Forecasters warn that a broad swath of the western and central United States will bake under unusually high temperatures through early next week. The National Weather Service has issued an Extreme Heat Warning for metro Phoenix from Sunday through Tuesday, with temperatures expected to peak at 116°F on Monday. Utah will run up to 10°F above normal by Tuesday, while Seattle may briefly touch 90°F. Elsewhere across the High Plains and Great Lakes, hot and humid conditions will dominate Sunday and Monday, accompanied by scattered afternoon thunderstorms. Relief is possible later in the week as Monsoon 2025 pushes moisture northward. Meteorologists expect the first phase—strong winds and blowing dust—early in the week, evolving into heavier rain and a flash-flood threat across southern Arizona and portions of Utah by mid- to late week. Phoenix carries a 20 percent chance of storms on Thursday, with daytime highs forecast to slip back toward the low 100s. Travelers and outdoor workers are advised to limit exposure during peak heat and monitor rapidly changing weather conditions.