Heat/Sheet Lightning |
 Dave Thurlow, Host |
You've most likely heard of people who run fast to have lightning feet, but have you ever heard of lightning from heat, or lightning that looks like a sheet? No this isn't Doctor Suess, it's the Weather Notebook and I'm meteorologist Dave Thurlow.
Lightning, by any one of its many names, is still lightning. But I'd like to talk about a couple of lightning types that are really the same thing. Heat lightning and sheet lightning. Ever heard of these? I remember sitting out in the backyard with all the neighborhood kids on hot summer evenings, putting off going into our houses where the daytime heat was still trapped. Flashbulb-like pops of light would dance around the horizon and some smart alec kid would say Oh that's just heat lightning." The heat lightning would dwindle away to nothing and the parents would call for their broods and off to bed it would be, all the while hoping for some real lightning.
The thing is that heat lightning is real lightning, it's just far away. A thunderstorm dozens of miles away only spreads its flashes of light, not it's thunder, wind or rain. It's called heat lightning because it is on hot nights that small storms can kick up a windy, rainy fuss in one town and leave neighboring towns just viewing this heat lightning. But right underneath the storm, the lightning is called -- lightning -- and it can strikes a nearby tree with a tremendous clap of thunder. Miles away the same bolt is only seen as it back lights the side of a cloud (hence the name sheet lightning) and seems of little consequence. Heat lightning and sheet lightning and lightning lightning are the same thing, just viewed from different backyards.
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