Yes, weather conditions such as turbulence and thunderstorms generate electric fields. According to this theory, electric currents in the Earth's molten core may be responsible for magnetic fields with strengths of up to 500 mG. As DC or static fields, their possible interaction with the human body is different.
What these guidelines are trying to do, instead, is make sure that people aren't being exposed to EMFs that are more powerful than the ones that are already produced by their bodies, brains, and hearts."