The extreme heat in the central U.S. poses risks for outdoor activities, with heat indices in the triple digits increasing the likelihood of heat-related illnesses. Rain and thunderstorms in the Southeast and Rockies could disrupt holiday plans, particularly on Sunday and Monday. Scattered severe storms are possible in the Ohio Valley and mid-Atlantic regions on Saturday. Monsoonal moisture in the Southwest may fuel thunderstorms, requiring adjustments to outdoor schedules. Cooler conditions in the Northwest may provide relief but could also bring scattered showers.