Thunderstorm outflow clouds, timelapse - HD 影片檔

Timelapse footage of the outflow boundary from a large approaching thunderstorm. The outflow boundary is marked by advancing shelf clouds, created when cold air falling from the thunderstorm undercuts warm air in front of it, lifitng it and causing condensation into cloud. This is a similar process to a small scale cold front. The winds associated with such features are hazardous to aircraft. Filmed in the USA on a summer afternoon.