A person talks on a cellphone at Wagner Park with temperatures approaching 100 degrees Fahrenheit July 3 in New York City. Photo by John Angelillo/UPI | License Photo

Triple-digit heat is slated to roast a large portion of the central United States through the final days of July as a massive, record-smashing heat dome will build east, warn AccuWeather meteorologists.

The shift comes amid a stifling heat wave across much of the interior West, which saw Phoenix tentatively tie the all-time record high minimum temperature of 97 degrees on Friday morning. By later this weekend and early next week, daytime temperatures in triple-digit territory will become common for millions from the Plains to the Mississippi Valley.

"The core of the brutal heat will gradually shift out of Montana and the Dakotas through Sunday and head farther south and east as we go into next week," said AccuWeather senior meteorologist Joe Lundberg.

Until then, more record highs are ahead for cities such as Billings, Mont., and Bismarck, N.D., where temperatures as high as 107 are forecast through the weekend.