The extreme heat warning poses risks of heat-related illnesses, particularly for vulnerable populations such as the elderly, children, and those with pre-existing health conditions. Outdoor activities during peak heat hours should be minimized. While the Valley will remain mostly dry, areas in northern and eastern Arizona may experience localized storms, which could bring sudden changes in weather conditions. Residents in these areas should remain alert to potential flash flooding and lightning hazards [AZFamily, 2026-09-11].