As a line of thunderstorms approached Columbia this evening, our daughter called our attention to mammatus clouds above the city. Indeed, a broad area of dipping lobes was observed overhead, the product of sinking air beneath the advancing cummulonimbus clouds.
Often associated with severe thunderstorms, mammatus clouds (named for their breast-like shape) have long been rumored to predict the development of tornadoes. However, though their development indicates a potent updraft within the thunderstorm, mammatus clouds are actually most commonly associated with weakening storms. Nevertheless, they do indicate the presence of wind shear, ice crystals and potent temperature gradients and weather-savvy pilots know to avoid these cloud formations.
For those of us on the ground, mammatus clouds offer a beautiful sight, especially when illuminated by a rising or setting sun; my thanks to Ally for the heads-up! Fortunately (or unfortunately) we should have more opportunities to observe these clouds this weekend as a potent storm system moves in from the west.