How are tornadoes in the northern hemisphere different from tornadoes in the southern hemisphere?
The sense of rotation is usually the opposite. Most tornadoes — but not all! — rotate cyclonically, which is counterclockwise in the northern hemisphere and clockwise south of the equator. Anticyclonic tornadoes (clockwise-spinning in the northern hemisphere) have been observed, however — usually in the form of waterspouts, non-supercell land tornadoes, or anticyclonic whirls around the rim of a supercell’s mesocyclone. There have been several documented cases of cyclonic and anticyclonic tornadoes under the same thunderstorm at the same time. Anticyclonically rotating supercells with tornadoes are extremely rare; but one struck near Sunnyvale, CA, in 1998. Remember, “cyclonic” tornadoes spin counter-clockwise in the northern hemisphere, and clockwise.
