Weekend stormy skies and record temperatures forecast for Fourth of July

Severe storms are forecasted from South to Northeast across the U.S., threatening travel and festivities.
Flash floods are possible, along with damaging wind and hail.
Excessive heat warnings are in effect in the West and South with temperatures reaching over 100 degrees.
Fireworks displays have been postponed in some areas due to weather.
The storms are forecasted to continue after the holiday weekend, impacting 90 million Americans.