Lightning doesn't flash the sky or the ground. You can only see the lightning bolt and hear it.
Steps to reproduce
1. Turn on rain and thunder
2. Wait for lightning
Please confirm. Tested on different versions of java.
Environment
Windows 7 Home Premium 64-bit
Java version "1.7.0_02-ea"
Java(TM) SE Runtime Environment (build 1.7.0_02-ea-b08)
Java Hotspot(TM) 64-bit Server VM (build 22.0-b06, mixed mode)
Yeah, I didn't notice until now that you mention it. I can confirm this although I can't confirm it OFFICIALLY... Thunderstorms suck even more now...