What are the charachteristics of lightning bolt streamer originators?

Question

How far in advance can the streamer originators be identified before a lightning bolt strikes? Are the streamer originators the same all the time?

Answer 1

In thunderstorms, positive streamers are the ionized currents of air that originate from the ground and extend upward to meet descending step leaders, thereby creating a visible lightning strike.  I assume that by "streamer originator," you mean the object from which the streamer is created.

The streamer is present for approximately 20 milliseconds before meeting the step leader and creating a visible lightning strike.  Prior to the formation of the streamer, it is not possible to determine which object(s) will be the originator(s), so the lead time is capped at about 20 ms.

The streamer originators themselves, however, share some common characteristics.  As a rule, tall, metallic objects are more likely to be the originators than shorter objects that are non-metallic.  Typical streamers include telephone poles, chimneys, trees, and radio towers.  In 95 percent of cases, these objects will become positively charged in the electric field that is created beneath a thunderstorm.  However, objects can become negatively charged if the descending step leader is positively charged.  This rare but well documented phenomenon can occur when a step leader descends not from the base of the thunderstorm, but from the positively charged anvil region of the cloud.

It is important to note that many streamers (perhaps ten to twenty) will form as a stepped-leader descends to the ground, but only one streamer will successfully complete each lightning strike.  Therefore, one streamer originator is struck at a time (although the electricity may be channeled elsewhere).

I hope this information has been helpful!