 Then a cool front approaches later Saturday into Sunday. Thunderstorms may be more numerous. Ahead of the front, high temperatures will be well into the 80s, maybe even 90 in parts of the mid-Atlantic. That's surging warmth and humidity, boosting thunderstorms where some could reach severe levels. Then muggy conditions are on store region-wide for Saturday night. Lows in most areas only in the mid-60s to mid-70s.