Re:NLDN (Score 1)

That is indeed a cool link, but don't forget that it only shows cloud-to-ground lightning, which is only about 10% of all lightning. Vaisala sells that lightning data to power companies so they have a vested interest in filtering out all intracloud lightning. This also means that the data is great at telling you that an established storm is coming, but new storms usually only produce intra-cloud lightning before they get strong enough to produce cloud-to-ground.

For cool non-realtime stuff, check out these satellite-derived summaries.

They give an interesting perspective on lightning distributions. There's more lightning over the North Pacific in the winter than the summer, for example (probably because there are more storms).