The lack of stormy weather across the country will actually lead to over 90% of the country having good viewing weather for the evening fireworks the 4th of July. While thunderstorms will pop-up across parts of the country during the day, most of the storms will be done by 9:00 pm local time. The exceptions will be the Midwest, parts of the Gulf Coast and the Big Bend region of Texas. Those areas will have storms that will last well into the early nighttime hours and may cause delays in firework events. I don’t recall a 4th of July with this dry country-wide in a long time.
The image above is a rather unique graphic from sunsetwx.com showing the sunset weather for 4th of July evening. As you can see, most of the West and Plains will have good sunset weather while the East will be so so. That does not mean the viewing weather for fireworks will be ruin, but it is a unique way at looking at things.
The image below is the simulated radar and satellite combination for 4th of July evening. Notice the lack of rain across the country despite the clouds.