Sul, Santa Catarina, and Sao Paulo states through March 15. Temperatures of more than 5 C (9 F) above the seasonal average are expected across the affected area.

Paraguay's Directorate of Meteorology and Hydrology has warned of temperatures rising up to 41 C (106 F) in the Eastern Region and 42 C (107 F) in the Western/Chaco Region through March 13.

Officials could upgrade or expand the alerts as the heatwave develops over the coming days.

The high temperatures may result in increased energy and water demand and a heightened risk of heat-related illnesses, such as heat exhaustion and heat stroke.

The extended period of oppressive heat and dry conditions may produce ideal circumstances for further wildfire growth throughout the affected areas. Heatwaves also pose a threat to vulnerable groups - such as the elderly, children, pregnant women, and those with respiratory illnesses - due to the increased possibility of heat stroke or heat exhaustion during prolonged exposure to high temperatures. These health risks could also extend to relatively healthy individuals during significant heatwave events. In addition to significantly impacting athletes and those who work outdoors, high temperatures can cause problems for people using mass transit. The lack of air conditioning and cramped vehicles during rush hour may lead to some passengers being hospitalized for dehydration.

Very high temperatures may warp rail tracks and force passenger and freight trains to operate at reduced speeds. Road surface damage is also possible, and overheated vehicles may worsen traffic problems in urban areas where congestion is already a problem. Commercial trucking disruptions might occur, as very high temperatures put more stress on vehicles, making tire blowouts more common. Major flight disruptions are unlikely at regional airports, but general aviation disruptions are possible, and some airfreight carriers could reduce cargo loads. High temperatures could lead to an increased demand for electricity, which might trigger localized brownouts or blackouts, exacerbating hazardous conditions when air conditioning is no longer possible.