US: Heatwave forecast to persist across central, southern, and southeastern regions through at least July 7 /update 3

High temperatures are forecast to persist across parts of the central, southern, and southeastern US through at least July 7. Temperatures in excess of 40 C (104 F) are possible across parts of the affected area, with heat indexes (what the temperature feels like to the human body when relative humidity is combined with air temperature) of up to around 48 C (118 F). As of early July 1, the US National Weather Service (NWS) has issued excessive heat warnings for parts of eastern Oklahoma, eastern and southeastern Louisiana, and southern Mississippi. Heat advisories are in place across much of the rest of the affected area. Officials could update and possibly extend the coverage of weather alerts 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. Authorities advise the general public to avoid prolonged exposure to direct sunlight, wear loose and light clothing, and stay hydrated.

The extended period of oppressive heat and dry conditions may produce ideal circumstances for wildfire growth throughout the region. 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.

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 stress vehicles, making tire blowouts more common. Major flight disruptions are unlikely, 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.