Tonight: Heat Advisory until 8:00 PM. Partly cloudy. Low 78. Scattered thunderstorms possible. Tomorrow: Extreme Heat Warning from 11:00 AM to 8:00 PM. Partly cloudy. High 94. Heat index 115. Widespread afternoon thunderstorms possible. Tomorrow night: Extreme Heat Warning until 8:00 PM. Partly cloudy. Low 78. Thunderstorms ending before midnight.