Much of the eastern and southern United States faces another spell of oppressive heat and tropical humidity this weekend, with afternoon temperatures climbing back into the 90s and heat-index readings reaching the low 100°F range. Forecasters say the steamy air will fuel scattered to strong thunderstorms from the Great Lakes to the Gulf Coast. In Michigan, storms are expected to flare after 2–3 p.m. Sunday, while in North Texas a stalled frontal boundary is likely to generate slow-moving cells capable of dumping heavy rain and triggering localized flooding. Similar patterns are forecast for the Susquehanna Valley in Pennsylvania, the Deep South—including Louisiana and Georgia—and parts of Florida and New Mexico. Although Saturday should offer the most dry time for outdoor plans in many areas, meteorologists warn that any storm that develops could produce brief downpours, gusty winds or dangerous lightning. Residents are advised to limit strenuous activity during peak heat, stay hydrated and monitor flash-flood alerts. High heat and humidity are expected to persist into next week even after the current storm chances subside.