Warm air rises at a steeper angle along a cold / warm front. (highlight your answer) A cold / warm front is most likely to produce clouds of vertical development and perhaps thunderstorms. (highlight your answer) Clouds that create heavy precipitation and perhaps thunder and lightning are called Clouds that are low, gray, and produce light to moderate precipitation are called What part of the U.S. might encounter a collision of a cold, dry air mass (cP) and warm, moist air mass (mT)