squall

thumb|A video recorded nearing the end of a squall, caused by a dry microburst (strong downdraft); after this video was shot, it started raining. A squall is a sudden, sharp increase in wind speed lasting minutes, as opposed to a wind gust, which lasts for only seconds. They are usually associated with active weather, such as rain showers, thunderstorms, or heavy snow. Squalls refer to the increase of the sustained winds over that time interval, as there may be higher gusts during a squall event. They usually occur in a region of strong sinking air or cooling in the mid-atmosphere. These force strong localized upward motions at the leading edge of the region of cooling, which then enhances local downward motions just in its wake.

==Etymology== There are different versions of the word's origins: By one version, the word appears to be Nordic in origin, but its etymology is considered obscure. It probably has its roots in the word skvala an Old Norse word meaning literally to squeal. By another version, it is an alteration of squeal influenced by bawl.