On satellite images, a midlatitude cyclone is often identifiable by a comma-shaped cloud mass.
MOVIE (QuickTime 1.3MB): Infrared Satellite Loop
Here is a movie loop of color enhanced infrared images spanning 18 hours. The center of the cyclone was initially located over the southcentral portions of the United States. As the cyclone evolved over time, notice the counterclockwise rotation of clouds around the cyclone center.