A cluster of thunderstorms moved south of D.C. yesterday allowing for a spectacular cloud show right around sunset. The unusual clouds that many people were noticing were the clouds that seemed to bubble down from above, looking like balloons. These are called Mammatus Clouds.Mammatus Clouds in Hartwood, VA sent in by Robert Rufio
These clouds often form on the under side of anvil clouds. For a little more detailed explanation, the University of Illinois at Urbana-Champaign's Department of Atmospheric Sciences has a great website that explains all kinds of atmospheric phenomenon.Michelle Schrotz from Richmond, VA sent this picture in
As far as mammatus clouds are concerned, "As updrafts carry precipitation enriched air to the cloud top, upward momentum is lost and the air begins to spread out horizontally, becoming a part of the anvil cloud. Because of its high concentration of precipitation particles (ice crystals and water droplets), the saturated air is heavier than the surrounding air and sinks back towards the earth.Thornburg, VA mammatus from Brittney Wagner
The temperature of the subsiding air increases as it descends. However, since heat energy is required to melt and evaporate the precipitation particles contained within the sinking air, the warming produced by the sinking motion is quickly used up in the evaporation of precipitation particles. If more energy is required for evaporation than is generated by the subsidence, the sinking air will be cooler than its surroundings and will continue to sink downward."Mammatus in Fairfax from Meteorologist Alex Liggitt
In addition to the mammatus clouds, the sunset was phenomenal as well as far as Fairfax was concerned. Here were a few other shots I captured last night. Hope you like them!