US: High temperatures forecast to persist across central regions through at least Aug. 27

Forecast models indicate excessive temperatures will persist across parts of the central US through at least Aug. 27. A dangerous heat wave is forecast over the Midwest over the coming days. Forecast high temperatures of 35-37 C (95-99 F) with high humidity levels will result in heat indices of 41-46 C (105-115 F). Widespread heat-related advisories and warnings are in place. Minimum temperatures will remain high, with 24-26 C (75-79 F) forecast, providing little relief from the heat overnight. Numerous record highs will be possible over the Midwest and Southeast Aug. 27. An approaching cold front will lower temperatures across parts of the Upper Midwest Aug. 27. The Southern Plains will see some relief from the record heat Aug. 27, but temperatures are likely to remain high, with 35 C (95 F) forecast.

As of early Aug. 26, the NWS has issued excessive heat warnings across parts of northwestern Illinois, eastern Iowa, southeastern Minnesota, and western Wisconsin and excessive heat watches across east central Illinois, northern and central Indiana, far southern Michigan, and far northwestern Ohio. Heat advisories are in place across much of the rest of the affected area. Officials could update and extend the coverage of weather alerts over the coming days.

The high temperatures may result in increased energy and water demand and an increased 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.

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, 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.