Bart Warner asks: "Todd, how can it be lightning a few seconds apart and I can see the flash but can't hear thunder?"
This is actually pretty common. What you're seeing is regular lightning, it's just too far away to hear the thunder.
Some people call it "heat lightning."
Since sound waves are bent as they move through the air, thunder is typically heard from storms that are closer than 10 miles.
However, under the right conditions, storms can be heard as far as 20 miles away.
To estimate the distance you are from a lightning strike, count the seconds between when you see the lightning and hear the thunder. Take that value and divide by five. The result is the approximate distance, in miles, of the lightning.
Remember, we have a lot of trees and mountains here in East Tennessee. They obstruct view, so the lightning we usually see is pretty close.