The actual phenomenon commonly called heat lightning is simply cloud to ground lighting that occurs very far away, with thunder that dissipates before it reaches the observer. At night, it is possible to see the flashes of lightning from very far distances, up to 100 miles but the sound does not carry that far. In Florida, this type of lightning is often seen over the water at night, the remnants of storms that formed during the day along a sea breeze front coming in from the opposite coast.
On this night we were on the coast of Saint Petersburg, Fl. It was the 4th of July and as the fireworks began, in the distance, flashes of lighting were filling the sky.