Add Yahoo as a preferred source to see more of our stories on Google. A giant supercell hovered in the sky over northwest Oklahoma, as the National Weather Service (NWS) warned of severe thunderstorms ...

In about 15 minutes, Tempe recorded nearly three-quarters of an inch of rain. A supercell thunderstorm forms when wind speed and direction change with height, a phenomenon called wind shear.

Supercells are basically thunderstorms on steroids. These storms create some of the most violent tornadoes and can leave a path of incredible destruction. A supercell is a powerful, long-lived ...