Good morning,
Monday morning around 6:30, I was on the air talking about a line of thunderstorms moving into Johnson and Saline counties on the Missouri side. At the same time Donna Lindahl of Knob Noster, Missouri was headed out the door on her way to work. What she saw stopped her in her tracks. She went back inside, got her camera and took this picture.
Is it a "Roll Cloud" or Shelf Cloud? At first I thought it might be a roll cloud but upon closer inspection I think it is a shelf cloud. Roll clouds are different from Shelf clouds in that roll clouds are detached from the parent thunderstorm. Here's an example of a roll cloud, notice how it is detached from the parent t-storm cloud above.
Both roll & shelf clouds are associated with gust fronts or rain cooled air that rushes out ahead of a line of thunderstorms, acts like a mini cold front. There was one yesterday that dropped nearby Warrensburg and Sedalia into the 60s.
Looking at this first picture, I thought the cloud appeared detached but this next photo below leads me to believe this is a shelf cloud, which are formed when colder air aloft in the cloud is forced down by heavy rain. Donna says it rained hard after this passed.
Shelf clouds also have more of a semi-circle shape, like this one. Roll clouds sometimes look like a tornado lying on its side.
Great work Donna, great pictures!
Brett