Heatwave and high humidity to blast much of US: ‘impactful to anyone’

Much of the central and eastern United States is bracing for a long and dangerous heatwave set to dominate the upcoming week, according to the National Weather Service (NWS).

Temperatures are climbing ahead of the Fourth of July holiday weekend, and the arrival of high humidity will exacerbate the heat, making conditions feel even more oppressive. Already, parts of the US, including Phoenix, central Texas, and much of the Southwest, experienced temperatures around 100°F (38°C) on Sunday.

The NWS has also issued warnings for severe wildfire conditions across the western US, with new fires emerging in the region. On Sunday, over 130 million Americans in southern and Great Plains states were under moderate to severe heat risk conditions. Forecasters predict this area will expand, and temperatures will intensify throughout the week.

Several days of high temperatures, with some exceeding 100°F, are expected across the lower Great Lakes, mid-Atlantic, and the Mississippi and Ohio River valleys. Record highs could be set in areas from the lower Great Lakes to the mid-Atlantic and New England later in the week. Major cities along the East Coast, including New York City, Philadelphia, Washington, and Baltimore, as well as Midwestern cities like Chicago, Indianapolis, St. Louis, and Detroit, are anticipated to see their highest temperatures of the year so far.

The heat is expected to persist into the following weekend across the Great Plains, Southeast, and mid-Atlantic. With high humidity, heat indexes could reach 100-110°F, and in some areas, as high as 115°F. Meteorologists emphasize that this level of heat is "impactful to anyone," not just vulnerable populations, posing a risk to everyone, especially those spending time outdoors during the holiday weekend.

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That’s heat that’s impactful to anyone. It’s not just older adults or younger children or people who are spending a ton of time outdoors, maybe straining themselves a little more than normal. This is heat that really could impact everyone, especially with people outdoors going into the holiday weekend.