GEOG 131 Chapter Notes - Chapter 5.10-5.12: Arcus Cloud, Bow Echo, Virga
Document Summary
Generally begins with horizontal winds moving across the surface. Wind speeds are higher aloft and decrease downward due to friction with the surface: causes vertical wind shear > rotating, subhorizontal vortex. Mechanical turbulence: once it spans the distance from the cloud to ground it is a tornado. Funnel cloud if it does not reach the ground: counterclockwise rotation in the northern hemisphere. Most tornadoes occur in association with multi cell or large supercell thunderstorms, which associated with cold fronts. Wall cloud- distinctive, sharp, low forming cloud: indicates tornado may be near. Enhanced fujita scale (ef scale)- based on estimated wind speed as evidenced by damage to classify tornadoes. Tornado alley- northern texas northward to the dakotas and into canada. Dixie alley- along gulf coast and adjacent inland areas. Waterspout- rotating, columnar vortex of air and small water droplets that is over a body of water: two kinds.
