Underside of a shelf cloud in Minnesota which brought a temperature drop of 20° Fahrenheit (11° C) from 85° F to 65° F as it passed.

A shelf cloud is a low, horizontal wedge-shaped arcus cloud, associated with a thunderstorm gust front (or occasionally with a cold front, even in the absence of thunderstorms). Unlike the roll cloud, the shelf cloud is attached to the base of the parent cloud above it (usually a thunderstorm). Rising cloud motion often can be seen in the leading (outer) part of the shelf cloud, while the underside often appears turbulent, boiling, and wind-torn. State nickname: North Star State Other U.S. States Capital Saint Paul Largest city Minneapolis Governor Tim Pawlenty Official languages None Area 225,365 km² (12th)  - Land 206,375 km²  - Water 18,990 km² (8. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... An arcus is a low, horizontal cloud formation associated with the leading edge of thunderstorm outflow (i. ... A rolling thundercloud over Enschede, The Netherlands. ... A gust front is a weather front that is the leading edge of gusty surface winds from thunderstorm downdrafts; sometimes associated with a shelf cloud or roll cloud. ... In meteorology, a weather front is a boundary between two air masses with differing characteristics (e. ... A roll cloud is a low, horizontal tube-shaped arcus cloud associated with a thunderstorm gust front (or sometimes with a cold front). ... Cumulus of fair weather A cloud is a visible mass of condensed water droplets or ice crystals suspended in the atmosphere above Earths (or another planetary bodys) surface. ...