Stories We Like: A Guide to the Comma
A brief, sudden, violent windstorm, often accompanied by rain or snow. A squall is said to occur if a wind having a sustained speed of 40 km (25 mi) per hour lasts at least 1 minute and then decreases rapidly. See also squall line.
as used by weather forecasters, a sudden wind-speed increase of 8 metres per second (18 miles per hour) or more, for one minute or longer. It includes several briefer wind-speed changes, or gusts. A squall is often named for the weather phenomenon that accompanies it, such as rain, hail, or thunder; a line squall is one associated with a squall line of thunderstorms that is often hundreds of kilometres long.