A surge of heat and humidity as a warm front lifts north, pushing temperatures to around 90 degrees with heat indices topping 100 in spots. Isolated storms could develop in the afternoon and evening, with a cold front stalling nearby Sunday and briefly easing humidity. Another warm front Monday will keep conditions warm and unsettled before a stronger cold front crosses the region Tuesday, bringing a renewed risk of thunderstorms. High pressure will build midweek, delivering drier and more comfortable weather.